Design of Dual-Mode Local Oscillators Using CMOS Technology for Motion Detection Sensors

Directory of Open Access Journals (Sweden)

Keum-Won Ha

2018-04-01

Full Text Available Recently, studies have been actively carried out to implement motion detecting sensors by applying radar techniques. Doppler radar or frequency-modulated continuous wave (FMCW radar are mainly used, but each type has drawbacks. In Doppler radar, no signal is detected when the movement is stopped. Also, FMCW radar cannot function when the detection object is near the sensor. Therefore, by implementing a single continuous wave (CW radar for operating in dual-mode, the disadvantages in each mode can be compensated for. In this paper, a dual mode local oscillator (LO is proposed that makes a CW radar operate as a Doppler or FMCW radar. To make the dual-mode LO, a method that controls the division ratio of the phase locked loop (PLL is used. To support both radar mode easily, the proposed LO is implemented by adding a frequency sweep generator (FSG block to a fractional-N PLL. The operation mode of the LO is determined by according to whether this block is operating or not. Since most radar sensors are used in conjunction with microcontroller units (MCUs, the proposed architecture is capable of dual-mode operation by changing only the input control code. In addition, all components such as VCO, LDO, and loop filter are integrated into the chip, so complexity and interface issues can be solved when implementing radar sensors. Thus, the proposed dual-mode LO is suitable as a radar sensor.

Towards model-based control of RCCI-CDF mode-switching in dual fuel engines

NARCIS (Netherlands)

Indrajuana, Armando; Bekdemir, C.; Feru, E.; Willems, F.P.T.

2018-01-01

The operation of a dual fuel combustion engine using combustion mode-switching offers the benefit of higher thermal efficiency compared to single-mode operation. For various fuel combinations, the engine research community has shown that running dual fuel engines in Reactivity Controlled Compression

Dual-mode ultraflow access networks: a hybrid solution for the access bottleneck

Science.gov (United States)

Kazovsky, Leonid G.; Shen, Thomas Shunrong; Dhaini, Ahmad R.; Yin, Shuang; De Leenheer, Marc; Detwiler, Benjamin A.

2013-12-01

Optical Flow Switching (OFS) is a promising solution for large Internet data transfers. In this paper, we introduce UltraFlow Access, a novel optical access network architecture that offers dual-mode service to its end-users: IP and OFS. With UltraFlow Access, we design and implement a new dual-mode control plane and a new dual-mode network stack to ensure efficient connection setup and reliable and optimal data transmission. We study the impact of the UltraFlow system's design on the network throughput. Our experimental results show that with an optimized system design, near optimal (around 10 Gb/s) OFS data throughput can be attained when the line rate is 10Gb/s.

Visualization of multipolar longitudinal and transversal surface plasmon modes in nanowire dimers.

Science.gov (United States)

Alber, Ina; Sigle, Wilfried; Müller, Sven; Neumann, Reinhard; Picht, Oliver; Rauber, Markus; van Aken, Peter A; Toimil-Molares, Maria Eugenia

2011-12-27

We study the transversal and longitudinal localized surface plasmon resonances in single nanowires and nanowire dimers excited by the fast traveling electron beam in a transmission electron microscope equipped with high-resolution electron energy-loss spectroscopy. Bright and dark longitudinal modes up to the fifth order are resolved on individual metallic nanowires. On nanowire dimers, mode splitting into bonding and antibonding is measured up to the third order for several dimers with various aspect ratio and controlled gap size. We observe that the electric field maxima of the bonding modes are shifted toward the gap, while the electric field maxima of the antibonding modes are shifted toward the dimer ends. Finally, we observe that the transversal mode is not detected in the region of the dimer gap and decays away from the rod more rapidly than the longitudinal modes.

A dual-mode driver IC with monolithic negative drive-voltage capability and digital current-mode controller for depletion-mode GaN HEMT

NARCIS (Netherlands)

Wen, Y.; Rose, M.; Fernandes, R.; van Otten, R.; Bergveld, H.J.; Trescases, O.

2017-01-01

This work presents a driver and controller integrated circuit (IC) for depletion-mode gallium nitride (GaN) high-electron-mobility transistors (HEMTs). The dual-mode driver can be configured for cascode-drive (CD) or HEMT-drive (HD) mode. In the CD mode, a cascode low-voltage DMOS is driven to

Analysis of dual-mode lasing characteristics in a 1310-nm optically injected quantum dot distributed feedback laser

Science.gov (United States)

Raghunathan, R.; Olinger, J.; Hurtado, A.; Grillot, F.; Kovanis, V.; Lester, L. F.

2015-03-01

Recent work has shown the Quantum Dot (QD) material system to be well-suited to support dual-mode lasing. In particular, optical injection from a master laser (ML) into the residual Fabry-Perot (FP) modes of a 1310 nm Quantum Dot Distributed Feedback (QD-DFB) laser has been recently demonstrated to offer a highly reliable platform for stable dual-mode lasing operation. External controls on the ML, such as operating temperature and bias current, can be used to precisely adjust the spacing between the two lasing modes. This tunability of modeseparation is very promising for a range of applications requiring the generation of microwave, millimeter wave and terahertz signals. Considering the versatility and utility of such a scheme, it is imperative to acquire a deeper understanding of the factors that influence the dual-mode lasing process, in order to optimize performance. Toward this end, this paper seeks to further our understanding of the optically-injected dual-mode lasing mechanism. For fixed values of optical power injected into each FP residual mode and wavelength detuning, the dual-mode lasing characteristics are analyzed with regard to important system parameters such as the position and the intensity of the injected residual mode (relative to the Bragg and the other residual FP modes of the device) for two similarly-fabricated QD-DFBs. Results indicate that for dual mode lasing spaced less than 5 nm apart, the relative intensity of the injected FP mode and intracavity noise levels are critical factors in determining dual mode lasing behavior. Insight into the dual-mode lasing characteristics could provide an important design guideline for the master and QD-DFB slave laser cavities.

Financial Management of Distance Learning in Dual-Mode Institutions

Science.gov (United States)

Rumble, Greville

2012-01-01

Dual-mode universities operating in a tough economic environment need to be able to answer a range of questions concerning their use of different teaching modes accurately and with confidence. Only an activity-based costing approach will provide them with this tool. Cost studies of other distance learning projects may provide benchmarks against…

[Application of second generation dual-source computed tomography dual-energy scan mode in detecting pancreatic adenocarcinoma].

Science.gov (United States)

Xue, Hua-dan; Liu, Wei; Sun, Hao; Wang, Xuan; Chen, Yu; Su, Bai-yan; Sun, Zhao-yong; Chen, Fang; Jin, Zheng-yu

2010-12-01

To analyze the clinical value of multiple sequences derived from dual-source computed tomography (DSCT) dual-energy scan mode in detecting pancreatic adenocarcinoma. Totally 23 patients with clinically or pathologically diagnosed pancreatic cancer were enrolled in this retrospective study. DSCT (Definition Flash) was used and dual-energy scan mode was used in their pancreatic parenchyma phase scan (100kVp/230mAs and Sn140kVp/178mAs) . Mono-energetic 60kev, mono-energetic 80kev, mono-energetic 100kev, mono-energetic 120kev, linear blend image, non-linear blend image, and iodine map were acquired. pancreatic parenchyma-tumor CT value difference, ratio of tumor to pancreatic parenchyma, and pancreatic parenchyma-tumor contrast to noise ratio were calculated. One-way ANOVA was used for the comparison of diagnostic values of the above eight different dual-energy derived sequences for pancreatic cancer. The pancreatic parenchyma-tumor CT value difference, ratio of tumor to pancreatic parenchyma, and pancreatic parenchyma-tumor contrast to noise ratio were significantly different among eight sequences (P<0.05) . Mono-energetic 60kev image showed the largest parenchyma-tumor CT value [ (77.53 ± 23.42) HU] , and iodine map showed the lowest tumor/parenchyma enhancement ratio (0.39?0.12) and the largest contrast to noise ratio (4.08 ± 1.46) . Multiple sequences can be derived from dual-energy scan mode with DSCT via multiple post-processing methods. Integration of these sequences may further improve the sensitivity of the multislice spiral CT in the diagnosis of pancreatic cancer.

High-frequency dual mode pulsed wave Doppler imaging for monitoring the functional regeneration of adult zebrafish hearts

Science.gov (United States)

Kang, Bong Jin; Park, Jinhyoung; Kim, Jieun; Kim, Hyung Ham; Lee, Changyang; Hwang, Jae Youn; Lien, Ching-Ling; Shung, K. Kirk

2015-01-01

Adult zebrafish is a well-known small animal model for studying heart regeneration. Although the regeneration of scars made by resecting the ventricular apex has been visualized with histological methods, there is no adequate imaging tool for tracking the functional recovery of the damaged heart. For this reason, high-frequency Doppler echocardiography using dual mode pulsed wave Doppler, which provides both tissue Doppler (TD) and Doppler flow in a same cardiac cycle, is developed with a 30 MHz high-frequency array ultrasound imaging system. Phantom studies show that the Doppler flow mode of the dual mode is capable of measuring the flow velocity from 0.1 to 15 cm s−1 with high accuracy (p-value = 0.974 > 0.05). In the in vivo study of zebrafish, both TD and Doppler flow signals were simultaneously obtained from the zebrafish heart for the first time, and the synchronized valve motions with the blood flow signals were identified. In the longitudinal study on the zebrafish heart regeneration, the parameters for diagnosing the diastolic dysfunction, for example, E/Em < 10, E/A < 0.14 for wild-type zebrafish, were measured, and the type of diastolic dysfunction caused by the amputation was found to be similar to the restrictive filling. The diastolic function was fully recovered within four weeks post-amputation. PMID:25505135

A dual-mode proximity sensor with integrated capacitive and temperature sensing units

International Nuclear Information System (INIS)

Qiu, Shihua; Huang, Ying; He, Xiaoyue; Sun, Zhiguang; Liu, Ping; Liu, Caixia

2015-01-01

The proximity sensor is one of the most important devices in the field of robot application. It can accurately provide the proximity information to assistant robots to interact with human beings and the external environment safely. In this paper, we have proposed and demonstrated a dual-mode proximity sensor composed of capacitive and resistive sensing units. We defined the capacitive type proximity sensor perceiving the proximity information as C-mode and the resistive type proximity sensor detecting as R-mode. Graphene nanoplatelets (GNPs) were chosen as the R-mode sensing material because of its high performance. The dual-mode proximity sensor presents the following features: (1) the sensing distance of the dual-mode proximity sensor has been enlarged compared with the single capacitive proximity sensor in the same geometrical pattern; (2) experiments have verified that the proposed sensor can sense the proximity information of different materials; (3) the proximity sensing capability of the sensor has been improved by two modes perceive collaboratively, for a plastic block at a temperature of 60 °C: the R-mode will perceive the proximity information when the distance d between the sensor and object is 6.0–17.0 mm and the C-mode will do that when their interval is 0–2.0 mm; additionally two modes will work together when the distance is 2.0–6.0 mm. These features indicate our transducer is very valuable in skin-like sensing applications. (paper)

Dual-Pump CARS Measurements in the University of Virginia's Dual-Mode Scramjet: Configuration "C"

Science.gov (United States)

Cutler, Andrew D.; Magnotti, Gaetano; Cantu, Luca; Gallo, Emanuela; Danehy, Paul M.; Rockwell, Robert; Goyne, Christopher; McDaniel, James

2013-01-01

Measurements have been conducted at the University of Virginia Supersonic Combustion Facility in configuration C of the dual-mode scramjet. This is a continuation of previously published works on configuration A. The scramjet is hydrogen fueled and operated at two equivalence ratios, one representative of the scram mode and the other of the ram mode. Dual-pump CARS was used to acquire the mole fractions of the major species as well as the rotational and vibrational temperatures of N2. Developments in methods and uncertainties in fitting CARS spectra for vibrational temperature are discussed. Mean quantities and the standard deviation of the turbulent fluctuations at multiple planes in the flow path are presented. In the scram case the combustion of fuel is completed before the end of the measurement domain, while for the ram case the measurement domain extends into the region where the flow is accelerating and combustion is almost completed. Higher vibrational than rotational temperature is observed in those parts of the hot combustion plume where there is substantial H2 (and hence chemical reaction) present.

Physics and technology of tunable pulsed single longitudinal mode ...

Indian Academy of Sciences (India)

Design and technology demonstration of compact, narrow bandwidth, high repetition rate, tunable SLM dye lasers in two different configurations, namely Littrow and grazing incidence grating (GIG), were carried out in our lab at BARC, India. The single longitudinal mode (SLM) dye laser generates single-mode laser beams ...

Resonance Excitation of Longitudinal High Order Modes in Project X Linac

Energy Technology Data Exchange (ETDEWEB)

Khabiboulline, T.N.; Sukhanov, A.AUTHOR = Awida, M.; Gonin, I.; Lunin, A.AUTHOR = Solyak, N.; Yakovlev, V.; /Fermilab

2012-05-01

Results of simulation of power loss due to excitation of longitudinal high order modes (HOMs) in the accelerating superconducting RF system of CW linac of Project X are presented. Beam structures corresponding to the various modes of Project X operation are considered: CW regime for 3 GeV physics program; pulsed mode for neutrino experiments; and pulsed regime, when Project X linac operates as a driver for Neutrino Factory/Muon Collider. Power loss and associated heat load due to resonance excitation of longitudinal HOMs are shown to be small in all modes of operation. Conclusion is made that HOM couplers can be removed from the design of superconducting RF cavities of Project X linac.

Resonance Excitation of Longitudinal High Order Modes in Project X Linac

International Nuclear Information System (INIS)

Gonin, I.V.; Khabiboulline, T.N.; Lunin, A.; Solyak, N.; Sukhanov, A.I.; Yakovlev, V.P.; Awida, M.H.

2012-01-01

Results of simulation of power loss due to excitation of longitudinal high order modes (HOMs) in the accelerating superconducting RF system of CW linac of Project X are presented. Beam structures corresponding to the various modes of Project X operation are considered: CW regime for 3 GeV physics program; pulsed mode for neutrino experiments; and pulsed regime, when Project X linac operates as a driver for Neutrino Factory/Muon Collider. Power loss and associated heat load due to resonance excitation of longitudinal HOMs are shown to be small in all modes of operation. Conclusion is made that HOM couplers can be removed from the design of superconducting RF cavities of Project X linac.

Design of dual-mode optical fibres for the FTTH applications

Science.gov (United States)

Chen, Ming-Yang; Li, Yu-Rong; Zhang, Yin; Zhu, Yuan-Feng; Zhang, Yong-Kang; Zhou, Jun

2011-01-01

We present in this article a proposal and design for dual-mode optical fibres for fibre-to-the-home applications. High-order modes in the fibre can be effectively suppressed by the connection of the fibre with standard single-mode optical fibres at the two ends of the fibre. The alignment tolerance at the splicing process is presented. In particular, a low bending loss operation with low splice loss is demonstrated using the proposed technique.

Design of dual-mode optical fibres for the FTTH applications

International Nuclear Information System (INIS)

Chen, Ming-Yang; Li, Yu-Rong; Zhang, Yin; Zhu, Yuan-Feng; Zhang, Yong-Kang; Zhou, Jun

2011-01-01

We present in this article a proposal and design for dual-mode optical fibres for fibre-to-the-home applications. High-order modes in the fibre can be effectively suppressed by the connection of the fibre with standard single-mode optical fibres at the two ends of the fibre. The alignment tolerance at the splicing process is presented. In particular, a low bending loss operation with low splice loss is demonstrated using the proposed technique

Longitudinal-bending mode micromotor using multilayer piezoelectric actuator.

Science.gov (United States)

Yao, K; Koc, B; Uchino, K

2001-07-01

Longitudinal-bending mode ultrasonic motors with a diameter of 3 mm were fabricated using stacked multilayer piezoelectric actuators, which were self-developed from hard lead zirconate titanate (PZT) ceramic. A bending vibration was converted from a longitudinal vibration with a longitudinal-bending coupler. The motors could be bidirectionally operated by changing driving frequency. Their starting and braking torque were analyzed based on the transient velocity response. With a load of moment of inertia 2.5 x 10(-7) kgm2, the motor showed a maximum starting torque of 127.5 microNm. The braking torque proved to be a constant independent on the motor's driving conditions and was roughly equivalent to the maximum starting torque achievable with our micromotors.

Dual comb generation from a mode-locked fiber laser with orthogonally polarized interlaced pulses.

Science.gov (United States)

Akosman, Ahmet E; Sander, Michelle Y

2017-08-07

Ultra-high precision dual-comb spectroscopy traditionally requires two mode-locked, fully stabilized lasers with complex feedback electronics. We present a novel mode-locked operation regime in a thulium-holmium co-doped fiber laser, a frequency-halved state with orthogonally polarized interlaced pulses, for dual comb generation from a single source. In a linear fiber laser cavity, an ultrafast pulse train composed of co-generated, equal intensity and orthogonally polarized consecutive pulses at half of the fundamental repetition rate is demonstrated based on vector solitons. Upon optical interference of the orthogonally polarized pulse trains, two stable microwave RF beat combs are formed, effectively down-converting the optical properties into the microwave regime. These co-generated, dual polarization interlaced pulse trains, from one all-fiber laser configuration with common mode suppression, thus provide an attractive compact source for dual-comb spectroscopy, optical metrology and polarization entanglement measurements.

A flexible dual-mode proximity sensor based on cooperative sensing for robot skin applications

Science.gov (United States)

Huang, Ying; Cai, Xia; Kan, Wenqing; Qiu, Shihua; Guo, Xiaohui; Liu, Caixia; Liu, Ping

2017-08-01

A flexible dual-mode proximity sensor has been designed and implemented, which is capable of combining capacitive-resistive detection in this paper. The capacitive type proximity sensor detecting is defined as mode-C, and the resistive type proximity sensor detecting is defined as mode-R. The characteristics of the proximity sensor are as follows: (1) the theoretical mode is developed which indicates that this proximity sensor can reflect proximity information accurately; (2) both sensing modes are vertically integrated into a sandwich-like chip with an 8 mm × 12 mm unit area. The thickness of a mode-R sensing material (graphene nanoplatelets) and mode-C dielectric (the mixture of carbon black and silicone rubber) is 1 mm and 2.5 mm, respectively; (3) for mode-R, the linearity of temperature-resistance curve can achieve 0.998 in the temperature range from 25°C to 65°C. And for mode-C, various materials can be successfully detected with fast response and high reversibility. Meanwhile, the study compensated the influence of object temperature to ensure mode-C properly works. A cooperative sensing test shows that R-C dual modes sense effectively which can enlarge the sensing distance compared with the single mode proximity sensor. The fabrication of this sensor is convenient, and the integrity of a flexible sandwich-like structure based on dual modes is beneficial to form arrays, which is suitable to be used in skin-like sensing applications.

LOPUT Laser: A novel concept to realize single longitudinal mode ...

Indian Academy of Sciences (India)

2014-02-05

Feb 5, 2014 ... Abstract. We propose a novel type of cavity design to generate single longitudinal mode laser known as LOPUT cavity. LOPUT cavity stands for linear orthogonally polarized modes resulting in unidirectional travelling wave cavity. The technique can be applied to both isotropic as well as anisotropic gain ...

An overmoded relativistic backward wave oscillator with efficient dual-mode operation

International Nuclear Information System (INIS)

Xiao, Renzhen; Li, Jiawei; Bai, Xianchen; Song, Zhimin; Teng, Yan; Ye, Hu; Li, Xiaoze; Sun, Jun; Chen, Changhua; Zhang, Xiaowei

2014-01-01

A dual-mode operation mechanism in an overmoded relativistic backward wave oscillator is presented. The electron beam interacts with the −1st space harmonic of TM 01 mode synchronously in the slow wave structure. Then the backward propagating TM 01 mode is converted to the forward propagating TM 02 mode. As the phase velocity of the volume harmonic of TM 02 mode is about twice that of the surface harmonic of TM 01 mode, the TM 02 mode also plays an important role in the high-power microwave generation. Particle-in-cell simulation shows that an efficiency of 48% and a significant improvement of the power capacity have been obtained

Development and Use of the Dual-Mode Plasma Torch

International Nuclear Information System (INIS)

Womack, R.; Shuey, M.

2002-01-01

After several years of development, a commercially available high-temperature treatment system has been developed and installed that treats heterogeneous low-level radioactive waste. High temperature plasma processing, unique torch design and operating features make it feasible to achieve a volume reduced, permanent, high integrity waste form while eliminating the personnel exposure and costs associated with conventional sorting, characterizing and handling. Plasma technology can also be used to treat previous conditioned waste packages that no longer meet the current acceptance criteria for final disposal. Plasma treatment can result, in many cases, in a substantial volume reduction, which lowers the final disposal costs. This paper covers the recently patented dual mode plasma torch design(1), the lessons learned that fostered its development and the advantages it brings to radioactive waste processing. This paper also provides current full scale Plasma Arc Centrifugal Treatment (PACT) project status and how the dual mode torch is being used in the PACT system

Subterahertz Longitudinal Phonon Modes Propagating in a Lipid Bilayer Immersed in an Aqueous Medium

Science.gov (United States)

Zakhvataev, V. E.

2018-04-01

The properties of subterahertz longitudinal acoustic phonon modes in the hydrophobic region of a lipid bilayer immersed in a compressible viscous aqueous medium are investigated theoretically. An approximate expression is obtained for the Mandelstam-Brillouin components of the dynamic structure factor of a bilayer. The analysis is based on a generalized hydrodynamic model of the "two-dimensional lipid bilayer + three-dimensional fluid medium" system, as well as on known sharp estimates for the frequencies and lifetimes of long-wavelength longitudinal acoustic phonons in a free hydrated lipid bilayer and in water, obtained from inelastic X-ray scattering experiments and molecular dynamics simulations. It is shown that, for characteristic values of the parameters of the membrane system, subterahertz longitudinal phonon-like excitations in the hydrophobic part of the bilayer are underdamped. In this case, the contribution of the viscous flow of the aqueous medium to the damping of a longitudinal membrane mode is small compared with the contribution of the lipid bilayer. Quantitative estimates of the damping ratio agree well with the experimental results for the vibration mode of the enzyme lysozyme in aqueous solution [1]. It is also shown that a coupling between longitudinal phonon modes of the bilayer and relaxation processes in its fluid environment gives rise to an additional peak in the scattering spectrum, which corresponds to a non-propagating mode.

Examining Policy Guidelines for Distance Education in Dual Mode ...

African Journals Online (AJOL)

The study reports a case of distance education policy in the Kwame Nkrumah University of Science and Technology (KNUST), a dual mode University in Ghana. The interview method was used to obtain information from 21 purposively selected key informants in the University. Policy documents that addressed Distance ...

Longitudinal Losses Due to Breathing Mode Excitation in Radiofrequency Linear Accelerators

OpenAIRE

Channell, Paul J.

2010-01-01

Transverse breathing mode oscillations in a particle beam can couple energy into longitudinal oscillations in a bunch of finite length and cause significant losses. We develop a model that illustrates this effect and explore the dependence on mismatch size, space-charge tune depression, longitudinal focusing strength, bunch length, and RF bucket length.

Design and analysis of a dual mode CMOS field programmable analog array

International Nuclear Information System (INIS)

Cheng Xiaoyan; Yang Haigang; Yin Tao; Wu Qisong; Zhang Hongfeng; Liu Fei

2014-01-01

This paper presents a novel field-programmable analog array (FPAA) architecture featuring a dual mode including discrete-time (DT) and continuous-time (CT) operation modes, along with a highly routable connection boxes (CBs) based interconnection lattice. The dual mode circuit for the FPAA is capable of achieving targeted optimal performance in different applications. The architecture utilizes routing switches in a CB not only for the signal interconnection purpose but also for control of the electrical charge transfer required in switched-capacitor circuits. This way, the performance of the circuit in either mode shall not be hampered with adding of programmability. The proposed FPAA is designed and implemented in a 0.18 μm standard CMOS process with a 3.3 V supply voltage. The result from post-layout simulation shows that a maximum bandwidth of 265 MHz through the interconnection network is achieved. The measured results from demonstrated examples show that the maximum signal bandwidth of up to 2 MHz in CT mode is obtained with the spurious free dynamic range of 54 dB, while the signal processing precision in DT mode reaches 96.4%. (semiconductor integrated circuits)

Fluid dynamics, cavitation, and tip-to-tissue interaction of longitudinal and torsional ultrasound modes during phacoemulsification.

Science.gov (United States)

Zacharias, Jaime; Ohl, Claus-Dieter

2013-04-01

To describe the fluidic events that occur in a test chamber during phacoemulsification with longitudinal and torsional ultrasound (US) modalities. Pasteur Ophthalmic Clinic Phacodynamics Laboratory, Santiago, Chile, and Nanyang Technological University, Singapore. Experimental study. Ultra-high-speed videos of a phacoemulsifying tip were recorded while the tip operated in longitudinal and torsional US modalities using variable US power. Two high-speed video cameras were used to record videos up to 625,000 frames per second. A high-intensity spotlight source was used for illumination to engage shadowgraphy techniques. Particle image velocimetry was used to evaluate fluidic patterns while a hyperbaric environmental system allowed the evaluation of cavitation effects. Tip-to-tissue interaction at high speed was evaluated using human cataract fragments. Particle imaging velocimetry showed the following flow patterns for longitudinal and torsional modes at high US powers: forward-directed streaming with longitudinal mode and backward-directed streaming with torsional mode. The ultrasound power threshold for the appearance of cavitation was 60% for longitudinal mode and 80% for torsional mode. Cavitation was suppressed with pressure of 1.0 bar for longitudinal mode and 0.3 bar for torsional mode. Generation of previously unseen stable gaseous microbubbles was noted. Tip-to-tissue interaction analysis showed the presence of cavitation bubbles close to the site of fragmentation with no apparent effect on cutting. High-speed imaging and particle image velocimetry yielded a better understanding and differentiated the fluidic pattern behavior between longitudinal and torsional US during phacoemulsification. These recordings also showed more detailed aspects of cavitation that clarified its role in lens material cutting for both modalities. Copyright © 2013 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Longitudinal Modes along Thin Piezoelectric Waveguides for Liquid Sensing Applications

Directory of Open Access Journals (Sweden)

Cinzia Caliendo

2015-06-01

Full Text Available The propagation of longitudinally polarized acoustic modes along thin piezoelectric plates (BN, ZnO, InN, AlN and GaN is theoretically studied, aiming at the design of high frequency electroacoustic devices suitable for work in liquid environments. The investigation of the acoustic field profile across the plate revealed the presence of longitudinally polarized Lamb modes, travelling at velocities close to that of the longitudinal bulk acoustic wave propagating in the same direction. Such waves are suitable for the implementation of high-frequency, low-loss electroacoustic devices operating in liquid environments. The time-averaged power flow density, the phase velocity and the electroacoustic coupling coefficient K2 dispersion curves were studied, for the first (S0 and four higher order (S1, S2, S3, S4 symmetrical modes for different electrical boundary conditions. Two electroacoustic coupling configurations were investigated, based on interdigitated transducers, with or without a metal floating electrode at the opposite plate surface. Enhanced performances, such as a K2 as high as 8.5% and a phase velocity as high as 16,700 m/s, were demostrated for the ZnO- and BN-based waveguides, as an example. The relative velocity changes, and the inertial and viscous sensitivities of the first symmetric and anti-symmetric mode, S0 and A0, propagating along thin plates bordered by a viscous liquid were derived using the perturbation approach. The present study highlights the feasibility of the piezoelectric waveguides to the development of high-frequency, integrated-circuits compatible electroacoustic devices suitable for working in liquid environment.

Dual fuel mode operation in diesel engines using renewable fuels: Rubber seed oil and coir-pith producer gas

Energy Technology Data Exchange (ETDEWEB)

Ramadhas, A.S.; Jayaraj, S.; Muraleedharan, C. [Department of Mechanical Engineering, National Institute of Technology Calicut, Calicut-673601 (India)

2008-09-15

Partial combustion of biomass in the gasifier generates producer gas that can be used as supplementary or sole fuel for internal combustion engines. Dual fuel mode operation using coir-pith derived producer gas and rubber seed oil as pilot fuel was analyzed for various producer gas-air flow ratios and at different load conditions. The engine is experimentally optimized with respect to maximum pilot fuel savings in the dual fuel mode operation. The performance and emission characteristics of the dual fuel engine are compared with that of diesel engine at different load conditions. Specific energy consumption in the dual-fuel mode of operation with oil-coir-pith operation is found to be in the higher side at all load conditions. Exhaust emission was found to be higher in the case of dual fuel mode of operation as compared to neat diesel/oil operation. Engine performance characteristics are inferior in fully renewable fueled engine operation but it suitable for stationary engine application, particularly power generation. (author)

SPHERICAL COVERAGE DUAL MODE SENSOR FOR UAS SEPARATION ASSURANCE, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Proposed is a dual-mode sensor for use aboard unmanned aircraft for safe operation in the NAS that: 1. Incorporates high resolution Millimeter Wave radar with high...

Radio frequency ablation in the rabbit lung using wet electrodes: comparison of monopolar and dual bipolar electrode mode

International Nuclear Information System (INIS)

Jin, Gong Yong; Park, Sang Hee; Han, Young Min; Chung, Gyung Ho; Kwak, Hyo Sung; Jeon, Soo Bin; Lee, Yong Chul

2006-01-01

To compare the effect of radio frequency ablation (RFA) on the dimensions of radio frequency coagulation necrosis in a rabbit lung using a wet electrode in monopolar mode with that in dual electrode bipolar mode at different infusion rates (15 mm/hr versus 30 ml/hr) and saline concentrations (0.9% normal versus 5.8% hypertonic saline. Fifty ablation zones (one ablation zone in each rabbit) were produced in 50 rabbit using one or two 16-guage wet electrodes with a 1- cm active tip. The RFA system used in the monopolar and dual electrode wet bipolar RFA consisted of a 375-kHz generator (Elektrotom HiTT 106, Berchtold, Medizinelektronik, Germany). The power used was 30 watts and the exposure time was 5 minutes. The rabbits were assigned to one of five groups. Group A (n = 10) was infused with 0.9% NaCl used at a rate of 30 ml/hr in a monopolar mode. Groups B (n=10) and C (n=10) were infused with 0.9% NaCl at a rate of 15 and 30ml/hr, respectively in dual electrode bipolar mode; groups D (n=10) and E (n=10) were infused with 5.8% NaCl at a rate of 15 and 30 ml/hr, respectively in a dual electrode bipolar mode. The dimensions of the ablation zones in the gross specimens from the groups were compared using one-way analysis of variance by means of the Scheffe test (post-hoc testing). The mean largest diameter of the ablation zones was larger in dual electrode bipolar mode (30.9 ± 4.4 mm) than in monopolar mode (22.5 ± 3.5 mm). The mean smallest diameter of the ablation zones was larger in dual electrode bipolar mode (22.3 ± 2.5 mm) than in monopolar mode (19.5 ± 3.5 mm). There were significant differences in the largest and smallest dimension between the monopolar (group A ) ana dual electrode wet bipolar mode (groups B-E). In dual electrode bipolar mode, the mean largest diameter of the ablation zones was larger at an infusion rate of 15 ml/hr (34.2 ± 4.0 mm) than at 30 ml/hr (27.6 ± 0.0 mm), and the mean smallest diameter of the ablation zones was larger at an

Detecting mode hopping in single-longitudinal-mode fiber ring lasers based on an unbalanced fiber Michelson interferometer.

Science.gov (United States)

Ma, Mingxiang; Hu, Zhengliang; Xu, Pan; Wang, Wei; Hu, Yongming

2012-10-20

A method of detecting mode hopping for single-longitudinal-mode (SLM) fiber ring lasers has been proposed and experimentally demonstrated. The method that is based on an unbalanced Michelson interferometer (MI) utilizing phase generated carrier modulation instantly transforms mode-hopping dynamics into steep phase changes of the interferometer. Multiform mode hops in an SLM erbium-doped fiber ring laser with an 18.6 MHz mode spacing have been detected exactly in real-time domain and discussed in detail. Numerical results show that the MI-based method has a high testing sensitivity for identifying mode hopping, which will play a significant role in evaluating the output stability of SLM fiber lasers.

Tunable and switchable dual-wavelength passively mode-locked Bi-doped all-fiber ring laser based on nonlinear polarization rotation

International Nuclear Information System (INIS)

Luo, A-P; Luo, Z-C; Xu, W-C; Dvoyrin, V V; Mashinsky, V M; Dianov, E M

2011-01-01

We demonstrate a tunable and switchable dual-wavelength passively mode-locked Bi-doped all-fiber ring laser by using nonlinear polarization rotation (NPR) technique. Exploiting the spectral filtering effect caused by the combination of the polarizer and intracavity birefringence, the wavelength separation of dual-wavelength mode-locked pulses can be flexibly tuned between 2.38 and 20.45 nm. Taking the advantage of NPR-induced intensity-dependent loss to suppress the mode competition, the stable dual-wavelength pulses output is obtained at room temperature. Moreover, the dual-wavelength switchable operation is achieved by simply rotating the polarization controllers (PCs)

Design and optimisation of dual-mode heat pump systems using natural fluids

International Nuclear Information System (INIS)

Zhang Wenling; Klemeš, Jiří Jaromír; Kim, Jin-Kuk

2012-01-01

The paper introduces new multi-period modelling and design methodology for dual-mode heat pumps using natural fluids. First, a mathematical model is developed to capture thermodynamic and operating characteristics of dual-mode heat pump systems, subject to different ambient temperatures. The multi-period optimisation framework has been developed to reflect different ambient conditions and its influences on heat pump performance, as well as to determine a system capacity of heat pump which allows systematic economic trade-offs between supplementary heating (or cooling) and operating cost for heat pump. Case study considering three geographical locations with different heating and cooling demands is presented to illustrate the importance of using multi-period optimisation for the design of heat pump systems.

Carbon Nanodots as Dual-Mode Nanosensors for Selective Detection of Hydrogen Peroxide

Science.gov (United States)

Shen, Cheng-Long; Su, Li-Xia; Zang, Jin-Hao; Li, Xin-Jian; Lou, Qing; Shan, Chong-Xin

2017-07-01

Hydrogen peroxide (H2O2) is an important product of oxidase-based enzymatic reactions, such as glucose/glucose oxidase (GOD) reaction. Therefore, the probing of generated H2O2 for achieving the detection of various carbohydrates and their oxidases is very significative. Herein, we report one kind of dual-emission carbon nanodots (CDs) that can serve as novel dual-mode nanosensors with both fluorometric and colorimetric output for the selective detection of H2O2. The dual-model nanosensors are established only by the undecorated dual-emission CDs, where significant fluorometric and colorimetric changes are observed with the addition of different concentrations of H2O2 in the CD solution, which benefit to the achievement of the naked-eye detection for H2O2. The mechanism of the nanosensors can be attributed to the fact that the external chemical stimuli like hydroxyl radicals from H2O2 bring about the change of surface properties and the aggregation of CDs, which dominate the emission and absorption of CDs. The constructed dual-mode nanosensors exhibit good biocompatibility and high selectivity toward H2O2 with a linear detection range spanning from 0.05 to 0.5 M and allow the detection of H2O2 as low as 14 mM.

Utilizing wheel-ring architecture for stable and selectable single-longitudinal-mode erbium fiber laser

Science.gov (United States)

Yeh, Chien-Hung; Yang, Zi-Qing; Huang, Tzu-Jung; Chow, Chi-Wai

2018-03-01

To achieve a steady single-longitudinal-mode (SLM) erbium-doped fiber (EDF) laser, the wheel-ring architecture is proposed in the laser cavity. According to Vernier effect, the proposed wheel-ring can produce three different free spectrum ranges (FSRs) to serve as the mode-filter for suppressing the densely multi-longitudinal-mode (MLM). Here, to complete wavelength-tunable EDF laser, an optical tunable bandpass filter (OTBF) is utilized inside the cavity for tuning arbitrarily. In addition, the entire output performances of the proposed EDF wheel-ring laser are also discussed and analyzed experimentally.

A dual-mode 6-9 GHz transmitter for OFDM-UWB

International Nuclear Information System (INIS)

Chen Yunfeng; Gao Ting; Li Wei; Li Ning; Ren Junyan

2011-01-01

This paper presents a fully integrated dual-mode 6 to 9 GHz transmitter for both WiMedia and China MB-OFDM UWB applications. The proposed transmitter consists of a dual-mode I/QLPF, an up-conversion mixer, a two-stage power driver amplifier and a broadband high-speed frequency divider with LO buffers for I/Q LO carrier generation. The measurement results show that the gain ripple of the transmitter is within ±1.5/±2.8 dB from 6 to 8.7/9 GHz. The output IP3 is about +13.2 dBm, the output 1dBCP is around +2.8 dBm, and the LO leakage/sideband rejection ratio is about -35/-38 dBc. The ESD protected chip is fabricated with a TSMC 0.13 μm RFCMOS process with a die size of 1.6 x 1.3 mm 2 and the core circuit consumes only 46 mA under a 1.2 V supply. (semiconductor integrated circuits)

A dual-mode 6-9 GHz transmitter for OFDM-UWB

Energy Technology Data Exchange (ETDEWEB)

Chen Yunfeng; Gao Ting; Li Wei; Li Ning; Ren Junyan, E-mail: jyren@fudan.edu.cn, E-mail: w-li@fudan.edu.cn [State Key Laboratory of ASIC and System, Fudan University, Shanghai 201203 (China)

2011-05-15

This paper presents a fully integrated dual-mode 6 to 9 GHz transmitter for both WiMedia and China MB-OFDM UWB applications. The proposed transmitter consists of a dual-mode I/QLPF, an up-conversion mixer, a two-stage power driver amplifier and a broadband high-speed frequency divider with LO buffers for I/Q LO carrier generation. The measurement results show that the gain ripple of the transmitter is within {+-}1.5/{+-}2.8 dB from 6 to 8.7/9 GHz. The output IP3 is about +13.2 dBm, the output 1dBCP is around +2.8 dBm, and the LO leakage/sideband rejection ratio is about -35/-38 dBc. The ESD protected chip is fabricated with a TSMC 0.13 {mu}m RFCMOS process with a die size of 1.6 x 1.3 mm{sup 2} and the core circuit consumes only 46 mA under a 1.2 V supply. (semiconductor integrated circuits)

Stability of higher-order longitudinal modes in a bunched beam without mode coupling

International Nuclear Information System (INIS)

Satoh, K.

1981-05-01

The theory of longitudinal instabilities of bunched beams was proposed by F. Sacherer. Starting from the Vlasov equation, he derived the integral equation for the perturbed distribution function. While the general method to solve the integral equation was given by Sacherer, a number of other papers discussing longitudinal bunched beam instability have also been published. Here we want to propose another formalism with which we can treat the integral equation without mode coupling for the case of a Gaussian bunch. We then generalize the formalism for the other bunch distributions, and derive a practical method to analyze the instability for the case of a parabolic bunch. While the solution of the Sacherer equation that we find is not new, we present another approach to solve it. Since the integral equation for the transverse instability is similar to that for the longitudinal instability, this formalism is also useful for the transverse case. 12 figs., 4 figs

Modulating Brain Connectivity by Simultaneous Dual-Mode Stimulation over Bilateral Primary Motor Cortices in Subacute Stroke Patients

Directory of Open Access Journals (Sweden)

Jungsoo Lee

2018-01-01

Full Text Available Repetitive transcranial magnetic stimulation (rTMS or transcranial direct current stimulation (tDCS has been used for the modulation of stroke patients’ motor function. Recently, more challenging approaches have been studied. In this study, simultaneous stimulation using both rTMS and tDCS (dual-mode stimulation over bilateral primary motor cortices (M1s was investigated to compare its modulatory effects with single rTMS stimulation over the ipsilesional M1 in subacute stroke patients. Twenty-four patients participated; 12 participants were assigned to the dual-mode stimulation group while the other 12 participants were assigned to the rTMS-only group. We assessed each patient’s motor function using the Fugl-Meyer assessment score and acquired their resting-state fMRI data at two times: prior to stimulation and 2 months after stimulation. Twelve healthy subjects were also recruited as the control group. The interhemispheric connectivity of the contralesional M1, interhemispheric connectivity between bilateral hemispheres, and global efficiency of the motor network noticeably increased in the dual-mode stimulation group compared to the rTMS-only group. Contrary to the dual-mode stimulation group, there was no significant change in the rTMS-only group. These data suggested that simultaneous dual-mode stimulation contributed to the recovery of interhemispheric interaction than rTMS only in subacute stroke patients. This trial is registered with NCT03279640.

Research on FBG-based longitudinal-acousto-optic modulator with Fourier mode coupling method.

Science.gov (United States)

Li, Zhuoxuan; Pei, Li; Liu, Chao; Ning, Tigang; Yu, Shaowei

2012-10-20

Fourier mode coupling model was first applied to achieve the spectra property of a fiber Bragg grating (FBG)-based longitudinal-acousto-optic modulator. Compared with traditional analysis algorithms, such as the transfer matrix method, the Fourier mode coupling model could improve the computing efficiency up to 100 times with a guarantee of accuracy. In this paper, based on the theoretical analysis of this model, the spectra characteristics of the modulator in different frequencies and acoustically induced strains were numerically simulated. In the experiment, a uniform FBG was modulated by acoustic wave (AW) at 12 different frequencies. In particular, the modulator responses at 563 and 885.5 KHz with three different lead zirconate titanate (PZT) loads applied were plotted for illustration, and the linear fitting of experimental data demonstrated a good match with the simulation result. The acoustic excitation of the longitudinal wave is obtained using a conic silica horn attached to the surface of a shear-mode PZT plate paralleled to the fiber axis. This way of generating longitudinal AW with a transversal PZT may shed light on the optimal structural design for the FBG-based longitudinal-acousto-optic modulator.

Bioinspired Flexible and Highly Responsive Dual-Mode Strain/Magnetism Composite Sensor.

Science.gov (United States)

Huang, Pei; Li, Yuan-Qing; Yu, Xiao-Guang; Zhu, Wei-Bin; Nie, Shu-Yan; Zhang, Hao; Liu, Jin-Rui; Hu, Ning; Fu, Shao-Yun

2018-04-04

The mimicry of human skin to detect both oncoming and physical-contacting object is of great importance in the fields of manufacturing, artificial robots and vehicles, etc. Herein, a novel bioinspired flexible and highly responsive dual-mode strain/magnetism composite sensor, which works via both contact and contactless modes, is first fabricated by incorporating Fe 3 O 4 /silicone system into a carbon fiber aerogel (CFA). The distance dependence of magnetic field endorses the CFA/Fe 3 O 4 /silicone composite possible for spatial sensing due to the introduction of Fe 3 O 4 magnetic nanoparticles. As a result, the as-prepared flexible sensor exhibits precise and real-time response not only to direct-contact compression as usual but also to contactless magnetic field in a wide frequency range from 0.1 to 10 Hz, achieving the maximum variance of 68% and 86% in relative electrical resistance, respectively. The contact and contactless sensing modes of the strain/magnetism sensor are clearly demonstrated by recording the speeds of bicycle riding and walking, respectively. Interestingly, this dual-mode composite sensor exhibits the capacity of identifying the contact and contactless state, which is the first report for flexible sensors. The current protocol is eco-friendly, facile, and thought-provoking for the fabrication of multifunctional sensors.

A Dual-Mode Large-Arrayed CMOS ISFET Sensor for Accurate and High-Throughput pH Sensing in Biomedical Diagnosis.

Science.gov (United States)

Huang, Xiwei; Yu, Hao; Liu, Xu; Jiang, Yu; Yan, Mei; Wu, Dongping

2015-09-01

The existing ISFET-based DNA sequencing detects hydrogen ions released during the polymerization of DNA strands on microbeads, which are scattered into microwell array above the ISFET sensor with unknown distribution. However, false pH detection happens at empty microwells due to crosstalk from neighboring microbeads. In this paper, a dual-mode CMOS ISFET sensor is proposed to have accurate pH detection toward DNA sequencing. Dual-mode sensing, optical and chemical modes, is realized by integrating a CMOS image sensor (CIS) with ISFET pH sensor, and is fabricated in a standard 0.18-μm CIS process. With accurate determination of microbead physical locations with CIS pixel by contact imaging, the dual-mode sensor can correlate local pH for one DNA slice at one location-determined microbead, which can result in improved pH detection accuracy. Moreover, toward a high-throughput DNA sequencing, a correlated-double-sampling readout that supports large array for both modes is deployed to reduce pixel-to-pixel nonuniformity such as threshold voltage mismatch. The proposed CMOS dual-mode sensor is experimentally examined to show a well correlated pH map and optical image for microbeads with a pH sensitivity of 26.2 mV/pH, a fixed pattern noise (FPN) reduction from 4% to 0.3%, and a readout speed of 1200 frames/s. A dual-mode CMOS ISFET sensor with suppressed FPN for accurate large-arrayed pH sensing is proposed and demonstrated with state-of-the-art measured results toward accurate and high-throughput DNA sequencing. The developed dual-mode CMOS ISFET sensor has great potential for future personal genome diagnostics with high accuracy and low cost.

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.

Enhanced Two-Stage Hierarchical Control for a Dual Mode WECS-Based Microgrid

Directory of Open Access Journals (Sweden)

Rasool M. Imran

2018-05-01

Full Text Available Along with the great benefits of utilizing renewable energy (e.g., wind energy in the power system, there are also some issues, such as increasing the uncertainty and reducing the system inertia. Communication-based centralized control has started to play a significant role in reacting to the aforementioned issues, especially for relatively small systems, such as microgrids. In this context, in this paper, an enhanced communication-based hierarchical control for a dual mode wind energy conversion system-based microgrid is modeled and investigated. The primary stage utilized the P-V/Q-f droop method, which is the preferred droop method to be used in microgrids when the line impedance is mainly resistive. The secondary stage relied on an enhanced methodology for compensating the deviations of voltage and frequency and improving the performance of the microgrid during small and large signal disturbances. Moreover, as this microgrid operates in a dual mode, the mode transition cases from grid-tied mode to autonomous mode and vice versa have been addressed. Thereafter, an improved control scheme for the unplanned outage transition and a modified control scheme for the pre-synchronization and reconnection transition were proposed. Finally, the proposed work was evaluated by the simulation results in MATLAB environment.

Volatile organic compounds discrimination based on dual mode detection

Science.gov (United States)

Yu, Yuanyuan; Wu, Enxiu; Chen, Yan; Feng, Zhihong; Zheng, Shijun; Zhang, Hao; Pang, Wei; Liu, Jing; Zhang, Daihua

2018-06-01

We report on a volatile organic compound (VOC) sensor that can provide concentration-independent signals toward target gases. The device is based on a dual-mode detection mechanism that can simultaneously record the mechanical (resonant frequency, f r) and electrical (current, I) responses of the same gas adsorption event. The two independent signals form a unique I–f r trace for each target VOC as the concentration varies. The mechanical response (frequency shift, Δf r) resulting from mass load on the device is directly related to the amount of surface adsorptions, while the electrical response (current variation, ΔI) is associated with charge transfer across the sensing interface and changes in carrier mobility. The two responses resulting from independent physical processes reflect intrinsic physical properties of each target gas. The ΔI–Δf r trace combined with the concentration dependent frequency (or current) signals can therefore be used to achieve target both recognition and quantification. The dual-mode device is designed and fabricated using standard complementary metal oxide semiconductor (CMOS) compatible processes. It exhibits consistent and stable performance in our tests with six different VOCs including ethanol, methanol, acetone, formaldehyde, benzene and hexane.

Research on a Novel Exciting Method for a Sandwich Transducer Operating in Longitudinal-Bending Hybrid Modes

Directory of Open Access Journals (Sweden)

Yingxiang Liu

2017-06-01

Full Text Available A novel exciting method for a sandwich type piezoelectric transducer operating in longitudinal-bending hybrid vibration modes is proposed and discussed, in which the piezoelectric elements for the excitations of the longitudinal and bending vibrations share the same axial location, but correspond to different partitions. Whole-piece type piezoelectric plates with three separated partitions are used, in which the center partitions generate the first longitudinal vibration, while the upper and lower partitions produce the second bending vibration. Detailed comparisons between the proposed exciting method and the traditional one were accomplished by finite element method (FEM calculations, which were further verified by experiments. Compared with the traditional exciting method using independent longitudinal ceramics and bending ceramics, the proposed method achieves higher electromechanical coupling factors and larger vibration amplitudes, especially for the bending vibration mode. This novel exciting method for longitudinal-bending hybrid vibrations has not changed the structural dimensions of the sandwich transducer, but markedly improves the mechanical output ability, which makes it very helpful and meaningful in designing new piezoelectric actuators operated in longitudinal-bending hybrid vibration modes.

Measurement of flow fluctuations in single longitudinal mode pulsed ...

Indian Academy of Sciences (India)

2014-02-12

Feb 12, 2014 ... Page 1 ... Keywords. Dye lasers; single longitudinal mode; flow fluctuations. PACS Nos 42.55.Mv; 42.60.Mi; 42.60.By. 1. Introduction. Narrow-band dye lasers offer ... stabilized tunable laser source plays an important role for many applications as mentioned above [1]. For tight wavelength control, the ...

Dual-mode plasmonic nanorod type antenna based on the concept of a trapped dipole.

Science.gov (United States)

Panaretos, Anastasios H; Werner, Douglas H

2015-04-06

In this paper we theoretically investigate the feasibility of creating a dual-mode plasmonic nanorod antenna. The proposed design methodology relies on adapting to optical wavelengths the principles of operation of trapped dipole antennas, which have been widely used in the low MHz frequency range. This type of antenna typically employs parallel LC circuits, also referred to as "traps", which are connected along the two arms of the dipole. By judiciously choosing the resonant frequency of these traps, as well as their position along the arms of the dipole, it is feasible to excite the λ/2 resonance of both the original dipole as well as the shorter section defined by the length of wire between the two traps. This effectively enables the dipole antenna to have a dual-mode of operation. Our analysis reveals that the implementation of this concept at the nanoscale requires that two cylindrical pockets (i.e. loading volumes) be introduced along the length of the nanoantenna, inside which plasmonic core-shell particles are embedded. By properly selecting the geometry and constitution of the core-shell particle as well as the constitution of the host material of the two loading volumes and their position along the nanorod, the equivalent effect of a resonant parallel LC circuit can be realized. This effectively enables a dual-mode operation of the nanorod antenna. The proposed methodology introduces a compact approach for the realization of dual-mode optical sensors while at the same time it clearly illustrates the inherent tuning capabilities that core-shell particles can offer in a practical framework.

Dual-mode operation of 2D material-base hot electron transistors

KAUST Repository

Lan, Yann-Wen; Jr., Carlos M. Torres,; Zhu, Xiaodan; Qasem, Hussam; Adleman, James R.; Lerner, Mitchell B.; Tsai, Shin-Hung; Shi, Yumeng; Li, Lain-Jong; Yeh, Wen-Kuan; Wang, Kang L.

2016-01-01

Vertical hot electron transistors incorporating atomically-thin 2D materials, such as graphene or MoS2, in the base region have been proposed and demonstrated in the development of electronic and optoelectronic applications. To the best of our knowledge, all previous 2D material-base hot electron transistors only considered applying a positive collector-base potential (V-CB > 0) as is necessary for the typical unipolar hot-electron transistor behavior. Here we demonstrate a novel functionality, specifically a dual-mode operation, in our 2D material-base hot electron transistors (e.g. with either graphene or MoS2 in the base region) with the application of a negative collector-base potential (V-CB < 0). That is, our 2D material-base hot electron transistors can operate in either a hot-electron or a reverse-current dominating mode depending upon the particular polarity of VCB. Furthermore, these devices operate at room temperature and their current gains can be dynamically tuned by varying VCB. We anticipate our multi-functional dual-mode transistors will pave the way towards the realization of novel flexible 2D material-based high-density and low-energy hot-carrier electronic applications.

Dual-mode operation of 2D material-base hot electron transistors

KAUST Repository

Lan, Yann-Wen

2016-09-01

Vertical hot electron transistors incorporating atomically-thin 2D materials, such as graphene or MoS2, in the base region have been proposed and demonstrated in the development of electronic and optoelectronic applications. To the best of our knowledge, all previous 2D material-base hot electron transistors only considered applying a positive collector-base potential (V-CB > 0) as is necessary for the typical unipolar hot-electron transistor behavior. Here we demonstrate a novel functionality, specifically a dual-mode operation, in our 2D material-base hot electron transistors (e.g. with either graphene or MoS2 in the base region) with the application of a negative collector-base potential (V-CB < 0). That is, our 2D material-base hot electron transistors can operate in either a hot-electron or a reverse-current dominating mode depending upon the particular polarity of VCB. Furthermore, these devices operate at room temperature and their current gains can be dynamically tuned by varying VCB. We anticipate our multi-functional dual-mode transistors will pave the way towards the realization of novel flexible 2D material-based high-density and low-energy hot-carrier electronic applications.

Dual-mode operation of 2D material-base hot electron transistors.

Science.gov (United States)

Lan, Yann-Wen; Torres, Carlos M; Zhu, Xiaodan; Qasem, Hussam; Adleman, James R; Lerner, Mitchell B; Tsai, Shin-Hung; Shi, Yumeng; Li, Lain-Jong; Yeh, Wen-Kuan; Wang, Kang L

2016-09-01

Vertical hot electron transistors incorporating atomically-thin 2D materials, such as graphene or MoS2, in the base region have been proposed and demonstrated in the development of electronic and optoelectronic applications. To the best of our knowledge, all previous 2D material-base hot electron transistors only considered applying a positive collector-base potential (VCB > 0) as is necessary for the typical unipolar hot-electron transistor behavior. Here we demonstrate a novel functionality, specifically a dual-mode operation, in our 2D material-base hot electron transistors (e.g. with either graphene or MoS2 in the base region) with the application of a negative collector-base potential (VCB transistors can operate in either a hot-electron or a reverse-current dominating mode depending upon the particular polarity of VCB. Furthermore, these devices operate at room temperature and their current gains can be dynamically tuned by varying VCB. We anticipate our multi-functional dual-mode transistors will pave the way towards the realization of novel flexible 2D material-based high-density and low-energy hot-carrier electronic applications.

Sliding-Mode Control to Compensate PVT Variations in Dual Core Systems

NARCIS (Netherlands)

Pourshaghaghi, H.R.; Fatemi, S.H.; Pineda de Gyvez, J.

2012-01-01

In this paper, we present a novel robust sliding-mode controller for stabilizing supply voltage and clock frequency of dual core processors determined by dynamic voltage and frequency scaling (DVFS) methods in the presence of systematic and random variations. We show that maximum rejection for

Active power filter for harmonic compensation using a digital dual-mode-structure repetitive control approach

DEFF Research Database (Denmark)

Zou, Zhixiang; Wang, Zheng; Cheng, Ming

2012-01-01

This paper presents an digital dual-mode-structure repetitive control approach for the single-phase shunt active power filter (APF), which aims to enhance the tracking ability and eliminate arbitrary order harmonic. The proposed repetitive control scheme blends the characteristics of both odd......-harmonic repetitive control and even-harmonic repetitive control. Moreover, the convergence rate is faster than conventional repetitive controller. Additionally, the parameters have been designed and optimized for the dual-mode structure repetitive control to improve the performance of APF system. Experimental...

1.5 W high efficiency and tunable single-longitudinal-mode Ho:YLF ring laser based on Faraday effect.

Science.gov (United States)

Wu, Jing; Ju, Youlun; Dai, Tongyu; Yao, Baoquan; Wang, Yuezhu

2017-10-30

We demonstrated an efficient and tunable single-longitudinal-mode Ho:YLF ring laser based on Faraday effect for application to measure atmospheric carbon dioxide (CO 2 ). Single-longitudinal-mode power at 2051.65 nm achieved 528 mW with the slope efficiency of 39.5% and the M 2 factor of 1.07, and the tunable range of about 178 GHz was obtained by inserting a Fabry-Perot (F-P) etalon with the thickness of 0.5 mm. In addition, the maximum single-longitudinal-mode power reached 1.5 W with the injected power of 528 mW at 2051.65 nm by master oscillator power amplifier (MOPA) technique. High efficiency and tunable single-longitudinal-mode based on Faraday effect around 2 μm has not been reported yet to the best of our knowledge.

Longitudinal tire force estimation based on sliding mode observer

Energy Technology Data Exchange (ETDEWEB)

El Hadri, A.; Cadiou, J.C.; M' Sirdi, N.K. [Versailles Univ., Paris (France). Lab. de Robotique; Beurier, G.; Delanne, Y. [Lab. Central des Ponts, Centre de Nantes (France)

2001-07-01

This paper presents an estimation method for vehicle longitudinal dynamics, particularly the tractive/braking force. The estimation can be used to detect a critical driving situation to improve security. It can be used also in several vehicle control systems. The main characteristics of the vehicle longitudinal dynamics were taken into account in the model used to design an observer and computer simulations. The state variables are the angular wheel velocity, vehicle velocity and the longitudinal tire force. The proposed differential equation of the tractive/braking force is derived using the concept of relaxation length. The observer designed is based on the sliding mode approach using only the angular wheel velocity measurement. The proposed method of estimation is verified through a one-wheel simulation model with a ''Magic formula'' tire model. Simulations results show an excellent reconstruction of the tire force. (orig.)

A 380pW Dual Mode Optical Wake-up Receiver with Ambient Noise Cancellation.

Science.gov (United States)

Lim, Wootaek; Jang, Taekwang; Lee, Inhee; Kim, Hun-Seok; Sylvester, Dennis; Blaauw, David

2016-06-01

We present a sub-nW optical wake-up receiver for wireless sensor nodes. The wake-up receiver supports dual mode operation for both ultra-low standby power and high data rates, while canceling ambient in-band noise. In 0.18µm CMOS the receiver consumes 380pW in always-on wake-up mode and 28.1µW in fast RX mode at 250kbps.

A novel dual mode neutron-gamma imager

International Nuclear Information System (INIS)

Cooper, Robert Lee; Gerling, Mark; Brennan, James S.; Mascarenhas, Nicholas; Mrowka, Stanley; Marleau, Peter

2010-01-01

The Neutron Scatter Camera (NSC) can image fission sources and determine their energy spectra at distances of tens of meters and through significant thicknesses of intervening materials in relatively short times (1). We recently completed a 32 element scatter camera and will present recent advances made with this instrument. A novel capability for the scatter camera is dual mode imaging. In normal neutron imaging mode we identify and image neutron events using pulse shape discrimination (PSD) and time of flight in liquid scintillator. Similarly gamma rays are identified from Compton scatter in the front and rear planes for our segmented detector. Rather than reject these events, we show it is possible to construct a gamma-ray image by running the analysis in a 'Compton mode'. Instead of calculating the scattering angle by the kinematics of elastic scatters as is appropriate for neutron events, it can be found by the kinematics of Compton scatters. Our scatter camera has not been optimized as a Compton gamma-ray imager but is found to work reasonably. We studied imaging performance using a Cs137 source. We find that we are able to image the gamma source with reasonable fidelity. We are able to determine gamma energy after some reasonable assumptions. We will detail the various algorithms we have developed for gamma image reconstruction. We will outline areas for improvement, include additional results and compare neutron and gamma mode imaging.

Spectrally interleaved, comb-mode-resolved spectroscopy using swept dual terahertz combs.

Science.gov (United States)

Hsieh, Yi-Da; Iyonaga, Yuki; Sakaguchi, Yoshiyuki; Yokoyama, Shuko; Inaba, Hajime; Minoshima, Kaoru; Hindle, Francis; Araki, Tsutomu; Yasui, Takeshi

2014-01-22

Optical frequency combs are innovative tools for broadband spectroscopy because a series of comb modes can serve as frequency markers that are traceable to a microwave frequency standard. However, a mode distribution that is too discrete limits the spectral sampling interval to the mode frequency spacing even though individual mode linewidth is sufficiently narrow. Here, using a combination of a spectral interleaving and dual-comb spectroscopy in the terahertz (THz) region, we achieved a spectral sampling interval equal to the mode linewidth rather than the mode spacing. The spectrally interleaved THz comb was realized by sweeping the laser repetition frequency and interleaving additional frequency marks. In low-pressure gas spectroscopy, we achieved an improved spectral sampling density of 2.5 MHz and enhanced spectral accuracy of 8.39 × 10(-7) in the THz region. The proposed method is a powerful tool for simultaneously achieving high resolution, high accuracy, and broad spectral coverage in THz spectroscopy.

Spectrally interleaved, comb-mode-resolved spectroscopy using swept dual terahertz combs

Science.gov (United States)

Hsieh, Yi-Da; Iyonaga, Yuki; Sakaguchi, Yoshiyuki; Yokoyama, Shuko; Inaba, Hajime; Minoshima, Kaoru; Hindle, Francis; Araki, Tsutomu; Yasui, Takeshi

2014-01-01

Optical frequency combs are innovative tools for broadband spectroscopy because a series of comb modes can serve as frequency markers that are traceable to a microwave frequency standard. However, a mode distribution that is too discrete limits the spectral sampling interval to the mode frequency spacing even though individual mode linewidth is sufficiently narrow. Here, using a combination of a spectral interleaving and dual-comb spectroscopy in the terahertz (THz) region, we achieved a spectral sampling interval equal to the mode linewidth rather than the mode spacing. The spectrally interleaved THz comb was realized by sweeping the laser repetition frequency and interleaving additional frequency marks. In low-pressure gas spectroscopy, we achieved an improved spectral sampling density of 2.5 MHz and enhanced spectral accuracy of 8.39 × 10-7 in the THz region. The proposed method is a powerful tool for simultaneously achieving high resolution, high accuracy, and broad spectral coverage in THz spectroscopy.

Dual Z-Source Inverter With Three-Level Reduced Common-Mode Switching

DEFF Research Database (Denmark)

Gao, Feng; Loh, Poh Chiang; Blaabjerg, Frede

2007-01-01

This paper presents the design of a dual Z-source inverter that can be used with either a single dc source or two isolated dc sources. Unlike traditional inverters, the integration of a properly designed Z-source network and semiconductor switches to the proposed dual inverter allows buck......-boost power conversion to be performed over a wide modulation range, with three-level output waveforms generated. The connection of an additional transformer to the inverter ac output also allows all generic wye-or delta-connected loads with three-wire or four-wire configuration to be supplied by the inverter....... Modulationwise, the dual inverter can be controlled using a carefully designed carrier-based pulsewidth-modulation (PWM) scheme that will always ensure balanced voltage boosting of the Z-source network while simultaneously achieving reduced common-mode switching. Because of the omission of dead-time delays...

Observation of transverse and longitudinal modes in non-neutral electron clouds confined in a magnetic mirror

International Nuclear Information System (INIS)

Eckhouse, S.; Fisher, A.; Rostoker, N.

1979-01-01

Electrostatic modes on non-neutral electron clouds confined in a magnetic mirror field have been investigated. The cloud contains 2 x 10 11 electrons at an average kinetic energy of 0.3 MeV for a magnetic field with a peak intensity of 9 kG at the midplane. It was found that the cloud is moving azimuthally as well as longitudinally. The azimuthal motion has an m=1 spatial nature. The longitudinal modes have a more complicated nature, but their frequency equals that of the azimuthal mode

Mode switching control of dual-evaporator air-conditioning systems

International Nuclear Information System (INIS)

Lin, J.-L.; Yeh, T.-J.

2009-01-01

Modern air-conditioners incorporate variable-speed compressors and variable-opening expansion valves as the actuators for improving cooling performance and energy efficiency. These actuators have to be properly feedback-controlled; otherwise the systems may exhibit even poorer performance than the conventional machines which use fixed-speed compressors and mechanical expansion valves. Particularly for an air-conditioner with multiple evaporators, there are occasions that the machine is operated in a mode that only selected evaporator(s) is(are) turned on, and switching(s) between modes occurs(occur) during the control process. In this case, one needs to have more carefully designed control and switching strategies to ensure the system performance. In this paper, a framework for mode switching control of the dual-evaporator air-conditioning (DEAC) system is proposed. The framework is basically an integration of a controller and a dynamic compensator. The controller, which possesses the flow-distribution capability and assumes both evaporators are on throughout the control process, is intended to provide nominal performance. While mode switching is achieved by varying the reference settings in the controller, the dynamic compensator is used to improve the transient responses immediately after the switching. Experiments indicate that the proposed framework can achieve satisfactory indoor temperature regulation and provide bumpless switching between different modes of operation.

A reconfigurable frequency-selective surface for dual-mode multi-band filtering applications

Science.gov (United States)

Majidzadeh, Maryam; Ghobadi, Changiz; Nourinia, Javad

2017-03-01

A reconfigurable single-layer frequency-selective surface (FSS) with dual-mode multi-band modes of operation is presented. The proposed structure is printed on a compact 10 × 10 mm2 FR4 substrate with the thickness of 1.6 mm. A simple square loop is printed on the front side while another one along with two defected vertical arms is deployed on the backside. To realise the reconfiguration, two pin diodes are embedded on the backside square loop. Suitable insertion of conductive elements along with pin diodes yields in dual-mode multi-band rejection of applicable in service frequency ranges. The first operating mode due to diodes' 'ON' state provides rejection of 2.4 GHz WLAN in 2-3 GHz, 5.2/5.8 GHz WLAN and X band in 5-12 GHz, and a part of Ku band in 13.9-16 GHz. In diodes 'OFF' state, the FSS blocks WLAN in 4-7.3 GHz, X band in 8-12.7 GHz as well as part of Ku band in 13.7-16.7 GHz. As well, high attenuation of incident waves is observed by a high shielding effectiveness (SE) in the blocked frequency bands. Also, a stable behaviour against different polarisations and angles of incidence is obtained. Comprehensive studies are conducted on a fabricated prototype to assess its performance from which encouraging results are obtained.

Pricing Models for Dual-channel Reverse Supply Chain Considering Regional Differences under “Internet Recycling” Mode in China

Science.gov (United States)

Wu, Di; Li, Peng; Chen, Juhong

2018-01-01

In recent years, the Internet technology has been deeply influencing recycling industry to make it more intelligent and interconnected. However, most existing papers on “Internet Recycling” neglected the problem of pricing strategy under online and offline channels for different levels of recyclers. Moreover, the effect of regional differences has been emphasized a lot in dual-channel forward supply chain, but recycling field has seldom been concerned about it. In this paper, a recycling system consisting of one recycling center and several third-party recyclers (TPR) was investigated based on traditional mode and dual-channel mode. The dual-channel reverse supply chain model is transformed from traditional mode by the introduction of online channel. It involves two recycling modes, as recycling centre for online recovery and “Recycling center+TPR” for offline recovery. By establishing pricing strategies based on Stackelberg game model, the impacts of regional differences were analysed. Finally, numerical analysis was given to illustrate the effectiveness of the pricing mechanisms and strategies.

Automotive dual-mode hydrogen generation system

Science.gov (United States)

Kelly, D. A.

The automotive dual mode hydrogen generation system is advocated as a supplementary hydrogen fuel means along with the current metallic hydride hydrogen storage method for vehicles. This system consists of utilizing conventional electrolysis cells with the low voltage dc electrical power supplied by two electrical generating sources within the vehicle. Since the automobile engine exhaust manifold(s) are presently an untapped useful source of thermal energy, they can be employed as the heat source for a simple heat engine/generator arrangement. The second, and minor electrical generating means consists of multiple, miniature air disk generators which are mounted directly under the vehicle's hood and at other convenient locations within the engine compartment. The air disk generators are revolved at a speed which is proportionate to the vehicles forward speed and do not impose a drag on the vehicles motion.

Feedback stabilization system for pulsed single longitudinal mode tunable lasers

Science.gov (United States)

Esherick, Peter; Raymond, Thomas D.

1991-10-01

A feedback stabilization system for pulse single longitudinal mode tunable lasers having an excited laser medium contained within an adjustable length cavity and producing a laser beam through the use of an internal dispersive element, including detection of angular deviation in the output laser beam resulting from detuning between the cavity mode frequency and the passband of the internal dispersive element, and generating an error signal based thereon. The error signal can be integrated and amplified and then applied as a correcting signal to a piezoelectric transducer mounted on a mirror of the laser cavity for controlling the cavity length.

High-efficiency dual-modes vortex beam generator with polarization-dependent transmission and reflection properties.

Science.gov (United States)

Tang, Shiwei; Cai, Tong; Wang, Guang-Ming; Liang, Jian-Gang; Li, Xike; Yu, Jiancheng

2018-04-23

Vortex beam is believed to be an effective way to extend communication capacity, but available efforts suffer from the issues of complex configurations, fixed operation mode as well as low efficiency. Here, we propose a general strategy to design dual-modes vortex beam generator by using metasurfaces with polarization-dependent transmission and reflection properties. Combining the focusing and vortex functionalities, we design/fabricate a type of compact dual-modes vortex beam generator operating at both reflection/transmission sides of the system. Experimental results demonstrate that the designed metadevice can switch freely and independently between the reflective vortex with topological charge m 1  = 2 and transmissive vortex with m 2  = 1. Moreover, the metadevice exhibits very high efficiencies of 91% and 85% for the reflective and transmissive case respectively. Our findings open a door for multifunctional metadevices with high performances, which indicate wide applications in modern integration-optics and wireless communication systems.

Unidirectional, dual-comb lasing under multiple pulse formation mechanisms in a passively mode-locked fiber ring laser

Science.gov (United States)

Liu, Ya; Zhao, Xin; Hu, Guoqing; Li, Cui; Zhao, Bofeng; Zheng, Zheng

2016-09-01

Dual-comb lasers from which asynchronous ultrashort pulses can be simultaneously generated have recently become an interesting research subject. They could be an intriguing alternative to the current dual-laser optical-frequency-comb source with highly sophisticated electronic control systems. If generated through a common light path traveled by all pulses, the common-mode noises between the spectral lines of different pulse trains could be significantly reduced. Therefore, coherent dual-comb generation from a completely common-path, unidirectional lasing cavity would be an interesting territory to explore. In this paper, we demonstrate such a dual-comb lasing scheme based on a nanomaterial saturable absorber with additional pulse narrowing and broadening mechanisms concurrently introduced into a mode-locked fiber laser. The interactions between multiple soliton formation mechanisms result in unusual bifurcation into two-pulse states with quite different characteristics. Simultaneous oscillation of pulses with four-fold difference in pulsewidths and tens of Hz repetition rate difference is observed. The coherence between these spectral-overlapped, picosecond and femtosecond pulses is further verified by the corresponding asynchronous cross-sampling and dual-comb spectroscopy measurements.

Dual Rotating Rake Measurements of Higher-Order Duct Modes: Validation Using Experimental and Numerical Data

Science.gov (United States)

Dahl, Milo D.; Hixon, Duane R.; Sutliff, Daniel L.

2018-01-01

A rotating rake mode measurement system was designed to measure acoustic duct modes generated by a fan stage. After analysis of the measured data, the mode coefficient amplitudes and phases were quantified. Early studies using this system found that mode power levels computed from rotating rake measured data would agree with the far-field power levels. However, this agreement required that the sound from the noise sources within the duct propagated outward from the duct exit without reflection and previous studies suggested conditions could exist where significant reflections could occur. This paper shows that mounting a second rake to the rotating system, with an offset in both the axial and the azimuthal directions, measures the data necessary to determine the modes propagating in both directions within a duct. The rotating rake data analysis technique was extended to include the data measured by the second rake. The analysis resulted in a set of circumferential mode coefficients at each of the two rake microphone locations. Radial basis functions were then least-squares fit to this data to obtain the radial mode coefficients for the modes propagating in both directions within the duct while accounting for the presence of evanescent modes. The validation of the dual-rotating-rake measurements was conducted using data from a combination of experiments and numerical calculations to compute reflection coefficients and other mode coefficient ratios. Compared to results from analytical and numerical computations, the results from dual-rotating-rake measured data followed the expected trends when frequency, mode number, and duct termination geometry were changed.

An effort to enhance hydrogen energy share in a compression ignition engine under dual-fuel mode using low temperature combustion strategies

International Nuclear Information System (INIS)

Chintala, V.; Subramanian, K.A.

2015-01-01

Highlights: • H 2 energy share increased from 18% with DDM to 36% with WDM (water injection). • H 2 energy share improved marginally with retarded injection timing mode (RDM). • Energy efficiency increased with increasing amount of H 2 in dual-fuel engine. • NO x emission decreased with water injection and retarded pilot fuel injection. • HC, CO and smoke emissions increased slightly with low temperature combustion. - Abstract: A limited hydrogen (H 2 ) energy share due to knocking is the major hurdle for effective utilization of H 2 in compression ignition (CI) engines under dual-fuel operation. The present study aims at improvement of H 2 energy share in a 7.4 kW direct injection CI engine under dual-fuel mode with two low temperature combustion (LTC) strategies; (i) retarded pilot fuel injection timing and (ii) water injection. Experiments were carried out under conventional strategies of diesel dual-fuel mode (DDM) and B20 dual-fuel mode (BDM); and LTC strategies of retarded injection timing dual-fuel mode (RDM) and water injected dual-fuel mode (WDM). The results explored that the H 2 energy share increased significantly from 18% with conventional DDM to 24, and 36% with RDM, and WDM respectively. The energy efficiency increased with increasing H 2 energy share under dual-fuel operation; however, for a particular energy share of 18% H 2 , it decreased from 34.8% with DDM to 33.7% with BDM, 32.7% with WDM and 29.9% with RDM. At 18% H 2 energy share, oxides of nitrogen emission decreased by 37% with RDM and 32% with WDM as compared to conventional DDM due to reduction of in-cylinder temperature, while it increased slightly about 5% with BDM. It is emerged from the study that water injection technique is the viable option among all other strategies to enhance the H 2 energy share in the engine with a slight penalty of increase in smoke, hydrocarbon, and carbon monoxide emissions

Tunable single and dual mode operation of an external cavity quantum-dot injection laser

International Nuclear Information System (INIS)

Biebersdorf, A; Lingk, C; De Giorgi, M; Feldmann, J; Sacher, J; Arzberger, M; Ulbrich, C; Boehm, G; Amann, M-C; Abstreiter, G

2003-01-01

We investigate quantum-dot (QD) lasers in an external cavity using Littrow and Littman configurations. Here, we report on a continuously tunable QD laser with a broad tuning range from 1047 to 1130 nm with high stability and efficient side mode suppression. The full-width at half-maximum of the laser line is 0.85 nm determined mainly by the quality of the external grating. This laser can be operated in a dual-mode modus, where the mode-spacing can be tuned continuously between 1.1 and 34 nm. Simultaneous emission of the two laser modes is shown by sum frequency generation experiments

Remote heterodyne millimeter-wave over fiber based OFDM-PON with master-to-slave injected dual-mode colorless FPLD pair.

Science.gov (United States)

Chen, Hsiang-Yu; Chi, Yu-Chieh; Lin, Gong-Ru

2015-08-24

A remote heterodyne millimeter-wave (MMW) carrier at 47.7 GHz over fiber synthesized with the master-to-slave injected dual-mode colorless FPLD pair is proposed, which enables the future connection between the wired fiber-optic 64-QAM OFDM-PON at 24 Gb/s with the MMW 4-QAM OFDM wireless network at 2 Gb/s. Both the single- and dual-mode master-to-slave injection-locked colorless FPLD pairs are compared to optimize the proposed 64-QAM OFDM-PON. For the unamplified single-mode master, the slave colorless FPLD successfully performs the 64-QAM OFDM data at 24 Gb/s with EVM, SNR and BER of 8.5%, 21.5 dB and 2.9 × 10(-3), respectively. In contrast, the dual-mode master-to-slave injection-locked colorless FPLD pair with amplified and unfiltered master can transmit 64-QAM OFDM data at 18 Gb/s over 25-km SMF to provide EVM, SNR and BER of 8.2%, 21.8 dB and 2.2 × 10(-3), respectively. For the dual-mode master-to-slave injection-locked colorless FPLD pair, even though the modal dispersion occurred during 25-km SMF transmission makes it sacrifice the usable OFDM bandwidth by only 1 GHz, which guarantees the sufficient encoding bitrate for the optically generated MMW carrier to implement the fusion of MMW wireless LAN and DWDM-PON with cost-effective and compact architecture. As a result, the 47.7-GHz MMW carrier remotely beat from the dual-mode master-to-slave injection-locked colorless FPLD pair exhibits an extremely narrow bandwidth of only 0.48 MHz. After frequency down-conversion operation, the 47.7-GHz MMW carrier successfully delivers 4-QAM OFDM data up to 2 Gb/s with EVM, SNR and BER of 33.5%, 9.51 dB and 1.4 × 10(-3), respectively.

Unidirectional, dual-comb lasing under multiple pulse formation mechanisms in a passively mode-locked fiber ring laser

OpenAIRE

Liu, Ya; Zhao, Xin; Hu, Guoqing; Li, Cui; Zhao, Bofeng; Zheng, Zheng

2016-01-01

Dual-comb lasers from which asynchronous ultrashort pulses can be simultaneously generated have recently become an interesting research subject. They could be an intriguing alternative to the current dual-laser optical-frequency-comb source with highly sophisticated electronic control systems. If generated through a common light path traveled by all pulses, the common-mode noises between the spectral lines of different pulse trains could be significantly reduced. Therefore, coherent dual-comb...

Dual-Mode Dual-Band Microstrip Bandpass Filter Based on Fourth Iteration T-Square Fractal and Shorting Pin

Directory of Open Access Journals (Sweden)

E. S. Ahmed

2012-06-01

Full Text Available A new class of dual mode microstrip fractal resonator is proposed and developed for miniaturization of the dual band bandpass filter. The perimeter of the proposed resonator is increased by employing fourth iteration T-square fractal shape. Consequently the lower resonant frequency of the filter is decreased without increasing the usable space. The self similarity of the usable structure enables it to produce the two degenerate modes which are coupled using the proper perturbation technique. The shorting pin is placed at the null in the surface current distribution at the center of the resonator. This shorting pin is coactively coupled to the resonant circuit of the resonator, effectively coupled to the lower degenerate mode and reduces the lower edge band resonant frequency. By adjusting the resonator dimensions and the size of the shorting pin, the resonant frequency and the out-of-band rejection around the transmission bands can be controlled to meet the design requirements. The simulated response of the designed filter has two transmission bands, the first band is from 2.34-3.65 GHz with resonant frequencies at 2.47GHz and 3.55GHz, the second band is from 4.37-5.324GHz with resonant frequencies at 4.5GHz and 5.13GHz. In the pass bands, the group delay is less than 0.65 ns. The proposed filter can be applied to WLAN (2.4 GHz and 5.2 GHz and WiMAX (3.5 GHz and Bluetooth and ZigBee (4.9 GHz.

Dual-Mode Gas Sensor Composed of a Silicon Nanoribbon Field Effect Transistor and a Bulk Acoustic Wave Resonator: A Case Study in Freons

Directory of Open Access Journals (Sweden)

Ye Chang

2018-01-01

Full Text Available In this paper, we develop a novel dual-mode gas sensor system which comprises a silicon nanoribbon field effect transistor (Si-NR FET and a film bulk acoustic resonator (FBAR. We investigate their sensing characteristics using polar and nonpolar organic compounds, and demonstrate that polarity has a significant effect on the response of the Si-NR FET sensor, and only a minor effect on the FBAR sensor. In this dual-mode system, qualitative discrimination can be achieved by analyzing polarity with the Si-NR FET and quantitative concentration information can be obtained using a polymer-coated FBAR with a detection limit at the ppm level. The complementary performance of the sensing elements provides higher analytical efficiency. Additionally, a dual mixture of two types of freons (CFC-113 and HCFC-141b is further analyzed with the dual-mode gas sensor. Owing to the small size and complementary metal-oxide semiconductor (CMOS-compatibility of the system, the dual-mode gas sensor shows potential as a portable integrated sensing system for the analysis of gas mixtures in the future.

Vibrational correlation between conjugated carbonyl and diazo modes studied by single- and dual-frequency two-dimensional infrared spectroscopy

International Nuclear Information System (INIS)

Maekawa, Hiroaki; Sul, Soohwan; Ge, Nien-Hui

2013-01-01

Highlights: ► Vibrational dynamics of conjugated C=O and N=N modes of ethyl diazoacetate was studied. ► Their frequency–frequency correlation functions are different. ► The dual-frequency 2D IR spectrum indicates anticorrelated frequency fluctuations. ► Correlation effects on dual-frequency 2D IR spectra are discussed. ► The existence of cis and trans conformers is revealed in 2D IR spectra. - Abstract: We have applied infrared three-pulse photon echo and single- and dual-frequency 2D IR spectroscopy to the ester C=O and diazo N=N stretching modes in ethyl diazoacetate (EDA), and investigated their vibrational frequency fluctuations and correlation. The two modes exhibit different vibrational dynamics and 2D lineshape, which are well simulated by frequency–frequency correlation functions (FFCFs) with two decaying components. Although the FT IR spectrum shows a single C=O band, absolute magnitude 2D IR nonrephasing spectrum displays spectral signatures supporting the presence of cis and trans conformations. The cross-peak inclined toward the anti-diagonal in the dual-frequency 2D IR spectrum, indicating that the frequency fluctuations of the two modes are anticorrelated. This behavior is attributed to anticorrelated change in the bond orders when solvent and structural fluctuations causes EDA to adopt a different mixture of the two dominant resonance structures. The effects of cross FFCF on the cross-peak line shape are discussed

Vibrational correlation between conjugated carbonyl and diazo modes studied by single- and dual-frequency two-dimensional infrared spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Maekawa, Hiroaki; Sul, Soohwan [Department of Chemistry, University of California at Irvine, Irvine, CA 92697-2025 (United States); Ge, Nien-Hui, E-mail: nhge@uci.edu [Department of Chemistry, University of California at Irvine, Irvine, CA 92697-2025 (United States)

2013-08-30

Highlights: ► Vibrational dynamics of conjugated C=O and N=N modes of ethyl diazoacetate was studied. ► Their frequency–frequency correlation functions are different. ► The dual-frequency 2D IR spectrum indicates anticorrelated frequency fluctuations. ► Correlation effects on dual-frequency 2D IR spectra are discussed. ► The existence of cis and trans conformers is revealed in 2D IR spectra. - Abstract: We have applied infrared three-pulse photon echo and single- and dual-frequency 2D IR spectroscopy to the ester C=O and diazo N=N stretching modes in ethyl diazoacetate (EDA), and investigated their vibrational frequency fluctuations and correlation. The two modes exhibit different vibrational dynamics and 2D lineshape, which are well simulated by frequency–frequency correlation functions (FFCFs) with two decaying components. Although the FT IR spectrum shows a single C=O band, absolute magnitude 2D IR nonrephasing spectrum displays spectral signatures supporting the presence of cis and trans conformations. The cross-peak inclined toward the anti-diagonal in the dual-frequency 2D IR spectrum, indicating that the frequency fluctuations of the two modes are anticorrelated. This behavior is attributed to anticorrelated change in the bond orders when solvent and structural fluctuations causes EDA to adopt a different mixture of the two dominant resonance structures. The effects of cross FFCF on the cross-peak line shape are discussed.

Dual mode linguistic hedge fuzzy logic controller for an isolated wind-diesel hybrid power system with superconducting magnetic energy storage unit

International Nuclear Information System (INIS)

Thameem Ansari, M.Md.; Velusami, S.

2010-01-01

A design of dual mode linguistic hedge fuzzy logic controller for an isolated wind-diesel hybrid power system with superconducting magnetic energy storage unit is proposed in this paper. The design methodology of dual mode linguistic hedge fuzzy logic controller is a hybrid model based on the concepts of linguistic hedges and hybrid genetic algorithm-simulated annealing algorithms. The linguistic hedge operators are used to adjust the shape of the system membership functions dynamically and can speed up the control result to fit the system demand. The hybrid genetic algorithm-simulated annealing algorithm is adopted to search the optimal linguistic hedge combination in the linguistic hedge module. Dual mode concept is also incorporated in the proposed controller because it can improve the system performance. The system with the proposed controller was simulated and the frequency deviation resulting from a step load disturbance is presented. The comparison of the proportional plus integral controller, fuzzy logic controller and the proposed dual mode linguistic hedge fuzzy logic controller shows that, with the application of the proposed controller, the system performance is improved significantly. The proposed controller is also found to be less sensitive to the changes in the parameters of the system and also robust under different operating modes of the hybrid power system.

WE-G-BRA-09: Microsphere Brachytherapy Failure Mode and Effects Analysis in a Dual-Vendor Environment

International Nuclear Information System (INIS)

Younge, K C; Lee, C I; Feng, M; Novelli, P; Moran, J M; Prisciandaro, J I

2015-01-01

Purpose: To improve the safety and quality of a dual-vendor microsphere brachytherapy program with failure mode and effects analysis (FMEA). Methods: A multidisciplinary team including physicists, dosimetrists, a radiation oncologist, an interventional radiologist, and radiation safety personnel performed an FMEA for our dual-vendor microsphere brachytherapy program employing SIR-Spheres (Sirtex Medical Limited, Australia) and Theraspheres (BTG, England). We developed a program process tree and step-by-step instructions which were used to generate a comprehensive list of failure modes. These modes were then ranked according to severity, occurrence rate, and detectability. Risk priority numbers (RPNs) were calculated by multiplying these three scores together. Three different severity scales were created: one each for harmful effects to the patient, staff, or the institution. Each failure mode was ranked on one or more of these scales. Results: The group identified 164 failure modes for the microsphere program. 113 of these were ranked using the patient severity scale, 52 using the staff severity scale, and 50 using the institution severity scale. The highest ranked items on the patient severity scale were an error in the automated dosimetry worksheet (RPN = 297.5), and the incorrect target specified on the planning study (RPN = 135). Some failure modes ranked differently between vendors, especially those corresponding to dose vial preparation because of the different methods used. Based on our findings, we made several improvements to our QA program, including documentation to easily identify which product is being used, an additional hand calculation during planning, and reorganization of QA steps before treatment delivery. We will continue to periodically review and revise the FMEA. Conclusion: We have applied FMEA to our dual-vendor microsphere brachytherapy program to identify potential key weaknesses in the treatment chain. Our FMEA results were used to

WE-G-BRA-09: Microsphere Brachytherapy Failure Mode and Effects Analysis in a Dual-Vendor Environment

Energy Technology Data Exchange (ETDEWEB)

Younge, K C; Lee, C I; Feng, M; Novelli, P; Moran, J M; Prisciandaro, J I [Univ Michigan Medical Center, Ann Arbor, MI (United States)

2015-06-15

Purpose: To improve the safety and quality of a dual-vendor microsphere brachytherapy program with failure mode and effects analysis (FMEA). Methods: A multidisciplinary team including physicists, dosimetrists, a radiation oncologist, an interventional radiologist, and radiation safety personnel performed an FMEA for our dual-vendor microsphere brachytherapy program employing SIR-Spheres (Sirtex Medical Limited, Australia) and Theraspheres (BTG, England). We developed a program process tree and step-by-step instructions which were used to generate a comprehensive list of failure modes. These modes were then ranked according to severity, occurrence rate, and detectability. Risk priority numbers (RPNs) were calculated by multiplying these three scores together. Three different severity scales were created: one each for harmful effects to the patient, staff, or the institution. Each failure mode was ranked on one or more of these scales. Results: The group identified 164 failure modes for the microsphere program. 113 of these were ranked using the patient severity scale, 52 using the staff severity scale, and 50 using the institution severity scale. The highest ranked items on the patient severity scale were an error in the automated dosimetry worksheet (RPN = 297.5), and the incorrect target specified on the planning study (RPN = 135). Some failure modes ranked differently between vendors, especially those corresponding to dose vial preparation because of the different methods used. Based on our findings, we made several improvements to our QA program, including documentation to easily identify which product is being used, an additional hand calculation during planning, and reorganization of QA steps before treatment delivery. We will continue to periodically review and revise the FMEA. Conclusion: We have applied FMEA to our dual-vendor microsphere brachytherapy program to identify potential key weaknesses in the treatment chain. Our FMEA results were used to

Dual-Mode SERS-Fluorescence Immunoassay Using Graphene Quantum Dot Labeling on One-Dimensional Aligned Magnetoplasmonic Nanoparticles.

Science.gov (United States)

Zou, Fengming; Zhou, Hongjian; Tan, Tran Van; Kim, Jeonghyo; Koh, Kwangnak; Lee, Jaebeom

2015-06-10

A novel dual-mode immunoassay based on surface-enhanced Raman scattering (SERS) and fluorescence was designed using graphene quantum dot (GQD) labels to detect a tuberculosis (TB) antigen, CFP-10, via a newly developed sensing platform of linearly aligned magnetoplasmonic (MagPlas) nanoparticles (NPs). The GQDs were excellent bilabeling materials for simultaneous Raman scattering and photoluminescence (PL). The one-dimensional (1D) alignment of MagPlas NPs simplified the immunoassay process and enabled fast, enhanced signal transduction. With a sandwich-type immunoassay using dual-mode nanoprobes, both SERS signals and fluorescence images were recognized in a highly sensitive and selective manner with a detection limit of 0.0511 pg mL(-1).

60-GHz Millimeter-wave Over Fiber with Directly Modulated Dual-mode Laser Diode

Science.gov (United States)

Tsai, Cheng-Ting; Lin, Chi-Hsiang; Lin, Chun-Ting; Chi, Yu-Chieh; Lin, Gong-Ru

2016-01-01

A directly modulated dual-mode laser diode (DMLD) with third-order intermodulation distortion (IMD3) suppression is proposed for a 60-GHz millimeter-wave over fiber (MMWoF) architecture, enabling new fiber-wireless communication access to cover 4-km single-mode-fiber (SMF) and 3-m wireless 16-QAM OFDM transmissions. By dual-mode injection-locking, the throughput degradation of the DMLD is mitigated with saturation effect to reduce its threshold, IMD3 power and relative intensity noise to 7.7 mA, −85 dBm and −110.4 dBc/Hz, respectively, providing huge spurious-free dynamic range of 85.8 dB/Hz2/3. This operation suppresses the noise floor of the DMLD carried QPSK-OFDM spectrum by 5 dB. The optical receiving power is optimized to restrict the power fading effect for improving the bit error rate to 1.9 × 10−3 and the receiving power penalty to 1.1 dB. Such DMLD based hybrid architecture for 60-GHz MMW fiber-wireless access can directly cover the current optical and wireless networks for next-generation indoor and short-reach mobile communications. PMID:27297267

Dual-mode ferromagnetic resonance in an FeCoB/Ru/FeCoB synthetic antiferromagnet with uniaxial anisotropy

Science.gov (United States)

Wang, Cuiling; Zhang, Shouheng; Qiao, Shizhu; Du, Honglei; Liu, Xiaomin; Sun, Ruicong; Chu, Xian-Ming; Miao, Guo-Xing; Dai, Youyong; Kang, Shishou; Yan, Shishen; Li, Shandong

2018-05-01

Dual-mode ferromagnetic resonance is observed in FeCoB/Ru/FeCoB trilayer synthetic antiferromagnets with uniaxial in-plane magnetic anisotropy. The optical mode is present in the (0-108 Oe) magnetic field range, where the top and bottom layer magnetizations are aligned in opposite directions. The strong acoustic mode appears, when the magnetic field exceeds the 300 Oe value, which corresponds to the flop transition in the trilayer. Magnetic field and angular dependences of resonant frequencies are studied for both optical (low-field) and acoustic (high field) modes. The low-field mode is found to be anisotropic but insensitive to the magnetic field value. In contrast, the high field mode is quasi-isotropic, but its resonant frequency is tunable by the value of the magnetic field. The coexistence of two modes of ferromagnetic resonance as well as switching between them with the increase in the magnetic field originates from the difference in the sign of interlayer coupling energy at the parallel and antiparallel configurations of the synthetic antiferromagnet. The dual-mode resonance in the studied trilayer structures provides greater flexibility in the design and functionalization of micro-inductors in monolithic microwave integrated circuits.

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.

Effect of engine load and biogas flow rate to the performance of a compression ignition engine run in dual-fuel (dieselbiogas) mode

Science.gov (United States)

Ambarita, H.

2018-02-01

The Government of Indonesia (GoI) has released a target on reduction Green Houses Gases emissions (GHG) by 26% from level business-as-usual by 2020, and the target can be up to 41% by international supports. In the energy sector, this target can be reached effectively by promoting fossil fuel replacement or blending with biofuel. One of the potential solutions is operating compression ignition (CI) engine in dual-fuel (diesel-biogas) mode. In this study effects of engine load and biogas flow rate on the performance and exhaust gas emissions of a compression ignition engine run in dual-fuel mode are investigated. In the present study, the used biogas is refined with methane content 70% of volume. The objectives are to explore the optimum operating condition of the CI engine run in dual-fuel mode. The experiments are performed on a four-strokes CI engine with rated output power of 4.41 kW. The engine is tested at constant speed 1500 rpm. The engine load varied from 600W to 1500W and biogas flow rate varied from 0 L/min to 6 L/min. The results show brake thermal efficiency of the engine run in dual-fuel mode is better than pure diesel mode if the biogas flow rates are 2 L/min and 4 L/min. It is recommended to operate the present engine in a dual-fuel mode with biogas flow rate of 4 L/min. The consumption of diesel fuel can be replaced up to 50%.

SERS-Fluorescence Dual-Mode pH-Sensing Method Based on Janus Microparticles.

Science.gov (United States)

Yue, Shuai; Sun, Xiaoting; Wang, Ning; Wang, Yaning; Wang, Yue; Xu, Zhangrun; Chen, Mingli; Wang, Jianhua

2017-11-15

A surface-enhanced Raman scattering (SERS)-fluorescence dual-mode pH-sensing method based on Janus microgels was developed, which combined the advantages of high specificity offered by SERS and fast imaging afforded by fluorescence. Dual-mode probes, pH-dependent 4-mercaptobenzoic acid, and carbon dots were individually encapsulated in the independent hemispheres of Janus microparticles fabricated via a centrifugal microfluidic chip. On the basis of the obvious volumetric change of hydrogels in different pHs, the Janus microparticles were successfully applied for sensitive and reliable pH measurement from 1.0 to 8.0, and the two hemispheres showed no obvious interference. The proposed method addressed the limitation that sole use of the SERS-based pH sensing usually failed in strong acidic media. The gastric juice pH and extracellular pH change were measured separately in vitro using the Janus microparticles, which confirmed the validity of microgels for pH sensing. The microparticles exhibited good stability, reversibility, biocompatibility, and ideal semipermeability for avoiding protein contamination, and they have the potential to be implantable sensors to continuously monitor pH in vivo.

Silicon Integrated Dual-Mode Interferometer with Differential Outputs

Directory of Open Access Journals (Sweden)

Niklas Hoppe

2017-09-01

Full Text Available The dual-mode interferometer (DMI is an attractive alternative to Mach-Zehnder interferometers for sensor purposes, achieving sensitivities to refractive index changes close to state-of-the-art. Modern designs on silicon-on-insulator (SOI platforms offer thermally stable and compact devices with insertion losses of less than 1 dB and high extinction ratios. Compact arrays of multiple DMIs in parallel are easy to fabricate due to the simple structure of the DMI. In this work, the principle of operation of an integrated DMI with differential outputs is presented which allows the unambiguous phase shift detection with a single wavelength measurement, rather than using a wavelength sweep and evaluating the optical output power spectrum. Fluctuating optical input power or varying attenuation due to different analyte concentrations can be compensated by observing the sum of the optical powers at the differential outputs. DMIs with two differential single-mode outputs are fabricated in a 250 nm SOI platform, and corresponding measurements are shown to explain the principle of operation in detail. A comparison of DMIs with the conventional Mach-Zehnder interferometer using the same technology concludes this work.

Nonlinear Longitudinal Mode Instability in Liquid Propellant Rocket Engine Preburners

Science.gov (United States)

Sims, J. D. (Technical Monitor); Flandro, Gary A.; Majdalani, Joseph; Sims, Joseph D.

2004-01-01

Nonlinear pressure oscillations have been observed in liquid propellant rocket instability preburner devices. Unlike the familiar transverse mode instabilities that characterize primary combustion chambers, these oscillations appear as longitudinal gas motions with frequencies that are typical of the chamber axial acoustic modes. In several respects, the phenomenon is similar to longitudinal mode combustion instability appearing in low-smoke solid propellant motors. An important feature is evidence of steep-fronted wave motions with very high amplitude. Clearly, gas motions of this type threaten the mechanical integrity of associated engine components and create unacceptably high vibration levels. This paper focuses on development of the analytical tools needed to predict, diagnose, and correct instabilities of this type. For this purpose, mechanisms that lead to steep-fronted, high-amplitude pressure waves are described in detail. It is shown that such gas motions are the outcome of the natural steepening process in which initially low amplitude standing acoustic waves grow into shock-like disturbances. The energy source that promotes this behavior is a combination of unsteady combustion energy release and interactions with the quasi-steady mean chamber flow. Since shock waves characterize the gas motions, detonation-like mechanisms may well control the unsteady combustion processes. When the energy gains exceed the losses (represented mainly by nozzle and viscous damping), the waves can rapidly grow to a finite amplitude limit cycle. Analytical tools are described that allow the prediction of the limit cycle amplitude and show the dependence of this wave amplitude on the system geometry and other design parameters. This information can be used to guide corrective procedures that mitigate or eliminate the oscillations.

Asymmetric dual-loop feedback to suppress spurious tones and reduce timing jitter in self-mode-locked quantum-dash lasers emitting at 155 μm

Science.gov (United States)

Asghar, Haroon; McInerney, John G.

2017-09-01

We demonstrate an asymmetric dual-loop feedback scheme to suppress external cavity side-modes induced in self-mode-locked quantum-dash lasers with conventional single and dual-loop feedback. In this letter, we achieved optimal suppression of spurious tones by optimizing the length of second delay time. We observed that asymmetric dual-loop feedback, with large (~8x) disparity in cavity lengths, eliminates all external-cavity side-modes and produces flat RF spectra close to the main peak with low timing jitter compared to single-loop feedback. Significant reduction in RF linewidth and reduced timing jitter was also observed as a function of increased second feedback delay time. The experimental results based on this feedback configuration validate predictions of recently published numerical simulations. This interesting asymmetric dual-loop feedback scheme provides simplest, efficient and cost effective stabilization of side-band free optoelectronic oscillators based on mode-locked lasers.

Real-time dual-comb spectroscopy with a free-running bidirectionally mode-locked fiber laser

Science.gov (United States)

Mehravar, S.; Norwood, R. A.; Peyghambarian, N.; Kieu, K.

2016-06-01

Dual-comb technique has enabled exciting applications in high resolution spectroscopy, precision distance measurements, and 3D imaging. Major advantages over traditional methods can be achieved with dual-comb technique. For example, dual-comb spectroscopy provides orders of magnitude improvement in acquisition speed over standard Fourier-transform spectroscopy while still preserving the high resolution capability. Wider adoption of the technique has, however, been hindered by the need for complex and expensive ultrafast laser systems. Here, we present a simple and robust dual-comb system that employs a free-running bidirectionally mode-locked fiber laser operating at telecommunication wavelength. Two femtosecond frequency combs (with a small difference in repetition rates) are generated from a single laser cavity to ensure mutual coherent properties and common noise cancellation. As the result, we have achieved real-time absorption spectroscopy measurements without the need for complex servo locking with accurate frequency referencing, and relatively high signal-to-noise ratio.

A Dual-Mode Microwave Applicator for Liver Tumor Thermotherapy

Science.gov (United States)

Reimann, Carolin; Schüßler, Martin; Jakoby, Rolf; Bazrafshan, Babak; Hübner, Frank; Vogl, Thomas

2018-03-01

The concept of a novel dual-mode microwave applicator for diagnosis and thermal ablation treatment of tumorous tissue is presented in this paper. This approach is realized by integrating a planar resonator array to, firstly, detect abnormalities by a relative dielectric analysis, and secondly, perform a highly localized thermal ablation. A further essential advantage is addressed by designing the applicator to be MRI compatible to provide a multimodal imaging procedure. Investigations for an appropriate frequency range lead to the use of much higher operating frequencies between 5 GHz and 10 GHz, providing a significantly lower power consumption for microwave ablation of only 20 W compared to commercial available applicators.

Single longitudinal mode operation of a solid-state dye laser oscillator

CERN Document Server

Lim, G; Kim, H S; Cha, B H; Lee, J M

2000-01-01

We have operated a single longitudinal mode of a solid-state dye laser oscillator in a Littman configuration. The host material of the solid-state gain medium was rhodamine dye-doped poly (methyl methacrylate). The pumping source was the second harmonic of a Nd:YAG laser with a repetition rate of 10 Hz. The measured linewidth of the laser output was about 1.5 GHz.

The application of low frequency longitudinal guided wave mode for the inspection of multi-hole steel floral pipes

International Nuclear Information System (INIS)

Liu, Z H; Xie, X D; Wu, B; Li, Y H; He, C F

2012-01-01

Shed-pipe grouting technology, an effective advanced supporting method, is often used in the excavation of soft strata. Steel floral pipes are one of the key load-carrying components of shed-pipe grouting supporting structures. Guided waves are a very attractive methodology to inspect multi-hole steel floral pipes as they offer long range inspection capability, mode and frequency tuning, and cost effectiveness. In this contribution, preliminary experiments are described for the inspection of steel floral pipes using a low frequency longitudinal guided wave mode, L(0,2). The relation between the number of grouting holes and the peak-to-peak amplitude of the first end-reflected signal was obtained. The effect of the grouting holes in steel floral pipes on the propagation velocity of the L(0,2) mode at 30 kHz was analyzed. Experimental results indicate that the typical grouting holes in steel floral pipe have no significant effect on the propagation of this mode. As a result, low frequency longitudinal guided wave modes have potential for the non-destructive long range inspection of multi-hole steel floral pipes. Furthermore, the propagation velocity of the investigated L(0,2) mode at 30 kHz decreases linearly with the increase of the number of grouting holes in a steel floral pipe. It is also noticeable that the effect of the grouting holes cumulates along with the increase in the number of grouting holes and subsequent increase in reflection times of longitudinal guided waves in the steel floral pipe. The application potential of the low frequency longitudinal guided wave technique for the inspection of embedded steel floral pipes is discussed.

An evaluation of intraoperative and postoperative outcomes of torsional mode versus longitudinal ultrasound mode phacoemulsification: a Meta-analysis

Directory of Open Access Journals (Sweden)

Pia Leon

2016-06-01

Full Text Available AIM: To evaluate and compare the intraoperative parameters and postoperative outcomes of torsional mode and longitudinal mode of phacoemulsification. METHODS: Pertinent studies were identified by a computerized MEDLINE search from January 2002 to September 2013. The Meta-analysis is composed of two parts. In the first part the intraoperative parameters were considered: ultrasound time (UST and cumulative dissipated energy (CDE. The intraoperative values were also distinctly considered for two categories (moderate and hard cataract group depending on the nuclear opacity grade. In the second part of the study the postoperative outcomes as the best corrected visual acuity (BCVA and the endothelial cell loss (ECL were taken in consideration. RESULTS: The UST and CDE values proved statistically significant in support of torsional mode for both moderate and hard cataract group. The analysis of BCVA did not present statistically significant difference between the two surgical modalities. The ECL count was statistically significant in support of torsional mode (P<0.001. CONCLUSION: The Meta-analysis shows the superiority of the torsional mode for intraoperative parameters (UST, CDE and postoperative ECL outcomes.

An evaluation of intraoperative and postoperative outcomes of torsional mode versus longitudinal ultrasound mode phacoemulsification: a Meta-analysis.

Science.gov (United States)

Leon, Pia; Umari, Ingrid; Mangogna, Alessandro; Zanei, Andrea; Tognetto, Daniele

2016-01-01

To evaluate and compare the intraoperative parameters and postoperative outcomes of torsional mode and longitudinal mode of phacoemulsification. Pertinent studies were identified by a computerized MEDLINE search from January 2002 to September 2013. The Meta-analysis is composed of two parts. In the first part the intraoperative parameters were considered: ultrasound time (UST) and cumulative dissipated energy (CDE). The intraoperative values were also distinctly considered for two categories (moderate and hard cataract group) depending on the nuclear opacity grade. In the second part of the study the postoperative outcomes as the best corrected visual acuity (BCVA) and the endothelial cell loss (ECL) were taken in consideration. The UST and CDE values proved statistically significant in support of torsional mode for both moderate and hard cataract group. The analysis of BCVA did not present statistically significant difference between the two surgical modalities. The ECL count was statistically significant in support of torsional mode (P<0.001). The Meta-analysis shows the superiority of the torsional mode for intraoperative parameters (UST, CDE) and postoperative ECL outcomes.

Design of single-longitudinal-mode laser oscillator for edge Thomson scattering system in ITER

International Nuclear Information System (INIS)

Hatae, Takaki; Kusama, Yoshinori; Kubomura, Hiroyuki; Matsuoka, Shin-ichi

2006-06-01

A high output energy (5J) and high repetition rate (100 Hz) laser system is required for the edge Thomson scattering system in ITER. A YAG laser (Nd:YAG laser) is a first candidate for the laser system satisfying the requirements. It is important to develop a high beam quality and single longitudinal mode (SLM) laser oscillator in order to realize this high power laser system. In this design work, following activities relating to the SLM laser oscillator have been carried out: design of the laser head and the resonator, estimation of the output power for the SLM laser oscillator, consideration of the feedback control scheme and consideration of interface for amplification system to achieve required performance (5J, 100 Hz). It is expected that the designed laser diode (LD) pumped SLM laser oscillator realizes: 100 Hz of repetition rate, 10 mJ of output energy, 10 ns of pulse width, single longitudinal mode, TEM 00 of transversal mode, divergence less than 4 times of the diffraction limit, energy stability within 5%. (author)

Mini-cavity plasma core reactors for dual-mode space nuclear power/propulsion systems

International Nuclear Information System (INIS)

Chow, S.

1976-01-01

A mini-cavity plasma core reactor is investigated for potential use in a dual-mode space power and propulsion system. In the propulsive mode, hydrogen propellant is injected radially inward through the reactor solid regions and into the cavity. The propellant is heated by both solid driver fuel elements surrounding the cavity and uranium plasma before it is exhausted out the nozzle. The propellant only removes a fraction of the driver power, the remainder is transferred by a coolant fluid to a power conversion system, which incorporates a radiator for heat rejection. In the power generation mode, the plasma and propellant flows are shut off, and the driver elements supply thermal power to the power conversion system, which generates electricity for primary electric propulsion purposes

Web-Face-to-Face Mixed-Mode Design in a Longitudinal Survey: Effects on Participation Rates, Sample Composition, and Costs

Directory of Open Access Journals (Sweden)

Bianchi Annamaria

2017-06-01

Full Text Available Sequential mixed-mode designs are increasingly considered as an alternative to interviewer-administered data collection, allowing researchers to take advantage of the benefits of each mode. We assess the effects of the introduction of a sequential web-face-to-face mixed-mode design over three waves of a longitudinal survey in which members were previously interviewed face-to-face. Findings are reported from a large-scale randomised experiment carried out on the UK Household Longitudinal Study. No differences are found between the mixed-mode design and face-to-face design in terms of cumulative response rates and only minimal differences in terms of sample composition. On the other hand, potential cost savings are evident.

Effect of universal adhesive etching modes on bond strength to dual-polymerizing composite resins.

Science.gov (United States)

Michaud, Pierre-Luc; Brown, Matthew

2018-04-01

Information is lacking as to the effect on bond strength of the etching modes of universal adhesives when they are used to bond dual-polymerizing composite resins to dentin. The purpose of this in vitro study was to investigate the bonding of dual-polymerizing foundation composite resins to dentin when universal bonding agents are used in self-etch or etch-and-rinse modes. Sixty caries-free, extracted third molar teeth were sectioned transversely in the apical third of the crown and allocated to 12 groups (n=5). Three different bonding agents (Scotchbond Universal, OptiBond XTR, All-Bond Universal) were used to bond 2 different dual-polymerizing composite resins (CompCore AF or CoreFlo DC) to dentin, using 2 different etching approaches (etch-and-rinse or self-etch). The specimens were sectioned into sticks (1×1×8 mm) with a precision saw. The bond strength of the specimens was tested under microtensile force at a crosshead speed of 0.5 mm/min. The data were analyzed using a 3-way ANOVA, a Games-Howell post hoc comparisons model, and Student t tests with Bonferroni corrections (α=.05). In the overall model, the composite resin used had no effect on bond strength (P=.830). The etching protocol by itself also did not have a significant effect (P=.059), although a trend was present. The bonding agent, however, did have an effect (Pcomposite resins to dentin, no single etching protocol is better than another. Depending on which bonding agent is being used, one etching mode may perform better. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Microwave measurements of energy lost to longitudinal modes by single electron bunches traversing periodic structures

International Nuclear Information System (INIS)

Wang, J.W.; Loew, G.A.; Weaver, J.N.; Wilson, P.B.

1981-10-01

In the design of future linear colliders, it will be important to minimize the loss of beam energy due to the excitation of higher-order modes in the accelerator structure by single bunches of electrons or positrons. This loss is not only detrimental in itself but also gives rise to energy spectrum widening and transverse emittance growth. Microwave measurements made on disk-loaded and alternating-spoke structures to determine the loss to the longitudinal modes are described. In these measurements the Gaussian bunch is simulated by a current pulse of the same shape transmitted through the structure on an axial center conductor. Results to date are presented for the total longitudinal loss parameter per period K in volts per picocoulomb

Highly Luminescent Dual Mode Polymeric Nanofiber-Based Flexible Mat for White Security Paper and Encrypted Nanotaggant Applications.

Science.gov (United States)

Gangwar, Amit Kumar; Gupta, Ashish; Kedawat, Garima; Kumar, Pawan; Singh, Bhanu Pratap; Singh, Nidhi; Srivastava, Avanish K; Dhakate, Sanjay R; Gupta, Bipin Kumar

2018-05-23

Increasing counterfeiting of important data, currency, stamp papers, branded products etc., has become a major security threat which could lead to serious damage to the global economy. Consequences of such damage are compelling for researchers to develop new high-end security features to address full-proof solutions. Herein, we report a dual mode flexible highly luminescent white security paper and nanotaggants composed of nanophosphors incorporated in polymer matrix to form a nanofiber-based mat for anti-counterfeiting applications. The dual mode nanofibers are fabricated by electrospinning technique by admixing the composite of NaYF 4 :Eu 3+ @NaYF 4 :Yb 3+ , Er 3+ nanophosphors in the polyvinyl alcohol solution. This flexible polymer mat derived from nanofibers appears white in daylight, while emitting strong red (NaYF 4 :Eu 3+ ) and green (NaYF 4 :Yb 3+ , Er 3+ ) colors at excitation wavelengths of 254 nm and 980 nm, respectively. These luminescent nanofibers can also be encrypted as a new class of nanotaggants to protect confidential documents. These obtained results suggest that highly luminescent dual mode polymeric nanofiber-based flexible white security paper and nanotaggants could offer next-generation high-end unique security features against counterfeiting. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Investigation on utilization of biogas and Karanja oil biodiesel in dual fuel mode in a single cylinder DI diesel engine

Energy Technology Data Exchange (ETDEWEB)

Prasanna Pattanaik, Bhabani; Nayak, Chandrakanta [Department of Mechanical Eng., Gandhi Institute for Technological Advancement, Madanpur, Bhubaneswar - 752054, Odisha (India); Kumar Nanda, Basanta [Department of Mechanical Eng., Maharaja Institute of Technology, Bhubaneswar, Odisha (India)

2013-07-01

In this work, experiments were performed on a single cylinder DI diesel engine by using bio-gas as a primary fuel and Karanja oil biodiesel and diesel oil as secondary fuels in dual fuel operation. The experiments were performed to measure performance parameters i.e. (brake specific fuel consumption, brake thermal efficiency and exhaust gas temperature) and emission parameters such as carbon monoxide, carbon dioxide, nitrogen oxide unburned hydro carbon and smoke etc. at different load conditions. For the dual-fuel system, the intake system of the test engine was modified to convert into biogas and biodiesel of a dual-fueled combustion engine. Biogas was injected during the intake process by gas injectors. The study showed that, the engine performance parameters like BP, BTE and EGT gradually increase with increase in engine load for all test conditions using both pilot fuels diesel and KOBD. However, the BSFC of the engine showed decreasing slope with increase in engine load for all test conditions. Above 40% engine load the BSFC values for all test fuels are very close to each other. The engine emission analysis showed that the CO2, CO and NOx emissions increase with increase in engine load for both single and dual fuel mode operation using both pilot fuels. The NOx concentration of exhaust gases in dual fuel mode is superior than that of single mode.

Study on using acetylene in dual fuel mode with exhaust gas recirculation

International Nuclear Information System (INIS)

Lakshmanan, T.; Nagarajan, G.

2011-01-01

Interest in employing gaseous fuels to internal combustion (IC) engines whether for stationary or mobile automotive applications has gained importance because of the economical, sustainable and environmental technical features associated with their usage. However, the incidence of preignition and knock remains a significant barrier in achieving their optimum performance potential. With the advent of latest technologies, the above barriers are eliminated. One such technique is timed manifold injection (TMI) of the gaseous fuel, which is controlled electronically to precisely monitor the induction of fuel to overcome the preignition problem in the intake. In the present investigation, acetylene was injected in the intake manifold in a single cylinder diesel engine, with a gas flow rate of 240 g/h, start of injection time is 10 o aTDC and 90 o CA (9.9 ms) duration, operated in dual fuel mode. In order to decrease the NOx emissions from acetylene-diesel engine, cooled EGR was employed. The cylinder pressure, brake thermal efficiency and emissions such as NOx, smoke, CO, HC, CO 2 and exhaust gas temperature were studied. Dual fuel operation with acetylene induction coupled with cooled EGR results in lowered NOx emissions and improved part load performance. -- Highlights: → Acetylene was tried in SI engines, but due to backfire further research was hindered as an alternative fuel. → But it is not tried in CI engine. Timed manifold injection was tried in diesel engine in the present work to combat backfire. → Author was successful in running the diesel engine in dual fuel mode. → 21% maximum diesel replacement was achieved. Author is confident that acetylene will be commercialised as a fuel for diesel engine in future.

Nonlinear defect localized modes and composite gray and anti-gray solitons in one-dimensional waveguide arrays with dual-flip defects

Science.gov (United States)

Liu, Yan; Guan, Yefeng; Li, Hai; Luo, Zhihuan; Mai, Zhijie

2017-08-01

We study families of stationary nonlinear localized modes and composite gray and anti-gray solitons in a one-dimensional linear waveguide array with dual phase-flip nonlinear point defects. Unstaggered fundamental and dipole bright modes are studied when the defect nonlinearity is self-focusing. For the fundamental modes, symmetric and asymmetric nonlinear modes are found. Their stable areas are studied using different defect coefficients and their total power. For the nonlinear dipole modes, the stability conditions of this type of mode are also identified by different defect coefficients and the total power. When the defect nonlinearity is replaced by the self-defocusing one, staggered fundamental and dipole bright modes are created. Finally, if we replace the linear waveguide with a full nonlinear waveguide, a new type of gray and anti-gray solitons, which are constructed by a kink and anti-kink pair, can be supported by such dual phase-flip defects. In contrast to the usual gray and anti-gray solitons formed by a single kink, their backgrounds on either side of the gray hole or bright hump have the same phase.

Modeling and experimental analysis of the linear ultrasonic motor with in-plane bending and longitudinal mode.

Science.gov (United States)

Wan, Zhijian; Hu, Hong

2014-03-01

A novel linear ultrasonic motor based on in-plane longitudinal and bending mode vibration is presented in this paper. The stator of the motor is composed of a metal plate and eight piezoelectric ceramic patches. There are four long holes in the plate, designed for consideration of the longitudinal and bending mode coupling. The corresponding model is developed to optimize the mechanical and electrical coupling of the stator, which causes an ellipse motion at the contact tip of the stator when the composite vibrations with longitudinal and bending are excited. Its harmonic and transient responses are simulated and inspected. A prototype based on the model is fabricated and used to conduct experiments. Results show that the amplitude of the stator's contact tips is significantly increased, which helps to amplify the driving force and speed of the motor. It is therefore feasible to implement effective linear movement using the developed prototype. Copyright © 2013 Elsevier B.V. All rights reserved.

Corneal endothelial morphology and function after torsional and longitudinal ultrasound mode phacoemulsification.

Science.gov (United States)

Módis, László Jr; Szalai, Eszter; Flaskó, Zsuzsa; Németh, Gábor

2016-01-01

To study the endothelial cell morphology and corneal thickness changes after phacoemulsification by using the OZil torsional and longitudinal ultrasound techniques (Infiniti Vision System, Alcon Laboratories). Department of Ophthalmology, Clinical Center, University of Debrecen, Debrecen, Hungary. 52 patients with cataract were randomly assigned to longitudinal ultrasound and torsional mode group. All surgeries were performed through a 2.2 mm clear corneal incision, the method employed being divide and conquer. The endothelial morphometry such as cell density (ECD), mean cell area, coefficient of variation of cell area, and central corneal thickness were examined with specular microscopy (EM-1000, Tomey) preoperatively and 4, 8 weeks postoperatively. ECD values decreased significantly in both surgical groups (P .05). No significant correlation was found between the endothelial cell loss and the nucleus density. Both phacoemulsification techniques were safe and effective. The torsional handpiece performs oscillatory movements and delivers less energy into the eye than the longitudinal ultrasound technique, therefore providing more favorable energy and thermal safety profile.

TH-C-18A-02: Machine Learning and STAPLE Based Simultaneous Longitudinal Segmentation of Bone and Marrow Structures From Dual Energy CT

International Nuclear Information System (INIS)

Fehr, D; Schmidtlein, C; Hwang, S; Deasy, J; Veeraraghavan, H

2014-01-01

Purpose: To develop a fully-automatic longitudinal bone and marrow segmentation method in the pelvic region from dual energy computed tomography (DECT). Methods: We developed a two-step automatic bone and marrow segmentation method for simultaneous longitudinal evaluation of patients with metastatic bone disease using dual energy CT (DECT). Our approach transforms the DECT images into a multi-material decomposition (MMD) model that represents the voxels as a mixture of multiple materials. A support vector machine (SVM) was trained using a single scan. In the first step of the longitudinal segmentation the trained SVM model detects bone and marrow structures on all available longitudinal scans. Segmentation is further refined through active contour segmentation. In the second step, the segmentations from the individual scans are merged by employing the simultaneous truth and performance level estimation (STAPLE) algorithm. The scans are registered using affine and deformable registration. We found that our approach improves the segmentation in all the scans under reliable registration performance between the same scans. Improving registration was not under the scope of this work. Results: We applied our approach to segment bone and marrow in DECT scans in the pelvic regions for multiple patients. Each patient had three to five follow up scans. All the patients in the analysis had artificial metal prostheses which introduced challenges for the registration. Our algorithm achieved reasonable accurate segmentation despite the presence of metal artifacts and high-density oral contrast in neighboring structures. Our approach obtained an overall segmentation accuracy of 80% using DICE metric. Conclusion: We developed a two-step automatic longitudinal segmentation technique for bone and marrow region structures in the pelvic areas from dual energy CT. Our approach achieves robust segmentation despite the presence of confounding structures with similar intensities as the

Optical frequency comb generation based on the dual-mode square microlaser and a nonlinear fiber loop

Science.gov (United States)

Weng, Hai-Zhong; Han, Jun-Yuan; Li, Qing; Yang, Yue-De; Xiao, Jin-Long; Qin, Guan-Shi; Huang, Yong-Zhen

2018-05-01

A novel approach using a dual-mode square microlaser as the pump source is demonstrated to produce wideband optical frequency comb (OFC). The enhanced nonlinear frequency conversion processes are accomplished in a nonlinear fiber loop, which can reduce the stimulated Brillouin scattering threshold and then generate a dual-mode Brillouin laser with improved optical signal-to-noise ratio. An OFC with 130 nm bandwidth and 76 GHz repetition rate is successfully generated under the four-wave mixing, and the number of the comb lines is enhanced by 26 times compared with the system without fiber loop. In addition, the repetition rate of the comb can be adjusted by changing the injection current of the microlaser. The pulse width of the comb spectrum is also compressed from 3 to 1 ps with an extra amplification-nonlinear process.

Melanin-originated carbonaceous dots for triple negative breast cancer diagnosis by fluorescence and photoacoustic dual-mode imaging.

Science.gov (United States)

Xiao, Wei; Li, Yuan; Hu, Chuan; Huang, Yuan; He, Qin; Gao, Huile

2017-07-01

Carbonaceous dots exhibit increasing applications in diagnosis and drug delivery due to excellent photostability and biocompatibility properties. However, relative short excitation and emission of melanin carbonaceous dots (MCDs) limit the applicability in fluorescence bioimaging. Furthermore, the generally poor spatial resolution of fluorescence imaging limits potential in vivo applications. Due to a variety of beneficial properties, in this study, MCDs were prepared exhibiting great potential in fluorescence and photoacoustic dual-mode bioimaging. The MCDs exhibited a long excitation peak at 615nm and emission peak at 650nm, further highlighting the applicability in fluorescence imaging, while the absorbance peak at 633nm renders MCDs suitable for photoacoustic imaging. In vivo, the photoacoustic signal of MCDs was linearly correlated with the concentration of MCDs. Moreover, the MCDs were shown to be taken up into triple negative breast cancer cell line 4T1 in both a time- and concentration-dependent manner. In vivo fluorescence and photoacoustic imaging of subcutaneous 4T1 tumor demonstrated that MCDs could passively target triple negative breast cancer tissue by enhanced permeability and retention effects and may therefore be used for tumor dual-mode imaging. Furthermore, fluorescence distribution in tissue slices suggested that MCDs may distribute in 4T1 tumor with high efficacy. In conclusion, the MCDs studied offer potential application in fluorescence and photoacoustic dual-mode imaging. Copyright © 2017 Elsevier Inc. All rights reserved.

Effect of curing modes of dual-curing core systems on microtensile bond strength to dentin and formation of an acid-base resistant zone.

Science.gov (United States)

Li, Na; Takagaki, Tomohiro; Sadr, Alireza; Waidyasekera, Kanchana; Ikeda, Masaomi; Chen, Jihua; Nikaido, Toru; Tagami, Junji

2011-12-01

To evaluate the microtensile bond strength (μTBS) and acid-base resistant zone (ABRZ) of two dualcuring core systems to dentin using four curing modes. Sixty-four caries-free human molars were randomly divided into two groups according to two dual-curing resin core systems: (1) Clearfil DC Core Automix; (2) Estelite Core Quick. For each core system, four different curing modes were applied to the adhesive and core resin: (1) dual-cured and dual-cured (DD); (2) chemically cured and dual-cured (CD); (3) dual-cured and chemically cured (DC); (4) chemically cured and chemically cured (CC). The specimens were sectioned into sticks (n = 20 for each group) for the microtensile bond test. μTBS data were analyzed using two-way ANOVA and the Dunnett T3 test. Failure patterns were examined with scanning electron microscopy (SEM) to determine the proportion of each mode. Dentin sandwiches were produced and subjected to an acid-base challenge. After argon-ion etching, the ultrastructure of ABRZ was observed using SEM. For Clearfil DC Core Automix, the μTBS values in MPa were as follows: DD: 29.1 ± 5.4, CD: 21.6 ± 5.6, DC: 17.9 ± 2.8, CC: 11.5 ± 3.2. For Estelite Core Quick, they were: DD: 48.9 ±5.7, CD: 20.5 ± 4.7, DC: 41.4 ± 8.3, CC: 19.1 ± 6.0. The bond strength was affected by both material and curing mode, and the interaction of the two factors was significant (p < 0.001). Within both systems, there were significant differences among groups, and the DD group showed the highest μTBS (p < 0.05). ABRZ morphology was not affected by curing mode, but it was highly adhesive-material dependent. The curing mode of dual-curing core systems affects bond strength to dentin, but has no significant effect on the formation of ABRZ.

A dual-mode operation overmoded coaxial millimeter-wave generator with high power capacity and pure transverse electric and magnetic mode output

Science.gov (United States)

Bai, Zhen; Zhang, Jun; Zhong, Huihuang

2016-04-01

An overmoded coaxial millimeter-wave generator with high power capacity and pure transverse electric and magnetic (TEM) mode output is designed and presented, by using a kind of coaxial slow wave structure (SWS) with large transversal dimension and small distance between inner and outer conductors. The generator works in dual-mode operation mechanism. The electron beam synchronously interacts with 7π/8 mode of quasi-TEM, at the meanwhile exchanges energy with 3π/8 mode of TM01. The existence of TM01 mode, which is traveling wave, not only increases the beam-wave interaction efficiency but also improves the extraction efficiency. The large transversal dimension of coaxial SWS makes its power capacity higher than that of other reported millimeter-wave devices and the small distance between inner and outer conductors allows only two azimuthally symmetric modes to coexist. The converter after the SWS guarantees the mode purity of output power. Particle-in-cell simulation shows that when the diode voltage is 400 kV and beam current is 3.8 kA, the generation of microwave at 32.26 GHz with an output power of 611 MW and a conversion efficiency of 40% is obtained. The power percentage carried by TEM mode reaches 99.7% in the output power.

Vibrational correlation between conjugated carbonyl and diazo modes studied by single- and dual-frequency two-dimensional infrared spectroscopy

Science.gov (United States)

Maekawa, Hiroaki; Sul, Soohwan; Ge, Nien-Hui

2013-08-01

We have applied infrared three-pulse photon echo and single- and dual-frequency 2D IR spectroscopy to the ester Cdbnd O and diazo Ndbnd N stretching modes in ethyl diazoacetate (EDA), and investigated their vibrational frequency fluctuations and correlation. The two modes exhibit different vibrational dynamics and 2D lineshape, which are well simulated by frequency-frequency correlation functions (FFCFs) with two decaying components. Although the FT IR spectrum shows a single Cdbnd O band, absolute magnitude 2D IR nonrephasing spectrum displays spectral signatures supporting the presence of cis and trans conformations. The cross-peak inclined toward the anti-diagonal in the dual-frequency 2D IR spectrum, indicating that the frequency fluctuations of the two modes are anticorrelated. This behavior is attributed to anticorrelated change in the bond orders when solvent and structural fluctuations causes EDA to adopt a different mixture of the two dominant resonance structures. The effects of cross FFCF on the cross-peak line shape are discussed.

HIFU Monitoring and Control with Dual-Mode Ultrasound Arrays

Science.gov (United States)

Casper, Andrew Jacob

The biological effects of high-intensity focused ultrasound (HIFU) have been known and studied for decades. HIFU has been shown capable of treating a wide variety of diseases and disorders. However, despite its demonstrated potential, HIFU has been slow to gain clinical acceptance. This is due, in part, to the difficulty associated with robustly monitoring and controlling the delivery of the HIFU energy. The non-invasive nature of the surgery makes the assessment of treatment progression difficult, leading to long treatment times and a significant risk of under treatment. This thesis research develops new techniques and systems for robustly monitoring HIFU therapies for the safe and efficacious delivery of the intended treatment. Systems and algorithms were developed for the two most common modes of HIFU delivery systems: single-element and phased array applicators. Delivering HIFU with a single element transducer is a widely used technique in HIFU therapies. The simplicity of a single element offers many benefits in terms of cost and overall system complexity. Typical monitoring schemes rely on an external device (e.g. diagnostic ultrasound or MRI) to assess the progression of therapy. The research presented in this thesis explores using the same element to both deliver and monitor the HIFU therapy. The use of a dual-mode ultrasound transducer (DMUT) required the development of an FPGA based single-channel arbitrary waveform generator and high-speed data acquisition unit. Data collected from initial uncontrolled ablations led to the development of monitoring and control algorithms which were implemented directly on the FPGA. Close integration between the data acquisition and arbitrary waveform units allowed for fast, low latency control over the ablation process. Results are presented that demonstrate control of HIFU therapies over a broad range of intensities and in multiple in vitro tissues. The second area of investigation expands the DMUT research to an

Dual mode operation, highly selective nanohole array-based plasmonic colour filters

Science.gov (United States)

Fouladi Mahani, Fatemeh; Mokhtari, Arash; Mehran, Mahdiyeh

2017-09-01

Taking advantage of nanostructured metal films as plasmonic colour filters (PCFs) has been evolved remarkably as an alternative to the conventional technologies of chemical colour filtering. However, most of the proposed PCFs depict a poor colour purity focusing on generating either the additive or subtractive colours. In this paper, we present dual mode operation PCFs employing an opaque aluminium film patterned with sub-wavelength holes. Subtractive colours like cyan, magenta, and yellow are the results of reflection mode of these filters yielding optical efficiencies as high as 70%-80% and full width at half maximum of the stop-bands up to 40-50 nm. The colour selectivity of the transmission mode for the additive colours is also significant due to their enhanced performance through the utilization of a relatively thick aluminium film in contact with a modified dielectric environment. These filters provide a simple design with one-step lithography in addition to compatibility with the conventional CMOS processes. Moreover, they are polarization insensitive due to their symmetric geometry. A complete palette of pure subtractive and additive colours has been realized with potential applications, such as multispectral imaging, CMOS image sensors, displays, and colour printing.

Formation of multifunctional Fe3O4/Au composite nanoparticles for dual-mode MR/CT imaging applications

International Nuclear Information System (INIS)

Hu Yong; Li Jing-Chao; Shen Ming-Wu; Shi Xiang-Yang

2014-01-01

Recent advances with iron oxide/gold (Fe 3 O 4 /Au) composite nanoparticles (CNPs) in dual-modality magnetic resonance (MR) and computed tomography (CT) imaging applications are reviewed. The synthesis and assembly of “dumbbelllike” and “core/shell” Fe 3 O 4 /Au CNPs is introduced. Potential applications of some developed Fe 3 O 4 /Au CNPs as contrast agents for dual-mode MR/CT imaging applications are described in detail. (topical review - magnetism, magnetic materials, and interdisciplinary research)

Saline-enhanced hepatic radiofrequency ablation using a perfused-cooled electrode: comparison of dual probe bipolar mode with monopolar and single probe bipolar modes

International Nuclear Information System (INIS)

Lee, Jeong Min; Han, Joon Koo; Kim, Se Hyung; Lee, Jae Young; Kim, Dae Jin; Lee, Min Woo; Cho, Gyung Goo; Han, Chang Jin; Choi, Byung Ihn

2004-01-01

To determine whether saline-enhanced dual probe bipolar radiofrequency ablation (RFA) using perfused-cooled electrodes shows better in-vitro efficiency than monopolar or single probe bipolar RFA in creating larger coagulation necrosis. RF was applied to excised bovine livers in both bipolar and monopolar modes using a 200W generator (CC-3; Radionics) and the perfused-cooled electrodes for 10 mins. After placing single or double perfused-cooled electrodes in the explanted liver, 30 ablation zones were created at three different regimens: group A; saline-enhanced monopolar RFA, group B; saline-enhanced single probe bipolar RFA, and group C; saline-enhanced dual probe bipolar RFA. During RFA, we measured the tissue temperature at 15mm from the electrode. The dimensions of the ablation zones and changes in the impedance currents and liver temperature during RFA were then compared between the groups. The mean current values were higher for monopolar mode (group A) than for the bipolar modes (group B and C): 1550 ± 25 mA in group A, 764 ±189 mA in group B and 819 ± 98 mA in group C(ρ 3 in group A, 23.7 ±3.8 cm 3 in group B, and 34.2 ± 5.1 cm 3 in group C(ρ 0.05). The temperature at 15 mm from the electrode was higher in group C than in the other groups: 70 ± 18 .deg. C in group A, 59 ± 23 .deg. C in group B and 96 ± 16 .deg. C in group C (ρ < 0.05). Saline-enhanced bipolar RFA using dual perfused-cooled electrodes increases the dimension of the ablation zone more efficiently than monopolar RFA or single probe bipolar RFA

A Plasma Based OES-CRDS Dual-mode Portable Spectrometer for Trace Element Detection: Emission and Ringdown Measurements of Mercury

Science.gov (United States)

Sahay, Peeyush; Scherrer, Susan; Wang, Chuji

2012-10-01

Design and development of a plasma based optical emission spectroscopy-cavity ringdown spectroscopy (OES-CRDS) dual-mode portable spectrometer for in situ monitoring of trace elements is described. A microwave plasma torch (MPT) has been utilized, which serves both as an atomization and excitation source for the two modes, viz. OES and CRDS, of the spectrometer. Operation of both modes of the instrument is demonstrated with initial measurements of elemental mercury (Hg). A detection limit of 44 ng mL-1 for Hg at 253.65 nm was determined with the emission mode of the instrument. Severe radiation trapping of 253.65 nm line hampers the measurement of Hg in higher concentration region (> 50 μg ml-1). Therefore, a different wavelength, 365.01 nm, is suggested to measure Hg in that region. Ringdown measurements of the metastable 6s6p ^3P0 state of Hg in the plasma using a 404.65 nm palm size diode laser was conducted to demonstrate the CRDS mode of the instrument. Along with being portable, dual-mode, and self-calibrated, the instrument is capable of measuring a wide range of concentration ranging from sub ng mL-1 to several μg ml-1 for a number of elements.

Beating the Odds: A Longitudinal Investigation of Low-Income Dual-Language and Monolingual Children's English Language and Literacy Performance

Science.gov (United States)

Han, Myae; Vukelich, Carol; Buell, Martha; Meacham, Sohyun

2014-01-01

Research Findings: The current study reports on the results of a longitudinal investigation of the language and early literacy development of a sample of dual-language learners (DLLs) and monolingual English speakers from low-income families who received an Early Reading First intervention during their Head Start preschool year. A total of 62…

A dual-mode operation overmoded coaxial millimeter-wave generator with high power capacity and pure transverse electric and magnetic mode output

Energy Technology Data Exchange (ETDEWEB)

Bai, Zhen; Zhang, Jun, E-mail: zhangjun@nudt.edu.cn; Zhong, Huihuang [College of Optoelectric Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

2016-04-15

An overmoded coaxial millimeter-wave generator with high power capacity and pure transverse electric and magnetic (TEM) mode output is designed and presented, by using a kind of coaxial slow wave structure (SWS) with large transversal dimension and small distance between inner and outer conductors. The generator works in dual-mode operation mechanism. The electron beam synchronously interacts with 7π/8 mode of quasi-TEM, at the meanwhile exchanges energy with 3π/8 mode of TM{sub 01}. The existence of TM{sub 01} mode, which is traveling wave, not only increases the beam-wave interaction efficiency but also improves the extraction efficiency. The large transversal dimension of coaxial SWS makes its power capacity higher than that of other reported millimeter-wave devices and the small distance between inner and outer conductors allows only two azimuthally symmetric modes to coexist. The converter after the SWS guarantees the mode purity of output power. Particle-in-cell simulation shows that when the diode voltage is 400 kV and beam current is 3.8 kA, the generation of microwave at 32.26 GHz with an output power of 611 MW and a conversion efficiency of 40% is obtained. The power percentage carried by TEM mode reaches 99.7% in the output power.

Tunable and switchable dual-wavelength single polarization narrow linewidth SLM erbium-doped fiber laser based on a PM-CMFBG filter.

Science.gov (United States)

Yin, Bin; Feng, Suchun; Liu, Zhibo; Bai, Yunlong; Jian, Shuisheng

2014-09-22

A tunable and switchable dual-wavelength single polarization narrow linewidth single-longitudinal-mode (SLM) erbium-doped fiber (EDF) ring laser based on polarization-maintaining chirped moiré fiber Bragg grating (PM-CMFBG) filter is proposed and demonstrated. For the first time as we know, the CMFBG inscribed on the PM fiber is applied for the wavelength-tunable and-switchable dual-wavelength laser. The PM-CMFBG filter with ultra-narrow transmission band (0.1 pm) and a uniform polarization-maintaining fiber Bragg grating (PM-FBG) are used to select the laser longitudinal mode. The stable single polarization SLM operation is guaranteed by the PM-CMFBG filter and polarization controller. A tuning range of about 0.25 nm with about 0.075 nm step is achieved by stretching the uniform PM-FBG. Meanwhile, the linewidth of the fiber laser for each wavelength is approximate 6.5 and 7.1 kHz with a 20 dB linewidth, which indicates the laser linewidth is approximate 325 Hz and 355 Hz FWHM.

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.

Experimental study on combustion modes and thrust performance of a staged-combustor of the scramjet with dual-strut

Science.gov (United States)

Yang, Qingchun; Chetehouna, Khaled; Gascoin, Nicolas; Bao, Wen

2016-05-01

To enable the scramjet operate in a wider flight Mach number, a staged-combustor with dual-strut is introduced to hold more heat release at low flight Mach conditions. The behavior of mode transition was examined using a direct-connect model scramjet experiment along with pressure measurements. The typical operating modes of the staged-combustor are analyzed. Fuel injection scheme has a significant effect on the combustor operating modes, particularly for the supersonic combustion mode. Thrust performances of the combustor with different combustion modes and fuel distributions are reported in this paper. The first-staged strut injection has a better engine performance in the operation of subsonic combustion mode. On the contrast, the second-staged strut injection has a better engine performance in the operation of supersonic combustion mode.

Dual-wavelength passive and hybrid mode-locking of 3, 4.5 and 10 GHz InAs/InP(100) quantum dot lasers.

Science.gov (United States)

Tahvili, M S; Du, L; Heck, M J R; Nötzel, R; Smit, M K; Bente, E A J M

2012-03-26

We present an investigation of passive and hybrid mode-locking in Fabry-Pérot type two-section InAs/InP(100) quantum dot lasers that show dual wavelength operation. Over the whole current and voltage range for mode-locking of these lasers, the optical output spectra show two distinct lobes. The two lobes provide a coherent bandwidth and are verified to lead to two synchronized optical pulses. The generated optical pulses are elongated in time due to a chirp which shows opposite signs over the two spectral lobes. Self-induced mode-locking in the single-section laser shows that the dual-wavelength spectra correspond to emission from ground state. In the hybrid mode-locking regime, a map of locking range is presented by measuring the values of timing jitter for several values of power and frequency of the external electrical modulating signal. An overview of the systematic behavior of InAs/InP(100) quantum dot mode-locked lasers is presented as conclusion.

Tunable single-polarization single-longitudinal-mode erbium-doped fiber ring laser employing a CMFBG filter and saturable absorber

Science.gov (United States)

Feng, Suchun; Lu, Shaohua; Peng, Wanjing; Li, Qi; Feng, Ting; Jian, Shuisheng

2013-04-01

A tunable single-polarization single-longitudinal-mode (SLM) erbium-doped fiber ring laser is proposed and demonstrated. For the first time as we know, a chirped moiré fiber Bragg grating (CMFBG) filter with ultra-narrow transmission band and a uniform fiber Bragg grating (UFBG) are used to select the laser longitudinal mode. The stable SLM operation of the fiber laser is guaranteed by the combination of the CMFBG filter and 3 m unpumped erbium-doped fiber acting as a saturable absorber. The single polarization operation of the fiber laser is obtained by using an inline broadband polarizer. A tuning range of about 0.7 nm with about 0.1 nm step is achieved by stretching the uniform FBG.

Micro generation of electricity with gasification gas in a engine generator in dual mode; Microgeracao de eletricidade com gas de gaseificacao num motor gerador dual

Energy Technology Data Exchange (ETDEWEB)

Silva, Marcelo Jose da; Souza, Samuel Nelson Melegari de; Souza, Abel Alves de; Ricieri, Reinaldo P. [Universidade Estadual do Oeste do Parana (UNIOESTE), Cascavel, PE (Brazil)], E-mail: marcelo_js07@hotmail.com

2010-07-01

Among the alternatives to the increase of world energy demand the use of biomass as energy source is one of the most promising as it contributes to reducing emissions of carbon dioxide in the atmosphere. Gasification is a process technology of biomass energy in a gaseous biofuel. The fuel gas got a low calorific value that can be used in diesel engine in dual mode for power generation in isolated communities. This study aimed to evaluate the reduction in the consumption of oil diesel an engine generator, using gas from gasification of wood. The engine generator brand used, it was a BRANCO, with direct injection power of 10 hp and mated to an electric generator 5,5 kW. The fuel gas was produced in a gasifier type co-current. The engine generator was put on load system from 0.5 kW to 3.5 kW through electric bank of heaters. For the oil diesel savings, the gas was injected mixed with intake air, as the oil diesel was normally injected by the injector of the engine (motor dual). The consumption od diesel was measured diesel by means of a precision scale. It was concluded that the engine converted to dual mode when using the gas for the gasification of wood showed a decrease in diesel consumption by up to 57%. (author)

Dual wavelength Mode-Locking of InAs/InP quantum dot laser diodes at 1.5µm

NARCIS (Netherlands)

Tahvili, M.S.; Heck, M.J.R.; Nötzel, R.; Smit, M.K.; Bente, E.A.J.M.

2011-01-01

We report on stable dual-wavelength mode-locking of 3.1GHz and 10GHz two-section InAs/InP(100) quantum dot laser diodes. Evaluation of relative time delay between different spectral components indicates opposite sign of chirp over the two spectral lobes

Longitudinal effects of bilingualism on dual-tasking.

Science.gov (United States)

Sörman, Daniel Eriksson; Josefsson, Maria; Marsh, John E; Hansson, Patrik; Ljungberg, Jessica K

2017-01-01

An ongoing debate surrounds whether bilinguals outperform monolinguals in tests of executive processing. The aim of this study was to investigate if there are long-term (10 year) bilingual advantages in executive processing, as indexed by dual-task performance, in a sample that were 40-65 years at baseline. The bilingual (n = 24) and monolingual (n = 24) participants were matched on age, sex, education, fluid intelligence, and study sample. Participants performed free-recall for a 12-item list in three dual-task settings wherein they sorted cards either during encoding, retrieval, or during both encoding and retrieval of the word-list. Free recall without card sorting was used as a reference to compute dual-task costs. The results showed that bilinguals significantly outperformed monolinguals when they performed card-sorting during both encoding and retrieval of the word-list, the condition that presumably placed the highest demands on executive functioning. However, dual-task costs increased over time for bilinguals relative to monolinguals, a finding that is possibly influenced by retirement age and limited use of second language in the bilingual group.

Colorimetric and Fluorescent Dual Mode Sensing of Alcoholic Strength in Spirit Samples with Stimuli-Responsive Infinite Coordination Polymers.

Science.gov (United States)

Deng, Jingjing; Ma, Wenjie; Yu, Ping; Mao, Lanqun

2015-07-07

This study demonstrates a new strategy for colorimetric and fluorescent dual mode sensing of alcoholic strength (AS) in spirit samples based on stimuli-responsive infinite coordination polymers (ICPs). The ICP supramolecular network is prepared with 1,4-bis(imidazol-1-ylmethyl)benzene (bix) as the ligand and Zn(2+) as the central metal ion in ethanol, in which rhodamine B (RhB) is encapsulated through self-adaptive chemistry. In pure ethanol solvent, the as-formed RhB/Zn(bix) is well dispersed and quite stable. However, the addition of water into the ethanol dispersion of RhB/Zn(bix) destroys Zn(bix) network structure, resulting in the release of RhB from ICP into the solvent. As a consequence, the solvent displays the color of released RhB and, at the meantime, turns on the fluorescence of RhB, which constitutes a new mechanism for colorimetric and fluorescent dual mode sensing of AS in commercial spirit samples. With the method developed here, we could distinguish the AS of different commercial spirit samples by the naked eye within a wide linear range from 20 to 100% vol and by monitoring the increase of fluorescent intensity of the released RhB. This study not only offers a new method for on-spot visible detection of AS in commercial spirit samples, but also provides a strategy for designing dual mode sensing mechanisms for different analytical purposes based on novel stimuli-responsive materials.

Analysis of Dual- and Full-Circular Polarimetric SAR Modes for Rice Phenology Monitoring: An Experimental Investigation through Ground-Based Measurements

Directory of Open Access Journals (Sweden)

Yuta Izumi

2017-04-01

Full Text Available Circularly polarized synthetic aperture radar (CP-SAR is known to be insensitive to polarization mismatch losses caused by the Faraday rotation effect and antenna misalignment. Additionally, the dual-circular polarimetric (DCP mode has proven to have more polarimetric information than that of the corresponding mode of linear polarization, i.e., the dual-linear polarimetric (DLP mode. Owing to these benefits, this paper investigates the feasibility of CP-SAR for rice monitoring. A ground-based CP-radar system was exploited, and C-band anechoic chamber data of a self-cultivated Japanese rice paddy were acquired from germination to ripening stages. Temporal variations of polarimetric observables derived from full-circular polarimetric (FCP and DCP as well as synthetically generated DLP data are analyzed and assessed with regard to their effectiveness in phenology retrieval. Among different observations, the H / α ¯ plane and triangle plots obtained by three scattering components (surface, double-bounce, and volume scattering for both the FCP and DCP modes are confirmed to have reasonable capability in discriminating the relevant intervals of rice growth.

Competition of electron-cyclotron maser and free-electron laser modes with combined solenoidal and longitudinal wiggler fields

International Nuclear Information System (INIS)

Lin, A.T.; Lin, C.

1986-01-01

A relativistic electron beam with a finite transverse dc momentum (β/sub perpendicular/ = 1/γ 0 ) passing through a region of combined uniform solenoidal and longitudinal wiggler magnetic fields is observed to convert 25% of its kinetic energy into coherent radiation at frequency ω = γ 2 0 (k/sub w/V 0 +Ω/sub c//γ 0 ) if the phase velocity of the generated wave is slightly above the speed of light. In this situation, the bunchings of the slow electron-cyclotron mode and free-electron laser modes with combined solenoidal and longitudinal wiggler fields (lowbitron) are observed to compensate each other, which gives rise to a finite threshold for lowbitron operation. In order to attain high efficiency, the wiggler strength of a lowbitron must substantially exceed the threshold

Dual-mode optical fiber-based tweezers for robust trapping and manipulation of absorbing particles in air

Science.gov (United States)

Sil, Souvik; Kanti Saha, Tushar; Kumar, Avinash; Bera, Sudipta K.; Banerjee, Ayan

2017-12-01

We develop an optical tweezers system using a single dual-mode optical fiber where mesoscopic absorbing particles can be trapped in three dimensions and manipulated employing photophoretic forces. We generate a superposition of fundamental and first order Hermite-Gaussian beam modes by the simple innovation of coupling a laser into a commercial optical fiber designed to be single mode for a wavelength higher than that of the laser. We achieve robust trapping of the absorbing particles for hours using both the pure fundamental and superposition mode beams and attain large manipulation velocities of ˜5 mm s-1 in the axial direction and ˜0.75 mm s-1 in the radial direction. We then demonstrate that the superposition mode is more effective in trapping and manipulation compared to the fundamental mode by around 80%, which may be increased several times by the use of a pure first order Hermite-Gaussian mode. The work has promising implications for trapping and spectroscopy of aerosols in air using simple optical fiber-based traps.

A Multifunctional Isolated and Non-Isolated Dual Mode Converter for Renewable Energy Conversion Applications

Directory of Open Access Journals (Sweden)

Yiwang Wang

2017-11-01

Full Text Available In this paper, a multifunctional isolated and non-isolated dual-mode low-power converter was designed for renewable energy conversion applications such as photovoltaic power generation to achieve different operating modes under bi-directional electrical conversion. The proposed topology consists of a bidirectional non-isolated DC/DC circuit and an isolated converter with a high-frequency transformer, which merge the advantages of both the conventional isolated converter and non-isolated converter with the combination of the two converter technologies. Compared with traditional converters, the multifunctional converter can not only realize conventional bi-directional functions, but can also be applied for many different operation modes and meet the high output/input ratio demands with the two converter circuits operating together. A novel control algorithm was proposed to achieve the various functions of the proposed converter. An experimental platform based on the proposed circuit was established. Both the simulation and experimental results indicated that the proposed converter could provide isolated and non-isolated modes in different applications, which could meet different practical engineering requirements.

The exercise and affect relationship: evidence for the dual-mode model and a modified opponent process theory.

Science.gov (United States)

Markowitz, Sarah M; Arent, Shawn M

2010-10-01

This study examined the relationship between exertion level and affect using the framework of opponent-process theory and the dual-mode model, with the Activation-Deactivation Adjective Checklist and the State Anxiety Inventory among 14 active and 14 sedentary participants doing 20 min of treadmill exercise at speeds of 5% below, 5% above, and at lactate threshold (LT). We found a significant effect of time, condition, Time × Condition, and Time × Group, but no group, Group × Condition, or Time × Group × Condition effects, such that the 5% above LT condition produced a worsening of affect in-task compared with all other conditions whereas, across conditions, participants experienced in-task increases in energy and tension, and in-task decreases in tiredness and calmness relative to baseline. Posttask, participants experienced mood improvement (decreased tension, anxiety, and increased calmness) across conditions, with a 30-min delay in the above LT condition. These results partially support the dual-mode model and a modified opponent-process theory.

Multi-mode vibration control of piping system

International Nuclear Information System (INIS)

Minowa, Takeshi; Seto, Kazuto; Iiyama, Fumiya; Sodeyama, Hiroshi

1999-01-01

In this paper, dual dynamic absorbers are applied to the piping system in order to control the multiple vibration modes. ANSYS, which is one of the software based on FEM(finite element method), is used for the design of dual dynamic absorbers as well as for the determination of their optimum installing positions. The dual dynamic absorbers designed optimally for controlling the first three vibration modes perform just like a houde damper in higher frequency and have an effect on controlling higher modes. To use this advantage, three dual dynamic absorbers are installed in positions where they influence higher modes, and not only the first three modes of the piping system but also the extensive modes are controlled. Practical experimental study has also been carried out and it is shown that a dual dynamic absorber is suitable for controlling the vibration of the piping system. (author)

Dual-mode switching of a liquid crystal panel for viewing angle control

Science.gov (United States)

Baek, Jong-In; Kwon, Yong-Hoan; Kim, Jae Chang; Yoon, Tae-Hoon

2007-03-01

The authors propose a method to control the viewing angle of a liquid crystal (LC) panel using dual-mode switching. To realize both wide viewing angle (WVA) characteristics and narrow viewing angle (NVA) characteristics with a single LC panel, the authors use two different dark states. The LC layer can be aligned homogeneously parallel to the transmission axis of the bottom polarizer for WVA dark state operation, while it can be aligned vertically for NVA dark state operation. The authors demonstrated that viewing angle control can be achieved with a single panel without any loss of contrast at the front.

Probing the fundamental limit of niobium in high radiofrequency fields by dual mode excitation in superconducting radiofrequency cavities

International Nuclear Information System (INIS)

Eremeev, Grigory; Geng, Rongli; Palczewski, Ari

2011-01-01

We have studied thermal breakdown in several multicell superconducting radiofrequency cavity by simultaneous excitation of two TM 010 passband modes. Unlike measurements done in the past, which indicated a clear thermal nature of the breakdown, our measurements present a more complex picture with interplay of both thermal and magnetic effects. JLab LG-1 that we studied was limited at 40.5 MV/m, corresponding to B peak = 173 mT, in 89 mode. Dual mode measurements on this quench indicate that this quench is not purely magnetic, and so we conclude that this field is not the fundamental limit in SRF cavities

High-power terahertz optical pulse generation with a dual-wavelength harmonically mode-locked Yb:YAG laser

International Nuclear Information System (INIS)

Zhuang, W Z; Chang, M T; Su, K W; Huang, K F; Chen, Y F

2013-01-01

We report on high-power terahertz optical pulse generation with a dual-wavelength harmonically mode-locked Yb:YAG laser. A semiconductor saturable absorber mirror is developed to achieve synchronously mode-locked operation at two spectral bands centered at 1031.67 and 1049.42 nm with a pulse duration of 1.54 ps and a pulse repetition rate of 80.3 GHz. With a diamond heat spreader to improve the heat removal efficiency, the average output power can be up to 1.1 W at an absorbed pump power of 5.18 W. The autocorrelation traces reveal that the mode-locked pulse is modulated with a beat frequency of 4.92 THz and displays a modulation depth to be greater than 80%. (paper)

A Comparative Study of Voltage, Peak Current and Dual Current Mode Control Methods for Noninverting Buck-Boost Converter

Directory of Open Access Journals (Sweden)

M. Č. Bošković

2016-06-01

Full Text Available This paper presents a comparison of voltage mode control (VMC and two current mode control (CMC methods of noninverting buck-boost converter. The converter control-to-output transfer function, line-to-output transfer function and the output impedance are obtained for all methods by averaging converter equations over one switching period and applying small-signal linearization. The obtained results are required for the design procedure of feedback compensator to keep a system stable and robust. A comparative study of VMC, peak current mode control (PCMC and dual-current mode control (DCMC is performed. Performance evaluation of the closed-loop system with obtained compensator between these methods is performed via numerical simulations.

Dual-mode, high energy utilization system concept for mars missions

International Nuclear Information System (INIS)

El-Genk, Mohamed S.

2000-01-01

This paper describes a dual-mode, high energy utilization system concept based on the Pellet Bed Reactor (PeBR) to support future manned missions to Mars. The system uses proven Closed Brayton Cycle (CBC) engines to partially convert the reactor thermal power to electricity. The electric power generated is kept the same during the propulsion and the power modes, but the reactor thermal power in the former could be several times higher, while maintaining the reactor temperatures almost constant. During the propulsion mode, the electric power of the system, minus ∼1-5 kW e for house keeping, is used to operate a Variable Specific Impulse Magnetoplasma Rocket (VASIMR). In addition, the reactor thermal power, plus more than 85% of the head load of the CBC engine radiators, are used to heat hydrogen. The hot hydrogen is mixed with the high temperature plasma in a VASIMR to provide both high thrust and I sp >35,000 N.s/kg, reducing the travel time to Mars to about 3 months. The electric power also supports surface exploration of Mars. The fuel temperature and the inlet temperatures of the He-Xe working fluid to the nuclear reactor core and the CBC turbine are maintained almost constant during both the propulsion and power modes to minimize thermal stresses. Also, the exit temperature of the He-Xe from the reactor core is kept at least 200 K below the maximum fuel design temperature. The present system has no single point failure and could be tested fully assembled in a ground facility using electric heaters in place of the nuclear reactor. Operation and design parameters of a 40-kW e prototype are presented and discussed to illustrate the operation and design principles of the proposed system

Research on Adaptive Dual-Mode Switch Control Strategy for Vehicle Maglev Flywheel Battery

Directory of Open Access Journals (Sweden)

Hui Gao

2015-01-01

Full Text Available Because of the jamming signal is real-time changeable and control algorithm cannot timely tracking control flywheel rotor, this paper takes vehicle maglev flywheel battery as the research object. One kind of dual-model control strategy is developed based on the analysis of the vibration response impact of the flywheel battery control system. In view of the complex foundation vibration problems of electric vehicles, the nonlinear dynamic simulation model of vehicle maglev flywheel battery is solved. Through analyzing the nonlinear vibration response characteristics, one kind of dual-mode adaptive hybrid control strategy based on H∞ control and unbalance displacement feed-forward compensation control is presented and a real-time switch controller is designed. The reliable hybrid control is implemented, and the stability in the process of real-time switch is solved. The results of this project can provide important basic theory support for the research of vehicle maglev flywheel battery control system.

A dose-per-pulse monitor for a dual-mode medical accelerator

International Nuclear Information System (INIS)

Galbraith, D.M.; Martell, E.S.; Fueurstake, T.; Norrlinger, B.; Schwendener, H.; Rawlinson, J.A.

1990-01-01

On a radiotherapy accelerator, the dose monitoring system is the last level of protection between the patient and the extremely high dose rate which all accelerators are capable of producing. The risk of losing this level of protection is substantially reduced if two or more dose monitoring systems are used which are mechanically and electrically independent in design. This paper describes the installation of an independent radiation monitor in a dual-mode, computer-controlled accelerator with a moveable monitor chamber. The added device is fixed in the beam path, is capable of monitoring each beam pulse, and is capable of terminating irradiation within the pulse repetition period if any measured pulse is unacceptably high

Compact 84 GHz passive mode-locked fiber laser using dual-fiber coupled fused-quartz microresonator

Science.gov (United States)

Liu, Tze-An; Hsu, Yung; Chow, Chi-Wai; Chuang, Yi-Chen; Ting, Wei-Jo; Wang, Bo-Chun; Peng, Jin-Long; Chen, Guan-Hong; Chang, Yuan-Chia

2017-10-01

We propose and demonstrate a compact and portable-size 84-GHz passive mode-locked fiber laser, in which a dual-fiber coupled fused-quartz microresonator is employed as the intracavity optical comb filter as well as the optical nonlinear material for optical frequency comb generation. About eight coherent optical tones can be generated in the proposed fiber laser. The 20-dB bandwidth is larger than 588 GHz. The full-width half-maximum pulse-width of the proposed laser is 2.5 ps. We also demonstrate the feasibility of using the proposed passive mode-locked fiber laser to carry a 5-Gbit/s on-off-keying signal and transmit over 20-km standard single mode fiber. A 7% forward error correction requirement can be achieved, showing the proposed fiber laser can be a potential candidate for fiber-wireless applications.

A novel detector based on dual-mode fiber polished half block's characteristics for sensitive monitorings of radiation and materials

International Nuclear Information System (INIS)

Saeed, Ghadirli

2005-01-01

Full text : The overlay index dependence characteristics of the power distribution between two modes of dual-mode fiber polished half blocks is studied. The heat dependence characteristics of a certain overlay index affects the modal power distributions at the input of interferometer sensors used for monitoring the sensitive heat radiation changes. The other fundamental applications such as material recognitions through the index dependence characteristics in the closed chambers is also suggested

Designing a dual-mode broadband solar spectral converter: The example of Bi{sup 3+}, Cr{sup 3+}, Yb{sup 3+}-tridoped perovskite

Energy Technology Data Exchange (ETDEWEB)

Lin, Li-Tian; Wu, Xuan-Ming; Wang, Ting; Chen, Dong-Ju; Deng, Chao; Meng, Jian-Xin, E-mail: tmjx@jnu.edu.cn; Cao, Li-Wei

2016-07-15

A promising dual-mode broadband solar spectral converter CaTiO{sub 3}: Bi{sup 3+}, Cr{sup 3+}, Yb{sup 3+} was successfully developed by solid-stated reaction. The structure, photoluminescence (PL), photoluminescence excitation (PLE) and diffuse reflectance (DR) spectra in the UV–vis–NIR region have been systematically investigated. The results show that the as-prepared samples simultaneously exhibit two distinct spectral converting patterns, nonlinear quantum-cutting (QC) involving Bi{sup 3+}–Ti{sup 4+} metal-to-metal charge transfer state (BT-MMCTs) → Yb{sup 3+}: {sup 2}F{sub 5/2} + Yb{sup 3+}: {sup 2}F{sub 5/2} and linear downshift (DS) involving Cr{sup 3+}: {sup 4}T{sub 2} → Yb{sup 3+}: {sup 2}F{sub 5/2}. It deduces that the nonlinear QC is based on a cooperative energy transfer (CET) process while the linear DS belongs to a dipole–dipole mechanism. With the present converter, broadband UV–vis (300–700 nm) photons, which are not fully utilized by the existing c-Si solar cells, can be efficiently harvested and converted into ∼1000 nm NIR photons via the dual-mode mechanism. Moreover, not only the PLE spectrum of CaTiO{sub 3}: Bi{sup 3+}, Cr{sup 3+}, Yb{sup 3+} matched well with that of the solar radiation, but also its NIR emission peak position fell well over the spectral response of the commercial crystalline Si (c-Si) solar cells. This as-prepared dual-mode solar spectral converter with multiple advantages can simultaneously realize high quantum yield and broadband conversion, which offers a new and effective way to boost the conversion efficiency of c-Si solar cells. We believe this novel design of dual-mode solar spectral converters can inspire a direction for the synthesis of more advanced UV–vis–NIR phosphors that can be used in Si solar cells. - Highlights: • A dual-mode broadband solar spectral converter is designed and developed. • The energy transfer mechanism relies on quantum-cutting as well as downshift. • The PLE

Research on a six-phase permanent magnet synchronous motor system at dual-redundant and fault tolerant modes in aviation application

Directory of Open Access Journals (Sweden)

Xiaolin KUANG

2017-08-01

Full Text Available With the development of more/all electrical aircraft technology, an electro-mechanical actuator (EMA is more and more used in an aircraft actuation system. The motor system, as the crucial part of an EMA, usually adopts the redundancy technology or fault tolerance technology to improve the reliability. To compare the performances of these two motor systems, a 10-pole/12-slot six-phase permanent magnet synchronous motor (PMSM is designed with the concentrated single-layer winding, which is able to operate at dual-redundant and fault tolerant modes. Furthermore, the position servo performances of the six-phase PMSM at dual-redundant and fault tolerant modes are analyzed, including the normal and fault conditions. In addition, a variable structure proportional-integral-derivative (PID control strategy is proposed to solve the performance degradation problem caused by phase current saturation. Simulation and experimental results show that the fault tolerant PMSM has a better position servo performance than the dual-redundant PMSM, and the variable structure PID control strategy is able to improve the performance due to phase current saturation.

Design and multifidelity analysis of dual mode scramjet compression system using coupled NPSS and fluent simulation

Science.gov (United States)

Vijayakumar, Nandakumar

Hypersonic airbreathing engines mark a potential future development of the aerospace industry and immense efforts have been taken in gaining knowledge in them for the past decades. The physical phenomenon occurring at the hypersonic flow regime makes the design and performance prediction of a scramjet engine hard. Though cutting-edge simulation tools fight their way toward accurate prediction of the environment, the time consumed by the entire process in designing and analyzing a scramjet engine and its component may be exorbitant. A multi-fidelity approach for designing a scramjet with a cruising Mach number of 6 is detailed in this research where high-order simulations are applied according to the physics involved in the component. Two state-of-the-art simulation tools were used to take the aerodynamic and propulsion disciplines into account for realistic prediction of the individual components as well as the entire scramjet. The specific goal of this research is to create a virtual environment to design and analyze a hypersonic, two-dimensional, planar inlet and isolator to check its operability for a dual-mode scramjet engine. The dual mode scramjet engine starts at a Mach number of 3.5 where it operates as a ramjet and accelerates to Mach 6 to be operated as a scramjet engine. The intercomponent interaction between the compression components with the rest of the engine is studied by varying the fidelity of the numerical simulation according to the complexity of the situation. Efforts have been taken to track the transition Mach number as it switches from ramjet to scramjet. A complete scramjet assembly was built using the Numerical Propulsion Simulation System (NPSS) and the performance of the engine was evaluated for various scenarios. Different numerical techniques were opted for varying the fidelity of the analysis with the highest fidelity consisting of 2D RANS CFD simulation. The interaction between the NPSS elements with the CFD solver is governed by the

Sistim Tampilan Jadwal Pesawat Udara Dengan Mode Dual Display Di Bandara Ahmad Yani Semarang

Directory of Open Access Journals (Sweden)

Hari Suseno

2014-02-01

Full Text Available Schedule for airline passengers is important information that is provided by the airport manager. Airport flight information on the display screen using a media schedule called flight information display system (FIDS. FIDS system comes from two processes that display arrival and departure information. The device comes from the appearance of two separate computer with information for each. The use of two computers that are used to the old system at the airport FIDS devices. This research aims to create an integrated FIDS system device to combine the information into one unified display in dual display mode pattern display (dual view. Design systems using software programming VB6 and hardware modifications applied to design a system FIDS new on view flight schedules. With a centralized system obtained an interactive display schedules for flight schedule. Keywords : FIDS system; Flight schedule; Display  information

Giant Gold Nanowire Vesicle-Based Colorimetric and SERS Dual-Mode Immunosensor for Ultrasensitive Detection of Vibrio parahemolyticus.

Science.gov (United States)

Guo, Zhiyong; Jia, Yaru; Song, Xinxin; Lu, Jing; Lu, Xuefei; Liu, Baoqing; Han, Jiaojiao; Huang, Youju; Zhang, Jiawei; Chen, Tao

2018-05-15

Conventional methods for the detection of Vibrio parahemolyticus (VP) usually need tedious, labor-intensive processes, and have low sensitivity, which further limits their practical applications. Herein, we developed a simple and efficient colorimetry and surface-enhanced Raman scattering (SERS) dual-mode immunosensor for sensitive detection of VP, by employing giant Au vesicles with anchored tiny gold nanowires (AuNW) as a smart probe. Due to the larger specific surface and special hollow structure of giant Au vesicles, silver staining would easily lead to vivid color change for colorimetric analysis and further amplify SERS signals. The t-test was further used to determine if two sets of data from colorimetry and SERS were significantly different from each other. The result shows that there was no significant difference between data from the two methods. Two sets of data can mutually validate each other and avoid false positive and negative detection. The designed colorimetry-SERS dual-mode sensor would be very promising in various applications such as food safety inspection, personal healthcare, and on-site environmental monitoring.

Dual-wavelength passive and hybrid mode-locking of 3, 4.5 and 10 GHz InAs/InP(100) quantum dot lasers

NARCIS (Netherlands)

Tahvili, M.S.; Du, L.; Heck, M.J.R.; Nötzel, R.; Smit, M.K.; Bente, E.A.J.M.

2012-01-01

We present an investigation of passive and hybrid mode-locking in Fabry-Pérot type two-section InAs/InP(100) quantum dot lasers that show dual wavelength operation. Over the whole current and voltage range for mode-locking of these lasers, the optical output spectra show two distinct lobes. The two

Dual mode antibacterial activity of ion substituted calcium phosphate nanocarriers for bone infections

Directory of Open Access Journals (Sweden)

Sampath Kumar eT.S.

2015-05-01

Full Text Available Nanotechnology has tremendous potential for the management of infectious diseases caused by multi-drug resistant (MDR bacteria, through the development of newer antibacterial materials and efficient modes of antibiotic delivery. Calcium phosphate (CaP bioceramics are commonly used as bone substitutes due to their similarity to bone mineral and are widely researched upon for the treatment of bone infections associated with bone loss. CaPs can be used as local antibiotic delivery agents for bone infections and can be substituted with antibacterial ions in their crystal structure to have a wide spectrum, sustained antibacterial activity even against drug resistant bacteria. In the present work, a dual mode antibiotic delivery system with antibacterial ion substituted calcium deficient hydroxyapatite (CDHA nanoparticles has been developed. Antibacterial ions such as zinc, silver and strontium have been incorporated into CDHA at concentrations of 6 at. %, 0.25-0.75 at. % and 2.5-7.5 at. % respectively. The samples were found to be phase pure, acicular nanoparticles of length 40-50 nm and width 5-6 nm approximately. The loading and release profile of doxycycline, a commonly used antibiotic, was studied from the nanocarriers. The drug release was studied for five days and the release profile was influenced by the ion concentrations. The release of antibacterial ions was studied over a period of 21 days. The ion substituted CDHA samples were tested for antibacterial efficacy on S.aureus and E.coli by MIC/MBC studies and time-kill assay. AgCDHA and ZnCDHA showed high antibacterial activity against both bacteria while SrCDHA was weakly active against S.aureus. Present study shows that the antibiotic release can provide the initial high antibacterial activity and the sustained ion release can provide a long-term antibacterial activity. Such dual mode antibiotic and antibacterial ion release offers an efficient and potent way to treat an incumbent drug

The dual of the Carroll-Field-Jackiw model

International Nuclear Information System (INIS)

Guimaraes, M.S.; Grigorio, L.; Wotzasek, C.

2006-01-01

In this work we apply different duality techniques, both the dual projection, based on the soldering formalism and the master action, in order to obtain and study the dual description of the Carroll- Field-Jackiw model [1], a theory with a Chern-Simons-like explicitly Lorentz and CPT violating term, including the interaction with external charges. This Maxwell-Chern-Simons-like model may be rewritten in terms of the interacting modes of a massless scalar model and a topologically massive model [2], that are mapped, through duality, into interacting massless Maxwell and massive self-dual modes [3]. It is also shown that these dual modes might be represented into an unified rank-two self-dual model that represents the direct dual of the vector Maxwell-Chern-Simons-like model

PERFORMANCE, EMISSION, AND COMBUSTION CHARACTERISTICS OF A CI ENGINE USING LIQUID PETROLEUM GAS AND NEEM OIL IN DUAL FUEL MODE

Directory of Open Access Journals (Sweden)

Palanimuthu Vijayabalan

2010-01-01

Full Text Available Increased environmental awareness and depletion of resources are driving the industries to develop viable alternative fuels like vegetable oils, compresed natural gas, liquid petroleum gas, producer gas, and biogas in order to provide suitable substitute to diesel for compression ignition engine. In this investigation, a single cylinder, vertical, air-cooled diesel engine was modified to use liquid petroleum gas in dual fuel mode. The liquefied petroleum gas, was mixed with air and supplied through intake manifold. The liquid fuel neem oil or diesel was injected into the combustion chamber. The performance, emission, and combustion characteristics were studied and compared for neat fuel and dual fuel mode. The experimental results on dual fuel engine show a reduction in oxides of nitrogen up to 70% of the rated power and smoke in the entire power range. However the brake thermal efficiency was found decreased in low power range due to lower calorific value of liquid petroleum gas, and increase in higher power range due to the complete burning of liquid petroleum gas. Hydrocarbon and carbon monoxide emissions were increased significantly at lower power range and marginal variation in higher power range.

Dual-mode nested search method for categorical uncertain multi-objective optimization

Science.gov (United States)

Tang, Long; Wang, Hu

2016-10-01

Categorical multi-objective optimization is an important issue involved in many matching design problems. Non-numerical variables and their uncertainty are the major challenges of such optimizations. Therefore, this article proposes a dual-mode nested search (DMNS) method. In the outer layer, kriging metamodels are established using standard regular simplex mapping (SRSM) from categorical candidates to numerical values. Assisted by the metamodels, a k-cluster-based intelligent sampling strategy is developed to search Pareto frontier points. The inner layer uses an interval number method to model the uncertainty of categorical candidates. To improve the efficiency, a multi-feature convergent optimization via most-promising-area stochastic search (MFCOMPASS) is proposed to determine the bounds of objectives. Finally, typical numerical examples are employed to demonstrate the effectiveness of the proposed DMNS method.

Realization of Current Mode Universal Filter and a Dual-Mode Single Resistance Controlled Quadrature Oscillator Employing VDCC and Only Grounded Passive Elements

Directory of Open Access Journals (Sweden)

Manish Gupta

2017-01-01

Full Text Available The manuscript presents a circuit that can act as a universal filter as well as a single resistence controlled oscillator by unpretentiously changing the switch positions. The circuit employs only two active devices and all grounded passive elements. The utilization of only grounded passive components makes this circuit a better choice for integrated circuit implementation. The current mode biquadratic filter offers all the five basic responses along with independent tunability of its quality factor. The dual-mode quadrature sinusoidal oscillator offers explicit current outputs along with voltage outputs. The circuit also offers a simple and uncoupled condition of oscillation and frequency of oscillation. The typical analysis such as non-ideal, sensitivity and parasitic analysis along with the regular simulation results as well as experimental results are exposed here, to strengthen the design idea.

In situ, dual-mode monitoring of organ-on-a-chip with smartphone-based fluorescence microscope.

Science.gov (United States)

Cho, Soohee; Islas-Robles, Argel; Nicolini, Ariana M; Monks, Terrence J; Yoon, Jeong-Yeol

2016-12-15

The use of organ-on-a-chip (OOC) platforms enables improved simulation of the human kidney's response to nephrotoxic drugs. The standard method of analyzing nephrotoxicity from existing OOC has majorly consisted of invasively collecting samples (cells, lysates, media, etc.) from an OOC. Such disruptive analyses potentiate contamination, disrupt the replicated in vivo environment, and require expertize to execute. Moreover, traditional analyses, including immunofluorescence microscopy, immunoblot, and microplate immunoassay are essentially not in situ and require substantial time, resources, and costs. In the present work, the incorporation of fluorescence nanoparticle immunocapture/immunoagglutination assay into an OOC enabled dual-mode monitoring of drug-induced nephrotoxicity in situ. A smartphone-based fluorescence microscope was fabricated as a handheld in situ monitoring device attached to an OOC. Both the presence of γ-glutamyl transpeptidase (GGT) on the apical brush-border membrane of 786-O proximal tubule cells within the OOC surface, and the release of GGT to the outflow of the OOC were evaluated with the fluorescence scatter detection of captured and immunoagglutinated anti-GGT conjugated nanoparticles. This dual-mode assay method provides a novel groundbreaking tool to enable the internal and external in situ monitoring of the OOC, which may be integrated into any existing OOCs to facilitate their subsequent analyses. Copyright © 2016 Elsevier B.V. All rights reserved.

Dual-mode optical microscope based on single-pixel imaging

Science.gov (United States)

Rodríguez, A. D.; Clemente, P.; Tajahuerce, E.; Lancis, J.

2016-07-01

We demonstrate an inverted microscope that can image specimens in both reflection and transmission modes simultaneously with a single light source. The microscope utilizes a digital micromirror device (DMD) for patterned illumination altogether with two single-pixel photosensors for efficient light detection. The system, a scan-less device with no moving parts, works by sequential projection of a set of binary intensity patterns onto the sample that are codified onto a modified commercial DMD. Data to be displayed are geometrically transformed before written into a memory cell to cancel optical artifacts coming from the diamond-like shaped structure of the micromirror array. The 24-bit color depth of the display is fully exploited to increase the frame rate by a factor of 24, which makes the technique practicable for real samples. Our commercial DMD-based LED-illumination is cost effective and can be easily coupled as an add-on module for already existing inverted microscopes. The reflection and transmission information provided by our dual microscope complement each other and can be useful for imaging non-uniform samples and to prevent self-shadowing effects.

Terminalia Chebula provides protection against dual modes of necroptotic and apoptotic cell death upon death receptor ligation.

Science.gov (United States)

Lee, Yoonjung; Byun, Hee Sun; Seok, Jeong Ho; Park, Kyeong Ah; Won, Minho; Seo, Wonhyoung; Lee, So-Ra; Kang, Kidong; Sohn, Kyung-Cheol; Lee, Ill Young; Kim, Hyeong-Geug; Son, Chang Gue; Shen, Han-Ming; Hur, Gang Min

2016-04-27

Death receptor (DR) ligation elicits two different modes of cell death (necroptosis and apoptosis) depending on the cellular context. By screening a plant extract library from cells undergoing necroptosis or apoptosis, we identified a water extract of Terminalia chebula (WETC) as a novel and potent dual inhibitor of DR-mediated cell death. Investigation of the underlying mechanisms of its anti-necroptotic and anti-apoptotic action revealed that WETC or its constituents (e.g., gallic acid) protected against tumor necrosis factor-induced necroptosis via the suppression of TNF-induced ROS without affecting the upstream signaling events. Surprisingly, WETC also provided protection against DR-mediated apoptosis by inhibition of the caspase cascade. Furthermore, it activated the autophagy pathway via suppression of mTOR. Of the WETC constituents, punicalagin and geraniin appeared to possess the most potent anti-apoptotic and autophagy activation effect. Importantly, blockage of autophagy with pharmacological inhibitors or genetic silencing of Atg5 selectively abolished the anti-apoptotic function of WETC. These results suggest that WETC protects against dual modes of cell death upon DR ligation. Therefore, WETC might serve as a potential treatment for diseases characterized by aberrantly sensitized apoptotic or non-apoptotic signaling cascades.

Electromyographic evaluation of the upper lip according to the breathing mode: a longitudinal study

Directory of Open Access Journals (Sweden)

Aldrieli Regina Ambrosio

2009-12-01

Full Text Available The present study aimed at analyzing and comparing longitudinally the EMG (electromyographic activity of the superior orbicularis oris muscle according to the breathing mode. The sample, 38 adolescents with Angle Class II Division 1 malocclusion with predominantly nose (PNB or mouth (PMB breathing, was evaluated at two different periods, with a two-year interval between them. For that purpose, a 16channel electromyography machine was employed, which was properly calibrated in a PC equipped with an analogue-digital converter, with utilization of surface, passive and bipolar electrodes. The RMS data (root mean square were collected at rest and in 12 movements and normalized according to time and amplitude, by the peak value of EMG, in order to allow comparisons between subjects and between periods. Comparison of the muscle function of PNB and PMB subjects at period 1 (P1, period 2 (P2 and the variation between periods (Δ did not reveal statistically significant differences between groups (p < 0.05. However, longitudinal evaluation of the muscle function in PNB and PMB subjects demonstrated different evolutions in the percentage of required EMG for accomplishment of the movements investigated. It was possible to conclude that there are differences in the percentage of electric activity of the upper lip with the growth of the subjects according to the breathing mode.

The effects of voice and manual control mode on dual task performance

Science.gov (United States)

Wickens, C. D.; Zenyuh, J.; Culp, V.; Marshak, W.

1986-01-01

Two fundamental principles of human performance, compatibility and resource competition, are combined with two structural dichotomies in the human information processing system, manual versus voice output, and left versus right cerebral hemisphere, in order to predict the optimum combination of voice and manual control with either hand, for time-sharing performance of a dicrete and continuous task. Eight right handed male subjected performed a discrete first-order tracking task, time-shared with an auditorily presented Sternberg Memory Search Task. Each task could be controlled by voice, or by the left or right hand, in all possible combinations except for a dual voice mode. When performance was analyzed in terms of a dual-task decrement from single task control conditions, the following variables influenced time-sharing efficiency in diminishing order of magnitude, (1) the modality of control, (discrete manual control of tracking was superior to discrete voice control of tracking and the converse was true with the memory search task), (2) response competition, (performance was degraded when both tasks were responded manually), (3) hemispheric competition, (performance degraded whenever two tasks were controlled by the left hemisphere) (i.e., voice or right handed control). The results confirm the value of predictive models invoice control implementation.

Subdiffraction-limited imaging based on longitudinal modes in a spatially dispersive slab

Science.gov (United States)

Yanai, Avner; Levy, Uriel

2014-08-01

It was proposed that a flat silver layer could be used to form a subdiffraction-limited image when illuminated near its surface plasmon resonance frequency [J. B. Pendry, Phys. Rev. Lett. 85, 3966 (2000), 10.1103/PhysRevLett.85.3966]. In this paper, we study the possibility of obtaining sub diffraction resolution using a different mechanism, with no surface plasmons involved. Instead, by taking into account the nonlocal response of a thin silver slab, we show that longitudinal modes contribute to the formation of a subdiffraction-limited image in a frequency regime above the plasma frequency. The differences between these two distinct mechanisms are studied and explained.

Dual-Mode Measurement and Theoretical Analysis of Evaporation Kinetics of Binary Mixtures

Science.gov (United States)

Song, Hanyu; He, Chi-Ruei; Basdeo, Carl; Li, Ji-Qin; Ye, Dezhuang; Kalonia, Devendra; Li, Si-Yu; Fan, Tai-Hsi

Theoretical and experimental investigations are presented for the precision measurement of evaporation kinetics of binary mixtures using a quartz crystal resonator. A thin layer of light alcohol mixture including a volatile (methanol) and a much less volatile (1-butanol) components is deployed on top of the resonator. The normal or acoustic mode is to detect the moving liquid-vapor interface due to evaporation with a great spatial precision on the order of microns, and simultaneously the shear mode is used for in-situ detection of point viscosity or concentration of the mixture near the resonator. A one-dimensional theoretical model is developed to describe the underlying mass transfer and interfacial transport phenomena. Along with the modeling results, the transient evaporation kinetics, moving interface, and the stratification of viscosity of the liquid mixture during evaporation are simultaneously measured by the impedance response of the shear and longitudinal waves emitted from the resonator. The system can be used to characterize complicated evaporation kinetics involving multi-component fuels. American Chemical Society Petroleum Research Fund, NSF CMMI-0952646.

Modes of storage ring coherent instabilities

Energy Technology Data Exchange (ETDEWEB)

Wang, J.M.

1986-12-01

Longitudinal impedance in a beam and various modes of longitudinal coherent instabilities are discussed. The coasting beam coherent instability, microwave instability, and single-bunch longitudinal coherent instabilities are considered. The Vlasov equation is formulated, and a method of solving it is developed. The synchrotron modes are treated, which take the possible bunch shape distortion fully into consideration. A method of treating the synchrotron mode coupling in the case of a small bunch is discussed which takes advantage of the fact that only a few of the synchrotron modes can contribute in such a case. The effect of many bunches on the coherent motion of the beam and the longitudinal symmetric coupled bunch modes are discussed. The transverse impedance is then introduced, and the transverse coasting beam instability is discussed. Various bunched beam instabilities are discussed, including both single bunch instabilities and coupled bunch instabilities. The Vlasov equation for transverse as well as longitudinal motion of particles is introduced as well as a method of solving it within a linear approximation. Head-tail modes and short bunch instabilities and strong coupling instabilities in the long bunch case are covered. (LEW)

Modes of storage ring coherent instabilities

International Nuclear Information System (INIS)

Wang, J.M.

1986-12-01

Longitudinal impedance in a beam and various modes of longitudinal coherent instabilities are discussed. The coasting beam coherent instability, microwave instability, and single-bunch longitudinal coherent instabilities are considered. The Vlasov equation is formulated, and a method of solving it is developed. The synchrotron modes are treated, which take the possible bunch shape distortion fully into consideration. A method of treating the synchrotron mode coupling in the case of a small bunch is discussed which takes advantage of the fact that only a few of the synchrotron modes can contribute in such a case. The effect of many bunches on the coherent motion of the beam and the longitudinal symmetric coupled bunch modes are discussed. The transverse impedance is then introduced, and the transverse coasting beam instability is discussed. Various bunched beam instabilities are discussed, including both single bunch instabilities and coupled bunch instabilities. The Vlasov equation for transverse as well as longitudinal motion of particles is introduced as well as a method of solving it within a linear approximation. Head-tail modes and short bunch instabilities and strong coupling instabilities in the long bunch case are covered

Dual-channel amplification in a single-mode diode laser for multi-isotope laser cooling

International Nuclear Information System (INIS)

Booth, James L.; Van Dongen, Janelle; Lebel, Paul; Klappauf, Bruce G.; Madison, Kirk W.

2007-01-01

The output from two grating-stabilized external-cavity diode lasers were injected into a single-mode diode laser. Operating at a wavelength of 780 nm, this laser produced ∼50 mW of power with two main frequency components of the same spectral characteristics of the seed lasers. The power ratio of the amplified components was freely adjustable due to gain saturation, and amplification was observed for frequency differences of the two seed lasers in the range from 73 MHz to 6.6 GHz. This system was used to realize a dual isotope magneto-optic trap (MOT) for rubidium ( 85 Rb and 87 Rb). The resulting position and cloud size of the dual isotope MOT was the same as that of the single species MOTs to within ±10 and ±20 μm, respectively. We also characterized the additional spectral components produced by four wave mixing (FWM) in the diode laser amplifier and utilized a particular FWM sideband to realize hyperfine pumping and subsequent laser trapping of 85 Rb in the absence of a 'repump' laser dedicated to hyperfine pumping

Feasibility of a dual regime gyrotron

International Nuclear Information System (INIS)

Sawant, Ashwini; Jain, Prerit; Kartikeyan, M.V.

2012-01-01

The design concept of a 42/84 GHz, 500 kW, CW, dual-regime gyrotron for ECRH of plasma in an experimental Tokamak will be presented in this paper. Operation at 42 GHz is fundamental where as that in 84 GHz will be second harmonic so that a similar guidance system will be retained for dual regime operation. In this paper, the mode competition and mode selection procedures are presented for such a dual regime operation. Cold cavity design and self-consistent calculations will be carried out for power and efficiencies. (author)

Decentralized Sliding Mode Observer Based Dual Closed-Loop Fault Tolerant Control for Reconfigurable Manipulator against Actuator Failure

Science.gov (United States)

Zhao, Bo; Li, Yuanchun

2015-01-01

This paper considers a decentralized fault tolerant control (DFTC) scheme for reconfigurable manipulators. With the appearance of norm-bounded failure, a dual closed-loop trajectory tracking control algorithm is proposed on the basis of the Lyapunov stability theory. Characterized by the modularization property, the actuator failure is estimated by the proposed decentralized sliding mode observer (DSMO). Moreover, the actuator failure can be treated in view of the local joint information, so its control performance degradation is independent of other normal joints. In addition, the presented DFTC scheme is significantly simplified in terms of the structure of the controller due to its dual closed-loop architecture, and its feasibility is highly reflected in the control of reconfigurable manipulators. Finally, the effectiveness of the proposed DFTC scheme is demonstrated using simulations. PMID:26181826

Decentralized Sliding Mode Observer Based Dual Closed-Loop Fault Tolerant Control for Reconfigurable Manipulator against Actuator Failure.

Directory of Open Access Journals (Sweden)

Bo Zhao

Full Text Available This paper considers a decentralized fault tolerant control (DFTC scheme for reconfigurable manipulators. With the appearance of norm-bounded failure, a dual closed-loop trajectory tracking control algorithm is proposed on the basis of the Lyapunov stability theory. Characterized by the modularization property, the actuator failure is estimated by the proposed decentralized sliding mode observer (DSMO. Moreover, the actuator failure can be treated in view of the local joint information, so its control performance degradation is independent of other normal joints. In addition, the presented DFTC scheme is significantly simplified in terms of the structure of the controller due to its dual closed-loop architecture, and its feasibility is highly reflected in the control of reconfigurable manipulators. Finally, the effectiveness of the proposed DFTC scheme is demonstrated using simulations.

Large-area, uniform and low-cost dual-mode plasmonic naked-eye colorimetry and SERS sensor with handheld Raman spectrometer.

Science.gov (United States)

Xu, Zhida; Jiang, Jing; Wang, Xinhao; Han, Kevin; Ameen, Abid; Khan, Ibrahim; Chang, Te-Wei; Liu, Gang Logan

2016-03-21

We demonstrated a highly-sensitive, wafer-scale, highly-uniform plasmonic nano-mushroom substrate based on plastic for naked-eye plasmonic colorimetry and surface-enhanced Raman spectroscopy (SERS). We gave it the name FlexBrite. The dual-mode functionality of FlexBrite allows for label-free qualitative analysis by SERS with an enhancement factor (EF) of 10(8) and label-free quantitative analysis by naked-eye colorimetry with a sensitivity of 611 nm RIU(-1). The SERS EF of FlexBrite in the wet state was found to be 4.81 × 10(8), 7 times stronger than in the dry state, making FlexBrite suitable for aqueous environments such as microfluid systems. The label-free detection of biotin-streptavidin interaction by both SERS and colorimetry was demonstrated with FlexBrite. The detection of trace amounts of the narcotic drug methamphetamine in drinking water by SERS was implemented with a handheld Raman spectrometer and FlexBrite. This plastic-based dual-mode nano-mushroom substrate has the potential to be used as a sensing platform for easy and fast analysis in chemical and biological assays.

Dual-mode endomicroscopy for detection of epithelial dysplasia in the mouth: a descriptive pilot study

Science.gov (United States)

Bodenschatz, Nico; Poh, Catherine F.; Lam, Sylvia; Lane, Pierre; Guillaud, Martial; MacAulay, Calum E.

2017-08-01

Dual-mode endomicroscopy is a diagnostic tool for early cancer detection. It combines the high-resolution nuclear tissue contrast of fluorescence endomicroscopy with quantified depth-dependent epithelial backscattering as obtained by diffuse optical microscopy. In an in vivo pilot imaging study of 27 oral lesions from 21 patients, we demonstrate the complementary diagnostic value of both modalities and show correlations between grade of epithelial dysplasia and relative depth-dependent shifts in light backscattering. When combined, the two modalities provide diagnostic sensitivity to both moderate and severe epithelial dysplasia in vivo.

A Dual-Mode UWB Wireless Platform with Random Pulse Length Detection for Remote Patient Monitoring

DEFF Research Database (Denmark)

Reyes, Carlos; Bisbe, Sergi; Shen, Ming

2013-01-01

on a single hardware platform, but it is capable of both monitoring and data transmission. This is achieved by employing a new random pulse length detection method that allows data transmission by using a modulated monitoring signal. To prove the proposed concept a test system has been built, using commercial......This paper presents a dual-mode ultra-wideband platform for wireless Remote Patient Monitoring (RPM). Existing RPM solutions are typically based on two different hardware platforms; one responsible for medical-data monitoring and one to handle data transmission. The proposed RPM topology is based...

Highly coherent free-running dual-comb chip platform.

Science.gov (United States)

Hébert, Nicolas Bourbeau; Lancaster, David G; Michaud-Belleau, Vincent; Chen, George Y; Genest, Jérôme

2018-04-15

We characterize the frequency noise performance of a free-running dual-comb source based on an erbium-doped glass chip running two adjacent mode-locked waveguide lasers. This compact laser platform, contained only in a 1.2 L volume, rejects common-mode environmental noise by 20 dB thanks to the proximity of the two laser cavities. Furthermore, it displays a remarkably low mutual frequency noise floor around 10  Hz 2 /Hz, which is enabled by its large-mode-area waveguides and low Kerr nonlinearity. As a result, it reaches a free-running mutual coherence time of 1 s since mode-resolved dual-comb spectra are generated even on this time scale. This design greatly simplifies dual-comb interferometers by enabling mode-resolved measurements without any phase lock.

Highly optimized tunable Er3+-doped single longitudinal mode fiber ring laser, experiment and model

DEFF Research Database (Denmark)

Poulsen, Christian; Sejka, Milan

1993-01-01

A continuous wave (CW) tunable diode-pumped Er3+-doped fiber ring laser, pumped by diode laser at wavelengths around 1480 nm, is discussed. Wavelength tuning range of 42 nm, maximum slope efficiency of 48% and output power of 14.4 mW have been achieved. Single longitudinal mode lasing...... with a linewidth of 6 kHz has been measured. A fast model of erbium-doped fiber laser was developed and used to optimize output parameters of the laser...

Robust equivalent consumption-based controllers for a dual-mode diesel parallel HEV

International Nuclear Information System (INIS)

Finesso, Roberto; Spessa, Ezio; Venditti, Mattia

2016-01-01

Highlights: • Non-plug-in dual-mode parallel hybrid architecture. • Cross-validation machine-learning for robust equivalent consumption-based controllers. • Optimal control strategy based on fuel consumption, NOx and battery aging. • Impact of different equivalent consumption definitions on HEV performance. • Correlation between vehicle braking energy and SOC variation in the traction stages. - Abstract: New equivalent consumption minimization strategy (ECMS) tools have been developed and applied to identify the optimal control strategy of a dual-mode parallel hybrid electric vehicle equipped with a compression-ignition engine. In this architecture, the electric machine is coupled to the engine through either a single-speed gearbox (torque-coupling) or a planetary gear set (speed-coupling). One of the main novelties of the present study concerns the definition of the instantaneous equivalent consumption (EC) function, which takes into account not only fuel consumption (FC) and the energy flow through the electric components, but also NO_x emissions, battery aging, and the battery SOC. The EC function has been trained using a cross-validation machine-learning technique, based on a genetic algorithm, where the training data set has been selected in order to maximize performances over a testing data set. The adoption of this technique, in conjunction with the new definition of EC, have led to the identification of very robust controllers, which provide an accurate control for different driving scenarios, even when the EC function is not specifically trained on the same missions over which it is tested. To this aim, a data set of fifty driving cycles and six user-defined missions, which cover a total distance of 70–100 km, has been considered as a training driving set. The ECMS controllers can be implemented in a vehicle control unit, and their performance has resulted to be close to that of a dynamic programming tool, which has here been used as benchmark

Single-longitudinal mode distributed-feedback fiber laser with low-threshold and high-efficiency

Science.gov (United States)

Jiang, Man; Zhou, Pu; Gu, Xijia

2018-01-01

Single-frequency fiber laser has attracted a lot of interest in recent years due to its numerous application potentials in telecommunications, LIDAR, high resolution sensing, atom frequency standard, etc. Phosphate glass fiber is one of the candidates for building compact high gain fiber lasers because of its capability of high-concentration of rare-earth ions doping in fiber core. Nevertheless, it is challenging for the integration of UV-written intra-core fiber Bragg gratings into the fiber laser cavity due to the low photosensitivity of phosphate glass fiber. The research presented in this paper will focus on demonstration of UV-written Bragg gratings in phosphate glass fiber and its application in direct-written short monolithic single-frequency fiber lasers. Strong π-phase shift Bragg grating structure is direct-inscribed into the Er/Yb co-doped gain fiber using an excimer laser, and a 5-cm-long phase mask is used to inscribe a laser cavity into the Er/Yb co-doped phosphate glass fibers. The phase mask is a uniform mask with a 50 μm gap in the middle. The fiber laser device emits output power of 10.44 mW with a slope efficiency of 21.5% and the threshold power is about 42.8 mW. Single-longitudinal mode operation is validated by radio frequency spectrum measurement. Moreover, the output spectrum at the highest power shows an excellent optical signal to noise ratio of about 70 dB. These results, to the best of our knowledge, show the lowest power threshold and highest efficiency among the reports that using the same structure to achieve single-longitudinal mode laser output.

Multi-electrode laterally coupled distributed feedback InGaAsP/InP lasers: a prescription for longitudinal mode control

Science.gov (United States)

Benhsaien, Abdessamad; Dridi, Kais; Zhang, Jessica; Hall, Trevor J.

2013-10-01

Photonic Integrated Circuits (PICs) enable photons as data carriers at a very high speed. PIC market opportunities call for reduced wafer dimensions, power consumption and cost as well as enhanced reliability. The PIC technology development must cater for the latter relentless traits. In particular, monolithic PICs are sought as they can integrate hundreds of components and functions onto a single chip. InGaAsP/InP laterally-coupled distributed feedback (LC-DFB) lasers stand as key enablers in the PIC technology thanks to the compelling advantages their embedded high-order surface-gratings have. The patterning of the spatial corrugation along the sidewalls of the LC-DFB ridge, has been established to make the epitaxial overgrowth unnecessary thereby reducing the cost and time of manufacturing, and ultimately increasing the yield. LC-DFBs boast a small footprint synonymous of enhanced monolithic integrate-ability. Nonetheless, LC-DFBs suffer from the adverse longitudinal spatial hole burning (LSHB) effects materialized by typically quite high threshold current levels. Indeed, the carrier density longitudinal gradient- responsible for modes contending for the available material gain in the cavity- may be alleviated somewhat by segmenting the LC-DFB electrode into two or three reasonably interspaced longitudinal sections. In this work we report on the realization and performance of various electrode partition configurations. At room temperature, the experimental characterization of many as-cleaved LC-DFB devices provides ample evidence of superior performance such as a narrow linewidth (less than 400 kHz), a wide wavelength tune-ability (over 4 nm) and a hop-free single mode emission (side mode suppression ratio (SMSR) exceeding 54dB).

High-frequency dual mode pulsed wave Doppler imaging for monitoring the functional regeneration of adult zebrafish hearts

OpenAIRE

Kang, Bong Jin; Park, Jinhyoung; Kim, Jieun; Kim, Hyung Ham; Lee, Changyang; Hwang, Jae Youn; Lien, Ching-Ling; Shung, K. Kirk

2015-01-01

Adult zebrafish is a well-known small animal model for studying heart regeneration. Although the regeneration of scars made by resecting the ventricular apex has been visualized with histological methods, there is no adequate imaging tool for tracking the functional recovery of the damaged heart. For this reason, high-frequency Doppler echocardiography using dual mode pulsed wave Doppler, which provides both tissue Doppler (TD) and Doppler flow in a same cardiac cycle, is developed with a 30 ...

Dual-mode gradient HPLC procedure for the simultaneous determination of chloroquine and proguanil.

Science.gov (United States)

Paci, A; Caire-Maurisier, A-M; Rieutord, A; Brion, F; Clair, P

2002-01-01

In order to assay the antipaludic capsule of the Service de Santé des Armées (SSA), that contains two antimalarial drugs, i.e. chloroquine sulfate (CQS, cp1) and proguanil hydrochloride (PGH, cp5), a HPLC procedure was developed. A reversed-phase ion-pair high-performance liquid chromatography (HPLC) method with an ultraviolet detection at 254 nm was set up and validated. Elution system includes programming of both organic concentration and flow-rate known as 'dual-mode gradient'. This method allows the simultaneous determination of both active compounds and separation of four process related substances. The method is simple, rapid, selective and accurate, and the precision is good with an inter- and intra-assay of <2%. The sensitivity is particularly suitable for pharmaceutical quality control.

Monitoring and guidance of HIFU beams with dual-mode ultrasound arrays.

Science.gov (United States)

Ballard, John R; Casper, Andrew J; Ebbini, Emad S

2009-01-01

We present experimental results illustrating the unique advantages of dual-mode array (DMUA) systems in monitoring and guidance of high intensity focused ultrasound (HIFU) lesion formation. DMUAs offer a unique paradigm in image-guided surgery; one in which images obtained using the same therapeutic transducer provide feedback for: 1) refocusing the array in the presence of strongly scattering objects, e.g. the ribs, 2) temperature change at the intended location of the HIFU focus, and 3) changes in the echogenicity of the tissue in response to therapeutic HIFU. These forms of feedback have been demonstrated in vitro in preparation for the design and implementation of a real-time system for imaging and therapy with DMUAs. The results clearly demonstrate that DMUA image feedback is spatially accurate and provide sufficient spatial and contrast resolution for identification of high contrast objects like the ribs and significant blood vessels in the path of the HIFU beam.

Fatigue Failure Modes of the Grain Size Transition Zone in a Dual Microstructure Disk

Science.gov (United States)

Gabb, Timothy P.; Kantzos, Pete T.; Palsa, Bonnie; Telesman, Jack; Gayda, John; Sudbrack, Chantal K.

2012-01-01

Mechanical property requirements vary with location in nickel-based superalloy disks. In order to maximize the associated mechanical properties, heat treatment methods have been developed for producing tailored grain microstructures. In this study, fatigue failure modes of a grain size transition zone in a dual microstructure disk were evaluated. A specialized heat treatment method was applied to produce varying grain microstructure in the bore to rim portions of a powder metallurgy processed nickel-based superalloy disk. The transition in grain size was concentrated in a zone of the disk web, between the bore and rim. Specimens were extracted parallel and transversely across this transition zone, and multiple fatigue tests were performed at 427 C and 704 C. Grain size distributions were characterized in the specimens, and related to operative failure initiation modes. Mean fatigue life decreased with increasing maximum grain size, going out through the transition zone. The scatter in limited tests of replicates was comparable for failures of uniform gage specimens in all transition zone locations examined.

A single-longitudinal-mode Brillouin fiber laser passively stabilized at the pump resonance frequency with a dynamic population inversion grating

International Nuclear Information System (INIS)

Spirin, V V; López-Mercado, C A; Kinet, D; Mégret, P; Fotiadi, A A; Zolotovskiy, I O

2013-01-01

We demonstrate a single-longitudinal-mode Brillouin ring fiber laser passively stabilized at the resonance frequency with a 1.7 m section that is an unpumped polarization-maintaining erbium-doped fiber. The two coupled all-fiber Fabry–Perot interferometers that comprise the cavity, in combination with the dynamical population inversion gratings self-induced in the active fiber, provide adaptive pump-mode selection and Stokes wave generation at the same time. The laser is shown to emit a single-frequency Stokes wave with a linewidth narrower than 100 Hz. (letter)

Observation of stable bound soliton with dual-wavelength in a passively mode-locked Er-doped fiber laser

International Nuclear Information System (INIS)

Zheng Yu; Tian Jin-Rong; Dong Zi-Kai; Xu Run-Qin; Li Ke-Xuan; Song Yan-Rong

2017-01-01

A phase-locked bound state soliton with dual-wavelength is observed experimentally in a passively mode-locked Er-doped fiber (EDF) laser with a fiber loop mirror (FLM). The pulse duration of the soliton is 15 ps and the peak-to-peak separation is 125 ps. The repetition rate of the pulse sequence is 3.47 MHz. The output power is 11.8 mW at the pump power of 128 mW, corresponding to the pulse energy of 1.52 nJ. The FLM with a polarization controller can produce a comb spectrum, which acts as a filter. By adjusting the polarization controller or varying the pump power, the central wavelength of the comb spectrum can be tuned. When it combines with the reflective spectrum of the fiber Bragg grating, the total spectrum of the cavity can be cleaved into two parts, then the bound state soliton with dual-wavelength at 1549.7 nm and 1550.4 nm is obtained. (paper)

The dual impact of gender and the influence of timing of parenthood on men’s and women’s career development: Longitudinal findings

OpenAIRE

Abele, Andrea E.; Spurk, Daniel

2012-01-01

This study investigated the impact of gender, the gender-related self-concept (agency and communion), and the timing of parenthood on objective career success of 1,015 highly educated professionals. Hypotheses derived from a dual-impact model of gender and career-related processes were tested in a 5-wave longitudinal study over a time span of 10 years starting with participants’ career entry. In line with our hypotheses we found that the communal component of the gender self-concept had an im...

Covalent Organic Framework Functionalized with 8-Hydroxyquinoline as a Dual-Mode Fluorescent and Colorimetric pH Sensor.

Science.gov (United States)

Chen, Long; He, Linwei; Ma, Fuyin; Liu, Wei; Wang, Yaxing; Silver, Mark A; Chen, Lanhua; Zhu, Lin; Gui, Daxiang; Diwu, Juan; Chai, Zhifang; Wang, Shuao

2018-05-09

Real-time and accurate detection of pH in aqueous solution is of great significance in chemical, environmental, and engineering-related fields. We report here the use of 8-hydroxyquinoline-functionalized covalent organic framework (COF-HQ) for dual-mode pH sensing. In the fluorescent mode, the emission intensity of COF-HQ weakened as the pH decreased, and also displayed a good linear relationship against pH in the range from 1 to 5. In addition, COF-HQ showed discernible color changes from yellow to black as the acidity increased and can be therefore used as a colorimetric pH sensor. All these changes are reversible and COF-HQ can be recycled for multiple detection runs owing to its high hydrolytical stability. It can be further assembled into a mixed matrix membrane for practical applications.

Longitudinal tune control in synchrotrons

International Nuclear Information System (INIS)

Colton, E.P.

1984-01-01

Dual rf systems that use fundamental and higher-harmonic cavities can be used to control the longitudinal tune in synchrotrons. The equations of motion and the Hamiltonian are defined for particle motion using dual rf systems. An example is considered using a second-harmonic system - it is shown, that as phi/sub s/ is increased, a substantial gain in bucket area over a single rf system can be realized by proper relative phasing of the first- and second-harmonic voltages

10 KWe dual-mode space nuclear power system for military and scientific applications

International Nuclear Information System (INIS)

Malloy, J.; Westerman, K.; Rochow, R.; Scoles, S.

1992-01-01

This paper discusses a 10 KWe dual-mode space power system concept which has been identified and is based on INEL's Small Externally-fueled Heat Pipe Thermionic Reactor (SEHPTR) concept. This power system will enhance user capabilities by providing reliable electric power and by providing two propulsion systems; electric power for an arc-jet electric propulsion system and direct thrust by heating hydrogen propellant inside the reactor. The low thrust electric thrusters allow efficient station keeping and long-term maneuvering. This paper will focus on the nuclear power system design, including: the reactor with its UO 2 fuel in tungsten clad, 36 thermionic heat pipe modules (THPMs) which produce electricity within the reactor and remove waste heat, radiation shielding, waste heat radiators, and reactivity control systems. The use of non-vented fuel elements for short lifetime missions (under five years) will be described

Structural Design of Dual-Mode Ramjets and Associated System Issues (Conception structurale des statoreacteurs mixtes et defis systeme associes)

Science.gov (United States)

2010-09-01

Institute PAO Protection Against Oxidation RBCC Rocket Based Combined Cycle RSL Reusable Space Launchers SSTO Single Stage to Orbit TOW Take-Off Weight...Orbit) or Single Stage To Orbit ( SSTO ) vehicles, or other kind of hypersonic vehicles. For example, in the scope of the French PREPHA program, the...study of a generic SSTO vehicle led to conclusion that the best type of airbreathing engine could be the dual-mode ramjet (subsonic then supersonic

Dual-mode T_1 and T_2 magnetic resonance imaging contrast agent based on ultrasmall mixed gadolinium-dysprosium oxide nanoparticles: synthesis, characterization, and in vivo application

International Nuclear Information System (INIS)

Tegafaw, Tirusew; Xu, Wenlong; Ahmad, Md Wasi; Lee, Gang Ho; Baeck, Jong Su; Chang, Yongmin; Bae, Ji Eun; Chae, Kwon Seok; Kim, Tae Jeong

2015-01-01

A new type of dual-mode T_1 and T_2 magnetic resonance imaging (MRI) contrast agent based on mixed lanthanide oxide nanoparticles was synthesized. Gd"3"+ ("8S_7_/_2) plays an important role in T_1 MRI contrast agents because of its large electron spin magnetic moment resulting from its seven unpaired 4f-electrons, and Dy"3"+ ("6H_1_5_/_2) has the potential to be used in T_2 MRI contrast agents because of its very large total electron magnetic moment: among lanthanide oxide nanoparticles, Dy_2O_3 nanoparticles have the largest magnetic moments at room temperature. Using these properties of Gd"3"+ and Dy"3"+ and their oxide nanoparticles, ultrasmall mixed gadolinium-dysprosium oxide (GDO) nanoparticles were synthesized and their potential to act as a dual-mode T_1 and T_2 MRI contrast agent was investigated in vitro and in vivo. The D-glucuronic acid coated GDO nanoparticles (d_a_v_g = 1.0 nm) showed large r_1 and r_2 values (r_2/r_1 ≈ 6.6) and as a result clear dose-dependent contrast enhancements in R_1 and R_2 map images. Finally, the dual-mode imaging capability of the nanoparticles was confirmed by obtaining in vivo T_1 and T_2 MR images. (paper)

Microgeneration of electricity with producer gas in dual fuel mode operation Microgeração de eletricidade com gás de gaseificação num motor gerador dual

Directory of Open Access Journals (Sweden)

Marcelo J. Silva

2011-10-01

Full Text Available Among the alternatives to meet the increasing of world demand for energy, the use of biomass as energy source is one of the most promising as it contributes to reducing emissions of carbon dioxide in the atmosphere. Gasification is a technological process of biomass energy production of a gaseous biofuel. The fuel gas has a low calorific value that can be used in Diesel engine in dual mode for power generation in isolated communities. This study aimed to evaluate the reduction in the consumption of oil Diesel an engine generator, using gas from gasification of wood. The engine generator brand used was a BRANCO, with direct injection power of 7.36 kW (10 HP coupled to an electric generator 5.5 kW. Diesel oil mixed with intake air was injected, as the oil was injected via an injector of the engine (dual mode. The fuel gas was produced in a downdraft gasifier. The engine generator was put on load system from 0.5 kW to 3.5 kW through a set of electrical resistances. Diesel oil consumption was measured with a precision scale. It was concluded that the engine converted to dual mode when using the gas for the gasification of wood decreased Diesel consumption by up to 57%.Dentre as alternativas à crescente demanda energética mundial, o uso da biomassa como fonte de energia é uma das formas mais promissoras, pois contribui para a redução das emissões de dióxido de carbono na atmosfera. A gaseificação é uma tecnologia de transformação energética da biomassa num biocombustível gasoso. O gás de gaseificação é um combustível de baixo poder calorífico que pode ser utilizado em motor ciclo Diesel no modo dual para geração de energia elétrica em comunidades isoladas. Este trabalho teve por objetivo avaliar a redução no consumo de Diesel num motor gerador, com a utilização de gás da gaseificação da madeira. O motor avaliado foi da marca BRANCO, com injeção direta e potência de 7,36 kW (10 cv acoplado a um gerador elétrico de 5

Stable and High OSNR Compound Linear-Cavity Single-Longitudinal-Mode Erbium-Doped Silica Fiber Laser Based on an Asymmetric Four-Cavity Structure

International Nuclear Information System (INIS)

Feng Ting; Yan Feng-Ping; Li Qi; Peng Wan-Jing; Feng Su-Chun; Wen Xiao-Dong; Tan Si-Yu; Liu Peng

2012-01-01

We propose a stable and high optical signal-to-noise ratio (OSNR) compound linear-cavity single-longitudinal-mode (SLM) erbium-doped silica fiber laser. It consists of three uniform fiber Bragg gratings (FBGs) and two fiber couplers to form a simple asymmetric four-cavity structure to select the longitudinal mode. The stable SLM operation at the wavelength of 1544.053 nm with a 3 dB bandwidth of 0.014 nm and an OSNR of ∼60 dB was verified experimentally. Under laboratory conditions, a power fluctuation performance of less than 0.05 dB for 5 h and wavelength variation of less than 0.01 nm for about 150 min is demonstrated. Finally, the characteristic of laser output power as a function of pump power is investigated. The proposed system provides a simple and cost-effective approach to realize a stable SLM fiber laser

An assessment of the dual-mode reactivity controlled compression ignition/conventional diesel combustion capabilities in a EURO VI medium-duty diesel engine fueled with an intermediate ethanol-gasoline blend and biodiesel

International Nuclear Information System (INIS)

Benajes, Jesús; García, Antonio; Monsalve-Serrano, Javier; Balloul, Iyad; Pradel, Gérard

2016-01-01

Highlights: • Reactivity controlled compression ignition regime utilized from 25% to 35% load. • Dual-mode reduces the regeneration periods of the diesel particulate filter. • The use of near-term available biofuels allows good performance and emissions. • Dual-mode leads to 2% greater efficiency than diesel combustion at high engine speeds. - Abstract: This work investigates the capabilities of the dual-mode reactivity controlled compression ignition/conventional diesel combustion engine operation to cover the full operating range of a EURO VI medium-duty diesel engine with compression ratio of 17.5:1. This concept is based on covering all the engine map switching between the reactivity controlled compression ignition and the conventional diesel combustion operating modes. Specifically, the benefits of reactivity controlled compression ignition combustion are exploited whenever possible according to certain restrictions, while the conventional diesel combustion operation is used to cover the zones of the engine map in which the reactivity controlled compression ignition operation is limited. The experiments were conducted using a single-cylinder research diesel engine derived from the multi-cylinder production engine. In addition, considering the mandatory presence of biofuels in the future context of road transport and the ability of ethanol to be blended with gasoline, the low reactivity fuel used in the study is a blend of 20% ethanol by volume with 80% of 95 octane number gasoline. Moreover, a diesel containing 7% of biodiesel has been used as high reactivity fuel. Firstly, a reactivity controlled compression ignition mapping is performed to check the operational limits of the concept in this engine platform. Later, based on the results, the potential of the dual-mode concept is discussed. Results suggest that, under the constraints imposed, reactivity controlled compression ignition combustion can be utilized between 25% and 35% load. In this region

Novel control modes to improve the performance of rectilinear ion trap mass spectrometer with dual pressure chambers

Science.gov (United States)

Huo, Xinming; Tang, Fei; Zhang, Xiaohua; Chen, Jin; Zhang, Yan; Guo, Cheng'an; Wang, Xiaohao

2016-10-01

The rectilinear ion trap (RIT) has gradually become one of the preferred mass analyzers for portable mass spectrometers because of its simple configuration. In order to enhance the performance, including sensitivity, quantitation capability, throughput, and resolution, a novel RIT mass spectrometer with dual pressure chambers was designed and characterized. The studied system constituted a quadrupole linear ion trap (QLIT) in the first chamber and a RIT in the second chamber. Two control modes are hereby proposed: Storage Quadrupole Linear Ion Trap-Rectilinear Ion Trap (SQLIT-RIT) mode, in which the QLIT was used at high pressure for ion storage and isolation, and the RIT was used for analysis; and Analysis Quadrupole Linear Ion Trap-Rectilinear Ion Trap (AQLIT-RIT) mode, in which the QLIT was used for ion storage and cooling. Subsequently, synchronous scanning and analysis were carried out by QLIT and RIT. In SQLIT-RIT mode, signal intensity was improved by a factor of 30; the limit of quantitation was reduced more than tenfold to 50 ng mL-1, and an optimal duty cycle of 96.4% was achieved. In AQLIT-RIT mode, the number of ions coexisting in the RIT was reduced, which weakened the space-charge effect and reduced the mass shift. Furthermore, the mass resolution was enhanced by a factor of 3. The results indicate that the novel control modes achieve satisfactory performance without adding any system complexity, which provides a viable pathway to guarantee good analytical performance in miniaturization of the mass spectrometer.

Dual-Mode Scramjet Flameholding Operability Measurements

Science.gov (United States)

Donohue, James M.

2012-01-01

Flameholding measurements were made in two different direct connect combustor facilities that were designed to simulate a cavity flameholder in the flowfield of a hydrocarbon fueled dual-mode scramjet combustor. The presence of a shocktrain upstream of the flameholder has a significant impact on the inlet flow to the combustor and on the flameholding limits. A throttle was installed in the downstream end of the test rigs to provide the needed back-pressurization and decouple the operation of the flameholder from the backpressure formed by heat release and thermal choking, as in a flight engine. Measurements were made primarily with ethylene fuel but a limited number of tests were also performed with heated gaseous JP-7 fuel injection. The flameholding limits were measured by ramping inlet air temperature down until blowout was observed. The tests performed in the United Technologies Research Center (UTRC) facility used a hydrogen fueled vitiated air heater, Mach 2.2 and 3.3 inlet nozzles, a scramjet combustor rig with a 1.666 by 6 inch inlet and a 0.65 inch deep cavity. Mean blowout temperature measured at the baseline condition with ethylene fuel, the Mach 2.2 inlet and a cavity pressure of 21 psia was 1502 oR. Flameholding sensitivity to a variety of parameters was assessed. Blowout temperature was found to be most sensitive to fuel injection location and fuel flowrates and surprisingly insensitive to operating pressure (by varying both back-pressurization and inlet flowrate) and inlet Mach number. Video imaging through both the bottom and side wall windows was collected simultaneously and showed that the flame structure was quite unsteady with significant lateral movements as well as movement upstream of the flameholder. Experiments in the University of Virginia (UVa) test facility used a Mach 2 inlet nozzle with a 1 inch by 1.5 inch exit cross section, an aspect ratio of 1.5 versus 3.6 in the UTRC facility. The UVa facility tests were designed to measure the

Self-starting and overclocking a harmonically mode-locking WRC-FPLD with a dual-loop feedback controller for 10 Gb s−1 pulse-data transmission

International Nuclear Information System (INIS)

Lin, Chun-Ju; Chi, Yu-Chieh; Lin, Gong-Ru

2013-01-01

The self-starting and overclocking of a harmonically mode-locked weak-resonant-cavity Fabry–Perot laser diode (WRC-FPLD) with a dual-loop coupled optoelectronic oscillator (COEO) based feedback controller is demonstrated to perform a clock-free pulsed data transmission at 10 Gb s −1 . The WRC-FPLD is considered as the preferred candidate for harmonic mode-locking due to its highly asymmetric cavity architecture, whereby the spontaneous noise can be significantly suppressed without inducing large intra-cavity loss. With the dual-loop COEO configuration, the WRC-FPLD can be boosted to four times of its original modulation bandwidth such that the pulsed carrier quality can be refined. The structure-optimizing principle with the closed-loop model is corroborated by the effective spurious-noise-suppression. The lowest phase noises as low as −100 dBc Hz −1 at 10 kHz with corresponding RMS timing jitter of 0.67 ps are measured. This is achieved by individually inserting 100 and 120 m long single mode fiber segments into two decoupled arms, the dual-loop COEO before the optical receiver pair. The BER performance reaches a minimum with the optimized SMF segment lengths. However, the spurious peaks arise to degrade the BER performance as the phase noise and jitter are inevitably enlarged when inserting longer SMF segments. After modulating the optimized output pulse train with the pseudo-random-bit-sequence data triggered by the same COEO clock, the SNR can achieve 10.9 dB and the receiving sensitivity is −19.2 dBm. (letter)

Research on Control Strategies of an Open-End Winding Permanent Magnet Synchronous Driving Motor (OW-PMSM-Equipped Dual Inverter with a Switchable Winding Mode for Electric Vehicles

Directory of Open Access Journals (Sweden)

Liang Chu

2017-05-01

Full Text Available An open-end winding permanent magnet synchronous motor (PMSM has a larger range of speed regulation than normal PMSM with the same DC voltage, and the control method is more flexible. It can also manage energy distribution between two power sources without a DC/DC converter. This paper aims at an electric vehicle equipped with OW-PMSM drive system with dual power sources and dual inverters; based on analyzing the external characteristics of each winding mode, we propose a winding mode switching strategy whose torque saturation judgmental algorithm, which is insensitive to motor’s parameters, could automatically realize upswitching of the winding mode. The proposed multi-level current hysteresis modulation algorithm could set the major power source and switch it at any time in independent mode, which accomplishes energy distribution between two power sources; its two control methods, low switching frequency method and high power difference method, could achieve different energy distribution effects. Simulation results confirm the validity and effectiveness of the winding mode switching strategy and current modulation method. They also show that an electric vehicle under the proposed control methods has better efficiency than one equipped with a traditional OW-PMSM drive system under traditional control.

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.

Development of Real-Time Dual-Display Handheld and Bench-Top Hybrid-Mode SD-OCTs

Directory of Open Access Journals (Sweden)

Nam Hyun Cho

2014-01-01

Full Text Available Development of a dual-display handheld optical coherence tomography (OCT system for retina and optic-nerve-head diagnosis beyond the volunteer motion constraints is reported. The developed system is portable and easily movable, containing the compact portable OCT system that includes the handheld probe and computer. Eye posterior chambers were diagnosed using the handheld probe, and the probe could be fixed to the bench-top cradle depending on the volunteers’ physical condition. The images obtained using this handheld probe were displayed in real time on the computer monitor and on a small secondary built-in monitor; the displayed images were saved using the handheld probe’s built-in button. Large-scale signal-processing procedures such as k-domain linearization, fast Fourier transform (FFT, and log-scaling signal processing can be rapidly applied using graphics-processing-unit (GPU accelerated processing rather than central-processing-unit (CPU processing. The Labview-based system resolution is 1,024 × 512 pixels, and the frame rate is 56 frames/s, useful for real-time display. The 3D images of the posterior chambers including the retina, optic-nerve head, blood vessels, and optic nerve were composed using real-time displayed images with 500 × 500 × 500 pixel resolution. A handheld and bench-top hybrid mode with a dual-display handheld OCT was developed to overcome the drawbacks of the conventional method.

Multipurpose, dual-mode imaging in the 3-5 μm range (MWIR) for artwork diagnostics: A systematic approach

Science.gov (United States)

Daffara, Claudia; Parisotto, Simone; Ambrosini, Dario

2018-05-01

We present a multi-purpose, dual-mode imaging method in the Mid-Wavelength Infrared (MWIR) range (from 3 μm to 5 μm) for a more efficient nondestructive analysis of artworks. Using a setup based on a MWIR thermal camera and multiple radiation sources, two radiometric image datasets are acquired in different acquisition modalities, the image in quasi-reflectance mode (TQR) and the thermal sequence in emission mode. Here, the advantages are: the complementarity of the information; the use of the quasi-reflectance map for calculating the emissivity map; the use of TQR map for a referentiation to the visible of the thermographic images. The concept of the method is presented, the practical feasibility is demonstrated through a custom imaging setup, the potentiality for the nondestructive analysis is shown on a notable application to cultural heritage. The method has been used as experimental tool in support of the restoration of the mural painting "Monocromo" by Leonardo da Vinci. Feedback from the operators and a comparison with some conventional diagnostic techniques is also given to underline the novelty and potentiality of the method.

Adaptive sampling dual terahertz comb spectroscopy using dual free-running femtosecond lasers.

Science.gov (United States)

Yasui, Takeshi; Ichikawa, Ryuji; Hsieh, Yi-Da; Hayashi, Kenta; Cahyadi, Harsono; Hindle, Francis; Sakaguchi, Yoshiyuki; Iwata, Tetsuo; Mizutani, Yasuhiro; Yamamoto, Hirotsugu; Minoshima, Kaoru; Inaba, Hajime

2015-06-02

Terahertz (THz) dual comb spectroscopy (DCS) is a promising method for high-accuracy, high-resolution, broadband THz spectroscopy because the mode-resolved THz comb spectrum includes both broadband THz radiation and narrow-line CW-THz radiation characteristics. In addition, all frequency modes of a THz comb can be phase-locked to a microwave frequency standard, providing excellent traceability. However, the need for stabilization of dual femtosecond lasers has often hindered its wide use. To overcome this limitation, here we have demonstrated adaptive-sampling THz-DCS, allowing the use of free-running femtosecond lasers. To correct the fluctuation of the time and frequency scales caused by the laser timing jitter, an adaptive sampling clock is generated by dual THz-comb-referenced spectrum analysers and is used for a timing clock signal in a data acquisition board. The results not only indicated the successful implementation of THz-DCS with free-running lasers but also showed that this configuration outperforms standard THz-DCS with stabilized lasers due to the slight jitter remained in the stabilized lasers.

New Edge Coherent Mode Providing Continuous Transport in Long Pulse H-mode Plasmas

DEFF Research Database (Denmark)

Wang, H.Q.; Xu, G.S.; Wan, B.N.

2014-01-01

An electrostatic coherent mode near the electron diamagnetic frequency (20–90 kHz) is observed in the steep-gradient pedestal region of long pulse H-mode plasmas in the Experimental Advanced Super-conducting Tokamak, using a newly developed dual gas-puff-imaging system and diamond-coated reciproc...

Longitudinal feedback system for PEP

International Nuclear Information System (INIS)

Allen, M.A.; Cornacchia, M.; Millich, A.

1979-02-01

Whether the wide bandwidth longitudinal feedback system described in this paper is made to act on the individual modes in frequency domain or on the individual bunches in time domain, it represents a clean and efficient way of damping the longitudinal oscillations without influencing other beam parameters such as bunch shape or synchrotron frequency distribution. The frequency domain feedback presents the advantage of providing information on which modes are unstable and on their risetimes, which may be helpful in locating dangerous resonators in the ring

Characteristics of the Single-Longitudinal-Mode Planar-Waveguide External Cavity Diode Laser at 1064 nm

Science.gov (United States)

Numata, Kenji; Alalusi, Mazin; Stolpner, Lew; Margaritis, Georgios; Camp, Jordan; Krainak, Michael

2014-01-01

We describe the characteristics of the planar-waveguide external cavity diode laser (PW-ECL). To the best of our knowledge, it is the first butterfly-packaged 1064 nm semiconductor laser that is stable enough to be locked to an external frequency reference. We evaluated its performance from the viewpoint of precision experiments. Using a hyperfine absorption line of iodine, we suppressed its frequency noise by a factor of up to 104 at 10 mHz. The PWECL's compactness and low cost make it a candidate to replace traditional Nd:YAG nonplanar ring oscillators and fiber lasers in applications that require a single longitudinal mode.

Temporal resolution measurement of 128-slice dual source and 320-row area detector computed tomography scanners in helical acquisition mode using the impulse method.

Science.gov (United States)

Hara, Takanori; Urikura, Atsushi; Ichikawa, Katsuhiro; Hoshino, Takashi; Nishimaru, Eiji; Niwa, Shinji

2016-04-01

To analyse the temporal resolution (TR) of modern computed tomography (CT) scanners using the impulse method, and assess the actual maximum TR at respective helical acquisition modes. To assess the actual TR of helical acquisition modes of a 128-slice dual source CT (DSCT) scanner and a 320-row area detector CT (ADCT) scanner, we assessed the TRs of various acquisition combinations of a pitch factor (P) and gantry rotation time (R). The TR of the helical acquisition modes for the 128-slice DSCT scanner continuously improved with a shorter gantry rotation time and greater pitch factor. However, for the 320-row ADCT scanner, the TR with a pitch factor of pitch factor of >1.0, it was approximately one half of the gantry rotation time. The maximum TR values of single- and dual-source helical acquisition modes for the 128-slice DSCT scanner were 0.138 (R/P=0.285/1.5) and 0.074s (R/P=0.285/3.2), and the maximum TR values of the 64×0.5- and 160×0.5-mm detector configurations of the helical acquisition modes for the 320-row ADCT scanner were 0.120 (R/P=0.275/1.375) and 0.195s (R/P=0.3/0.6), respectively. Because the TR of a CT scanner is not accurately depicted in the specifications of the individual scanner, appropriate acquisition conditions should be determined based on the actual TR measurement. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Dual Mode Fluorophore-Doped Nickel Nitrilotriacetic Acid-Modified Silica Nanoparticles Combine Histidine-Tagged Protein Purification with Site-Specific Fluorophore Labeling

OpenAIRE

Kim, Sung Hoon; Jeyakumar, M.; Katzenellenbogen, John A.

2007-01-01

We present the first example of a fluorophore-doped nickel chelate surface- modified silica nanoparticle that functions in a dual mode, combining histidine-tagged protein purification with site-specific fluorophore labeling. Tetramethylrhodamine (TMR)-doped silica nanoparticles, estimated to contain 700–900 TMRs per ca. 23-nm particle, were surface modified with nitrilotriacetic acid (NTA), producing TMR-SiO2-NTA-Ni+2. Silica-embedded TMR retains very high quantum yield, is resistant to quenc...

Simulation de Ia propagation de fissures dans les solides elastiques en modes mixtes par Ia methode des equations integrales duales

OpenAIRE

Kebir , Hocine; Roelandt , Jean Marc; Gaudin , Jocelyn

2000-01-01

International audience; The present paper is concerned with the effective numerical implementation of the two dimensional Dual Boundary element method to analyse the mixed-mode crack growth All the boundaries are discretized with discontinuous quadratic boundary elements and the crack-tip is modeled by singular elements that exactly represent the strain field singularity $1/\\sqrt{r}$. The Stress lntensity Factors can be computed very accurately from the crack opening dis placement at collocat...

Electron heating mode transition induced by mixing radio frequency and ultrahigh frequency dual frequency powers in capacitive discharges

International Nuclear Information System (INIS)

Sahu, B. B.; Han, Jeon G.

2016-01-01

Electron heating mode transitions induced by mixing the low- and high-frequency power in dual-frequency nitrogen discharges at 400 mTorr pressure are presented. As the low-frequency (13.56 MHz) power decreases and high-frequency (320 MHz) power increases for the fixed power of 200 W, there is a transition of electron energy distribution function (EEDF) from Druyvesteyn to bi-Maxwellian type characterized by a distinguished warm electron population. It is shown that this EEDF evolution is attributed to the transition from collisional to collisionless stochastic heating of the low-energy electrons.

Internet and telephonic IVR mixed-mode survey for longitudinal studies: choice, retention, and data equivalency.

Science.gov (United States)

Verma, Santosh K; Courtney, Theodore K; Lombardi, David A; Chang, Wen-Ruey; Huang, Yueng-Hsiang; Brennan, Melanye J; Perry, Melissa J

2014-01-01

This study examined data equivalency and loss to follow-up rates from Internet and interactive voice response (IVR) system surveys in a prospective-cohort study. 475 limited-service restaurant workers participating in the 12-week study were given a choice to report their weekly slipping experience by either IVR or Internet. Demographic differences, loss to follow-up, self-reported rates of slipping, and selection of first and last choices were compared. Loss to follow-up rates were slightly higher for those choosing the IVR mode. Rates of slipping and selection of first and last choices were not significantly different between survey modes. Propensity to choose an Internet survey decreased with increasing age, and was the lowest among Spanish speakers (5%) and those with less than a high school education (14%). Studies relying solely on Internet-based data collection may lead to selective exclusion of certain populations. Findings suggest that Internet and IVR may be combined as survey modalities within longitudinal studies. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Experimental Investigation Of Biogas-Biodiesel Dual Fuel Combustion In A Diesel Engine

Directory of Open Access Journals (Sweden)

Ramesha D. K.

2015-06-01

Full Text Available This study is an attempt at achieving diesel fuel equivalent performance from diesel engines with maximum substitution of diesel with renewable fuels. In this context the study has been designed to analyze the influence of B20 algae biodiesel as a pilot fuel in a biodiesel biogas dual fuel engine, and results are compared to those of biodiesel and diesel operation at identical engine settings. Experiments were performed at various loads from 0 to 100 % of maximum load at a constant speed of 1500 rpm. In general, B20 algae biodiesel is compatible with diesel in terms of performance and combustion characteristics. Dual fuel mode operation displays lower thermal efficiency and higher fuel consumption than for other fuel modes of the test run across the range of engine loads. Dual fuel mode displayed lower emissions of NOx and Smoke opacity while HC and CO concentrations were considerably higher as compared to other fuels. In dual fuel mode peak pressure and heat release rate were slightly higher compared to diesel and biodiesel mode of operation for all engine loads.

Reproducibility of trabecular bone score with different scan modes using dual-energy X-ray absorptiometry: a phantom study

Energy Technology Data Exchange (ETDEWEB)

Bandirali, Michele; Messina, Carmelo [Universita degli Studi di Milano, Scuola di Specializzazione in Radiodiagnostica, Milano (Italy); Di Leo, Giovanni [Unita di Radiologia, IRCCS Policlinico San Donato, San Donato Milanese (Italy); Pastor Lopez, Maria Juana; Ulivieri, Fabio M. [Servizio di Medicina Nucleare, Ospedale Maggiore, Mineralometria Ossea Computerizzata e Ambulatorio Malattie Metabolismo Minerale e Osseo, Milano (Italy); Mai, Alessandro [Universita degli Studi di Milano, Tecniche di Radiologia Medica, per Immagini e Radioterapia, Milano (Italy); Sardanelli, Francesco [Unita di Radiologia, IRCCS Policlinico San Donato, San Donato Milanese (Italy); Universita degli Studi di Milano, Dipartimento di Scienze Biomediche per la Salute, San Donato Milanese (Italy)

2014-08-12

The trabecular bone score (TBS) accounts for the bone microarchitecture and is calculated on dual-energy X-ray absorptiometry (DXA). We estimated the reproducibility of the TBS using different scan modes compared to the reproducibility bone mineral density (BMD). A spine phantom was used with a Hologic QDR-Discovery A densitometer. For each scan mode [fast array, array, high definition (HD)], 25 scans were automatically performed without phantom repositioning; a further 25 scans were performed with phantom repositioning. For each scan, the TBS was obtained. The coefficient of variation (CoV) was calculated as the ratio between standard deviation and mean; percent least significant change (LSC%) as 2.8 x CoV; reproducibility as the complement to 100 % of LSC%. Differences among scan modes were assessed using ANOVA. Without phantom repositioning, the mean TBS (mm{sup -1}) was: 1.352 (fast array), 1.321 (array), and 1.360 (HD); with phantom repositioning, it was 1.345, 1.332, and 1.362, respectively. Reproducibility of the TBS without phantom repositioning was 97.7 % (fast array), 98.3 % (array), and 98.2 % (HD); with phantom repositioning, it was 97.9 %, 98.7 %, and 98.4 %, respectively. LSC% was ≤2.26 %. Differences among scan modes were all statistically significant (p ≤ 0.019). Reproducibility of BMD was 99.1 % with all scan modes, while LSC% was from 0.86 % to 0.91 %. Reproducibility error of the TBS was 2-3-fold higher than that of BMD. Although statistically significant, differences in TBS among scan modes were within the highest LSC%. Thus, the three scan modes can be considered interchangeable. (orig.)

Recent Advances in Cancer Therapy Based on Dual Mode Gold Nanoparticles

Directory of Open Access Journals (Sweden)

Ellas Spyratou

2017-12-01

Full Text Available Many tumor-targeted strategies have been used worldwide to limit the side effects and improve the effectiveness of therapies, such as chemotherapy, radiotherapy (RT, etc. Biophotonic therapy modalities comprise very promising alternative techniques for cancer treatment with minimal invasiveness and side-effects. These modalities use light e.g., laser irradiation in an extracorporeal or intravenous mode to activate photosensitizer agents with selectivity in the target tissue. Photothermal therapy (PTT is a minimally invasive technique for cancer treatment which uses laser-activated photoabsorbers to convert photon energy into heat sufficient to induce cells destruction via apoptosis, necroptosis and/or necrosis. During the last decade, PTT has attracted an increased interest since the therapy can be combined with customized functionalized nanoparticles (NPs. Recent advances in nanotechnology have given rise to generation of various types of NPs, like gold NPs (AuNPs, designed to act both as radiosensitizers and photothermal sensitizing agents due to their unique optical and electrical properties i.e., functioning in dual mode. Functionalized AuNPS can be employed in combination with non-ionizing and ionizing radiation to significantly improve the efficacy of cancer treatment while at the same time sparing normal tissues. Here, we first provide an overview of the use of NPs for cancer therapy. Then we review many recent advances on the use of gold NPs in PTT, RT and PTT/RT based on different types of AuNPs, irradiation conditions and protocols. We refer to the interaction mechanisms of AuNPs with cancer cells via the effects of non-ionizing and ionizing radiations and we provide recent existing experimental data as a baseline for the design of optimized protocols in PTT, RT and PTT/RT combined treatment.

Nonlinear longitudinal dynamics studies at the ALS

International Nuclear Information System (INIS)

Byrd, J.M.; Cheng, W.-H.; De Santis, S.; Li, D.; Stupakov, G.; Zimmermann, F.

1999-01-01

We present a summary of results for a variety of studies of nonlinear longitudinal dynamics in the Advanced Light Source, an electron storage ring. These include observation of decoherence at injection, decay of an injected beam, forced synchrotron oscillations and diffusion from one bunch to the next. All of the measurements were made using a dual-scan streak camera which allowed the real-time observation of the longitudinal distribution of the electron beam

Comparison of prospective electrocardiography-gating high-pitch mode and without electrocardiography-synchronization high-pitch mode acquisition for the image quality and radiation doses of the aortic using dual-source CT

International Nuclear Information System (INIS)

Li Jian; Huan Yi; Zhao Hongliang; Wang Ying; Liu Ying; Wei Mengqi; Shi Mingguo; Zheng Minwen

2013-01-01

Objective: To evaluate the application of prospective ECG-gating Flash spiral scan mode dual-source CT in aortography, and compare it's image quality and radiation dose with without ECG-synchronization high-pitch spiral scanning mode. Methods: Fifty consecutive patients (Group A) with suspected aortic dissection or after operations for the aortic dissection were scanned with prospective ECG-gated high-pitch scan and another 50 consecutive patients (Group B) were analyzed by non-ECG-gated high-pitch scan. Image quality of the aortic was assessed by two independent readers. Image noise was measured, radiation dose estimates were calculated. The imaging quality of the aortic and the radiation dose were compared with Mann-whitney U and t test. Results: The average image quality score [(1.18 ± 0.40) in group A and (1.23 ± 0.31) in group B] showed no significant difference between group A and group B (U = 1.20, P = 0.23). The mean radiation dose of group A was lower than that of group B [(1.49 ± 0.38) mSv in group A, (2.79 ± 0.54) mSv in group B, t = 13.677, P < 0.05]. Conclusion: Prospective ECG-gated dual source CT Flash spiral scanning with low radiation dose and good image quality in the aortic dissection with high value of clinical application. (authors)

A comparative study on dual colour soft aperture cascaded second ...

Indian Academy of Sciences (India)

2014-02-09

Feb 9, 2014 ... second-order mode-locking with different nonlinear optical crystals ... delivers stable dual wavelength cw mode-locked pulse train with pulse ... Mode-locking; ultrafast processes; optical susceptibility; frequency conversion;.

Prospectively Electrocardiogram-Gated High-Pitch Spiral Acquisition Mode Dual-Source CT Coronary Angiography in Patients with High Heart Rates: Comparison with Retrospective Electrocardiogram-Gated Spiral Acquisition Mode

Energy Technology Data Exchange (ETDEWEB)

Sun, Kai; Ma, Rui; Wang, Li Jun [Dept. of Radiology, Baotou Central Hospital, Baotou (China); Li, Li Gang; Chen, Jiu Hong [CT BM Clinic Marketing, Siemens Healthcare, Beijing (China)

2012-11-15

To assess the image quality and effective radiation dose of prospectively electrocardiogram (ECG)-gated high-pitch spiral acquisition mode (flash mode) of dual-source CT (DSCT) coronary angiography (CTCA) in patients with high heart rates (HRs) as compared with retrospectively ECG-gated spiral acquisition mode. Two hundred and sixty-eight consecutive patients (132 female, mean age: 55 {+-} 11 years) with mean HR > 65 beats per minute (bpm) were prospectively included in this study. The patients were divided into two groups. Collection was performed in group A CTCA using flash mode setting at 20-30% of the R-R interval, and retrospectively ECG-gated spiral acquisition mode in group B. The image noise, contrast-to-noise ratio (CNR), image quality scores, effective radiation dose and influencing factors on image quality between the two groups were assessed. There were no significant differences in image quality scores and proportions of non-diagnostic coronary artery segments between two groups (image quality scores: 1.064 {+-} 0.306 [group A] vs. 1.084 {+-} 0.327 [group B], p = 0.063; proportion of non-diagnostic coronary artery segments: segment-based analysis 1.52% (group A) vs. 1.74% (group B), p = 0.345; patient-based analysis 7.5% (group A) vs. 6.7% (group B), p = 0.812). The estimated radiation dose was 1.0 {+-} 0.16 mSv in group A and 7.1 {+-} 1.05 mSv in group B (p = 0.001). In conclusion, in patients with HRs > 65 bpm without cardiac arrhythmia, the prospectively high-pitch spiral-acquisition mode with image-acquired timing set at 20-30% of the R-R interval provides a similar image quality and low rate of non-diagnostic coronary segments to the retrospectively ECG-gated low-pitch spiral acquisition mode, with significant reduction of radiation exposure.

Prospectively Electrocardiogram-Gated High-Pitch Spiral Acquisition Mode Dual-Source CT Coronary Angiography in Patients with High Heart Rates: Comparison with Retrospective Electrocardiogram-Gated Spiral Acquisition Mode

International Nuclear Information System (INIS)

Sun, Kai; Ma, Rui; Wang, Li Jun; Li, Li Gang; Chen, Jiu Hong

2012-01-01

To assess the image quality and effective radiation dose of prospectively electrocardiogram (ECG)-gated high-pitch spiral acquisition mode (flash mode) of dual-source CT (DSCT) coronary angiography (CTCA) in patients with high heart rates (HRs) as compared with retrospectively ECG-gated spiral acquisition mode. Two hundred and sixty-eight consecutive patients (132 female, mean age: 55 ± 11 years) with mean HR > 65 beats per minute (bpm) were prospectively included in this study. The patients were divided into two groups. Collection was performed in group A CTCA using flash mode setting at 20-30% of the R-R interval, and retrospectively ECG-gated spiral acquisition mode in group B. The image noise, contrast-to-noise ratio (CNR), image quality scores, effective radiation dose and influencing factors on image quality between the two groups were assessed. There were no significant differences in image quality scores and proportions of non-diagnostic coronary artery segments between two groups (image quality scores: 1.064 ± 0.306 [group A] vs. 1.084 ± 0.327 [group B], p = 0.063; proportion of non-diagnostic coronary artery segments: segment-based analysis 1.52% (group A) vs. 1.74% (group B), p = 0.345; patient-based analysis 7.5% (group A) vs. 6.7% (group B), p = 0.812). The estimated radiation dose was 1.0 ± 0.16 mSv in group A and 7.1 ± 1.05 mSv in group B (p = 0.001). In conclusion, in patients with HRs > 65 bpm without cardiac arrhythmia, the prospectively high-pitch spiral-acquisition mode with image-acquired timing set at 20-30% of the R-R interval provides a similar image quality and low rate of non-diagnostic coronary segments to the retrospectively ECG-gated low-pitch spiral acquisition mode, with significant reduction of radiation exposure.

A dual-mode nanosensor based on carbon quantum dots and gold nanoparticles for discriminative detection of glutathione in human plasma.

Science.gov (United States)

Shi, Yupeng; Pan, Yi; Zhang, Heng; Zhang, Zhaomin; Li, Mei-Jin; Yi, Changqing; Yang, Mengsu

2014-06-15

Glutathione (GSH) plays key roles in biological systems and serves many cellular functions. Since biothiols all incorporate thiol, carboxylic and amino groups, discriminative detection of GSH over cysteine (Cys) and homocysteine (Hcy) is still challenging. We herein report a dual-mode nanosensor with both colorimetric and fluorometric readout based on carbon quantum dots and gold nanoparticles for discriminative detection of GSH over Cys/Hcy. The proposed sensing system consists of AuNPs and fluorescent carbon quantum dots (CQDs), where CQDs function as fluorometric reporter, and AuNPs serve a dual function as colorimetric reporter and fluorescence quencher. The mechanism of the nanosensor is based on two distance-dependent phenomenons, color change of AuNPs and FRET. Through controlling the surface properties of as-prepared nanoparticles, the addition of CQDs into AuNPs colloid solution might induce the aggregation of AuNPs and CQDs, leading to AuNPs color changing from red to blue and CQDs fluorescence quench. However, the presence of GSH can protect AuNPs from being aggregated and enlarge the inter-particle distance, which subsequently produces color change and fluorescent signal recovery. The nanosensor described in this report reflects on its simplicity and flexibility, where no further surface functionalization is required for the as-prepared nanoparticles, leading to less laborious and more cost-effective synthesis. The proposed dual-mode nanosensor demonstrated highly selectivity toward GSH, and allows the detection of GSH as low as 50 nM. More importantly, the nanosensor could not only function in aqueous solution for GSH detection with high sensitivity but also exhibit sensitive responses toward GSH in complicated biological environments, demonstrating its potential in bioanalysis and biodection, which might be significant in disease diagnosis in the future. Copyright © 2014 Elsevier B.V. All rights reserved.

Differential associations between dual-task walking abilities and usual gait patterns in healthy older adults-Results from the Baltimore Longitudinal Study of Aging.

Science.gov (United States)

Ko, Seung-Uk; Jerome, Gerald J; Simonsick, Eleanor M; Studenski, Stephanie; Hausdorff, Jeffrey M; Ferrucci, Luigi

2018-04-27

It is well established that facing a cognitive challenge while carrying out a motor task interferes with the motor task performance, and in general the ability of handling a dual-task declines progressively with aging. However, the reasons for this decline have not been fully elucidated. Understanding the association between usual-walking gait patterns and dual-task walking performance may provide new insights into the mechanisms that lead to gait deterioration in normal aging and its link to motor and cognitive function. Our aim was to assess usual gait parameters in kinematics and kinetics to understand how these parameters are related with a specific task in dual-task walking. We hypothesized that difficulty in dual-task walking would be associated with gait deteriorations as reflected in range of motion and mechanical work expenditure. We tested this hypothesis by quantifying the gait of 383 participants in the Baltimore Longitudinal Study of Aging (68% of whom successfully completed the dual-task walk, 21% failed the motor task, and 11% failed the cognitive task). Compared to successful performers, participants who failed the single motor task had slower gait speed, shorter stride length, higher cadence, and lower range of motion in the knee and ankle joints (p task while walking had longer double support time (p = 0.003), and greater knee absorptive mechanical work (p = 0. 001) and lower ankle generative mechanical work (p task walking may be useful for monitoring subtle and diverse gait deteriorations in aging and possibly for designing interventions for maintaining and regaining proper gait patterns in older adults. Copyright © 2018 Elsevier B.V. All rights reserved.

A longitudinal investigation of older adults' physical activity: Testing an integrated dual-process model.

Science.gov (United States)

Arnautovska, Urska; Fleig, Lena; O'Callaghan, Frances; Hamilton, Kyra

2017-02-01

To assess the effects of conscious and non-conscious processes for prediction of older adults' physical activity (PA), we tested a dual-process model that integrated motivational (behavioural intention) and volitional (action planning and coping planning) processes with non-conscious, automatic processes (habit). Participants (N = 215) comprised community-dwelling older adults (M = 73.8 years). A longitudinal design was adopted to investigate direct and indirect effects of intentions, habit strength (Time 1), and action planning and coping planning (Time 2) on PA behaviour (Time 3). Structural equation modelling was used to evaluate the model. The model provided a good fit to the data, accounting for 44% of the variance in PA behaviour at Time 3. PA was predicted by intentions, action planning, and habit strength, with action planning mediating the intention-behaviour relationship. An effect of sex was also found where males used fewer planning strategies and engaged in more PA than females. By investigating an integration of conscious and non-conscious processes, this study provides a novel understanding of older adults' PA. Interventions aiming to promote PA behaviour of older adults should target the combination of psychological processes.

Dual-mode fluorophore-doped nickel nitrilotriacetic acid-modified silica nanoparticles combine histidine-tagged protein purification with site-specific fluorophore labeling.

Science.gov (United States)

Kim, Sung Hoon; Jeyakumar, M; Katzenellenbogen, John A

2007-10-31

We present the first example of a fluorophore-doped nickel chelate surface-modified silica nanoparticle that functions in a dual mode, combining histidine-tagged protein purification with site-specific fluorophore labeling. Tetramethylrhodamine (TMR)-doped silica nanoparticles, estimated to contain 700-900 TMRs per ca. 23 nm particle, were surface modified with nitrilotriacetic acid (NTA), producing TMR-SiO2-NTA-Ni2+. Silica-embedded TMR retains very high quantum yield, is resistant to quenching by buffer components, and is modestly quenched and only to a certain depth (ca. 2 nm) by surface-attached Ni2+. When exposed to a bacterial lysate containing estrogen receptor alpha ligand binding domain (ERalpha) as a minor component, these beads showed very high specificity binding, enabling protein purification in one step. The capacity and specificity of these beads for binding a his-tagged protein were characterized by electrophoresis, radiometric counting, and MALDI-TOF MS. ERalpha, bound to TMR-SiO2-NTA-Ni++ beads in a site-specific manner, exhibited good activity for ligand binding and for ligand-induced binding to coactivators in solution FRET experiments and protein microarray fluorometric and FRET assays. This dual-mode type TMR-SiO2-NTA-Ni2+ system represents a powerful combination of one-step histidine-tagged protein purification and site-specific labeling with multiple fluorophore species.

Guided-Mode-Leaky-Mode-Guided-Mode Fiber Interferometer and Its High Sensitivity Refractive Index Sensing Technology

Directory of Open Access Journals (Sweden)

Qi Wang

2016-06-01

Full Text Available A cascaded symmetrical dual-taper Mach-Zehnder interferometer structure based on guided-mode and leaky-mode interference is proposed in this paper. Firstly, the interference spectrum characteristics of interferometer has been analyzed by the Finite Difference-Beam Propagation Method (FD-BPM. When the diameter of taper waist is 20 μm–30 μm, dual-taper length is 1 mm and taper distance is 4 cm–6 cm, the spectral contrast is higher, which is suitable for sensing. Secondly, experimental research on refractive index sensitivity is carried out. A refractive index sensitivity of 62.78 nm/RIU (refractive index unit can achieved in the RI range of 1.3333–1.3792 (0%~25% NaCl solution, when the sensor structure parameters meet the following conditions: diameter of taper waist is 24 μm, dual-taper length is 837 μm and taper distance is 5.5 cm. The spectrum contrast is 0.8 and measurement resolution is 1.6 × 10−5 RIU. The simulation analysis is highly consistent with experimental results. Research shows that the sensor has promising application in low RI fields where high-precision measurement is required due to its high sensitivity and stability.

The Default Mode Network as a Biomarker of Persistent Complaints after Mild Traumatic Brain Injury: A Longitudinal Functional Magnetic Resonance Imaging Study.

Science.gov (United States)

van der Horn, Harm J; Scheenen, Myrthe E; de Koning, Myrthe E; Liemburg, Edith J; Spikman, Jacoba M; van der Naalt, Joukje

2017-12-01

The objective of this study was to examine longitudinal functional connectivity of resting-state networks in patients with and without complaints after uncomplicated mild traumatic brain injury (mTBI). Second, we aimed to determine the value of network connectivity in predicting persistent complaints, anxiety, depression and long-term outcome. Thirty mTBI patients with three or more post-traumatic complaints at 2 weeks post-injury, 19 without complaints, and 20 matched healthy controls were selected for this study. Resting-state functional MRI (fMRI) was performed in patients at 1 month and 3 months post-injury, and once in healthy controls. Independent component analysis (ICA) was used to investigate the default mode, executive and salience networks. Persistent post-traumatic complaints, anxiety, and depression were measured at 3 months post-injury, and outcome was determined at 1 year post-injury. Within the group with complaints, higher functional connectivity between the anterior and posterior components of the default mode network at 1 month post-injury was associated with a greater number of complaints at 3 months post-injury (ρ = 0.59, p = 0.001). Minor longitudinal changes in functional connectivity were found for patients with and without complaints after mTBI, which were limited to connectivity within the precuneus component of the default mode network. No significant results were found for the executive and salience networks. Current results suggest that the default mode network may serve as a biomarker of persistent complaints in patients with uncomplicated mTBI.

Longitudinal and transverse wake potentials in SLAC

International Nuclear Information System (INIS)

Bane, K.; Wilson, P.

1980-01-01

In a machine with short bunches of high peak currents, such as the SLAC collider, one needs to know the longitudinal wake potential, for the higher mode losses, and the transverse wake potential, since, for bunches passing slightly off axis, the induced transverse forces will tend to cause beam break up. The longitudinal and transverse wakes of the SLAC structure presented here, were calculated by computer using the modal method, and including an analytic extension for higher modes. (Auth.)

Adaptive lesion formation using dual mode ultrasound array system

Science.gov (United States)

Liu, Dalong; Casper, Andrew; Haritonova, Alyona; Ebbini, Emad S.

2017-03-01

We present the results from an ultrasound-guided focused ultrasound platform designed to perform real-time monitoring and control of lesion formation. Real-time signal processing of echogenicity changes during lesion formation allows for identification of signature events indicative of tissue damage. The detection of these events triggers the cessation or the reduction of the exposure (intensity and/or time) to prevent overexposure. A dual mode ultrasound array (DMUA) is used for forming single- and multiple-focus patterns in a variety of tissues. The DMUA approach allows for inherent registration between the therapeutic and imaging coordinate systems providing instantaneous, spatially-accurate feedback on lesion formation dynamics. The beamformed RF data has been shown to have high sensitivity and specificity to tissue changes during lesion formation, including in vivo. In particular, the beamformed echo data from the DMUA is very sensitive to cavitation activity in response to HIFU in a variety of modes, e.g. boiling cavitation. This form of feedback is characterized by sudden increase in echogenicity that could occur within milliseconds of the application of HIFU (see http://youtu.be/No2wh-ceTLs for an example). The real-time beamforming and signal processing allowing the adaptive control of lesion formation is enabled by a high performance GPU platform (response time within 10 msec). We present results from a series of experiments in bovine cardiac tissue demonstrating the robustness and increased speed of volumetric lesion formation for a range of clinically-relevant exposures. Gross histology demonstrate clearly that adaptive lesion formation results in tissue damage consistent with the size of the focal spot and the raster scan in 3 dimensions. In contrast, uncontrolled volumetric lesions exhibit significant pre-focal buildup due to excessive exposure from multiple full-exposure HIFU shots. Stopping or reducing the HIFU exposure upon the detection of such an

Trapped Mode Study in the LHC Rotatable Collimator

CERN Document Server

Xiao, L; Smith, J C; Caspers, F

2010-01-01

A rotatable collimator is proposed for the LHC phase II collimation upgrade. When the beam crosses the collimator, trapped modes will be excited that result in beam energy loss and collimator power dissipation. Some of the trapped modes can also generate transverse kick on the beam and affect the beam operation. In this paper the parallel eigensolver code Omega3P is used to search for all the trapped modes below 2GHz in the collimator, including longitudinal modes and transverse modes. The loss factors and kick factors of the trapped modes are calculated as function of the jaw positions. The amplitude ratio between transverse and longitudinal trapped mode intensity can be used as a direct measure of the position of the beam. We present simulation results and discuss the results.

Resting State Default Mode Network Connectivity, Dual Task Performance, Gait Speed, and Postural Sway in Older Adults with Mild Cognitive Impairment.

Science.gov (United States)

Crockett, Rachel A; Hsu, Chun Liang; Best, John R; Liu-Ambrose, Teresa

2017-01-01

Aging is associated with an increased risk of falling. In particular, older adults with mild cognitive impairment (MCI) are more vulnerable to falling compared with their healthy counterparts. Major contributors to this increased falls risk include a decline in dual task performance, gait speed, and postural sway. Recent evidence highlights the potential influence of the default mode network (DMN), the frontoparietal network (FPN), and the supplementary motor area (SMA) on dual task performance, gait speed, and postural sway. The DMN is active during rest and deactivates during task-oriented processes, to maintain attention and stay on task. The FPN and SMA are involved in top-down attentional control, motor planning, and motor execution. The DMN shows less deactivation during task in older adults with MCI. This lack of deactivation is theorized to increase competition for resources between the DMN and task-related brain regions (e.g., the FPN and SMA), increasing distraction from the task and reducing task performance. However, no study has yet investigated the relationship between the between-network connectivity of the DMN with these regions and dual task walking, gait speed or postural sway. We hypothesized that greater functional connectivity both within the DMN and between DMN-FPN and DMN-SMA, will be associated with poorer performance during dual task walking, slower gait speed, and greater postural sway in older adults with MCI. Forty older adults with MCI were measured on a dual task-walking paradigm, gait speed over a 4-m walk, and postural sway using a sway-meter. Greater within-DMN connectivity was significantly correlated with poorer dual task performance. Furthermore, greater inter-network connectivity between the DMN and SMA was significantly correlated with slower gait speed and greater postural sway on the eyes open floor sway task. Thus, greater resting state DMN functional connectivity may be an underlying neural mechanism for reduced dual task

A portable optical emission spectroscopy-cavity ringdown spectroscopy dual-mode plasma spectrometer for measurements of environmentally important trace heavy metals: Initial test with elemental Hg

Science.gov (United States)

Sahay, Peeyush; Scherrer, Susan T.; Wang, Chuji

2012-09-01

A portable optical emission spectroscopy-cavity ringdown spectroscopy (OES-CRDS) dual-mode plasma spectrometer is described. A compact, low-power, atmospheric argon microwave plasma torch (MPT) is utilized as the emission source when the spectrometer is operating in the OES mode. The same MPT serves as the atomization source for ringdown measurements in the CRDS mode. Initial demonstration of the instrument is carried out by observing OES of multiple elements including mercury (Hg) in the OES mode and by measuring absolute concentrations of Hg in the metastable state 6s6p 3P0 in the CRDS mode, in which a palm-size diode laser operating at a single wavelength 405 nm is incorporated in the spectrometer as the light source. In the OES mode, the detection limit for Hg is determined to be 44 parts per 109 (ppb). A strong radiation trapping effect on emission measurements of Hg at 254 nm is observed when the Hg solution concentration is higher than 50 parts per 106 (ppm). The radiation trapping effect suggests that two different transition lines of Hg at 253.65 nm and 365.01 nm be selected for emission measurements in lower (50 ppm), respectively. In the CRDS mode, the detection limit of Hg in the metastable state 6s6p 3P0 is achieved to be 2.24 parts per 1012 (ppt) when the plasma is operating at 150 W with sample gas flow rate of 480 mL min-1; the detection limit corresponds to 50 ppm in Hg sample solution. Advantage of this novel spectrometer has two-fold, it has a large measurement dynamic range, from a few ppt to hundreds ppm and the CRDS mode can serve as calibration for the OES mode as well as high sensitivity measurements. Measurements of seven other elements, As, Cd, Mn, Ni, P, Pb, and Sr, using the OES mode are also carried out with detection limits of 1100, 33, 30, 144, 576, 94, and 2 ppb, respectively. Matrix effect in the presence of other elements on Hg measurements has been found to increase the detection limit to 131 ppb. These elements in lower

Ultrafast spectral dynamics of dual-color-soliton intracavity collision in a mode-locked fiber laser

Science.gov (United States)

Wei, Yuan; Li, Bowen; Wei, Xiaoming; Yu, Ying; Wong, Kenneth K. Y.

2018-02-01

The single-shot spectral dynamics of dual-color-soliton collisions inside a mode-locked laser is experimentally and numerically investigated. By using the all-optically dispersive Fourier transform, we spectrally unveil the collision-induced soliton self-reshaping process, which features dynamic spectral fringes over the soliton main lobe, and the rebuilding of Kelly sidebands with wavelength drifting. Meanwhile, the numerical simulations validate the experimental observation and provide additional insights into the physical mechanism of the collision-induced spectral dynamics from the temporal domain perspective. It is verified that the dynamic interference between the soliton and the dispersive waves is responsible for the observed collision-induced spectral evolution. These dynamic phenomena not only demonstrate the role of dispersive waves in the sophisticated soliton interaction inside the laser cavity, but also facilitate a deeper understanding of the soliton's inherent stability.

Animacroxam, a Novel Dual-Mode Compound Targeting Histone Deacetylases and Cytoskeletal Integrity of Testicular Germ Cell Cancer Cells.

Science.gov (United States)

Steinemann, Gustav; Dittmer, Alexandra; Kuzyniak, Weronika; Hoffmann, Björn; Schrader, Mark; Schobert, Rainer; Biersack, Bernhard; Nitzsche, Bianca; Höpfner, Michael

2017-11-01

Novel approaches for the medical treatment of advanced solid tumors, including testicular germ cell tumors (TGCT), are desperately needed. Especially, TGCT patients not responding to cisplatin-based therapy need therapeutic alternatives, as there is no effective medical treatment available for this particular subgroup. Here, we studied the suitability of the novel dual-mode compound animacroxam for TGCT treatment. Animacroxam consists of an HDAC-inhibitory hydroxamate moiety coupled to a 4,5-diarylimidazole with inherent cytoskeleton disrupting potency. Animacroxam revealed pronounced antiproliferative, cell-cycle arresting, and apoptosis-inducing effects in TGCT cell lines with different cisplatin sensitivities. The IC 50 values of animacroxam ranged from 0.22 to 0.42 μmol/L and were not correlated to the cisplatin sensitivity of the tumor cells. No unspecific cytotoxicity of animacroxam was observed in either cisplatin-sensitive or resistant TGCT cells, even at doses as high as 10 μmol/L. Furthermore, animacroxam induced the formation of actin stress fibers in cancer cells, thereby confirming the cytoskeleton-disrupting and antimigratory properties of its imidazole moiety. When compared with the clinically established HDAC inhibitor vorinostat, the novel dual-mode compound animacroxam exhibited superior antitumoral efficacy in vitro Animacroxam also reduced the tumor size of TGCT tumors in vivo , as evidenced by performing xenograft experiments on tumor bearing chorioallantoic membranes of fertilizes chicken eggs (CAM assay). The in vivo experiments also revealed a very good tolerability of the compound, and hence, animacroxam may be a promising candidate for innovative treatment of TGCT in general and the more so for platinum-insensitive or refractory TGCT. Mol Cancer Ther; 16(11); 2364-74. ©2017 AACR . ©2017 American Association for Cancer Research.

Operating modes and practical power flow analysis of bidirectional isolated power interface for distributed power systems

International Nuclear Information System (INIS)

Wen, Huiqing; Su, Bin

2016-01-01

Highlights: • Four operating modes of Dual-Phase-Shift control for Dual Active Bridge converter are presented. • Effects of “minor parameters” such as the deadtime and power device voltage drops are analyzed. • Accurate power flow models with Dual-Phase-Shift control are developed and verified with experimental results. • Optimal operating mode is determined with respect to the efficiency improvement. • Measured efficiency of the Dual Active Bridge converter is improved up to 14%. - Abstract: Due to the intermittent nature of the renewable energy sources including photovoltaic and wind energy, the energy storage systems are essential to stabilize dc bus voltage. Considering the discharge depth of super-capacitors and energy-storage batteries, the bidirectional isolated power interface will operate for a wide range of voltage and power. This study focuses on in-depth analysis of the dual-active-bridge dc–dc converter that is controlled by the dual-phase-shift scheme to improve the conversion efficiency in distributed power system. The power flow of each operating mode with dual-phase-shift control is characterized based on a detailed analysis of the effects of “minor parameters”, including the deadtime and power device voltage drops. The complete output power plane of the dual-active-bridge converter with dual-phase-shift control is obtained and compared with experimental results. The optimal operating mode is determined according to the practical output power range and the power flow characteristics. Experimental evaluation shows the effectiveness of the proposed power flow model with dual-phase-shift control and significant efficiency improvement using the optimal mode of dual-phase-shift compared with the conventional phase shift control.

High-temperature superconducting coplanar-waveguide quarter-wavelength resonator with odd- and even-mode resonant frequencies for dual-band bandpass filter

Energy Technology Data Exchange (ETDEWEB)

Satoh, Kei; Takagi, Yuta; Narahashi, Shoichi [Research Laboratories, NTT DOCOMO, INC., 3-6 Hikari-no-oka Yokosuka, Kanagawa 239-8536 Japan (Japan); Nojima, Toshio, E-mail: satokei@nttdocomo.co.j [Graduate School of Information Science and Technology, Hokkaido University, Kita 14, Nishi 9, Kita-ku, Sapporo, Hokkaido 060-0814 Japan (Japan)

2010-06-01

This paper presents a high-temperature superconducting coplanar-waveguide quarter-wavelength resonator that has two different resonant modes for use in a dual-band bandpass filter (DBPF). An RF filter with multiple passbands such as the DBPF is a basic element that is expected to achieve broadband transmission by using separated frequency bands aggregately and simultaneously in future mobile communication systems. The proposed resonator has a folded center conductor and two open stubs that are aligned close to it. The odd- and even-mode resonant frequencies are configured using the space between the folded center conductor and the open stubs. It is easy to configure the odd- and even-mode coupling coefficients independently because the two resonant modes have different current density distributions. Consequently, a DBPF with two different bandwidths can be easily designed. This paper presents three design examples for a four-pole Chebyshev DBPF with different combinations of fractional bandwidths in order to investigate the validity of the proposed resonator. This paper also presents measured results of the DBPF based on the design examples from the standpoint of experimental investigation. The designed and measured frequency responses confirm that the proposed resonator is effective in achieving DBPFs not only with two of the same bandwidths but also with two different bandwidths.

Simulation and experimental study on transportation of dual-beam guided by confining magnetic-field

International Nuclear Information System (INIS)

Bai Xianchen; Zhang Jiande; Yang Jianhua

2008-01-01

Using external longitudinal magnetic-field to guide dual-beam out of the dual-shift tubes is a key step for the practicality of synchronizing dual-beam produced by a single accelerator. On the basis of the simulation of the confining magnetic-field for the solid dual-beam, the experiment of magnetic-field guiding annular dual-beam was presented. When the diode voltage was 380 kV, dual-beam currents of 5.10 kA and 4.92 kA were obtained. The experimental results indicate that the designed magnetic-field system could confine the annular dual-beam effectively, and the critical confining magnetic-field is about 0.5 T. (authors)

Yb3+,Er3+,Eu3+-codoped YVO4 material for bioimaging with dual mode excitation

International Nuclear Information System (INIS)

Thao, Chu Thi Bich; Huy, Bui The; Sharipov, Mirkomil; Kim, Jin-Ik.; Dao, Van-Duong; Moon, Ja-Young; Lee, Yong-Ill

2017-01-01

We propose an efficient bioimaging strategy using Yb 3+ ,Er 3+ ,Eu 3+ -triplet doped YVO 4 nanoparticles which were synthesized with polymer as a template. The obtained particles possess nanoscale, uniform, and flexible excitation. The effect of Eu 3+ ions on the luminescence properties of YVO 4 :Yb 3+ ,Er 3+ ,Eu 3+ was investigated. The upconversion mechanism of the prepared material was also discussed. The structure and optical properties of the prepared material were characterized by using X-ray diffraction (XRD), Fourier-transform IR spectroscopy (FTIR), scanning electron microscopy (SEM), Transmission electron microscopy (TEM) upconversion and photoluminescence spectra. The Commission International de I′Eclairage (CIE) chromaticity coordinates was investigated to confirm the performance of color luminescent emission. The prepared YVO 4 :Yb 3+ ,Er 3+ ,Eu 3+ nanoparticles could be easily dispersed in water by surface modification with cysteine (Cys) and glutathione (GSH). The aqueous dispersion of the modified YVO 4 :Yb 3+ ,Er 3+ ,Eu 3+ exhibits bright upconversion and downconversion luminescence and has been applied for bioimaging of HeLa cells. Our developed material with dual excitation offers a promising advance in bioimaging. - Highlights: • Prepared particles possess nanoscale size, uniform, and larger scale. • The material exhibits strong emission under dual mode excitations. • The surface material has been applied for bioimaging of HeLa cell. • Low cytotoxicity, no auto-fluorescence

Design of a search and rescue terminal based on the dual-mode satellite and CDMA network

Science.gov (United States)

Zhao, Junping; Zhang, Xuan; Zheng, Bing; Zhou, Yubin; Song, Hao; Song, Wei; Zhang, Meikui; Liu, Tongze; Zhou, Li

2010-12-01

The current goal is to create a set of portable terminals with GPS/BD2 dual-mode satellite positioning, vital signs monitoring and wireless transmission functions. The terminal depends on an ARM processor to collect and combine data related to vital signs and GPS/BD2 location information, and sends the message to headquarters through the military CDMA network. It integrates multiple functions as a whole. The satellite positioning and wireless transmission capabilities are integrated into the motherboard, and the vital signs sensors used in the form of belts communicate with the board through Bluetooth. It can be adjusted according to the headquarters' instructions. This kind of device is of great practical significance for operations during disaster relief, search and rescue of the wounded in wartime, non-war military operations and other special circumstances.

Requirements for longitudinal HOM damping in superconducting recirculating linacs

International Nuclear Information System (INIS)

Bisognano, J.J.; Fripp, M.L.

1989-01-01

Transverse beam breakup provides the primary current limitation in the operation of superconducting recirculating linacs and requires the significant damping of transverse-deflecting higher order modes. The need to damp the coexisting longitudinal HOMs in these nominally isochronous machines, however, is not as clear. Isochronicity implies that energy variations induced by excitation of longitudinal modes do not translate directly into position and current modulations. Such modulations, if present, could enhance the initial excitation, effectively closing a potentially unstable feedback loop. Design optimization of cavity structures may suggest that no longitudinal damping be provided. On the other hand, easing of the isochronicity requirement may provide desired flexibility in lattice design. In this note, limits are placed on the requirements for longitudinal HOM damping and on the tolerances for isochronicity which are driven by possible longitudinal multipass phenomena. 2 refs., 1 fig

A new dual injection system for AMS facility

International Nuclear Information System (INIS)

Liu Lin; Zhou Weijian; Cheng Peng; Yu Huagui; Chen Maobai

2007-01-01

In order to measure long-lived radioisotopes such as 10 Be with high sensitivity using an HVEE model 4130 AMS system, as well as to guarantee 14 C measurements of high precision, a new dual injection system for the AMS system is proposed. The proposal is to add a Wien filter located between the ion source system and the recombinator of the HVEE model 4130. When a pulsing voltage is optionally applied to the Wien filter, a sequential injection mode is turned on. The isotopes would alternately pass on different trajectories through the recombinator. When the pulsing voltage and magnetic field are turned off, the Wien filter acts as a field-free drift space and the standard simultaneous injection mode is on. Beam optics calculation show that the new dual injection system will increase the number of radio-nuclides which can be analyzed, keep the high precision capability for radiocarbon dating and achieve high sensitivity for 10 Be and 26 Al measurements, together with simplifying the layout as compared to existing dual-injector and dual high-energy beam line systems

Dual Mode Sensing with Low-Profile Piezoelectric Thin Wafer Sensors for Steel Bridge Crack Detection and Diagnosis

Directory of Open Access Journals (Sweden)

Lingyu Yu

2012-01-01

Full Text Available Monitoring of fatigue cracking in steel bridges is of high interest to many bridge owners and agencies. Due to the variety of deterioration sources and locations of bridge defects, there is currently no single method that can detect and address the potential sources globally. In this paper, we presented a dual mode sensing methodology integrating acoustic emission and ultrasonic wave inspection based on the use of low-profile piezoelectric wafer active sensors (PWAS. After introducing the research background and piezoelectric sensing principles, PWAS crack detection in passive acoustic emission mode is first presented. Their acoustic emission detection capability has been validated through both static and compact tension fatigue tests. With the use of coaxial cable wiring, PWAS AE signal quality has been improved. The active ultrasonic inspection is conducted by the damage index and wave imaging approach. The results in the paper show that such an integration of passive acoustic emission detection with active ultrasonic sensing is a technological leap forward from the current practice of periodic and subjective visual inspection and bridge management based primarily on history of past performance.

Coherent cavity-enhanced dual-comb spectroscopy

OpenAIRE

Fleisher, Adam J.; Long, David A.; Reed, Zachary D.; Hodges, Joseph T.; Plusquellic, David F.

2016-01-01

Dual-comb spectroscopy allows for the rapid, multiplexed acquisition of high-resolution spectra without the need for moving parts or low-resolution dispersive optics. This method of broadband spectroscopy is most often accomplished via tight phase locking of two mode-locked lasers or via sophisticated signal processing algorithms, and therefore, long integration times of phase coherent signals are difficult to achieve. Here we demonstrate an alternative approach to dual-comb spectroscopy usin...

Stable single longitudinal mode erbium-doped silica fiber laser based on an asymmetric linear three-cavity structure

International Nuclear Information System (INIS)

Feng Ting; Yan Feng-Ping; Li Qi; Peng Wan-Jing; Feng Su-Chun; Tan Si-Yu; Wen Xiao-Dong

2013-01-01

We present a stable linear-cavity single longitudinal mode (SLM) erbium-doped silica fiber laser. It consists of four fiber Bragg gratings (FBGs) directly written in a section of photosensitive erbium-doped fiber (EDF) to form an asymmetric three-cavity structure. The stable SLM operation at a wavelength of 1545.112 nm with a 3-dB bandwidth of 0.012 nm and an optical signal-to-noise ratio (OSNR) of about 60 dB is verified experimentally. Under laboratory conditions, the performance of a power fluctuation of less than 0.05 dB observed from the power meter for 6 h and a wavelength variation of less than 0.01 nm obtained from the optical spectrum analyzer (OSA) for about 1.5 h are demonstrated. The gain fiber length is no longer limited to only several centimeters for SLM operation because of the excellent mode-selecting ability of the asymmetric three-cavity structure. The proposed scheme provides a simple and cost-effective approach to realizing a stable SLM fiber laser. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

Plasmon-polariton modes of dense Au nanowire arrays

Energy Technology Data Exchange (ETDEWEB)

Yan, Hongdan; Lemmens, Peter; Wulferding, Dirk; Cetin, Mehmet Fatih [IPKM, TU-BS, Braunschweig (Germany); Tornow, Sabine; Zwicknagl, Gertrud [IMP, TU-BS, Braunschweig (Germany); Krieg, Ulrich; Pfnuer, Herbert [IFP, LU Hannover (Germany); Daum, Winfried; Lilienkamp, Gerhard [IEPT, TU Clausthal (Germany); Schilling, Meinhard [EMG, TU-BS, Braunschweig (Germany)

2011-07-01

Using optical absorption and other techniques we study plasmon-polariton modes of dense Au nanowire arrays as function of geometrical parameters and coupling to molecular degrees of freedom. For this instance we electrochemically deposit Au nanowires in porous alumina with well controlled morphology and defect concentration. Transverse and longitudinal modes are observed in the absorption spectra resulting from the anisotropic plasmonic structure. The longitudinal mode shows a blue shift of energy with increasing length of the wires due to the more collective nature of this response. We compare our observations with model calculations and corresponding results on 2D Ag nanowire lattices.

Studies of longitudinal profile of electron bunches and impedance measurements at Indus-2 synchrotron radiation source

Energy Technology Data Exchange (ETDEWEB)

Garg, Akash Deep, E-mail: akash-deep@rrcat.gov.in [Beam Diagnostics Section (BDS), Indus Operations, Beam Dynamics and Diagnostics Division (IOBDD), Raja Ramanna Centre for Advanced Technology, Indore 452 013, M.P. (India); Homi Bhabha National Institute (HBNI) at Raja Ramanna Centre for Advanced Technology, Indore (India); Yadav, S.; Kumar, Mukesh; Shrivastava, B.B.; Karnewar, A.K.; Ojha, A.; Puntambekar, T.A. [Beam Diagnostics Section (BDS), Indus Operations, Beam Dynamics and Diagnostics Division (IOBDD), Raja Ramanna Centre for Advanced Technology, Indore 452 013, M.P. (India)

2016-04-01

Indus-2 is a 3rd generation synchrotron radiation source at the Raja Ramanna Centre for Advanced Technology (RRCAT) in India. We study the longitudinal profile of electrons in Indus-2 by using dual sweep synchroscan streak camera at visible diagnostic beamline. In this paper, the longitudinal profiles of electron bunch are analyzed by filling beam current in a single bunch mode. These studies are carried at injection energy (550 MeV) and at ramped beam energy (2.5 GeV). The effects of the wakefield generated interactions between the circulating electrons and the surrounding vacuum chamber are analyzed in terms of measured effects on longitudinal beam distribution. The impedance of the storage ring is obtained by fitting the solutions of Haissinski equation to the measured bunch lengthening with different impedance models. The impedance of storage ring obtained by a series R+L impedance model indicates a resistance (R) of 1350±125 Ω, an inductance (L) of 180±25 nH and broadband impedance of 2.69 Ω. These results are also compared with the values obtained from measured synchronous phase advancing and scaling laws. These studies are very useful in better understanding and control of the electromagnetic interactions.

Comb-Resolved Dual-Comb Spectroscopy Stabilized by Free-Running Continuous-Wave Lasers

Science.gov (United States)

Kuse, Naoya; Ozawa, Akira; Kobayashi, Yohei

2012-11-01

We demonstrate dual-comb spectroscopy with relatively phase-locked two frequency combs, instead of frequency combs firmly fixed to the absolute frequency references. By stabilizing two beat frequencies between two mode-locked lasers at different wavelengths observed via free-running continuous-wave (CW) lasers, two combs are tightly phase locked to each other. The frequency noise of the CW lasers barely affects the performance of dual-comb spectroscopy because of the extremely fast common-mode noise rejection. Transform-limited comb-resolved dual-comb spectroscopy with a 6 Hz radio frequency linewidth is demonstrated by the use of Yb-fiber oscillators.

Liquid-phase sample preparation method for real-time monitoring of airborne asbestos fibers by dual-mode high-throughput microscopy.

Science.gov (United States)

Cho, Myoung-Ock; Kim, Jung Kyung; Han, Hwataik; Lee, Jeonghoon

2013-01-01

Asbestos that had been used widely as a construction material is a first-level carcinogen recognized by the World Health Organization. It can be accumulated in body by inhalation causing virulent respiratory diseases including lung cancer. In our previous study, we developed a high-throughput microscopy (HTM) system that can minimize human intervention accompanied by the conventional phase contrast microscopy (PCM) through automated counting of fibrous materials and thus significantly reduce analysis time and labor. Also, we attempted selective detection of chrysotile using DksA protein extracted from Escherichia coli through a recombinant protein production technique, and developed a dual-mode HTM (DM-HTM) by upgrading the HTM device. We demonstrated that fluorescently-labeled chrysotile asbestos fibers can be identified and enumerated automatically among other types of asbestos fibers or non-asbestos particles in a high-throughput manner through a newly modified HTM system for both reflection and fluorescence imaging. However there is a limitation to apply DM-HTM to airborne sample with current air collecting method due to the difficulty of applying the protein to dried asbestos sample. Here, we developed a technique for preparing liquid-phase asbestos sample using an impinger normally used to collect odor molecules in the air. It would be possible to improve the feasibility of the dual-mode HTM by integrating a sample preparation unit for making collected asbestos sample dispersed in a solution. The new technique developed for highly sensitive and automated asbestos detection can be a potential alternative to the conventional manual counting method, and it may be applied on site as a fast and reliable environmental monitoring tool.

Hyaluronic acid-modified manganese-chelated dendrimer-entrapped gold nanoparticles for the targeted CT/MR dual-mode imaging of hepatocellular carcinoma

Science.gov (United States)

Wang, Ruizhi; Luo, Yu; Yang, Shuohui; Lin, Jiang; Gao, Dongmei; Zhao, Yan; Liu, Jinguo; Shi, Xiangyang; Wang, Xiaolin

2016-09-01

Hepatocellular carcinoma (HCC) is the most common malignant tumor of the liver. The early and effective diagnosis has always been desired. Herein, we present the preparation and characterization of hyaluronic acid (HA)-modified, multifunctional nanoparticles (NPs) targeting CD44 receptor-expressing cancer cells for computed tomography (CT)/magnetic resonance (MR) dual-mode imaging. We first modified amine-terminated generation 5 poly(amidoamine) dendrimers (G5.NH2) with an Mn chelator, 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), fluorescein isothiocyanate (FI), and HA. Then, gold nanoparticles (AuNPs) were entrapped within the above raw product, denoted as G5.NH2-FI-DOTA-HA. The designed multifunctional NPs were formed after further Mn chelation and purification and were denoted as {(Au0)100G5.NH2-FI-DOTA(Mn)-HA}. These NPs were characterized via several different techniques. We found that the {(Au0)100G5.NH2-FI-DOTA(Mn)-HA} NPs exhibited good water dispersibility, stability under different conditions, and cytocompatibility within a given concentration range. Because both AuNPs and Mn were present in the product, {(Au0)100G5.NH2-FI-DOTA(Mn)-HA} displayed a high X-ray attenuation intensity and favorable r1 relaxivity, which are advantageous properties for targeted CT/MR dual-mode imaging. This approach was used to image HCC cells in vitro and orthotopically transplanted HCC tumors in a unique in vivo model through the CD44 receptor-mediated endocytosis pathway. This work introduces a novel strategy for preparing multifunctional NPs via dendrimer nanotechnology.

Low-order longitudinal modes of single-component plasmas

International Nuclear Information System (INIS)

Tinkle, M.D.; Greaves, R.G.; Surko, C.M.

1995-01-01

The low-order modes of spheroidal, pure electron plasmas have been studied experimentally, both in a cylindrical electrode structure and in a quadrupole trap. Comparison is made between measurements of mode frequencies, recent analytical theories, and numerical simulations. Effects considered include trap anharmonicity, image charges, and temperature. Quantitative agreement is obtained between the predictions and these measurements for spheroidal plasmas in the quadrupole trap. In many experiments on single-component plasmas, including antimatter plasmas, the standard diagnostic techniques used to measure the density and temperature are not appropriate. A new method is presented for determining the size, shape, average density, and temperature of a plasma confined in a Penning trap from measurements of the mode frequencies. copyright 1995 American Institute of Physics

Study of fuzzy adaptive PID controller on thermal frequency stabilizing laser with double longitudinal modes

Science.gov (United States)

Mo, Qingkai; Zhang, Tao; Yan, Yining

2016-10-01

There are contradictions among speediness, anti-disturbance performance, and steady-state accuracy caused by traditional PID controller in the existing light source systems of thermal frequency stabilizing laser with double longitudinal modes. In this paper, a new kind of fuzzy adaptive PID controller was designed by combining fuzzy PID control technology and expert system to make frequency stabilizing system obtain the optimal performance. The experiments show that the frequency stability of the designed PID controller is similar to the existing PID controller (the magnitude of frequency stability is less than 10-9 in constant temperature and 10-7 in open air). But the preheating time is shortened obviously (from 10 minutes to 5 minutes) and the anti-disturbance capability is improved significantly (the recovery time needed after strong interference is reduced from 1 minute to 10 seconds).

Stability of longitudinal bunch length feedback for heavy-ion synchrotrons

Directory of Open Access Journals (Sweden)

D. Lens

2013-03-01

Full Text Available In heavy-ion synchrotrons such as the SIS18 at Helmholtzzentrum für Schwerionenforschung, Helmholtz Centre for Heavy Ion Research (GSI, coherent oscillations of the particle bunches are damped by rf feedback systems to increase the stability and to improve the beam quality. In the longitudinal direction, important modes are the coherent longitudinal dipole and quadrupole oscillation. In this paper we present a new and rigorous approach to analyze the longitudinal feedback to damp these modes. The results are applied to the rf feedback loop at GSI that damps the quadrupole mode. The stability analysis is compared with simulations and is in good agreement with results of a beam experiment. Finally, we summarize practical implications for the operation of the feedback system regarding performance and stability.

Dual THz comb spectroscopy

Science.gov (United States)

Yasui, Takeshi

2017-08-01

Optical frequency combs are innovative tools for broadband spectroscopy because a series of comb modes can serve as frequency markers that are traceable to a microwave frequency standard. However, a mode distribution that is too discrete limits the spectral sampling interval to the mode frequency spacing even though individual mode linewidth is sufficiently narrow. Here, using a combination of a spectral interleaving and dual-comb spectroscopy in the terahertz (THz) region, we achieved a spectral sampling interval equal to the mode linewidth rather than the mode spacing. The spectrally interleaved THz comb was realized by sweeping the laser repetition frequency and interleaving additional frequency marks. In low-pressure gas spectroscopy, we achieved an improved spectral sampling density of 2.5 MHz and enhanced spectral accuracy of 8.39 × 10-7 in the THz region. The proposed method is a powerful tool for simultaneously achieving high resolution, high accuracy, and broad spectral coverage in THz spectroscopy.

Agreement and precision of periprosthetic bone density measurements in micro-CT, single and dual energy CT.

Science.gov (United States)

Mussmann, Bo; Overgaard, Søren; Torfing, Trine; Traise, Peter; Gerke, Oke; Andersen, Poul Erik

2017-07-01

The objective of this study was to test the precision and agreement between bone mineral density measurements performed in micro CT, single and dual energy computed tomography, to determine how the keV level influences density measurements and to assess the usefulness of quantitative dual energy computed tomography as a research tool for longitudinal studies aiming to measure bone loss adjacent to total hip replacements. Samples from 10 fresh-frozen porcine femoral heads were placed in a Perspex phantom and computed tomography was performed with two acquisition modes. Bone mineral density was calculated and compared with measurements derived from micro CT. Repeated scans and dual measurements were performed in order to measure between- and within-scan precision. Mean density difference between micro CT and single energy computed tomography was 72 mg HA/cm 3 . For dual energy CT, the mean difference at 100 keV was 128 mg HA/cm 3 while the mean difference at 110-140 keV ranged from -84 to -67 mg HA/cm 3 compared with micro CT. Rescanning the samples resulted in a non-significant overall between-scan difference of 13 mg HA/cm 3 . Bland-Altman limits of agreement were wide and intraclass correlation coefficients ranged from 0.29 to 0.72, while 95% confidence intervals covered almost the full possible range. Repeating the density measurements for within-scan precision resulted in ICCs >0.99 and narrow limits of agreement. Single and dual energy quantitative CT showed excellent within-scan precision, but poor between-scan precision. No significant density differences were found in dual energy quantitative CT at keV-levels above 110 keV. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1470-1477, 2017. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Microresonator soliton dual-comb spectroscopy

Science.gov (United States)

Suh, Myoung-Gyun; Yang, Qi-Fan; Yang, Ki Youl; Yi, Xu; Vahala, Kerry J.

2016-11-01

Measurement of optical and vibrational spectra with high resolution provides a way to identify chemical species in cluttered environments and is of general importance in many fields. Dual-comb spectroscopy has emerged as a powerful approach for acquiring nearly instantaneous Raman and optical spectra with unprecedented resolution. Spectra are generated directly in the electrical domain, without the need for bulky mechanical spectrometers. We demonstrate a miniature soliton-based dual-comb system that can potentially transfer the approach to a chip platform. These devices achieve high-coherence pulsed mode locking. They also feature broad, reproducible spectral envelopes, an essential feature for dual-comb spectroscopy. Our work shows the potential for integrated spectroscopy with high signal-to-noise ratios and fast acquisition rates.

RADIOISOTOPE-DRIVEN DUAL-MODE PROPULSION SYSTEM FOR CUBESAT-SCALE PAYLOADS TO THE OUTER PLANETS

Energy Technology Data Exchange (ETDEWEB)

N. D. Jerred; T. M. Howe; S. D. Howe; A. Rajguru

2014-02-01

It is apparent the cost of planetary exploration is rising as mission budgets declining. Currently small scientific beds geared to performing limited tasks are being developed and launched into low earth orbit (LEO) in the form of small-scale satellite units, i.e., CubeSats. These micro- and nano-satellites are gaining popularity among the university and science communities due to their relatively low cost and design flexibility. To date these small units have been limited to performing tasks in LEO utilizing solar-based power. If a reasonable propulsion system could be developed, these CubeSat platforms could perform exploration of various extra-terrestrial bodies within the solar system engaging a broader range of researchers. Additionally, being mindful of mass, smaller cheaper launch vehicles (approximately 1,000 kgs to LEO) can be targeted. Thus, in effect, allows for beneficial exploration to be conducted within limited budgets. Researchers at the Center for Space Nuclear Research (CSNR) are proposing a low mass, radioisotope-based, dual-mode propulsion system capable of extending the exploration realm of these CubeSats out of LEO.

Cross-mode bioelectrical impedance analysis in a standing position for estimating fat-free mass validated against dual-energy x-ray absorptiometry.

Science.gov (United States)

Huang, Ai-Chun; Chen, Yu-Yawn; Chuang, Chih-Lin; Chiang, Li-Ming; Lu, Hsueh-Kuan; Lin, Hung-Chi; Chen, Kuen-Tsann; Hsiao, An-Chi; Hsieh, Kuen-Chang

2015-11-01

Bioelectrical impedance analysis (BIA) is commonly used to assess body composition. Cross-mode (left hand to right foot, Z(CR)) BIA presumably uses the longest current path in the human body, which may generate better results when estimating fat-free mass (FFM). We compared the cross-mode with the hand-to-foot mode (right hand to right foot, Z(HF)) using dual-energy x-ray absorptiometry (DXA) as the reference. We hypothesized that when comparing anthropometric parameters using stepwise regression analysis, the impedance value from the cross-mode analysis would have better prediction accuracy than that from the hand-to-foot mode analysis. We studied 264 men and 232 women (mean ages, 32.19 ± 14.95 and 34.51 ± 14.96 years, respectively; mean body mass indexes, 24.54 ± 3.74 and 23.44 ± 4.61 kg/m2, respectively). The DXA-measured FFMs in men and women were 58.85 ± 8.15 and 40.48 ± 5.64 kg, respectively. Multiple stepwise linear regression analyses were performed to construct sex-specific FFM equations. The correlations of FFM measured by DXA vs. FFM from hand-to-foot mode and estimated FFM by cross-mode were 0.85 and 0.86 in women, with standard errors of estimate of 2.96 and 2.92 kg, respectively. In men, they were 0.91 and 0.91, with standard errors of the estimates of 3.34 and 3.48 kg, respectively. Bland-Altman plots showed limits of agreement of -6.78 to 6.78 kg for FFM from hand-to-foot mode and -7.06 to 7.06 kg for estimated FFM by cross-mode for men, and -5.91 to 5.91 and -5.84 to 5.84 kg, respectively, for women. Paired t tests showed no significant differences between the 2 modes (P > .05). Hence, cross-mode BIA appears to represent a reasonable and practical application for assessing FFM in Chinese populations. Copyright © 2015 Elsevier Inc. All rights reserved.

DUAL MODE OFFERING AS VIABLE APPROACH FOR PROMOTION OF HIGHER EDUCATION IN PAKISTAN

Directory of Open Access Journals (Sweden)

Irshad HUSSAIN

2014-07-01

Full Text Available Pakistan is a developing with 148 universities and degree awarding institutions including public and private sector. The enrolment as given in the National Educational Policy 2009 was up to 5% only. It reflects greater demands of higher/tertiary education and calls for alternative strategic measures for addressing the issue. An innovative approach was necessary to address the issue of access. Therefore, the Islamia University of Bahawalpur –a formal mode university took an innovative initiative to become a dual mode university by establishing an Institute of Distance Education (IDE in 2011. The institute offered along with others, an M.Phill programme in ten disciplines through distance education mode in semester fall 2011. More than eight hundred applications were received by potential learners against 275 seats. However, after test and interview 189 students were enrolled in M.Phill programme in Applied Psychology, Arabic, Education, English, Media Studies, Islamic Studies, Pakistan Studies, History, Persian, and Urdu. In the beginning, the Institute organized an orientation workshop for learners to guide them studying in distance education system. The programme was offered under semester system and the semester was broke up into two halves –mid-term and final term. The respective departments provided learning materials to students whereas the IDE provided instructional booklet. Submission of two assignments was compulsory for the entire semester; one before mid-term and second before final-term workshop/ examination for each of the courses. Similarly, students’ presence in workshops for 24 hours (12 during mid-term and 12 during final-term workshop for one 3-credit hour course was mandatory. Students’ support services were provided through Skype conference, social media and mobile phones. Students necessarily had to give presentations and submit their assignments after checking their similarity index by using turnitin software. At the

Dual-comb spectroscopy of water vapor with a free-running semiconductor disk laser.

Science.gov (United States)

Link, S M; Maas, D J H C; Waldburger, D; Keller, U

2017-06-16

Dual-comb spectroscopy offers the potential for high accuracy combined with fast data acquisition. Applications are often limited, however, by the complexity of optical comb systems. Here we present dual-comb spectroscopy of water vapor using a substantially simplified single-laser system. Very good spectroscopy measurements with fast sampling rates are achieved with a free-running dual-comb mode-locked semiconductor disk laser. The absolute stability of the optical comb modes is characterized both for free-running operation and with simple microwave stabilization. This approach drastically reduces the complexity for dual-comb spectroscopy. Band-gap engineering to tune the center wavelength from the ultraviolet to the mid-infrared could optimize frequency combs for specific gas targets, further enabling dual-comb spectroscopy for a wider range of industrial applications. Copyright © 2017, American Association for the Advancement of Science.

Development and Operation of Dual-Mode Analyzers for Wireless Power Consortium/Power Matters Alliance Wireless Power Systems.

Science.gov (United States)

Um, Keehong

2016-05-01

We have designed a protocol analyzer to be used in wireless power systems and analyzed the operation of wireless chargers defined by standards of Qi of Wireless Power Consortium (WPC) and Power Matters Alliance (PMA) protocols. The integrated circuit (IC, or microchip) developed so far for wireless power transmission is not easily adopted by chargers for specific purposes. A device for measuring the performance of test equipment currently available is required to transform and expand the types of protocol. Since a protocol analyzer with these functions is required, we have developed a device that can analyze the two protocols of WPC and PMA at the same time. As a result of our research, we present a dual-mode system that can analyze the protocols of both WPC and PMA.

Thermal Equilibrium Dynamic Control Based on DPWM Dual-Mode Modulation of High Power NPC Three-Level Inverter

Directory of Open Access Journals (Sweden)

Shi-Zhou Xu

2016-01-01

Full Text Available In some special applications of NPC three-level inverters, such as mine hoist, there exist special conditions of overloading during the whole hoisting process and large overload in starting stage, during which the power-loss calculation of power devices and thermal control are important factors affecting the thermal stability of inverters. The principles of SVPWM and DPWM were described in this paper firstly, based on which the dynamic power losses of the two modulations of hoist in single period were calculated. Secondly, a thermal equilibrium dynamic control based on DPMW dual-mode modulation was proposed, which can switch the modulation dynamically according to the change of dynamic power loss to realize dynamic control of power loss and thermal equilibrium of inverter. Finally, simulation and experiment prove the effectiveness of the proposed strategy.

MIPAS observations of longitudinal oscillations in the mesosphere and the lower thermosphere: climatology of odd-parity daily frequency modes

Directory of Open Access Journals (Sweden)

M. García-Comas

2016-09-01

Full Text Available MIPAS global Sun-synchronous observations are almost fixed in local time. Subtraction of the descending and ascending node measurements at each longitude only includes the longitudinal oscillations with odd daily frequencies nodd from the Sun's perspective at 10:00. Contributions from the background atmosphere, daily-invariant zonal oscillations and tidal modes with even-parity daily frequencies vanish. We have determined longitudinal oscillations in MIPAS temperature with nodd and wavenumber k = 0–4 from the stratosphere to 150 km from April 2007 to March 2012. To our knowledge, this is the first time zonal oscillations in temperature have been derived pole to pole in this altitude range from a single instrument. The major findings are the detection of (1 migrating tides at northern and southern high latitudes; (2 significant k = 1 activity at extratropical and high latitudes, particularly in the Southern Hemisphere; (3 k = 3 and k = 4 eastward-propagating waves that penetrate the lower thermosphere with a significantly larger vertical wavelength than in the mesosphere; and (4 a migrating tide quasi-biennial oscillation in the stratosphere, mesosphere and lower thermosphere. MIPAS global measurements of longitudinal oscillations are useful for testing tide modeling in the mesosphere and lower thermosphere region and as a lower boundary for models extending higher up in the atmosphere.

Frustration of Bragg reflection by cooperative dual-mode interference: a new mode of optical propagation.

Science.gov (United States)

Yariv, A

1998-12-01

A new optical mode of propagation is described, which is the natural eigenmode (supermode) of a fiber (or any optical waveguide) with two cospatial periodic gratings. The mode frustrates the backward Bragg scattering from the grating by destructive interference of its two constituent submodes (which are eigenmodes of a uniform waveguide). It can be used in a new type of spatial mode conversion in optical guides.

Graduates' Perceptions of Learning Affordances in Longitudinal Integrated Clerkships: A Dual-Institution, Mixed-Methods Study.

Science.gov (United States)

Latessa, Robyn A; Swendiman, Robert A; Parlier, Anna Beth; Galvin, Shelley L; Hirsh, David A

2017-09-01

The authors explored affordances that contribute to participants' successful learning in longitudinal integrated clerkships (LICs). This dual-institutional, mixed-methods study included electronic surveys and semistructured interviews of LIC graduates who completed their core clinical (third) year of medical school. These LIC graduates took part in LICs at Harvard Medical School from 2004 to 2013 and the University of North Carolina School of Medicine-Asheville campus from 2009 to 2013. The survey questions asked LIC graduates to rate components of LICs that they perceived as contributing to successful learning. A research assistant interviewed a subset of study participants about their learning experiences. The authors analyzed aggregate data quantitatively and performed a qualitative content analysis on interview data. The graduates reported multiple affordances that they perceive contributed to successful learning in their LIC. The most reported components included continuity and relationships with preceptors, patients, place, and peers, along with integration of and flexibility within the curriculum. As LIC models grow in size and number, and their structures and processes evolve, learners' perceptions of affordances may guide curriculum planning. Further research is needed to investigate to what degree and by what means these affordances support learning in LICs and other models of clinical education.

Coronary artery stent imaging with 128-slice dual-source CT using high-pitch spiral acquisition in a cardiac phantom: comparison with the sequential and low-pitch spiral mode

International Nuclear Information System (INIS)

Wolf, Florian; Loewe, Christian; Plank, Christina; Schernthaner, Ruediger; Bercaczy, Dominik; Lammer, Johannes; Leschka, Sebastian; Goetti, Robert; Marincek, Borut; Alkadhi, Hatem; Homolka, Peter; Friedrich, Guy; Feuchtner, Gudrun

2010-01-01

To evaluate coronary stents in vitro using 128-slice-dual-source computed tomography (CT). Twelve different coronary stents placed in a non-moving cardiac/chest phantom were examined by 128-slice dual-source CT using three CT protocols [high-pitch spiral (HPS), sequential (SEQ) and conventional spiral (SPIR)]. Artificial in-stent lumen narrowing (ALN), visible inner stent area (VIA), artificial in-stent lumen attenuation (ALA) in percent, image noise inside/outside the stent and CTDIvol were measured. Mean ALN was 46% for HPS, 44% for SEQ and 47% for SPIR without significant difference. Mean VIA was similar with 31% for HPS, 30% for SEQ and 33% for SPIR. Mean ALA was, at 5% for HPS, significantly lower compared with -11% for SPIR (p = 0.024), but not different from SEQ with -1%. Mean image noise was significantly higher for HPS compared with SEQ and SPIR inside and outside the stent (p < 0.001). CTDIvol was lower for HPS (5.17 mGy), compared with SEQ (9.02 mGy) and SPIR (55.97 mGy), respectively. The HPS mode of 128-slice dual-source CT yields fewer artefacts inside the stent lumen compared with SPIR and SEQ, but image noise is higher. ALN is still too high for routine stent evaluation in clinical practice. Radiation dose of the HPS mode is markedly (less than about tenfold) reduced. (orig.)

The dual exo/endo-type mode and the effect of ionic strength on the mode of catalysis of chitinase 60 (CHI60) from Serratia sp. TU09 and its mutants.

Science.gov (United States)

Kuttiyawong, K; Nakapong, S; Pichyangkura, R

2008-11-03

Mutations of the tryptophan residues in the tryptophan-track of the N-terminal domain (W33F/Y and W69F/Y) and in the catalytic domain (W245F/Y) of Serratia sp. TU09 Chitinase 60 (CHI60) were constructed, as single and double point substitutions to either phenylalanine or tyrosine. The enzyme-substrate interaction and mode of catalysis, exo/endo-type, of wild type CHI60 and mutant enzymes on soluble (partially N-acetylated chitin), amorphous (colloidal chitin), and crystalline (β-chitin) substrates were studied. All CHI60 mutants exhibited a reduced substrate binding activity on colloidal chitin. CHI60 possesses a dual mode of catalysis with both exo- and endo-type activities allowing the enzyme to work efficiently on various substrate types. CHI60 preferentially uses the endo-type mode on soluble and amorphous substrates and the exo-type mode on crystalline substrate. However, the prevalent mode of hydrolysis mediated by CHI60 is regulated by ionic strength. Slightly elevated ionic strength, 0.1-0.2M NaCl, which promotes enzyme-substrate interactions, enhances CHI60 hydrolytic activity on amorphous substrate and, interestingly, on partially N-acetylated chitin. High ionic strength, 0.5-2.0M NaCl, prevents the enzyme from dissociating from amorphous substrate, occupying the enzyme in an enzyme-substrate non-productive complex. However, on crystalline substrates, the activity of CHI60 was only inhibited approximately 50% at high ionic strength, suggesting that the enzyme hydrolyzes crystalline substrates with an exo-type mode processively while remaining tightly bound to the substrate. Moreover, substitution of Trp-33 to either phenylalanine or tyrosine reduced the activity of the enzyme at high ionic strength, suggesting an important role of Trp-33 on enzyme processivity.

What Works Clearinghouse Quick Review: "The Impact of Dual Enrollment on College Degree Attainment: Do Low-SES Students Benefit?"

Science.gov (United States)

What Works Clearinghouse, 2013

2013-01-01

This study reviewed in this report used data from the National Education Longitudinal Study (NELS:88) to examine the effects of dual enrollment programs for high school students on college degree attainment. The study further reported on whether the impacts of dual enrollment were different for first generation college students. Dual enrollment…

Compact Dual-Band Bandpass Filter Using Stubs Loaded Ring Resonator

Science.gov (United States)

Xu, Jin

2016-01-01

This paper presents a novel second-order dual-band bandpass filter (BPF) by using proposed stubs loaded ring resonator. The resonant behavior of proposed stubs loaded ring resonator is analyzed by even-/odd-mode method, which shows its multiple-mode resonant characteristic. Parameters sweep is done so as to give the design guidelines. As an example, a second-order dual-band BPF operating at 1.8/5.2 GHz for GSM and WLAN applications is designed, fabricated and measured. The fabricated filter has a very compact size of 0.05λg×0.15λg. Measured results also show that the proposed dual-band BPF has a better than 20 dB rejection upper stopband from 5.47 GHz to 12.56 GHz. Good agreement is shown between the simulated and measured results.

A New Kicker for the TLS Longitudinal Feedback System

CERN Document Server

Lau, Wai-Keung; Dehler, Micha; Hsu, Kuo-Tung; Hsu, San-Yuang; Jung Chou Ping; Wei Chen, Cheng; Yang Chen Huan; Yang Tze Te

2005-01-01

A new longitudinal kicker that is modified from the Swiss Light Source (SLS) design to fit into the TLS storage ring. It will be served as the actuator in the longitudinal multi-bunch feedback control loop. Beam coupling impedance has been calculated by Gdfidl with a PC cluster. Previous to the installation of this new kicker, bench measurement has been performed in the laboratory to characterize this new kicker. The experimental setups for bandwidth and coaxial wire measurement of longitudinal coupling impedance and their corresponding test results will be reported. As a cross check, bead-pull measurement has also been done to verify the beam coupling measurement by coaxial wire method at the kicker center frequency. Longitudinal field profile of the accelerating mode along the beam path has also been mapped. High order cavity modes of the kicker have also been observed and their effects on the beam are evaluated.

Cavity mode control in side-coupled periodic waveguides: theory and experiment

DEFF Research Database (Denmark)

Ha, Sangwoo; Sukhorukov, A.; Lavrinenko, Andrei

2010-01-01

We demonstrate that the modes of coupled cavities created in periodic waveguides can depend critically on the longitudinal shift between the cavities. In the absence of such shift, the modes feature symmetric or antisymmetric profiles, and their frequency splitting generally increases...... as the cavities are brought closer. We show that the longitudinal shift enables flexible control over the fundamental modes, whose frequency detuning can be reduced down to zero. Our coupled-mode theory analysis reveals an intrinsic link between the mode tuning and the transformation of slow-light dispersion...... at the photonic band-edge.We illustrate our approach through numerical modeling of cavities created in arrays of dielectric rods, and confirm our predictions with experimental observations....

Widely tunable single-/dual-wavelength fiber lasers with ultra-narrow linewidth and high OSNR using high quality passive subring cavity and novel tuning method.

Science.gov (United States)

Feng, Ting; Ding, Dongliang; Yan, Fengping; Zhao, Ziwei; Su, Hongxin; Yao, X Steve

2016-08-22

High stability single- and dual-wavelength compound cavity erbium-doped fiber lasers (EDFLs) with ultra-narrow linewidth, high optical signal to noise ratio (OSNR) and widely tunable range are demonstrated. Different from using traditional cascaded Type-1/Type-2 fiber rings as secondary cavities, we nest a Type-1 ring inside a Type-2 ring to form a passive subring cavity to achieve single-longitudinal-mode (SLM) lasing with ultra-narrow linewidth for the first time. We also show that the SLM lasing stability can be further improved by inserting a length of polarization maintaining fiber in the Type-2 ring. Using a uniform fiber Bragg grating (FBG) and two superimposed FBGs as mode restricting elements, respectively, we obtain a single-wavelength EDFL with a linewidth as narrow as 715 Hz and an OSNR as high as 73 dB, and a dual-wavelength EDFL with linewidths less than 1 kHz and OSNRs higher than 68 dB for both lasing wavelengths. Finally, by employing a novel self-designed strain adjustment device capable of applying both the compression and tension forces to the FBGs for wavelength tuning, we achieve the tuning range larger than 10 nm for both of the EDFLs.

Evaluation of longitudinal loading of tank trains during motion in longitudinal changes of gradient

Directory of Open Access Journals (Sweden)

S.V. Myamlin

2013-06-01

Full Text Available Purpose. To research the tank train longitudinal loading during motion by track sections with changes of gradient. The trains of different length that consist of bogie tank wagons should be examined. Influence of cargo type on longitudinal loading of train during motion in concave section of track should be evaluated. Methodology. The level of the largest longitudinal forces was estimated by mathematical simulation. It was assumed that change of gradient is formed by two grades with baffle platforms, length 50 meters, so that the algebraic difference of limiting grades vary from 10‰ to 40‰, pitch 10‰. The initial speeds were 40, 60, 80, 100, 120 km/h. For evaluation of the longitudinal loading the regulating braking and motion "by coasting" was considered. For evaluation of buffing loads the entry to the concave gradient change of expanded train is considered, and in order to determine the quasi-static forces the compressed train is considered. Findings. As a result of calculations the dependencies of maximal longitudinal forces in the trains on the cargo type, the algebraic difference of the grades, the number of tank wagons, the initial speed, motion modes, and initial gaps condition in the train were obtained. Originality. The longitudinal loading of freight cars of different length formed by the similar bogie tank wagons with one locomotive was obtained. The locomotive is placed in the train head during motion in concave track sections with various algebraic difference of the grades "on coasting" and during the regulating braking mode. The obtained results can be used for parameters standardization of profile elevation of the track. Practical value. The obtained results show that during operation of tank trains on track sections of complex breakage the most dangerous is regulating braking of preliminary compressed trains during entering on concave parts of track. Level of the greatest buffing and quasi-static longitudinal forces is

Longitudinal links between work experiences and marital satisfaction in african american dual-earner couples.

Science.gov (United States)

Sun, Xiaoran; McHale, Susan M; Crouter, Ann C; Jones, Damon E

2017-12-01

This study assessed associations between both work demands (pressure, hours) and work resources (self-direction) and marital satisfaction in a sample of 164 African American dual-earner couples who were interviewed annually across 3 years. Grounded in the work-home resources and family systems frameworks, results from longitudinal actor-partner interdependence models (APIM) revealed main effects of spouses' work experiences on their own marital satisfaction, but these effects were qualified by the interactive effects of spouses' and partners' work experiences. Some interactive effects were consistent with an amplifying pattern, for example that, beyond the main effects of actor self-direction, marital satisfaction was highest when both spouses experienced high work self-direction. Other effects were consistent with a comparative pattern, such that shorter work hours were linked to lower marital satisfaction only when partners worked longer hours. Gender moderation also was evident in findings that wives' work pressure was negatively linked to marital satisfaction only when their husbands reported high pressure, but husbands' work pressure was negatively linked to marital satisfaction only when their wives reported low pressure. This study advances understanding of work-marriage linkages in African American couples, an understudied group with a distinctive connection to the labor force. Analyses demonstrate what can be learned from investigating the couple as a unit and illustrate how family systems concepts can be addressed via APIM. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Dual source multidetector CT-angiography before transcatheter aortic valve implantation (TAVI) using a high-pitch spiral acquisition mode

Energy Technology Data Exchange (ETDEWEB)

Wuest, W.; Anders, K.; May, M.S.; Uder, M. [University of Erlangen, Department of Radiology, Erlangen (Germany); Schuhbaeck, A.; Gauss, S.; Marwan, M.; Arnold, M.; Muschiol, G.; Daniel, W.G.; Achenbach, S. [University of Erlangen, Department of Cardiology, Erlangen (Germany); Ensminger, S. [University of Erlangen, Department of Cardiac Surgery, Erlangen (Germany)

2012-01-15

Transcatheter Aortic Valve Implantation (TAVI) is an alternative to surgical valve replacement in high risk patients. Angiography of the aortic root, aorta and iliac arteries is required to select suitable candidates, but contrast agents can be harmful due to impaired renal function. We evaluated ECG-triggered high-pitch spiral dual source Computed Tomography (CT) with minimized volume of contrast agent to assess aortic root anatomy and vascular access. 42 patients (82 {+-} 6 years) scheduled for TAVI underwent dual source (DS) CT angiography (CTA) of the aorta using a prospectively ECG-triggered high-pitch spiral mode (pitch = 3.4) with 40 mL iodinated contrast agent. We analyzed aortic root/iliac dimensions, attenuation, contrast to noise ratio (CNR), image noise and radiation exposure. Aortic root/iliac dimensions and distance of coronary ostia from the annulus could be determined in all cases. Mean aortic and iliac artery attenuation was 320 {+-} 70 HU and 340 {+-} 77 HU. Aortic/iliac CNR was 21.7 {+-} 6.8 HU and 14.5 {+-} 5.4 HU using 100 kV (18.8 {+-} 4.1 HU and 8.7 {+-} 2.6 HU using 120 kV). Mean effective dose was 4.5 {+-} 1.2 mSv. High-pitch spiral DSCTA can be used to assess the entire aorta and iliac arteries in TAVI candidates with a low volume of contrast agent while preserving diagnostic image quality. (orig.)

Dual-band reflective polarization converter based on slotted wire resonators

Science.gov (United States)

Li, Fengxia; Zhang, Linbo; Zhou, Peiheng; Chen, Haiyan; Zhao, Rui; Zhou, Yang; Liang, Difei; Lu, Haipeng; Deng, Longjiang

2018-02-01

A dual-band and high-efficiency reflective linear polarization converter composed of a layer of slotted metal wires has been proposed. Both the simulated and experimental results indicate that the structure can convert a linearly polarized wave to its cross-polarized state for two distinct frequency bands under normal incidence: 9.8-15.1 and 19.2-25.7 GHz. This phenomenon is attributed to a resonance that corresponds to the "trapped mode" at 15.8 GHz. This mode is stable with structural parameters and incident angle at a relatively wide range, and thus becomes promising for dual-band (also multiband) devices design. By surface current distribution and electric field analysis, the operation mechanism has been illuminated, especially for the "trapped mode", identified by the equally but also oppositely directed currents in each unit cell.

Strong optical feedback in birefringent dual frequency laser

Institute of Scientific and Technical Information of China (English)

Mao Wei; Zhang Shu-Lian

2006-01-01

Strong optical feedback in a birefringent dual frequency He-Ne laser with a high reflectivity feedback mirror has been investigated for the first time. The output characteristics of two orthogonally polarized modes are demonstrated in two different optical feedback cases: one is for both modes being fed back and the other is for only one of the modes being fed back. Strong mode competition can be observed between the two modes with strong optical feedback. And when one mode's intensity is near its maximum, the other mode is nearly extinguished. When both modes are fed back into the laser cavity, the mode competition is stronger than when only one mode is fed back. The difference in initial intensity between the two orthogonally polarized modes plays an important role in the mode competition, which has been experimentally and theoretically demonstrated.

Dual compression is not an uncommon type of iliac vein compression syndrome.

Science.gov (United States)

Shi, Wan-Yin; Gu, Jian-Ping; Liu, Chang-Jian; Lou, Wen-Sheng; He, Xu

2017-09-01

Typical iliac vein compression syndrome (IVCS) is characterized by compression of left common iliac vein (LCIV) by the overlying right common iliac artery (RCIA). We described an underestimated type of IVCS with dual compression by right and left common iliac arteries (LCIA) simultaneously. Thirty-one patients with IVCS were retrospectively included. All patients received trans-catheter venography and computed tomography (CT) examinations for diagnosing and evaluating IVCS. Late venography and reconstructed CT were used for evaluating the anatomical relationship among LCIV, RCIA and LCIA. Imaging manifestations as well as demographic data were collected and evaluated by two experienced radiologists. Sole and dual compression were found in 32.3% (n = 10) and 67.7% (n = 21) of 31 patients respectively. No statistical differences existed between them in terms of age, gender, LCIV diameter at the maximum compression point, pressure gradient across stenosis, and the percentage of compression level. On CT and venography, sole compression was commonly presented with a longitudinal compression at the orifice of LCIV while dual compression was usually presented as two types: one had a lengthy stenosis along the upper side of LCIV and the other was manifested by a longitudinal compression near to the orifice of external iliac vein. The presence of dual compression seemed significantly correlated with the tortuous LCIA (p = 0.006). Left common iliac vein can be presented by dual compression. This type of compression has typical manifestations on late venography and CT.

Light curing through glass ceramics: effect of curing mode on micromechanical properties of dual-curing resin cements.

Science.gov (United States)

Flury, Simon; Lussi, Adrian; Hickel, Reinhard; Ilie, Nicoleta

2014-04-01

The aim of this study was to investigate micromechanical properties of five dual-curing resin cements after different curing modes including light curing through glass ceramic materials. Vickers hardness (VH) and indentation modulus (Y HU) of Panavia F2.0, RelyX Unicem 2 Automix, SpeedCEM, BisCem, and BeautiCem SA were measured after 1 week of storage (37 °C, 100 % humidity). The resin cements were tested following self-curing or light curing with the second-generation light-emitting diode (LED) curing unit Elipar FreeLight 2 in Standard Mode (1,545 mW/cm(2)) or with the third-generation LED curing unit VALO in High Power Mode (1,869 mW/cm(2)) or in XtraPower Mode (3,505 mW/cm(2)). Light curing was performed directly or through glass ceramic discs of 1.5 or 3 mm thickness of IPS Empress CAD or IPS e.max CAD. VH and Y HU were analysed with Kruskal-Wallis tests followed by pairwise Wilcoxon rank sum tests (α = 0.05). RelyX Unicem 2 Automix resulted in the highest VH and Y HU followed by BeautiCem SA, BisCem, SpeedCEM, and finally Panavia F2.0. Self-curing of RelyX Unicem 2 Automix and SpeedCEM lowered VH and Y HU compared to light curing whereas self-curing of Panavia F2.0, BisCem, and BeautiCem SA led to similar or significantly higher VH and Y HU compared to light curing. Generally, direct light curing resulted in similar or lower VH and Y HU compared to light curing through 1.5-mm-thick ceramic discs. Light curing through 3-mm-thick discs of IPS e.max CAD generally reduced VH and Y HU for all resin cements except SpeedCEM, which was the least affected by light curing through ceramic discs. The resin cements responded heterogeneously to changes in curing mode. The applied irradiances and light curing times adequately cured the resin cements even through 1.5-mm-thick ceramic discs. When light curing resin cements through thick glass ceramic restorations, clinicians should consider to prolong the light curing times even with LED curing units providing high

Mode group specific amplification length in an asymmetric LPG assisted few-mode EDFA

Science.gov (United States)

Rastogi, Vipul; Gaur, Ankita; Aschieri, Pierre; Dussardier, Bernard

2017-01-01

This article presents a scheme for few-mode EDFA, which allows to choose independent amplification lengths for different mode groups. The EDF is a dual concentric core fiber, where the central core is connected to the line FMF and the ring core is doped with erbium to provide amplification. The modes of FMF are launched into the central core of the EDF, are converted into ring modes using LPG for amplification and then converted back into central core modes using another LPG. The distance between the LPGs determines the amplification length. The amplification length, can thus, be chosen for a given mode group. We demonstrate the working of this concept by choosing LP11 and LP21 mode groups of the FMF and show that a suitable choice of amplification lengths for the two mode groups can tailor the differential modal gain (DMG) to any desired value. We demonstrate achieving zero DMG among all the mode of LP11 and LP21 mode groups using this concept while having gain in excess of 20 dB. The study should be useful for optical fiber communication system employing space-division multiplexing (SDM).

Dual Mode Offering As Viable Approach 
For Promotion Of Higher Education In Pakistan

Directory of Open Access Journals (Sweden)

Irshad HUSSAIN

2014-01-01

Full Text Available Pakistan is a developing with 148 universities and degree awarding institutions including public and private sector. The enrolment as given in the National Educational Policy 2009 was up to 5% only. It reflects greater demands of higher/tertiary education and calls for alternative strategic measures for addressing the issue. An innovative approach was necessary to address the issue of access. Therefore, the Islamia University of Bahawalpur –a formal mode university took an innovative initiative to become a dual mode university by establishing an Institute of Distance Education (IDE in 2011. The institute offered along with others, an M.Phill programme in ten disciplines through distance education mode in semester fall 2011. More than eight hundred applications were received by potential learners against 275 seats. However, after test and interview 189 students were enrolled in M.Phill programme in Applied Psychology, Arabic, Education, English, Media Studies, Islamic Studies, Pakistan Studies, History, Persian, and Urdu. In the beginning, the Institute organized an orientation workshop for learners to guide them studying in distance education system. The programme was offered under semester system and the semester was broke up into two halves –mid-term and final term. The respective departments provided learning materials to students whereas the IDE provided instructional booklet. Submission of two assignments was compulsory for the entire semester; one before mid-term and second before final-term workshop/ examination for each of the courses. Similarly, students’ presence in workshops for 24 hours (12 during mid-term and 12 during final-term workshop for one 3-credit hour course was mandatory. Students’ support services were provided through Skype conference, social media and mobile phones. Students necessarily had to give presentations and submit their assignments after checking their similarity index by using turnitin software. At the

Comparison of endothelial changes and power settings between torsional and longitudinal phacoemulsification.

Science.gov (United States)

Reuschel, Anna; Bogatsch, Holger; Barth, Thomas; Wiedemann, Renate

2010-11-01

To compare the intraoperative and postoperative outcomes of conventional longitudinal phacoemulsification and torsional phacoemulsification. Department of Ophthalmology, University of Leipzig, Germany. Randomized single-center clinical trial. Eyes with senile cataract were randomized to have phacoemulsification using the Infiniti Vision System and the torsional mode (OZil) or conventional longitudinal mode. Primary outcomes were corrected distance visual acuity (CDVA) and central endothelial cell density (ECD), calculated according to the Conference on Harmonisation-E9 Guidelines in which missing values were substituted by the median in each group (primary analysis) and the loss was then calculated using actual data (secondary analysis). Secondary outcomes were ultrasound (US) time, cumulative dissipated energy (CDE), and percentage total equivalent power in position 3. Postoperative follow-up was at 3 months. The mean preoperative CDVA was 0.41 logMAR in the torsional group and 0.38 logMAR in the longitudinal group, improving to 0.07 logMAR postoperatively in both groups. The mean ECD loss was 7.2% ± 4.6% in the torsional group (72 patients) and 7.1% ± 4.4% in the longitudinal group (76 patients), with no statistically significant differences in the primary analysis (P = .342) or secondary analysis (P = .906). The mean US time, CDE, and percentage total equivalent power in position 3 were statistically significantly lower in the torsional group (98 patients) than in the longitudinal group (94 patients) (P<.001). The torsional mode was as safe as the longitudinal mode in phacoemulsification for age-related cataract. Copyright © 2010 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Bunched beam longitudinal stability

International Nuclear Information System (INIS)

Baartman, R.

1991-05-01

Instabilities driven by narrow-band impedances can be stabilized by Landau damping arising from the synchrotron frequency spread due to the nonlinearity of the rf wave-form. We calculate stability diagrams for various phase space distributions. We find that distributions without tails are unstable in the 'negative mass' regime (inductive impedance below transition or capacitive impedance above transition). We also find that longitudinal instability thresholds of the (usually neglected) higher order radial modes are lower than expected. For example, the next to lowest dipole mode has a lower threshold than the lowest sextupole mode even though the latter has the larger growth rate in the absence of Landau damping. (Author) 5 refs., 5 figs

When dual identity becomes a liability: identity and political radicalism among migrants.

Science.gov (United States)

Simon, Bernd; Reichert, Frank; Grabow, Olga

2013-03-01

This article examines the role of dual identity in political radicalism among migrants. Dual identity is defined as identification with both one's ethnocultural minority in-group and one's society of residence. We employed a longitudinal research design using members of the two largest migrant groups in Germany (Turkish migrants and Russian migrants) as participants. We reasoned that when dual identity is burdened with incompatibility between component identifications, it may foster controversial or even destructive forms of political mobilization, such as radicalism. Multiple regression analysis controlling for other influences confirmed the hypothesized moderated relationship between dual identification and sympathy for radical action. When accompanied by high, as opposed to low, perceived identity incompatibility, dual identification predicted increases in sympathy for radical action among both Turkish migrants and Russian migrants. The implications for public life in ethnically and culturally heterogeneous societies are discussed.

Longitudinal body composition of children born to mothers with normal weight, overweight, and obesity.

Science.gov (United States)

Andres, Aline; Hull, Holly R; Shankar, Kartik; Casey, Patrick H; Cleves, Mario A; Badger, Thomas M

2015-06-01

The longitudinal trajectories of body composition of children born to mothers with normal weight, overweight, and obesity have not been evaluated using precise body composition methods. This study investigated the relationship between maternal prepregnancy BMI and offspring body composition trajectories during the first 6 years of life. Healthy infants (N = 325) were assessed longitudinally (at ages 0.25, 0.5, 0.75, 1, 2, 3, 4, 5, and 6 years) using dual-energy X-ray absorptiometry. Mixed-effects regression for repeated measures was used to model each continuous outcome as a function of maternal BMI and covariates (race, gestational age, birth weight, and mode of infant feeding). Maternal obesity differentially impacted body fat, but not bone mineral content or density, of girls and boys. Boys born to mothers with obesity have higher body fat from ages 2-6 years compared to boys born to normal-weight and overweight mothers (P obesity was not different across groups during the first 6 years of life (P > 0.05). This clinical observational study demonstrates a sexual dimorphism in offspring body composition until age 6 years based on maternal BMI, with a greater effect of maternal adiposity seen in boys than in girls. © 2015 The Obesity Society.

Short-term precision assessment of trabecular bone score and bone mineral density using dual-energy X-ray absorptiometry with different scan modes: an in vivo study

Energy Technology Data Exchange (ETDEWEB)

Bandirali, Michele; Poloni, Alessandro; Messina, Carmelo; Petrini, Marcello [Universita degli Studi di Milano, Scuola di Specializzazione in Radiodiagnostica, Milano (Italy); Sconfienza, Luca Maria; Sardanelli, Francesco [Unita di Radiologia, IRCCS Policlinico San Donato, San Donato Milanese (Italy); Universita degli Studi di Milano, Dipartimento di Scienze Biomediche per la Salute, San Donato Milanese (Italy); Papini, Giacomo Davide Edoardo; Di Leo, Giovanni [Unita di Radiologia, IRCCS Policlinico San Donato, San Donato Milanese (Italy); Ulivieri, Fabio Massimo [IRCCS Fondazione Ca' Granda Ospedale Maggiore Policlinico, Mineralometria Ossea Computerizzata e Ambulatorio Malattie Metabolismo Minerale e Osseo, Servizio di Medicina Nucleare, Milano (Italy)

2015-07-15

We estimated the in vivo reproducibility of trabecular bone score (TBS) from dual-energy X-ray absorptiometry (DXA) using different imaging modes to be compared to that of bone mineral density (BMD). We enrolled 30 patients for each imaging mode: fast-array, array, high definition. Each patient underwent two DXA examinations with in-between repositioning. BMD and TBS were obtained according to the International Society for Clinical Densitometry guidelines. The coefficient of variation (CoV) was calculated as the ratio between root mean square standard deviation and mean, percent least significant change (LSC) as 2.77 x CoV, reproducibility as the complement to 100 % LSC. Fast-array imaging mode resulted in 0.8 % CoV and 2.1 % LSC for BMD, 1.9 % and 5.3 % for TBS, respectively; array imaging mode resulted in 0.7 % and 2.0 % for BMD, 1.9 % and 5.2 %, for TBS; high-definition imaging mode resulted in 0.7 % and 2.0 %, for BMD; 2.0 % and 5.4 % for TBS, respectively. Reproducibility of TBS (95 %) was significantly lower than that of BMD (98 %) (p < 0.012). Difference in reproducibility among the imaging modes was not significant for either BMD or TBS (p = 0.942). While TBS reproducibility was significantly lower than that of BMD, differences among imaging modes were not significant for both TBS and BMD. (orig.)

S-dual inflation: BICEP2 data without unlikeliness

International Nuclear Information System (INIS)

Anchordoqui, Luis A.; Barger, Vernon; Goldberg, Haim; Huang, Xing; Marfatia, Danny

2014-01-01

We show that S-dual inflationary potentials solve the unlikeliness problem manifested in Planck data and explain the excess B-mode power observed by the BICEP2 experiment as arising from primordial tensor fluctuations

Experimental evaluation of a diesel-biogas dual fuel engine operated on micro-trigeneration system for power, drying and cooling

International Nuclear Information System (INIS)

Cacua, Karen; Olmos-Villalba, Luis; Herrera, Bernardo; Gallego, Anderson

2016-01-01

Highlights: • A micro-trigeneration system based in a diesel-biogas dual fuel engine was obtained. • Heat from engine exhaust gases was used for drying and refrigeration applications. • Energy efficiency of the microtrigeneration system in dual mode was 40%. • Peppermint was dried in the microtrigeneration system. - Abstract: A micro-trigeneration system based on a diesel-biogas dual fuel engine was evaluated experimentally. In this system, waste heat from the engine exhaust was used for heating air using a heat pipe exchanger and for driving an absorption unit freezer. The air heated was used in a convective trays dryer designed to dry peppermint. The global energy efficiency of this system at the engine full load was 40% and 31% in diesel and dual mode, respectively, while the same efficiencies of the engine at the original single generation were 23% and 18%, respectively. On the other hand, a maximum diesel substitution level of 50% was achieved in dual mode.

Computer code and users' guide for the preliminary analysis of dual-mode space nuclear fission solid core power and propulsion systems, NUROC3A. AMS report No. 1239b

Energy Technology Data Exchange (ETDEWEB)

Nichols, R.A.; Smith, W.W.

1976-06-30

The three-volume report describes a dual-mode nuclear space power and propulsion system concept that employs an advanced solid-core nuclear fission reactor coupled via heat pipes to one of several electric power conversion systems. The second volume describes the computer code and users' guide for the preliminary analysis of the system.

A dual-band reconfigurable Yagi-Uda antenna with diverse radiation patterns

Science.gov (United States)

Saurav, Kushmanda; Sarkar, Debdeep; Srivastava, Kumar Vaibhav

2017-07-01

In this paper, a dual-band pattern reconfigurable antenna is proposed. The antenna comprises of a dual-band complementary split ring resonators (CSRRs) loaded dipole as the driven element and two copper strips with varying lengths as parasitic segments on both sides of the driven dipole. PIN diodes are used with the parasitic elements to control their electrical length. The CSRRs loading provide a lower order mode in addition to the reference dipole mode, while the parasitic elements along with the PIN diodes are capable of switching the omni-directional radiation of the dual-band driven element to nine different configurations of radiation patterns which include bi-directional end-fire, broadside, and uni-directional end-fire in both the operating bands. A prototype of the designed antenna together with the PIN diodes and DC bias lines is fabricated to validate the concept of dual-band radiation pattern diversity. The simulation and measurement results are in good agreement. The proposed antenna can be used in wireless access points for PCS and WLAN applications.

Coupled mode theory of periodic waveguides arrays

DEFF Research Database (Denmark)

Lavrinenko, Andrei; Chigrin, Dmitry N.

We apply the scalar coupled mode theory to the case of waveguides array consisting om two periodic waveguides. One of the waveguides is arbitrary shifted along another. A longitudinal shift acts as a parameter in the coupled mode theory. The proposed theory explains peculiarities of modes dispers...... dispersion and transmission in coupled periodic waveguides systems. Analytical results are compared with the numerical ones obtained by the plane wave expansion and FDTD methods....

Attenuation process of the longitudinal phonon mode in a TeO2 crystal in the 20-GHz range

Science.gov (United States)

Ohno, S.; Sonehara, T.; Tatsu, E.; Koreeda, A.; Saikan, S.

2017-06-01

We experimentally investigated the hypersonic attenuation process of a longitudinal mode (L-mode) sound wave in TeO2 from room temperature to a lower temperature using Brillouin scattering and impulsive stimulated thermal scattering (ISTS) measurements. For precise measurement of the Brillouin linewidth at low temperatures, whereby the mean free path of the phonon becomes longer than the sample length, it is indispensable that the phonon should propagate along the phonon-resonance direction. To figure out the suitable direction, we defined two indices characterizing a degree of phonon divergence and a purity of propagation direction. The best direction that we found from these indices is [110] direction in TeO2, and it was used to discuss the temperature and frequency dependences of Brillouin spectra. We extracted the temperature dependence of the attenuation rate of T4 from the modulated Brillouin spectra due to the phonon resonance below Debye temperature. The frequency dependence ω1 of the hypersonic attenuation was also estimated from the polarization dependence of the Brillouin linewidth. Theoretically, it predicted that the L-mode phonon attenuation at low temperatures in TeO2 is a result of Herring's process, which shows the attenuation behavior of ω2T3 . The ω1T4 dependence is not allowed in Herring's process but is allowed by the L +L →L process, which has been considered to be forbidden so far. We evaluated the thermal phonon lifetime using ISTS and established that it was finite even at 20 K, thereby allowing the L +L →L process. Therefore, we conclude that the L +L →L process dominates the attenuation of an L-mode phonon in TeO2 in the low-temperature region.

Picometer-resolution dual-comb spectroscopy with a free-running fiber laser.

Science.gov (United States)

Zhao, Xin; Hu, Guoqing; Zhao, Bofeng; Li, Cui; Pan, Yingling; Liu, Ya; Yasui, Takeshi; Zheng, Zheng

2016-09-19

Dual-comb spectroscopy holds the promise as real-time, high-resolution spectroscopy tools. However, in its conventional schemes, the stringent requirement on the coherence between two lasers requires sophisticated control systems. By replacing control electronics with an all-optical dual-comb lasing scheme, a simplified dual-comb spectroscopy scheme is demonstrated using one dual-wavelength, passively mode-locked fiber laser. Pulses with a intracavity-dispersion-determined repetition-frequency difference are shown to have good mutual coherence and stability. Capability to resolve the comb teeth and a picometer-wide optical spectral resolution are demonstrated using a simple data acquisition system. Energy-efficient, free-running fiber lasers with a small comb-tooth-spacing could enable low-cost dual-comb systems.

Note: Pulsed single longitudinal mode optical parametric oscillator for sub-Doppler spectroscopy of jet cooled transient species

Science.gov (United States)

Zhang, Qiang; Zhu, Boxing; Zhang, Deping; Gu, Jingwang; Zhao, Dongfeng; Chen, Yang

2017-12-01

We present a pulsed single longitudinal mode optical parametric oscillator that was recently constructed for sub-Doppler spectroscopic studies of transient species in a supersonic slit jet expansion environment. The system consists of a Littman-type grazing-incidence-grating resonator and a KTP crystal and is pumped at 532 nm. By spatially filtering the pump laser beam and employing an active cavity-length-stabilization scheme, a frequency down-conversion efficiency up to 18% and generation of Fourier-transform limited pulses with a typical pulse duration of ˜5.5 ns and a bandwidth less than 120 MHz have been achieved. In combination with a slit jet expansion, a sub-Doppler spectrum of SiC2 has been recorded at ˜498 nm, showing a spectral resolution of Δν/ν ≈ 6.2 × 10-7.

Interacting-string picture of dual-resonance models

International Nuclear Information System (INIS)

Mandelstam, S.

1985-01-01

Dual-resonance models are an alyzed by means of operators which act within the physical Hilbert space of positive-metric states. The basis of the method is to extend the relativistic-string picture of a previous study to interacting particles. Functional methods are used, but their relation to the operator is evident, and factorization is maintained. An expression is given for the N-point amplitude in terms of physical-particle operators. For the three-point function the Neumann functions which occur in this expression are evaluated, so that we have a formula for the on- and off-energy-shell vertex. The authors assume that the string has no longitudinal degrees of freedom, and their results are Lorentz invariant and dual only if d=26

Development of an Advanced Digital Reactor Protection System Using Diverse Dual Processors to Prevent Common-Mode Failure

International Nuclear Information System (INIS)

Shin, Hyun Kook; Nam, Sang Ku; Sohn, Se Do; Chang, Hoon Seon

2003-01-01

The advanced digital reactor protection system (ADRPS) with diverse dual processors has been developed to prevent common-mode failure (CMF). The principle of diversity is applied to both hardware design and software design. For hardware diversity, two different types of CPUs are used for the bistable processor and local coincidence logic (LCL) processor. The Versa Module Eurocard-based single board computers are used for the CPU hardware platforms. The QNX operating system and the VxWorks operating system were selected for software diversity. Functional diversity is also applied to the input and output modules, and to the algorithm in the bistable processors and LCL processors. The characteristics of the newly developed digital protection system are described together with the preventive capability against CMF. Also, system reliability analysis is discussed. The evaluation results show that the ADRPS has a good preventive capability against the CMF and is a highly reliable reactor protection system

Evaluación energética de un sistema de generación de 400 kWe en modo diesel‐gas licuado de petróleo//Energy analysis of a 400 kWe power system operated on dual fuel mode with diesel‐liquefied petroleum gas

Directory of Open Access Journals (Sweden)

Carlos‐A. Forero-Núñez

2014-08-01

Full Text Available El constante aumento en los precios de los combustibles impulsó el desarrollo de sistemas energéticos cada vez más eficientes y flexibles, los cuales permitan el uso de distintos tipos de combustibles, tales como el gas licuado de petróleo (GLP. El presente trabajo buscó analizar el comportamiento energético y ambiental que tiene una planta de generación de 400 kWe operada en modo diesel y dual diesel-GLP de pozo. La eficiencia energética total del sistema en el punto de máxima carga fue igual a 39,9 % en modo diesel y 35,1 % con una relación de sustitución del 28,5 % en modo dual. La adición de GLP resultó en una disminución del índice de emisiones de CO2 de 0,76 a 0,71 kgkWh-1. El adecuado comportamiento del sistema genera interesantes oportunidades para la disminución del impacto ambiental causado por los sistemas diesel, la diversificación de la canasta energética y la reducción de costos de generación eléctrica en pozos petroleros.Palabras claves: eficiencia energética, diesel, GLP, modo dual.________________________________________________________________________________AbstractThe continuous increase of the fuel costs promoted the development of more efficient and flexible power systems, which could use alternative fuels such as liquefied petroleum gas (LPG. This work aimed to analyze the performance and environmental effect of a 400kWe power system fed with diesel and diesel-LGP on a dual fuel mode. The total electric efficiency of this system at his maximum load was 39,9 % with diesel and 35,1 % at a 28,5 % substitution level on a dual fuel mode. The addition of LPG decreased the CO2 emission index from 0,76 to 0,71 kgkWh-1. The proper behavior of this system on a dual fuel mode mitigated the environmental impact of diesel internal combustion engines, diversified the energy market, and reduced the power generation costs onto petroleum extraction wells.Key words: energy efficiency, diesel, LPG, dual fuel mode.

Equilibrium calculations and mode analysis

International Nuclear Information System (INIS)

Herrnegger, F.

1987-01-01

The STEP asymptotic stellarator expansion procedure was used to study the MHD equilibrium and stability properties of stellarator configurations without longitudinal net-current, which also apply to advanced stellarators. The effects of toroidal curvature and magnetic well, and the Shafranov shift were investigated. A classification of unstable modes in toroidal stellarators is given. For WVII-A coil-field configurations having a β value of 1% and a parabolic pressure profile, no free-boundary modes are found. This agrees with the experimental fact that unstable behavior of the plasma column is not observed for this parameter range. So a theoretical β-limit for stability against ideal MHD modes can be estimated by mode analysis for the WVII-A device

Dual mode emission and harmonic generation in ZnO-CaO-Al{sub 2}O{sub 3}: Er{sup 3+} nano-composite

Energy Technology Data Exchange (ETDEWEB)

Verma, R.K. [Laser and Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221005 (India); Kumar, K. [Laser and Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221005 (India); Nano-technology Application Centre, University of Allahabad, Allahabad (India); Rai, S.B., E-mail: sbrai49@yahoo.co.i [Laser and Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221005 (India)

2011-05-15

Er{sup 3+} doped ZnO-CaO-Al{sub 2}O{sub 3} nano-composite phosphor has been synthesized through combustion method and its emission and harmonic generation properties have been studied. The X-ray diffraction and thermal analysis techniques have been used to prove the dual phase (ZnO and CaO-Al{sub 2}O{sub 3}) nature of the phosphor. The phosphor has shown up-conversion emission on near-infra-red (976 nm) excitation and down-conversion emission on 355 nm excitation in presence of Er{sup 3+} and thus behaves as a dual mode phosphor. On excitation with 976 nm diode laser, material shows color tunability (calcination of composite material at different temperatures). Formation of ZnO nanocrystals on heat treatment of as-synthesized sample has shown its characteristic emission at 388 nm and also the energy transfer from ZnO to Er{sup 3+} ions. The low temperature emission measurements have been carried out and the results have been discussed. Phosphor has shown strong second harmonic generation (SHG) at 532 nm on 1064 nm and at 266 nm on 532 nm excitation. - Research highlights: {yields} We have synthesized Er{sup 3+} doped composite material by combustion method. The two phases of composites are ZnO and CaO-Al{sub 2}O{sub 3}. {yields} The phosphor has shown up-conversion emission on near-infra-red (976 nm) excitation and down-conversion emission on 355 nm excitation in presence of Er{sup 3+} and thus behaves as a dual mode phosphor. This material also shows colour tenability on excitation of 976 nm diode laser at different temperature calcinations (i.e., As-synthesized to calcinated at 1473 K). {yields} Low temperature effects on Er{sup 3+} as well as ZnO emission have been carried out. We observed that at low temperature the efficiency of Er{sup 3+} increases while in the case of ZnO its intensity increases and also 12 nm shifting observed. {yields} Composite material has shown strong second harmonic generation (SHG) at 532 nm on 1064 nm and at 266 nm on 532 nm

Operation of PEP longitudinal feedback system

International Nuclear Information System (INIS)

Allen, M.A.; Karvonen, L.G.; McConnell, R.A.; Schwarz, H.

1981-03-01

In order to suppress longitudinal coupled-bunch oscillations which might limit the capabilities of PEP, the 18 GeV e + e - storage ring at SLAC, a longitudinal feedback system is utilized. A frequency domain feedback system was chosen with the frequency spectrum of the stored beam being sampled close to a symmetry point in the ring where the feedback cavity itself is also located. The symmetry point chosen is symmetry point 5 which lies half-way between interaction regions 4 and 6. The system has been installed in PEP and is now operational. However, at stored currents up to the maximum stored in PEP to date at 14.5 GeV (approximately 40 mA in 6 bunches), the ring has been stable to all modes of longitudinal coupled-bunch oscillations both barycentric and the other fundamental modes. By deliberately detuning the main accelerating cavities, small multibunch oscillations can be introduced which, in turn, can be damped by the feedback system. Under optimized beam conditions the feedback system could be adjusted to positive feedback and excite oscillations with relatively small power to the feedback cavity. This will be described along with other details of the system

A Noise Reduction Method for Dual-Mass Micro-Electromechanical Gyroscopes Based on Sample Entropy Empirical Mode Decomposition and Time-Frequency Peak Filtering.

Science.gov (United States)

Shen, Chong; Li, Jie; Zhang, Xiaoming; Shi, Yunbo; Tang, Jun; Cao, Huiliang; Liu, Jun

2016-05-31

The different noise components in a dual-mass micro-electromechanical system (MEMS) gyroscope structure is analyzed in this paper, including mechanical-thermal noise (MTN), electronic-thermal noise (ETN), flicker noise (FN) and Coriolis signal in-phase noise (IPN). The structure equivalent electronic model is established, and an improved white Gaussian noise reduction method for dual-mass MEMS gyroscopes is proposed which is based on sample entropy empirical mode decomposition (SEEMD) and time-frequency peak filtering (TFPF). There is a contradiction in TFPS, i.e., selecting a short window length may lead to good preservation of signal amplitude but bad random noise reduction, whereas selecting a long window length may lead to serious attenuation of the signal amplitude but effective random noise reduction. In order to achieve a good tradeoff between valid signal amplitude preservation and random noise reduction, SEEMD is adopted to improve TFPF. Firstly, the original signal is decomposed into intrinsic mode functions (IMFs) by EMD, and the SE of each IMF is calculated in order to classify the numerous IMFs into three different components; then short window TFPF is employed for low frequency component of IMFs, and long window TFPF is employed for high frequency component of IMFs, and the noise component of IMFs is wiped off directly; at last the final signal is obtained after reconstruction. Rotation experimental and temperature experimental are carried out to verify the proposed SEEMD-TFPF algorithm, the verification and comparison results show that the de-noising performance of SEEMD-TFPF is better than that achievable with the traditional wavelet, Kalman filter and fixed window length TFPF methods.

A Noise Reduction Method for Dual-Mass Micro-Electromechanical Gyroscopes Based on Sample Entropy Empirical Mode Decomposition and Time-Frequency Peak Filtering

Directory of Open Access Journals (Sweden)

Chong Shen

2016-05-01

Full Text Available The different noise components in a dual-mass micro-electromechanical system (MEMS gyroscope structure is analyzed in this paper, including mechanical-thermal noise (MTN, electronic-thermal noise (ETN, flicker noise (FN and Coriolis signal in-phase noise (IPN. The structure equivalent electronic model is established, and an improved white Gaussian noise reduction method for dual-mass MEMS gyroscopes is proposed which is based on sample entropy empirical mode decomposition (SEEMD and time-frequency peak filtering (TFPF. There is a contradiction in TFPS, i.e., selecting a short window length may lead to good preservation of signal amplitude but bad random noise reduction, whereas selecting a long window length may lead to serious attenuation of the signal amplitude but effective random noise reduction. In order to achieve a good tradeoff between valid signal amplitude preservation and random noise reduction, SEEMD is adopted to improve TFPF. Firstly, the original signal is decomposed into intrinsic mode functions (IMFs by EMD, and the SE of each IMF is calculated in order to classify the numerous IMFs into three different components; then short window TFPF is employed for low frequency component of IMFs, and long window TFPF is employed for high frequency component of IMFs, and the noise component of IMFs is wiped off directly; at last the final signal is obtained after reconstruction. Rotation experimental and temperature experimental are carried out to verify the proposed SEEMD-TFPF algorithm, the verification and comparison results show that the de-noising performance of SEEMD-TFPF is better than that achievable with the traditional wavelet, Kalman filter and fixed window length TFPF methods.

Experimental and theoretical analysis of the combustion process at low loads of a diesel natural gas dual-fuel engine

International Nuclear Information System (INIS)

Li, Weifeng; Liu, Zhongchang; Wang, Zhongshu

2016-01-01

To construct an effective method to analyze the combustion process of dual fuel engines at low loads, effects of combustion boundaries on the combustion process of an electronically controlled diesel natural gas dual-fuel engine at low loads were investigated. Three typical combustion modes, including h, m and n, appeared under different combustion boundaries. In addition, the time-sequenced characteristic and the heat release rate-imbalanced characteristic were found in the dual fuel engine combustion process. To quantify these characteristics, two quantitative indicators, including the TSC (time-sequenced coefficient) and the HBC (HRR-balanced coefficient) were defined. The results show that increasing TSC and HBC can decrease HC (hydrocarbon) emissions and improve the BTE (brake thermal efficiency) significantly. The engine with the n combustion mode can obtain the highest BTE and the lowest HC emissions, followed by m, and then h. However, the combustion process of the engine will deteriorate sharply if boundary conditions are not strictly controlled in the n combustion mode. Based on the n combustion mode, advancing the start of diesel injection significantly, using large EGR (exhaust gas recirculation) rate and appropriately intake throttling can effectively reduce HC emissions and improve the BTE of dual fuel engines at low loads with relatively high natural gas PES (percentage energy substitution). - Highlights: • We reported three typical combustion modes of a dual-fuel engine at low loads. • Time-sequenced characteristic was put forward and qualified. • HRR-imbalanced characteristic was put forward and qualified. • Three combustion modes appeared as equivalence ratio/diesel injection timing varied. • The engine performance varied significantly with different combustion mode.

A longitudinal study on dual-tasking effects on gait: cognitive change predicts gait variance in the elderly.

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Rebecca K MacAulay

Full Text Available Neuropsychological abilities have found to explain a large proportion of variance in objective measures of walking gait that predict both dementia and falling within the elderly. However, to this date there has been little research on the interplay between changes in these neuropsychological processes and walking gait overtime. To our knowledge, the present study is the first to investigate intra-individual changes in neurocognitive test performance and gait step time at two-time points across a one-year span. Neuropsychological test scores from 440 elderly individuals deemed cognitively normal at Year One were analyzed via repeated measures t-tests to assess for decline in cognitive performance at Year Two. 34 of these 440 individuals neuropsychological test performance significantly declined at Year Two; whereas the "non-decliners" displayed improved memory, working memory, attention/processing speed test performance. Neuropsychological test scores were also submitted to factor analysis at both time points for data reduction purposes and to assess the factor stability overtime. Results at Year One yielded a three-factor solution: Language/Memory, Executive Attention/Processing Speed, and Working Memory. Year Two's test scores also generated a three-factor solution (Working Memory, Language/Executive Attention/Processing Speed, and Memory. Notably, language measures loaded on Executive Attention/Processing Speed rather than on the Memory factor at Year Two. Hierarchal multiple regression revealed that both Executive Attention/Processing Speed and sex significantly predicted variance in dual task step time at both time points. Remarkably, in the "decliners", the magnitude of the contribution of the neuropsychological characteristics to gait variance significantly increased at Year Two. In summary, this study provides longitudinal evidence of the dynamic relationship between intra-individual cognitive change and its influence on dual task gait

Effect of curing mode on the hardness of dual-cured composite resin core build-up materials

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César Augusto Galvão Arrais

2010-06-01

Full Text Available This study evaluated the Knoop Hardness (KHN values of two dual-cured composite resin core build-up materials and one resin cement exposed to different curing conditions. Two dual-cured core build-up composite resins (LuxaCore®-Dual, DMG; and FluoroCore®2, Dentsply Caulk, and one dual-cured resin cement (Rely X ARC, 3M ESPE were used in the present study. The composite materials were placed into a cylindrical matrix (2 mm in height and 3 mm in diameter, and the specimens thus produced were either light-activated for 40 s (Optilux 501, Demetron Kerr or were allowed to self-cure for 10 min in the dark (n = 5. All specimens were then stored in humidity at 37°C for 24 h in the dark and were subjected to KHN analysis. The results were submitted to 2-way ANOVA and Tukey's post-hoc test at a pre-set alpha of 5%. All the light-activated groups exhibited higher KHN values than the self-cured ones (p = 0.00001, regardless of product. Among the self-cured groups, both composite resin core build-up materials showed higher KHN values than the dual-cured resin cement (p = 0.00001. LuxaCore®-Dual exhibited higher KHN values than FluoroCore®2 (p = 0.00001 when they were allowed to self-cure, while no significant differences in KHN values were observed among the light-activated products. The results suggest that dual-cured composite resin core build-up materials may be more reliable than dual-cured resin cements when curing light is not available.

Automatically sweeping dual-channel boxcar integrator

International Nuclear Information System (INIS)

Keefe, D.J.; Patterson, D.R.

1978-01-01

An automatically sweeping dual-channel boxcar integrator has been developed to automate the search for a signal that repeatedly follows a trigger pulse by a constant or slowly varying time delay when that signal is completely hidden in random electrical noise and dc-offset drifts. The automatically sweeping dual-channel boxcar integrator improves the signal-to-noise ratio and eliminates dc-drift errors in the same way that a conventional dual-channel boxcar integrator does, but, in addition, automatically locates the hidden signal. When the signal is found, its time delay is displayed with 100-ns resolution, and its peak value is automatically measured and displayed. This relieves the operator of the tedious, time-consuming, and error-prone search for the signal whenever the time delay changes. The automatically sweeping boxcar integrator can also be used as a conventional dual-channel boxcar integrator. In either mode, it can repeatedly integrate a signal up to 990 times and thus make accurate measurements of the signal pulse height in the presence of random noise, dc offsets, and unsynchronized interfering signals

Source book for planning nuclear dual-purpose electric/distillation desalination plants

International Nuclear Information System (INIS)

Reed, S.A.

1981-02-01

A source book on nuclear dual-purpose electric/distillation desalination plants was prepared to assist government and other planners in preparing broad evaluations of proposed applications of dual-purpose plants. The document is divided into five major sections. Section 1 presents general discussions relating to the benefits of dual-purpose plants, and spectrum for water-to-power ratios. Section 2 presents information on commercial nuclear plants manufactured by US manufacturers. Section 3 gives information on distillation desalting processes and equipment. Section 4 presents a discussion on feedwater pretreatment and scale control. Section 5 deals with methods for coupling the distillation and electrical generating plants to operate in the dual mode

Source book for planning nuclear dual-purpose electric/distillation desalination plants

Energy Technology Data Exchange (ETDEWEB)

Reed, S.A.

1981-02-01

A source book on nuclear dual-purpose electric/distillation desalination plants was prepared to assist government and other planners in preparing broad evaluations of proposed applications of dual-purpose plants. The document is divided into five major sections. Section 1 presents general discussions relating to the benefits of dual-purpose plants, and spectrum for water-to-power ratios. Section 2 presents information on commercial nuclear plants manufactured by US manufacturers. Section 3 gives information on distillation desalting processes and equipment. Section 4 presents a discussion on feedwater pretreatment and scale control. Section 5 deals with methods for coupling the distillation and electrical generating plants to operate in the dual mode.

The diagnostic value of dual energy virtual non-contrast images of dual-source CT in the diagnosis of com-mon benign liver diseases%双源CT双能量虚拟平扫对肝脏常见良性病变的诊断价值

Institute of Scientific and Technical Information of China (English)

刘盼; 王凤; 李邦国; 罗显丽; 王梦; 王荣品

2017-01-01

Objective To investigate the diagnostic value and limitations of dual-energy virtual non-con-trast images of dual-source CT in common benign liver diseases. Methods Dual-source CT was performed on 226 upper abdomen pathogenesis patients. The conventional non-contrast (CNC) scan was performed with single-energy mode, the arterial phase and portal phase scans were performed with dual-energy mode. The virtual non-contrast (VNC) images were derived from the portal data using liver virtual non-contrast software. 117 patients with common benign liver diseases were retrospectively analyzed in CNC and VNC. The lesion detectability, effective radiation doses for single-energy mode and dual-energy mode were compared. Results Among 117 patients, there were 28 (73.6%) hemangiomas, 58 (85.3%) calcifications or stones in VNC, but the hemangiomas, calcifications or stones in CNC were 37 (97.3%) and 68 (100%), respectively. The hemangiomas, calcifications or stones in VNC and CNC were significantly different (P 0.05). The CTDIvol, DLP and ED of dual-energy mode were obviously lower than those of single-energy mode (P 0.05);双能模式下CTDI、DLP及ED均低于单能模式,差异有统计学意义(P<0.05).结论:虚拟平扫对血管瘤、钙化或结石的检出低于常规平扫,对囊肿及脂肪肝的检出无差异.VNC技术可减低CT检查的辐射剂量,具有潜在的临床应用价值.

In vitro differentiation of renal stone composition using dual-source, dual-energy CT

International Nuclear Information System (INIS)

Zhou Changsheng; Zhang Longjiang; Xu Feng; Qi Li; Zhao Yan'e; Zheng Ling; Huang Wei; Liu Youhuang; Lu Guangming

2012-01-01

Objective: To evaluate the ability of dual-source. dual-energy CT in differentiating uric acid stones from non-uric acid stones with infrared spectroscopy as reference standard. Materials and Methods: Urinary calculus from 308 patients were scanned in first generation dual-source CT with dual-energy mode between July 2011 and June 2012. Renal Stone application was used to analyze their composition. The uric acid stones color were coded red and non-uric acid stones were blue. CT values were measured in 60 selective urinary calculus including 30 uric acid stones and 30 non-uric acid stones. The accuracy of dual energy CT to differentiate uric acid and no-uric acid stones was calculated. Results: Of 308 patients, 60 patients had uric acid stones and 248 non-uric acid stones. No difference was found for uric acid stone at 80 kV and 140 kV (375.8±69.2 HU vs. 374.1±69.4 HU; t=-0.217, P=0.830), while CT values of non-uric acid stones were higher at 80 kV than those at 140 kV (1455.1±312.4 HU vs. 1039.6±194.4 HU; t=-12.16. P<0.001). CT values of non-uric acid stones at 80 kV, 140 kV, and average weighted images (1455.1±312.4 HU, 1 039.6±194.4 HU, and 882.0±176.4 HU, respectively) were higher than those of uric acid stones (375.8±69.2 HU, 374.1±69.4 HU, and 366.3±80.1 HU, respectively; P<0.001). With infrared spectrum findings as reference standard, the accuracy of dual energy CT in differentiating uric acid stones from non-uric acid stones was 100%. Conclusions: Dual-source, dual-energy CT can accurately differentiate uric acid stones from non-uric acid stones, and plays an important role in treatment planning of renal stones. (authors)

High order mode damping in a pill box cavity

International Nuclear Information System (INIS)

Voelker, F.; Lambertson, G.; Rimmer, R.

1991-04-01

We have substantially damped the higher order modes (HOM's) in a pill box cavity with attached beam pipe, while reducing the Q of the principal mode by less that 10%. This was accomplished by cutting slots in the cavity end wall at a radius at which the magnetic field of the lowest frequency HOM's is large. The slots couple energy from the cavity into waveguides which are below cut off for the principal mode, but which propagate energy at the HOM frequencies. Three slots 120 degrees apart couple HOM energy to three waveguides. We are concerned primarily with accelerating and deflecting modes: i.e. the TM mnp modes of order m=0 and m=1. For the strongest damping, only three m=0 and m=1 modes were detectable. These were the principal TM 010 mode, the TM 011 longitudinal mode, and the TM 110 deflecting mode. In addition the HOM Q's and the reduction of Q for the principal mode were determined by computer calculation. The principal mode Q for an actual rf cavity could not be measured because the bolted joints used in the construction of the cavity were not sufficiently good to support Q's above 6000. The measured Q of the first longitudinal mode was 31 and of the first transverse mode 37. Our maximum damping was limited by how well we could terminated the waveguides, and indeed, the computer calculations for the TM 011 and TM 110 modes give values in the range we measured. 2 refs., 2 figs

Mathematical model for the preliminary analysis of dual-mode space nuclear fission solid core power and propulsion systems, NUROC3A. AMS report No. 1239a

Energy Technology Data Exchange (ETDEWEB)

Grey, J.; Chow, S.

1976-06-30

The three-volume report describes a dual-mode nuclear space power and propulsion system concept that employs an advanced solid-core nuclear fission reactor coupled via heat pipes to one of several electric power conversion systems. Such a concept could be particularly useful for missions which require both relatively high acceleration (e.g., for planetocentric maneuvers) and high performance at low acceleration (e.g., on heliocentric trajectories or for trajectory shaping). The first volume develops the mathematical model of the system.

The Development of CyberLearning in Dual-Mode: Higher Education Institutions in Taiwan

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Yau-Jane Chen

2002-01-01

Full Text Available Open and distance education in Taiwan has evolved into the third phase – cyberlearning – conceptualized as teaching and learning interactions mediated entirely through the application of state-of-the-art information and communications technologies (ICT, such as the Internet and World Wide Web. Socio-economic influences, the development of new technologies and a marked shift in learning paradigms have increased the utilization of ICT at all levels of the Taiwanese education system. Since the advent and provision of cyberlearning programs, well over half (56 percent of the conventional universities and colleges have been upgraded to dual-mode higher educational institutions. They offer real-time multicast instructional systems using videoconferencing and cable TV technology, virtual classroom systems via network-based instructional management systems, and curriculum-on-demand systems utilizing video-on-demand technology. Critical success factors in the development of these cyber universities and the opportunities, challenges and implications inherent in these are analyzed. ICT and the provision of cyberlearning have gradually been changing the structure and vision of higher education institutions as well as the entire learning environment and educational systems. Because the Ministry of Education (MOE has initiated a policy on credit-based degrees for cyberlearning courses/ programs, the development of open and distance education is anticipated to hasten the transformation of Taiwan’s education system towards one which will create an ideal learning society in the 21st century.

Compressed Biogas-Diesel Dual-Fuel Engine Optimization Study for Ultralow Emission

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Hasan Koten

2014-06-01

Full Text Available The aim of this study is to find out the optimum operating conditions in a diesel engine fueled with compressed biogas (CBG and pilot diesel dual-fuel. One-dimensional (1D and three-dimensional (3D computational fluid dynamics (CFD code and multiobjective optimization code were employed to investigate the influence of CBG-diesel dual-fuel combustion performance and exhaust emissions on a diesel engine. In this paper, 1D engine code and multiobjective optimization code were coupled and evaluated about 15000 cases to define the proper boundary conditions. In addition, selected single diesel fuel (dodecane and dual-fuel (CBG-diesel combustion modes were modeled to compare the engine performances and exhaust emission characteristics by using CFD code under various operating conditions. In optimization study, start of pilot diesel fuel injection, CBG-diesel flow rate, and engine speed were optimized and selected cases were compared using CFD code. CBG and diesel fuels were defined as leading reactants using user defined code. The results showed that significantly lower NOx emissions were emitted under dual-fuel operation for all cases compared to single-fuel mode at all engine load conditions.

Degree of conversion and bond strength of resin-cements to feldspathic ceramic using different curing modes

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Veridiana Resende NOVAIS

Full Text Available Abstract Resin cements have led to great advances in dental ceramic restoration techniques because of their ability to bond to both dental structures and restorative materials. Objective The aim of this study was to assess the performance of resin cements when different curing modes are used, by evaluating the degree of conversion and bond strength to a ceramic substrate. Material and Methods Three resin cements were evaluated, two dual-cured (Variolink II and RelyX ARC and one light-cured (Variolink Veneer. The dual-cured resin cements were tested by using the dual activation mode (base and catalyst and light-activation mode (base paste only. For degree of conversion (DC (n=5, a 1.0 mm thick feldspathic ceramic disc was placed over the resin cement specimens and the set was light activated with a QTH unit. After 24 h storage, the DC was measured with Fourier transform infrared spectroscopy (FTIR. For microshear bond strength testing, five feldspathic ceramic discs were submitted to surface treatment, and three cylindrical resin cement specimens were bonded to each ceramic surface according to the experimental groups. After 24 h, microshear bond testing was performed at 0.5 mm/min crosshead speed until the failure. Data were submitted to one-way ANOVA followed by Tukey test (p<0.05. Scanning electron microscopy (SEM was used for classifying the failure modes. Results Higher DC and bond strength values were shown by the resin cements cured by using the dual activation mode. The Variolink II group presented higher DC and bond strength values when using light-activation only when compared with the Variolink Veneer group. Conclusion The base paste of dual-cured resin cements in light-activation mode can be used for bonding translucent ceramic restorations of up to or less than 1.0 mm thick.

Bistable switching in dual-frequency liquid crystals

Energy Technology Data Exchange (ETDEWEB)

Palto, S. P., E-mail: palto@online.ru; Barnik, M I [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

2006-06-15

Various bistable switching modes in nematic liquid crystals with frequency inversion of the sign of dielectric anisotropy are revealed and investigated. Switching between states with different helicoidal distributions of the director field of a liquid crystal, as well as between uniform and helicoidal states, is realized by dual-frequency waveforms of a driving voltage. A distinctive feature of the dual-frequency switching is that the uniform planar distribution of the director field may correspond to a thermodynamically equilibrium state, and the chirality of an LC is not a necessary condition for switching to a helicoidal state.

A bidirectional dual-comb ring laser for simple and robust dual-comb spectroscopy

OpenAIRE

Ideguchi, Takuro; Nakamura, Tasuku; Kobayashi, Yohei; Goda, Keisuke

2015-01-01

Fourier-transform spectroscopy is an indispensable tool for analyzing chemical samples in scientific research as well as chemical and pharmaceutical industries. Recently, its measurement speed, sensitivity, and precision have been shown to be significantly enhanced by using dual frequency combs. However, wide acceptance of this technique is hindered by its requirement for two frequency combs and active stabilization of the combs. Here we overcome this predicament with a Kerr-lens mode-locked ...

A Novel Approach to Synthesise a Dual-Mode Luminescent Composite Pigment for Uncloneable High-Security Codes to Combat Counterfeiting.

Science.gov (United States)

Kanika; Kumar, Pawan; Singh, Satbir; Gupta, Bipin Kumar

2017-12-01

A strategy is demonstrated to protect valuable items, such as currency, pharmaceuticals, important documents, etc. against counterfeiting, by marking them with luminescent security codes. These luminescent security codes were printed by employing luminescent ink formulated from a cost effective dual-mode luminescent composite pigment of Gd 1.7 Yb 0.2 Er 0.1 O 3 and Zn 0.98 Mn 0.02 S phosphors using commercially available PVC Gold medium. In the composite, Gd 1.7 Yb 0.2 Er 0.1 O 3 and Zn 0.98 Mn 0.02 S account for upconversion and downconversion processes, respectively. The synthesis procedure of the composite involves the admixing of Gd 1.7 Yb 0.2 Er 0.1 O 3 nanorods and Zn 0.98 Mn 0.02 S phosphor, synthesised by hydrothermal and facile solid-state reaction methods, respectively. The structural, morphological, microstructural, and photoluminescent features of Gd 1.7 Yb 0.2 Er 0.1 O 3 nanorods, Zn 0.98 Mn 0.02 S phosphor and composite were characterised by using XRD, SEM, TEM, and photoluminescence (PL) techniques, respectively. The distribution of PL intensity of the printed pattern was examined by using confocal PL mapping microscopy. The obtained results reveal that security codes printed using ink formulated from this bi-luminescent composite pigment provide dual-stage security against counterfeiting. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Performance Evaluation of Dual-axis Tracking System of Parabolic Trough Solar Collector

Science.gov (United States)

Ullah, Fahim; Min, Kang

2018-01-01

A parabolic trough solar collector with the concentration ratio of 24 was developed in the College of Engineering; Nanjing Agricultural University, China with the using of the TracePro software an optical model built. Effects of single-axis and dual-axis tracking modes, azimuth and elevating angle tracking errors on the optical performance were investigated and the thermal performance of the solar collector was experimentally measured. The results showed that the optical efficiency of the dual-axis tracking was 0.813% and its year average value was 14.3% and 40.9% higher than that of the eat-west tracking mode and north-south tracking mode respectively. Further, form the results of the experiment, it was concluded that the optical efficiency was affected significantly by the elevation angle tracking errors which should be kept below 0.6o. High optical efficiency could be attained by using dual-tracking mode even though the tracking precision of one axis was degraded. The real-time instantaneous thermal efficiency of the collector reached to 0.775%. In addition, the linearity of the normalized efficiency was favorable. The curve of the calculated thermal efficiency agreed well with the normalized instantaneous efficiency curve derived from the experimental data and the maximum difference between them was 10.3%. This type of solar collector should be applied in middle-scale thermal collection systems.

Dual mass, H-script-spaces, self-dual gauge connections, and nonlinear gravitons with topological origin

International Nuclear Information System (INIS)

Magnon, A.; Departement de Mathematiques, Universite de Clermont-Fd. 63170 Aubiere, France)

1986-01-01

An analogy between source-free, asymptotically Taub--NUT magnetic monopole solutions to Einstein's equation and self-(anti-self-) dual gauge connections is displayed, which finds its origin in the first Chern class of these space-times. A definition of asymptotic graviton modes is proposed that suggests that a subclass of Penrose's nonlinear gravitons or Newman's H-script-spaces could emerge from nontrivial space-time topologies

Integration of Multilocus Genetic Risk into the Default Mode Network Longitudinal Trajectory during the Alzheimer's Disease Process.

Science.gov (United States)

Su, Fan; Shu, Hao; Ye, Qing; Xie, Chunming; Yuan, Baoyu; Zhang, Zhijun; Bai, Feng

2017-01-01

The aim of the study was to investigate the cognitive significance of the changes in default mode network (DMN) during the process of Alzheimer's disease (AD) and the genetic basis that drives the alteration. Eighty-seven subjects with mild cognitive impairment (MCI) and 131 healthy controls (HC) were employed at baseline, and they had the genetic risk scores (GRS) based on the GWAS-validated AD-related top loci. Eleven MCIs who converted to AD (c-MCIs), 32 subjects who remained stable (nc-MCIs), and 56 HCs participated in the follow-up analyses after an average of 35 months. Decreased functional connectivity (FC) within temporal cortex was identified for MCIs at baseline, which was partially determined by the GRS; moreover, compensations may occur within the frontal-parietal brain to maintain relatively intact cognition. During the follow-ups, c-MCIs exhibited more FC declines within the prefrontal-parietal lobes and parahippocampal gyrus/hippocampus than the HCs and nc-MCIs. The GRS did not significantly vary among the three groups, whereas associations were identified at risky alleles and FC declines in all AD spectra. Interestingly, the influence of APOEɛ4 varied as the disease progressed; APOEɛ4 was associated with longitudinal FC decreases only for HCs in the single variance-based analyses and deteriorated DMN integration in nc-MCIs by combining the effects of other loci. However, the GRS without APOEɛ4 predicted FC decline for converters. It is suggested that the integration of multilocus genetic risk predicted the longitudinal trajectory of DMN and may be used as a clinical strategy to track AD progression.

Desempeño y emisiones de un motor de combustión interna con combustible dual Diesel – Gas natural ;Performance and emissions study of an internal combustion engine with dual fuel diesel - natural gas

Directory of Open Access Journals (Sweden)

Juan Miguel Mantilla González

2015-04-01

Full Text Available Muchos de los problemas reportados para los sistemas duales diesel- gas natural ocurren por mala dosificación del gas. Por esta razón se adaptó un sistema de alimentación dual con inyección electrónica de gas natural a un motor de combustión interna encendido por compresión. Se plantea un diseño experimental controlando el dosado de gas natural.Como resultado se obtiene un análisis comparativo entre los valoresde desempeño y emisiones desde la operación Diesel y Diesel-Gas natural. A partir de este análisis es posible observar que el desempeño del motor no se ve afectado por la operación del motor bajo el esquema Dual Diesel-GN, es decir que el motor funcionando bajo modo dual puede sostener las cargas solicitadas al motor. También se observa que la eficiencia volumétrica mejora bajo todas las condiciones de operación dual y las emisiones son mejores sólo cuando el motor trabaja a altas cargas. Many of the problems reported for dual diesel-natural gas systems occur due to poor gas dosage. For this reason a natural gas electronic injection feeding system was adapted to a compression ignitios internal combustion engine. An experimental design controlling the natural gas dosage is considered. As a result a comparative analysis between performance and emissions from the Diesel-and diesel-Natural Gas operation is obtained. From this analysis it is possible to see that engine performance is not affected by operation of the engine under the dual mode, i.e. the motor running under dual mode can support the loads applied to the engine. It is also observed that the volumetric efficiency improves under all conditions of operation and emissions from the dual mode of operation are better only when working at high engine loads.

Twin peak high-frequency quasi-periodic oscillations as a spectral imprint of dual oscillation modes of accretion tori

Science.gov (United States)

Bakala, P.; Goluchová, K.; Török, G.; Šrámková, E.; Abramowicz, M. A.; Vincent, F. H.; Mazur, G. P.

2015-09-01

Context. High-frequency (millisecond) quasi-periodic oscillations (HF QPOs) are observed in the X-ray power-density spectra of several microquasars and low-mass X-ray binaries. Two distinct QPO peaks, so-called twin peak QPOs, are often detected simultaneously exhibiting their frequency ratio close or equal to 3:2. A widely discussed class of proposed QPOs models is based on oscillations of accretion toroidal structures orbiting in the close vicinity of black holes or neutron stars. Aims: Following the analytic theory and previous studies of observable spectral signatures, we aim to model the twin peak QPOs as a spectral imprint of specific dual oscillation regime defined by a combination of the lowest radial and vertical oscillation mode of slender tori. We consider the model of an optically thick slender accretion torus with constant specific angular momentum. We examined power spectra and fluorescent Kα iron line profiles for two different simulation setups with the mode frequency relations corresponding to the epicyclic resonance HF QPOs model and modified relativistic precession QPOs model. Methods: We used relativistic ray-tracing implemented in the parallel simulation code LSDplus. In the background of the Kerr spacetime geometry, we analyzed the influence of the distant observer inclination and the spin of the central compact object. Relativistic optical projection of the oscillating slender torus is illustrated by images in false colours related to the frequency shift. Results: We show that performed simulations yield power spectra with the pair of dominant peaks that correspond to the frequencies of radial and vertical oscillation modes and with the peak frequency ratio equal to the proper value 3:2 on a wide range of inclinations and spin values. We also discuss exceptional cases of a very low and very high inclination, as well as unstable high spin relativistic precession-like configurations that predict a constant frequency ratio equal to 1:2. We

Amorphous SiC/c-ZnO-Based Quasi-Lamb Mode Sensor for Liquid Environments

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Cinzia Caliendo

2017-05-01

Full Text Available The propagation of the quasi-Lamb modes along a-SiC/ZnO thin composite plates was modeled and analysed with the aim to design a sensor able to detect the changes in parameters of a liquid environment, such as added mass and viscosity changes. The modes propagation was modeled by numerically solving the system of coupled electro-mechanical field equations in three media. The mode shape, the power flow, the phase velocity, and the electroacoustic coupling efficiency (K2 of the modes were calculated, specifically addressing the design of enhanced-coupling, microwave frequency sensors for applications in probing the solid/liquid interface. Three modes were identified that have predominant longitudinal polarization, high phase velocity, and quite good K2: the fundamental quasi symmetric mode (qS0 and two higher order quasi-longitudinal modes (qL1 and qL2 with a dominantly longitudinal displacement component in one plate side. The velocity and attenuation of these modes were calculated for different liquid viscosities and added mass, and the gravimetric and viscosity sensitivities of both the phase velocity and attenuation were theoretically calculated. The present study highlights the feasibility of the a-SiC/ZnO acoustic waveguides for the development of high-frequency, integrated-circuit compatible electroacoustic devices suitable for working in a liquid environment.

DUAL TIMELIKE NORMAL AND DUAL TIMELIKE SPHERICAL CURVES IN DUAL MINKOWSKI SPACE

OpenAIRE

ÖNDER, Mehmet

2009-01-01

Abstract: In this paper, we give characterizations of dual timelike normal and dual timelike spherical curves in the dual Minkowski 3-space and we show that every dual timelike normal curve is also a dual timelike spherical curve. Keywords: Normal curves, Dual Minkowski 3-Space, Dual Timelike curves. Mathematics Subject Classifications (2000): 53C50, 53C40. DUAL MINKOWSKI UZAYINDA DUAL TIMELIKE NORMAL VE DUAL TIMELIKE KÜRESEL EĞRİLER Özet: Bu çalışmada, dual Minkowski 3-...

Quasi-Linear Polarized Modes in Y-Rotated Piezoelectric GaPO4 Plates

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Cinzia Caliendo

2014-07-01

Full Text Available The propagation of both surface and flexural acoustic plate modes along y-rotated x-propagation GaPO4 piezoelectric substrates was studied for several y-cut angles: the phase velocity and coupling coefficient dispersion curves were theoretically calculated for two different electroacoustic coupling configurations. The investigation of the acoustic field profile across the plate thickness revealed the presence of thin plate modes having polarization predominantly oriented along the propagation direction, and hence suitable for operation in liquid environment. These modes include the linearly polarized Anisimkin Jr. and the quasi longitudinal plate modes, AMs and QLs, showing a phase velocity close to that of the longitudinal bulk acoustic wave propagating in the same direction. The temperature coefficient of delay (TCD of these longitudinal modes was investigated in the −20 to 420 °C temperature range, in order to identify thermally stable or low TCD cuts. The power flow angle, i.e., the angle between the phase and group velocity vectors, was also estimated to evaluate the substrate anisotropy effect on the acoustic wave propagation. The GaPO4 intrinsic properties, such as its resistance to high temperature and its chemical inertness, make it especially attractive for the development of acoustic waves-based sensors for applications in harsh liquid environment.

Application of dual volume reconstruction technique in embolization of intracranial aneurysms

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Xiang-hai ZHANG

2014-03-01

Full Text Available Objective　To explore the value of dual volume reconstruction technique in Guglielmi detachable coil (GDC embolization of intracranial aneurysms. Methods　Three-dimensional imaging data of 20 patients received GDC embolization of intracranial aneurysms from Jun. 2012 to Apr. 2013 were analyzed for dual volume reconstruction. The value of application of dual volume reconstruction was evaluated by the detection rate of coils bolus, degree of aneurysm occlusion, the length of aneurysm sac and aneurysm neck before and after embolization, and the characteristics and clinical value of the reconstructed images. Results 　A total of 20 coil boluses were detected by dual volume reconstruction images, and the detection rate was 100%. Among all of 20 patients, no visualization of contrast medium in the aneurysm was found in 13 patients, while contrast agent was found in the aneurysm sac in 3 patients and in the aneurysm neck in 4 patients. The length of aneurysm neck and sac was somewhat changed before and after embolization with no statistically significant difference (P>0.05. The dual volume reconstruction could reveal coil bolus, vessels, cranium and fusion images, and the aneurysms could be shown by different imaging modes according to the clinical requirement. Conclusion　Dual volume reconstruction technique can display the location of coil bolus, degree of occlusion and aneurysm size, and evaluate the embolization effect by multifarious imaging modes, providing a great deal of information for the evaluation of GDC embolization of intracranial aneurysm. DOI: 10.11855/j.issn.0577-7402.2014.02.13

Coordination in the Decentralized Assembly System with Dual Supply Modes

Directory of Open Access Journals (Sweden)

Xu Guan

2013-01-01

Full Text Available This paper investigates a decentralized assembly system that consists of one assembler and two independent suppliers; wherein one supplier is perfectly reliable for the production, while the other generates yield uncertainty. Facing the random market demand, the assembler has to order the components from one supplier in advance and meanwhile requires the other supplier to deliver the components under VMI mode. We construct a Nash game between the supplier and the assembler so as to derive their equilibrium procurement/production strategies. The results show that the channel’s performance is highly undermined by the decentralization between players and also the combination of two supply modes. Compared to the centralized system, we propose an advance payment contract to perfectly coordinate the supply chain performance. The numerical examples indicate some management implications on the supply mode comparison and sensitivity analysis.

NIR optimized dual mode photoluminescence in Nd doped Y{sub 2}O{sub 3} ceramic phosphor

Energy Technology Data Exchange (ETDEWEB)

Sukul, Prasenjit Prasad; Mahata, Manoj Kumar; Kumar, Kaushal, E-mail: kumar.bhu@gmail.com

2017-05-15

Authors here report the dual mode photo luminescence emission in neodymium doped yttrium oxide ceramic phosphor upon 808 nm diode laser excitation. Single cubic phase Nd{sup 3+} doped Y{sub 2}O{sub 3} phosphor was synthesized using urea assisted combustion route. Nd{sup 3+} doped Y{sub 2}O{sub 3} ceramic phosphor has given photoluminescence in a wide wavelength range covering near infrared window (850–1100 nm) to the visible region i.e. green (525 nm) and red (680 nm) upon 808 nm diode laser excitation. The two most intense bands on 808 nm excitation were observed at 750 nm and 1064 nm due to the upconversion and downconversion emission processes. The sample was also tested for emission using 980 nm and intense green emission due to the trace presence of Er{sup 3+} in the raw materials was seen in the sample. The excitation power dependent upconversion measurements have shown that transitions {sup 4}F{sub 9/2}→{sup 4}I{sub 9/2} and {sup 4}S{sub 3/2}→{sup 4}I{sub 9/2} are thermally coupled and can be used to estimate the sample temperature using Boltzmann relation.

Adaptive real-time dual-comb spectroscopy

Science.gov (United States)

Ideguchi, Takuro; Poisson, Antonin; Guelachvili, Guy; Picqué, Nathalie; Hänsch, Theodor W.

2014-01-01

The spectrum of a laser frequency comb consists of several hundred thousand equally spaced lines over a broad spectral bandwidth. Such frequency combs have revolutionized optical frequency metrology and they now hold much promise for significant advances in a growing number of applications including molecular spectroscopy. Despite an intriguing potential for the measurement of molecular spectra spanning tens of nanometres within tens of microseconds at Doppler-limited resolution, the development of dual-comb spectroscopy is hindered by the demanding stability requirements of the laser combs. Here we overcome this difficulty and experimentally demonstrate a concept of real-time dual-comb spectroscopy, which compensates for laser instabilities by electronic signal processing. It only uses free-running mode-locked lasers without any phase-lock electronics. We record spectra spanning the full bandwidth of near-infrared fibre lasers with Doppler-limited line profiles highly suitable for measurements of concentrations or line intensities. Our new technique of adaptive dual-comb spectroscopy offers a powerful transdisciplinary instrument for analytical sciences. PMID:24572636

Adaptive real-time dual-comb spectroscopy

Science.gov (United States)

Ideguchi, Takuro; Poisson, Antonin; Guelachvili, Guy; Picqué, Nathalie; Hänsch, Theodor W.

2014-02-01

The spectrum of a laser frequency comb consists of several hundred thousand equally spaced lines over a broad spectral bandwidth. Such frequency combs have revolutionized optical frequency metrology and they now hold much promise for significant advances in a growing number of applications including molecular spectroscopy. Despite an intriguing potential for the measurement of molecular spectra spanning tens of nanometres within tens of microseconds at Doppler-limited resolution, the development of dual-comb spectroscopy is hindered by the demanding stability requirements of the laser combs. Here we overcome this difficulty and experimentally demonstrate a concept of real-time dual-comb spectroscopy, which compensates for laser instabilities by electronic signal processing. It only uses free-running mode-locked lasers without any phase-lock electronics. We record spectra spanning the full bandwidth of near-infrared fibre lasers with Doppler-limited line profiles highly suitable for measurements of concentrations or line intensities. Our new technique of adaptive dual-comb spectroscopy offers a powerful transdisciplinary instrument for analytical sciences.

Accuracy of Combined Computed Tomography Colonography and Dual Energy Iiodine Map Imaging for Detecting Colorectal masses using High-pitch Dual-source CT.

Science.gov (United States)

Sun, Kai; Han, Ruijuan; Han, Yang; Shi, Xuesen; Hu, Jiang; Lu, Bin

2018-02-28

To evaluate the diagnostic accuracy of combined computed tomography colonography (CTC) and dual-energy iodine map imaging for detecting colorectal masses using high-pitch dual-source CT, compared with optical colonography (OC) and histopathologic findings. Twenty-eight consecutive patients were prospectively enrolled in this study. All patients were underwent contrast-enhanced CTC acquisition using dual-energy mode and OC and pathologic examination. The size of the space-occupied mass, the CT value after contrast enhancement, and the iodine value were measured and statistically compared. The sensitivity, specificity, accuracy rate, and positive predictive and negative predictive values of dual-energy contrast-enhanced CTC were calculated and compared between conventional CTC and dual-energy iodine images. The iodine value of stool was significantly lower than the colonic neoplasia (P dual-energy iodine maps imaging was 95.6% (95% CI = 77.9%-99.2%). The specificity of the two methods was 42.8% (95% CI = 15.4%-93.5%) and 100% (95% CI = 47.9%-100%; P = 0.02), respectively. Compared with optical colonography and histopathology, combined CTC and dual-energy iodine maps imaging can distinguish stool and colonic neoplasia, distinguish between benign and malignant tumors initially and improve the diagnostic accuracy of CTC for colorectal cancer screening.

Design and analysis of a novel dual-mass MEMS resonant output gyroscope

Directory of Open Access Journals (Sweden)

Yang Gao

2018-02-01

Full Text Available This paper presents the design and analysis of a novel dual-mass microelectromechanical systems (MEMS resonant output gyroscope (ROG, which can effectively eliminate the influence of common-mode disturbance, such as the linear acceleration, on the gyroscope working mode by the design of dual-mass form, as well as on the frequency outputs of the double-ended tuning fork (DETF resonators by the differential arrangement. The concept of the ROG is introduced first. Then the dynamics of the gyroscope and the force-frequency characteristics of the DETF resonator are theoretically analyzed. By establishing the distribution coefficient of force and the reasonable equivalent of the force-frequency characteristics of the DETF resonator, the accurate expression of the device sensitivity is obtained. Based on the analysis results, the leverage mechanism and the DETF resonator are designed in detail. Then the configuration of the gyroscope, a dual-mass structure, is given. Finally, the validity of the analysis and design are verified by numerical simulations.

Lifshitz quasinormal modes and relaxation from holography

NARCIS (Netherlands)

Sybesma, Watse|info:eu-repo/dai/nl/369283074; Vandoren, Stefan|info:eu-repo/dai/nl/304830739

2015-01-01

We obtain relaxation times for field theories with Lifshitz scaling and with holographic duals Einstein-Maxwell-Dilaton gravity theories. This is done by computing quasinormal modes of a bulk scalar field in the presence of Lifshitz black branes. We determine the relation between relaxation time and

Dual frequency comb metrology with one fiber laser

Science.gov (United States)

Zhao, Xin; Takeshi, Yasui; Zheng, Zheng

2016-11-01

Optical metrology techniques based on dual optical frequency combs have emerged as a hotly studied area targeting a wide range of applications from optical spectroscopy to microwave and terahertz frequency measurement. Generating two sets of high-quality comb lines with slightly different comb-tooth spacings with high mutual coherence and stability is the key to most of the dual-comb schemes. The complexity and costs of such laser sources and the associated control systems to lock the two frequency combs hinder the wider adoption of such techniques. Here we demonstrate a very simple and rather different approach to tackle such a challenge. By employing novel laser cavity designs in a mode-locked fiber laser, a simple fiber laser setup could emit dual-comb pulse output with high stability and good coherence between the pulse trains. Based on such lasers, comb-tooth-resolved dual-comb optical spectroscopy is demonstrated. Picometer spectral resolving capability could be realized with a fiber-optic setup and a low-cost data acquisition system and standard algorithms. Besides, the frequency of microwave signals over a large range can be determined based on a simple setup. Our results show the capability of such single-fiber-laser-based dual-comb scheme to reduce the complexity and cost of dual-comb systems with excellent quality for different dual-comb applications.

Optimization and Model Validation of Operation Control Strategies for a Novel Dual-Motor Coupling-Propulsion Pure Electric Vehicle

Directory of Open Access Journals (Sweden)

Jianjun Hu

2018-03-01

Full Text Available The strict operational condition of driving motors for vehicles propels the development of more complicated configurations in pure electric vehicles (PEVs. Multi-power-source powertrain configurations are one of the efficient technologies to reduce the manufacturing difficulty of driving motors. However, most of the existing studies are predominantly focused on optimal designs of powertrains and power distribution between the engine and motor of hybrid electric vehicles, which are not appropriate for PEVs. This paper proposes a novel dual-motor coupling-propulsion powertrain system that improves the dynamic and economic performance of the powertrain system in PEVs. The proposed powertrain system can realize both the single-motor driving mode and dual-motor coupling driving mode. The driving modes are divided and a power distribution strategy for the different driving modes based on an optimal system efficiency rule is employed, which enhances the performance of the proposed system. Further, a mode-switching strategy that ensures driving comfort by preventing jerk during mode switching is incorporated into the system. The results of comparative evaluations that were conducted using a dual-motor electric vehicle model implemented in MATLAB/Simulink, indicate that the mileage and dynamic performance of the proposed powertrain system are significantly better than those of the traditional single-motor powertrain system.

THE EFFECTS OF MAGNETIC-FIELD GEOMETRY ON LONGITUDINAL OSCILLATIONS OF SOLAR PROMINENCES

International Nuclear Information System (INIS)

Luna, M.; Díaz, A. J.; Karpen, J.

2012-01-01

We investigate the influence of the geometry of the solar filament magnetic structure on the large-amplitude longitudinal oscillations. A representative filament flux tube is modeled as composed of a cool thread centered in a dipped part with hot coronal regions on either side. We have found the normal modes of the system and establish that the observed longitudinal oscillations are well described with the fundamental mode. For small and intermediate curvature radii and moderate to large density contrast between the prominence and the corona, the main restoring force is the solar gravity. In this full wave description of the oscillation a simple expression for the oscillation frequencies is derived in which the pressure-driven term introduces a small correction. We have also found that the normal modes are almost independent of the geometry of the hot regions of the tube. We conclude that observed large-amplitude longitudinal oscillations are driven by the projected gravity along the flux tubes and are strongly influenced by the curvature of the dips of the magnetic field in which the threads reside.

The Effects of Magnetic-field Geometry on Longitudinal Oscillaitons of Solar Prominences

Science.gov (United States)

Luna, M.; Diaz, A. J.; Karpen, J.

2013-01-01

We investigate the influence of the geometry of the solar filament magnetic structure on the large-amplitude longitudinal oscillations. A representative filament flux tube is modeled as composed of a cool thread centered in a dipped part with hot coronal regions on either side.We have found the normal modes of the system and establish that the observed longitudinal oscillations are well described with the fundamental mode. For small and intermediate curvature radii and moderate to large density contrast between the prominence and the corona, the main restoring force is the solar gravity. In this full wave description of the oscillation a simple expression for the oscillation frequencies is derived in which the pressure-driven term introduces a small correction. We have also found that the normal modes are almost independent of the geometry of the hot regions of the tube. We conclude that observed large-amplitude longitudinal oscillations are driven by the projected gravity along the flux tubes and are strongly influenced by the curvature of the dips of the magnetic field in which the threads reside.

Ghost free dual vector theories in 2+1 dimensions

International Nuclear Information System (INIS)

Dalmazi, Denis

2006-01-01

We explore here the issue of duality versus spectrum equivalence in dual theories generated through the master action approach. Specifically we examine a generalized self-dual (GSD) model where a Maxwell term is added to the self-dual model. A gauge embedding procedure applied to the GSD model leads to a Maxwell-Chern-Simons (MCS) theory with higher derivatives. We show here that the latter contains a ghost mode contrary to the original GSD model. By figuring out the origin of the ghost we are able to suggest a new master action which interpolates between the local GSD model and a nonlocal MCS model. Those models share the same spectrum and are ghost free. Furthermore, there is a dual map between both theories at classical level which survives quantum correlation functions up to contact terms. The remarks made here may be relevant for other applications of the master action approach

Transformation of QSPA plasma streams in longitudinal magnetic field

International Nuclear Information System (INIS)

Makhlaj, V.A.; Bandura, A.N.; Chebotarev, V.V.; Kulik, N.V.; Wuerz, H.

2002-01-01

The main aim of this work is analysis of efficiency of QSPA powerful plasma streams transportation in longitudinal magnetic field in dependence on operational mode of accelerator and plasma stream parameters

Single-Layer, Dual-Port, Dual-Band, and Orthogonal-Circularly Polarized Microstrip Antenna Array with Low Frequency Ratio

Directory of Open Access Journals (Sweden)

Min Wang

2018-01-01

Full Text Available A single-layer, dual-port, dual-band, and dual circularly polarized (CP microstrip array is designed for satellite communication in this paper. The operating frequencies are 8.2 and 8.6 GHz with a very low ratio of 1.05. First, a rectangular patch element is fed through microstrip lines at two orthogonal edges to excite two orthogonal dominant modes of TM01 and TM10. The very low frequency ratio can be realized with high polarization isolations. Then, a 2-by-2 dual-band dual-CP subarray is constructed by two independent sets of sequentially rotated (SR feed structures. An 8-by-8 array is designed on the single-layer thin substrate. Finally, by utilizing one-to-four power dividers and semirigid coaxial cables, a 16-by-16 array is developed to achieve higher gain. Measured results show that the 16-by-16 array has 15 dB return loss (RL bandwidths of 4.81% and 6.75% and 3 dB axial ratio (AR bandwidths of 2.84% and 1.57% in the lower and the upper bands, respectively. Isolations of 18.6 dB and 19.4 dB and peak gains of 25.1 dBic and 25.6 dBic are obtained at 8.2 and 8.6 GHz, respectively.

Yb{sup 3+},Er{sup 3+},Eu{sup 3+}-codoped YVO{sub 4} material for bioimaging with dual mode excitation

Energy Technology Data Exchange (ETDEWEB)

Thao, Chu Thi Bich [Department of Chemistry, Changwon National University, Changwon 641-773 (Korea, Republic of); Huy, Bui The [Department of Chemistry, Changwon National University, Changwon 641-773 (Korea, Republic of); Institute of Research and Development, Duy Tan University, K7/25 Quang Trung, Da Nang (Viet Nam); Sharipov, Mirkomil [Department of Chemistry, Changwon National University, Changwon 641-773 (Korea, Republic of); Kim, Jin-Ik. [Department of Biochemistry and Health Science, Changwon National University, Changwon 641-773 (Korea, Republic of); Dao, Van-Duong [Department of Chemical Engineering & Applied Chemistry, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Moon, Ja-Young [Department of Biochemistry and Health Science, Changwon National University, Changwon 641-773 (Korea, Republic of); Lee, Yong-Ill, E-mail: yilee@changwon.ac.kr [Department of Chemistry, Changwon National University, Changwon 641-773 (Korea, Republic of)

2017-06-01

We propose an efficient bioimaging strategy using Yb{sup 3+},Er{sup 3+},Eu{sup 3+}-triplet doped YVO{sub 4} nanoparticles which were synthesized with polymer as a template. The obtained particles possess nanoscale, uniform, and flexible excitation. The effect of Eu{sup 3+} ions on the luminescence properties of YVO{sub 4}:Yb{sup 3+},Er{sup 3+},Eu{sup 3+} was investigated. The upconversion mechanism of the prepared material was also discussed. The structure and optical properties of the prepared material were characterized by using X-ray diffraction (XRD), Fourier-transform IR spectroscopy (FTIR), scanning electron microscopy (SEM), Transmission electron microscopy (TEM) upconversion and photoluminescence spectra. The Commission International de I′Eclairage (CIE) chromaticity coordinates was investigated to confirm the performance of color luminescent emission. The prepared YVO{sub 4}:Yb{sup 3+},Er{sup 3+},Eu{sup 3+} nanoparticles could be easily dispersed in water by surface modification with cysteine (Cys) and glutathione (GSH). The aqueous dispersion of the modified YVO{sub 4}:Yb{sup 3+},Er{sup 3+},Eu{sup 3+} exhibits bright upconversion and downconversion luminescence and has been applied for bioimaging of HeLa cells. Our developed material with dual excitation offers a promising advance in bioimaging. - Highlights: • Prepared particles possess nanoscale size, uniform, and larger scale. • The material exhibits strong emission under dual mode excitations. • The surface material has been applied for bioimaging of HeLa cell. • Low cytotoxicity, no auto-fluorescence.

LONGITUDINAL OSCILLATIONS IN DENSITY STRATIFIED AND EXPANDING SOLAR WAVEGUIDES

Energy Technology Data Exchange (ETDEWEB)

Luna-Cardozo, M. [Instituto de Astronomia y Fisica del Espacio, CONICET-UBA, CC. 67, Suc. 28, 1428 Buenos Aires (Argentina); Verth, G. [School of Computing, Engineering and Information Sciences, Northumbria University, Newcastle Upon Tyne NE1 8ST (United Kingdom); Erdelyi, R., E-mail: mluna@iafe.uba.ar, E-mail: robertus@sheffield.ac.uk, E-mail: gary.verth@northumbria.ac.uk [Solar Physics and Space Plasma Research Centre (SP2RC), University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH (United Kingdom)

2012-04-01

Waves and oscillations can provide vital information about the internal structure of waveguides in which they propagate. Here, we analytically investigate the effects of density and magnetic stratification on linear longitudinal magnetohydrodynamic (MHD) waves. The focus of this paper is to study the eigenmodes of these oscillations. It is our specific aim to understand what happens to these MHD waves generated in flux tubes with non-constant (e.g., expanding or magnetic bottle) cross-sectional area and density variations. The governing equation of the longitudinal mode is derived and solved analytically and numerically. In particular, the limit of the thin flux tube approximation is examined. The general solution describing the slow longitudinal MHD waves in an expanding magnetic flux tube with constant density is found. Longitudinal MHD waves in density stratified loops with constant magnetic field are also analyzed. From analytical solutions, the frequency ratio of the first overtone and fundamental mode is investigated in stratified waveguides. For small expansion, a linear dependence between the frequency ratio and the expansion factor is found. From numerical calculations it was found that the frequency ratio strongly depends on the density profile chosen and, in general, the numerical results are in agreement with the analytical results. The relevance of these results for solar magneto-seismology is discussed.

Optimal and fast E/B separation with a dual messenger field

Science.gov (United States)

Kodi Ramanah, Doogesh; Lavaux, Guilhem; Wandelt, Benjamin D.

2018-05-01

We adapt our recently proposed dual messenger algorithm for spin field reconstruction and showcase its efficiency and effectiveness in Wiener filtering polarized cosmic microwave background (CMB) maps. Unlike conventional preconditioned conjugate gradient (PCG) solvers, our preconditioner-free technique can deal with high-resolution joint temperature and polarization maps with inhomogeneous noise distributions and arbitrary mask geometries with relative ease. Various convergence diagnostics illustrate the high quality of the dual messenger reconstruction. In contrast, the PCG implementation fails to converge to a reasonable solution for the specific problem considered. The implementation of the dual messenger method is straightforward and guarantees numerical stability and convergence. We show how the algorithm can be modified to generate fluctuation maps, which, combined with the Wiener filter solution, yield unbiased constrained signal realizations, consistent with observed data. This algorithm presents a pathway to exact global analyses of high-resolution and high-sensitivity CMB data for a statistically optimal separation of E and B modes. It is therefore relevant for current and next-generation CMB experiments, in the quest for the elusive primordial B-mode signal.

Newer nonconventional modes of mechanical ventilation

Directory of Open Access Journals (Sweden)

Preet Mohinder Singh

2014-01-01

Full Text Available The conventional modes of ventilation suffer many limitations. Although they are popularly used and are well-understood, often they fail to match the patient-based requirements. Over the years, many small modifications in ventilators have been incorporated to improve patient outcome. The ventilators of newer generation respond to patient′s demands by additional feedback systems. In this review, we discuss the popular newer modes of ventilation that have been accepted in to clinical practice. Various intensive care units over the world have found these modes to improve patient ventilator synchrony, decrease ventilator days and improve patient safety. The various modes discusses in this review are: Dual control modes (volume assured pressure support, volume support, Adaptive support ventilation, proportional assist ventilation, mandatory minute ventilation, Bi-level airway pressure release ventilation, (BiPAP, neurally adjusted ventilatory assist and NeoGanesh. Their working principles with their advantages and clinical limitations are discussed in brief.

Dual use of combustible and electronic cigarettes: patterns and associations between products

Directory of Open Access Journals (Sweden)

Thomas Brandon

2018-03-01

The current cross-sectional findings suggest that vaping may reduce and partially replace cigarette use. However, e-cigarette dependence may increase over time without further reduction in smoking among those who maintain dual use. Future results from this longitudinal study should clarify use patterns, with implications for both tobacco intervention and policy.

Study of a dual frequency atmospheric pressure corona plasma

International Nuclear Information System (INIS)

Kim, Dan Bee; Moon, S. Y.; Jung, H.; Gweon, B.; Choe, Wonho

2010-01-01

Radio frequency mixing of 2 and 13.56 MHz was investigated by performing experimental measurements on the atmospheric pressure corona plasma. As a result of the dual frequency, length, current density, and electron excitation temperature of the plasma were increased, while the gas temperature was maintained at roughly the same level when compared to the respective single frequency plasmas. Moreover, observation of time-resolved images revealed that the dual frequency plasma has a discharge mode of 2 MHz positive streamer, 2 MHz negative glow, and 13.56 MHz continuous glow.

Suppression of Longitudinal Coupled-Bunch Instabilities at the KEK-PF

International Nuclear Information System (INIS)

Obina, T.; Tobiyama, M.; Honda, T.; Tadano, M.; Flanagan, J.W.; Mitsuhashi, T.; Cheng, W.X.; Fox, J.D.; Teytelman, D.

2012-01-01

A bunch-by-bunch feedback system has been developed to suppress longitudinal coupled-bunch instabilities at the KEK-PF. A longitudinal kicker based on a DAFNE-type overdamped cavity has been designed and installed in the ring, and a general purpose signal processor, called iGp, has been developed by the collaboration of the KEK, SLAC, and INFN-LNF. The entire feedback loop has been closed by the end of June 2007, and the feedback system has successfully suppressed the longitudinal dipole-mode instabilities up to 430 mA.

Theory and experiment of laterally coupled multi-longitudinal-mode semiconductor lasers

NARCIS (Netherlands)

Lenstra, D.; Yousefi, M.; Barsella, A.; Morthier, G.; Baets, R.G.F.; McMurtry, S.; Vilcot, J.-P.

2003-01-01

This report presents simulations and measurements of multimode dynamics in the twin-stripe laser resulting from complicated gain competition effects. The theory is based on a novel multi-longitudinal rate equations model, while accounting for both coherent and incoherent lateral coupling between the

Effect of compression ratio on performance, combustion and emission characteristics of a dual fuel diesel engine run on raw biogas

International Nuclear Information System (INIS)

Bora, Bhaskor J.; Saha, Ujjwal K.; Chatterjee, Soumya; Veer, Vijay

2014-01-01

Highlights: • Maximum brake thermal efficiency of 20.04% was obtained in dual fuel mode. • Compression ratio of 18 produced the maximum brake thermal efficiency. • Maximum replacement of diesel was found to be 79.46% at a compression ratio of 18. • CO gets reduced by 26.22% with the increase of compression ratio from 16 to18. • HC gets reduced by 41.97% with the increase of compression ratio from 16 to18. - Abstract: The energy consumption of the world is increasing at a staggering rate due to population explosion. The extensive use of energy has led to fossil fuel depletion and the rise in pollution. Renewable energy holds the key solution to these aforementioned problems. Biogas, one such renewable fuel, can be used in a diesel engine under dual fuel mode for the generation of power. This work attempts to unfold the effect of compression ratio on the performance, combustion and emission characteristics of a dual fuel diesel engine run on raw biogas. For this investigation, a 3.5 kW single cylinder, direct injection, water cooled, variable compression ratio diesel engine is converted into a biogas run dual fuel diesel engine by connecting a venturi gas mixer at the inlet manifold. Experiments have been conducted at various compression ratios (18, 17.5, 17 and 16) and under different loading conditions fixing the standard injection timing at 23° before top dead centre. At 100% load, the brake thermal efficiencies of the dual fuel mode are found to be 20.04%, 18.25%, 17.07% and 16.42% at compression ratios of 18, 17.5, 17 and 16, respectively, whereas at the same load, the diesel mode shows an efficiency of 27.76% at a compression ratio of 17.5. The maximum replacement of the precious fossil fuel is found to be 79.46%, 76.1%, 74% and 72% at compression ratios of 18, 17.5, 17 and 16, respectively at 100% load. For the dual fuel mode, on an average, there is a reduction in carbon monoxide as well as hydrocarbon emission by 26.22% and 41.97% when compression

Microscale characterization of the viscoelastic properties of hydrogel biomaterials using dual-mode ultrasound elastography.

Science.gov (United States)

Hong, Xiaowei; Stegemann, Jan P; Deng, Cheri X

2016-05-01

Characterization of the microscale mechanical properties of biomaterials is a key challenge in the field of mechanobiology. Dual-mode ultrasound elastography (DUE) uses high frequency focused ultrasound to induce compression in a sample, combined with interleaved ultrasound imaging to measure the resulting deformation. This technique can be used to non-invasively perform creep testing on hydrogel biomaterials to characterize their viscoelastic properties. DUE was applied to a range of hydrogel constructs consisting of either hydroxyapatite (HA)-doped agarose, HA-collagen, HA-fibrin, or preosteoblast-seeded collagen constructs. DUE provided spatial and temporal mapping of local and bulk displacements and strains at high resolution. Hydrogel materials exhibited characteristic creep behavior, and the maximum strain and residual strain were both material- and concentration-dependent. Burger's viscoelastic model was used to extract characteristic parameters describing material behavior. Increased protein concentration resulted in greater stiffness and viscosity, but did not affect the viscoelastic time constant of acellular constructs. Collagen constructs exhibited significantly higher modulus and viscosity than fibrin constructs. Cell-seeded collagen constructs became stiffer with altered mechanical behavior as they developed over time. Importantly, DUE also provides insight into the spatial variation of viscoelastic properties at sub-millimeter resolution, allowing interrogation of the interior of constructs. DUE presents a novel technique for non-invasively characterizing hydrogel materials at the microscale, and therefore may have unique utility in the study of mechanobiology and the characterization of hydrogel biomaterials. Copyright © 2016 Elsevier Ltd. All rights reserved.

Self-dual gauge field, its quantum fluctuations, and interacting fermions

International Nuclear Information System (INIS)

Flory, C.A.

1983-01-01

The quantum fluctuations about a self-dual background field in SU(2) are computed. The background field consists of parallel and equal uniform chromomagnetic and chromoelectric fields. Determination of the gluon fluctuations about this field yields zero modes, which are naturally regularized by the introduction of massless fermions. This regularization makes the integrals over all fluctuations convergent, and allows a simple computation of the vacuum energy which is shown to be lower than the energy of the configuration of zero field strength. The regularization of the zero modes also facilitates the introduction of heavy test charges which can interact with the classical background field and also exchange virtual quanta. The formalism for introducing these heavy test charges could be a good starting point for investigating the relevant physics of the self-dual background field beyond the classical level

The theory of stability, bistability, and instability in three-mode class-A lasers

International Nuclear Information System (INIS)

Jahanpanah, J; Rahdar, A A

2014-01-01

Instability is an inevitable and common problem in all different kinds of lasers when they are oscillating in both single-and multi-mode states. Here, the stability conditions are investigated for a three-mode class-A laser. A set of linear equations is derived for the stable oscillation of the cavity central mode together with its left and right adjacent longitudinal modes. The coefficient determinant of stability equations is Hermitian and equal to zero for the roots of two diagonal arrays. In other words, the novelty of our work is to expand the stability coefficient determinant in terms of main diagonal arrays rather than for one row or one column. These diagonal roots lead to two lower and upper boundary curves in the form of a bifurcation. The lower boundary curve mimics the single-mode laser and delimits the instability region (with no above-threshold oscillating mode) from the bistability region (with two above-threshold oscillating modes). The upper boundary curve mimics the two-mode laser and delimits the bistability region from the stability region, in which all three-longitudinal modes are simultaneously oscillating in the above-threshold state. (paper)

Optical phonon modes of wurtzite InP

Science.gov (United States)

Gadret, E. G.; de Lima, M. M.; Madureira, J. R.; Chiaramonte, T.; Cotta, M. A.; Iikawa, F.; Cantarero, A.

2013-03-01

Optical vibration modes of InP nanowires in the wurtzite phase were investigated by Raman scattering spectroscopy. The wires were grown along the [0001] axis by the vapor-liquid-solid method. The A1(TO), E2h, and E1(TO) phonon modes of the wurtzite symmetry were identified by using light linearly polarized along different directions in backscattering configuration. Additionally, forbidden longitudinal optical modes have also been observed. Furthermore, by applying an extended 11-parameter rigid-ion model, the complete dispersion relations of InP in the wurtzite phase have been calculated, showing a good agreement with the Raman experimental data.

The Explicit Determinations Of Dual Plane Curves And Dual Helices In Terms Of Its Dual Curvature And Dual Torsion

OpenAIRE

Lee Jae Won; Choi Jin Ho; Jin Dae Ho

2014-01-01

In this paper, we give the explicit determinations of dual plane curves, general dual helices and dual slant helices in terms of its dual curvature and dual torsion as a fundamental theory of dual curves in a dual 3-space

The Inter-Reflexive Possibilities of Dual Observations: An Account from and through Experience

Science.gov (United States)

Barrett, Margaret S.; Mills, Janet

2009-01-01

In this article, we explore the methodological possibilities of dual observation and "inter-reflexive" interpretation as we have experienced this in a longitudinal ethnographic case study of music teaching and learning in an English cathedral choir school. Our intent here is to understand the ways in which our particular historical,…

Comparison the treatment effects between simultaneous dual frequency and single frequency irradiation of ultrasound in a murine model of breast adenocarcinoma

Directory of Open Access Journals (Sweden)

Mahboobeh Alamolhoda

2010-12-01

Full Text Available Introduction: Transient cavitations induced by low frequency irradiation of ultrasound can be used to treat tumors. Previous studies in in-vitro experiments have shown that induced cavitation by dual or multiple frequencies of ultrasound is greater than induced cavitation by single frequency irradiation. In this study, we compared and evaluated the treatment effects of dual frequency irradiation of ultrasound (1 MHz and 150 kHz and single frequency irradiation in in-vivo experiments on breast adenocarcinoma tumors. Material and Method: In this study, the tumor-bearing mice were divided into 5 groups: control, sham, treated group for 30 min with 150 kHz frequency in continuous mode, another group with 1 MHz frequency in pulse mode, and treated group with combined dual frequency ultrasound (150 kHz in continuous mode and 1 MHz in 80% pulse mode. To evaluate the effects of ultrasound irradiation on tumor growth delay, the volumes of the tumors were investigated for 30 days. Tumor growth delay parameters including relative volume, inhibition ratio percentage and the required times for the tumor volume to reach to two (T2 and five (T5 times its initial volume were calculated. Results: The results showed that the treated groups with single frequency irradiation of 150 kHz continuous mode and 1 MHz pulse mode and combined dual frequency had statistically significant differences in tumor relative volume percentage during the period of 3 to 24 days after treatment (p

Coherent cavity-enhanced dual-comb spectroscopy.

Science.gov (United States)

Fleisher, Adam J; Long, David A; Reed, Zachary D; Hodges, Joseph T; Plusquellic, David F

2016-05-16

Dual-comb spectroscopy allows for the rapid, multiplexed acquisition of high-resolution spectra without the need for moving parts or low-resolution dispersive optics. This method of broadband spectroscopy is most often accomplished via tight phase locking of two mode-locked lasers or via sophisticated signal processing algorithms, and therefore, long integration times of phase coherent signals are difficult to achieve. Here we demonstrate an alternative approach to dual-comb spectroscopy using two phase modulator combs originating from a single continuous-wave laser capable of > 2 hours of coherent real-time averaging. The dual combs were generated by driving the phase modulators with step-recovery diodes where each comb consisted of > 250 teeth with 203 MHz spacing and spanned > 50 GHz region in the near-infrared. The step-recovery diodes are passive devices that provide low-phase-noise harmonics for efficient coupling into an enhancement cavity at picowatt optical powers. With this approach, we demonstrate the sensitivity to simultaneously monitor ambient levels of CO2, CO, HDO, and H2O in a single spectral region at a maximum acquisition rate of 150 kHz. Robust, compact, low-cost and widely tunable dual-comb systems could enable a network of distributed multiplexed optical sensors.

Software verification and validation methodology for advanced digital reactor protection system using diverse dual processors to prevent common mode failure

International Nuclear Information System (INIS)

Son, Ki Chang; Shin, Hyun Kook; Lee, Nam Hoon; Baek, Seung Min; Kim, Hang Bae

2001-01-01

The Advanced Digital Reactor Protection System (ADRPS) with diverse dual processors is being developed by the National Research Lab of KOPEC for ADRPS development. One of the ADRPS goals is to develop digital Plant Protection System (PPS) free of Common Mode Failure (CMF). To prevent CMF, the principle of diversity is applied to both hardware design and software design. For the hardware diversity, two different types of CPUs are used for Bistable Processor and Local Coincidence Logic Processor. The VME based Single Board Computers (SBC) are used for the CPU hardware platforms. The QNX Operating System (OS) and the VxWorks OS are used for software diversity. Rigorous Software Verification and Validation (V and V) is also required to prevent CMF. In this paper, software V and V methodology for the ADRPS is described to enhance the ADRPS software reliability and to assure high quality of the ADRPS software

Multiple player tracking in sports video: a dual-mode two-way bayesian inference approach with progressive observation modeling.

Science.gov (United States)

Xing, Junliang; Ai, Haizhou; Liu, Liwei; Lao, Shihong

2011-06-01

Multiple object tracking (MOT) is a very challenging task yet of fundamental importance for many practical applications. In this paper, we focus on the problem of tracking multiple players in sports video which is even more difficult due to the abrupt movements of players and their complex interactions. To handle the difficulties in this problem, we present a new MOT algorithm which contributes both in the observation modeling level and in the tracking strategy level. For the observation modeling, we develop a progressive observation modeling process that is able to provide strong tracking observations and greatly facilitate the tracking task. For the tracking strategy, we propose a dual-mode two-way Bayesian inference approach which dynamically switches between an offline general model and an online dedicated model to deal with single isolated object tracking and multiple occluded object tracking integrally by forward filtering and backward smoothing. Extensive experiments on different kinds of sports videos, including football, basketball, as well as hockey, demonstrate the effectiveness and efficiency of the proposed method.

Design of Dual-Band Two-Branch-Line Couplers with Arbitrary Coupling Coefficients in Bands

Directory of Open Access Journals (Sweden)

I. Prudyus

2014-12-01

Full Text Available A new approach to design dual-band two-branch couplers with arbitrary coupling coefficients at two operating frequency bands is proposed in this article. The method is based on the usage of equivalent subcircuits input reactances of the even-mode and odd-mode excitations. The exact design formulas for three options of the dual-band coupler with different location and number of stubs are received. These formulas permit to obtain the different variants for each structure in order to select the physically realizable solution and can be used in broad range of frequency ratio and power division ratio. For verification, three different dual-band couplers, which are operating at 2.4/3.9 GHz with different coupling coefficients (one with 3/6 dB, and 10/3 dB two others are designed, simulated, fabricated and tested. The measured results are in good agreement with the simulated ones.

Enhanced light scattering of the forbidden longitudinal optical phonon mode studied by micro-Raman spectroscopy on single InN nanowires

International Nuclear Information System (INIS)

Schaefer-Nolte, E O; Stoica, T; Gotschke, T; Limbach, F A; Gruetzmacher, D; Calarco, R; Sutter, E; Sutter, P

2010-01-01

In the literature, there are controversies on the interpretation of the appearance in InN Raman spectra of a strong scattering peak in the energy region of the unscreened longitudinal optical (LO) phonons, although a shift caused by the phonon-plasmon interaction is expected for the high conductance observed in this material. Most measurements on light scattering are performed on ensembles of InN nanowires (NWs). However, it is important to investigate the behavior of individual nanowires and here we report on micro-Raman measurements on single nanowires. When changing the polarization direction of the incident light from parallel to perpendicular to the wire, the expected reduction of the Raman scattering was observed for transversal optical (TO) and E 2 phonon scattering modes, while a strong symmetry-forbidden LO mode was observed independently on the laser polarization direction. Single Mg- and Si-doped crystalline InN nanowires were also investigated. Magnesium doping results in a sharpening of the Raman peaks, while silicon doping leads to an asymmetric broadening of the LO peak. The results can be explained based on the influence of the high electron concentration with a strong contribution of the surface accumulation layer and the associated internal electric field.

Enhanced Light Scattering of the Forbidden longitudinal Optical Phonon Mode Studied by Micro-Raman Spectroscopy on Single InN nanowires

International Nuclear Information System (INIS)

Sutter, E.; Schafer-Nolte, E.O.; Stoica, T.; Gotschke, T.; Limbach, F.A.; Sutter, P.; Grutzmacher, D.; Calarco, R.

2010-01-01

In the literature, there are controversies on the interpretation of the appearance in InN Raman spectra of a strong scattering peak in the energy region of the unscreened longitudinal optical (LO) phonons, although a shift caused by the phonon-plasmon interaction is expected for the high conductance observed in this material. Most measurements on light scattering are performed on ensembles of InN nanowires (NWs). However, it is important to investigate the behavior of individual nanowires and here we report on micro-Raman measurements on single nanowires. When changing the polarization direction of the incident light from parallel to perpendicular to the wire, the expected reduction of the Raman scattering was observed for transversal optical (TO) and E2 phonon scattering modes, while a strong symmetry-forbidden LO mode was observed independently on the laser polarization direction. Single Mg- and Si-doped crystalline InN nanowires were also investigated. Magnesium doping results in a sharpening of the Raman peaks, while silicon doping leads to an asymmetric broadening of the LO peak. The results can be explained based on the influence of the high electron concentration with a strong contribution of the surface accumulation layer and the associated internal electric field.

Enhanced light scattering of the forbidden longitudinal optical phonon mode studied by micro-Raman spectroscopy on single InN nanowires.

Science.gov (United States)

Schäfer-Nolte, E O; Stoica, T; Gotschke, T; Limbach, F A; Sutter, E; Sutter, P; Grützmacher, D; Calarco, R

2010-08-06

In the literature, there are controversies on the interpretation of the appearance in InN Raman spectra of a strong scattering peak in the energy region of the unscreened longitudinal optical (LO) phonons, although a shift caused by the phonon-plasmon interaction is expected for the high conductance observed in this material. Most measurements on light scattering are performed on ensembles of InN nanowires (NWs). However, it is important to investigate the behavior of individual nanowires and here we report on micro-Raman measurements on single nanowires. When changing the polarization direction of the incident light from parallel to perpendicular to the wire, the expected reduction of the Raman scattering was observed for transversal optical (TO) and E(2) phonon scattering modes, while a strong symmetry-forbidden LO mode was observed independently on the laser polarization direction. Single Mg- and Si-doped crystalline InN nanowires were also investigated. Magnesium doping results in a sharpening of the Raman peaks, while silicon doping leads to an asymmetric broadening of the LO peak. The results can be explained based on the influence of the high electron concentration with a strong contribution of the surface accumulation layer and the associated internal electric field.

Dual-Polarized Planar Phased Array Analysis for Meteorological Applications

Directory of Open Access Journals (Sweden)

Chen Pang

2015-01-01

Full Text Available This paper presents a theoretical analysis for the accuracy requirements of the planar polarimetric phased array radar (PPPAR in meteorological applications. Among many factors that contribute to the polarimetric biases, four factors are considered and analyzed in this study, namely, the polarization distortion due to the intrinsic limitation of a dual-polarized antenna element, the antenna pattern measurement error, the entire array patterns, and the imperfect horizontal and vertical channels. Two operation modes, the alternately transmitting and simultaneously receiving (ATSR mode and the simultaneously transmitting and simultaneously receiving (STSR mode, are discussed. For each mode, the polarimetric biases are formulated. As the STSR mode with orthogonal waveforms is similar to the ATSR mode, the analysis is mainly focused on the ATSR mode and the impacts of the bias sources on the measurement of polarimetric variables are investigated through Monte Carlo simulations. Some insights of the accuracy requirements are obtained and summarized.

On-chip dual-comb source for spectroscopy.

Science.gov (United States)

Dutt, Avik; Joshi, Chaitanya; Ji, Xingchen; Cardenas, Jaime; Okawachi, Yoshitomo; Luke, Kevin; Gaeta, Alexander L; Lipson, Michal

2018-03-01

Dual-comb spectroscopy is a powerful technique for real-time, broadband optical sampling of molecular spectra, which requires no moving components. Recent developments with microresonator-based platforms have enabled frequency combs at the chip scale. However, the need to precisely match the resonance wavelengths of distinct high quality-factor microcavities has hindered the development of on-chip dual combs. We report the simultaneous generation of two microresonator combs on the same chip from a single laser, drastically reducing experimental complexity. We demonstrate broadband optical spectra spanning 51 THz and low-noise operation of both combs by deterministically tuning into soliton mode-locked states using integrated microheaters, resulting in narrow (lasers or microwave oscillators. We demonstrate high signal-to-noise ratio absorption spectroscopy spanning 170 nm using the dual-comb source over a 20-μs acquisition time. Our device paves the way for compact and robust spectrometers at nanosecond time scales enabled by large beat-note spacings (>1 GHz).

Raman intensity and vibrational modes of armchair CNTs

Science.gov (United States)

Hur, Jaewoong; Stuart, Steven J.

2017-07-01

Raman intensity changes and frequency patterns have been studied using the various armchair (n, n) to understand the variations of bond polarizability, in regard to changing diameters, lengths, and the number of atoms in the (n, n). The Raman intensity trends of the (n, n) are validated by those of Cn isomers. For frequency trends, similar frequency patterns and frequency inward shifts for the (n, n) are characterized. Also, VDOS trends of the (n, n) expressing Raman modes are interpreted. The decomposition of vibrational modes in the (n, n) into radial, longitudinal, and tangential mode is beneficially used to recognize the distinct characteristics of vibrational modes.

Matrix solution to longitudinal impedance of multi-layer circular structures

Energy Technology Data Exchange (ETDEWEB)

Hahn,H.

2008-10-01

A matrix method in which radial wave propagation is treated in analogy to longitudinal transmission lines is presented and applied to finding the longitudinal coupling impedance of axially symmetric multi-layer beam tubes. The method is demonstrated in the case of a Higher Order Mode ferrite absorber with an inserted coated ceramic beam tube. The screening of the ferrite damping properties by the dielectric beam tube is discussed.

Dual mode antimony electrode for simultaneous measurements of PO2 and pH.

Science.gov (United States)

Sjöberg, F; Nilsson, G

2000-01-01

In biomedical research and clinical medicine there is a demand for potent sensors to measure the components that make up blood gas analyses. Today, as when the electrochemical PO2, PCO2 and pH electrodes were first introduced, these measurements are usually made with the same type of sensor technology. The aims of the present study were, firstly, to find out whether the platinum cathode in the Clark electrode can be replaced by antimony for oxygen measurements (amperometry (A)); secondly, whether, during oxygen measurements, the inherent corrosion potential of the antimony metal can be used for measurement of pH in the same measurement area (potentiometry (P)). An electrode of purified, crystallographically orientated monocrystalline antimony (COMA) connected to a reference electrode (silver-silver chloride) was used for the P measurements. Measurements of A (at -900 mV) and P were made in an aqueous environment regulated for oxygen, pH, and temperature. Reproducible oxygen sensitivities of 0.925 nA/% oxygen (2% CV (coefficient of variation)) (A), 10.7 mV/% (P), and 0.7 mV/% (P) were found in the oxygen range: 0-21%, <5%, and above 5%, respectively. The pH sensitivity was 57 mV/pH unit (P). Oxygen and pH measurements were less accurate at oxygen concentrations close to 0%. Both the oxygen and pH part of the composite electrode signal can be identified by this dual mode technique (A and P). The sensor seems to be promising as it provides measurements of two separate variables (oxygen and pH) and also has the desirable characteristics of a solid state sensor.

Direct detection of the optical field beyond single polarization mode.

Science.gov (United States)

Che, Di; Sun, Chuanbowen; Shieh, William

2018-02-05

Direct detection is traditionally regarded as a detection method that recovers only the optical intensity. Compared with coherent detection, it owns a natural advantage-the simplicity-but lacks a crucial capability of field recovery that enables not only the multi-dimensional modulation, but also the digital compensation of the fiber impairments linear with the optical field. Full-field detection is crucial to increase the capacity-distance product of optical transmission systems. A variety of methods have been investigated to directly detect the optical field of the single polarization mode, which normally sends a carrier traveling with the signal for self-coherent detection. The crux, however, is that any optical transmission medium supports at least two propagating modes (e.g. single mode fiber supports two polarization modes), and until now there is no direct detection that can recover the complete set of optical fields beyond one polarization, due to the well-known carrier fading issue after mode demultiplexing induced by the random mode coupling. To avoid the fading, direct detection receivers should recover the signal in an intensity space isomorphic to the optical field without loss of any degrees of freedom, and a bridge should be built between the field and its isomorphic space for the multi-mode field recovery. Based on this thinking, we propose, for the first time, the direct detection of dual polarization modes by a novel receiver concept, the Stokes-space field receiver (SSFR) and its extension, the generalized SSFR for multiple spatial modes. The idea is verified by a dual-polarization field recovery of a polarization-multiplexed complex signal over an 80-km single mode fiber transmission. SSFR can be applied to a much wider range of fields beyond optical communications such as coherent sensing and imaging, where simple field recovery without an extra local laser is desired for enhanced system performance.

Simultaneous reduction of NOx and smoke in a dual fuel DI diesel engine

International Nuclear Information System (INIS)

Barik, Debabrata; Murugan, S.

2014-01-01

Highlights: • A solution to use the de-oiled cakes disposed from oil industries. • Biogas produced from Karanja de-oiled cakes contains about 73% methane. • Simultaneous reduction of NO and smoke is possible with KME–biogas dual fuel operation. • Up to 30% replacement of KME is possible with induction of biogas at 0.9 kg/h. • Improved part load performance and emission with KME–biogas dual fuel. - Abstract: This paper presents the results of an experimental investigation conducted on a compression ignition (CI) engine, modified to run on dual fuel mode, using biogas as a primary fuel and KME (Karanja methyl ester) as a pilot fuel. The biogas was produced by anaerobic digestion of Pongamia pinnata (Karanja) seed cakes. In dual fuel mode, the biogas was inducted at four different flow rates, viz. 0.3 kg/h, 0.6 kg/h, 0.9 kg/h and 1.2 kg/h through the intake manifold of the engine. The biogas flow rate of 0.9 kg/h gave a better performance and lower emissions, than those of the other flow rates. The NO and smoke emissions were found to be lower by about 34% and 14%, than those of KME operation, at full load. The ignition delay was longer by about 1–2 °CA in the dual fuel operation, than that of KME at full load. The part load performance was found to be better in dual fuel operation, with reduced emissions of NO and smoke, in comparison with KME. The ignition delay at part load in dual fuel operation was also lower than that of KME operation

Experimental investigation on dual fuel operation of acetylene in a DI diesel engine

Energy Technology Data Exchange (ETDEWEB)

Lakshmanan, T. [Department of Mechanical Engineering, Rajarajeswari Engineering College, Adayalampattu, Chennai, 600095 (India); Nagarajan, G. [Internal Combustion Engineering Division, College of Engineering, Anna University, Chennai, 600025 (India)

2010-05-15

Depletion of fossils fuels and environmental degradation have prompted researchers throughout the world to search for a suitable alternative fuel for diesel engine. One such step is to utilize renewable fuels in diesel engines by partial or total replacement of diesel in dual fuel mode. In this study, acetylene gas has been considered as an alternative fuel for compression ignition engine, which has excellent combustion properties. Investigation has been carried out on a single cylinder, air cooled, direct injection (DI), compression ignition engine designed to develop the rated power output of 4.4 kW at 1500 rpm under variable load conditions, run on dual fuel mode with diesel as injected primary fuel and acetylene inducted as secondary gaseous fuel at various flow rates. Acetylene aspiration resulted in lower thermal efficiency. Smoke, HC and CO emissions reduced, when compared with baseline diesel operation. With acetylene induction, due to high combustion rates, NO{sub x} emission significantly increased. Peak pressure and maximum rate of pressure rise also increased in the dual fuel mode of operation due to higher flame speed. It is concluded that induction of acetylene can significantly reduce smoke, CO and HC emissions with a small penalty on efficiency. (author)

Transverse intrinsic localized modes in monatomic chain and in graphene

Energy Technology Data Exchange (ETDEWEB)

Hizhnyakov, V. [Institute of Physics, University of Tartu, Ravila 14c, 50411 Tartu (Estonia); Klopov, M. [Department of Physics, Faculty of Science, Tallinn University of Technology, Ehitajate 5, 19086 Tallinn (Estonia); Shelkan, A., E-mail: shell@ut.ee [Institute of Physics, University of Tartu, Ravila 14c, 50411 Tartu (Estonia)

2016-03-06

In this paper an analytical and numerical study of anharmonic vibrations of monatomic chain and graphene in transverse (perpendicular) with respect to the chain/plane direction is presented. Due to the lack of odd anharmonicities and presence of hard quartic anharmonicity for displacements in this direction, there may exist localized anharmonic transverse modes with the frequencies above the spectrum of the corresponding phonons. Although these frequencies are in resonance with longitudinal (chain) or in-plane (graphene) phonons, the modes can decay only due to a weak anharmonic process. Therefore the lifetime of these vibrations may be very long. E.g. in the chain, according to our theoretical and numerical calculations it may exceed 10{sup 10} periods. We call these vibrations as transverse intrinsic localized modes. - Highlights: • In a stretched monatomic chain, long-living nonlinear transverse localized modes may exist. • Transverse vibrations of a chain slowly decay due to creation of longitudinal phonons. • Lifetime of transverse vibrations of a chain may exceed billion periods of vibrations. • In stretched graphene, long-living out-of-plain localized vibrations may exist.

Dual energy CT of the chest: how about the dose?

Science.gov (United States)

Schenzle, Jan C; Sommer, Wieland H; Neumaier, Klement; Michalski, Gisela; Lechel, Ursula; Nikolaou, Konstantin; Becker, Christoph R; Reiser, Maximilian F; Johnson, Thorsten R C

2010-06-01

New generation Dual Source computed tomography (CT) scanners offer different x-ray spectra for Dual Energy imaging. Yet, an objective, manufacturer independent verification of the dose required for the different spectral combinations is lacking. The aim of this study was to assess dose and image noise of 2 different Dual Energy CT settings with reference to a standard chest scan and to compare image noise and contrast to noise ratios (CNR). Also, exact effective dose length products (E/DLP) conversion factors were to be established based on the objectively measured dose. An anthropomorphic Alderson phantom was assembled with thermoluminescent detectors (TLD) and its chest was scanned on a Dual Source CT (Siemens Somatom Definition) in dual energy mode at 140 and 80 kVp with 14 x 1.2 mm collimation. The same was performed on another Dual Source CT (Siemens Somatom Definition Flash) at 140 kVp with 0.8 mm tin filter (Sn) and 100 kVp at 128 x 0.6 mm collimation. Reference scans were obtained at 120 kVp with 64 x 0.6 mm collimation at equivalent CT dose index of 5.4 mGy*cm. Syringes filled with water and 17.5 mg iodine/mL were scanned with the same settings. Dose was calculated from the TLD measurements and the dose length products of the scanner. Image noise was measured in the phantom scans and CNR and spectral contrast were determined in the iodine and water samples. E/DLP conversion factors were calculated as ratio between the measured dose form the TLDs and the dose length product given in the patient protocol. The effective dose measured with TLDs was 2.61, 2.69, and 2.70 mSv, respectively, for the 140/80 kVp, the 140 Sn/100 kVp, and the standard 120 kVp scans. Image noise measured in the average images of the phantom scans was 11.0, 10.7, and 9.9 HU (P > 0.05). The CNR of iodine with optimized image blending was 33.4 at 140/80 kVp, 30.7 at 140Sn/100 kVp and 14.6 at 120 kVp. E/DLP conversion factors were 0.0161 mSv/mGy*cm for the 140/80 kVp protocol, 0.0181 m

A highly stable and switchable dual-wavelength laser using coupled microfiber Mach-Zehnder interferometer as an optical filter

Science.gov (United States)

Jasim, A. A.; Ahmad, H.

2017-12-01

The generation and switching of dual-wavelength laser based on compact coupled microfiber Mach-Zehnder interferometer (CM-MZI) is reported. The CM-MZI is constructed by overlapping two portions of a single tapered optical fiber which has a diameter of 9 μm as to create multi-mode interference and also to produce spatial mode beating as to suppress mode competition in the homogeneous gain medium. The system is able to generate a dual-wavelength laser output that can be switched with the aid of the polarization rotation technique. Four dual-wavelength oscillation pairs are obtained from the interference fringe peaks of the CM-MZI comb filter with a switched channel spacing of 1.5 nm, 3.0 nm, and 6.0 nm. The wavelength spacing is stable at different pump powers. The lasing wavelength has a 3-dB linewidth of about 30 pm and peak-to-floor ration of about 55 dB at a pump power of 38 mW.

Analysis of a combustion, performance and emission characteristics of a CNG-B20 fuelled diesel engine under dual fuel mode

Directory of Open Access Journals (Sweden)

Pankaj S. Shelke

2016-09-01

Full Text Available The Carbon dioxide (CO2 is one of the primary greenhouse gases emitted by various human activities. CO2 is naturally present in the atmosphere as part of carbon cycle. Human activities are altering the carbon cycle by adding or removing CO2 to the atmosphere. The main human activity that emits the CO2 is combustion of fossil fuels for energy and transportation. Compression ignition (CI engines emit high amount of CO2 emission as it is the end product of complete combustion of hydro carbon fuels. Moreover, they emit higher NOx (nitrogen oxides and PM (particulate matter emissions and have higher fuel consumption. In the present study, experimental investigations were carried out on a CI engine under dual fuel mode with biodiesel as a pilot fuel and compressed natural gas (CNG as a main fuel. The effects of 10 % and 20 % CNG energy shares on performance and emission characteristics of the engine at rated (100% loads were studied. Experimental results indicate the beneficial of CNG addition on improvement in the engine efficiency, and reduction in NOx and CO2 emissions. The NOx and CO2 emissions decreased by 14.24 % and 30 % respectively at the rated load with biodiesel + CNG (20 % energy share as compared to base diesel. No knocking combustion was observed during the tests which confirm the smooth operation. The dual fuel operation with combination of CNG-biodiesel is an effective method to reduce NOx and CO2 emissions with an additional benefit of lower specific energy consumption.

Quantum interference effects on the intensity of the G modes in double-walled carbon nanotubes

International Nuclear Information System (INIS)

Tran, Huy Nam; Blancon, Jean-Christophe Robert; Arenal, Raul

2017-01-01

The effects of quantum interferences on the excitation dependence of the intensity of G modes have been investigated on single-walled carbon nanotubes [Duque et al., Phys. Rev. Lett.108, 117404 (2012)]. In this work, by combining optical absorption spectroscopy and Raman scattering on individual index identified double-walled carbon nanotubes, we examine the experimental excitation dependence of the intensity of longitudinal optical and transverse optical G modes of the constituent inner and outer single-walled carbon nanotubes. The observed striking dependencies are understood in terms of quantum interference effects. Considering such effects, the excitation dependence of the different components of the G modes permit to unambiguously assign each of them as originating from the longitudinal or transverse G modes of inner and outer tubes.

An Exploration of Dual Systems via Time Pressure Manipulation in Decision-making Problems

OpenAIRE

Guo, Lisa

2017-01-01

Every day, decisions need to be made where time is a limiting factor. Regardless of situation, time constraints often place a premium on rapid decision-making. Researchers have been interested in studying this human behavior and understanding its underlying cognitive processes. In previous studies, scientists have believed that the cognitive processes underlying decision-making behavior were consistent with dual-process modes of thinking. Critics of dual-process theory question the vagueness ...

Simulation of the ALS longitudinal multibunch feedback system

International Nuclear Information System (INIS)

Byrd, J.

1993-05-01

Longitudinal coupled bunch growth rates in the Advanced Light Source (ALS), a 1.5 GeV electron storage ring for producing synchrotron radiation, indicate the need for damping via a feedback (FB) system. The design of the system is based on the proposed PEP-II longitudinal FB system which uses a digital filter to provide the required phase and amplitude response. We report the results of a detailed computer simulation of the FB system including single particle longitudinal beam dynamics, measured RF cavity fundamental and higher order modes, and response of major FB components such as the power amplifier and kicker. The simulation addresses issues such as required FB power and gain, noise, digital filter effects, and varying initial bunch conditions

陕西电信天翼3G双模智能机市场发展策略研究%Shanxi Telecom Tianyi 3G Dual-mode Intelligent Machine Market Development Strategy Research

Institute of Scientific and Technical Information of China (English)

贾琳

2013-01-01

中国电信陕西公司天翼3G智能终端销售在2011年至2012年间快速上升，但2012年下半年，智能机发展出现阶段性波动，增长率降低；同时竞争对手发力双模智能机，快速挖转中国移动用户。分析和论证发展天翼3G双模智能机的必要性，并从产品、价格、渠道、宣传和促销4方面提出了天翼3G双模智能机发展的具体策略，对于陕西电信进一步加快智能机的发展，拓展社会开放渠道，保持3G市场领先优势具有重要意义。%3G intelligent terminal sales of Shaanxi China Telecom Tianyi form 2011 to 2012 years the rises rapidly,but the second half of 2012, intelligent machine development stage of volatility, growth rate decreased,rival force of dual-mode intelligent machine, fast digging to China Mobile users at the same time. This paper focuses on a telecommunications enterprise employee's point of view, fully aware of the changing market environment and competition strategy, the necessity analysis and demonstration of development day wing 3G dual-mode intelligent machines, and specific strategies day wing development 3G dual-mode intelligent machine is put forward from the product, price, channel, promotion and promotion four aspects, for Shaanxi to further accelerate the development of the telecom intelligent machine, expand social open channel, it is important to keep the 3G market advantage.

FNTD radiation dosimetry system enhanced with dual-color wide-field imaging

International Nuclear Information System (INIS)

Akselrod, M.S.; Fomenko, V.V.; Bartz, J.A.; Ding, F.

2014-01-01

At high neutron and photon doses Fluorescent Nuclear Track Detectors (FNTDs) require operation in analog mode and the measurement results depend on individual crystal color center concentration (coloration). We describe a new method for radiation dosimetry using FNTDs, which includes non-destructive, automatic sensitivity calibration for each individual FNTD. In the method presented, confocal laser scanning fluorescent imaging of FNTDs is combined with dual-color wide field imaging of the FNTD. The calibration is achieved by measuring the color center concentration in the detector through fluorescence imaging and reducing the effect of diffuse reflection on the lapped surface of the FNTD by imaging with infra-red (IR) light. The dual-color imaging of FNTDs is shown to provide a good estimation of the detector sensitivity at high doses of photons and neutrons, where conventional track counting is impeded by track overlap. - Highlights: • New method and optical imaging head was developed for FNTD used at high doses. • Dual-color wide-field imaging used for color center concentration measurement. • Green fluorescence corrected by diffuse reflection used for sensitivity correction. • FNTD dose measurements performed in analog processing mode

Resolving dual binding conformations of cellulosome cohesin-dockerin complexes using single-molecule force spectroscopy.

Science.gov (United States)

Jobst, Markus A; Milles, Lukas F; Schoeler, Constantin; Ott, Wolfgang; Fried, Daniel B; Bayer, Edward A; Gaub, Hermann E; Nash, Michael A

2015-10-31

Receptor-ligand pairs are ordinarily thought to interact through a lock and key mechanism, where a unique molecular conformation is formed upon binding. Contrary to this paradigm, cellulosomal cohesin-dockerin (Coh-Doc) pairs are believed to interact through redundant dual binding modes consisting of two distinct conformations. Here, we combined site-directed mutagenesis and single-molecule force spectroscopy (SMFS) to study the unbinding of Coh:Doc complexes under force. We designed Doc mutations to knock out each binding mode, and compared their single-molecule unfolding patterns as they were dissociated from Coh using an atomic force microscope (AFM) cantilever. Although average bulk measurements were unable to resolve the differences in Doc binding modes due to the similarity of the interactions, with a single-molecule method we were able to discriminate the two modes based on distinct differences in their mechanical properties. We conclude that under native conditions wild-type Doc from Clostridium thermocellum exocellulase Cel48S populates both binding modes with similar probabilities. Given the vast number of Doc domains with predicted dual binding modes across multiple bacterial species, our approach opens up new possibilities for understanding assembly and catalytic properties of a broad range of multi-enzyme complexes.

A two-dimensional problem of a mode-I crack in a rotating fibre ...

Indian Academy of Sciences (India)

AHMED E ABOUELREGAL

2018-02-07

Feb 7, 2018 ... Fibre-reinforced; mode-I crack; dual-phase-lag theory; rotation; normal mode analysis. 1. Introduction ... acki [2, 3] rests upon the hypothesis of the Fourier law of .... forcement and rotation on the variations of different field quantities inside ... The principle of balance of linear momentum leads to the following ...

Voltage tunable plasmon propagation in dual gated bilayer graphene

Science.gov (United States)

Farzaneh, Seyed M.; Rakheja, Shaloo

2017-10-01

In this paper, we theoretically investigate plasmon propagation characteristics in AB and AA stacked bilayer graphene (BLG) in the presence of energy asymmetry due to an electrostatic field oriented perpendicularly to the plane of the graphene sheet. We first derive the optical conductivity of BLG using the Kubo formalism incorporating energy asymmetry and finite electron scattering. All results are obtained for room temperature (300 K) operation. By solving Maxwell's equations in a dual gate device setup, we obtain the wavevector of propagating plasmon modes in the transverse electric (TE) and transverse magnetic (TM) directions at terahertz frequencies. The plasmon wavevector allows us to compare the compression factor, propagation length, and the mode confinement of TE and TM plasmon modes in bilayer and monolayer graphene sheets and also to study the impact of material parameters on plasmon characteristics. Our results show that the energy asymmetry can be harnessed to increase the propagation length of TM plasmons in BLG. AA stacked BLG shows a larger increase in the propagation length than AB stacked BLG; conversely, it is very insensitive to the Fermi level variations. Additionally, the dual gate structure allows independent modulation of the energy asymmetry and the Fermi level in BLG, which is advantageous for reconfiguring plasmon characteristics post device fabrication.

Enhanced gauge symmetry and winding modes in double field theory

Energy Technology Data Exchange (ETDEWEB)

Aldazabal, G. [Centro Atómico Bariloche,8400 S.C. de Bariloche (Argentina); Instituto Balseiro (CNEA-UNC) and CONICET,8400 S.C. de Bariloche (Argentina); Graña, M. [Institut de Physique Théorique, CEA/ Saclay,91191 Gif-sur-Yvette Cedex (France); Iguri, S. [Instituto de Astronomía y Física del Espacio (CONICET-UBA), Universidad de Buenos Aires,1428 Buenos Aires (Argentina); Mayo, M. [Centro Atómico Bariloche,8400 S.C. de Bariloche (Argentina); Instituto Balseiro (CNEA-UNC) and CONICET,8400 S.C. de Bariloche (Argentina); Nuñez, C. [Instituto de Astronomía y Física del Espacio (CONICET-UBA), Universidad de Buenos Aires,1428 Buenos Aires (Argentina); Departamento de Física, FCEN, Universidad de Buenos Aires,C.C. 67 - Suc. 28, 1428 Buenos Aires (Argentina); Rosabal, J.A. [Departamento de Física, FCEN, Universidad de Buenos Aires,C.C. 67 - Suc. 28, 1428 Buenos Aires (Argentina)

2016-03-15

We provide an explicit example of how the string winding modes can be incorporated in double field theory. Our guiding case is the closed bosonic string compactified on a circle of radius close to the self-dual point, where some modes with non-zero winding or discrete momentum number become massless and enhance the U(1)×U(1) symmetry to SU(2)×SU(2). We compute three-point string scattering amplitudes of massless and slightly massive states, and extract the corresponding effective low energy gauge field theory. The enhanced gauge symmetry at the self-dual point and the Higgs-like mechanism arising when changing the compactification radius are examined in detail. The extra massless fields associated to the enhancement are incorporated into a generalized frame with ((O(d+3,d+3))/(O(d+3)×O(d+3))) structure, where d is the number of non-compact dimensions. We devise a consistent double field theory action that reproduces the low energy string effective action with enhanced gauge symmetry. The construction requires a truly non-geometric frame which explicitly depends on both the compact coordinate along the circle and its dual.

Preparation of a novel dual-function strong cation exchange/hydrophobic interaction chromatography stationary phase for protein separation.

Science.gov (United States)

Zhao, Kailou; Yang, Li; Wang, Xuejiao; Bai, Quan; Yang, Fan; Wang, Fei

2012-08-30

We have explored a novel dual-function stationary phase which combines both strong cation exchange (SCX) and hydrophobic interaction chromatography (HIC) characteristics. The novel dual-function stationary phase is based on porous and spherical silica gel functionalized with ligand containing sulfonic and benzyl groups capable of electrostatic and hydrophobic interaction functionalities, which displays HIC character in a high salt concentration, and IEC character in a low salt concentration in mobile phase employed. As a result, it can be employed to separate proteins with SCX and HIC modes, respectively. The resolution and selectivity of the dual-function stationary phase were evaluated under both HIC and SCX modes with standard proteins and can be comparable to that of conventional IEC and HIC columns. More than 96% of mass and bioactivity recoveries of proteins can be achieved in both HIC and SCX modes, respectively. The results indicated that the novel dual-function column could replace two individual SCX and HIC columns for protein separation. Mixed retention mechanism of proteins on this dual-function column based on stoichiometric displacement theory (SDT) in LC was investigated to find the optimal balance of the magnitude of electrostatic and hydrophobic interactions between protein and the ligand on the silica surface in order to obtain high resolution and selectivity for protein separation. In addition, the effects of the hydrophobicity of the ligand of the dual-function packings and pH of the mobile phase used on protein separation were also investigated in detail. The results show that the ligand with suitable hydrophobicity to match the electrostatic interaction is very important to prepare the dual-function stationary phase, and a better resolution and selectivity can be obtained at pH 6.5 in SCX mode. Therefore, the dual-function column can replace two individual SCX and HIC columns for protein separation and be used to set up two-dimensional liquid

ELMs and constraints on the H-mode pedestal: A model based on peeling-ballooning modes

International Nuclear Information System (INIS)

Snyder, P.B.

2002-01-01

Maximizing the pedestal height while maintaining acceptable ELMs is a key issue for optimizing tokamak performance. We present a model for ELMs and pedestal constraints based upon theoretical analysis of edge instabilities which can limit the pedestal height and drive ELMs. Sharp pedestal pressure gradients drive large bootstrap currents which play a complex dual role in the stability physics. Consequently, the dominant modes are often intermediate-n coupled 'peeling-ballooning' modes, driven both by current and the pressure gradient. A highly efficient new MHD code, ELITE, is used to study these modes, and calculate quantitative stability constraints on the pedestal, including direct constraints on the pedestal height. A model of various ELM types is developed, and quantitatively compared to data from several tokamaks. A number of observations agree with predictions, including ELM onset times, ELM depth, and variation in pedestal height with discharge shape. Projections of pedestal stability constraints for Next Step designs, and nonlinear simulations of peeling-ballooning modes using the BOUT code are also presented. (author)

Dual-source dual-energy CT angiography with virtual non-enhanced images and iodine map for active gastrointestinal bleeding: Image quality, radiation dose and diagnostic performance

International Nuclear Information System (INIS)

Sun, Hao; Hou, Xin-Yi; Xue, Hua-Dan; Li, Xiao-Guang; Jin, Zheng-Yu; Qian, Jia-Ming; Yu, Jian-Chun; Zhu, Hua-Dong

2015-01-01

Highlights: • GIB is a common gastrointestinal emergency with a high mortality rate. • Detection and localization of GIB source are important for imaging modality. • DSDECTA using a dual-phase scan protocol is clinically feasible. • DSDECTA with VNE and iodine map images can diagnose the active GIB source accurately. • DSDECTA can reduce radiation dose compared with conventional CT examination in GIB. - Abstract: Objectives: To evaluate the clinical feasibility of dual-source dual-energy CT angiography (DSDECTA) with virtual non-enhanced images and iodine map for active gastrointestinal bleeding (GIB). Methods: From June 2010 to December 2012, 112 consecutive patients with clinical signs of active GIB underwent DSDECTA with true non-enhanced (TNE), arterial phase with single-source mode, and portal-venous phase with dual-energy mode (100 kVp/230 mAs and Sn 140 kVp/178 mAs). Virtual non-enhanced CT (VNE) image sets and iodine map were reformatted from ‘Liver VNC’ software. The mean CT number, noise, signal to noise ratio (SNR), image quality and radiation dose were compared between TNE and VNE image sets. Two radiologists, blinded to clinical data, interpreted images from DSDECTA with TNE (protocol 1), and DSDECTA with VNE and iodine map (protocol 2) respectively, with discordant interpretation resolved by consensus. The standards of reference included digital subtraction angiography, endoscopy, surgery, or final pathology reports. Receiver–operating characteristic (ROC) analysis was undertaken and the area under the curve (AUC) calculated for CT protocols 1 and 2, respectively. Results: There was no significant difference in mean CT numbers of all organs (including liver, pancreas, spleen, kidney, abdominal aorta, and psoas muscle) (P > 0.05). Lower noise and higher SNR were found on VNE images than TNE images (P < 0.05). Image quality of VNE was lower than that of TNE without significant difference (P > 0.05). The active GIB source was identified

Dual-source dual-energy CT angiography with virtual non-enhanced images and iodine map for active gastrointestinal bleeding: Image quality, radiation dose and diagnostic performance

Energy Technology Data Exchange (ETDEWEB)

Sun, Hao, E-mail: sunhao_robert@126.com [Department of Radiology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Wangfujing Street, Dongcheng District, Beijing 100730 (China); Hou, Xin-Yi, E-mail: hxy_pumc@126.com [Department of Radiology, Beijing Tiantan Hospital, Capital Medical University, Beijing (China); Xue, Hua-Dan, E-mail: bjdanna95@hotmail.com [Department of Radiology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Wangfujing Street, Dongcheng District, Beijing 100730 (China); Li, Xiao-Guang, E-mail: xglee88@126.com [Department of Radiology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Wangfujing Street, Dongcheng District, Beijing 100730 (China); Jin, Zheng-Yu, E-mail: zhengyu_jin@126.com [Department of Radiology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Wangfujing Street, Dongcheng District, Beijing 100730 (China); Qian, Jia-Ming, E-mail: qjiaming57@gmail.com [Department of Gastroenterology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing (China); Yu, Jian-Chun, E-mail: yu-jch@163.com [Department of General Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing (China); Zhu, Hua-Dong, E-mail: huadongzhu@hotmail.com [Department of Emergency, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing (China)

2015-05-15

Highlights: • GIB is a common gastrointestinal emergency with a high mortality rate. • Detection and localization of GIB source are important for imaging modality. • DSDECTA using a dual-phase scan protocol is clinically feasible. • DSDECTA with VNE and iodine map images can diagnose the active GIB source accurately. • DSDECTA can reduce radiation dose compared with conventional CT examination in GIB. - Abstract: Objectives: To evaluate the clinical feasibility of dual-source dual-energy CT angiography (DSDECTA) with virtual non-enhanced images and iodine map for active gastrointestinal bleeding (GIB). Methods: From June 2010 to December 2012, 112 consecutive patients with clinical signs of active GIB underwent DSDECTA with true non-enhanced (TNE), arterial phase with single-source mode, and portal-venous phase with dual-energy mode (100 kVp/230 mAs and Sn 140 kVp/178 mAs). Virtual non-enhanced CT (VNE) image sets and iodine map were reformatted from ‘Liver VNC’ software. The mean CT number, noise, signal to noise ratio (SNR), image quality and radiation dose were compared between TNE and VNE image sets. Two radiologists, blinded to clinical data, interpreted images from DSDECTA with TNE (protocol 1), and DSDECTA with VNE and iodine map (protocol 2) respectively, with discordant interpretation resolved by consensus. The standards of reference included digital subtraction angiography, endoscopy, surgery, or final pathology reports. Receiver–operating characteristic (ROC) analysis was undertaken and the area under the curve (AUC) calculated for CT protocols 1 and 2, respectively. Results: There was no significant difference in mean CT numbers of all organs (including liver, pancreas, spleen, kidney, abdominal aorta, and psoas muscle) (P > 0.05). Lower noise and higher SNR were found on VNE images than TNE images (P < 0.05). Image quality of VNE was lower than that of TNE without significant difference (P > 0.05). The active GIB source was identified

Effect of the transverse parasitic mode on beam performance for the ADS driver linac in China

International Nuclear Information System (INIS)

Cheng Peng; Pei Shilun; Wang Jiuqing; Li Zhihui

2015-01-01

The ADS (Accelerator Driven subcritical System) driver linac in China is designed to run in CW (Continuous Wave) mode with 10 mA designed beam current. In this scenario, the beam-induced parasitic modes in the ADS driver linac may make the beam unstable or deteriorate the beam performance. To evaluate the parasitic mode effect on the beam dynamics systematically, simulation studies using the ROOT-based numerical code SMD have been conducted. The longitudinal beam instability induced by the HOMs (High Order Modes) and SOMs (Same Order Modes) has little effect on the longitudinal beam performance for the current ADS driver linac design based on the 10 MeV/325 MHz injector I from previous studies. Here the transverse parasitic mode (i.e., dipole HOM) effect on the transverse beam performance at the ADS driver linac exit is investigated. To more reasonably quantify the dipole mode effect, the multi-bunch effective emittance is introduced in this paper. (authors)

Real-time dual-band haptic music player for mobile devices.

Science.gov (United States)

Hwang, Inwook; Lee, Hyeseon; Choi, Seungmoon

2013-01-01

We introduce a novel dual-band haptic music player for real-time simultaneous vibrotactile playback with music in mobile devices. Our haptic music player features a new miniature dual-mode actuator that can produce vibrations consisting of two principal frequencies and a real-time vibration generation algorithm that can extract vibration commands from a music file for dual-band playback (bass and treble). The algorithm uses a "haptic equalizer" and provides plausible sound-to-touch modality conversion based on human perceptual data. In addition, we present a user study carried out to evaluate the subjective performance (precision, harmony, fun, and preference) of the haptic music player, in comparison with the current practice of bass-band-only vibrotactile playback via a single-frequency voice-coil actuator. The evaluation results indicated that the new dual-band playback outperforms the bass-only rendering, also providing several insights for further improvements. The developed system and experimental findings have implications for improving the multimedia experience with mobile devices.

Diagnosis value of dual-phase contrast enhancement CT combined with virtual non-enhanced images by dual-energy CT in clear cell renal cell carcinoma

International Nuclear Information System (INIS)

Ma Zhoupeng; Zhou Jianjun; Liu Xueling; Wang Chun; Zhang Shunzhuang

2012-01-01

Objective: To explore the diagnostic value of dual-phase contrast enhancement CT combined with virtual non-enhanced images by dual-energy CT in clear cell renal cell carcinoma. Methods: Sixty patients who were suspected of clear cell renal cell carcinoma underwent non-enhanced CT and contrast enhancement CT of early interface-phase between cortex -medulla and parenchymal phase on a dual-energy CT. The true non-enhanced kidney CT (TNCT) was performed in a single-energy acquisition mode, but the dual-phase contrast enhancement CT were performed in a dual-energy mode of 80 kV and 140 kV respectively. The virtual non-enhanced CT (VNCT) images were derived from the data of early interface phase using liver virtual non-contrast software. The diagnose according to VNCT combined dual-phase contrast enhancement CT and dual-phase contrast enhancement CT only were made respectively and compared with χ 2 test. Between the true non-contrast CT and the virtual non-contrast CT, the image quality was compared with Wilcoxon test; The radiation dose of volume CT dose index (CTDIvol) and dose length product(DLP) in a single-phase and total examination, the mean CT HU values of the tumours were compared with t test. Results: The accuracy of VNCT combined dual-phase contrast enhancement CT was higher than that of dual-phase contrast enhancement CT only [93.3% (56/60) vs.78.3% (47/60); χ 2 =5.6, P<0.05]. The detective ability (score) of VNCT was near to that of TNCT and the difference was not obvious (Z=0.00, P>0.05). The radiation dose of volume CT dose index (CTDIvol) and dose length product (DLP) in a single phase and total examination of VNCT [(8.85 ± 1.28) mGy, (196.45 ±21.12) mGy·cm, (17.69±2.35) mGy, (392.90±42.25) mGy · cm] were lower than that of TNCT [(10.20 ± 1.44) mGy,(218.29 ± 29.60) mGy · cm, (30.61 ± 3.27) mGy and (654.86 ± 88.81) mGy ·cm], t=4.21, 3.58, 23.63, 16.12 respectively, P<0.05. The mean CT HU values of tumours on VNCT images was higher than that

Improving Sensitivity to Detect Mild Cognitive Impairment: Cognitive Load Dual-Task Gait Speed Assessment.

Science.gov (United States)

MacAulay, Rebecca K; Wagner, Mark T; Szeles, Dana; Milano, Nicholas J

2017-07-01

Longitudinal research indicates that cognitive load dual-task gait assessment is predictive of cognitive decline and thus might provide a sensitive measure to screen for mild cognitive impairment (MCI). However, research among older adults being clinically evaluated for cognitive concerns, a defining feature of MCI, is lacking. The present study investigated the effect of performing a cognitive task on normal walking speed in patients presenting to a memory clinic with cognitive complaints. Sixty-one patients with a mean age of 68 years underwent comprehensive neuropsychological testing, clinical interview, and gait speed (simple- and dual-task conditions) assessments. Thirty-four of the 61 patients met criteria for MCI. Repeated measure analyses of covariance revealed that greater age and MCI both significantly associated with slower gait speed, pscognitive dual task within a clinically representative population. Cognitive load dual-task gait assessment may provide a cost efficient and sensitive measure to detect older adults at high risk of a dementia disorder. (JINS, 2017, 23, 493-501).

A Dual Mode Propulsion System for Small Satellite Applications

Directory of Open Access Journals (Sweden)

Kevin R. Gagne

2018-05-01

Full Text Available This study focused on the development of a chemical micropropulsion system suitable for primary propulsion and/or attitude control for a nanosatellite. Due to the limitations and expense of current micropropulsion technologies, few nanosatellites with propulsion have been launched to date; however, the availability of such a propulsion system would allow for new nanosatellite mission concepts, such as deep space exploration, maneuvering in low gravity environments and formation flying. This work describes the design of “dual mode” monopropellant/bipropellant microthruster prototype that employs a novel homogeneous catalysis scheme. Results from prototype testing are reported that validate the concept. The micropropulsion system is designed to be fabricated using a combination of additively-manufactured and commercial off the shelf (COTS parts along with non-toxic fuels, thus making it a low-cost and environmentally-friendly option for future nanosatellite missions.

Extending the Constant Power Speed Range of the Brushless DC Motor through Dual Mode Inverter Control -- Part I: Theory and Simulation

International Nuclear Information System (INIS)

Lawler, J.S.

2001-01-01

An inverter topology and control scheme has been developed that can drive low-inductance, surface-mounted permanent magnet motors over the wide constant power speed range required in electric vehicle applications. This new controller is called the dual-mode inverter control (DMIC)[1]. The DMIC can drive either the Permanent Magnet Synchronous Machine (PMSM) with sinusoidal back emf, or the brushless dc machine (BDCM) with trapezoidal emf in the motoring and regenerative braking modes. In this paper we concentrate on the BDCM under high-speed motoring conditions. Simulation results show that if all motor and inverter loss mechanisms are neglected, the constant power speed range of the DMIC is infinite. The simulation results are supported by closed form expressions for peak and rms motor current and average power derived from analytical solution to the differential equations governing the DMIC/BDCM drive for the lossless case. The analytical solution shows that the range of motor inductance that can be accommodated by the DMIC is more than an order of magnitude such that the DMIC is compatible with both low- and high-inductance BDCMs. Finally, method is given for integrating the classical hysteresis band current control, used for motor control below base speed, with the phase advance of DMIC that is applied above base speed. The power versus speed performance of the DMIC is then simulated across the entire speed range

Electroluminescence pulse shape and electron diffusion in liquid argon measured in a dual-phase TPC

Energy Technology Data Exchange (ETDEWEB)

Agnes, P.; et al.

2018-02-05

We report the measurement of the longitudinal diffusion constant in liquid argon with the DarkSide-50 dual-phase time projection chamber. The measurement is performed at drift electric fields of 100 V/cm, 150 V/cm, and 200 V/cm using high statistics $^{39}$Ar decays from atmospheric argon. We derive an expression to describe the pulse shape of the electroluminescence signal (S2) in dual-phase TPCs. The derived S2 pulse shape is fit to events from the uppermost portion of the TPC in order to characterize the radial dependence of the signal. The results are provided as inputs to the measurement of the longitudinal diffusion constant DL, which we find to be (4.12 $\\pm$ 0.04) cm$^2$/s for a selection of 140keV electron recoil events in 200V/cm drift field and 2.8kV/cm extraction field. To study the systematics of our measurement we examine datasets of varying event energy, field strength, and detector volume yielding a weighted average value for the diffusion constant of (4.09 $\\pm$ 0.09) cm$^2$ /s. The measured longitudinal diffusion constant is observed to have an energy dependence, and within the studied energy range the result is systematically lower than other results in the literature.

Individual versus Peer Grit: Influence on Later Individual Literacy Achievement of Dual Language Learners

Science.gov (United States)

O'Neal, Colleen R.

2018-01-01

The objective of this short-term longitudinal study was to examine individual versus classroom peer effects of grit on later individual literacy achievement in elementary school. The dual language learner, largely Latina/o sample included students from the 3rd through the 5th grades. Participants completed a literacy achievement performance task…

Colorimetry and SERS dual-mode detection of telomerase activity: combining rapid screening with high sensitivity.

Science.gov (United States)

Zong, Shenfei; Wang, Zhuyuan; Chen, Hui; Hu, Guohua; Liu, Min; Chen, Peng; Cui, Yiping

2014-01-01

As an important biomarker and therapeutic target, telomerase has attracted considerable attention concerning its detection and monitoring. Here, we present a colorimetry and surface enhanced Raman scattering (SERS) dual-mode telomerase activity detection method, which has several distinctive advantages. First, colorimetric functionality allows rapid preliminary discrimination of telomerase activity by the naked eye. Second, the employment of SERS technique results in greatly improved detection sensitivity. Third, the combination of colorimetry and SERS into one detection system can ensure highly efficacious and sensitive screening of numerous samples. Besides, the avoidance of polymerase chain reaction (PCR) procedures further guarantees fine reliability and simplicity. Generally, the presented method is realized by an "elongate and capture" procedure. To be specific, gold nanoparticles modified with Raman molecules and telomeric repeat complementary oligonucleotide are employed as the colorimetric-SERS bifunctional reporting nanotag, while magnetic nanoparticles functionalized with telomerase substrate oligonucleotide are used as the capturing substrate. Telomerase can synthesize and elongate telomeric repeats onto the capturing substrate. The elongated telomeric repeats subsequently facilitate capturing of the reporting nanotag via hybridization between telomeric repeat and its complementary strand. The captured nanotags can cause a significant difference in the color and SERS intensity of the magnetically separated sediments. Thus both the color and SERS can be used as indicators of the telomerase activity. With fast screening ability and outstanding sensitivity, we anticipate that this method would greatly promote practical application of telomerase-based early-stage cancer diagnosis.

Emission, efficiency, and influence in a diesel n-butanol dual-injection engine

International Nuclear Information System (INIS)

Zhu, Yanchun; Chen, Zheng; Liu, Jingping

2014-01-01

Highlights: • Dual-injection combustion for diesel n-butanol dual-fuel is investigated. • Higher EGR rate results in lower NOx and ITE, but higher smoke, HC and CO. • Larger butanol fraction results in lower smoke and ITE, but higher NOx, HC and CO. • Advanced injection can decrease smoke, HC and CO, and increase ITE. • Coupling of butanol fraction, EGR and injection timing makes for a better performance. - Abstract: In this work, a dual-injection combustion mode for diesel n-butanol dual-fuel, combined direct injection (DI) of diesel with port fuel injection (PFI) of n-butanol, was introduced. Effects of n-butanol fraction, EGR rate and injection timing on this mode were studied on a modified single-cylinder diesel engine at the speed of 1400 r/min and the IMEP of 1.0 MPa. The results indicate that with increased EGR rate, NOx emissions reduce, but smoke emissions increase. As n-butanol fraction is increased, smoke emissions decrease with a small increase in NOx. However, higher HC and CO emissions, higher indicated specific fuel consumption (ISFC) and lower indicated thermal efficiency (ITE) have to be paid with increased n-butanol fraction, especially at high EGR condition. Advancing diesel injection timing suitably has the capacity of mitigating those costs and further decreasing smoke emissions with a small penalty in NOx emissions. Coupling of large butanol fraction, high EGR rate, and advanced injection suitably contributes to a better balance between emissions and efficiency in the diesel n-butanol dual-injection engine

Micrococcus luteus mediated dual mode synthesis of gold nanoparticles: involvement of extracellular α-amylase and cell wall teichuronic acid.

Science.gov (United States)

Arunkumar, Pichaimani; Thanalakshmi, Muthukrishnan; Kumar, Priyadarsini; Premkumar, Kumpati

2013-03-01

In the present study we have utilized the bioreductive potential of Micrococcus luteus for the synthesis of gold nanoparticles. Biochemical and physiological analysis indicate that the biosynthesized GNPs were achieved by dual mode, involving extracellular α-amylase and cell wall teichuronic acid (TUA) of M. luteus. The biosynthetic potential of both α-amylase and TUA, after isolation from bacterium, was examined. Under optimum conditions, these biomolecules reduces Au(3+) into Au(0) and the resulting GNPs were found to be stable for 1 month. The synthesized GNPs were characterized by UV-VIS spectrometry, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and dynamic light scattering (DLS). Results demonstrated that the synthesized GNPs were found to be monodispersive and spherical in shape with an average size of ∼6 nm and ∼50 nm for α-amylase and teichuronic acid, respectively. These findings suggest that M. luteus can be exploited as a potential biosource for the eco-friendly synthesis of gold nanoparticles. Copyright © 2012 Elsevier B.V. All rights reserved.

On losses caused in RF cavities by longitudinal electric fields

International Nuclear Information System (INIS)

Halbritter, J.

1976-02-01

Rf modes with large longitudinal electric fields (div E vector unequal to 0) at the cavity wall systematically show worse rf properties than modes with div E vector identical with 0; e.g. enlarged rf residual losses. While magnetic residual losses R sub(res) proportional f 2 are due to uncharged inhomogeneities in the oxide coating the metal, the electric residual losses R sub(orthogonal) occur via charged states in the oxide: the recharging of those states by tunnel exchange causes excitation across the energy gap of the superconductor yielding residual losses at high rf field strengths. The interaction of E sub(orthogonal) with the charges generate (longitudinal) phonons showing up as contribution to R sub(orthogonal). The resulting R sub(orthogonal) increases with E sub(orthogonal) and is nearly independent of frequency f, indicating the importance of R sub(orthogonal) for low frequency sc cavities, especially at high field strengths. In addition R sub(orthogonal) can account for the observed large residual losses of strip line modes in narrow junctions and joints between superconductors. (orig.) [de

Customer loyalty program for the dual-energy clientele

International Nuclear Information System (INIS)

Lagace, C.

1997-01-01

Hydro-Quebec''s plans to provide a dual energy residential heating program, combining a main electric heating system and a fossil fuel back-up system, were described as an example of a customer loyalty program. It provides a portfolio of products and services answering to the different needs of customers. Dual-energy heating systems were first offered in Quebec as far back as the 1980s. Currently there are 115,000 Quebec households making use of this service. Some 35,000 of them have heat pumps and subscribe to Hydro-Quebec''s DT rate which is based on fuel mode usage being determined by exterior temperatures. The dual-energy system permits a peak-saving of some 600 MW, while maintaining electricity sales of 1,000 GWh in off-peak periods. Experiences with this system and some of the important lessons learned, especially in terms of consumer relations, were summarized. 2 refs., 1 tab

2-D modeling of dual-mode acoustic phonon excitation of a triangular nanoplate

Science.gov (United States)

Tai, Po-Tse; Yu, Pyng; Tang, Jau

2010-08-01

In this theoretical work, we investigated coherent phonon excitation of a triangular nanoplate based on 2-D Fermi-Pasta-Ulam lattice model. Based on the two-temperature model commonly used in description of laser heating of metals, we considered two kinds of forces related to electronic and lattice stresses. Based on extensive simulation and analysis, we identified two major planar phonon modes, namely, a standing wave mode related to the triangle bisector and another mode corresponding to half of the side length. This work elucidates the roles of laser-induced electronic stress and lattice stress in controlling the initial phase and the amplitude ratio between these two phonon modes.

Dual-anticipating, dual and dual-lag synchronization in modulated time-delayed systems

International Nuclear Information System (INIS)

Ghosh, Dibakar; Chowdhury, A. Roy

2010-01-01

In this Letter, dual synchronization in modulated time delay system using delay feedback controller is proposed. Based on Lyapunov stability theory, we suggest a general method to achieve the dual-anticipating, dual, dual-lag synchronization of time-delayed chaotic systems and we find both its existing and sufficient stability conditions. Numerically it is shown that the dual synchronization is also possible when driving system contain two completely different systems. Effect of parameter mismatch on dual synchronization is also discussed. As an example, numerical simulations for the Mackey-Glass and Ikeda systems are conducted, which is in good agreement with the theoretical analysis.

MPC-based energy management with adaptive Markov-chain prediction for a dual-mode hybrid electric vehicle

Institute of Scientific and Technical Information of China (English)

XIANG; ChangLe; DING; Feng; WANG; WeiDa; HE; Wei; QI; YunLong

2017-01-01

The and energy to management strategy battery is state an important part of a hybrid electrical vehicle design.It is used to improve various fuel economy sustain a proper of charge an by controlling control the power components is while satisfying to constraints and driving demands.However,achieving optimal and performance challenging due the nonlinearities of the hybrid powertrain,conflicting vehicle the time varying constraints,the dilemma capable in which controller control complexity and real-time capability are generally objectives.In this paper,a of real-time cascaded complies strategy is proposed for a dual-mode hybrid electric that considers controller based nonlinearities based the system model and with all time-varying with constraints.sampling The strategy consists of a supervisory controller on a non-linear predictive control short(MPC)sampling a long time with future strategy interval and a coordinating on linear model predictive based control with a time interval to deal different load dynamics of the system.The Additionally,a novel data methodology using adaptive Markov chains to predict demand is introduced.predictive future information is used to improve controller cycles performance.conducted.The The proposed is implemented validity on a real test-bed approach and experimental trials using economy unknown is driving are results other demonstrate the of the proposed and show that fuel significantly improved compared with methods.

MPC-based energy management with adaptive Markov-chain prediction for a dual-mode hybrid electric vehicle

Institute of Scientific and Technical Information of China (English)

XIANG ChangLe; DING Feng; WANG WeiDa; HE Wei; QI YunLong

2017-01-01

The energy management strategy is an important part of a hybrid electrical vehicle design.It is used to improve fuel economy and to sustain a proper battery state of charge by controlling the power components while satisfying various constraints and driving demands.However,achieving an optimal control performance is challenging due to the nonlinearities of the hybrid powertrain,the time varying constraints,and the dilemma in which controller complexity and real-time capability are generally conflicting objectives.In this paper,a real-time capable cascaded control strategy is proposed for a dual-mode hybrid electric vehicle that considers nonlinearities of the system and complies with all time-varying constraints.The strategy consists of a supervisory controller based on a non-linear model predictive control (MPC) with a long sampling time interval and a coordinating controller based on linear model predictive control with a short sampling time interval to deal with different dynamics of the system.Additionally,a novel data based methodology using adaptive Markov chains to predict future load demand is introduced.The predictive future information is used to improve controller performance.The proposed strategy is implemented on a real test-bed and experimental trials using unknown driving cycles are conducted.The results demonstrate the validity of the proposed approach and show that fuel economy is significantly improved compared with other methods.

Collective oscillations and coupled modes in confined microfluidic droplet arrays

Science.gov (United States)

Schiller, Ulf D.; Fleury, Jean-Baptiste; Seemann, Ralf; Gompper, Gerhard

Microfluidic droplets have a wide range of applications ranging from analytic assays in cellular biology to controlled mixing in chemical engineering. Ensembles of microfluidic droplets are interesting model systems for non-equilibrium many-body phenomena. When flowing in a microchannel, trains of droplets can form microfluidic crystals whose dynamics are governed by long-range hydrodynamic interactions and boundary effects. In this contribution, excitation mechanisms for collective waves in dense and confined microfluidic droplet arrays are investigated by experiments and computer simulations. We demonstrate that distinct modes can be excited by creating specific `defect' patterns in flowing droplet trains. While longitudinal modes exhibit a short-lived cascade of pairs of laterally displacing droplets, transversely excited modes form propagating waves that behave like microfluidic phonons. We show that the confinement induces a coupling between longitudinal and transverse modes. We also investigate the life time of the collective oscillations and discuss possible mechanisms for the onset of instabilities. Our results demonstrate that microfluidic phonons can exhibit effects beyond the linear theory, which can be studied particularly well in dense and confined systems. This work was supported by Deutsche Forschungsgemeinschaft under Grant No. SE 1118/4.

Failure mode and effects analysis in a dual-product microsphere brachytherapy environment.

Science.gov (United States)

Younge, Kelly Cooper; Lee, Choonik; Moran, Jean M; Feng, Mary; Novelli, Paula; Prisciandaro, Joann I

We performed a failure mode and effects analysis (FMEA) during the addition of a new microspheres product into our existing microsphere brachytherapy program to identify areas for safety improvements. A diverse group of team members from the microsphere program participated in the project to create a process map, identify and score failure modes, and discuss programmatic changes to address the highest ranking items. We developed custom severity ranking scales for staff- and institution-related failure modes to encompass possible risks that may exist outside of patient-based effects. Between both types of microsphere products, 173 failure mode/effect pairs were identified: 90 for patients, 35 for staff, and 48 for the institution. The SIR-Spheres program was ranked separately from the TheraSphere program because of significant differences in workflow during dose calculation, preparation, and delivery. High-ranking failure modes in each category were addressed with programmatic changes. The FMEA aided in identifying potential risk factors in our microsphere program and allowed a theoretically safer and more efficient design of the workflow and quality assurance for both our new SIR-Spheres program and our existing TheraSphere program. As new guidelines are made available, and our experience with the SIR-Spheres program increases, we will update the FMEA as an efficient starting point for future improvements. Copyright © 2016 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.

Viscose kink and drift-kink modes in a tokamak

International Nuclear Information System (INIS)

Kuvshinov, B.N.; Mikhajlovskij, A.B.

1988-01-01

Intristic kink modes in a tokamak are theoretically investigated taking account of longitudinal viscosity of ions and electrons and drift effect. It is marked that dispersion equation of investigated modes coinsides in form with that for ballooning modes. It is shown that five types of intrinsic kink instability may be distinguished in disregard of viscosity and drift effects. Effect of stabilizing quasiideal viscose kink and viscose resistive kink modes by finite Larmuir ion radius is investigated. A branch of viscose reclosure mode which instability is due to electron viscosity is pointed out. A series of other viscose and drift-kink tokamak modes is considered. Both general disperse equations of the above-mentioned kink instability varieties, taking account of viscose and drift ones, and disperse equations of separate branches are presented

Equalizer Complexity for 6-LP Mode 112 Gbit/s m-ary DP-QAM Space Division Multiplexed Transmission in Strongly Coupled Few-Mode-Fibers

DEFF Research Database (Denmark)

Asif, Rameez; Ye, Feihong; Morioka, Toshio

2015-01-01

12×12 multiple-input multiple-output (MIMO) adaptive digital signal processing (DSP). Time domain equalization (TDE) is realized to implement the linear adaptive MIMO module that is implemented in blind mode using conventional constant-modulusalgorithm (CMA) for finite impulse response (FIR) adaptive......We have quantified equalizer complexity for transmitting dual-polarized 6-LP modes (LP01, LP11a, LP11b, LP21a, LP21b and LP02) of 112 Gbit/s m-ary QAM (m=4, 16, 32, 64, 256) single carrier signals over 20 km step-index few-mode fiber. The transmitted signals are strongly coupled and recovered using...

Role of Narrative Skills on Reading Comprehension: Spanish-English and Cantonese-English Dual Language Learners

Science.gov (United States)

Uchikoshi, Yuuko; Yang, Lu; Liu, Siwei

2018-01-01

This longitudinal study examined the role of narrative skills in English reading comprehension, after controlling for vocabulary and decoding, with a sample of 112 dual language learners (DLLs), including both Spanish-English and Cantonese-English children. Decoding, vocabulary, and narrative samples were collected in the winter of first grade and…

Dual Nozzle Aerodynamic and Cooling Analysis Study.

Science.gov (United States)

1981-02-27

SSTO ) and Heavy Lift Launch Vehicle (HLLV), may embrace such capabili- ties as dual-mode operation and in-flight changes in area ratio for altitude...engines with resultant advantages. The baseline engine application, analzyed in this and earlier studies, is a tripropellant single-stage-to-orbit ( SSTO ...potential 8 1, Introduction (cont.) power cycles and generate parametric data for a tripropellant SSTO vehicle engine. A preliminary performance prediction

Concept for a LNG Gas Handling System for a Dual Fuel Engine

Directory of Open Access Journals (Sweden)

Michael Rachow

2017-09-01

Full Text Available Nowadays, ships are using LNG as main engine fuel because based on the facts that LNG has no sulphur content, and its combustion process, LNG produces low NOx content compared to heavy fuel oil and marine diesel oil. LNG is not only produces low gas emission, but may have economic advantages. In the engine laboratory of maritime studies department in Warnemunde, Germany, there is a diesel engine type MAN 6L23/30 A, where the mode operation of these engine would be changed to dual fuel engine mode operation. Therefore, in this thesis, the use dual fuel engine will be compared where it will utilize natural gas and marine diesel oil and select the required components for fuel gas supply system. By conducting the process calculation, engine MAN 6L23/30 A requires the capacity natural gas of 12.908  for 5 days at full load. A concept for LNG supply system would be arranged from storage tank until engine manifold. Germanischer Lloyd and Project Guide of dual fuel engine will be used as a guidelines to develop an optimal design and arrangement which comply with the regulation.

Horizontal-Longitudinal Correlations of Acoustic Field in Deep Water

International Nuclear Information System (INIS)

Li Jun; Li Zheng-Lin; Ren Yun; Li Wen; Zhang Ren-He

2015-01-01

The horizontal-longitudinal correlations of the acoustic field in deep water are investigated based on the experimental data obtained in the South China Sea. It is shown that the horizontal-longitudinal correlation coefficients in the convergence zone are high, and the correlation length is consistent with the convergence zone width, which depends on the receiver depth and range. The horizontal-longitudinal correlation coefficients in the convergence zone also have a division structure for the deeper receiver. The signals from the second part of the convergence zone are still correlated with the reference signal in the first part. The horizontal-longitudinal correlation coefficients in the shadow zone are lower than that in the convergence zone, and the correlation length in the shadow zone is also much shorter than that in the convergence zone. The numerical simulation results by using the normal modes theory are qualitatively consistent with the experimental results. (paper)

Measurements of urea and glucose in aqueous solutions with dual-beam near-infrared Fourier-transform spectroscopy

DEFF Research Database (Denmark)

Jensen, P.S.; Bak, J.

2002-01-01

of these two modes of operation. The concentrations of aqueous solutions of urea and glucose in the ranges 0-40 mg/dL and 0-250 mg/dL, respectively, were determined by principal component regression using both modes. The dual-beam technique eliminated instrumental variations present in the single...

Spatial relationship of 1-meter equatorial spread-F irregularities and depletions in total electron content

International Nuclear Information System (INIS)

Tsunoda, R.T.; Towle, D.M.

1979-01-01

An experiment was conducted at Kwajalein Atoll, Marshall Islands to investigate the spatial relationship of 1-m equatorial spread-F irregularities to total electron content (TEC) depletions. A high-power radar was operated (1) in a backscatter scan mode to spatially map the distribution of 1-m irregularities, and (2) in a dual-frequency, satellite-track mode to obtain the longitudinal TEC variations. We show that radar backscatter ''plumes'' found in the disturbed, nighttime equatorial ionosphere are longitudinally coincident with TEC depletions. We suggest that the TEC depletions are probably due to the presence of plasma ''bubbles'' in the equatorial F layer

Multiple dual mode counter-current chromatography with variable duration of alternating phase elution steps.

Science.gov (United States)

Kostanyan, Artak E; Erastov, Andrey A; Shishilov, Oleg N

2014-06-20

The multiple dual mode (MDM) counter-current chromatography separation processes consist of a succession of two isocratic counter-current steps and are characterized by the shuttle (forward and back) transport of the sample in chromatographic columns. In this paper, the improved MDM method based on variable duration of alternating phase elution steps has been developed and validated. The MDM separation processes with variable duration of phase elution steps are analyzed. Basing on the cell model, analytical solutions are developed for impulse and non-impulse sample loading at the beginning of the column. Using the analytical solutions, a calculation program is presented to facilitate the simulation of MDM with variable duration of phase elution steps, which can be used to select optimal process conditions for the separation of a given feed mixture. Two options of the MDM separation are analyzed: 1 - with one-step solute elution: the separation is conducted so, that the sample is transferred forward and back with upper and lower phases inside the column until the desired separation of the components is reached, and then each individual component elutes entirely within one step; 2 - with multi-step solute elution, when the fractions of individual components are collected in over several steps. It is demonstrated that proper selection of the duration of individual cycles (phase flow times) can greatly increase the separation efficiency of CCC columns. Experiments were carried out using model mixtures of compounds from the GUESSmix with solvent systems hexane/ethyl acetate/methanol/water. The experimental results are compared to the predictions of the theory. A good agreement between theory and experiment has been demonstrated. Copyright © 2014 Elsevier B.V. All rights reserved.

Simultaneous reduction of NO{sub x} and smoke in a dual fuel DI diesel engine

Energy Technology Data Exchange (ETDEWEB)

Barik, Debabrata; Murugan, S., E-mail: s.murugan@nitrkl.ac.in

2014-08-01

Highlights: • A solution to use the de-oiled cakes disposed from oil industries. • Biogas produced from Karanja de-oiled cakes contains about 73% methane. • Simultaneous reduction of NO and smoke is possible with KME–biogas dual fuel operation. • Up to 30% replacement of KME is possible with induction of biogas at 0.9 kg/h. • Improved part load performance and emission with KME–biogas dual fuel. - Abstract: This paper presents the results of an experimental investigation conducted on a compression ignition (CI) engine, modified to run on dual fuel mode, using biogas as a primary fuel and KME (Karanja methyl ester) as a pilot fuel. The biogas was produced by anaerobic digestion of Pongamia pinnata (Karanja) seed cakes. In dual fuel mode, the biogas was inducted at four different flow rates, viz. 0.3 kg/h, 0.6 kg/h, 0.9 kg/h and 1.2 kg/h through the intake manifold of the engine. The biogas flow rate of 0.9 kg/h gave a better performance and lower emissions, than those of the other flow rates. The NO and smoke emissions were found to be lower by about 34% and 14%, than those of KME operation, at full load. The ignition delay was longer by about 1–2 °CA in the dual fuel operation, than that of KME at full load. The part load performance was found to be better in dual fuel operation, with reduced emissions of NO and smoke, in comparison with KME. The ignition delay at part load in dual fuel operation was also lower than that of KME operation.

Rat Urinary Bladder Carcinogenesis by Dual-Acting PPARα+γ Agonists

Directory of Open Access Journals (Sweden)

Martin B. Oleksiewicz

2008-01-01

Full Text Available Despite clinical promise, dual-acting activators of PPARα and γ (here termed PPARα+γ agonists have experienced high attrition rates in preclinical and early clinical development, due to toxicity. In some cases, discontinuation was due to carcinogenic effect in the rat urothelium, the epithelial layer lining the urinary bladder, ureters, and kidney pelvis. Chronic pharmacological activation of PPARα is invariably associated with cancer in rats and mice. Chronic pharmacological activation of PPARγ can in some cases also cause cancer in rats and mice. Urothelial cells coexpress PPARα as well as PPARγ, making it plausible that the urothelial carcinogenicity of PPARα+γ agonists may be caused by receptor-mediated effects (exaggerated pharmacology. Based on previously published mode of action data for the PPARα+γ agonist ragaglitazar, and the available literature about the role of PPARα and γ in rodent carcinogenesis, we propose a mode of action hypothesis for the carcinogenic effect of PPARα+γ agonists in the rat urothelium, which combines receptor-mediated and off-target cytotoxic effects. The proposed mode of action hypothesis is being explored in our laboratories, towards understanding the human relevance of the rat cancer findings, and developing rapid in vitro or short-term in vivo screening approaches to faciliate development of new dual-acting PPAR agonist compounds.

Vitreous flow rates through dual pneumatic cutters: effects of duty cycle and cut rate

Directory of Open Access Journals (Sweden)

Abulon DJK

2015-02-01

Full Text Available Dina Joy K Abulon Medical Affairs, Alcon Research, Ltd, Lake Forest, CA, USA Purpose: We aimed to investigate effects of instrument settings on porcine vitreous flow rates through dual pneumatic high-speed vitrectomy probes. Methods: The CONSTELLATION® Vision System was tested with 250, 450, and 650 mmHg of vacuum using six ULTRAVIT® vitrectomy probes of each diameter (25+®, 25, 23, and 20 gauge operated from 500 cuts per minute (cpm up to 5,000 cpm. Duty cycle modes tested included biased open, 50/50, and biased closed. Flow rates were calculated by assessing the change in weight of porcine eyes during vitreous aspiration. Volumetric flow rate was measured with a computer-connected electronic scale. Results: At lower cut rates, the biased open mode produced higher flow than did the 50/50 mode, which produced higher flow than did the biased closed mode. In the biased closed and 50/50 modes, vitreous flow rates tended to increase with increasing cut rate. Vitreous flow rates in the biased open duty cycle mode remained relatively constant across cut rates. Conclusion: Vitreous flow rates through dual pneumatic vitrectomy probes could be manipulated by changing the duty cycle modes on the vitrectomy system. Differences in duty cycle behavior suggest that high-speed cut rates of 5,000 cpm may optimize vitreous aspiration. Keywords: enhanced 25-gauge vitrectomy, 25-gauge vitrectomy, 20-gauge vitrectomy, 23-gauge vitrectomy, aspiration, Constellation Vision System

Stability of longitudinal oscillations of a bunch propagating through an evacuated chamber with reactive impedance

International Nuclear Information System (INIS)

Besnier, G.

1979-01-01

The longitudinal space-charge force is assumed to vary like the derivative of the longitudinal beam density. Solutions of the linearized Vlasov equation are then given as an expansion of normal modes for the longitudinal phase-space density of a bunched beam. For a given bunch intensity, the method allows calculation of the required synchrotron frequency spread inside a parabolic bunch, in order to stabilize the beam against coherent oscillations by Landau-damping. (Auth.)

Dual Entwining Structures and Dual Entwined Modules

OpenAIRE

Abuhlail, Jawad Y.

2003-01-01

In this note we introduce and investigate the concepts of dual entwining structures and dual entwined modules. This generalizes the concepts of dual Doi-Koppinen structures and dual Doi-Koppinen modules introduced (in the infinite case over rings) by the author is his dissertation.

Low-dose computed tomography of the paranasal sinus and facial skull using a high-pitch dual-source system - First clinical results

International Nuclear Information System (INIS)

Schell, Boris; Bauer, Ralf W.; Lehnert, Thomas; Kerl, J.M.; Vogl, Thomas J.; Mack, Martin G.; Hambek, Markus; May, Angelika

2011-01-01

Computed tomography (CT) of the paranasal sinus is the standard diagnostic tool for a wide range of indications in mostly younger patients. This study aims to assess the image quality of CT of the sinus by using a high-pitch dual-source technique with special regard to the radiation dose. Examinations were performed on a second-generation dual-source CT with a pitch factor of 3.0 (dual-source mode). Images were compared with those with a pitch factor of 0.9 on the same system (single-source mode) and with those of 16-slice CT. Image quality was evaluated by four blinded readers using a 5-point scale (1 = poor, 5 = excellent). Comparison of the dose length product (DLP) was used to estimate radiation exposure. Seventy-three consecutive patients underwent imaging with the proposed CT protocols. The viewers rated the image quality of the dual-source image sets as nearly as good (3.62) as the single-source images on the same device (4.18) and those on 16-slice CT (3.7). DLP was cut to half of the dose [51 mGycm vs. 97.8 mGycm vs. 116.9 mGycm (p < 0.01)]. Using the proposed dual-source mode when examining the paranasal sinus, diagnostic image quality can be achieved while drastically lowering the patient's radiation exposure. (orig.)

High Selectivity Dual-Band Bandpass Filter with Tunable Lower Passband

Directory of Open Access Journals (Sweden)

Wei-Qiang Pan

2015-01-01

Full Text Available This paper presents a novel method to design dual-band bandpass filters with tunable lower passband and fixed upper passband. It utilizes a trimode resonator with three controllable resonant modes. Discriminating coupling is used to suppress the unwanted mode to avoid the interference. Varactors are utilized to realize tunable responses. The bandwidth of the two bands can be controlled individually. Transmission zeros are generated near the passband edges, resulting in high selectivity. For demonstration, a tunable bandpass filter is implemented. Good agreement between the prediction and measurement validates the proposed method.

Discrete mode lasers for communications applications

Science.gov (United States)

Barry, L. P.; Herbert, C.; Jones, D.; Kaszubowska-Anandarajah, A.; Kelly, B.; O'Carroll, J.; Phelan, R.; Anandarajah, P.; Shi, K.; O'Gorman, J.

2009-02-01

The wavelength spectra of ridge waveguide Fabry Perot lasers can be modified by perturbing the effective refractive index of the guided mode along very small sections of the laser cavity. One way of locally perturbing the effective index of the lasing mode is by etching features into the ridge waveguide such that each feature has a small overlap with the transverse field profile of the unperturbed mode, consequently most of the light in the laser cavity is unaffected by these perturbations. A proportion of the propagating light is however reflected at the boundaries between the perturbed and the unperturbed sections. Suitable positioning of these interfaces allows the mirror loss spectrum of a Fabry Perot laser to be manipulated. In order to achieve single longitudinal mode emission, the mirror loss of a specified mode must be reduced below that of the other cavity modes. Here we review the latest results obtained from devices containing such features. These results clearly demonstrate that these devices exceed the specifications required for a number of FTTH and Datacomms applications, such as GEPON, LX4 and CWDM. As well as this we will also present initial results on the linewidth of these devices.

Dual-keel electrodynamic maglev system

Science.gov (United States)

He, Jianliang; Wang, Zian; Rote, Donald M.; Coffey, Howard T.; Hull, John R.; Mulcahy, Thomas M.; Cal, Yigang

1996-01-01

A propulsion and stabilization system with a plurality of superconducting magnetic devices affixed to the dual-keels of a vehicle, where the superconducting magnetic devices produce a magnetic field when energized. The system also includes a plurality of figure-eight shaped null-flux coils affixed to opposing vertical sides of slots in a guideway. The figure-eight shaped null-flux coils are vertically oriented, laterally cross-connected in parallel, longitudinally connected in series, and continue the length of the vertical slots providing levitation and guidance force. An external power source energizes the figure-eight shaped null-flux coils to create a magnetic traveling wave that interacts with the magnetic field produced by the superconducting magnets to impart motion to the vehicle.

Low frequency electrostatic modes in a magnetized dusty plasma

International Nuclear Information System (INIS)

Salimullah, M.; Hassan, M.H.A.

1991-09-01

The dispersion properties of low frequency electrostatic modes in a dusty plasma in the presence of a static homogeneous magnetic field are examined. It is found that the presence of the dust particles and the static magnetic field have significant effects on the dispersion relations. For the parallel propagation the electrostatic mode is slightly modified by the magnetic field for the ion acoustic branch. A new longitudinal mode arises at the extreme low frequency limit, which is unaffected by the magnetic field for the parallel propagation. For the transverse propagation the ion acoustic mode is not affected by the magnetic field. However, the undamped extreme low frequency mode is significantly modified by the presence of the magnetic field for the propagation transverse to the direction of the magnetic field. (author). 23 refs

Dual-gated cardiac PET-clinical feasibility study

Energy Technology Data Exchange (ETDEWEB)

Teraes, Mika; Kokki, Tommi; Noponen, Tommi; Hoppela, Erika; Sipilae, Hannu T.; Knuuti, Juhani [Turku PET Centre, PO BOX 52, Turku (Finland); Durand-Schaefer, Nicolas [General Electric Medical Systems, Buc (France); Pietilae, Mikko [Turku University Hospital, Department of Internal Medicine, Turku (Finland); Kiss, Jan [Turku University Hospital, Department of Surgery, Turku (Finland)

2010-03-15

Both respiratory and cardiac motions reduce image quality in myocardial imaging. For accurate imaging of small structures such as vulnerable coronary plaques, simultaneous cardiac and respiratory gating is warranted. This study tests the feasibility of a recently developed robust method for cardiac-respiratory gating. List-mode data with triggers from respiratory and cardiac cycles are rearranged into dual-gated segments and reconstructed with standard algorithms of a commercial PET/CT scanner. Cardiac gates were defined as three fixed phases and one variable diastolic phase. Chest motion was measured with a respiratory gating device and post-processed to determine gates. Preservation of quantification in dual-gated images was tested with an IEC whole-body phantom. Minipig and human studies were performed to evaluate the feasibility of the method. In minipig studies, a coronary catheter with radioactive tip was guided in coronary artery for in vivo and ex vivo acquisitions. Dual gating in humans with suspected cardiac disorders was performed using 18-F-FDG as a tracer. The method was found feasible for in vivo imaging and the radioactive catheter tip was better resolved in gated images. In human studies, the dual gating was found feasible and easy for clinical routine. Maximal movement of myocardial surface in cranio-caudal direction was over 20 mm. The shape of myocardium was clearly different between the gates and papillary muscles become more visible in diastolic images. The first clinical experiences using robust cardiac-respiratory dual gating are encouraging. Further testing in larger clinical populations using tracers designed especially for plaque imaging is warranted. (orig.)

Dual-gated cardiac PET-clinical feasibility study

International Nuclear Information System (INIS)

Teraes, Mika; Kokki, Tommi; Noponen, Tommi; Hoppela, Erika; Sipilae, Hannu T.; Knuuti, Juhani; Durand-Schaefer, Nicolas; Pietilae, Mikko; Kiss, Jan

2010-01-01

Both respiratory and cardiac motions reduce image quality in myocardial imaging. For accurate imaging of small structures such as vulnerable coronary plaques, simultaneous cardiac and respiratory gating is warranted. This study tests the feasibility of a recently developed robust method for cardiac-respiratory gating. List-mode data with triggers from respiratory and cardiac cycles are rearranged into dual-gated segments and reconstructed with standard algorithms of a commercial PET/CT scanner. Cardiac gates were defined as three fixed phases and one variable diastolic phase. Chest motion was measured with a respiratory gating device and post-processed to determine gates. Preservation of quantification in dual-gated images was tested with an IEC whole-body phantom. Minipig and human studies were performed to evaluate the feasibility of the method. In minipig studies, a coronary catheter with radioactive tip was guided in coronary artery for in vivo and ex vivo acquisitions. Dual gating in humans with suspected cardiac disorders was performed using 18-F-FDG as a tracer. The method was found feasible for in vivo imaging and the radioactive catheter tip was better resolved in gated images. In human studies, the dual gating was found feasible and easy for clinical routine. Maximal movement of myocardial surface in cranio-caudal direction was over 20 mm. The shape of myocardium was clearly different between the gates and papillary muscles become more visible in diastolic images. The first clinical experiences using robust cardiac-respiratory dual gating are encouraging. Further testing in larger clinical populations using tracers designed especially for plaque imaging is warranted. (orig.)

CW and AO Q-switched operation of a dual-crystal Tm, Ho:GdVO4 laser pumped by two diodes

International Nuclear Information System (INIS)

Li, L J; Bai, Y F; Liu, Y W; He, Z L; Wang, J; Yao, B Q; Zhou, S; Xing, M N

2013-01-01

Continuous wave (CW) mode and acousto-optic (AO) Q-switched mode operation of a dual-crystal Tm, Ho:GdVO 4 laser is reported. The dual-crystal Tm, Ho:GdVO 4 laser with output wavelength of 2.05 μm was pumped by two laser diodes (LDs). The Tm, Ho:GdVO 4 crystals were cooled by liquid nitrogen and pumped by two fiber-coupled LDs with a center output wavelength of 801.0 nm. A 20.5 W output power was obtained at a 255 mm physical cavity length in CW mode operation, and a 19.6 W average power was obtained at a pulse repetition frequency (PRF) of 10 kHz with a 19 ns pulse duration. Also, the efficiency loss of the laser is not more than 4.4% from CW mode to Q-switch mode, and the M 2 factor, which is measured by the traveling knife-edge method, does not exceed 1.2. (paper)

Fast Interrogation of Fiber Bragg Gratings with Electro-Optical Dual Optical Frequency Combs.

Science.gov (United States)

Posada-Roman, Julio E; Garcia-Souto, Jose A; Poiana, Dragos A; Acedo, Pablo

2016-11-26

Optical frequency combs (OFC) generated by electro-optic modulation of continuous-wave lasers provide broadband coherent sources with high power per line and independent control of line spacing and the number of lines. In addition to their application in spectroscopy, they offer flexible and optimized sources for the interrogation of other sensors based on wavelength change or wavelength filtering, such as fiber Bragg grating (FBG) sensors. In this paper, a dual-OFC FBG interrogation system based on a single laser and two optical-phase modulators is presented. This architecture allows for the configuration of multimode optical source parameters such as the number of modes and their position within the reflected spectrum of the FBG. A direct read-out is obtained by mapping the optical spectrum onto the radio-frequency spectrum output of the dual-comb. This interrogation scheme is proposed for measuring fast phenomena such as vibrations and ultrasounds. Results are presented for dual-comb operation under optimized control. The optical modes are mapped onto detectable tones that are multiples of 0.5 MHz around a center radiofrequency tone (40 MHz). Measurements of ultrasounds (40 kHz and 120 kHz) are demonstrated with this sensing system. Ultrasounds induce dynamic strain onto the fiber, which generates changes in the reflected Bragg wavelength and, hence, modulates the amplitude of the OFC modes within the reflected spectrum. The amplitude modulation of two counterphase tones is detected to obtain a differential measurement proportional to the ultrasound signal.

Fast Interrogation of Fiber Bragg Gratings with Electro-Optical Dual Optical Frequency Combs

Directory of Open Access Journals (Sweden)

Julio E. Posada-Roman

2016-11-01

Full Text Available Optical frequency combs (OFC generated by electro-optic modulation of continuous-wave lasers provide broadband coherent sources with high power per line and independent control of line spacing and the number of lines. In addition to their application in spectroscopy, they offer flexible and optimized sources for the interrogation of other sensors based on wavelength change or wavelength filtering, such as fiber Bragg grating (FBG sensors. In this paper, a dual-OFC FBG interrogation system based on a single laser and two optical-phase modulators is presented. This architecture allows for the configuration of multimode optical source parameters such as the number of modes and their position within the reflected spectrum of the FBG. A direct read-out is obtained by mapping the optical spectrum onto the radio-frequency spectrum output of the dual-comb. This interrogation scheme is proposed for measuring fast phenomena such as vibrations and ultrasounds. Results are presented for dual-comb operation under optimized control. The optical modes are mapped onto detectable tones that are multiples of 0.5 MHz around a center radiofrequency tone (40 MHz. Measurements of ultrasounds (40 kHz and 120 kHz are demonstrated with this sensing system. Ultrasounds induce dynamic strain onto the fiber, which generates changes in the reflected Bragg wavelength and, hence, modulates the amplitude of the OFC modes within the reflected spectrum. The amplitude modulation of two counterphase tones is detected to obtain a differential measurement proportional to the ultrasound signal.

Effect of the high-pitch mode in dual-source computed tomography on the accuracy of three-dimensional volumetry of solid pulmonary nodules: a phantom study.

Science.gov (United States)

Hwang, Sung Ho; Oh, Yu-Whan; Ham, Soo-Youn; Kang, Eun-Young; Lee, Ki Yeol

2015-01-01

To evaluate the influence of high-pitch mode (HPM) in dual-source computed tomography (DSCT) on the accuracy of three-dimensional (3D) volumetry for solid pulmonary nodules. A lung phantom implanted with 45 solid pulmonary nodules (n = 15 for each of 4-mm, 6-mm, and 8-mm in diameter) was scanned twice, first in conventional pitch mode (CPM) and then in HPM using DSCT. The relative percentage volume errors (RPEs) of 3D volumetry were compared between the HPM and CPM. In addition, the intermode volume variability (IVV) of 3D volumetry was calculated. In the measurement of the 6-mm and 8-mm nodules, there was no significant difference in RPE (p > 0.05, respectively) between the CPM and HPM (IVVs of 1.2 ± 0.9%, and 1.7 ± 1.5%, respectively). In the measurement of the 4-mm nodules, the mean RPE in the HPM (35.1 ± 7.4%) was significantly greater (p volumetry with HPM for solid pulmonary nodule is comparable to that with CPM. However, the use of HPM may adversely affect the accuracy of 3D volumetry for smaller (< 5 mm in diameter) nodule.

Nonequilibrium atmospheric pressure plasma jet using a combination of 50 kHz/2 MHz dual-frequency power sources

International Nuclear Information System (INIS)

Zhou, Yong-Jie; Yuan, Qiang-Hua; Li, Fei; Wang, Xiao-Min; Yin, Gui-Qin; Dong, Chen-Zhong

2013-01-01

An atmospheric pressure plasma jet is generated by dual sinusoidal wave (50 kHz and 2 MHz). The dual-frequency plasma jet exhibits the advantages of both low frequency and radio frequency plasmas, namely, the long plasma plume and the high electron density. The radio frequency ignition voltage can be reduced significantly by using dual-frequency excitation compared to the conventional radio frequency without the aid of the low frequency excitation source. A larger operating range of α mode discharge can be obtained using dual-frequency excitation which is important to obtain homogeneous and low-temperature plasma. A larger controllable range of the gas temperature of atmospheric pressure plasma could also be obtained using dual-frequency excitation

Dual-mode optical microscope based on single-pixel imaging

OpenAIRE

Rodríguez Jiménez, Angel David; Clemente Pesudo, Pedro Javier; Tajahuerce, Enrique; Lancis Sáez, Jesús

2016-01-01

We demonstrate an inverted microscope that can image specimens in both reflection and transmission modes simultaneously with a single light source. The microscope utilizes a digital micromirror device (DMD) for patterned illumination altogether with two single-pixel photosensors for efficient light detection. The system, a scan-less device with no moving parts, works by sequential projection of a set of binary intensity patterns onto the sample that are codified onto a modified commercial DMD...

Reactive dual magnetron sputtering for large area application

International Nuclear Information System (INIS)

Struempfel, J.

2002-01-01

Production lines for large area coating demand high productivity of reactive magnetron sputtering processes. Increased dynamic deposition rates for oxides and nitrides were already obtained by using of highly powered magnetrons in combination with advanced sputter techniques. However, besides high deposition rates the uniformity of such coatings has to be carefully considered. First the basics of reactive sputtering processes and dual magnetron sputtering are summarized. Different methods for process stabilization and control are commonly used for reactive sputtering. The Plasma Emission Monitor (PE M) offers the prerequisite for fast acting process control derived from the in-situ intensity measurements of a spectral line of the sputtered target material. Combined by multiple Plasma Emission Monitor control loops segmented gas manifolds are able to provide excellent thin film uniformity at high deposition rates. The Dual Magnetron allows a broad range of processing by different power supply modes. Medium frequency, DC and pulsed DC power supplies can be used for high quality layers. Whereas the large area coating of highly isolating layers like TiO 2 or SiO 2 is dominated by MF sputtering best results for coating with transparent conductive oxides are obtained by dual DC powering of the dual magnetron arrangement. (Author)

Longitudinal Variation of the Lunar Tide in the Equatorial Electrojet

Science.gov (United States)

Yamazaki, Yosuke; Stolle, Claudia; Matzka, Jürgen; Siddiqui, Tarique A.; Lühr, Hermann; Alken, Patrick

2017-12-01

The atmospheric lunar tide is one known source of ionospheric variability. The subject received renewed attention as recent studies found a link between stratospheric sudden warmings and amplified lunar tidal perturbations in the equatorial ionosphere. There is increasing evidence from ground observations that the lunar tidal influence on the ionosphere depends on longitude. We use magnetic field measurements from the CHAMP satellite during July 2000 to September 2010 and from the two Swarm satellites during November 2013 to February 2017 to determine, for the first time, the complete seasonal-longitudinal climatology of the semidiurnal lunar tidal variation in the equatorial electrojet intensity. Significant longitudinal variability is found in the amplitude of the lunar tidal variation, while the longitudinal variability in the phase is small. The amplitude peaks in the Peruvian sector (˜285°E) during the Northern Hemisphere winter and equinoxes, and in the Brazilian sector (˜325°E) during the Northern Hemisphere summer. There are also local amplitude maxima at ˜55°E and ˜120°E. The longitudinal variation is partly due to the modulation of ionospheric conductivities by the inhomogeneous geomagnetic field. Another possible cause of the longitudinal variability is neutral wind forcing by nonmigrating lunar tides. A tidal spectrum analysis of the semidiurnal lunar tidal variation in the equatorial electrojet reveals the dominance of the westward propagating mode with zonal wave number 2 (SW2), with secondary contributions by westward propagating modes with zonal wave numbers 3 (SW3) and 4 (SW4). Eastward propagating waves are largely absent from the tidal spectrum. Further study will be required for the relative importance of ionospheric conductivities and nonmigrating lunar tides.

An investigation on the particulate number and size distributions over the whole engine map from an optimized combustion strategy combining RCCI and dual-fuel diesel-gasoline

International Nuclear Information System (INIS)

Benajes, Jesús; García, Antonio; Monsalve-Serrano, Javier; Boronat, Vicente

2017-01-01

Highlights: • Optimized dual-mode dual-fuel strategy to cover the whole engine map. • High coherence between smoke and total particles number for diffusive dual-fuel mode. • Fully premixed RCCI regime dominated by small particles of 30 nm diameter peak. • Highly premixed RCCI mode has a transitional behavior with two particle diameter peaks. - Abstract: Literature demonstrates that, for premixed low temperature combustion concepts, particulate matter cannot be directly extrapolated from soot emissions measurements, as typically done for conventional diesel combustion. This is because the particulate matter from low temperature combustion has low fraction of carbonaceous compounds and great amount of soluble organic fraction, which is not captured by the smoke measurement techniques such as the optical reflectometry. By this reason, the study of the particulate matter characteristics from this combustion techniques requires using specific equipment. The aim of the current work is to gain understanding on the particulate matter characteristics from the dual-mode dual-fuel combustion, which is an optimized combustion strategy that combines fully and highly premixed RCCI regimes at low and medium loads, and switches to dual-fuel diffusion combustion at full load. The study was performed over the whole engine map, using a 15.3:1 compression ratio medium-duty EURO VI diesel engine. In particular, the particulate number and size distributions were sampled using a scanning mobility particle sizer and a condensation particle counter, which allow measuring the size distribution and total number of particles from 5 to 250 nm. Results demonstrate that the fully premixed RCCI combustion is dominated by small particles (less than 30 nm in mobility diameter), the dual-fuel diffusion mode is dominated by larger particles (around 100 nm in mobility diameter) showing more diesel-like particle size distributions, and the highly premixed reactivity controlled compression

Simulation experiment on low-level RF control for dual-harmonic acceleration at CSNS RCS

International Nuclear Information System (INIS)

Shen Sirong; Li Xiao; Zhang Chunlin; Sun Hong; Tang Jingyu

2013-01-01

The design and test of the low-level RF (LLRF) control system for the dual-harmonic acceleration at the rapid cycling synchrotron (RCS) of China Spallation Neutron Source (CSNS) at phase Ⅰ is introduced. In order to implement the mode switch from the second harmonic to the fundamental during the acceleration cycle for one of the eight RF cavities, the LLRF system for the cavity has been designed differently from the others. Several technical measures such as the opening of the control loops during the mode switch and the reclosing of two tuning circuits of the RF amplifier at different moments, have been taken. The experimental results on the testing platform based on an RF prototype show good dynamic performance of the LLRF system and prove the feasibility of dual-harmonic operation. (authors)

Fiber amplifiers under thermal loads leading to transverse mode instability

DEFF Research Database (Denmark)

Johansen, Mette Marie; Hansen, Kristian Rymann; Alkeskjold, Thomas Tanggaard

2014-01-01

Transverse mode instability (TMI) in rare-earth doped fiber amplifiers operating above an average power threshold is caused by intermodal stimulated thermal Rayleigh scattering due to quantum defect heating. We investigate thermally induced longitudinal waveguide perturbations causing power...

A Priori Analysis of a Compressible Flamelet Model using RANS Data for a Dual-Mode Scramjet Combustor

Science.gov (United States)

Quinlan, Jesse R.; Drozda, Tomasz G.; McDaniel, James C.; Lacaze, Guilhem; Oefelein, Joseph

2015-01-01

In an effort to make large eddy simulation of hydrocarbon-fueled scramjet combustors more computationally accessible using realistic chemical reaction mechanisms, a compressible flamelet/progress variable (FPV) model was proposed that extends current FPV model formulations to high-speed, compressible flows. Development of this model relied on observations garnered from an a priori analysis of the Reynolds-Averaged Navier-Stokes (RANS) data obtained for the Hypersonic International Flight Research and Experimentation (HI-FiRE) dual-mode scramjet combustor. The RANS data were obtained using a reduced chemical mechanism for the combustion of a JP-7 surrogate and were validated using avail- able experimental data. These RANS data were then post-processed to obtain, in an a priori fashion, the scalar fields corresponding to an FPV-based modeling approach. In the current work, in addition to the proposed compressible flamelet model, a standard incompressible FPV model was also considered. Several candidate progress variables were investigated for their ability to recover static temperature and major and minor product species. The effects of pressure and temperature on the tabulated progress variable source term were characterized, and model coupling terms embedded in the Reynolds- averaged Navier-Stokes equations were studied. Finally, results for the novel compressible flamelet/progress variable model were presented to demonstrate the improvement attained by modeling the effects of pressure and flamelet boundary conditions on the combustion.

Perovskite photodetectors with both visible-infrared dual-mode response and super-narrowband characteristics towards photo-communication encryption application.

Science.gov (United States)

Wu, Ye; Li, Xiaoming; Wei, Yi; Gu, Yu; Zeng, Haibo

2017-12-21

Photo-communication has attracted great attention because of the rapid development of wireless information transmission technology. However, it is still a great challenge in cryptography communications, where it is greatly weakened by the openness of the light channels. Here, visible-infrared dual-mode narrowband perovskite photodetectors were fabricated and a new photo-communication encryption technique was proposed. For the first time, highly narrowband and two-photon absorption (TPA) resultant photoresponses within a single photodetector are demonstrated. The full width at half maximum (FWHM) of the photoresponse is as narrow as 13.6 nm in the visible range, which is superior to state-of-the-art narrowband photodetectors. Furthermore, these two merits of narrowband and TPA characteristics are utilized to encrypt the photo-communication based on the above photodetectors. When sending information and noise signals with 532 and 442 nm laser light simultaneously, the perovskite photodetectors only receive the main information, while the commercial Si photodetector responds to both lights, losing the main information completely. The final data are determined by the secret key through the TPA process as preset. Such narrowband and TPA detection abilities endow the perovskite photodetectors with great potential in future security communication and also provide new opportunities and platforms for encryption techniques.

Characterization of performance-emission indices of a diesel engine using ANFIS operating in dual-fuel mode with LPG

Science.gov (United States)