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1

High sensitivity charge amplifier for ion beam uniformity monitor  

DOEpatents

An ion beam uniformity monitor for very low beam currents using a high-sensitivity charge amplifier with bias compensation. The ion beam monitor is used to assess the uniformity of a raster-scanned ion beam, such as used in an ion implanter, and utilizes four Faraday cups placed in the geometric corners of the target area. Current from each cup is integrated with respect to time, thus measuring accumulated dose, or charge, in Coulombs. By comparing the dose at each corner, a qualitative assessment of ion beam uniformity is made possible. With knowledge of the relative area of the Faraday cups, the ion flux and areal dose can also be obtained.

Johnson, Gary W. (Livermore, CA)

2001-01-01

2

Charge amplifier with bias compensation  

DOEpatents

An ion beam uniformity monitor for very low beam currents using a high-sensitivity charge amplifier with bias compensation. The ion beam monitor is used to assess the uniformity of a raster-scanned ion beam, such as used in an ion implanter, and utilizes four Faraday cups placed in the geometric corners of the target area. Current from each cup is integrated with respect to time, thus measuring accumulated dose, or charge, in Coulombs. By comparing the dose at each corner, a qualitative assessment of ion beam uniformity is made possible. With knowledge of the relative area of the Faraday cups, the ion flux and areal dose can also be obtained.

Johnson, Gary W. (Livermore, CA)

2002-01-01

3

Improved charge amplifier using hybrid hysteresis compensation  

NASA Astrophysics Data System (ADS)

We present a novel charge amplifier, with a robust feedback circuit and a method for compensating piezoelectric actuator's hysteresis at low frequencies. The amplifier uses a modified feedback circuit which improves robustness to the addition of series load impedance such as in cabling. We also describe a hybrid hysteresis compensation method for enabling the charge amplifier to reduce hysteresis at low frequencies. Experimental results demonstrate the utility of the new amplifier design.

Amin-Shahidi, Darya; Trumper, David L.

2013-08-01

4

HYBRID DC ACCURATE CHARGE AMPLIFIER FOR LINEAR PIEZOELECTRIC POSITIONING  

E-print Network

HYBRID DC ACCURATE CHARGE AMPLIFIER FOR LINEAR PIEZOELECTRIC POSITIONING Andrew J. Fleming, S. O-frequency and DC operation of the amplifier. Keywords: Charge, Amplifier, Driver, Source, DC, Piezoelectric, Load 1., 2000) (Jaffe et al., 1971). When used in an actuating role, piezoelectric trans- ducers display

Fleming, Andrew J.

5

Improved current and charge amplifiers for driving piezoelectric loads  

E-print Network

generally result in the load capacitor being charged up. When the output or compliance voltage reaches to additional circuitry required to avoid charging of the capacitor. A popular technique15,16 , is to simply amplifier capable of providing high accuracy, ultra- low frequency regulation of current or charge

Fleming, Andrew J.

6

A theoretical study on stress sensitive differential amplifier (SSDA)  

E-print Network

Elsevier Ltd. All rights reserved. doi:10.1016/j.sse.2003.12.001 Solid-State Electronics 48 (2004) 715A theoretical study on stress sensitive differential amplifier (SSDA) Jingjing Li, Ruifeng Yue-sensitive differential amplifier (SSDA) is founded, connecting the stress-induced carrier mobility variation

Li, Jingjing

7

Reduction of fiber-nonlinearity-enhanced amplifier noise by means of phase-sensitive amplifiers.  

PubMed

In optical fiber transmission systems near the zero-dispersion wavelength that use in-line erbium-doped fiber amplifiers (EDFA's), the enhancement of optical amplifier noise caused by four-wave mixing (FWM) in transmission fibers degrades signal-to-noise ratio (SNR) excessively. We theoretically show that the enhancement of amplifier noise by the FWM in transmission fibers can be effectively eliminated by implementing in-line phase-sensitive amplifiers (PSA's). Small-signal analysis of the nonlinear Schrödinger equation shows that the transmission distance limited by the SNR of an in-line PSA system is expanded four times more than that of an in-line EDFA system. PMID:18183093

Imajuku, W; Takada, A

1997-01-01

8

Implementation and analysis of an innovative digital charge amplifier for hysteresis reduction in piezoelectric stack actuators  

NASA Astrophysics Data System (ADS)

Smart actuators are the key components in a variety of nanopositioning applications, such as scanning probe microscopes and atomic force microscopes. Piezoelectric actuators are the most common smart actuators due to their high resolution, low power consumption, and wide operating frequency but they suffer hysteresis which affects linearity. In this paper, an innovative digital charge amplifier is presented to reduce hysteresis in piezoelectric stack actuators. Compared to traditional analog charge drives, experimental results show that the piezoelectric stack actuator driven by the digital charge amplifier has less hysteresis. It is also shown that the voltage drop of the digital charge amplifier is significantly less than the voltage drop of conventional analog charge amplifiers.

Bazghaleh, Mohsen; Grainger, Steven; Cazzolato, Ben; Lu, Tien-Fu; Oskouei, Reza

2014-04-01

9

Implementation and analysis of an innovative digital charge amplifier for hysteresis reduction in piezoelectric stack actuators  

SciTech Connect

Smart actuators are the key components in a variety of nanopositioning applications, such as scanning probe microscopes and atomic force microscopes. Piezoelectric actuators are the most common smart actuators due to their high resolution, low power consumption, and wide operating frequency but they suffer hysteresis which affects linearity. In this paper, an innovative digital charge amplifier is presented to reduce hysteresis in piezoelectric stack actuators. Compared to traditional analog charge drives, experimental results show that the piezoelectric stack actuator driven by the digital charge amplifier has less hysteresis. It is also shown that the voltage drop of the digital charge amplifier is significantly less than the voltage drop of conventional analog charge amplifiers.

Bazghaleh, Mohsen, E-mail: mohsen.bazghaleh@adelaide.edu.au; Grainger, Steven; Cazzolato, Ben; Lu, Tien-Fu [School of Mechanical Engineering, The University of Adelaide, North Terrace, South Australia 5005 (Australia)] [School of Mechanical Engineering, The University of Adelaide, North Terrace, South Australia 5005 (Australia); Oskouei, Reza [School of Computer Science, Engineering and Mathematics, Flinders University, Bedford Park, South Australia 5042 (Australia)] [School of Computer Science, Engineering and Mathematics, Flinders University, Bedford Park, South Australia 5042 (Australia)

2014-04-15

10

An Introduction to Phase-Sensitive Amplifiers: An Inexpensive Student Instrument  

ERIC Educational Resources Information Center

Discusses the principle of operation of phase-sensitive amplifiers. Gives three examples, suitable for undergraduate laboratory use, of the use of phase-sensitive, or "lock-in" amplifiers. Concludes with a description of an inexpensive lock-in amplifier which has an overall voltage gain of 1000. (Author/MLH)

Temple, Paul A.

1975-01-01

11

A grounded-load charge amplifier for reducing hysteresis in piezoelectric tube scanners  

E-print Network

A grounded-load charge amplifier for reducing hysteresis in piezoelectric tube scanners A. J 2005 In this paper, a charge amplifier adapted for piezoelectric tube scanners is presented. Previous difficulty associated with piezoelectric tube scanners and piezoelectric actuators in general . When employed

Fleming, Andrew J.

12

Implementation and analysis of an innovative digital charge amplifier for hysteresis reduction in piezoelectric stack actuators.  

PubMed

Smart actuators are the key components in a variety of nanopositioning applications, such as scanning probe microscopes and atomic force microscopes. Piezoelectric actuators are the most common smart actuators due to their high resolution, low power consumption, and wide operating frequency but they suffer hysteresis which affects linearity. In this paper, an innovative digital charge amplifier is presented to reduce hysteresis in piezoelectric stack actuators. Compared to traditional analog charge drives, experimental results show that the piezoelectric stack actuator driven by the digital charge amplifier has less hysteresis. It is also shown that the voltage drop of the digital charge amplifier is significantly less than the voltage drop of conventional analog charge amplifiers. PMID:24784651

Bazghaleh, Mohsen; Grainger, Steven; Cazzolato, Ben; Lu, Tien-Fu; Oskouei, Reza

2014-04-01

13

Manufacturing condition optimization for optical activity enhancement on Silicon nanocluster sensitized Erbium doped waveguide amplifier  

E-print Network

for optical activity enhancement on Silicon nanocluster sensitized Erbium doped waveguide amplifier Hansuek-PON PON , , . (NC- Si EDWA: silicon nanocluster sensitized Erbium doped related to optical gain in erbium-doped silicon-rich silicon oxide waveguide amplifier," Appl. Phys. Lett

Park, Namkyoo

14

Design of a charge sensitive preamplifier on high resistivity silicon  

SciTech Connect

A low noise, fast charge sensitive preamplifier was designed on high resistivity, detector grade silicon. It is built at the surface of a fully depleted region of n-type silicon. This allows the preamplifier to be placed very close to a detector anode. The preamplifier uses the classical input cascode configuration with a capacitor and a high value resistor in the feedback loop. The output stage of the preamplifier can drive a load up to 20pF. The power dissipation of the preamplifier is 13mW. The amplifying elements are ''Single Sided Gate JFETs'' developed especially for this application. Preamplifiers connected to a low capacitance anode of a drift type detector should achieve a rise time of 20ns and have an equivalent noise charge (ENC), after a suitable shaping, of less than 50 electrons. This performance translates to a position resolution better than 3..mu..m for silicon drift detectors. 6 refs., 9 figs.

Radeka, V.; Rehak, P.; Rescia, S.; Gatti, E.; Longoni, A.; Sampietro, M.; Holl, P.; Strueder, L.; Kemmer, J.

1987-01-01

15

Improved Current and Charge Amplifiers for Driving Piezoelectric Loads, and Issues in Signal  

E-print Network

Improved Current and Charge Amplifiers for Driving Piezoelectric Loads, and Issues in Signal of hysteresis (Jaffe et al., 1971; Adriaens, 2000). When used in an actuating role, piezoelectric transducers of the sentiment towards this technique: ``While hysteresis in a piezoelectric actuator is reduced if the charge

Fleming, Andrew J.

16

A fast low noise charge preamplifier for position sensitive detectors  

NASA Astrophysics Data System (ADS)

We present the design and the results of the evaluation of a fast, low noise, charge preamplifier. This device uses commercial circuits; the advantages over classical circuits based on transistors are presented. These include short development time, high reliability and reproducibility, and easy maintenance. The amplifier has been tested with a position sensitive multiwire proportional counter with a readout system based on delay lines. With an input impedance of 50 Omega, we have obtained a signal to noise ratio better than 40 dB, a gain of 0.42 muV per electron, a pulse rise time of 9.4 ns, and a total pulse duration lower than 120 ns. These values allow detector data acquisition rates in excess of 1 MHz, and a spatial resolution better than 300 mum.

Beltran, David; Perlas, Josep Antoni

2002-08-01

17

Position Sensitive Detection System for Charged Particles  

SciTech Connect

The position sensitive detection system presented in this work employs the Anger logic algorithm to determine the position of the light spark produced by the passage of charged particles on a 170 x 170 x 10 mm3 scintillator material (PILOT-U). The detection system consists of a matrix of nine photomultipliers, covering a fraction of the back area of the scintillators. Tests made with a non-collimated alpha particle source together with a Monte Carlo simulation that reproduces the data, suggest an intrinsic position resolution of up to 6 mm is achieved.

Coello, E. A. [Instituto de Fisica, Univ. Nacional Autonoma de Mexico; Favela, F. [Instituto de Fisica, Univ. Nacional Autonoma de Mexico; Curiel, Q. [Instituto de Fisica, Univ. Nacional Autonoma de Mexico; Chavez, E [Instituto de Fisica, Univ. Nacional Autonoma de Mexico; Huerta, A. [Instituto de Fisica, Univ. Nacional Autonoma de Mexico; Varela, A. [Instituto Nacional de Investigaciones Nucleares, Ocoyoacac, Mexico; Shapira, Dan [ORNL

2012-01-01

18

Conformation sensitive charge transport in conjugated polymers  

SciTech Connect

Temperature dependent charge carrier mobility measurements using field effect transistors and density functional theory calculations are combined to show how the conformation dependent frontier orbital delocalization influences the hole- and electron mobilities in a donor-acceptor based polymer. A conformationally sensitive lowest unoccupied molecular orbital results in an electron mobility that decreases with increasing temperature above room temperature, while a conformationally stable highest occupied molecular orbital is consistent with a conventional hole mobility behavior and also proposed to be one of the reasons for why the material works well as a hole transporter in amorphous bulk heterojunction solar cells.

Mattias Andersson, L., E-mail: matan@ifm.liu.se [Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping SE-581 83 (Sweden); Hedström, Svante; Persson, Petter [Division of Theoretical Chemistry, Lund University, P.O. Box 124, SE-221 00 Lund (Sweden)] [Division of Theoretical Chemistry, Lund University, P.O. Box 124, SE-221 00 Lund (Sweden)

2013-11-18

19

Performance analysis of nanocluster-Si sensitized Er-doped waveguide amplifier using  

E-print Network

Performance analysis of nanocluster-Si sensitized Er-doped waveguide amplifier using top-pumped 470, "Optical gain at 1.54um in erbium-doped silicon nanocluster sensitized waveguide," Appl. Phys. Lett. 79 conditions for an enhanced coupling rate between Er ions and Si nanoclusters for an improved 1.54-um emission

Park, Namkyoo

20

Neutron cross section sensitivity for minor actinide transmutation in energy amplifier systems  

Microsoft Academic Search

The nuclear data sensitivity in 3D Monte Carlo burnup calculations of minor actinide transmutation in Energy Amplifier Systems is assessed. Ansaldo Nucleare’s 80MWth Energy Amplifier Demonstration Facility (EADF) design serves as a technical and geometrical platform for the analysis. The accelerator-driven EADF is a fast, subcritical system based on classical MOX-fuel technology and on molten lead–bismuth eutectic cooling. For Monte

Marcus Dahlfors; Yacine Kadi; Adonai Herrera-Martķnez

2007-01-01

21

Mass amplifying probe for sensitive fluorescence anisotropy detection of small molecules in complex biological samples.  

PubMed

Fluorescence anisotropy (FA) is a reliable and excellent choice for fluorescence sensing. One of the key factors influencing the FA value for any molecule is the molar mass of the molecule being measured. As a result, the FA method with functional nucleic acid aptamers has been limited to macromolecules such as proteins and is generally not applicable for the analysis of small molecules because their molecular masses are relatively too small to produce observable FA value changes. We report here a molecular mass amplifying strategy to construct anisotropy aptamer probes for small molecules. The probe is designed in such a way that only when a target molecule binds to the probe does it activate its binding ability to an anisotropy amplifier (a high molecular mass molecule such as protein), thus significantly increasing the molecular mass and FA value of the probe/target complex. Specifically, a mass amplifying probe (MAP) consists of a targeting aptamer domain against a target molecule and molecular mass amplifying aptamer domain for the amplifier protein. The probe is initially rendered inactive by a small blocking strand partially complementary to both target aptamer and amplifier protein aptamer so that the mass amplifying aptamer domain would not bind to the amplifier protein unless the probe has been activated by the target. In this way, we prepared two probes that constitute a target (ATP and cocaine respectively) aptamer, a thrombin (as the mass amplifier) aptamer, and a fluorophore. Both probes worked well against their corresponding small molecule targets, and the detection limits for ATP and cocaine were 0.5 ?M and 0.8 ?M, respectively. More importantly, because FA is less affected by environmental interferences, ATP in cell media and cocaine in urine were directly detected without any tedious sample pretreatment. Our results established that our molecular mass amplifying strategy can be used to design aptamer probes for rapid, sensitive, and selective detection of small molecules by means of FA in complex biological samples. PMID:22686244

Cui, Liang; Zou, Yuan; Lin, Ninghang; Zhu, Zhi; Jenkins, Gareth; Yang, Chaoyong James

2012-07-01

22

Charge structure and lightning sensitivity in a simulated multicell thunderstorm  

E-print Network

Charge structure and lightning sensitivity in a simulated multicell thunderstorm Edward R. Mansell1 continental multicell storm. Five laboratory-based parameterizations of noninductive graupel-ice charge separation are compared. Inductive (i.e., electric field-dependent) charge separation is tested

Mansell, Edward "Ted"

23

Injection locking-based pump recovery for phase-sensitive amplified links.  

PubMed

An injection locking-based pump recovery system for phase-sensitive amplified links, capable of handling 40 dB effective span loss, is demonstrated. Measurements with 10 GBd DQPSK signals show penalty-free recovery of a pump wave, phase modulated with two sinusoidal RF-tones at 0.1 GHz and 0.3 GHz, with 64 dB amplification. The operating power limit for the pump recovery system is experimentally investigated and is governed by the noise transfer and phase modulation transfer characteristics of the injection-locked laser. The corresponding link penalties are explained and quantified. This system enables, for the first time, WDM compatible phase-sensitive amplified links over significant lengths. PMID:23787639

Olsson, Samuel L I; Corcoran, Bill; Lundström, Carl; Tipsuwannakul, Ekawit; Sygletos, Stylianos; Ellis, Andrew D; Tong, Zhi; Karlsson, Magnus; Andrekson, Peter A

2013-06-17

24

Frequency-resolved noise figure measurements of phase (in)sensitive fiber optical parametric amplifiers.  

PubMed

We measure the frequency-resolved noise figure of fiber optical parametric amplifiers both in phase-insensitive and phase-sensitive modes in the frequency range from 0.03 to 3 GHz. We also measure the variation in noise figure due to the degradation in pump optical signal to noise ratio and also as a function of the input signal powers. Noise figure degradation due to stimulated Brillouin scattering is observed. PMID:25402025

Malik, R; Kumpera, A; Lorences-Riesgo, A; Andrekson, P A; Karlsson, M

2014-11-17

25

Calibration of bridge-, charge- and voltage amplifiers for dynamic measurement applications  

NASA Astrophysics Data System (ADS)

Measuring amplifiers are used for transducer output signal conditioning in many dynamic measurement applications. For a traceable measurement, a calibration of all components of the measuring chain—and therefore of the conditioning amplifiers, too—is mandatory. In this paper methods for a dynamic calibration of different types of conditioning amplifiers are presented. Measurement uncertainties and calibration results for typical amplifiers are discussed.

Klaus, Leonard; Bruns, Thomas; Volkers, Henrik

2015-02-01

26

Investigation of e-beam sensitive negative-tone chemically amplified resists for binary mask making  

NASA Astrophysics Data System (ADS)

Negative-tone chemically amplified resists MES-EN1G (JSR), FEN-270 (Fujifilm ARCH), EN-024M (TOK) and NEB-22 (Sumitomo) were evaluated for binary mask making. The investigations were performed on an advanced tool set comprising a 50kV e-beam writer Leica SB350, a Steag Hamatech hot/cool plate module APB5000, a Steag Hamatech developer ASP5000, an UNAXIS MASK ETCHER III and a SEM LEO1560 with integrated CD measurement option. We investigated and compared the evaluated resists in terms of resolution, e-beam sensitivity, resist profile, post exposure bake sensitivity, CD-uniformity, line edge roughness, pattern fidelity and etch resistance. Furthermore, the influence of post coating delay and post exposure delay in vacuum and air was determined.

Irmscher, Mathias; Berger, Lothar; Beyer, Dirk; Butschke, Joerg; Dress, Peter; Hoffmann, Thomas; Hudek, Peter; Koepernik, Corinna; Tschinkl, Martin; Voehringer, Peter

2003-08-01

27

Dual amplified electrochemical immunosensor for highly sensitive detection of Pantoea stewartii sbusp. stewartii.  

PubMed

Accurate and highly sensitive detection of Pantoea stewartii sbusp. stewartii-NCPPB 449 (PSS) is urgently required for international shipments due to tremendous agricultural economic losses. Herein, a dual amplified electrochemical sandwich immunosensor for PSS detection was developed, utilizing the good specificity and low cost of electrochemical immunoassay, the favorable conductivity and large specific surface area of gold nanoparticles (Au NPs), and the excellent catalytic ability of and horseradish peroxidase (HRP). A linear curve between current response and PSS concentration was established, and the limit of detection (LOD) was 7.8 × 10(3) cfu/mL, which is 20 times lower than that for conventional enzyme-linked immunosorbent assay (ELISA). This strategy is a useful approach for the highly sensitive detection of plant pathogenic bacterium. PMID:25384268

Zhao, Yuan; Liu, Liqiang; Kong, Dezhao; Kuang, Hua; Wang, Libing; Xu, Chuanlai

2014-12-10

28

Optimization of the alignment sensitivity and energy stability of the NIF regenerative amplifier cavity/011  

SciTech Connect

The work to improve the energy stability of the regenerative amplifier (`regen`) for the National Ignition Facility is described. This includes a fast feed-forward system, designed to regulate the output energy of the regen by monitoring how quickly a pulse builds up over many round trips. Shot-to-shot energy fluctuations of all elements prior to (and including) the regen may be compensated for in this way, at the expense of a loss of approximately 50%. Also included is a detailed study into the alignment sensitivity of the regen cavity, with the goal of quantifying the effect of misalignment on the output energy. This is done by calculating the displacement of the eigenmode by augmenting the cavity ABCD matrix with the misalignment matrix elements, E, F. In this way, cavity misalignment issues due to thermal loading of the gain medium are investigated. Alternative cavity designs, which reduce the alignment sensitivity and therefore the energy drift over periods of continuous operation, are considered. Alterations to the amplifier head design are also considered.

Hopps, N. W., Atomic Weapons Research Establishment, Aldermaston, Great Britain

1998-06-24

29

Power evolution along phase-sensitive parametric amplifiers: an experimental survey.  

PubMed

We propose and experimentally demonstrate a method based on Brillouin optical time-domain analysis to measure the longitudinal signal power distribution along phase-sensitive fiber-optical parametric amplifiers (PS-FOPAs). Experimental results show that the amplification of a PS-FOPA could go through different longitudinal profiles and yet finish with the same overall gain. This behavior is in sheer contrast with theoretical expectations, according to which longitudinal gain distribution should follow certain profiles determined by the initial relative phase difference but can never end up in the same overall gain. The gap between theory and experiment only becomes evident when the pump wavelength is within the fluctuation range of the zero dispersion wavelength (ZDW) of the PS-FOPA. PMID:25361292

Alishahi, Fatemeh; Vedadi, Armand; Shoaie, Mohammad Amin; Soto, Marcelo A; Denisov, Andrey; Mehrany, Khashayar; Thévenaz, Luc; Brčs, Camille-Sophie

2014-11-01

30

Asymmetric MQW semiconductor optical amplifier with low-polarization sensitivity of over 90-nm bandwidth  

NASA Astrophysics Data System (ADS)

An exhausted capacity of current Passive Optical Networks has been anticipated as bandwidth-hungry applications such as HDTV and 3D video become available to end-users. To enhance their performance, the next generation optical access networks have been proposed, using optical carriers allocated within the E-band (1360-1460 nm). It is partly motivated by the low-water peak fiber being manufactured by Corning. At these wavelengths, choices for low cost optical amplifiers, with compact size, low energy consumption and feasibility for integration with other optoelectronic components are limited, making the semiconductor optical amplifiers (SOA) a realistic solution. An experimental characterization of a broadband and low polarization sensitive asymmetric multi quantum well (MQW) SOA operating in the E-band is reported. The SOA device is composed of nine 6 nm In1-xGaxAsyP1-y 0.2% tensile strained asymmetric MQW layers sandwiched between nine latticed matched 6 nm InGaAsP barrier layers. The active region is grown on an n-doped InP substrate and buried by p-doped InGaAsP layers. The SOA devices have 7-degrees tilt anti-reflected coated facets, with 2 ?m ridge width, and a cavity length of 900 ?m. For input powers of -10 dBm and -20 dBm, a maximum gain of 20 dB at 1360 nm with a polarization insensitivity under 3 dB for over 90 nm bandwidth is measured. Polarization sensitivity of less than 0.5 dB is observed for some wavelengths. Obtained results indicate a promising SOA with broadband amplification, polarization insensitivity and high gain. These SOAs were designed and characterized at the Photonics Technology Laboratory, University of Ottawa, Canada.

Nkanta, Julie E.; Maldonado-Basilio, Ramón; Abdul-Majid, Sawsan; Zhang, Jessica; Hall, Trevor J.

2013-12-01

31

Charge integration successive approximation analog-to-digital converter for focal plane applications using a single amplifier  

NASA Technical Reports Server (NTRS)

An analog-to-digital converter for on-chip focal-plane image sensor applications. The analog-to-digital converter utilizes a single charge integrating amplifier in a charge balancing architecture to implement successive approximation analog-to-digital conversion. This design requires minimal chip area and has high speed and low power dissipation for operation in the 2-10 bit range. The invention is particularly well suited to CMOS on-chip applications requiring many analog-to-digital converters, such as column-parallel focal-plane architectures.

Zhou, Zhimin (Inventor); Pain, Bedabrata (Inventor)

1999-01-01

32

Electrical graphene aptasensor for ultra-sensitive detection of anthrax toxin with amplified signal transduction.  

PubMed

Detection of the anthrax toxin, the protective antigen (PA), at the attomolar (aM) level is demonstrated by an electrical aptamer sensor based on a chemically derived graphene field-effect transistor (FET) platform. Higher affinity of the aptamer probes to PA in the aptamer-immobilized FET enables significant improvements in the limit of detection (LOD), dynamic range, and sensitivity compared to the antibody-immobilized FET. Transduction signal enhancement in the aptamer FET due to an increase in captured PA molecules results in a larger 30 mV/decade shift in the charge neutrality point (Vg,min ) as a sensitivity parameter, with the dynamic range of the PA concentration between 12 aM (LOD) and 120 fM. An additional signal enhancement is obtained by the secondary aptamer-conjugated gold nanoparticles (AuNPs-aptamer), which have a sandwich structure of aptamer/PA/aptamer-AuNPs, induce an increase in charge-doping in the graphene channel, resulting in a reduction of the LOD to 1.2 aM with a three-fold increase in the Vg,min shift. PMID:23589198

Kim, Duck-Jin; Park, Hae-Chul; Sohn, Il Yung; Jung, Jin-Heak; Yoon, Ok Ja; Park, Joon-Shik; Yoon, Moon-Young; Lee, Nae-Eung

2013-10-11

33

PRC2 loss amplifies Ras-driven transcription and confers sensitivity to BRD4-based therapies.  

PubMed

The polycomb repressive complex 2 (PRC2) exerts oncogenic effects in many tumour types. However, loss-of-function mutations in PRC2 components occur in a subset of haematopoietic malignancies, suggesting that this complex plays a dichotomous and poorly understood role in cancer. Here we provide genomic, cellular, and mouse modelling data demonstrating that the polycomb group gene SUZ12 functions as tumour suppressor in PNS tumours, high-grade gliomas and melanomas by cooperating with mutations in NF1. NF1 encodes a Ras GTPase-activating protein (RasGAP) and its loss drives cancer by activating Ras. We show that SUZ12 loss potentiates the effects of NF1 mutations by amplifying Ras-driven transcription through effects on chromatin. Importantly, however, SUZ12 inactivation also triggers an epigenetic switch that sensitizes these cancers to bromodomain inhibitors. Collectively, these studies not only reveal an unexpected connection between the PRC2 complex, NF1 and Ras, but also identify a promising epigenetic-based therapeutic strategy that may be exploited for a variety of cancers. PMID:25119042

De Raedt, Thomas; Beert, Eline; Pasmant, Eric; Luscan, Armelle; Brems, Hilde; Ortonne, Nicolas; Helin, Kristian; Hornick, Jason L; Mautner, Victor; Kehrer-Sawatzki, Hildegard; Clapp, Wade; Bradner, James; Vidaud, Michel; Upadhyaya, Meena; Legius, Eric; Cichowski, Karen

2014-10-01

34

Sensitive profiling of biogenic amines in human urine by capillary electrophoresis with field amplified sample injection.  

PubMed

In order to monitor biogenic amines in human urine, a method based on field-amplified sample injection combined with capillary electrophoresis and direct UV absorption detection was developed. Dopamine, tyramine, tryptamine, serotonin and epinephrine were effectively separated and identified in human urine samples, and detection limits were 0.072, 0.010, 0.027, 0.010 and 0.120 µmol/L, respectively. Detection limits comparable to laser-induced fluorescence detection or solid phase extraction combined with capillary electrophoresis were achieved. Parameters affecting electrophoretic system detection sensitivity were investigated. Optimal separation conditions were obtained using as background electrolyte a pH 6.5 mixture of 2-(morpholino)ethanesulfonic acid 20 mmol/L and 30 mmol/L phosphate buffer, containing 0.05% hydroxypropylcellulose and 10% v/v methanol. Injections of the sample solution were performed by applying a voltage of 12 kV for 50 s. Recovery and accuracy ranged between 89.4 and 94.9%, and 89 and 112%, respectively. The method was successfully applied on actual urine samples (from a healthy volunteer): target bioamine content was consistent with endogenous levels reported in the literature. The proposed method is simple, fast and inexpensive and can be conveniently employed in work-related stress studies. The affordability and noninvasive sampling of the method allow epidemiological studies on large number of exposed persons to be performed. PMID:23529872

Bacaloni, A; Insogna, S; Sancini, A; Ciarrocca, M; Sinibaldi, F

2013-08-01

35

Noise performance of optical fiber transmission links that use non-degenerate cascaded phase-sensitive amplifiers.  

PubMed

Based on semi-classical theory, the noise performance of a multi-span fiber optical transmission system employing a cascaded phase-insensitive amplifier (PIA) and phase-sensitive amplifiers (PSAs) is investigated. Compared with the pure-PIA and pure-PSA based in-line amplification schemes, the copier + PSA scheme is found to improve the system NF by up to 6 and 3 dB, respectively, in an optimized long-haul fiber link. In addition, this cascaded configuration will significantly relax the requirement for accurate phase- and wavelength-locking which is rigorously needed in the pure-PSA configuration. This scheme is also modulation-format independent. As a proof of concept, the NF of a fiber parametric amplifier based copier + PSA cascade with inter-stage attenuation representing the fiber link is measured, which shows a 1.8-dB total NF improvement over the conventional EDFA cascade. PMID:20720922

Tong, Zhi; McKinstrie, C J; Lundström, Carl; Karlsson, Magnus; Andrekson, Peter A

2010-07-19

36

A novel charge sensitive preamplifier without the feedback resistor  

SciTech Connect

A novel charge sensitive preamplifier which has no resistor in parallel with the feedback capacitor is presented. No external device or circuit is required to discharge the feedback capacitor. The detector leakage and signal current flows away through the gate of the first JFET which works with its gate to source junction slightly forward biased. The DC stabilization of the preamplifier is accomplished by an additional feedback loop, which permits to equalize the current flowing through the forward baised gate to source junction and the current coming from the detector. An equivalent noise charge of less than 20 electrons r.m.s. has been measured at room temperature by using an input JFET with a transconductance to gate capacitance ratio of 4 mS/5.4 pF.

Bertuccio, G. (Politecnico di Milano, Milan (Italy). Dipt. di Elettronica e Informazione); Rehak, P.; Xi, D. (Brookhaven National Lab., Upton, NY (United States))

1992-01-01

37

A novel charge sensitive preamplifier without the feedback resistor  

SciTech Connect

A novel charge sensitive preamplifier which has no resistor in parallel with the feedback capacitor is presented. No external device or circuit is required to discharge the feedback capacitor. The detector leakage and signal current flows away through the gate of the first JFET which works with its gate to source junction slightly forward biased. The DC stabilization of the preamplifier is accomplished by an additional feedback loop, which permits to equalize the current flowing through the forward baised gate to source junction and the current coming from the detector. An equivalent noise charge of less than 20 electrons r.m.s. has been measured at room temperature by using an input JFET with a transconductance to gate capacitance ratio of 4 mS/5.4 pF.

Bertuccio, G. [Politecnico di Milano, Milan (Italy). Dipt. di Elettronica e Informazione; Rehak, P.; Xi, D. [Brookhaven National Lab., Upton, NY (United States)

1992-07-01

38

Sensitivity and open-loop control of stochastic response in a noise amplifier flow: the backward-facing step  

NASA Astrophysics Data System (ADS)

The two-dimensional backward-facing step flow is a canonical example of noise amplifier flow: global linear stability analysis predicts that it is stable, but perturbations can undergo large amplification in space and time as a result of non-normal effects. This amplification potential is best captured by optimal transient growth analysis, optimal harmonic forcing, or the response to sustained noise. In view of reducing disturbance amplification in these globally stable open flows, a variational technique is proposed to evaluate the sensitivity of stochastic amplification to steady control. Existing sensitivity methods are extended in two ways to achieve a realistic representation of incoming noise: (i) perturbations are time-stochastic rather than time-harmonic, (ii) perturbations are localised at the inlet rather than distributed in space. This allows for the identification of regions where small-amplitude control is the most effective, without actually computing any controlled flows. In particular, passive control by means of a small cylinder and active control by means of wall blowing/suction are analysed for Reynolds number $Re=500$ and step-to-outlet expansion ratio $\\Gamma=0.5$. Sensitivity maps for noise amplification appear largely similar to sensitivity maps for optimal harmonic amplification at the most amplified frequency. This is observed at other values of $Re$ and $\\Gamma$ too, and suggests that the design of steady control in this noise amplifier flow can be simplified by focusing on the most dangerous perturbation at the most dangerous frequency.

Boujo, E.; Gallaire, F.

2015-01-01

39

Total Charge Movement per Channel . The Relation between Gating Charge Displacement and the Voltage Sensitivity of Activation  

Microsoft Academic Search

One measure of the voltage dependence of ion channel conductance is the amount of gating charge that moves during activation and vice versa. The limiting slope method, introduced by Almers (Almers, W. 1978. Rev. Physiol. Biochem. Pharmacol. 82:96-190), exploits the relationship of charge movement and voltage sensitivity, yielding a lower limit to the range of single channel gating charge displacement.

Daniel Sigg; Francisco Bezanilla

1997-01-01

40

APPLICATIONS OF LASERS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Highly sensitive projection system with a four-wave phase-conjugating mirror and an optical quantum amplifier  

NASA Astrophysics Data System (ADS)

An investigation was made of the feasibility of reaching the quantum limit of the sensitivity of a projection system with a brightness amplifier, including a laser amplifier and a phase-conjugating mirror. A sensitivity of about 5 photons per resolution element was achieved in the near infrared (? = 1.06 ?m) when the number of elements in the field of view was ~ 350 × 350.

Kulagin, O. V.; Pasmanik, G. A.; Shilov, A. A.

1990-03-01

41

Photogeneration of charge carrier correlated with amplified spontaneous emission in single crystals of a thiophene/phenylene co-oligomer  

NASA Astrophysics Data System (ADS)

Thiophene/phenylene co-oligomers have substantial promise for the use of not only organic electronics but also organic optical devices. However, considerably less is known about the correlation between their optical and optoelectronic properties. We have investigated the charge carrier generation in 1,4-bis(5-phenylthiophen-2-yl)benzene (AC5) single crystals by flash-photolysis time-resolved microwave conductivity (TRMC) and transient absorption spectroscopy (TAS). It was found that the dependence of photocarrier generation efficiency on excitation photon density differed from that of emission efficiency once amplified spontaneous emission (ASE) and resultant spectrally narrowed emission occur upon exposure to 355 nm. In contrast, the dependences of emission and photocarrier generation efficiencies were identical when ASE was not involved at a different excitation wavelength (193 nm). An approximated analytical solution of rate equation considering ASE or singlet-singlet annihilation was applied to the experiments, exhibiting good agreement. On the basis of TRMC, TAS, and extinction coefficient of radical cation assessed by pulse radiolysis, the minimum charge carrier mobility was estimated, without electrodes, to be 0.12 cm2 V-1 s-1. The dynamics of charge carrier and triplet excited state is discussed, accompanying with examination by time-dependent density functional theory. The present work would open the way to a deeper understanding of the fate of excited state in optically robust organic semiconducting crystals.

Saeki, Akinori; Seki, Shu; Shimizu, Yasuhiro; Yamao, Takeshi; Hotta, Shu

2010-04-01

42

Sensitivity and open-loop control of stochastic response in a noise amplifier flow: the backward-facing step  

E-print Network

The two-dimensional backward-facing step flow is a canonical example of noise amplifier flow: global linear stability analysis predicts that it is stable, but perturbations can undergo large amplification in space and time as a result of non-normal effects. This amplification potential is best captured by optimal transient growth analysis, optimal harmonic forcing, or the response to sustained noise. In view of reducing disturbance amplification in these globally stable open flows, a variational technique is proposed to evaluate the sensitivity of stochastic amplification to steady control. Existing sensitivity methods are extended in two ways to achieve a realistic representation of incoming noise: (i) perturbations are time-stochastic rather than time-harmonic, (ii) perturbations are localised at the inlet rather than distributed in space. This allows for the identification of regions where small-amplitude control is the most effective, without actually computing any controlled flows. In particular, passive...

Boujo, Edouard

2014-01-01

43

Sensitive detection approaching 0.55 photon at 1064 nm using picosecond optical parametric amplifier  

NASA Astrophysics Data System (ADS)

We present experimental investigation on detection approaching 0.55 photon per pulse at 1064 nm using a 1 kHz 355-nm pumped picosecond optical parametric amplifier (OPA) with uncooled ordinary Si-CCD. The gain factor of the OPA is measured to be ~5.75×107. The ultra-weak signal detection is achieved by significant improvement of the signal-to-noise ratio (SNR) of the OPA, which is realized by suppressing the superfluorescence background utilizing long distance detection and spatial filtering in the light path, and reducing the fluctuation of total output of the OPA with large sampling number of laser shots.

Xiao, Kun; Zhang, Jing; Lin, Bin; Zhang, Qiu-lin; Zhang, Dong-xiang; Feng, Bao-hua; Zhang, Jing-yuan

2014-09-01

44

Design of Low-Noise Output Amplifiers for P-channel Charge-Coupled Devices Fabricated on High-Resistivity Silicon  

SciTech Connect

We describe the design and optimization of low-noise, single-stage output amplifiers for p-channel charge-coupled devices (CCDs) used for scientific applications in astronomy and other fields. The CCDs are fabricated on high-resistivity, 4000–5000 -cm, n-type silicon substrates. Single-stage amplifiers with different output structure designs and technologies have been characterized. The standard output amplifier is designed with an n{sup +} polysilicon gate that has a metal connection to the sense node. In an effort to lower the output amplifier readout noise by minimizing the capacitance seen at the sense node, buried-contact technology has been investigated. In this case, the output transistor has a p{sup +} polysilicon gate that connects directly to the p{sup +} sense node. Output structures with buried-contact areas as small as 2 ?m × 2 ?m are characterized. In addition, the geometry of the source-follower transistor was varied, and we report test results on the conversion gain and noise of the various amplifier structures. By use of buried-contact technology, better amplifier geometry, optimization of the amplifier biases and improvements in the test electronics design, we obtain a 45% reduction in noise, corresponding to 1.7 e{sup ?} rms at 70 kpixels/sec.

Haque, S.; Frost, F. Dion R.; Groulx, R.; Holland, S.E.; Karcher, A.; Kolbe, W.F.; Roe, N. A.; Wang, G.; Yu, Y.

2011-12-22

45

Performances of operational amplifiers in front-end electronics for nuclear radiation detectors  

Microsoft Academic Search

Operational amplifiers in charge sensitive configuration are an attractive solution for front-end electronics in cost-sensitive radiation detection systems. The noise performances of several JFET input operational amplifiers were tested in a charge-sensitive configuration. Some rather old devices reached noise performances low enough for detection of X and gamma rays in applications where extreme energy resolution is not required as, for

A. Cerizza; A. Fazzi; V. Varoli

2004-01-01

46

The Aurora kinase inhibitor CCT137690 downregulates MYCN and sensitizes MYCN-amplified neuroblastoma in vivo  

PubMed Central

The Aurora kinases regulate key stages of mitosis including centrosome maturation, spindle assembly, chromosome segregation and cytokinesis. Aurora A and B overexpression has also been associated with various human cancers and as such, they have been extensively studied as novel anti-mitotic drug targets. Here we characterise the Aurora kinase inhibitor CCT137690, a highly selective, orally bioavailable imidazo[4,5-b]pyridine derivative that inhibits Aurora A and B kinases with low nanomolar IC50 values in both biochemical and cellular assays and exhibits anti-proliferative activity against a wide range of human solid tumour cell lines. CCT137690 efficiently inhibits histone H3 and TACC3 phosphorylation (Aurora B and Aurora A substrates, respectively) in HCT116 and HeLa cells. Continuous exposure of tumour cells to the inhibitor causes multipolar spindle formation, chromosome misalignment, polyploidy and apoptosis. This is accompanied by p53/p21/BAX induction, thymidine kinase 1 (TK1) downregulation and PARP cleavage. Furthermore, CCT137690 treatment of MYCN-amplified neuroblastoma cell lines inhibits cell proliferation and decreases MYCN protein expression. Importantly, in a transgenic mouse model of neuroblastoma (TH-MYCN) that overexpresses MYCN protein and is predisposed to spontaneous neuroblastoma formation, this compound significantly inhibits tumour growth. The potent preclinical activity of CCT137690 suggests that this inhibitor may benefit patients with MYCN amplified neuroblastoma. PMID:21885865

Faisal, Amir; Vaughan, Lynsey; Bavetsias, Vassilios; Sun, Chongbo; Atrash, Butrus; Avery, Sian; Jamin, Yann; Robinson, Simon P.; Workman, Paul; Blagg, Julian; Raynaud, Florence I.; Eccles, Suzanne A.; Chesler, Louis; Linardopoulos, Spiros

2015-01-01

47

Compton amplifier  

NASA Astrophysics Data System (ADS)

An amplifier was developed for Compton detectors signals, used for the positioning of the electron beam of the linear accelerator MEA (Medium Energy Accelerator). The wire between detector and amplifier have to be about 30 m long due to radioactive radiation. The amplifier is broadband (60Hz to 2.3MHz), low noise (equivalent to 1 microA input current), and has a high common mode rejection (more than 80 dB); the inputs are galvanically separated with an input sensitivity of 1 microA. The signal to be detected is gated. Signals can be amplified to an output voltage of 5 V on 50 ohms with a 150 ms rise time.

Vanes, J. T.; Verkooijen, J. C.

1989-03-01

48

Analysis of DNA methylation of maize in response to osmotic and salt stress based on methylation-sensitive amplified polymorphism.  

PubMed

Water stress is known to alter cytosine methylation, which generally represses transcription. However, little is known about the role of methylation alteration in maize under osmotic stress. Here, methylation-sensitive amplified polymorphism (MSAP) was used to screen PEG- or NaCl-induced methylation alteration in maize seedlings. The sequences of 25 differentially amplified fragments relevant to stress were successfully obtained. Two stress-specific fragments from leaves, LP166 and LPS911, shown to be homologous to retrotransposon Gag-Pol protein genes, suggested that osmotic stress-induced methylation of retrotransposons. Three MSAP fragments, representing drought-induced or salt-induced methylation in leaves, were homologous to a maize aluminum-induced transporter. Besides these, heat shock protein HSP82, Poly [ADP-ribose] polymerase 2, Lipoxygenase, casein kinase (CK2), and dehydration-responsive element-binding (DREB) factor were also homologs of MSAP sequences from salt-treated roots. One MSAP fragment amplified from salt-treated roots, designated RS39, was homologous to the first intron of maize protein phosphatase 2C (zmPP2C), whereas - LS103, absent from salt-treated leaves, was homologous to maize glutathione S-transferases (zmGST). Expression analysis showed that salt-induced intron methylation of root zmPP2C significantly downregulated its expression, while salt-induced demethylation of leaf zmGST weakly upregulated its expression. The results suggested that salinity-induced methylation downregulated zmPP2C expression, a negative regulator of the stress response, while salinity-induced demethylation upregulated zmGST expression, a positive effecter of the stress response. Altered methylation, in response to stress, might also be involved in stress acclimation. PMID:19889550

Tan, Ming-pu

2010-01-01

49

Sensitive enantioanalysis of ?-blockers via field-amplified sample injection combined with water removal in microemulsion electrokinetic chromatography.  

PubMed

In this study, an on-line sample preconcentration technique, field-amplified sample injection combined with water removal by electroosmotic flow (EOF) pump, was applied to realize a highly sensitive chiral analysis of ?-blocker enantiomers by MEEKC. The introduction of a water plug in capillary before the electrokinetic injection provided the effective preconcentration of chiral compounds. And then the water was moving out of the column from the injection end under the effect of the EOF, which avoided dilution of the stacked ?-blocker enantiomers concentration suffering from the presence of water in separation buffer. Moreover, the addition of H3 PO4 and methanol in the sample solution greatly improved the enhancement efficiency further. Under optimized conditions, more than 2700-fold enhancement in sensitivity was obtained for each enantiomer of bupranolol (BU), alprenolol (AL), and propranolol (PRO) via electrokinetic injection. LODs were 0.10, 0.10, 0.12, 0.11, 0.02, and 0.02 ng/mL for S-BU, R-BU, S-AL, R-AL, S-PRO, and R-PRO, respectively. Eventually, the proposed method was successfully applied to the determination of BU, AL, and PRO in serum samples with good recoveries ranging from 93.4 to 98.2%. PMID:24798241

Ma, Yanhua; Zhang, Huige; Rahman, Zia Ur; Wang, Weifeng; Li, Xi; Chen, Hongli; Chen, Xingguo

2014-10-01

50

Switched-capacitor multiply-by-two amplifier with reduced capacitor mismatches sensitivity and full swing sample signal common-mode voltage  

NASA Astrophysics Data System (ADS)

A switched-capacitor amplifier with an accurate gain of two that is insensitive to component mismatch is proposed. This structure is based on associating two sets of two capacitors in cross series during the amplification phase. This circuit permits the common-mode voltage of the sample signal to reach full swing. Using the charge-complement technique, the proposed amplifier can reduce the impact of parasitic capacitors on the gain accuracy effectively. Simulation results show that as sample signal common-mode voltage changes, the difference between the minimum and maximum gain error is less than 0.03%. When the capacitor mismatch is increased from 0 to 0.2%, the gain error is deteriorated by 0.00015%. In all simulations, the gain of amplifier is 69 dB.

Xinnan, Xu; Suying, Yao; Jiangtao, Xu; Kaiming, Nie

2012-11-01

51

Burial-nutrient feedbacks amplify the sensitivity of atmospheric carbon dioxide to changes in organic matter remineralisation  

NASA Astrophysics Data System (ADS)

Changes in the marine remineralisation of particulate organic matter (POM) and calcium carbonate potentially provide a positive feedback with atmospheric CO2 and climate change. The responses to changes in remineralisation length scales are systematically mapped with the Bern3D ocean-sediment model for atmospheric CO2 and tracer fields for which observations and palaeoproxies exist. Results show that the "sediment burial-nutrient feedback" amplifies the response in atmospheric CO2 by a factor of four to seven. A transient imbalance between the weathering flux and the burial of organic matter and calcium carbonate lead to sustained changes in the ocean's phosphate and alkalinity inventory and in turn in surface nutrient availability, marine productivity, and atmospheric CO2. It takes decades to centuries to reorganise tracers and fluxes within the ocean, many millennia to approach equilibrium for burial fluxes, while ?13C signatures are still changing 200 000 years after the perturbation. At 1.7 ppm m-1, atmospheric CO2 sensitivity is about fifty times larger for a unit change in the remineralisation depth of POM than of calcium carbonate. The results highlight the role of organic matter burial in atmospheric CO2 and the substantial impacts of seemingly small changes in POM remineralisation.

Roth, R.; Ritz, S. P.; Joos, F.

2014-10-01

52

Sensitive and specific detection of Xanthomonas campestris pv. pelargonii with DNA primers and probes identified by random amplified polymorphic DNA analysis.  

PubMed Central

The random amplified polymorphic DNA method was used to distinguish strains of Xanthomonas campestris pv. pelargonii from 21 other Xanthomonas species and/or pathovars. Among the 42 arbitrarily chosen primers evaluated, 3 were found to reveal diagnostic polymorphisms when purified DNAs from compared strains were amplified by the PCR. The three primers revealed DNA amplification patterns which were conserved among all 53 strains tested of X. campestris pv. pelargonii isolated from various locations worldwide. The distinctive X. compestris pv. pelargonii patterns were clearly different from those obtained with any of 46 other Xanthomonas strains tested. An amplified 1.2-kb DNA fragment, apparently unique to X. campestris pv. pelargonii by these random amplified polymorphic DNA tests, was cloned and evaluated as a diagnostic DNA probe. It hybridized with total DNA from all 53 X. campestris pv. pelargonii strains tested and not with any of the 46 other Xanthomonas strains tested. The DNA sequence of the terminal ends of this 1.2-kb fragment was obtained and used to design a pair of 18-mer oligonucleotide primers specific for X. campestris pv. pelargonii. The custom-synthesized primers amplified the same 1.2-kb DNA fragment from all 53 X. campestris pv. pelargonii strains tested and failed to amplify DNA from any of the 46 other Xanthomonas strains tested. DNA isolated from saprophytes associated with the geranium plant also did not produce amplified DNA with these primers. The sensitivity of the PCR assay using the custom-synthesized primers was between 10 and 50 cells.(ABSTRACT TRUNCATED AT 250 WORDS) Images PMID:7993095

Manulis, S; Valinsky, L; Lichter, A; Gabriel, D W

1994-01-01

53

Method and apparatus for detection of charge on ions and particles  

DOEpatents

The present invention provides a tessellated array detector with charge collecting plate (or cup) electrode pixels and amplifying circuitry integrated into each pixel making it sensitive to external electrostatic charge; a micro collector/amplifier pixel design possessing a small capacitance to ensure a high charge to voltage signal conversion for low noise/high sensitivity operation; a micro-fabricated array of such pixels to create a useful macroscopic target area for ion and charged particle collection.

Fuerstenau, Stephen Douglas (3938 Park Pl., Montrose, CA 91020); Soli, George Arthur (4003 Wanna Vista Dr., Vancouver, WA 98661)

2002-01-01

54

Charge movement of a voltage-sensitive fluorescent protein.  

PubMed

The N-terminus of Ciona intestinalis (Ci-VSP) is a voltage-sensing domain (VSD) controlling the activity of a phosphatase domain on the C terminus. By replacing the phosphatase domain with a tandem of fluorescent proteins, CFP and YFP, a family of fluorescence resonance energy transfer-based, genetically encoded voltage-sensing fluorescent protein (VSFP) was created. VSFP2.3, one of the latest versions of this family, showed large changes in YFP emission upon changes in membrane potential with CFP excitation when expressed in Xenopus laevis oocytes. The time course of the fluorescence has two components: the fast component correlates with the time course of sensing current produced by the charge movement, while the slow component is at least one order-of-magnitude slower than the sensing current. This suggests that the tandem of fluorescent proteins reports a secondary conformational transition of the VSD which resembles the relaxation of the VSD of Ci-VSP described in detail for the Ci-VSP. This observation indicates that the relaxation of the VSD of VSFP2.3 is a global conformational change that encompasses the entire S4 segment. PMID:19167283

Villalba-Galea, Carlos A; Sandtner, Walter; Dimitrov, Dimitar; Mutoh, Hiroki; Knöpfel, Thomas; Bezanilla, Francisco

2009-01-01

55

Space-charge-dominated mass spectrometry ion sources: Modeling and sensitivity  

Microsoft Academic Search

The factors determining the sensitivity of space-charge-dominated (SCD) unipolar ion sources, such as electrospray (ESP) and\\u000a corona atmospheric pressure ionization (API) have been studied theoretically. The most important parameters are the ion density\\u000a and ion drift time in the vicinity of the sampling orifice. These are obtained by solving a system of differential equations,\\u000a “the space-charge problem.” For some simple

Mark Busman; Jan Sunner; Curtis R. Vogel

1991-01-01

56

A wide bandwidth, high linearity hybrid charge-sensitive preamplifier for high-capacitance silicon detectors  

Microsoft Academic Search

A new hybrid charge-sensitive preamplifier with a sensitivity of 5 mV\\/MeV has been specifically designed to operate in conjunction with high-capacitance silicon detectors. The shape of the leading edge of its impulse response keeps fast (20 ns) and unchanged over the full output voltage swing (7 V), as is required in nuclear-physics experiments in which Pulse-Shape Analysis is used for

Roberto Bassini; Ciro Boiano; Angelo Pagano; Alberto Pullia

2003-01-01

57

Experimental comparison of discrete and CMOS charge sensitive preamplifiers for CZT radiation detectors  

Microsoft Academic Search

During recent years, many readout integrated circuits for CdZnTe (CZT) radiation detectors have been studied particularly for use on pixellated detectors in imaging applications. The fundamental challenge is to keep noise performance similar to discrete preamplifiers, even with lower power. This paper presents an experimental evaluation of CMOS integrated charge sensitive preamplifiers intended for CZT radiation detectors using a comparison

Guillaume Montémont; Jean-Pierre Rostaing; Loļck Verger

2003-01-01

58

Enhanced Laboratory Sensitivity to Variation of the Fine-Structure Constant using Highly Charged Ions  

NASA Astrophysics Data System (ADS)

We study atomic systems that are in the frequency range of optical atomic clocks and have enhanced sensitivity to potential time variation of the fine-structure constant ?. The high sensitivity is due to coherent contributions from three factors: high nuclear charge Z, high ionization degree, and significant differences in the configuration composition of the states involved. Configuration crossing keeps the frequencies in the optical range despite the large ionization energies. We discuss a few promising examples that have the largest ? sensitivities seen in atomic systems.

Berengut, J. C.; Dzuba, V. A.; Flambaum, V. V.

2010-09-01

59

Real-space observation of unbalanced charge distribution inside a perovskite-sensitized solar cell  

NASA Astrophysics Data System (ADS)

Perovskite-sensitized solar cells have reached power conversion efficiencies comparable to commercially available solar cells used for example in solar farms. In contrast to silicon solar cells, perovskite-sensitized solar cells can be made by solution processes from inexpensive materials. The power conversion efficiency of these cells depends substantially on the charge transfer at interfaces. Here we use Kelvin probe force microscopy to study the real-space cross-sectional distribution of the internal potential within high efficiency mesoscopic methylammonium lead tri-iodide solar cells. We show that the electric field is homogeneous through these devices, similar to that of a p-i-n type junction. On illumination under short-circuit conditions, holes accumulate in front of the hole-transport layer as a consequence of unbalanced charge transport in the device. After light illumination, we find that trapped charges remain inside the active device layers. Removing these traps and the unbalanced charge injection could enable further improvements in performance of perovskite-sensitized solar cells.

Bergmann, Victor W.; Weber, Stefan A. L.; Javier Ramos, F.; Nazeeruddin, Mohammad Khaja; Grätzel, Michael; Li, Dan; Domanski, Anna L.; Lieberwirth, Ingo; Ahmad, Shahzada; Berger, Rüdiger

2014-09-01

60

Real-space observation of unbalanced charge distribution inside a perovskite-sensitized solar cell.  

PubMed

Perovskite-sensitized solar cells have reached power conversion efficiencies comparable to commercially available solar cells used for example in solar farms. In contrast to silicon solar cells, perovskite-sensitized solar cells can be made by solution processes from inexpensive materials. The power conversion efficiency of these cells depends substantially on the charge transfer at interfaces. Here we use Kelvin probe force microscopy to study the real-space cross-sectional distribution of the internal potential within high efficiency mesoscopic methylammonium lead tri-iodide solar cells. We show that the electric field is homogeneous through these devices, similar to that of a p-i-n type junction. On illumination under short-circuit conditions, holes accumulate in front of the hole-transport layer as a consequence of unbalanced charge transport in the device. After light illumination, we find that trapped charges remain inside the active device layers. Removing these traps and the unbalanced charge injection could enable further improvements in performance of perovskite-sensitized solar cells. PMID:25242041

Bergmann, Victor W; Weber, Stefan A L; Javier Ramos, F; Nazeeruddin, Mohammad Khaja; Grätzel, Michael; Li, Dan; Domanski, Anna L; Lieberwirth, Ingo; Ahmad, Shahzada; Berger, Rüdiger

2014-01-01

61

Gated charged-particle trap  

DOEpatents

The design and operation of a new type of charged-particle trap provides simultaneous measurements of mass, charge, and velocity of large electrospray ions. The trap consists of a detector tube mounted between two sets of center-bored trapping plates. Voltages applied to the trapping plates define symmetrically-opposing potential valleys which guide axially-injected ions to cycle back and forth through the charge-detection tube. A low noise charge-sensitive amplifier, connected to the tube, reproduces the image charge of individual ions as they pass through the detector tube. Ion mass is calculated from measurement of ion charge and velocity following each passage through the detector.

Benner, W. Henry (Danville, CA)

1999-01-01

62

Electronic amplifiers: A compilation  

NASA Technical Reports Server (NTRS)

Several types of amplifiers and amplifier systems are considered. These include preamplifiers, high power amplifiers, buffer and isolation amplifiers, amplifier circuits, and general purpose amplifiers.

1971-01-01

63

Sensitive analysis of amino acids and vitamin B3 in functional drinks via field-amplified stacking with reversed-field stacking in microchip electrophoresis.  

PubMed

An on-line preconcentration strategy combining field-amplified stacking and reversed-field stacking was developed for efficient and sensitive analysis of amino acids and vitamin B3 including lysine (Lys), taurine (Tau), and niacinamide (NA) by microchip electrophoresis with LIF detection. In this technique, the addition of a reversed-polarity step termed reversed-field stacking could enhance the preconcentration effect of field-amplified stacking and push most of the sample matrix out of the separation channel, thus greatly improving the sensitivity enhancement by 1-2 orders of magnitude over the classical MCE-LIF methods. The related mechanism as well as important parameters governing preconcentration and separation have been investigated in order to obtain strongest sensitivity amplification and maximum resolution. Under optimal conditions, all analytes were successfully focused and completely separated within 4 min. The limits of detection for Lys, Tau, and NA were 0.25, 0.50, and 0.20 nM (S/N=3), respectively, and enhancement factors of 165-, 285-, and 236-fold were obtained for Lys, Tau, and NA as compared to using the no concentration step. Other validation parameters such as linearity and precision were considered as satisfactory. The proposed method also gave accurate and reliable results in the analysis of these functional ingredients in eight functional drink samples. PMID:25281150

Wu, Minglei; Gao, Fan; Zhang, Yi; Wang, Qingjiang; Li, Hui

2015-01-01

64

Relationship between Resolution, Line Edge Roughness, and Sensitivity in Chemically Amplified Resist of Post-Optical Lithography Revealed by Monte Carlo and Dissolution Simulations  

NASA Astrophysics Data System (ADS)

The simultaneous achievement of high resolution and low line width (edge) roughness (LWR, LER) at acceptable sensitivity (RLS) in chemically-amplified resist (CAR) is in strong demand to realize the mass production of ultra-small electric circuit using extreme ultraviolet. We performed Monte Carlo and dissolution simulations of positive-tone CAR of electron beam lithography to clarify this RLS formation. The trade-off RLS relationship was successfully reproduced and discussed in terms of non-scaling law of exposed line width. It was demonstrated that LER follows the inverse of square root of exposure dose at moderate acid diffusion length.

Saeki, Akinori; Kozawa, Takahiro; Tagawa, Seiichi

2009-07-01

65

Development of Charge Sensitive Infrared Phototransistors for the Far-Infrared Wavelength  

NASA Astrophysics Data System (ADS)

Ultra-highly-sensitive far-infrared detectors are developed for potential application to astronomy. The detectors exploit a novel mechanism called Charge Sensitive Infrared Phototransistors (CSIPs), in which an upper quantum well (QW) in GaAs/AlGaAs double QW structures is positively charged up by photo-excitation via inter-subband transition. This causes the conductance of the lower QW channel to increase. The device is effectively a phototransistor, in which the upper QW serves as a photo-sensitive gate to the source-drain channel provided by the lower QW. Resultant extraordinary high photoconductive gain makes CSIPs so sensitive as to detect single photons. CSIPs are well established in the mid-infrared ( = 12-20 m), achieving noise equivalent power around 1.9 10 W/Hz with a quantum efficiency of 7 %. CSIPs have been demonstrated to work in longer wavelengths up to 45 m, but the sensitivity was not as high as in the shorter wavelengths, probably due to lower quantum efficiency. Reported here is a remarkable improvement in the performance of longer wavelength CSIPs (45 m), achieved primarily by optimizing the doping concentration in the upper QW. This work indicates that longer wavelength CSIPs are promising detectors for the astronomical application.

Nihei, R.; Komiyama, S.; Kawada, M.; Matsuura, S.; Doi, Y.; Satoh, T.; Nakagawa, T.

2014-08-01

66

Quantum squeezing and entanglement from a two-mode phase-sensitive amplifier via four-wave mixing in rubidium vapor  

NASA Astrophysics Data System (ADS)

Phase-sensitive amplifiers (PSAs) have been widely studied in fiber amplifiers, with remarkable recent advances. They have also been implemented in an SU(1,1) interferometer. In this paper, we study an experimental scheme for the implementation of a two-mode PSA based on a four-wave mixing process in rubidium vapor. With the process seeded by coherent probe and conjugate beams, quantum correlation including intensity difference/sum squeezing and quadrature entanglement between the output probe and conjugate fields are theoretically analyzed. Compared to previous related research, several new and interesting results are reported here. The maximal degree of intensity difference squeezing can be enhanced by nearly 3 dB compared to a phase-insensitive amplifier with the same gain. It is also possible to generate intensity sum squeezing between the probe and conjugate fields by choosing the specific phase of the input beams. Moreover, quadrature entanglement between the probe and conjugate beams, which can be manipulated by the phase of the input beams, is predicted. Our scheme may find a variety of applications in quantum metrology and quantum information processing owing to its ability of quantum squeezing and entanglement manipulation.

Fang, Yami; Jing, Jietai

2015-02-01

67

Charge generation by heavy ions in power MOSFETs, burnout space predictions, and dynamic SEB sensitivity  

NASA Technical Reports Server (NTRS)

The transport, energy loss, and charge production of heavy ions in the sensitive regions of IRF 150 power MOSFETs are described. The dependence and variation of transport parameters with ion type and energy relative to the requirements for single event burnout in this part type are discussed. Test data taken with this power MOSFET are used together with analyses by means of a computer code of the ion energy loss and charge production in the device to establish criteria for burnout and parameters for space predictions. These parameters are then used in an application to predict burnout rates in a geostationary orbit for power converters operating in a dynamic mode. Comparisons of rates for different geometries in simulating SEU (single event upset) sensitive volumes are presented.

Stassinopoulos, E. G.; Brucker, G. J.; Calvel, P.; Baiget, A.; Peyrotte, C.; Gaillard, R.

1992-01-01

68

Factors limiting the sensitivity and dynamic range of a seismic system employing analog magnetic tape recording and a seismic amplifier with adjustable gain settings and several output levels  

USGS Publications Warehouse

In the course of modernizing the low-speed-tape-recorder portable seismic systems and considering the possibilities for the design of a cassette-tape-recorder seismic refraction system, the factors that limit the sensitivity and dynamic range of such systems have been reviewed. These factors will first be stated briefly, and then their influence on systems such as the new 5-day-tape seismic system will be examined in more detail. To fix ideas, we shall assume that the system consists of the following elements: 1. A seismic sensor: usually a moving coil inertial seismometer with a period of about 1 second, a coil resistance of about 5000 ohms, and an effective motor constant of 1.0 V/cm/sec (across a 10K load terminating the seismometer sensitivity-and-damping-adjustment resistive network). 2. A seismic amplifier/voltage controlled oscillator unit made up of the following components: a) A fixed gain preamplifier with an input resistance of 10K and an internal noise level of 0.5 muVpp referred to the preamp input (0.1 Hz <= freq. <= 30 hz). b) An adjustable gain (0 to 42 db in 6 db steps) intermediate amplifier c) One or more fixed gain output amplifiers. d) Two sections of 6 db/octave bandpass filter serving to couple the 3 amplifier stages together. e) Voltage controlled oscillators for each output amplifier to produce modulated FM carriers for recording on separate tape tracks or modulated FM subcarriers for subsequent multiplexing and direct recording on tape in the California Network format. 3. An analog magnetic tape recorder: e.g. the PI 5100 (15/80 ips recording in the FM mode or in the direct mode with the 'broad-band' variant-of the Cal Net multiplex system, or 15/16 ips recording in the direct mode with the standard Cal Net multiplex system), or the Sony TC-126 cassette recorder operating in the direct record mode with the standard Cal Net multiplex system. 4. Appropriate magnetic tape playback equipment: e.g., the Bell and Howell 3700-B for the PI-5100 or the Sony TC 126 for its own tapes. 5. Appropriate discriminators (employing subtractive compensation, at least for the multiplexed systems) to restore the data signals to their original forms. 6. An A/D convertor to digitize the seismic signals for computer processing and/or a strip chart recorder (e.g., the Siemens Oscillomink) for playout of the data.

Eaton, Jerry P.; Van Schaack, John R.

1977-01-01

69

A new mussel-inspired polydopamine sensitizer for dye-sensitized solar cells: controlled synthesis and charge transfer.  

PubMed

The efficient electron injection by direct dye-to-TiO(2) charge transfer and strong adhesion of mussel-inspired synthetic polydopamine (PDA) dyes with TiO(2) electrode is demonstrated. Spontaneous self-polymerization of dopamine using dip-coating (DC) and cyclic voltammetry (CV) in basic buffer solution were applied to TiO(2) layers under a nitrogen atmosphere, which offers a facile and reliable synthetic pathway to make the PDA dyes, PDA-DC and PDA-CV, with conformal surface and perform an efficient dye-to-TiO(2) charge transfer. Both synthetic methods led to excellent photovoltaic results and the PDA-DC dye exhibited larger current density and efficiency values than those in the PDA-CV dye. Under simulated AM 1.5?G solar light (100 mW cm(-2)), a PDA-DC dye exhibited a short circuit current density of 5.50 mW cm(-2), corresponding to an overall power conversion efficiency of 1.2 %, which is almost 10 times that of the dopamine dye-sensitized solar cell. The PDA dyes showed strong adhesion with the nanocrystalline TiO(2) electrodes and the interface engineering of a dye-adsorbed TiO(2) surface through the control of the coating methods, reaction times and solution concentration maximized the overall conversion efficiency, resulting in a remarkably high efficiency. PMID:23001762

Nam, Hye Jin; Kim, Boeun; Ko, Min Jae; Jin, Mingshi; Kim, Ji Man; Jung, Duk-Young

2012-10-29

70

Highly stable biased amplifier and stretcher system  

NASA Technical Reports Server (NTRS)

Amplifier and stretcher system, which minimizes thermal effects and compensates for repetition-rate effects, maintains resolution levels in spectrum analysis. An additional inverting amplifier is used in the system to provide a noiseless charge restorer.

Roddick, R. G.

1970-01-01

71

Energy-sensitive X-ray radiography and charge sharing effect in pixelated detector  

NASA Astrophysics Data System (ADS)

The semiconductor pixel detector TimePix (256×256 pixels with a pitch of 55 ?m) is a newly developed successor of the Medipix2 device. Each Timepix pixel can be operated in Time-over-Threshold mode allowing direct energy measurement. The possibility of per pixel energy measurement presents a substantial advantage for X-ray radiography with polychromatic X-ray sources (tubes) allowing material identification (colour X-ray radiography) via analysis of transmission energy spectra. The energy resolution of the pixelated planar detector is, however, influenced by charge sharing. The ionization charge generated by the particle (X-ray photon) can be collected by several pixels, forming a cluster. If the fraction of the charge collected by a particular pixel drops below the energy threshold it is not counted and therefore it is lost. This fact, together with the presence of noise, limits the energy resolution of the device. A simplified model of the charge sharing effect is studied in this work and compared with experimental data. The application of a (per-pixel) energy-calibrated TimePix detector in the field of energy-sensitive X-ray radiography enables the recognition of soft biological materials (fat and muscle tissue) which is presented here.

Jakubek, Jan

2009-08-01

72

Charge transport through split photoelectrodes in dye-sensitized solar cells  

SciTech Connect

Charge transport and recombination are relatively ignored parameters while upscaling dye-sensitized solar cells (DSCs). Enhanced photovoltaic parameters are anticipated by merely widening the devices physical dimensions, viz., thickness and area as evident from the device design adopted in reported large area DSCs. These strip designs lead to ?50% loss in photocurrent compared to the high efficiency lab scale devices. Herein, we report that the key to achieving higher current density (J{sub SC}) is optimized diffusion volume rather than the increased photoelectrode area because kinetics of the devices is strongly influenced by the varied choices of diffusion pathways upon increasing the electrode area. For a given electrode area and thickness, we altered the photoelectrode design by splitting the electrode into multiple fractions to restrict the electron diffusion pathways. We observed a correlation between the device physical dimensions and its charge collection efficiency via current-voltage and impedance spectroscopy measurements. The modified electrode designs showed >50% increased J{sub SC} due to shorter transport time, higher recombination resistance and enhanced charge collection efficiency compared to the conventional ones despite their similar active volume (?3.36?×?10{sup ?4}?cm{sup 3}). A detailed charge transport characteristic of the split devices and their comparison with single electrode configuration is described in this article.

Fakharuddin, Azhar; Ahmed, Irfan; Yusoff, Mashitah M.; Jose, Rajan, E-mail: rjose@ump.edu.my [Nanostructured Renewable Energy Materials Laboratory, Faculty of Industrial Sciences and Technology, Universiti Malaysia Pahang, Kuantan 26300 (Malaysia); Khalidin, Zulkeflee [Faculty of Electrical and Electronics Engineering, Universiti Malaysia Pahang, Kuantan 26600 (Malaysia)

2014-04-28

73

Visualizing interfacial charge transfer in dye sensitized nanoparticles using x-ray transient absorption spectroscopy.  

SciTech Connect

A molecular level understanding of the structural reorganization accompanying interfacial electron transfer is important for rational design of solar cells. Here we have applied XTA (X-ray transient absorption) spectroscopy to study transient structures in a heterogeneous interfacial system mimicking the charge separation process in dye-sensitized solar cell (DSSC) with Ru(dcbpy){sub 2}(NCS){sub 2} (RuN3) dye adsorbed to TiO{sub 2} nanoparticle surfaces. The results show that the average Ru-NCS bond length reduces by 0.06 {angstrom}, whereas the average Ru-N(dcbpy) bond length remains nearly unchanged after the electron injection. The differences in bond-order change and steric hindrance between two types of ligands are attributed to their structural response in the charge separation. This study extends the application of XTA into optically opaque hybrid interfacial systems relevant to the solar energy conversion.

Zhang, X. Y.; Smolentsev, G.; Guo, J.; Attenkofer, K.; Kurtz, C.; Jennings, G.; Lockard, J. V.; Stickrath, A. B.; Chen, L. X. (X-Ray Science Division); (Southern Federal Univ.); (Lund Univ.); (Northwestern Univ.)

2011-01-01

74

Boosting the efficiency of quantum dot sensitized solar cells through modulation of interfacial charge transfer.  

PubMed

The demand for clean energy will require the design of nanostructure-based light-harvesting assemblies for the conversion of solar energy into chemical energy (solar fuels) and electrical energy (solar cells). Semiconductor nanocrystals serve as the building blocks for designing next generation solar cells, and metal chalcogenides (e.g., CdS, CdSe, PbS, and PbSe) are particularly useful for harnessing size-dependent optical and electronic properties in these nanostructures. This Account focuses on photoinduced electron transfer processes in quantum dot sensitized solar cells (QDSCs) and discusses strategies to overcome the limitations of various interfacial electron transfer processes. The heterojunction of two semiconductor nanocrystals with matched band energies (e.g., TiO(2) and CdSe) facilitates charge separation. The rate at which these separated charge carriers are driven toward opposing electrodes is a major factor that dictates the overall photocurrent generation efficiency. The hole transfer at the semiconductor remains a major bottleneck in QDSCs. For example, the rate constant for hole transfer is 2-3 orders of magnitude lower than the electron injection from excited CdSe into oxide (e.g., TiO(2)) semiconductor. Disparity between the electron and hole scavenging rate leads to further accumulation of holes within the CdSe QD and increases the rate of electron-hole recombination. To overcome the losses due to charge recombination processes at the interface, researchers need to accelerate electron and hole transport. The power conversion efficiency for liquid junction and solid state quantum dot solar cells, which is in the range of 5-6%, represents a significant advance toward effective utilization of nanomaterials for solar cells. The design of new semiconductor architectures could address many of the issues related to modulation of various charge transfer steps. With the resolution of those problems, the efficiencies of QDSCs could approach those of dye sensitized solar cells (DSSC) and organic photovoltaics. PMID:22493938

Kamat, Prashant V

2012-11-20

75

Ion induced charge collection and SEU sensitivity of emitter coupled logic (ECL) devices  

SciTech Connect

This paper presents single event upset (SEU) and latchup test results for selected Emitter Coupled Logic (ECL) microcircuits, including several types of low capacity SRAMs and other memory devices. The high speed of ECL memory devices makes them attractive for use in space applications. However, the emitter coupled transistor design increases susceptibility to radiation induced functional errors, especially SEU, because the transistors are not saturated, unlike the transistors in a CMOS device. Charge collection at the sensitive nodes in ECL memory elements differs accordingly. These differences are responsible, in part, for the heightened SEU vulnerability of ECL memory devices relative to their CMOS counterparts.

Koga, R.; Crain, W.R.; Hansel, S.J.; Crawford, K.B.; Kirshman, J.F.; Pinkerton, S.D.; Penzin, S.H.; Moss, S.C. [Aerospace Corp., El Segundo, CA (United States)] [Aerospace Corp., El Segundo, CA (United States); Maher, M. [National Semiconductor, South Portland, ME (United States)] [National Semiconductor, South Portland, ME (United States)

1995-12-01

76

Photoinduced charge transfer and acetone sensitivity of single-walled carbon nanotube-titanium dioxide hybrids.  

PubMed

The unique physical and chemical properties of single-walled carbon nanotubes (SWNTs) make them ideal building blocks for the construction of hybrid nanostructures. In addition to increasing the material complexity and functionality, SWNTs can probe the interfacial processes in the hybrid system. In this work, SWNT-TiO2 core/shell hybrid nanostructures were found to exhibit unique electrical behavior in response to UV illumination and acetone vapors. By experimental and theoretical studies of UV and acetone sensitivities of different SWNT-TiO2 hybrid systems, we established a fundamental understanding on the interfacial charge transfer between photoexcited TiO2 and SWNTs as well as the mechanism of acetone sensing. We further demonstrated a practical application of photoinduced acetone sensitivity by fabricating a microsized room temperature acetone sensor that showed fast, linear, and reversible detection of acetone vapors with concentrations in few parts per million range. PMID:23734594

Ding, Mengning; Sorescu, Dan C; Star, Alexander

2013-06-19

77

DNA methylation levels analysis in four tissues of sea cucumber Apostichopus japonicus based on fluorescence-labeled methylation-sensitive amplified polymorphism (F-MSAP) during aestivation.  

PubMed

DNA methylation plays an important role in regulating transcriptional change in response to environmental stimuli. In the present study, DNA methylation levels of tissues of the sea cucumber Apostichopus japonicus were analyzed by the fluorescence-labeled methylation-sensitive amplified polymorphism (F-MSAP) technique over three stages of the aestivation cycle. Overall, a total of 26,963 fragments were amplified including 9112 methylated fragments among four sea cucumber tissues using 18 pairs of selective primers. Results indicated an average DNA methylation level of 33.79% for A. japonicus. The incidence of DNA methylation was different across tissue types in the non-aestivation stage: intestine (30.16%), respiratory tree (27.61%), muscle (27.94%) and body wall (56.25%). Our results show that hypermethylation accompanied deep-aestivation in A. japonicus, which suggests that DNA methylation may have an important role in regulating global transcriptional suppression during aestivation. Further analysis indicated that the main DNA modification sites were focused on intestine and respiratory tree tissues and that full-methylation but not hemi-methylation levels exhibited significant increases in the deep-aestivation stage. PMID:25461675

Zhao, Ye; Chen, Muyan; Storey, Kenneth B; Sun, Lina; Yang, Hongsheng

2015-03-01

78

A convenient and sensitive method for haloacetic acid analysis in tap water by on-line field-amplified sample-stacking CE-ESI-MS.  

PubMed

In this study, we propose a simple strategy based on flow injection and field-amplified sample-stacking CE-ESI-MS/MS to analyze haloacetic acids (HAAs) in tap water. Tap water was passed through a desalination cartridge before field-amplified sample-stacking CE-ESI-MS/MS analysis to reduce sample salinity. With this treatment, the signals of the HAAs increased 300- to 1400-fold. The LODs for tap water analysis were in the range of 10 to 100 ng/L, except for the LOD of monochloroacetic acid (1 ?g/L in selected-ion monitoring mode detection). The proposed method is fast, convenient, and sensitive enough to perform on-line analysis of five HAAs in the tap water of Taipei City. Four HAAs, including trichloroacetic acid, dichloroacetic acid, dibromoacetic acid, and monobromoacetic acid, were detected at concentrations of approximately 1.74, 1.15, 0.16, and 0.15 ppb, respectively. PMID:24019225

Hung, Sih-Hua; Her, Guor-Rong

2013-11-01

79

Sensitive analysis of antibiotics via hyphenation of field-amplified sample stacking with reversed-field stacking in microchip micellar electrokinetic chromatography.  

PubMed

An on-chip multiple-concentration method combining field-amplified sample stacking (FASS) and reversed-field stacking (RFS) in microchip micellar electrokinetic chromatography (MCMEKC) was developed for the simultaneous analysis of three antibiotics (kanamycin, vancomycin, and gentamycin) using poly (styrene sulfonic acid) sodium salt (PSS) as the pseudostationary phase. Results indicated that the polymeric surfactant PSS provided high stability, unique selectivity, and high efficiency for the separation of these antibiotics as compared to SDS micelles, and the multiple-preconcentration strategy could greatly improve the sensitivity enhancement over those classical CE-LIF methods for antibiotics detection. The stacking and separation mechanism as well as important parameters governing preconcentration and separation have been investigated in order to obtain maximum resolution and sensitivity. Under optimal conditions, three antibiotics were successfully focused and completely separated within <3min. The limits of detection for kanamycin, vancomycin, and gentamycin were 0.25, 0.20, and 0.80?g/L (S/N=3), respectively, and the detection sensitivities were improved 259-, 296-, and 308-fold, respectively. The method also gave accurate and reliable results in the analysis of these antibiotics in river water samples. PMID:25462126

Wu, Minglei; Gao, Fan; Zhang, Yi; Wang, Guan; Wang, Qingjiang; Li, Hui

2014-11-11

80

Polyanions decelerate the kinetics of positively charged gramicidin channels as shown by sensitized photoinactivation.  

PubMed Central

The effects of different anionic polymers on the kinetic properties of ionic channels formed by neutral gramicidin A (gA) and its positively charged analogs gramicidin-tris(2-aminoethyl)amine (gram-TAEA) and gramicidin-ethylenediamine (gram-EDA) in a bilayer lipid membrane were studied using a method of sensitized photoinactivation. The addition of Konig's polyanion caused substantial deceleration of the photoinactivation kinetics of gram-TAEA channels, which expose three positive charges to the aqueous phase at both sides of the membrane. In contrast, channels formed of gram-EDA, which exposes one positive charge, and neutral gA channels were insensitive to Konig's polyanion. The effect strongly depended on the nature of the polyanion added, namely: DNA, RNA, polyacrylic acid, and polyglutamic acid were inactive, whereas modified polyacrylic acid induced deceleration of the channel kinetics at high concentrations. In addition, DNA was able to prevent the action of Konig's polyanion. In single-channel experiments, the addition of Konig's polyanion resulted in the appearance of long-lived gram-TAEA channels. The deceleration of the gram-TAEA channel kinetics was ascribed to electrostatic interaction of the polyanion with gram-TAEA that reduces the mobility of gram-TAEA monomers and dimers in the membrane via clustering of channels. PMID:11867447

Antonenko, Yuri N; Borisenko, Vitali; Melik-Nubarov, Nikolay S; Kotova, Elena A; Woolley, G Andrew

2002-01-01

81

Overexpression of the Adiponectin Receptor AdipoR1 in Rat Skeletal Muscle Amplifies Local Insulin Sensitivity  

PubMed Central

Adiponectin is an adipokine whose plasma levels are inversely related to degrees of insulin resistance (IR) or obesity. It enhances glucose disposal and mitochondrial substrate oxidation in skeletal muscle and its actions are mediated through binding to receptors, especially adiponectin receptor 1 (AdipoR1). However, the in vivo significance of adiponectin sensitivity and the molecular mechanisms of muscle insulin sensitization by adiponectin have not been fully established. We used in vivo electrotransfer to overexpress AdipoR1 in single muscles of rats, some of which were fed for 6 wk with chow or high-fat diet (HFD) and then subjected to hyperinsulinemic-euglycemic clamp. After 1 wk, the effects on glucose disposal, signaling, and sphingolipid metabolism were investigated in test vs. contralateral control muscles. AdipoR1 overexpression (OE) increased glucose uptake and glycogen accumulation in the basal and insulin-treated rat muscle and also in the HFD-fed rats, locally ameliorating muscle IR. These effects were associated with increased phosphorylation of insulin receptor substrate-1, Akt, and glycogen synthase kinase-3?. AdipoR1 OE also caused increased phosphorylation of p70S6 kinase, AMP-activated protein kinase, and acetyl-coA carboxylase as well as increased protein levels of adaptor protein containing pleckstrin homology domain, phosphotyrosine binding domain, and leucine zipper motif-1 and adiponectin, peroxisome proliferator activated receptor-? coactivator-1?, and uncoupling protein-3, indicative of increased mitochondrial biogenesis. Although neither HFD feeding nor AdipoR1 OE caused generalized changes in sphingolipids, AdipoR1 OE did reduce levels of sphingosine 1-phosphate, ceramide 18:1, ceramide 20:2, and dihydroceramide 20:0, plus mRNA levels of the ceramide synthetic enzymes serine palmitoyl transferase and sphingolipid ?-4 desaturase, changes that are associated with increased insulin sensitivity. These data demonstrate that enhancement of local adiponectin sensitivity is sufficient to improve skeletal muscle IR. PMID:22989629

Patel, S. A.; Hoehn, K. L.; Lawrence, R. T.; Sawbridge, L.; Talbot, N. A.; Tomsig, J. L.; Turner, N.; Cooney, G. J.; Whitehead, J. P.; Kraegen, E. W.

2012-01-01

82

Nanoparticle technology: amplifying the effective sensitivity of biomarker detection to create a urine test for hGH.  

PubMed

Several clinical-grade immunoassays exist for the specific measurement of hGH or its isoforms in blood but there is an urgent need to apply these same reliable assays to the measurement of hGH in urine as a preferred 'non-invasive' biofluid. Unfortunately, conventional hGH immunoassays cannot attain the sensitivity required to detect the low concentrations of hGH in urine. The lowest limit of sensitivity for existing hGH immunoassays is >50 pg/mL, while the estimated concentration of urinary hGH is about 1 pg/m-50 times lower than the sensitivity threshold. We have created novel N-isopropylacrylamide (NIPAm)-based hydrogel nanoparticles functionalized with an affinity bait. When introduced into an analyte-containing solution, the nanoparticles can perform, in one step, (1) complete harvesting of all solution phase target analytes, (2) full protection of the captured analyte from degradation and (3) sequestration of the analyte, effectively increasing the analyte concentration up to a hundredfold. N-isopropylacrylamide nanoparticles functionalized with Cibacron Blue F3GA bait have been applied to raise the concentration of urinary hGH into the linear range of clinical grade immunoassays. This technology now provides an opportunity to evaluate the concentration of hGH in urine with high precision and accuracy. PMID:20355230

Fredolini, Claudia; Tamburro, Davide; Gambara, Guido; Lepene, Benjamin S; Espina, Virginia; Petricoin, Emanuel F; Liotta, Lance A; Luchini, Alessandra

2009-09-01

83

Method to protect charge recombination in the back-contact dye-sensitized solar cell.  

PubMed

We prepared a back-contact dye-sensitized solar cell and investigated effect of the sputter deposited thin TiO? film on the back-contact ITO electrode on photovoltaic property. The nanocrystalline TiO? layer with thickness of about 11 ?m formed on a plain glass substrate in the back-contact structure showed higher optical transmittance than that formed on an ITO-coated glass substrate, which led to an improved photocurrent density by about 6.3%. However, photovoltage was found to decrease from 817 mV to 773 mV. The photovoltage recovered after deposition of a 35 nm-thick thin TiO? film on the surface of the back-contact ITO electrode. Little difference in time constant for electron transport was found for the back-contact ITO electrodes with and without the sputter deposited thin TiO? film. Whereas, time constant for charge recombination increased after introduction of the thin TiO? film, indicating that such a thin TiO? film protected back electron transfer, associated with the recovery of photovoltage. As the result of the improved photocurrent density without deterioration of photovoltage, the back-contact dye-sensitized solar cell exhibited 13.6% higher efficiency than the ITO-coated glass substrate-based dye-sensitized solar cell. PMID:21165069

Yoo, Beomjin; Kim, Kang-Jin; Lee, Doh-Kwon; Kim, Kyungkon; Ko, Min Jae; Kim, Yong Hyun; Kim, Won Mok; Park, Nam-Gyu

2010-09-13

84

Operational Amplifiers.  

ERIC Educational Resources Information Center

Addresses the introduction of low cost equipment into high school and college physical science classes. Examines the properties of an "ideal" operational amplifier and discusses how it might be used under saturated and non-saturated conditions. Notes the action of a "real" operational amplifier. (TW)

Foxcroft, G. E.

1986-01-01

85

Switching Amplifiers  

NSDL National Science Digital Library

Created by Work-Ready Electronics, a project of the Advanced Technological Education, this module walks visitors through switching amplifiers. The site content is divided up into four sections: Switching Amplifiers Introduction, Class D Switching Amplifiers, Switching RF Power Amplifiers, and Troubleshooting. There is a quiz for each section to test what students learned in the module in the Knowledge Probe section, and the Learning Resources section contains four activities to help cement student understanding. There are also further resources - both print and Web based - for more information and two Questor games, a Flash quiz that reiterates the material covered. The Notebook function allows visitors to take notes and review them at any time. This is an excellent resource students and educators in electronics technician programs to introduce and explore switching amplifiers.

86

Amplifier Distortion  

NASA Astrophysics Data System (ADS)

By definition, a high fidelity amplifier's instantaneous output voltage is directly proportional to its instantaneous input voltage. While high fidelity is generally valued in the amplification of recorded music, nonlinearity, also known as distortion, is desirable in the amplification of some musical instruments. In particular, guitar amplifiers exploit nonlinearity to increase both the harmonic content and sustain of a guitar's sound. I will discuss how both modifications in sound result from saturation of triode tubes and transistors. Additionally, I will describe the difference in the symmetry of saturation curves for transistors and tubes and the reason why tube guitar amplifiers are generally considered to be superior to solid-state amplifiers. Finally, I will discuss attempts to use solid-state electronics to replicate the sound of tube amplifiers.

Keeports, David

2006-12-01

87

Extreme chemical sensitivity of nonlinear conductivity in charge-ordered LuFe2O4  

PubMed Central

Nonlinear transport behaviors are crucial for applications in electronic technology. At the nonlinear critical turning point, the nonequilibrium states cause rich physics responses to environment. The corresponding study in this field is crucial for physics and industry application. Here nonlinear conductivity in charge-ordered (CO) LuFe2O4 has been demonstrated. Remarkable resistivity switching behavior was observed and the gas-sensing property can be reversibly tuned by a small alternation of partial pressure and/or chemical components of the environment. These facts allow us to use LuFe2O4 materials as a sensitive chemical gas sensor in technological applications. Careful analysis of the gas sensing process in LuFe2O4 suggests a novel sensing mechanism in sharp contrast with that discussed for the conventional gas sensors which depend fundamentally on surface chemical reactions. PMID:22448317

Cao, Shi; Li, Jun; Wang, Zhen; Tian, Huanfang; Qin, Yuanbin; Zeng, Lunjie; Ma, Chao; Yang, Huaixin; Li, Jianqi

2012-01-01

88

Carbon nanomaterials as charge collectors in dye sensitized solar cells and tandems  

NASA Astrophysics Data System (ADS)

This research has set out to understand the physical and electrochemical properties of carbon nanomaterials as charge collector, catalyst and energy transfer induced redox couple modifier in dye sensitized solar cells, which may one day be a major source of electric power generation. This research focuses on (1) characterizing the use of carbon nanotubes, both single walled and multi walled, as catalyst and charge carrier collector (2) improving the performance of the carbon nanotubes with modification by graphene, and various doping (3) testing 2-d carbon nanomaterials, such as graphene and few layer graphene nanoribbons, characterizing an interesting new side effect of photobleaching the iodide/triiodide redox couple, and (4) using the flexibility of dry spun carbon nanotubes sheets and carbon nanotubes sheets for tandem structures and novel fiber architecture. A major motivation in using carbon nanostructures in dye sensitized solar cells is that the standard dye solar cell uses platinum coated on a transparent conductive oxide as the counter electrode. Platinum, a rare and costly metal, is subject to scarcity issues. With proper application, the single walled carbon nanotubes mats could be used for as a substitute that would give efficiencies equivalent to the reference dye solar cells with platinum, and the dry spun multi-walled carbon nanotubes were capable of achieving performance equivalent to platinum with mild doping and nanomaterials additives. The novel architectural design work performed here used these multi-walled carbon nanotubes taken in the form of dry spun sheets. The sheet, possessing a structure of its own, obviates the need for solution processing to create films, which allows it to be used for architectures that demand a freestanding sheet of carbon nanotubes or drawn into a fiber of bundled carbon nanotubes. These freestanding carbon nanotubes were used specifically for the tandem devices and the proposed fiber-based dye solar cells.

Velten, Josef Aaron

89

Interpretation of optoelectronic transient and charge extraction measurements in dye-sensitized solar cells.  

PubMed

Tools that assess the limitations of dye sensitized solar cells (DSSCs) made with new materials are critical for progress. Measuring the transient electrical signals (voltage or current) after optically perturbing a DSSC is an approach which can give information about electron concentration, transport and recombination. Here we describe the theory and practice of this class of optoelectronic measurements, illustrated with numerous examples. The measurements are interpreted with the multiple trapping continuum model which describes electrons in a semiconductor with an exponential distribution of trapping states. We review standard small perturbation photocurrent and photovoltage transients, and introduce the photovoltage time of flight measurement which allows the simultaneous derivation of both effective diffusion and recombination coefficients. We then consider the utility of large perturbation measurements such as charge extraction and the current interrupt technique for finding the internal charge and voltage within a device. Combining these measurements allows differences between DSSCs to be understood in terms such as electron collection efficiency, semiconductor conduction band edge shifts and recombination kinetics. PMID:23404656

Barnes, Piers R F; Miettunen, Kati; Li, Xiaoe; Anderson, Assaf Y; Bessho, Takeru; Gratzel, Michael; O'Regan, Brian C

2013-04-01

90

Sensitive detection of acetylcholine based on a novel boronate intramolecular charge transfer fluorescence probe.  

PubMed

A highly sensitive and selective fluorescence method for the detection of acetylcholine (ACh) based on enzyme-generated hydrogen peroxide (H2O2) and a new boronate intramolecular charge transfer (ICT) fluorescence probe, 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-N-butyl-1,8-naphthalimide (BN), was developed. This strategy involves the reaction of ACh with acetylcholinesterase (AChE) to produce choline, which is further oxidized by choline oxidase (ChOx) to obtain betaine and H2O2. The enzyme-generated H2O2 reacts with BN and results in hydrolytic deprotection of BN to generate fluorescent product (4-hydroxyl-N-butyl-1,8-naphthalimide, ON). Two consecutive linear response ranges allow determining ACh in a wide concentration range with a low detection limit of 2.7nM (signal/noise=3). Compared with other fluorescent probes based on the mechanism of nonspecific oxidation, this reported boronate probe has the advantage of no interference from other biologically relevant reactive oxygen species (ROS) on the detection of ACh. This study provides a new method for the detection of ACh with high selectivity and sensitivity. PMID:25132563

Liu, Chang; Shen, Youming; Yin, Peng; Li, Lidong; Liu, Meiling; Zhang, Youyu; Li, Haitao; Yao, Shouzhuo

2014-08-14

91

Enhanced charge collection in dye-sensitized solar cells utilizing collector-shell electrodes  

NASA Astrophysics Data System (ADS)

Nanostructured porous tin-doped indium oxide (ITO) films were prepared by screen printing of an ITO nanoparticle paste onto conducting fluorine-doped tin oxide (FTO) substrates. The ITO films were subsequently coated with thin layers of TiO2 by the hydrolysis of TiCl4 to form the collector-shell photoelectrodes. The morphology of films was analysed by scanning electron microscope (SEM). It was found that a uniform coating of TiO2 was achieved when three or more deposition cycles were applied. Dye-sensitized solar cells were constructed with the collector-shell photoelectrodes using an electrolyte containing the [Co(bpy)3]2+/3+ (bpy = 2,2?-bipyridine) redox couple and MK-2, an organic sensitizer and efficiencies of 3.3% achieved. Charge transport in cells utilizing the collector-shell electrodes was found to be 2-6 times faster than those utilizing P25-based TiO2 electrodes.

Xiao, Manda; Huang, Fuzhi; Xiang, Wanchun; Cheng, Yi-Bing; Spiccia, Leone

2015-03-01

92

Enhanced performance CCD output amplifier  

DOEpatents

A low-noise FET amplifier is connected to amplify output charge from a che coupled device (CCD). The FET has its gate connected to the CCD in common source configuration for receiving the output charge signal from the CCD and output an intermediate signal at a drain of the FET. An intermediate amplifier is connected to the drain of the FET for receiving the intermediate signal and outputting a low-noise signal functionally related to the output charge signal from the CCD. The amplifier is preferably connected as a virtual ground to the FET drain. The inherent shunt capacitance of the FET is selected to be at least equal to the sum of the remaining capacitances.

Dunham, Mark E. (Los Alamos, NM); Morley, David W. (Santa Fe, NM)

1996-01-01

93

Optical transitions in highly charged californium ions with high sensitivity to variation of the fine-structure constant.  

PubMed

We study electronic transitions in highly charged Cf ions that are within the frequency range of optical lasers and have very high sensitivity to potential variations in the fine-structure constant, ?. The transitions are in the optical range despite the large ionization energies because they lie on the level crossing of the 5f and 6p valence orbitals in the thallium isoelectronic sequence. Cf(16+) is a particularly rich ion, having several narrow lines with properties that minimize certain systematic effects. Cf(16+) has very large nuclear charge and large ionization energy, resulting in the largest ? sensitivity seen in atomic systems. The lines include positive and negative shifters. PMID:23006353

Berengut, J C; Dzuba, V A; Flambaum, V V; Ong, A

2012-08-17

94

Optical Transitions in Highly Charged Californium Ions with High Sensitivity to Variation of the Fine-Structure Constant  

NASA Astrophysics Data System (ADS)

We study electronic transitions in highly charged Cf ions that are within the frequency range of optical lasers and have very high sensitivity to potential variations in the fine-structure constant, ?. The transitions are in the optical range despite the large ionization energies because they lie on the level crossing of the 5f and 6p valence orbitals in the thallium isoelectronic sequence. Cf16+ is a particularly rich ion, having several narrow lines with properties that minimize certain systematic effects. Cf16+ has very large nuclear charge and large ionization energy, resulting in the largest ? sensitivity seen in atomic systems. The lines include positive and negative shifters.

Berengut, J. C.; Dzuba, V. A.; Flambaum, V. V.; Ong, A.

2012-08-01

95

Highly selective and sensitive adenosine aptasensor based on platinum nanoparticles as catalytical label for amplified detection of biorecognition events through H2O2 reduction.  

PubMed

Based on a combination of aptamer and platinum nanoparticles a new sensitive and selective adenosine aptasensor was fabricated. Functionalized thiol-terminated adenosine aptamer (5'-AGAGAACCTGGGGGAGTATTGCGGAGGAAGGT-SH-3') with Pt Nanoparticles (Pt-NPs) was employed as highly catalytic label for electrochemical detection of adenosine based on electrocatalytic activity of Pt-NPs toward H2O2 reduction. Multiwalled carbon nanotubes/ionic liquid/chitosan (MWCNTs/IL/CHIT) nanocomposite was applied as the interface for covalent attachment of 3'-amine-terminated capture probe (3'-NH2-(CH2)6-TCTCTTGGACCC-5'). The presence of Pt nanoparticles improvement the conductivity and performance characteristics of the biosensor as well as incensement in the loading amount of the aptamer DNA sequence. The interaction of adenosine with the aptamer causes the releasing of aptamer with PtNPs into solution which resulted in a decreasing of hydrogen peroxide reduction peak current. Sensitive quantitative detection of adenosine was achieved by monitoring the decrease of voltammetric responses of H2O2 peak current. The peak current of H2O2 decreased with increase in the concentration of adenosine over a range of 1-750 nM with detection limit 1 nM. In addition the proposed aptasensor showed excellent selectivity toward adenosine in compared to some other nucleosides such as guanosine, cytidine and uridine. The proposed aptasensor was successfully used to detect adenosine in human serum samples. The elimination of enzymes or antibodies for the amplified detection of adenosine and the use of platinum nanoparticles as inorganic catalytic label, are the advantage of the proposed aptasensor. PMID:24176972

Shahdost-fard, Faezeh; Salimi, Abdollah; Khezrian, Somayeh

2014-03-15

96

Probing the charge-collection sensitivity profile using a picosecond pulsed laser at a range of wavelengths  

Microsoft Academic Search

A new empirical methodology is defined and demonstrated in which the charge collection sensitivity profile of single-event effect (SEE)-susceptible nodes in microcircuits is calculated on the basis of laser pulse measurements of the upset threshold at a range of wavelengths.

A. M. Chugg; R. Jones; A. Moutrie; C. S. Dyer; C. Sanderson; A. Wraight

2002-01-01

97

Complexation of polyaniline and graphene for efficient counter electrodes in dye-sensitized solar cells: Enhanced charge transfer ability  

NASA Astrophysics Data System (ADS)

With an aim of significantly enhancing charge-transfer ability of counter electrodes and therefore photovoltaic performances of dye-sensitized solar cells (DSSCs), here we pioneerly report the complexation of polyaniline (PANi) and graphene as well as their employment as counter electrodes (CEs) in efficient DSSCs. Owing to the covalent bond between PANi (N atoms) and graphene (C atoms), charge transfer kinetics is dramatically elevated, which can be confirmed by the enhancement on electrocatalytic activity toward triiodides and a decrease in charge-transfer resistance. A power conversion efficiency of 7.70% is determined from DSSC using PANi-8 wt‰ graphene complex CE in comparison with 6.40% from pure PANi CE-based DSSC. The high conversion efficiency, facile charge-transfer in combination with simple preparation, relatively low cost, and scalability demonstrates the potential use of PANi-graphene complexes in robust DSSCs.

He, Benlin; Tang, Qunwei; Wang, Min; Ma, Chunqing; Yuan, Shuangshuang

2014-06-01

98

Bidirectional amplifier  

DOEpatents

A bilateral circuit is operable for transmitting signals in two directions without generation of ringing due to feedback caused by the insertion of the circuit. The circuit may include gain for each of the signals to provide a bidirectional amplifier. The signals are passed through two separate paths, with a unidirectional amplifier in each path. A controlled sampling device is provided in each path for sampling the two signals. Any feedback loop between the two signals is disrupted by providing a phase displacement between the control signals for the two sampling devices.

Wright, J.T.

1984-02-02

99

Bidirectional amplifier  

DOEpatents

A bilateral circuit is operable for transmitting signals in two directions without generation of ringing due to feedback caused by the insertion of the circuit. The circuit may include gain for each of the signals to provide a bidirectional amplifier. The signals are passed through two separate paths, with a unidirectional amplifier in each path. A controlled sampling device is provided in each path for sampling the two signals. Any feedback loop between the two signals is disrupted by providing a phase displacement between the control signals for the two sampling devices.

Wright, James T. (Cedarcrest, NM)

1986-01-01

100

A Simple Capacitive Charge-Division Readout for Position-Sensitive Solid-State Photomultiplier Arrays  

PubMed Central

A capacitive charge-division readout method for reading out a 2 × 2 array of 5 mm × 5 mm position-sensitive solid-state photomultipliers (PS-SSPM) was designed and evaluated. Using this analog multiplexing method, the 20 signals (16 position, 4 timing) from the PS-SSPM array are reduced to 5 signals (4 position, 1 timing), allowing the PS-SSPM array to be treated as an individual large-area PS-SSPM module. A global positioning approach can now be used, instead of individual positioning for each PS-SSPM in the array, ensuring that the entire light signal is utilized. The signal-to-noise ratio (SNR) and flood histogram quality at different bias voltages (27.5 V to 32.0 V at 0.5 V intervals) and a fixed temperature of 0 °C were evaluated by coupling a 6 × 6 array of 1.3 mm × 1.3 mm × 20 mm polished LSO crystals to the center of the PS-SSPM array. The timing resolution was measured at a fixed bias voltage of 31.0 V and a fixed temperature of 0 °C. All the measurements were evaluated and compared using capacitors with different values and tolerances. Capacitor values ranged from 0.051 nf to 10 nf, and the capacitance tolerance ranged from 1% to 20%. The results show that better performance was achieved using capacitors with smaller values and better capacitance tolerance. Using 0.2 nf capacitors, the SNR, energy resolution and timing resolution were 24.3, 18.2% and 8.8 ns at a bias voltage 31.0 V, respectively. The flood histogram quality was also evaluated by using a 10 × 10 array of 1 mm × 1 mm × 10 mm polished LSO crystals and a 10 × 10 array of 0.7 mm × 0.7 mm × 20 mm unpolished LSO crystals to determine the smallest crystal size resolvable. These studies showed that the high spatial resolution of the PS-SSPM was preserved allowing for 0.7 mm crystals to be identified. These results show that the capacitive charge-division analog signal processing method can significantly reduce the number of electronic channels, from 20 to 5, while retaining the excellent performance of the detector.

Du, Junwei; Schmall, Jeffrey P.; Yang, Yongfeng; Di, Kun; Dokhale, Purushottam A.; Shah, Kanai S.; Cherry, Simon R.

2014-01-01

101

Why not only electric discharge but even a minimum charge on the surface of highly sensitive explosives can catalyze their gradual exothermic decomposition and how a cloud of unipolar charged explosive particles turns into ball lightning  

E-print Network

Even a single excess electron or ion migrating on the surface of sensitive explosives can catalyze their gradual exothermic decomposition. Mechanisms underlying such a charge-induced gradual thermal decomposition of highly sensitive explosives can be different. If sensitive explosive is a polar liquid, intense charge-dipole attraction between excess surface charges and surrounding explosive molecules can result in repetitive attempts of solvation of these charges by polar explosive molecules. Every attempt of such uncompleted nonequilibrium solvation causes local exothermic decomposition of thermolabile polar molecules accompanied by further thermal jumping unsolvated excess charges to new surface sites. Thus, ionized mobile hot spots emerge on charged explosive surface. Stochastic migration of ionized hot spots on explosive surface causes gradual exothermic decomposition of the whole mass of the polar explosive. The similar gradual charge-catalyzed exothermic decomposition of both polar and nonpolar highly s...

Meshcheryakov, Oleg

2014-01-01

102

Differential transimpedance amplifier circuit for correlated differential amplification  

DOEpatents

A differential transimpedance amplifier circuit for correlated differential amplification. The amplifier circuit increase electronic signal-to-noise ratios in charge detection circuits designed for the detection of very small quantities of electrical charge and/or very weak electromagnetic waves. A differential, integrating capacitive transimpedance amplifier integrated circuit comprising capacitor feedback loops performs time-correlated subtraction of noise.

Gresham, Christopher A. (Albuquerque, NM); Denton, M. Bonner (Tucson, AZ); Sperline, Roger P. (Tucson, AZ)

2008-07-22

103

Trastuzumab increases the sensitivity of HER2-amplified human gastric cancer cells to oxaliplatin and cisplatin by affecting the expression of telomere-associated proteins  

PubMed Central

HER2 amplification occurs in ~20% of gastric cancer (GC) cases; however, in gastric and gastroesophageal junction cancer with HER2 gene amplification, trastuzumab in combination with cisplatin (DDP)-based chemotherapy has been reported to improve the oncological outcome. The aim of the present study was to evaluate the combined antitumor efficacy of trastuzumab and various platinum agents in GC cells and to elucidate mechanisms that may be involved in the interaction between trastuzumab and the platinum agents. The in vitro chemosensitivity of the GC cells to platinum agents was evaluated using the CellTiter 96® AQueous One Solution Cell Proliferation Assay kit. Treatment with 1.0?g/ml trastuzumab for 48 h significantly increased the sensitivity of NCI-N87 cells with HER2 amplification to oxaliplatin (Oxa) and DDP. This chemosensitivity was most prominent in the NCI-N87 cells, in which the half maximal inhibitory concentration of Oxa and DDP was decreased to ~3.29 and 6.91 times, respectively. The apoptotic effect of the platinum agents was evaluated by double-staining the GC cells with Annexin V-fluorescein isothiocyanate and propodium iodide. Consistent with the chemosensitivity analysis, apoptotic analysis indicated that trastuzumab significantly increased Oxa- and DDP-induced apoptosis in the NCI-N87 cells. Furthermore, the mRNA expression levels of various telomere-associated genes was determined by performing quantitative reverse transcription-polymerase chain reactions in a number of GC cell lines, and revealed that trastuzumab (alone and in combination with DDP) may downregulate the mRNA expression levels of the TPP1, TRF1, TRF2, TRF2IP and POT1 genes. However, western blot analysis demonstrated that trastuzumab (alone and in combination with DDP) may significantly downregulate the protein expression levels of telomeric repeat binding factor 2, protection of telomere 1 and TPP1 (formerly known as TINT1, PTOP and PIP). The results of the present study indicate a potential role of low-dose trastuzumab administration for increasing Oxa and DDP sensitivity in HER2-amplified GC cells, possibly via the downregulation of telomere-associated gene expression. PMID:25624920

LIU, YONGPING; LING, YANG; QI, QIUFENG; ZHU, MING; WAN, MEIZHEN; ZHANG, YAPING; ZHANG, CHANGSONG

2015-01-01

104

Codelivery of Antitumor Drug and Gene by a pH-Sensitive Charge-Conversion System.  

PubMed

In the present study, a gene and drug codelivery system was developed by electrostatic binding of polyethylenimine-poly(l-lysine)-poly(l-glutamic acid) (PELG), polyethylenimine (PEI), cis-aconityl-doxorubicin (CAD), and DNA. Zeta potential and drug release analysis confirmed the pH-responsive charge conversion and acid-sensitive drug release functional properties of the PELG/PEI/(DNA+CAD) system. Gel retardation assay and transfection experiment showed the codelivery system had effective DNA binding ability and good transfection efficiency on HepG2 cells. The therapeutic gene p53 was further employed to study its combinational effects with CAD. Cytotoxicity assay showed the half inhibitory concentration (IC50) of the PELG/PEI/(p53+CAD) codelivery system was lower than that of the gene or the drug delivery system. Confocal laser scanning microscopy (CLSM) showed that the drug and gene could be delivered into the cells simultaneously. A significant increase of p53 gene expression was achieved after HepG2 cells treated by PELG/PEI/(p53+CAD) codelivery system. The apoptosis experiment indicated clearly that the codelivery system could lead an effective apoptosis on tumor cells, which was beneficial for the treatment of cancer. The biodistribution and tumor accumulation of the codelivery system was explored via in vivo imaging in subcutaneous xenograft and in situ tumor models. The tumor and some major organs were excised and imaged, and the results showed that the codelivery system can accumulate efficiently in tumor for both tumor models. It can be suggested from the above results that the PELG/PEI/(DNA+CAD) codelivery system will have great potential applications in cancer therapy. PMID:25581567

Guan, Xiuwen; Li, Yanhui; Jiao, Zixue; Lin, Lin; Chen, Jie; Guo, Zhaopei; Tian, Huayu; Chen, Xuesi

2015-02-11

105

Why not only electric discharge but even a minimum charge on the surface of highly sensitive explosives can catalyze their gradual exothermic decomposition and how a cloud of unipolar charged explosive particles turns into ball lightning  

E-print Network

Even a single excess electron or ion migrating on the surface of sensitive explosives can catalyze their gradual exothermic decomposition. Mechanisms underlying such a charge-induced gradual thermal decomposition of highly sensitive explosives can be different. If sensitive explosive is a polar liquid, intense charge-dipole attraction between excess surface charges and surrounding explosive molecules can result in repetitive attempts of solvation of these charges by polar explosive molecules. Every attempt of such uncompleted nonequilibrium solvation causes local exothermic decomposition of thermolabile polar molecules accompanied by further thermal jumping unsolvated excess charges to new surface sites. Thus, ionized mobile hot spots emerge on charged explosive surface. Stochastic migration of ionized hot spots on explosive surface causes gradual exothermic decomposition of the whole mass of the polar explosive. The similar gradual charge-catalyzed exothermic decomposition of both polar and nonpolar highly sensitive explosives can be also caused by intense charge-dipole attacks of surrounding water vapor molecules electrostatically attracted from ambient humid air and strongly accelerated towards charged sites on explosive surfaces. Emission of electrons, photons and heat from ionized hot spots randomly migrating on charged surface of highly sensitive explosive aerosol nanoparticles converts such particles into the form of short-circuited thermionic nanobatteries.

Oleg Meshcheryakov

2013-07-17

106

Gated charged-particle trap  

DOEpatents

The design and operation of a new type of charged-particle trap provides simultaneous measurements of mass, charge, and velocity of large electrospray ions. The trap consists of a detector tube mounted between two sets of center-bored trapping plates. Voltages applied to the trapping plates define symmetrically-opposing potential valleys which guide axially-injected ions to cycle back and forth through the charge-detection tube. A low noise charge-sensitive amplifier, connected to the tube, reproduces the image charge of individual ions as they pass through the detector tube. Ion mass is calculated from measurement of ion charge and velocity following each passage through the detector. 5 figs.

Benner, W.H.

1999-03-09

107

LC/ESI-MS/MS detection of FAs by charge reversal derivatization with more than four orders of magnitude improvement in sensitivity[S  

PubMed Central

Quantitative analysis of fatty acids (FAs) is an important area of analytical biochemistry. Ultra high sensitivity FA analysis usually is done with gas chromatography of pentafluorobenzyl esters coupled to an electron-capture detector. With the popularity of electrospray ionization (ESI) mass spectrometers coupled to liquid chromatography, it would be convenient to develop a method for ultra high sensitivity FA detection using this equipment. Although FAs can be analyzed by ESI in negative ion mode, this method is not very sensitive. In this study, we demonstrate a new method of FA analysis based on conversion of the carboxylic acid to an amide bearing a permanent positive charge, N-(4-aminomethylphenyl)pyridinium (AMPP) combined with analysis on a reverse-phase liquid chromatography column coupled to an ESI mass spectrometer operating in positive ion mode. This leads to an ?60,000-fold increase in sensitivity compared with the same method carried out with underivatized FAs. The new method is about 10-fold more sensitive than the existing method of gas chromatography/electron-capture mass spectrometry of FA pentafluorobenzyl esters. Furthermore, significant fragmentation of the precursor ions in the nontag portion improves analytical specificity. We show that a large number of FA molecular species can be analyzed with this method in complex biological samples such as mouse serum. PMID:23945566

Bollinger, James G.; Rohan, Gajendra; Sadilek, Martin; Gelb, Michael H.

2013-01-01

108

The effect of temperature on the charge transport and transient absorption properties of K27 sensitized DSSC  

Microsoft Academic Search

The charge transport and transient absorption properties of K27 dye-sensitized solar cell have been investigated. The current–voltage (I–V) characteristics of the solar cell were analyzed by the thermionic emission theory. The ideality factor, barrier height and series resistance values of the solar cell were determined. The ideality factor higher than unity indicated the presence of non-ideal behavior in current–voltage characteristics

Kasim Ocakoglu; Fahrettin Yakuphanoglu; James R. Durrant; Siddik Icli

2008-01-01

109

Operational Amplifiers  

NSDL National Science Digital Library

All About Circuits is a website that ā??provides a series of online textbooks covering electricity and electronics.ā? Written by Tony R. Kuphaldt, the textbooks available here are wonderful resources for students, teachers, and anyone who is interested in learning more about electronics. This specific section, Operational Amplifiers, is the eighth chapter in Volume III ā??Semiconductors. A few of the topics covered in this chapter include: The "operational" amplifier; Negative feedback; Voltage-to-current signal conversion; and Differentiator and integrator circuits. Diagrams and detailed descriptions of concepts are included throughout the chapter to provide users with a comprehensive lesson. Visitors to the site are also encouraged to discuss concepts and topics using the All About Circuits discussion forums (registration with the site is required to post materials).

Kuphaldt, Tony R.

110

Chicago Amplified  

NSDL National Science Digital Library

From the Chicago Public Library to the Lyric Opera, the Chicago Amplified program based at Chicago Public Radio brings the best and the brightest from the Chicago region to anyone with an Internet connection. The program was started in 2006, and visitors can browse past programs all the way back to that year. Clicking on each program will allow users to read a description of the show's content and listen to audio online.

111

Determination of 16O and 18O sensitivity factors and charge-exchange processes in low-energy ion scattering  

NASA Astrophysics Data System (ADS)

Quantitative analysis in low-energy ion scattering (LEIS) requires an understanding of the charge-exchange processes to estimate the elemental sensitivity factors. In this work, the neutralization of He+ scattered by 18O-exchanged silica at energies between 0.6 and 7 keV was studied. The process is dominated by Auger neutralization for Ei < 0.8 keV. An additional mechanism starts above the reionization threshold. This collision-induced neutralization becomes the dominant mechanism for Ei > 2 keV. The ion fractions P+ were determined for Si and O using the characteristic velocity method to quantify the surface density. The 18O/16O sensitivity ratio indicates an 18% higher sensitivity for the heavier O isotope.

Téllez, H.; Chater, R. J.; Fearn, S.; Symianakis, E.; Brongersma, H. H.; Kilner, J. A.

2012-10-01

112

WOLTE_8 Abstract -Workshop on Low Temperature Electronics -June 22-25, 2008 CMOS Charge amplifier for liquid argon Time Projection Chamber detectors  

E-print Network

for liquid argon Time Projection Chamber detectors E. Bechetoille 1 , H. Mathez1 1 IPNL, Universite Lyon 1 We developed an integrated circuit (IC) for the readout of LAr (Liquid Argon) TPC (Time Projection Charge) with a detector capacitance of 250pF. The distribution of charges collected by the wires

Boyer, Edmond

113

STABILITY OF PULSES IN NONLINEAR OPTICAL FIBERS USING PHASESENSITIVE AMPLIFIERS  

E-print Network

STABILITY OF PULSES IN NONLINEAR OPTICAL FIBERS USING PHASEĀ­SENSITIVE AMPLIFIERS J. NATHAN KUTZ y in nonlinear optical fibers with periodicallyĀ­spaced phaseĀ­sensitive amplifiers, a situation where the averaged is carried out, and in the limit of small amplifier spacing, a steadyĀ­state pulse solution is shown

114

Integrating a redox-coupled dye-sensitized photoelectrode into a lithium-oxygen battery for photoassisted charging.  

PubMed

With a high theoretical specific energy, the non-aqueous rechargeable lithium-oxygen battery is a promising next-generation energy storage technique. However, the large charging overpotential remains a challenge due to the difficulty in electrochemically oxidizing the insulating lithium peroxide. Recently, a redox shuttle has been introduced into the electrolyte to chemically oxidize lithium peroxide. Here, we report the use of a triiodide/iodide redox shuttle to couple a built-in dye-sensitized titanium dioxide photoelectrode with the oxygen electrode for the photoassisted charging of a lithium-oxygen battery. On charging under illumination, triiodide ions are generated on the photoelectrode, and subsequently oxidize lithium peroxide. Due to the contribution of the photovoltage, the charging overpotential is greatly reduced. The use of a redox shuttle to couple a photoelectrode and an oxygen electrode offers a unique strategy to address the overpotential issue of non-aqueous lithium-oxygen batteries and also a distinct approach for integrating solar cells and batteries. PMID:25277368

Yu, Mingzhe; Ren, Xiaodi; Ma, Lu; Wu, Yiying

2014-01-01

115

Three dimensional indium-tin-oxide nanorod array for charge collection in dye-sensitized solar cells.  

PubMed

In this article, we report the design, fabrication, characterization, and simulation of three-dimensional (3D) dye-sensitized solar cells (DSSCs), using ordered indium-tin-oxide (ITO) nanorod (NR) arrays as the photoanode, and compare them with conventional planar (2D) DSSCs. The ITO NR array used in the 3D cell greatly improves its performance by providing shorter electron pathways and reducing the recombination rate of the photogenerated electrons. We observed a 10-20% enhancement of the energy conversion efficiency, primarily due to an increased short circuit current. This finding supports the concept of using 3D photoanodes with optically transparent and conducting nanorods for the enhancement of the energy-harvesting devices that require short charge collection distance without sacrificing the optical thickness. Thus, unlike the conventional solar cell structure, the functions for photon collection and charge transport are decoupled to allow for improved cell designs. PMID:25147966

Lee, Byunghong; Guo, Peijun; Li, Shi-Qiang; Buchholz, D Bruce; Chang, Robert P H

2014-10-22

116

Sensitive Determination of Saponins in Radix et Rhizoma Notoginseng by Charged Aerosol Detector Coupled with HPLC  

Microsoft Academic Search

With continuous development in analytical instruments over recent years, high performance liquid chromatography (HPLC) with various detectors has become very important tools for routine analysis and quality control of TCMs and botanical medicines. As a new “mass” detector, charged aerosol detector (CAD) provides an alternative detection method, which ultraviolet (UV) is unable to achieve for components owning almost no chromophore

Chang-Cai Bai; Shu-Yan Han; Xing-Yun Chai; Yong Jiang; Ping Li; Peng-Fei Tu

2008-01-01

117

Interfacial Charge Transfer and Colloidal Semiconductor Dye-Sensitization: Mechanism Assessment via Stark Emission Spectroscopy  

E-print Network

element of many photoelectrochemical solar energy conversion (light to electricity) schemes.1,2 Typically) charge-transfer complex. Examples include catechol,3 thiocy- anate,4 and ferrocyanide5-7 on titanium Preparation. Titanium dioxide14 and zirconium dioxide15 colloids (10 nm diameter) were prep

118

Sensitivity analysis of combustion timing and duration of homogeneous charge compression ignition (HCCI) engines  

Microsoft Academic Search

The goal of this paper is to investigate which factors have a more dominant effect and should be included in a control oriented model that predicts the start of combustion and combustion duration of a homogeneous charge compression ignition (HCCI) engine. Qualitative and quantitative information on the individual effects of fuel and exhaust gas recirculation (EGR) on the HCCI combustion

C. J. Chiang; A. G. Stefanopoulou

2006-01-01

119

Sensitivity Analysis of Combustion Timing and Duration of Homogeneous Charge Compression Ignition (HCCI) Engines  

E-print Network

from high compression ratio and rapid heat release and (ii) low NOx and low particulate matter (PMSensitivity Analysis of Combustion Timing and Duration of Homogeneous Charge Compression Ignition of a homogeneous mixture. The main advantages of HCCI engines include [1]: (i) their high fuel efficiency resulting

Stefanopoulou, Anna

120

Quantum limits on probabilistic amplifiers  

E-print Network

An ideal phase-preserving linear amplifier is a deterministic device that adds to an input signal the minimal amount of noise consistent with the constraints imposed by quantum mechanics. A noiseless linear amplifier takes an input coherent state to an amplified coherent state, but only works part of the time. Such a device is actually better than noiseless, since the output has less noise than the amplified noise of the input coherent state; for this reason we refer to such devices as {\\em immaculate}. Here we bound the working probabilities of probabilistic and approximate immaculate amplifiers and construct theoretical models that achieve some of these bounds. Our chief conclusions are the following: (i) the working probability of any phase-insensitive immaculate amplifier is very small in the phase-plane region where the device works with high fidelity; (ii) phase-sensitive immaculate amplifiers that work only on coherent states sparsely distributed on a phase-plane circle centered at the origin can have a reasonably high working probability.

Shashank Pandey; Zhang Jiang; Joshua Combes; Carlton M. Caves

2013-10-02

121

An avenue of expanding triiodide reduction and shortening charge diffusion length in solid-state dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Enhancement in power conversion efficiency is a persistent pursuit for solid-state dye-sensitized solar cells (DSSCs). We report an experimental strategy of synthesizing I-/I3- doped 3-hydroxypropionitrile/polyaniline (HPN/PANi) solid electrolytes, aiming at expanding I3- reduction reaction from electrolyte/counter electrode interface to solid electrolyte system and shortening the charge diffusion path length. The DSSC with HPN/1.0 wt% PANi shows an efficiency of 3.70% in comparison to 1.49% from the cell with pristine HPN.

Li, Pinjiang; Duan, Yanyan; Tang, Qunwei; He, Benlin; Li, Ru

2015-01-01

122

KPiX, An Array of Self Triggered Charge Sensitive Cells Generating Digital Time and Amplitude Information  

SciTech Connect

The Silicon Detector proposed for the International Linear Collider (ILC) requires electronic read-out that can be tightly coupled to the silicon detectors envisioned for the tracker and the electromagnetic calorimeter. The KPiX is a 1024-channel read-out chip that bump-bonds to the detector and communicates through a few digital signals, power, and detector bias. The KPiX front-end is a low-noise dual-range charge-amplifier with a dynamic range of 17 bit, achieved by autonomous switching of the feedback capacitor. The device takes advantage of the ILC duty cycle of 1 ms trains at 5 Hz rate by lowering the supply current after the data acquisition cycle for an average power consumption of <20 {micro}W/channel. During the 1 ms train, up to four events exceeding a programmable threshold can be stored, the amplitude as a voltage on a capacitor for subsequent digitization, the event time in digital format. The chip can be configured for other than ILC applications.

Freytag, D.; Herbst, R.; /SLAC; Brau, J.; /Oregon U.; Breidenbach, M.; /SLAC; Frey, R.; /Oregon U.; Haller, G.; /SLAC; Holbrook, B.; Lander, R.; /UC, Davis; Nelson, T.; /SLAC; Radeka, V.; /Brookhaven; Strom, D.; /Oregon U.; Tripathi, M.; /UC, Davis

2008-12-11

123

High dynamic range charge measurements  

DOEpatents

A charge amplifier for use in radiation sensing includes an amplifier, at least one switch, and at least one capacitor. The switch selectively couples the input of the switch to one of at least two voltages. The capacitor is electrically coupled in series between the input of the amplifier and the input of the switch. The capacitor is electrically coupled to the input of the amplifier without a switch coupled therebetween. A method of measuring charge in radiation sensing includes selectively diverting charge from an input of an amplifier to an input of at least one capacitor by selectively coupling an output of the at least one capacitor to one of at least two voltages. The input of the at least one capacitor is operatively coupled to the input of the amplifier without a switch coupled therebetween. The method also includes calculating a total charge based on a sum of the amplified charge and the diverted charge.

De Geronimo, Gianluigi

2012-09-04

124

Adenylate energy charge in Escherichia coli CR341T28 and properties of heat-sensitive adenylate kinase.  

PubMed

Escherichia coli strain CR341T28 will not grow at temperatures above 34 degrees C in liquid medium, and the adenylate kinase of this strain is heat sensitive. When a culture was shifted from a permissive (30 degrees C) to a nonpermissive (36 degrees C) temperature, the adenylate energy charge fell from 0.9 to 0.2, with a concurrent decrease in the number of viable cells and in the specific activity of adenylate kinase. When cultures of the temperature-sensitive strain were grown at temperatures above 30 degrees C, the adenylate energy charge, the specific activity of adenylate kinase, and the growth rate were lower than the corresponding parameters for the parental strain. By isotopic labeling of the adenine nucleotides in vivo, it was determined that increasing growth temperatures between 30 and 34 degrees C for the heat-sensitive strain resulted in a decrease in the adenosine triphosphate-to-adenosine monophosphate and adenosine triphosphate-to-adenosine diphosphate ratios. Between 26 and 30 degrees C the adenosine triphosphate-to-adenosine diphosphate ratio was essentially normal in the temperature-sensitive strain, but the adenosine triphosphate-to-adenosine diphosphate ratio was decreased. The adenylate ratios in the parental strain did not change between 30 and 34 degrees C. The adenylate kinase mass action ratio for each strain was essentially constant under all growth conditions. When assayed at 30 degrees C, the affinities of the enzyme from the mutant strain were somewhat lower than those of the parent adenylate kinase. The mutant enzyme also did not exhibit the substrate inhibition that was observed at high adenosine monophosphate concentrations with the parental enzyme. An increase in the assay temperature from 30 degrees to 40 degrees C had little or no effect on the Km values determined for the parental adenylate kinase, but caused the Km values determined for the mutant adenylate kinase to increase by a factor of two or more. PMID:6259132

Glembotski, C C; Chapman, A G; Atkinson, D E

1981-03-01

125

The effect of molecular aggregates over the interfacial charge transfer processes on dye sensitized solar cells  

SciTech Connect

The electron transfer reaction between the photoinjected electrons in the nanocrystalline TiO{sub 2} mesoporous sensitized films and the oxidized electrolyte in dye sensitized solar cells (DSSC) plays a major role on the device efficiency. In this communication we show that, although the presence of molecular aggregates on the free base porphyrin DSSC limits the device photocurrent response under illumination, they form an effective hydrophobic barrier against the oxidized electrolyte impeding fast back-electron transfer kinetics. Therefore, their drawback can be overcome by designing dyes with peripheral moieties that prevent the formation of the aggregates and are able to achieve efficiencies as high as 3.2% under full sun.

Planells, Miquel; Forneli, Amparo; Martinez-Ferrero, Eugenia; Sanchez-Diaz, Antonio; Sarmentero, Maria Angeles [Institute of Chemical Research of Catalonia (ICIQ). Avda. Paiesos Catalans, 16 Tarragona 43007 (Spain); Ballester, Pablo; Palomares, Emilio [Institute of Chemical Research of Catalonia (ICIQ). Avda. Paiesos Catalans, 16 Tarragona 43007 (Spain); Institucio Catalana de Recerca i Estudis Avancats (ICREA), Passeig Lluis Companys, 23 08010 Barcelona (Spain); O'Regan, Brian C. [Centre for Electronic Materials and Devices, Imperial College of London, Exhibition Road, SW7 2AZ London (United Kingdom)

2008-04-14

126

Theoretical studies on effective metal-to-ligand charge transfer characteristics of novel ruthenium dyes for dye sensitized solar cells.  

PubMed

The development of ruthenium dye-sensitizers with highly effective metal-to-ligand charge transfer (MLCT) characteristics and narrowed transition energy gaps are essential for the new generation of dye-sensitized solar cells. Here, we designed a novel anchoring ligand by inserting the cyanovinyl-branches inside the anchoring ligands of selected highly efficient dye-sensitizers and studied their intrinsic optical properties using theoretical methods. Our calculated results show that the designed ruthenium dyes provide good performances as sensitizers compared to the selected efficient dyes, because of their red-shift in the UV-visible absorption spectra with an increase in the absorption intensity, smaller energy gaps and thereby enhancing MLCT transitions. We found that, the designed anchoring ligand acts as an efficient "electron-acceptor" which boosts electron-transfer from a -NCS ligand to this ligand via a Ru-bridge, thus providing a way to lower the transition energy gap and enhance the MLCT transitions. PMID:24743972

Wang, Huei-Tang; Taufany, Fadlilatul; Nachimuthu, Santhanamoorthi; Jiang, Jyh-Chiang

2014-05-01

127

Prognosticating the humic complexation for redox sensitive actinides through analogy, using the charge neutralisation model.  

E-print Network

) that are not retained on a hydrophobic resin and insoluble at acidic pH; fulvic acids (FA) that are retained-sur-Yvette CEDEX, France Abstract The complexation of redox sensitive elements by humic acid (HA), described are still needed to ascertain the plutonium and uranium comportment in the presence of humic acid. * E

Boyer, Edmond

128

Solvent dipole modulation of conduction band edge shift and charge recombination in robust dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Molecular modification is certified as a powerful strategy to adjust the energy alignment and electron transfer dynamics of dye-sensitized solar cells (DSCs). Herein, devices are assembled with three robust solvent (3-methoxypropionitrile, N,N-dimethylformamide and ?-butyrolactone) based electrolytes to elucidate the solvent dipole effects at the semiconductor-dye-electrolyte interface. Photovoltaic results demonstrate that open-circuit photovoltages of the devices vary linearly with the dipole moment of the solvents, along with an adverse dependence of the short-circuit photocurrent density under simulated irradiation. Impedance analysis reveals an apparent dipole moment-modulated conduction band edge shift of the nanocrystalline TiO2 electrodes with respect to the redox potential of the electrolyte. Furthermore, the adverse shifts of the short-circuit photocurrent are explained by a dipole dependence of the driving force for electron injection and the interfacial charge recombination, together with a notably changed charge collection efficiency. Therefore, this study draws attention to the feasibility of tuning the electron transfer dynamics and energy alignment in photoelectrochemical devices by judiciously selecting the electrolyte solvents for further efficiency improvement, especially for those alternative organic sensitizers or quantum dots with inadequate electron injection driven forces.

Hao, Feng; Jiao, Xingjian; Li, Jianbao; Lin, Hong

2012-12-01

129

Fluctuation dynamo amplified  

E-print Network

Fluctuation dynamo amplified by intermittent shear bursts J. Pratt The Fluctuation Dynamo Boussinesq MHD Convection Simulations Shear Bursts: Amplified Energy Production Magnetic Helicity Fluctuation dynamo amplified by intermittent shear bursts J. Pratt Thanks to my collaborators: A. Busse (U. Glasgow

130

Low cost instrumentation amplifier  

NASA Technical Reports Server (NTRS)

Amplifier can be used for many applications requiring high input impedance and common mode rejection, low drift, and gain accuracy on order of one percent. Performance of inexpensive amplifier approaches that of some commercial instrumentation amplifiers in many specifications.

Sturman, J. C.

1974-01-01

131

Instantaneous generation of charge-separated state on TiO? surface sensitized with plasmonic nanoparticles.  

PubMed

Photoexcitation of the plasmon band in metallic nanoparticles adsorbed on a TiO2 surface initiates many important photovoltaic and photocatalytic processes. The traditional view on the photoinduced charge separation involves excitation of a surface plasmon, its subsequent dephasing into electron-hole pairs, followed by electron transfer (ET) from the metal nanoparticle into TiO2. We use nonadiabatic molecular dynamics combined with time-domain density functional theory to demonstrate that an electron appears inside TiO2 immediately upon photoexcitation with a high probability (~50%), bypassing the intermediate step of electron-hole thermalization inside the nanoparticle. By providing a detailed, atomistic description of the charge separation, energy relaxation, and electron-hole recombination processes, the simulation rationalizes why the experimentally observed ultrafast photoinduced ET in an Au-TiO2 system is possible in spite of the fast energy relaxation. The simulation shows that the photogenerated plasmon is highly delocalized onto TiO2, and thus, it is shared by the electron donor and acceptor materials. In the 50% of the cases remaining after the instantaneous photogeneration of the charge-separated state, the electron injects into TiO2 on a sub-100 fs time scale by the nonadiabatic mechanism due to high density of acceptor states. The electron-phonon relaxation parallels the injection and is slower, resulting in a transient heating of the TiO2 surface by 40 K. Driven by entropy, the electron moves further into TiO2 bulk. If the electron remains trapped at the TiO2 surface, it recombines with the hole on a picosecond time scale. The obtained ET and recombination times are in excellent agreement with the experiment. The delocalized plasmon state observed in our study establishes a novel concept for plasmonic photosensitization of wide band gap semiconductors, leading to efficient conversion of photons to charge carriers and to hybrid materials with a wide variety of applications in photocatalysis and photovoltaics. PMID:24568726

Long, Run; Prezhdo, Oleg V

2014-03-19

132

Semiconductor optical amplifiers for future optical networks  

Microsoft Academic Search

This work describes the principal applications of SOAs in optical communication systems. They can be classified into three areas: (a) postamplifier or booster amplifier to increase transmitter laser power, (b) in-line amplifier to compensate for fiber and other transmission losses in medium and long-haul links and (c) preamplifier to improve receiver sensitivity. SOAs are used in both linear and nonlinear

A. Sharaiha

2004-01-01

133

Improvement in light harvesting in a dye sensitized solar cell based on cascade charge transfer.  

PubMed

Dye sensitized solar cells (DSSCs) offer the potential of being low-cost, high-efficiency photovoltaic devices. However, the power conversion efficiency is limited as they cannot utilize all photons of the visible solar spectrum. A novel design of a core-shell photoanode is presented herein where a thin shell of infrared dye is deposited over the core of a sensitized TiO2 nanofiber. Specifically, a ruthenium based dye (N719) sensitized TiO2 nanofiber is wrapped by a thin shell of copper phthalocyanine (CuPc). In addition to broadening the absorption spectrum, this core-shell configuration further suppresses the electron-hole recombination process. Instead of adopting the typical Förster resonance energy transfer, upon photons being absorbed by the infrared dye, electrons are transferred efficiently through a cascade process from the CuPc to the N719 dye, the conduction band of TiO2, the FTO electrode and finally the external circuit. Concurrently, photons are also absorbed by the N719 dye with electrons being transferred in the cell. These additive effects result in a high power conversion efficiency of 9.48% for the device. The proposed strategy provides an alternative method for enhancing the performance of DSSCs for low-cost renewable energy in the future. PMID:23831867

Yang, Lijun; Leung, Wallace Woon-Fong; Wang, Jingchuan

2013-08-21

134

Understanding sensitization behavior of lead selenide photoconductive detectors by charge separation model  

NASA Astrophysics Data System (ADS)

We introduce a charge separation model in this work to explain the mechanism of enhanced photoconductivity of polycrystalline lead salt photoconductors. Our results show that this model could clarify the heuristic fabrication processes of such lead salt detectors that were not well understood and often considered mysterious for nearly a century. The improved lifetime and performance of the device, e.g., responsivity, are attributed to the spatial separation of holes and electrons, hence less possibility of carrier recombination. This model shows that in addition to crystal quality the size of crystallites, the depth of outer conversion layer, and doping concentration could all affect detector performance. The simulation results agree well with experimental results and thus offer a very useful tool for further improvement of lead salt detectors. The model was developed with lead salt family of photoconductors in mind, but may well be applicable to a wider class of semiconducting films.

Zhao, Lihua; Qiu, Jijun; Weng, Binbin; Chang, Caleb; Yuan, Zijian; Shi, Zhisheng

2014-02-01

135

Understanding sensitization behavior of lead selenide photoconductive detectors by charge separation model  

SciTech Connect

We introduce a charge separation model in this work to explain the mechanism of enhanced photoconductivity of polycrystalline lead salt photoconductors. Our results show that this model could clarify the heuristic fabrication processes of such lead salt detectors that were not well understood and often considered mysterious for nearly a century. The improved lifetime and performance of the device, e.g., responsivity, are attributed to the spatial separation of holes and electrons, hence less possibility of carrier recombination. This model shows that in addition to crystal quality the size of crystallites, the depth of outer conversion layer, and doping concentration could all affect detector performance. The simulation results agree well with experimental results and thus offer a very useful tool for further improvement of lead salt detectors. The model was developed with lead salt family of photoconductors in mind, but may well be applicable to a wider class of semiconducting films.

Zhao, Lihua, E-mail: lihua.zhao@ou.edu, E-mail: shi@ou.edu; Qiu, Jijun; Weng, Binbin; Chang, Caleb; Yuan, Zijian; Shi, Zhisheng, E-mail: lihua.zhao@ou.edu, E-mail: shi@ou.edu [School of Electrical and Computer Engineering, University of Oklahoma, Norman, Oklahoma 73019 (United States)

2014-02-28

136

Position and time sensitive photon counting detector with image charge delay-line readout  

NASA Astrophysics Data System (ADS)

We have developed single photon counting image intensifier tubes combining position and time information read-out with at least 500x500 pixels and sub-nanosecond time resolution. This image intensifier type uses a resistive screen instead of a phosphor screen and the image charge pickup anode is placed outside the sealed tube. We present a novel delay-line anode design which allows for instance detecting simultaneously arriving pairs of photons. Due to the very low background this technique is suited for applications with very low light intensity and especially if a precise time tagging for each photon is required. We show results obtained with several anode types on a 25 mm image intensifier tube and a 40 mm open-face MCP detector and discuss the performance in neutron radiography, e.g. for homeland security, and the prospects for applications like Fluorescence Life-time Imaging Microscopy (FLIM), astronomy and X-ray polarimetry.

Czasch, Achim; Dangendorf, Volker; Milnes, James; Schössler, Sven; Lauck, Ronald; Spillmann, Uwe; Howorth, Jon; Jagutzki, Ottmar

2007-09-01

137

Signal and noise analysis of a-Si:H radiation detector-amplifier system  

SciTech Connect

Hydrogenated amorphous silicon (a-Si:H) has potential advantages in making radiation detectors for many applications because of its deposition capability on a large-area substrate and its high radiation resistance. Position-sensitive radiation detectors can be made out of a 1d strip or a 2-d pixel array of a Si:H pin diodes. In addition, signal processing electronics can be made by thin-film transistors on the same substrate. The calculated radiation signal, based on a simple charge collection model agreed well with results from various wave length light sources and 1 MeV beta particles on sample diodes. The total noise of the detection system was analyzed into (a) shot noise and (b) 1/f noise from a detector diode, and (c) thermal noise and (d) 1/f noise from the frontend TFT of a charge-sensitive preamplifier. the effective noise charge calculated by convoluting these noise power spectra with the transfer function of a CR-RC shaping amplifier showed a good agreement with the direct measurements of noise charge. The derived equations of signal and noise charge can be used to design an a-Si:H pixel detector amplifier system optimally. Signals from a pixel can be readout using switching TFTs, or diodes. Prototype tests of a double-diode readout scheme showed that the storage time and the readout time are limited by the resistances of the reverse-biased pixel diode and the forward biased switching diodes respectively. A prototype charge-sensitive amplifier was made using poly-Si TFTs to test the feasibility of making pixel-level amplifiers which would be required in small-signal detection. The measured overall gain-bandwidth product was {approximately}400 MHz and the noise charge {approximately}1000 electrons at a 1 {mu}sec shaping time. When the amplifier is connected to a pixel detector of capacitance 0.2 pF, it would give a charge-to-voltage gain of {approximately}0.02 mV/electron with a pulse rise time less than 100 nsec and a dynamic range of 48 dB.

Cho, Gyuseong

1992-03-01

138

EHF Solid State Amplifier  

Microsoft Academic Search

Two 5 watts Q-band solid state amplifiers have been developed. These amplifiers have a minimum of 24 dB gain over a 2 GHz bandwidth. The amplifier can operate from -20°C to +65°C utilizing an electronic temperature stabilization circuit. The experimental test results and the integration of the amplifiers will be presented in this paper.

G. H. Nesbit; W. H. Leighton

1985-01-01

139

Fluorescent probing of protein bovine serum albumin stability and denaturation using polarity sensitive spectral response of a charge transfer probe.  

PubMed

The polarity sensitive photo-induced intra-molecular charge transfer (ICT) fluorescence probe (E)-3-(4-methylamino-phenyl)-acrylic acid ethyl ester (MAPAEE) has been used to study the model protein Bovine Serum Albumin (BSA) in its native and thermal and urea induced denatured states. The interaction between BSA and the regular surfactant Sodium Dodecyl Sulphate (SDS) as well as the biologically relevant steroid-based amphiphile Sodium Deoxycholate (NaDC) has also been very keenly followed using this ICT probe. The variation of micellar properties of both SDS and NaDC with increasing ionic strengths and in presence of the chaotrope urea has also been well documemted by the same probe. Steady-state spectroscopy, FRET, and fluorescence anisotropy measurements have been used to gain better insight into these processes and the molecule MAPAEE to be a full-bodied fluorescent probe for studying such intricate biological systems, their properties and interactions. PMID:20922468

Ghosh, Shalini; Jana, Sankar; Nath, Debnarayan; Guchhait, Nikhil

2011-01-01

140

Holographic modification of TiO{sub 2} nanostructure for enhanced charge transport in dye-sensitized solar cell  

SciTech Connect

We show that the photocurrent and energy conversion efficiency of dye-sensitized solar cells can be greatly enhanced with holographic modification to the morphology of TiO{sub 2} electrode. The nanoporous electrode coated onto conducting glass was irradiated by three interfering laser beams at 1064 nm incident from the backside of the substrate. This generated two-dimensional periodic pillars of higher density in the electrode, through which the photoexcited electrons could be extracted more effectively. The cells fabricated with modified electrodes exhibited average photocurrent and efficiency of 17.14 mA/cm{sup 2} and 9.03%, while 14.91 mA/cm{sup 2} and 7.83% were obtained from the reference cells. It was attributed to the enhanced charge transport accompanied by the reduction of internal resistance of the electrode.

Lee, Jinsoo; Yoon, Junghwan; Jin, Minhea; Lee, Myeongkyu [Department of Materials Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of)

2012-08-15

141

Holographic modification of TiO2 nanostructure for enhanced charge transport in dye-sensitized solar cell  

NASA Astrophysics Data System (ADS)

We show that the photocurrent and energy conversion efficiency of dye-sensitized solar cells can be greatly enhanced with holographic modification to the morphology of TiO2 electrode. The nanoporous electrode coated onto conducting glass was irradiated by three interfering laser beams at 1064 nm incident from the backside of the substrate. This generated two-dimensional periodic pillars of higher density in the electrode, through which the photoexcited electrons could be extracted more effectively. The cells fabricated with modified electrodes exhibited average photocurrent and efficiency of 17.14 mA/cm2 and 9.03%, while 14.91 mA/cm2 and 7.83% were obtained from the reference cells. It was attributed to the enhanced charge transport accompanied by the reduction of internal resistance of the electrode.

Lee, Jinsoo; Yoon, Junghwan; Jin, Minhea; Lee, Myeongkyu

2012-08-01

142

Amplified OTDR systems for multipoint corrosion monitoring.  

PubMed

We present two configurations of an amplified fiber-optic-based corrosion sensor using the optical time domain reflectometry (OTDR) technique as the interrogation method. The sensor system is multipoint, self-referenced, has no moving parts and can measure the corrosion rate several kilometers away from the OTDR equipment. The first OTDR monitoring system employs a remotely pumped in-line EDFA and it is used to evaluate the increase in system reach compared to a non-amplified configuration. The other amplified monitoring system uses an EDFA in booster configuration and we perform corrosion measurements and evaluations of system sensitivity to amplifier gain variations. Our experimental results obtained under controlled laboratory conditions show the advantages of the amplified system in terms of longer system reach with better spatial resolution, and also that the corrosion measurements obtained from our system are not sensitive to 3 dB gain variations. PMID:22737017

Nascimento, Jehan F; Silva, Marcionilo J; Coźlho, Isnaldo J S; Cipriano, Eliel; Martins-Filho, Joaquim F

2012-01-01

143

Amplified OTDR Systems for Multipoint Corrosion Monitoring  

PubMed Central

We present two configurations of an amplified fiber-optic-based corrosion sensor using the optical time domain reflectometry (OTDR) technique as the interrogation method. The sensor system is multipoint, self-referenced, has no moving parts and can measure the corrosion rate several kilometers away from the OTDR equipment. The first OTDR monitoring system employs a remotely pumped in-line EDFA and it is used to evaluate the increase in system reach compared to a non-amplified configuration. The other amplified monitoring system uses an EDFA in booster configuration and we perform corrosion measurements and evaluations of system sensitivity to amplifier gain variations. Our experimental results obtained under controlled laboratory conditions show the advantages of the amplified system in terms of longer system reach with better spatial resolution, and also that the corrosion measurements obtained from our system are not sensitive to 3 dB gain variations. PMID:22737017

Nascimento, Jehan F.; Silva, Marcionilo J.; Coźlho, Isnaldo J. S.; Cipriano, Eliel; Martins-Filho, Joaquim F.

2012-01-01

144

Amplified quantum transforms  

NASA Astrophysics Data System (ADS)

In this thesis we investigate two new Amplified Quantum Transforms. In particular we create and analyze the Amplified Quantum Fourier Transform (Amplified-QFT) and the Amplified-Haar Wavelet Transform. The Amplified-QFT algorithm is used to solve the Local Period Problem. We calculate the probabilities of success and compare this algorithm with the QFT and QHS algorithms. We also examine the Amplified-QFT algorithm for solving the Local Period Problem with Error Stream. We use the Amplified-Haar Wavelet Transform for solving the Local Constant or Balanced Signal Decision Problem which is a generalization of the Deutsch-Jozsa problem.

Cornwell, David J.

145

Understanding interfacial charge transfer between metallic PEDOT counter electrodes and a cobalt redox shuttle in dye-sensitized solar cells.  

PubMed

Conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) doped with iron(III) tris-p-toluenesulfonate (PEDOT:Tos) having metallic conductivity was coated onto fluorine-doped tin oxide (FTO) glass and plain glass substrates and used as a counter electrode (CE) in a dye-sensitized solar cell (DSC) with a [Co(bpy)3](3+/2+) complex redox shuttle. DSCs with PEDOT:Tos/glass CE yielded power conversion efficiencies (PCE) of 6.3%, similar to that of DSCs with platinized FTO glass CE (6.1%). The PEDOT:Tos-based counter electrodes had 5 to 10 times lower charge-transfer resistance than the Pt/FTO CE in DSCs, as analyzed by impedance spectroscopy. More detailed studies in symmetrical CE-CE cells showed that the PEDOT:Tos layers are nanoporous. Not all internal area can be used catalytically under solar cell conditions and effective charge-transfer resistance was similar to that of Pt/FTO. PMID:24410094

Park, Byung-wook; Pazoki, Meysam; Aitola, Kerttu; Jeong, Seunghee; Johansson, Erik M J; Hagfeldt, Anders; Boschloo, Gerrit

2014-02-12

146

An Acoustic Charge Transport Imager for High Definition Television Applications: Low-Voltage SAW Amplifiers on Multilayer GaAs/ZnO Substrates  

NASA Technical Reports Server (NTRS)

This thesis addresses the acoustoelectric issues concerning the amplification of surface acoustic waves (SAWs) and the reflection of SAWs from slanted reflector gratings on GaAs, with application to a novel acoustic charge transport (ACT) device architecture. First a simple model of the SAWAMP was developed, which was subsequently used to define the epitaxially grown material structure necessary to provide simultaneously high resistance and high electron mobility. In addition, a segmented SAWAMP structure was explored with line widths on the order of an acoustic wavelength. This resulted in the demonstration of SAWAMPS with an order of magnitude less voltage and power requirements than previously reported devices. A two-dimensional model was developed to explain the performance of devices with charge confinement layers less then 0.5 mm, which was experimentally verified. This model was extended to predict a greatly increased gain from the addition of a ZnO overlay. These overlays were experimentally attempted, but no working devices were reported due to process incompatibilities. In addition to the SAWAMP research, the reflection of SAWs from slanted gratings on GaAs was also studied and experimentally determined reflection coefficients for both 45 deg grooves and Al stripes on GaAs have been reported for the first time. The SAWAMp and reflector gratings were combined to investigate the integrated ring oscillator for application to the proposed ACT device and design parameters for this device have been provided.

Hunt, W. D.; Brennan, K. F.; Summers, C. J.; Cameron, Thomas P.

1996-01-01

147

Holevo capacity of attenuation channels assisted by linear amplifiers  

SciTech Connect

We derive a capacity formula for attenuation channels assisted by quantum linear amplifiers when the input signal states are restricted to Gaussian states with the same correlation matrix. A phase insensitive linear amplifier and a phase sensitive linear amplifier are compared by using this formula.

Sohma, Masaki; Hirota, Osamu [Quantum Information Science Research Center, Tamagawa University Research Institute, Machida 194-8610 (Japan)

2007-08-15

148

Sensitivity of HCN channel deactivation to cAMP is amplified by an S4 mutation combined with activation mode shift  

Microsoft Academic Search

Hyperpolarisation–activation of HCN ion channels relies on the movement of a charged S4 transmembrane helix, preferentially\\u000a stabilising the open conformation of the ion pore gate. The open state is additionally stabilised, (a) when cyclic AMP (cAMP)\\u000a is bound to a cytoplasmic C-terminal domain or (b) when the “mode I” open state formed initially by gate opening undergoes\\u000a a “mode shift”

Nadine L. Wicks; Kerry S. C. Chan; Zarina Madden; Bina Santoro; Edgar C. Young

2009-01-01

149

Design and synthesis of a highly sensitive off-on fluorescent chemosensor for zinc ions utilizing internal charge transfer.  

PubMed

Fluorescence imaging is a powerful tool for the visualization of biological molecules in living cells, tissue slices, and whole bodies, and is important for elucidating biological phenomena. Furthermore, zinc (Zn(2+)) is the second most abundant heavy metal ion in the human body after iron, and detection of chelatable Zn(2+) in biological studies has attracted much attention. Herein, we present a novel, highly sensitive off-on fluorescent chemosensor for Zn(2+) by using the internal charge transfer (ICT) mechanism. The rationale of our approach to highly sensitive sensor molecules is as follows. If fluorescence can be completely quenched in the absence of Zn(2+), chemosensors would offer a better signal-to-noise ratio. However, it is difficult to quench the fluorescence completely before Zn(2+) binding, and most sensor molecules still show very weak fluorescence in the absence of Zn(2+). But even though the sensor shows a weak fluorescence in the absence of Zn(2+), this fluorescence can be further suppressed by selecting an excitation wavelength that is barely absorbed by the Zn(2+)-free sensor molecule. Focusing on careful control of ICT within the 4-amino-1,8-naphthalimide dye platform, we designed and synthesized a new chemosensor (1) that shows a pronounced fluorescence enhancement with a blueshift in the absorption spectrum upon addition of Zn(2+). The usefulness of 1 for monitoring Zn(2+) changes was confirmed in living HeLa cells. There have been several reports on 4-amino-1,8-naphthalimide-based fluorescent sensor molecules. However, 1 is the first Zn(2+)-sensitive off-on fluorescent sensor molecule that employs the ICT mechanism; most off-on sensor molecules for Zn(2+) employ the photoinduced electron transfer (PeT) mechanism. PMID:19918808

Hanaoka, Kenjiro; Muramatsu, Yasuaki; Urano, Yasuteru; Terai, Takuya; Nagano, Tetsuo

2010-01-11

150

Simple, sensitive and selective spectrophotometric methods for the determination of atenolol in pharmaceuticals through charge transfer complex formation reaction.  

PubMed

Three rapid, selective and sensitive spectrophotometric methods have been proposed for the quantitative determination of atenolol (ATN) in pure form as well as in its pharmaceutical formulation. The methods are based on charge transfer complexation reaction of ATN as n-electron donor with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), 2,4-dinitrophenol (DNP) and 2,4,6-trinitrophenol (picric acid; PA) as pi-acceptors to give highly colored radical anion species. The colored products were quantified spectrophotometrically at 590 nm with DDQ (method A) and at 420 nm with both DNP (method B) and PA (method C). Under the optimized experimental conditions, Beer's law is obeyed over the concentration ranges of 3-48, 2-24 and 1.5-18 ?g/mL ATN for method A, method B and method C, respectively. The molar absorptivity, Sandell sensitivity, limits of detection and quantification are also reported. The effects of reaction medium, reaction time and reagent concentration on the sensitivity and stability of the complexes formed have been examined. The proposed methods were successfully applied to the determination of ATN in pure form and commercial tablets with good accuracy and precision. Statistical comparison of the results was performed using Student's t-test and F-ratio at 95% confidence level and the results showed no significant difference between the reference and proposed methods with regard to accuracy and precision. Further, the accuracy and reliability of the methods were confirmed by recovery studies via standard addition technique. PMID:22568035

Prashanth, Kudige Nagaraju; Basavaiah, Kanakapura

2012-01-01

151

Terahertz wave parametric amplifier.  

PubMed

The importance of terahertz (THz) wave techniques has been demonstrated in various fields, and the range of applications is now expanding rapidly. However, the practical implementation of THz science to solve the real-world problems is restricted due to the lack not only of convenient high power THz wave emitters and sensitive detectors but also of efficient quasi-optical active devices such as amplifiers. In this work, we demonstrate the direct amplification of THz waves in room temperature using magnesium oxide-doped lithium niobate (MgO:LiNbO3) crystals as the nonlinear gain medium. The input THz wave is injected as a seed beam along with the pump beam into the nonlinear crystal and it is amplified by the optical parametric process. We report gain in excess of 30 dB with an input THz pulse energy of less than 1 pJ. We believe that this demonstration will contribute to the convenience and further applicability of THz frequency techniques. PMID:24690860

Tripathi, Saroj R; Taira, Yuusuke; Hayashi, Shin'ichiro; Nawata, Kouji; Murate, Kousuke; Minamide, Hiroaki; Kawase, Kodo

2014-03-15

152

Amplified Quantum Transforms  

E-print Network

In this thesis we investigate two new Amplified Quantum Transforms. In particular we create and analyze the Amplified Quantum Fourier Transform (Amplified-QFT) and the Amplified-Haar Wavelet Transform. First, we provide a brief history of quantum mechanics and quantum computing. Second, we examine the Amplified-QFT in detail and compare it against the Quantum Fourier Transform (QFT) and Quantum Hidden Subgroup (QHS) algorithms for solving the Local Period Problem. We calculate the probabilities of success of each algorithm and show the Amplified-QFT is quadratically faster than the QFT and QHS algorithms. Third, we examine the Amplified-QFT algorithm for solving The Local Period Problem with an Error Stream. Fourth, we produce an uncertainty relation for the Amplified-QFT algorithm. Fifth, we show how the Amplified-Haar Wavelet Transform can solve the Local Constant or Balanced Signal Decision Problem which is a generalization of the Deutsch-Jozsa algorithm.

David Cornwell

2014-06-01

153

Cross-differential amplifier  

NASA Technical Reports Server (NTRS)

A cross-differential amplifier is provided. The cross-differential amplifier includes an inductor connected to a direct current power source at a first terminal. A first and second switch, such as transistors, are connected to the inductor at a second terminal. A first and second amplifier are connected at their supply terminals to the first and second switch. The first and second switches are operated to commutate the inductor between the amplifiers so as to provide an amplified signal while limiting the ripple voltage on the inductor and thus limiting the maximum voltage imposed across the amplifiers and switches.

Hajimiri, Seyed-Ali (Inventor); Kee, Scott D. (Inventor); Aoki, Ichiro (Inventor)

2011-01-01

154

Cross-differential amplifier  

NASA Technical Reports Server (NTRS)

A cross-differential amplifier is provided. The cross-differential amplifier includes an inductor connected to a direct current power source at a first terminal. A first and second switch, such as transistors, are connected to the inductor at a second terminal. A first and second amplifier are connected at their supply terminals to the first and second switch. The first and second switches are operated to commutate the inductor between the amplifiers so as to provide an amplified signal while limiting the ripple voltage on the inductor and thus limiting the maximum voltage imposed across the amplifiers and switches.

Hajimiri, Seyed-Ali (Inventor); Kee, Scott D. (Inventor); Aoki, Ichiro (Inventor)

2008-01-01

155

Hybrid matrix amplifier  

DOEpatents

The present invention comprises a novel matrix amplifier. The matrix amplifier includes an active superconducting power divider (ASPD) having N output ports; N distributed amplifiers each operatively connected to one of the N output ports of the ASPD; and a power combiner having N input ports each operatively connected to one of the N distributed amplifiers. The distributed amplifier can included M stages of amplification by cascading superconducting active devices. The power combiner can include N active elements. The resulting (N.times.M) matrix amplifier can produce signals of high output power, large bandwidth, and low noise.

Martens, Jon S. (Sunnyvale, CA); Hietala, Vincent M. (Placitas, NM); Plut, Thomas A. (Albuquerque, NM)

1995-01-01

156

Cross-differential amplifier  

NASA Technical Reports Server (NTRS)

A cross-differential amplifier is provided. The cross-differential amplifier includes an inductor connected to a direct current power source at a first terminal. A first and second switch, such as transistors, are connected to the inductor at a second terminal. A first and second amplifier are connected at their supply terminals to the first and second switch. The first and second switches are operated to commutate the inductor between the amplifiers so as to provide an amplified signal while limiting the ripple voltage on the inductor and thus limiting the maximum voltage imposed across the amplifiers and switches.

Hajimiri, Seyed-Ali (Inventor); Kee, Scott D. (Inventor); Aoki, Ichiro (Inventor)

2010-01-01

157

Cross-differential amplifier  

NASA Technical Reports Server (NTRS)

A cross-differential amplifier is provided. The cross-differential amplifier includes an inductor connected to a direct current power source at a first terminal. A first and second switch, such as transistors, are connected to the inductor at a second terminal. A first and second amplifier are connected at their supply terminals to the first and second switch. The first and second switches are operated to commutate the inductor between the amplifiers so as to provide an amplified signal while limiting the ripple voltage on the inductor and thus limiting the maximum voltage imposed across the amplifiers and switches.

Hajimiri, Seyed-Ali (Inventor); Kee, Scott D. (Inventor); Aoki, Ichiro (Inventor)

2013-01-01

158

Progress on diamond amplified photo-cathode  

SciTech Connect

Two years ago, we obtained an emission gain of 40 from the Diamond Amplifier Cathode (DAC) in our test system. In our current systematic study of hydrogenation, the highest gain we registered in emission scanning was 178. We proved that our treatments for improving the diamond amplifiers are reproducible. Upcoming tests planned include testing DAC in a RF cavity. Already, we have designed a system for these tests using our 112 MHz superconducting cavity, wherein we will measure DAC parameters, such as the limit, if any, on emission current density, the bunch charge, and the bunch length. The diamond-amplified photocathode, that promises to support a high average current, low emittance, and a highly stable electron beam with a long lifetime, is under development for an electron source. The diamond, functioning as a secondary emitter amplifies the primary current, with a few KeV energy, that comes from the traditional cathode. Earlier, our group recorded a maximum gain of 40 in the secondary electron emission from a diamond amplifier. In this article, we detail our optimization of the hydrogenation process for a diamond amplifier that resulted in a stable emission gain of 140. We proved that these characteristics are reproducible. We now are designing a system to test the diamond amplifier cathode using an 112MHz SRF gun to measure the limits of the emission current's density, and on the bunch charge and bunch length.

Wang, E.; Ben-Zvi, I.; Burrill, A.; Kewisch, J.; Chang, X.; Rao, T.; Smedley, J.; Wu, Q.; Muller, E.; Xin, T.

2011-03-28

159

Modulated charge injection in p-type dye-sensitized solar cells using fluorene-based light absorbers.  

PubMed

In this study, new pull-push arylamine-fluorene based organic dyes zzx-op1, zzx-op2, and zzx-op3 have been designed and synthesized for p-type dye-sensitized solar cells (p-DSCs). In zzx-op1, a di(p-carboxyphenyl)amine (DCPA) was used as an electron donor, a perylenemonoimide (PMID) as an electron acceptor, and a fluorene (FLU) unit with two aliphatic hexyl chains as a ?-conjugated linker. In zzx-op2 and zzx-op3, a 3,4-ethylenedioxythiophene (EDOT) and a thiophene were inserted consecutively between PMID and FLU to tune the energy levels of the frontier molecular orbitals of the dyes. The structural modification broadened the spectral coverage from an onset of 700 nm for zzx-op1 to 750 nm for zzx-op3. The electron-rich EDOT and thiophene lifted up the HOMO (highest occupied molecular orbital) levels of zzx-op2 and zzx-op3, making their potential more negative than zzx-op1. When three dyes were employed in p-type DSCs with I(-)/I3(-) as a redox couple and NiO nanoparticles as hole materials, zzx-op1 exhibited impressive energy conversion efficiency of 0.184% with the open-circuit voltage (VOC) of 112 mV and the short-circuit current density (JSC) of 4.36 mA cm(-2) under AM 1.5G condition. Density functional theory calculations, transient photovoltage decay measurements, and electrochemical impedance spectroscopic studies revealed that zzx-op1 sensitized solar cell exhibited much higher charge injection efficiency (90.3%) than zzx-op2 (53.9%) and zzx-op3 (39.0%), indicating a trade-off between spectral broadening and electron injection driving force in p-type DSCs. PMID:24521135

Liu, Zonghao; Xiong, Dehua; Xu, Xiaobao; Arooj, Qudsia; Wang, Huan; Yin, Liyuan; Li, Wenhui; Wu, Huaizhi; Zhao, Zhixin; Chen, Wei; Wang, Mingkui; Wang, Feng; Cheng, Yi-Bing; He, Hongshan

2014-03-12

160

Stable photosensor amplifiers  

NASA Technical Reports Server (NTRS)

Minimization of common mode effects in differential amplifier arrangement which processes signals from two high impedance photosensors is achieved by connecting one photosensor in feedback loop of amplifier and using field effect transistors in the input circuit.

Fujimoto, H.

1972-01-01

161

Portable musical instrument amplifier  

DOEpatents

The present invention relates to a musical instrument amplifier which is particularly useful for electric guitars. The amplifier has a rigid body for housing both the electronic system for amplifying and processing signals from the guitar and the system's power supply. An input plug connected to and projecting from the body is electrically coupled to the signal amplifying and processing system. When the plug is inserted into an output jack for an electric guitar, the body is rigidly carried by the guitar, and the guitar is operatively connected to the electrical amplifying and signal processing system without use of a loose interconnection cable. The amplifier is provided with an output jack, into which headphones are plugged to receive amplified signals from the guitar. By eliminating the conventional interconnection cable, the amplifier of the present invention can be used by musicians with increased flexibility and greater freedom of movement.

Christian, David E. (Danbury, CT)

1990-07-24

162

Highly sensitive protein detection by combination of atomic force microscopy fishing with charge generation and mass spectrometry analysis.  

PubMed

An approach combining atomic force microscopy (AFM) fishing and mass spectrometry (MS) analysis to detect proteins at ultra-low concentrations is proposed. Fishing out protein molecules onto a highly oriented pyrolytic graphite surface coated with polytetrafluoroethylene film was carried out with and without application of an external electric field. After that they were visualized by AFM and identified by MS. It was found that injection of solution leads to charge generation in the solution, and an electric potential within the measuring cell is induced. It was demonstrated that without an external electric field in the rapid injection input of diluted protein solution the fishing is efficient, as opposed to slow fluid input. The high sensitivity of this method was demonstrated by detection of human serum albumin and human cytochrome b5 in 10(-17) -10(-18) m water solutions. It was shown that an external negative voltage applied to highly oriented pyrolytic graphite hinders the protein fishing. The efficiency of fishing with an external positive voltage was similar to that obtained without applying any voltage. PMID:25145394

Ivanov, Yuri D; Pleshakova, Tatyana; Malsagova, Krystina; Kozlov, Andrey; Kaysheva, Anna; Kopylov, Arthur; Izotov, Alexander; Andreeva, Elena; Kanashenko, Sergey; Usanov, Sergey; Archakov, Alexander

2014-10-01

163

Efficient triarylamine-perylene dye-sensitized solar cells: influence of triple-bond insertion on charge recombination.  

PubMed

We synthesize two new metal-free donor-acceptor organic dyes (C266 and C267) featuring a N-annulated perylene block. Owing to the improved coplanarity of conjugated units as well as the prolonged conjugation upon inserting a triple bond between the triarylamine and perylene segments, the C267 dye exhibits a slightly red-shifted absorption peak and an enhanced maximum molar absorption coefficient with respect to its reference dye C266, leading to an improved photocurrent output in dye-sensitized solar cells. However, the triple-bond introduction also brings forth an over 100 mV reduced open-circuit photovoltage owing to faster interfacial charge recombination, which presents a clear correlation with a reduced mean thickness of self-assembled dye layer on titania as revealed by X-ray reflectivity measurements. The C266 dye, albeit with a relatively weaker light-harvesting capacity, displays a higher power conversion efficiency of 9.0% under the 100 mW cm(-2), simulated AM1.5G sunlight. PMID:25493711

Yan, Cancan; Ma, Wentao; Ren, Yameng; Zhang, Min; Wang, Peng

2015-01-14

164

Structure and charging of hydrophobic material/water interfaces studied by phase-sensitive sum-frequency vibrational spectroscopy  

PubMed Central

We have studied the hydrophobic water/octadecyltrichlorosilane (OTS) interface by using the phase-sensitive sum-frequency vibrational spectroscopy (PS-SFVS), and we obtained detailed structural information of the interface at the molecular level. Excess ions emerging at the interface were detected by changes of the surface vibrational spectrum induced by the surface field created by the excess ions. Both hydronium (H3O+) and hydroxide (OH?) ions were found to adsorb at the interface, and so did other negative ions such as Cl?. By varying the ion concentrations in the bulk water, their adsorption isotherms were measured. It was seen that among the three, OH? has the highest adsorption energy, and H3O+ has the lowest; OH? also has the highest saturation coverage, and Cl? has the lowest. The result shows that even the neat water/OTS interface is not neutral, but charged with OH? ions. The result also explains the surprising observation that the isoelectric point appeared at ?3.0 when HCl was used to decrease the pH starting from neat water. PMID:19706483

Tian, C. S.; Shen, Y. R.

2009-01-01

165

Electronics Operational Amplifiers  

E-print Network

ECEN 325 Electronics Operational Amplifiers Dr. Aydin Ilker KarĀøsilayan Texas A&M University Electronics - Aydin I. KarĀøsilayan - Operational Amplifiers 1 #12;Equivalent CircuitEquivalent Circuit i=0 i=0 Electronics - Aydin I. KarĀøsilayan - Operational Amplifiers 2 #12;vo vs. vdvo vs. vd Slope = A SAT vd vp vn

Palermo, Sam

166

Highly selective and sensitive electrochemical biosensor for ATP based on the dual strategy integrating the cofactor-dependent enzymatic ligation reaction with self-cleaving DNAzyme-amplified electrochemical detection.  

PubMed

A dual strategy that combines the adenosine triphosphate (ATP)-dependent enzymatic ligation reaction with self-cleaving DNAzyme-amplified electrochemical detection is employed to construct the biosensor. In this design, the methylene blue-labeled hairpin-structured DNA was self-assembled onto a gold electrode surface to prepare the modified electrode through the interaction of Au-S bond. In the procedure of ATP-dependent ligation reaction, when the specific cofactor ATP was added, the two split oligonucleotide fragments of 8-17 DNAzyme were linked by T4 DNA ligase and then released to hybridize with the labeled hairpin-structured DNA substrate. The linked 8-17 DNAzyme catalyzes the cleavage of the hairpin-structured substrate by the addition of Zn(2+), causing the methylene blue which contains high electrochemical activity to leave the surface of the gold electrode, therefore generating a dramatic decrease of electrochemical signal. The decrease of peak current was readily measured by square wave voltammetry and a relatively low detection limit (0.05 nM) was obtained with a linear response range from 0.1 to 1000 nM. By taking advantage of the highly specific cofactor dependence of the DNA ligation reaction, the proposed ligation-induced DNAzyme cascades demonstrate ultrahigh selectivity toward the target cofactor ATP. A catalytic and molecular beacons strategy is further adopted to amplify the electrochemical signal detection achieved by cycling and regenerating the 8-17 DNAzyme to realize enzymatic multiple turnover, thus one DNAzyme can catalyze the cleavage of several hairpin-structured substrates, which improves the sensitivity of the newly designed electrochemical sensing system. PMID:25048448

Lu, Lu; Si, Jing Cao; Gao, Zhong Feng; Zhang, Yu; Lei, Jing Lei; Luo, Hong Qun; Li, Nian Bing

2015-01-15

167

Photo-induced charge transfer at heterogeneous interfaces: Dye-sensitized tin disulfide, the theory and the experiment  

Microsoft Academic Search

The study of photo-induced charge transfer is an endeavor that spans the entire industrial period of man`s history. Its great importance demands an ever greater understanding of its underlying principles. The work discussed here attempts to probe elementary aspects of the charge transfer process. Investigations into the theory of charge transfer reactions are made in an attempt to isolate the

Lanzafame

1993-01-01

168

A sensitive and selective mercury(II) sensor based on amplified fluorescence quenching in a conjugated polyelectrolyte/spiro-cyclic rhodamine system.  

PubMed

A novel fluorescence-based sensor for mercury(II) ion is described consisting of a water-soluble, anionic-conjugated polyelectrolyte (CPE) and spiro-cyclic rhodamine derivative (1). A solution containing the CPE (0.1 × 10(-6) M repeat unit concentration) and 1 (1 × 10(-6) M concentration) in aqueous solution exhibits a sensitive and selective turn-off fluorescence response to Hg(II). The Stern-Volmer quenching constant for quenching of the fluorescence of the system by Hg(II) is ?1.5 × 10(7) M(-1) , and Hg(II) can be sensed with a detection limit <10 × 10(-9) M. A mechanism for the sensor response is proposed and it consists of efficient and selective complex formation between 1 and Hg(II), along with a very high association between the 1-Hg(II) complex and the anionic CPE. PMID:23529859

Lee, Seoung Ho; Parthasarathy, Anand; Schanze, Kirk S

2013-05-14

169

pH-, sugar-, and temperature-sensitive electrochemical switch amplified by enzymatic reaction and controlled by logic gates based on semi-interpenetrating polymer networks.  

PubMed

Phenylboronic acid (PBA) moieties are grafted onto the backbone of poly(acrylic acid) (PAA), forming the PAA-PBA polyelectrolyte. The semi-interpenetrating polymer network (semi-IPN) films composed of PAA-PBA and poly(N,N-diethylacrylamide) (PDEA) were then synthesized on electrode surface with entrapped horseradish peroxidase (HRP), designated as PDEA-(PAA-PBA)-HRP. The films demonstrated reversible pH-, fructose-, and thermo-responsive on-off behavior toward electroactive probe K(3)Fe(CN)(6) in its cyclic voltammetric (CV) response. This multiswitchable CV behavior of the system could be further employed to control and modulate the electrochemical reduction of H(2)O(2) catalyzed by HRP immobilized in the films with K(3)Fe(CN)(6) as the mediator in solution. The responsive mechanism of the system was also explored and discussed. The pH-sensitive property was attributed to the electrostatic interaction between the PAA component of the films and the probe at different pH; the thermo-responsive behavior originated from the structure change of PDEA hydrogel component of the films with temperature; the fructose-sensitive property was ascribed to the structure change of the films induced by the complexation between the PBA constituent and the sugar. This smart system could be used as a 3-input logic network composed of enabled OR (EnOR) gates in chemical or biomolecular computing by combining the multiresponsive property of the films and the amplification effect of bioelectrocatalysis and demonstrated the potential perspective for fabricating novel multiswitchable electrochemical biosensors and bioelectronic devices. PMID:22239642

Liu, Dan; Liu, Hongyun; Hu, Naifei

2012-02-01

170

Laser amplifier chain  

DOEpatents

A laser amplifier chain has a plurality of laser amplifiers arranged in a chain to sequentially amplify a low-power signal beam to produce a significantly higher-power output beam. Overall efficiency of such a chain is improved if high-gain, low efficiency amplifiers are placed on the upstream side of the chain where only a very small fraction of the total pumped power is received by the chain and low-gain, high-efficiency amplifiers are placed on the downstream side where a majority of pumping energy is received by the chain.

Hackel, Richard P. (Livermore, CA)

1992-01-01

171

Laser amplifier chain  

DOEpatents

A laser amplifier chain has a plurality of laser amplifiers arranged in a chain to sequentially amplify a low-power signal beam to produce a significantly higher-power output beam. Overall efficiency of such a chain is improved if high-gain, low efficiency amplifiers are placed on the upstream side of the chain where only a very small fraction of the total pumped power is received by the chain and low-gain, high-efficiency amplifiers are placed on the downstream side where a majority of pumping energy is received by the chain. 6 figs.

Hackel, R.P.

1992-10-20

172

Diode amplifier of modulated optical beam power  

NASA Astrophysics Data System (ADS)

Analytical relations are obtained between characteristics of modulated light at the output and input of an optical diode power amplifier operating in the highly saturated gain regime. It is shown that a diode amplifier may act as an amplitude-to-phase modulation converter with a rather large bandwidth (~10 GHz). The low sensitivity of the output power of the amplifier to the input beam power and its high energy efficiency allow it to be used as a building block of a high-power multielement laser system with coherent summation of a large number of optical beams.

D'yachkov, N. V.; Bogatov, A. P.; Gushchik, T. I.; Drakin, A. E.

2014-11-01

173

Primer on the Lock-in Amplifier  

NSDL National Science Digital Library

This is an experiment designed to measure the resistance of copper and gold nanowires using a lock-in amplifier. Students learn: 1. about different types of noise, 2. the principles of phase-sensitive techniques, 3. to extract signals buried in noise using a lock-in amplifier, 4. to operate optical chopper to measure weak optical signals modulated at a certain frequency. 4. to measure the minute resistance of a conducting nanowires.

Farooq, Sidra; Salman, Rabiya; Zia, Wasif; Hassan, Umer; Anwar, Muhammad S.

2012-02-10

174

Thermal recovery of NIF amplifiers  

SciTech Connect

The issue of thermal recovery of the NIF amplifiers has taken on increased emphasis as program goals move toward increasing the shot rate to once every four hours. This paper addresses the technical issues associated with achieving thermal recovery in the NIF amplifiers. We identify two temperature related thermal recovery quantities: (1) the difference between the average slab temperature and the temperature of other surfaces in the amplifier cavity, and (2) the temperature difference in the slab over the aperture. The first quantity relates to optical disturbances in the gas column in the system, while the second quantity is associated with optical aberrations in the laser media itself. Calculations and experiments are used to quantify recovery criteria, and develop cooling approaches. The cooling approaches discussed are (1) active cooling of the flashlamps with ambient gas and chilled gas, and (2) active cooling of the slab edge cladding. Calculations indicate that the NIF baseline cooling approach of 20 cfm per lamp ambient temperature gas flow in both the central and side flashlamp cassettes is capable of meeting thermal recovery requirements for an 8 hour shot period, while to achieve a 4 hour shot period requires use of chilled gas and edge cladding cooling. In addition, the effect of changing the amplifier cavity and beamtube fill gas from nitrogen to helium is addressed, showing that a factor of 8 reduction in the sensitivity to thermal disturbances is possible. 6 refs., 9 figs., 1 tab.

Sutton, S.; Marshall, C.; Petty, C.; Smith, L.; van Wonterghem, B.; Mills, S.

1997-02-01

175

Charge-conversional and reduction-sensitive poly(vinyl alcohol) nanogels for enhanced cell uptake and efficient intracellular doxorubicin release.  

PubMed

Charge-conversional and reduction-sensitive polyvinyl alcohol (PVA) nanogels were developed for efficient cancer treatment by enhanced cell uptake and intracellular triggered doxorubicin (DOX) release. These PVA nanogels were prepared in a straightforward manner by inverse nanoprecipitation via "click" reaction with an average diameter of 118nm. The introduction of COOH into the PVA nanogels efficiently improved the DOX encapsulation due to the electrostatic interaction. The in vitro release result showed that the decrease of electrostatic interaction between COOH and DOX under a mimicking endosomal pH, in combination with the cleavage of the intervening disulfide bonds in response to a high glutathione (GSH) concentration led to a fast and complete release of DOX. Furthermore, confocal laser scanning microscopy (CLSM) revealed that the ultra pH-sensitive terminal groups allowed nanogels to reverse their surface charge from negative to positive under a tumor extracellular pH (6.5-6.8) which facilitated cell internalization. MTT assays and real time cell analysis (RTCA) showed that these DOX-loaded charge-conversional and reducible PVA nanogels had much better cell toxicity than DOX-loaded non-charge-conversional or reduction-insensitive PVA nanogels following 48h of incubation. These novel charge-conversional and stimuli-responsive PVA nanogels are highly promising for targeted intracellular anticancer drug release. PMID:25445693

Chen, Wei; Achazi, Katharina; Schade, Boris; Haag, Rainer

2014-11-20

176

Wireless Josephson amplifier  

SciTech Connect

Josephson junction parametric amplifiers are playing a crucial role in the readout chain in superconducting quantum information experiments. However, their integration with current 3D cavity implementations poses the problem of transitioning between waveguide, coax cables, and planar circuits. Moreover, Josephson amplifiers require auxiliary microwave components, like directional couplers and/or hybrids, that are sources of spurious losses and impedance mismatches that limit measurement efficiency and amplifier tunability. We have developed a wireless architecture for these parametric amplifiers that eliminates superfluous microwave components and interconnects. This greatly simplifies their assembly and integration into experiments. We present an experimental realization of such a device operating in the 9–11?GHz band with about 100?MHz of amplitude gain-bandwidth product, on par with devices mounted in conventional sample holders. The simpler impedance environment presented to the amplifier also results in increased amplifier tunability.

Narla, A.; Sliwa, K. M.; Hatridge, M.; Shankar, S.; Frunzio, L.; Schoelkopf, R. J.; Devoret, M. H. [Department of Applied Physics, Yale University, New Haven, Connecticut 06511 (United States)

2014-06-09

177

Wireless Josephson Amplifier  

E-print Network

Josephson junction parametric amplifiers are playing a crucial role in the readout chain in superconducting quantum information experiments. However, their integration with current 3D cavity implementations poses the problem of transitioning between waveguide, coax cables and planar circuits. Moreover, Josephson amplifiers require auxiliary microwave components, like directional couplers and/or hybrids, that are sources of spurious losses and impedance mismatches that limit measurement efficiency and amplifier tunability. We have developed a new wireless architecture for these parametric amplifiers that eliminates superfluous microwave components and interconnects. This greatly simplifies their assembly and integration into experiments. We present an experimental realization of such a device operating in the $9-11$ GHz band with about $100$ MHz of amplitude gain-bandwidth product, on par with devices mounted in conventional sample holders. The simpler impedance environment presented to the amplifier also results in increased amplifier tunability.

A. Narla; K. M. Sliwa; M. Hatridge; S. Shankar; L. Frunzio; R. J. Schoelkopf; M. H. Devoret

2014-04-19

178

Wireless Josephson amplifier  

NASA Astrophysics Data System (ADS)

Josephson junction parametric amplifiers are playing a crucial role in the readout chain in superconducting quantum information experiments. However, their integration with current 3D cavity implementations poses the problem of transitioning between waveguide, coax cables, and planar circuits. Moreover, Josephson amplifiers require auxiliary microwave components, like directional couplers and/or hybrids, that are sources of spurious losses and impedance mismatches that limit measurement efficiency and amplifier tunability. We have developed a wireless architecture for these parametric amplifiers that eliminates superfluous microwave components and interconnects. This greatly simplifies their assembly and integration into experiments. We present an experimental realization of such a device operating in the 9-11 GHz band with about 100 MHz of amplitude gain-bandwidth product, on par with devices mounted in conventional sample holders. The simpler impedance environment presented to the amplifier also results in increased amplifier tunability.

Narla, A.; Sliwa, K. M.; Hatridge, M.; Shankar, S.; Frunzio, L.; Schoelkopf, R. J.; Devoret, M. H.

2014-06-01

179

Sensitivity of combustion and ignition characteristics of the solid-fuel charge of the microelectromechanical system of a microthruster to macrokinetic and design parameters  

NASA Astrophysics Data System (ADS)

We have developed a sensitivity analysis permitting effective estimation of the change in the impulse responses of a microthrusters and in the ignition characteristics of the solid-fuel charge caused by the variation of the basic macrokinetic parameters of the mixed fuel and the design parameters of the microthruster's combustion chamber. On the basis of the proposed sensitivity analysis, we have estimated the spread of both the propulsive force and impulse and the induction period and self-ignition temperature depending on the macrokinetic parameters of combustion (pre-exponential factor, activation energy, density, and heat content) of the solid-fuel charge of the microthruster. The obtained results can be used for rapid and effective estimation of the spread of goal functions to provide stable physicochemical characteristics and impulse responses of solid-fuel mixtures in making and using microthrusters.

Futko, S. I.; Ermolaeva, E. M.; Dobrego, K. V.; Bondarenko, V. P.; Dolgii, L. N.

2012-07-01

180

A simple and sensitive method for visual detection of heparin using positively-charged gold nanoparticles as colorimetric probes.  

PubMed

The electrostatic interaction between the negatively-charged heparin and the positively-charged gold nanoparticles leads to aggregation of gold nanoparticles and a color change from red to blue in solution, thus providing a simple and visual approach to colorimetric detection of heparin. PMID:21246153

Cao, Rui; Li, Baoxin

2011-03-14

181

Amplifiers and Active Systems  

NSDL National Science Digital Library

Created by Tony R. Kuphaldt, this chapter of All About Circuit's third volume on Semiconductors describes amplifiers and active devices. The chapter is divided into seven sections: From electric to electronic, Active versus passive devices, Amplifiers, Amplifier gain, Decibels, Absolute dB scales, and Attenuators. Each section has clear illustrations and a concise, bulleted review of what was covered at the end. There is also a link to the All About Circuits forums, where contributors and other visitors discuss the material presented. This is an excellent resource for educators in physics and electronic engineering classrooms to introduce lessons or units on amplifiers.

Kuphaldt, Tony R.

182

Altering the self-organization of dyes on titania with dyeing solvents to tune the charge-transfer dynamics of sensitized solar cells.  

PubMed

Herein we selected the model organic donor-acceptor dye C218 and modulated the self-organization of dye molecules on the surface of titania by changing the dyeing solvent from chlorobenzene to a mixture of acetonitrile and tert-butanol. We further unveiled the relationship between the microstructure of a dye layer and the multichannel charge-transfer dynamics that underlie the photovoltaic performance of dye-sensitized solar cells. PMID:24375950

Wang, Yinglin; Yang, Lin; Zhang, Jing; Li, Renzhi; Zhang, Min; Wang, Peng

2014-04-14

183

Ultrafast polarisation spectroscopy of photoinduced charges in a conjugated polymer  

SciTech Connect

Tunable optical parametric generators and amplifiers (OPA), proposed and developed by Akhmanov and his colleagues, have become the working horses in exploration of dynamical processes in physics, chemistry, and biology. In this paper, we demonstrate the possibility of using ultrafast polarisation-sensitive two-colour spectroscopy, performed with a set of two OPAs, to study charge photogeneration and transport in conjugated polymers and their donor-acceptor blends. (special issue devoted to the 80th birthday of S.A. Akhmanov)

Bakulin, A A; Loosdrecht, P van; Pshenichnikov, M S [Zernike Institute for Advanced Materials, University of Groningen, Groningen (Netherlands); Parashchuk, D Yu [M. V. Lomonosov Moscow State University, Faculty of Physics, Moscow (Russian Federation)

2009-07-31

184

LABORATORY 4 Amplifier Design Using Operational Amplifiers (OP-AMPs)  

E-print Network

ELEC 225 LABORATORY 4 Amplifier Design Using Operational Amplifiers (OP-AMPs) In ELEC 120, you designed circuits using the LM35 temperature sensor, DC fan, 741 operational amplifier, OPA 551 operational amplifier, and Light Emitting Diodes (LEDs). In this lab, we will focus on the design of an amplifier

Kozick, Richard J.

185

Tanh cascode cell amplifier an arbitrary transfer characteristics amplifier  

E-print Network

Tanh cascode cell amplifier Ā­ an arbitrary transfer characteristics amplifier M. Ding and K.G. Gard An arbitrary transfer characteristic (TC) amplifier, called the tanh cascode cell (TCC) amplifier, is reported. This novel amplifier is capable of synthesising an arbitrary TC including the ideal rectifier transfer

186

10.0 Operational Amplifiers 1 of 25 Differential Amplifiers  

E-print Network

10.0 Operational Amplifiers 1 of 25 Differential Amplifiers #12;10.0 Operational Amplifiers 2 of 25 #12;10.0 Operational Amplifiers 3 of 25 Single Input Ā­ Single Output Gain Single Input Ā­ Differential Output Gain Difference Input Ā­ Dual Output Gain Common Mode Gain #12;10.0 Operational Amplifiers 4 of 25

Allen, Gale

187

Improved Microwave Amplifiers Based on the dc SQUID  

NASA Astrophysics Data System (ADS)

The dc SQUID can be used as a sensitive microwave amplifier if the signal to be amplified is suitably coupled to the SQUID. We have designed and fabricated microwave amplifiers in which a coil integrated on top of the SQUID is operated as a half-wavelength-microstrip resonator. Such amplifiers have a power gain of up to 100 at 1 GHz, and 4 at 8 GHz. When cooled to millikelvin temperatures, sensitivities close to the quantum limited could be obtained at 500 MHz. By applying negative feedback and adding a few passive components, the input and output impedances of the amplifiers can be brought close to 50 ohms, with only a modest reduction in gain. The robust match to 50 ohms makes it possible to cascade multiple SQUID gain stages, and thereby enhance device performance. We describe novel configurations of the input resonator that allow operation at higher frequencies, and discuss application of these amplifiers to the readout of superconducting quantum circuits.

Chen, Yung-Fu; Hover, David; Maurer, Leon; Sendelbach, Steve; McDermott, Robert; Mueck, Michael

2010-03-01

188

Dye laser amplifier  

DOEpatents

An improved dye laser amplifier is disclosed. The efficiency of the dye laser amplifier is increased significantly by increasing the power of a dye beam as it passes from an input window to an output window within the dye chamber, while maintaining the intensity of the dye beam constant. 3 figs.

Moses, E.I.

1992-12-01

189

Determination of {sup 16}O and {sup 18}O sensitivity factors and charge-exchange processes in low-energy ion scattering  

SciTech Connect

Quantitative analysis in low-energy ion scattering (LEIS) requires an understanding of the charge-exchange processes to estimate the elemental sensitivity factors. In this work, the neutralization of He{sup +} scattered by {sup 18}O-exchanged silica at energies between 0.6 and 7 keV was studied. The process is dominated by Auger neutralization for E{sub i} < 0.8 keV. An additional mechanism starts above the reionization threshold. This collision-induced neutralization becomes the dominant mechanism for E{sub i} > 2 keV. The ion fractions P{sup +} were determined for Si and O using the characteristic velocity method to quantify the surface density. The {sup 18}O/{sup 16}O sensitivity ratio indicates an 18% higher sensitivity for the heavier O isotope.

Tellez, H.; Chater, R. J.; Fearn, S.; Symianakis, E.; Kilner, J. A. [Department of Materials, Imperial College, SW7 2AZ London (United Kingdom); Brongersma, H. H. [Department of Materials, Imperial College, SW7 2AZ London (United Kingdom); Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands)

2012-10-08

190

Universal signal conditioning amplifier  

NASA Technical Reports Server (NTRS)

A state-of-the-art instrumentation amplifier capable of being used with most types of transducers has been developed at the Kennedy Space Center. This Universal Signal Conditioning Amplifier (USCA) can eliminate costly measurement setup item and troubleshooting, improve system reliability and provide more accurate data than conventional amplifiers. The USCA can configure itself for maximum resolution and accuracy based on information read from a RAM chip attached to each transducer. Excitation voltages or current are also automatically configured. The amplifier uses both analog and digital state-of-the-art technology with analog-to-digital conversion performed in the early stages in order to minimize errors introduced by offset and gain drifts in the analog components. A dynamic temperature compensation scheme has been designed to achieve and maintain 12-bit accuracy of the amplifier from 0 to 70 C. The digital signal processing section allows the implementation of digital filters up to 511th order. The amplifier can also perform real-time linearizations up to fourth order while processing data at a rate of 23.438 kS/s. Both digital and analog outputs are available from the amplifier.

Medelius, Pedro J.; Hallberg, Carl; Cecil, Jim

1994-01-01

191

Tuning Broadband Microwave Amplifiers  

SciTech Connect

The PEP-II/DA {Phi} NE/ALS longitudinal feedback systems are complex wide bandwidth systems requiring analog, digital and microwave circuits. The solid-state amplifier is one of the components in the microwave circuit that is required to suppress the coupled bunch instabilities that exist in the PEP-II accelerator. The suppression is achieved by using an antenna as a kicker structure that provides an electric field in order to increase or decrease the energy of particles passing through the structure. The amplifier is made up of sixteen 30 to 35W microstrip GaAs FET modules that are combined to obtain 500W over a bandwidth of 850MHz to 1850MHz. The amplifier malfunctioned causing a reduction in the functionality and power output of the individual GaAs FET modules. The amplifier must be repaired. After repair, the amplifier must be tuned to optimize the gain while maintaining proper power output. The amplifier is tuned using microstrip circuit techniques. A variety of microstrip methods are used to obtain the proper line impedance. The result is a working amplifier that operates efficiently.

Alaniz, Gabriel

2003-09-05

192

Solid state radiographic image amplifiers, part C  

NASA Technical Reports Server (NTRS)

The contrast sensitivity of the radiographic amplifiers, both the storage type and nonstorage type, their absolute sensitivity, and the reproducibility of fabrication were investigated. The required 2-2T quality level was reached with the radiographic storage screen. The sensitivity threshold was 100 to 200 mR with 45 to 100 kV filtered X-rays. The quality level of the radiographic amplifier screen (without storage) was 4-4T; for a 6 mm (0.25 in.) thick aluminum specimen, a 1 mm (0.040 in.) diameter hole in a 0.25 mm (0.010 in.) thick penetrameter was detected. Its sensitivity threshold was 2 to 6 mR/min. The developed radiographic screens are applicable for uses in nondestructive testing.

Szepesi, Z.

1971-01-01

193

Semiconducting polymer optical amplifiers  

NASA Astrophysics Data System (ADS)

In this paper we report studies of gain in organic semiconductors, both in solution and the solid-state. OC1C10-PPV and F8BT solution amplifiers yielded gain of up to 40 dB and on average 30 dB across the spectral range 530-640 nm. We also present a conjugated polymer solid-state amplifier structure, which delivered amplification of 18 dB in a 300 ?m channel length. The material used in the solid state amplifier was Dow RedF which had its high gain and low loss properties optimized by blending with F8BT.

Goosens, M.; Heliotis, G.; Turnbull, G. A.; Ruseckas, A.; Lawrence, J. R.; Xia, R.; Bradley, D. D. C.; Samuel, Ifor D. W.

2005-10-01

194

Visualizing interfacial charge transfer in Ru-dye sensitized TiO{sub 2} nanoparticles using x-ray transient absorption spectroscopy.  

SciTech Connect

A molecular level understanding of the structural reorganization accompanying interfacial electron transfer is important for rational design of solar cells. Here we have applied XTA (X-ray transient absorption) spectroscopy to study transient structures in a heterogeneous interfacial system mimicking the charge separation process in dye-sensitized solar cell (DSSC) with Ru(dcbpy){sub 2}(NCS){sub 2} (RuN3) dye adsorbed to TiO{sub 2} nanoparticle surfaces. The results show that the average Ru-NCS bond length reduces by 0.06 {angstrom}, whereas the average Ru?N(dcbpy) bond length remains nearly unchanged after the electron injection. The differences in bond-order change and steric hindrance between two types of ligands are attributed to their structural response in the charge separation. This study extends the application of XTA into optically opaque hybrid interfacial systems relevant to the solar energy conversion.

Zhang, X.; Smolentsev, G.; Guo, J.; Attenkofer, K.; Kurtz, C.; Jennings, G.; Lockard, J. V.; Stickrath, A. B.; Chen, L. X. (Chemical Sciences and Engineering Division); ( XSD); (Southern Federal Univ.); (Lund Univ.); (Northwestern Univ.)

2011-03-01

195

A guanine-linked end-effect is a sensitive reporter of charge flow through DNA and RNA double helices  

Microsoft Academic Search

The property of charge (electron hole) flow in DNA duplexes has been the subject of intensive study. RNA–DNA heteroduplexes have also been investigated; however, little information exists on the conductive properties of purely RNA duplexes. In investigating the relative conductive properties of a three molecule DNA–DNA duplex design, using piperidine and aniline to break strands at modified bases, we observed

Lucien Junior Bergeron; Kaushiki Sen; Dipankar Sen

2008-01-01

196

EE 321 Amplifiers Fall 2008 Amplifiers, Biasing, and AC Coupling  

E-print Network

EE 321 Amplifiers Fall 2008 EE321 Lab Amplifiers, Biasing, and AC Coupling The purpose of this lab is to measure the characteristics of an amplifier, and to use the characteristics to add a bias circuit at the input. An amplifier can be represented in many different ways. Figure 1 shows a model for a voltage

Wedeward, Kevin

197

Temperature-sensitive fluorescence of NaRETiO4:Pr3+ (RE = Y, Gd) based on the intervalence charge transfer between Pr3+ and Ti4+  

NASA Astrophysics Data System (ADS)

The temperature-dependent photoluminescence properties of efficient red-emitting phosphors NaYTiO4:Pr3+ and NaGdTiO4:Pr3+ are studied. Distinct temperature sensing characteristic of 1D2 emission is observed. The intensity of 1D2 emission is almost linearly decreased with the increasing temperature. The quenching process is induced by a low-lying Pr3+-Ti4+ intervalence charge transfer state (IVCT). Because the energies of IVCTs are different for two samples, different temperature sensitive ranges are observed.

Zhang, Su; Liang, Hongbin; Liu, Yufeng

2014-02-01

198

Linear Amplifier Model for Optomechanical Systems  

E-print Network

We model optomechanical systems as linear optical amplifiers. This provides a unified treatment of diverse optomechanical phenomena. We emphasize, in particular, the relationship between ponderomotive squeezing and optomechanically induced transparency, two foci of current research. We characterize the amplifier response to quantum and deliberately applied fluctuations, both optical and mechanical. Further, we apply these results to establish quantum limits on external force sensing both on and off cavity resonance. We find that the maximum sensitivity attained on resonance constitutes an absolute upper limit, not surpassed when detuning off cavity resonance. The theory can be extended to a two-sided cavity with losses and limited detection efficiency.

Thierry Botter; Daniel W. C. Brooks; Nathan Brahms; Sydney Schreppler; Dan M. Stamper-Kurn

2012-01-19

199

Charge Site Mass Spectra: Conformation-Sensitive Components of the Electron Capture Dissociation Spectrum of a Protein  

NASA Astrophysics Data System (ADS)

A conventional electron capture dissociation (ECD) spectrum of a protein is uniquely characteristic of the first dimension of its linear structure. This sequence information is indicated by summing the primary c m+ and z m+• products of cleavage at each of its molecular ion's inter-residue bonds. For example, the ECD spectra of ubiquitin (M + nH)n+ ions, n = 7-13, provide sequence characterization of 72 of its 75 cleavage sites from 1843 ions in seven c (1-7)+ and eight z (1-8)+• spectra and their respective complements. Now we find that each of these c/z spectra is itself composed of "charge site (CS)" spectra, the c m+ or z m+• products of electron capture at a specific protonated basic residue. This charge site has been H-bonded to multiple other residues, producing multiple precursor ion forms; ECD at these residues yields the multiple products of that CS spectrum. Closely similar CS spectra are often formed from a range of charge states of ubiquitin and KIX ions; this indicates a common secondary conformation, but not the conventional ?-helicity postulated previously. CS spectra should provide new capabilities for comparing regional conformations of gaseous protein ions and delineating ECD fragmentation pathways.

Skinner, Owen S.; Breuker, Kathrin; McLafferty, Fred W.

2013-06-01

200

Negative electrospray ionization on porous supporting tips for mass spectrometric analysis: electrostatic charging effect on detection sensitivity and its application to explosive detection.  

PubMed

The simplicity and easy manipulation of a porous substrate-based ESI-MS technique have been widely applied to the direct analysis of different types of samples in positive ion mode. However, the study and application of this technique in negative ion mode are sparse. A key challenge could be due to the ease of electrical discharge on supporting tips upon the application of negative voltage. The aim of this study is to investigate the effect of supporting materials, including polyester, polyethylene and wood, on the detection sensitivity of a porous substrate-based negative ESI-MS technique. By using nitrobenzene derivatives and nitrophenol derivatives as the target analytes, it was found that the hydrophobic materials (i.e., polyethylene and polyester) with a higher tendency to accumulate negative charge could enhance the detection sensitivity towards nitrobenzene derivatives via electron-capture ionization; whereas, compounds with electron affinities lower than the cut-off value (1.13 eV) were not detected. Nitrophenol derivatives with pKa smaller than 9.0 could be detected in the form of deprotonated ions; whereas polar materials (i.e., wood), which might undergo competitive deprotonation with the analytes, could suppress the detection sensitivity. With the investigation of the material effects on the detection sensitivity, the porous substrate-based negative ESI-MS method was developed and applied to the direct detection of two commonly encountered explosives in complex samples. PMID:24492411

Wong, Melody Yee-Man; Man, Sin-Heng; Che, Chi-Ming; Lau, Kai-Chung; Ng, Kwan-Ming

2014-03-21

201

Dispersive Readout of a Superconducting Qubit Using a SLUG Amplifier  

NASA Astrophysics Data System (ADS)

Developing a fast, high-fidelity readout of superconducting quantum bits (qubits) makes significant demands of the cryogenic amplification chain, where the first stage amplifier must have sufficient sensitivity to resolve the state of the qubit and enough gain to overcome the noise of subsequent stages of amplification. Additionally, the architecture of a scalable quantum computer requires an amplifier with a large enough bandwidth and dynamic range to simultaneously measure multiple qubits without sacrificing performance. In this thesis, we describe a novel low-noise phase-insensitive linear amplifier at microwave frequencies based on the Superconducting Low-Inductance Undulatory Galvanometer (SLUG), an amplifier capable of meeting the demands of the superconducting qubit community. We discuss the numerical optimization of the SLUG amplifier and calculate the expected amplifier gain and noise temperature. We walk through the amplifier design and fabrication process before discussing how to fully characterize the fabricated device. We report on amplifiers with measured gain of 10 to 15 dB, bandwidths from 50 to 100 MHz, and added system noise below 2 quanta. Next, we describe the qubit- cavity system and the limits of a dispersive quantum measurement using circuit quantum electrodynamics. Finally, we report on experiments where a SLUG amplifier is used to measure the state of a superconducting qubit, demonstrating improved measurement signal-to-noise ratios of 10 dB and a dynamic range that is an order of magnitude better than any available amplifier currently being developed.

Hover, David James

202

Analog Electronics: Basic Circuits of Operational Amplifiers  

NSDL National Science Digital Library

This site offers a set of interactive operational amplifiers (OAs) simulators with detailed lessons and basic circuit schematics (including theory). The Java applets provided include an inverting amplifier, summing amplifier, difference amplifier, differentiator, and integrator circuit amplifier.

2009-11-02

203

Super sensitization: grand charge (hole/electron) separation in ATC dye sensitized CdSe, CdSe/ZnS type-I, and CdSe/CdTe type-II core-shell quantum dots.  

PubMed

Ultrafast charge-transfer dynamics has been demonstrated in CdSe quantum dots (QD), CdSe/ZnS type-I core-shell, and CdSe/CdTe type-II core-shell nanocrystals after sensitizing the QD materials by aurin tricarboxylic acid (ATC), in which CdSe QD and ATC form a charge-transfer complex. Energy level diagrams suggest that the conduction and valence band of CdSe lies below the LUMO and the HOMO level of ATC, respectively, thus signifying that the photoexcited hole in CdSe can be transferred to ATC and that photoexcited ATC can inject electrons into CdSe QD, which has been confirmed by steady state and time-resolved luminescence studies and also by femtosecond time-resolved absorption measurements. The effect of shell materials (for both type-I and type-II) on charge-transfer processes has been demonstrated. Electron injection in all the systems were measured to be <150?fs. However, the hole transfer time varied from 900?fs to 6?ps depending on the type of materials. The hole-transfer process was found to be most efficient in CdSe QD. On the other hand, it has been found to be facilitated in CdSe/CdTe type-II and retarded in CdSe/ZnS type-I core-shell materials. Interestingly, electron injection from photoexcited ATC to both CdSe/CdTe type-II and CdSe/ZnS type-I core-shell has been found to be more efficient as compared to pure CdSe QD. Our observation suggests the potential of quantum dot core-shell super sensitizers for developing more efficient quantum dot solar cells. PMID:25179856

Debnath, Tushar; Maity, Partha; Ghosh, Hirendra N

2014-10-01

204

Laser amplifier and method  

DOEpatents

Laser amplifiers and methods for amplifying a laser beam are disclosed. A representative embodiment of the amplifier comprises first and second curved mirrors, a gain medium, a third mirror, and a mask. The gain medium is situated between the first and second curved mirrors at the focal point of each curved mirror. The first curved mirror directs and focuses a laser beam to pass through the gain medium to the second curved mirror which reflects and recollimates the laser beam. The gain medium amplifies and shapes the laser beam as the laser beam passes therethough. The third mirror reflects the laser beam, reflected from the second curved mirror, so that the laser beam bypasses the gain medium and return to the first curved mirror, thereby completing a cycle of a ring traversed by the laser beam. The mask defines at least one beam-clipping aperture through which the laser beam passes during a cycle. The gain medium is pumped, preferably using a suitable pumping laser. The laser amplifier can be used to increase the energy of continuous-wave or, especially, pulsed laser beams including pulses of femtosecond duration and relatively high pulse rate.

Backus, Sterling (Ann Arbor, MI); Kapteyn, Henry C. (Ann Arbor, MI); Murnane, Margaret M. (Ann Arbor, MI)

1997-01-01

205

Laser amplifier and method  

DOEpatents

Laser amplifiers and methods for amplifying a laser beam are disclosed. A representative embodiment of the amplifier comprises first and second curved mirrors, a gain medium, a third mirror, and a mask. The gain medium is situated between the first and second curved mirrors at the focal point of each curved mirror. The first curved mirror directs and focuses a laser beam to pass through the gain medium to the second curved mirror which reflects and recollimates the laser beam. The gain medium amplifies and shapes the laser beam as the laser beam passes therethrough. The third mirror reflects the laser beam, reflected from the second curved mirror, so that the laser beam bypasses the gain medium and return to the first curved mirror, thereby completing a cycle of a ring traversed by the laser beam. The mask defines at least one beam-clipping aperture through which the laser beam passes during a cycle. The gain medium is pumped, preferably using a suitable pumping laser. The laser amplifier can be used to increase the energy of continuous-wave or, especially, pulsed laser beams including pulses of femtosecond duration and relatively high pulse rate. 7 figs.

Backus, S.; Kapteyn, H.C.; Murnane, M.M.

1997-07-01

206

SLUG Microwave Amplifier: Theory  

E-print Network

We describe a novel scheme for low-noise phase-insensitive linear amplification at microwave frequencies based on the Superconducting Low-inductance Undulatory Galvanometer (SLUG). Direct integration of the junction equations of motion provides access to the full scattering matrix of the SLUG. We discuss the optimization of SLUG amplifiers and calculate amplifier gain and noise temperature in both the thermal and quantum regimes. Loading of the SLUG element by the finite input admittance is taken into account, and strategies for decoupling the SLUG from the higher-order modes of the input circuit are discussed. The microwave SLUG amplifier is expected to achieve noise performance approaching the standard quantum limit in the frequency range from 5-10 GHz, with gain around 15 dB for a single-stage device and instantaneous bandwidths of order 1 GHz.

Ribeill, G J; Chen, Y -F; Zhu, S; McDermott, R

2011-01-01

207

Universal signal conditioning amplifier  

NASA Technical Reports Server (NTRS)

Engineers at NASA's Kennedy Space Center have designed a signal conditioning amplifier which automatically matches itself to almost any kind of transducer. The product, called Universal Signal Conditioning Amplifier (USCA), uses state-of-the-art technologies to deliver high accuracy measurements. USCA's features which can be either programmable or automated include: voltage, current, or pulsed excitation, unlimited resolution gain, digital filtering and both analog and digital output. USCA will be used at Kennedy Space Center's launch pads for environmental measurements such as vibrations, strains, temperatures and overpressures. USCA is presently being commercialized through a co-funded agreement between NASA, the State of Florida, and Loral Test and Information Systems, Inc.

Larson, William E.; Hallberg, Carl; Medelius, Pedro J.

1994-01-01

208

Highly sensitive and positively charged precolumn derivatization reagent for amines and amino acids in liquid chromatography/electrospray ionization tandem mass spectrometry.  

PubMed

We have developed a highly sensitive and positively charged precolumn derivatization reagent, (5-N-succinimidoxy-5-oxopentyl)triphenylphosphonium bromide (SPTPP), for amines and amino acids in liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS). The handling of the derivatization reaction is quite simple and the reagent reacts with the analytes rapidly and with high efficiency. The derivatized analytes were observed to form regular and intense product ions upon MS/MS analysis; thus, highly sensitive and selective detection was possible in the selected reaction monitoring (SRM) mode. The limits of detection of the SPTPP-derivatized analytes were less than sub-femtomole levels. The sensitivities of the derivatized analytes increased about 500-fold compared to those of underivatized analytes. Since the hydrophobicities of the samples increased after their derivatization, the resolution of the analytes improved dramatically when a reversed-phase system was used. The relative standard deviations of intra-day and inter-day variations were below 10.6% and 13.3%, respectively. The accuracy ranged between 86.6-113% and 83.4-113%, respectively. Furthermore, the developed reagent was used for the analysis of the neurotransmitter 4-aminobutanoic acid (GABA) and oxidative stress markers such as oxidized, nitrated, and halogenated tyrosines in rat serum. PMID:20391609

Inagaki, Shinsuke; Tano, Yuma; Yamakata, Yusuke; Higashi, Tatsuya; Min, Jun Zhe; Toyo'oka, Toshimasa

2010-05-15

209

Novel sulfur-doped niobium pentoxide nanoparticles: fabrication, characterization, visible light sensitization and redox charge transfer study  

Microsoft Academic Search

Novel sulfur-modified niobium(V) oxide nanoparticles (SNON) that firstly exhibited good visible light sensitization were fabricated\\u000a by a modified sol–gel technique using a very stable sol containing niobium(V) chloride, oxalic acid, isopropanol as chelating\\u000a agent and thiourea as sulfur source. The resulting S-doped Nb2O5 nanomaterials were characterized by cyclic voltammetry (CV), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy\\u000a (EDAX), scanning electron microscope

Mohammad Hossein Habibi; Reza Mokhtari

210

Charged Leptons  

E-print Network

This is the report of the Intensity Frontier Charged Lepton Working Group of the 2013 Community Summer Study "Snowmass on the Mississippi", summarizing the current status and future experimental opportunities in muon and tau lepton studies and their sensitivity to new physics. These include searches for charged lepton flavor violation, measurements of magnetic and electric dipole moments, and precision measurements of the decay spectrum and parity-violating asymmetries.

Albrecht, J; Babu, K; Bernstein, R H; Blum, T; Brown, D N; Casey, B C K; Cheng, C -h; Cirigliano, V; Cohen, A; Deshpande, A; Dukes, E C; Echenard, B; Gaponenko, A; Glenzinski, D; Gonzalez-Alonso, M; Grancagnolo, F; Grossman, Y; Harnik, R; Hitlin, D G; Kiburg, B; Knoepfe, K; Kumar, K; Lim, G; Lu, Z -T; McKeen, D; Miller, J P; Ramsey-Musolf, M; Ray, R; Roberts, B L; Rominsky, M; Semertzidis, Y; Stoeckinger, D; Talman, R; Van De Water, R; Winter, P

2013-01-01

211

Fourier plane image amplifier  

DOEpatents

A solid state laser is frequency tripled to 0.3 .mu.m. A small portion of the laser is split off and generates a Stokes seed in a low power oscillator. The low power output passes through a mask with the appropriate hole pattern. Meanwhile, the bulk of the laser output is focused into a larger stimulated Brillouin scattering (SBS) amplifier. The low power beam is directed through the same cell in the opposite direction. The majority of the amplification takes place at the focus which is the fourier transform plane of the mask image. The small holes occupy large area at the focus and thus are preferentially amplified. The amplified output is now imaged onto the multichip module where the holes are drilled. Because of the fourier plane amplifier, only .about.1/10th the power of a competitive system is needed. This concept allows less expensive masks to be used in the process and requires much less laser power.

Hackel, Lloyd A. (Livermore, CA); Hermann, Mark R. (San Ramon, CA); Dane, C. Brent (Livermore, CA); Tiszauer, Detlev H. (Tracy, CA)

1995-01-01

212

Fourier plane image amplifier  

DOEpatents

A solid state laser is frequency tripled to 0.3 {micro}m. A small portion of the laser is split off and generates a Stokes seed in a low power oscillator. The low power output passes through a mask with the appropriate hole pattern. Meanwhile, the bulk of the laser output is focused into a larger stimulated Brillouin scattering (SBS) amplifier. The low power beam is directed through the same cell in the opposite direction. The majority of the amplification takes place at the focus which is the fourier transform plane of the mask image. The small holes occupy large area at the focus and thus are preferentially amplified. The amplified output is now imaged onto the multichip module where the holes are drilled. Because of the fourier plane amplifier, only about 1/10th the power of a competitive system is needed. This concept allows less expensive masks to be used in the process and requires much less laser power. 1 fig.

Hackel, L.A.; Hermann, M.R.; Dane, C.B.; Tiszauer, D.H.

1995-12-12

213

Multipass amplifiers of POLARIS  

NASA Astrophysics Data System (ADS)

Advanced high intensity laser matter interaction experiments always call for optimized laser performance. In order to further enhance the POLARIS laser system, operational at the University of Jena and the Helmholtz-Institute Jena, in particular its energy, bandwidth and focusability, new amplifier technologies have been developed and are reported here. Additionally, existing sections were considerably improved. A new multi-pass amplification stage, which is able to replace two currently used ones, was developed in close collaboration with the MPQ (Garching). The new basic elements of this amplifier are well homogenized pump modules and the application of a successive imaging principle. By operating the amplifier under vacuum conditions a top hat beam profile with an output energy of up to 1.5 J per pulse is foreseen. The already implemented POLARIS amplifier A4 was further improved by adapting an advanced method for the homogenization of the multi-spot composed pump profile. The new method comprises a computer-based evolutionary algorithm which optimizes the position of the different spots regarding its individual size, shape and intensity. The latter allowed a better homogenization of the POLARIS near field profile.

Keppler, S.; Wandt, C.; Hornung, M.; Bödefeld, R.; Kessler, A.; Sävert, A.; Hellwing, M.; Schorcht, F.; Hein, J.; Kaluza, M. C.

2013-05-01

214

Study of the sensitivity of neutron sensors consisting of a converter plus Si charged-particle detector  

NASA Astrophysics Data System (ADS)

With the aim of improving neutron sensors for monitoring external neutron exposure, we have analysed the workings of a converter plus silicon PIN diode detector arrangement. A phenomenological analysis of the conversion and signal generation of different converter materials and their effectiveness is given. The results are compared with experimental measurements. Because of the fundamentally different interactions of thermal neutrons versus high energy neutrons, we study the two species separately. For thermal neutrons, two types of neutron converters were examined, 6LiF (crystalline) and Kodak 10B films. For fast neutrons in the energy range from 1 to 20 MeV hydrogen rich Lucite—PMMA (H 8C 5O 2) and Polyethylene—PE (CH 2) converters were studied. For thermal neutrons and a pure 10B-converter the theoretical response in counts/neutron reaches a value of BS TOT=0.0684 and for a pure 6LiF-converter LiFS TOT=0.0543 . The corresponding experimental responses are 0.0062 for KODAK 10B film and 0.0223 for 6LiF converters. The difference between theory and experiment is understood by the necessity to use a lower level discriminator to eliminate unwanted counts coming from electrons and gammas. In the case of the 10B converter impurities in the converter material reduce the signal. Our analysis for fast neutrons allows us to calculate the ratio of sensitivity for Polyethylene to Lucite, for which we predict a value of 1.6. For the measured sensitivities for PE and PMMA, using an 241Am-Be neutron source, we obtain the values of 0.00225 and 0.0015 respectively, the ratio being 1.5.

Wielunski, M.; Schütz, R.; Fantuzzi, E.; Pagnamenta, A.; Wahl, W.; Palfįlvi, J.; Zombori, P.; Andrasi, A.; Stadtmann, H.; Schmitzer, Ch.

2004-01-01

215

Molecular engineering of simple phenothiazine-based dyes to modulate dye aggregation, charge recombination, and dye regeneration in highly efficient dye-sensitized solar cells.  

PubMed

A series of simple phenothiazine-based dyes, namely, TP, EP, TTP, ETP, and EEP have been developed, in which the thiophene (T), ethylenedioxythiophene (E), their dimers, and mixtures are present to modulate dye aggregation, charge recombination, and dye regeneration for highly efficient dye-sensitized solar cell (DSSC) applications. Devices sensitized by the dyes TP and TTP display high power conversion efficiencies (PCEs) of 8.07 (Jsc = 15.2?mA?cm(-2), Voc =0.783?V, fill factor (FF) = 0.679) and 7.87?% (Jsc = 16.1?mA?cm(-2), Voc = 0.717?V, FF = 0.681), respectively; these were measured under simulated AM 1.5 sunlight in conjunction with the I(-)/I3(-) redox couple. By replacing the T group with the E unit, EP-based DSSCs had a slightly lower PCE of 7.98?% with a higher short-circuit photocurrent (Jsc) of 16.7?mA?cm(-2). The dye ETP, with a mixture of E and T, had an even lower PCE of 5.62?%. Specifically, the cell based on the dye EEP, with a dimer of E, had inferior Jsc and Voc values and corresponded to the lowest PCE of 2.24?%. The results indicate that the photovoltaic performance can be finely modulated through structural engineering of the dyes. The selection of T analogues as donors can not only modulate light absorption and energy levels, but also have an impact on dye aggregation and interfacial charge recombination of electrons at the interface of titania, electrolytes, and/or oxidized dye molecules; this was demonstrated through DFT calculations, electrochemical impedance analysis, and transient photovoltage studies. PMID:24715494

Hua, Yong; Chang, Shuai; He, Jian; Zhang, Caishun; Zhao, Jianzhang; Chen, Tao; Wong, Wai-Yeung; Wong, Wai-Kwok; Zhu, Xunjin

2014-05-19

216

RF Power Amplifiers for Cellphones  

Microsoft Academic Search

A wide variety of semiconductor devices are used in wireless power amplifiers. The RF performance and other attributes of cellphone RF power amplifiers using Si and GaAs based technologies will be reviewed and compared.

C. E. Weitzel

217

Highly efficient ZnO/Au Schottky barrier dye-sensitized solar cells: Role of gold nanoparticles on the charge-transfer process  

PubMed Central

Summary Zinc oxide (ZnO) nanorods decorated with gold (Au) nanoparticles have been synthesized and used to fabricate dye-sensitized solar cells (DSSC). The picosecond-resolved, time-correlated single-photon-count (TCSPC) spectroscopy technique was used to explore the charge-transfer mechanism in the ZnO/Au-nanocomposite DSSC. Due to the formation of the Schottky barrier at the ZnO/Au interface and the higher optical absorptions of the ZnO/Au photoelectrodes arising from the surface plasmon absorption of the Au nanoparticles, enhanced power-conversion efficiency (PCE) of 6.49% for small-area (0.1 cm2) ZnO/Au-nanocomposite DSSC was achieved compared to the 5.34% efficiency of the bare ZnO nanorod DSSC. The TCSPC studies revealed similar dynamics for the charge transfer from dye molecules to ZnO both in the presence and absence of Au nanoparticles. A slower fluorescence decay associated with the electron recombination process, observed in the presence of Au nanoparticles, confirmed the blocking of the electron transfer from ZnO back to the dye or electrolyte by the Schottky barrier formed at the ZnO/Au interface. For large area DSSC (1 cm2), ~130% enhancement in PCE (from 0.50% to 1.16%) was achieved after incorporation of the Au nanoparticles into the ZnO nanorods. PMID:22043457

Bora, Tanujjal; Kyaw, Htet H; Sarkar, Soumik; Pal, Samir K

2011-01-01

218

Rapid charge-transfer in polypyrrole-single wall carbon nanotube complex counter electrodes: Improved photovoltaic performances of dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Dye-sensitized solar cell (DSSC) is a promising solution to global energy and environmental problems because of its clean, high efficiency, good durability, and easy fabrication. However, enhancement of power conversion efficiency and high cost of Pt counter electrode are still significant issues in commercial application of DSSCs. Herein, pyrrole-single wall nanotube (pyrrole-SWCNT) complexes are pioneerly synthesized by a reflux technique and subsequently in-situ polymerized and employed as counter electrodes (CEs) for DSSCs. Different from traditional polypyrrole/SWCNT (PPy/SWCNT) composites, the resultant PPy-SWCNT complexes are expected to fulfill the good electrical-conduction of SWCNT and electrocatalytic behaviors of PPy in accelerating electrochemical activity and charge transfer owing to the covalent bond between PPy (N atoms) and SWCNT (C atoms). The DSSCs employing PPy-SWCNT complex CEs exhibit significantly enhanced photovoltaic performances, in which a promising power conversion efficiency of 8.30% is obtained from PPy-2 wt‰ SWCNT complex CE in comparison with 6.31% from PPy-only CE. The high conversion efficiency, rapid charge-transfer in combination with simple preparation, relatively low cost, and scalability demonstrates the potential use of PPy-SWCNT complexes in robust DSSCs.

He, Benlin; Tang, Qunwei; Luo, Jinghuan; Li, Qinghua; Chen, Xiaoxu; Cai, Hongyuan

2014-06-01

219

Gas amplified ionization detector for gas chromatography  

SciTech Connect

A gas-amplified ionization detector for gas chromatography which possesses increased sensitivity and a very fast response time is described. Solutes eluding from a gas chromatographic column are ionized by uv photoionization of matter eluting therefrom. The detector is capable of generating easily measured voltage signals by gas amplification/multiplication of electron products resulting from the uv photoionization of at least a portion of each solute passing through the detector. 4 figs.

Huston, G.C.

1989-11-27

220

Gas amplified ionization detector for gas chromatography  

DOEpatents

A gas-amplified ionization detector for gas chromatrography which possesses increased sensitivity and a very fast response time. Solutes eluding from a gas chromatographic column are ionized by UV photoionization of matter eluting therefrom. The detector is capable of generating easily measured voltage signals by gas amplification/multiplication of electron products resulting from the UV photoionization of at least a portion of each solute passing through the detector.

Huston, Gregg C. (LaBelle, PA)

1992-01-01

221

Current vs. Voltage Feedback Amplifiers  

E-print Network

Current vs. Voltage Feedback Amplifiers One question continuously troubles the analog design engi- neer: 'Which amplifier topology is better for my application, current feedback or voltage feedback) are not apparent. Today's CFB and VFB amplifiers have comparable performance, but there are cer- tain unique

Lanterman, Aaron

222

Differential Amplifier for use with  

E-print Network

Differential Amplifier for use with Attenuated Probes Clint Sprott December 17, 1964 University of Wisconsin Thermonuclear Plasma Studies PLP 43 Copy No. 3, #12;Introduction: Differential Amplifier for use a factor of ten. Using the probe shown in Fig. 1 and the cathode follower amplifier circuit shown in Fig. 3

Sprott, Julien Clinton

223

Improved-Bandwidth Transimpedance Amplifier  

NASA Technical Reports Server (NTRS)

The widest available operational amplifier, with the best voltage and current noise characteristics, is considered for transimpedance amplifier (TIA) applications where wide bandwidth is required to handle fast rising input signals (as for time-of-flight measurement cases). The added amplifier inside the TIA feedback loop can be configured to have slightly lower voltage gain than the bandwidth reduction factor.

Chapsky, Jacob

2009-01-01

224

Implementation of a preamplifier-amplifier system for radiation detectors used in Mössbauer spectroscopy  

NASA Astrophysics Data System (ADS)

We report the assembly and testing of a preamplification and amplification system for pulses produced by gaseous radiation detectors commonly used in Mössbauer spectroscopy. The system is composed by a pair of commercial integrated circuits A203 and A206, which operate as charge sensitive preamplifier-shaping amplifier and linear amplifier-low level discriminator, respectively. The integrated circuits were interconnected in the unipolar output mode and placed inside a metallic shielding, which prevents noise amplification for a suitable signal-noise ratio. The system was tested by irradiating a proportional counter LND-45431 with characteristic X rays of 6.3 keV and gamma rays of 14.4 keV emitted by a Mössbauer radioactive source of 57Co (Rh). Unipolar pulses with Gaussian profile were obtained at the output of the linear amplifier, whose amplitudes were close to 0.4 V for 6.3 keV X rays and 1.4 V for 14.4 keV gamma rays. Pulse height spectra showed that the system allows a satisfactory identification of the X-rays and gamma rays emitted by the 57Co source, giving the possibility to make a good selection of the 14.4 keV peak for having a suitable signal-noise ratio in the Mössbauer spectra. Absorption percentages of 14 % were found by taking the Mössbauer spectra of a natural iron absorber. The assembly and tests of the system are presented through this paper.

Velįsquez, A. A.; Arroyave, M.

2014-01-01

225

Amplifying genetic logic gates.  

PubMed

Organisms must process information encoded via developmental and environmental signals to survive and reproduce. Researchers have also engineered synthetic genetic logic to realize simpler, independent control of biological processes. We developed a three-terminal device architecture, termed the transcriptor, that uses bacteriophage serine integrases to control the flow of RNA polymerase along DNA. Integrase-mediated inversion or deletion of DNA encoding transcription terminators or a promoter modulates transcription rates. We realized permanent amplifying AND, NAND, OR, XOR, NOR, and XNOR gates actuated across common control signal ranges and sequential logic supporting autonomous cell-cell communication of DNA encoding distinct logic-gate states. The single-layer digital logic architecture developed here enables engineering of amplifying logic gates to control transcription rates within and across diverse organisms. PMID:23539178

Bonnet, Jerome; Yin, Peter; Ortiz, Monica E; Subsoontorn, Pakpoom; Endy, Drew

2013-05-01

226

Monolithic dye laser amplifier  

DOEpatents

A fluid dye laser amplifier for amplifying a dye beam by pump beams has a channel structure defining a channel through which a laseable fluid flows and the dye and pump beams pass transversely to one another through a lasing region. The channel structure is formed with two pairs of mutually spaced-apart and mutually confronting glass windows, which are interlocked and make surface-contacts with one another and surround the lasing region. One of the glass window pairs passes the dye beam and the other passes the pump beams therethrough and through the lasing region. Where these glass window pieces make surface-contacts, glue is used to join the pieces together to form a monolithic structure so as to prevent the dye in the fluid passing through the channel from entering the space between the mutually contacting glass window pieces.

Kuklo, T.C.

1993-03-30

227

Monolithic dye laser amplifier  

DOEpatents

A fluid dye laser amplifier for amplifying a dye beam by pump beams has a channel structure defining a channel through which a laseable fluid flows and the dye and pump beams pass transversely to one another through a lasing region. The channel structure is formed with two pairs of mutually spaced-apart and mutually confronting glass windows, which are interlocked and make surface-contacts with one another and surround the lasing region. One of the glass window pairs passes the dye beam and the other passes the pump beams therethrough and through the lasing region. Where these glass window pieces make surface-contacts, glue is used to join the pieces together to form a monolithic structure so as to prevent the dye in the fluid passing through the channel from entering the space between the mutually contacting glass window pieces.

Kuklo, Thomas C. (Ripon, CA)

1993-01-01

228

Helical Fiber Amplifier  

DOEpatents

A multi-mode gain fiber is provided which affords substantial improvements in the maximum pulse energy, peak power handling capabilities, average output power, and/or pumping efficiency of fiber amplifier and laser sources while maintaining good beam quality (comparable to that of a conventional single-mode fiber source). These benefits are realized by coiling the multimode gain fiber to induce significant bend loss for all but the lowest-order mode(s).

Koplow, Jeffrey P. (Washington, DC); Kliner, Dahy (San Ramon, CA); Goldberg, Lew (Fairfax, VA)

2002-12-17

229

Effective amplifier noise for an optical receiver based on linear mode avalanche photodiodes  

NASA Technical Reports Server (NTRS)

The rms noise charge induced by the amplifier for an optical receiver based on the linear-mode avalanche photodiode (APD) was analyzed. It is shown that for an amplifier with a 1-pF capacitor and a noise temperature of 100 K, the rms noise charge due to the amplifier is about 300. Since the noise charge must be small compared to the signal gain, APD gains on the order of 1000 will be required to operate the receiver in the linear mode.

Chen, C.-C.

1989-01-01

230

Dye-sensitized solar cells employing doubly or singly open-ended TiO2 nanotube arrays: structural geometry and charge transport.  

PubMed

We systematically investigated the charge transport properties of doubly or singly open-ended TiO2 nanotube arrays (DNT and SNT, respectively) for their utility as electrodes in dye-sensitized solar cells (DSCs). The SNT or DNT arrays were transferred in a bottom-up (B-up) or top-up (T-up) configuration onto a fluorine-doped tin oxide (FTO) substrate onto which had been deposited a 2 ?m thick TiO2 nanoparticle (NP) interlayer. This process yielded four types of DSCs prepared with SNTs (B-up or T-up) or DNT (B-up or T-up). The photovoltaic performances of these DSCs were analyzed by measuring the dependence of the charge transport on the DSC geometry. High resolution scanning electron microscopy techniques were used to characterize the electrode cross sections, and electrochemical impedance spectroscopy was used to characterize the electrical connection at the interface between the NT array and the TiO2 NP interlayer. We examined the effects of decorating the DNT or SNT arrays with small NPs (sNP@DNT and sNP@SNT, respectively) in an effort to increase the extent of dye loading. The DNT arrays decorated with small NPs performed better than the decorated SNT arrays, most likely because the Ti(OH)4 precursor solution flowed freely into the array through the open ends of the NTs in the DNT case but not in the SNT case. The sNP@DNT-based DSC exhibited a better PCE (10%) compared to the sNP@SNT-based DSCs (6.8%) because the electrolyte solution flow was not restricted, direct electron transport though the NT arrays was possible, the electrical connection at the interface between the NT array and the TiO2 NP interlayer was good, and the array provided efficient light harvesting. PMID:25136743

Choi, Jongmin; Song, Seulki; Kang, Gyeongho; Park, Taiho

2014-09-10

231

Minimum Charge Detection Using Selected Tunnel Diodes and Charge Multiplying Semiconductors  

Microsoft Academic Search

The charge multiplying semiconductor detector has unique characteristics as a charge amplifier in a circuit containing a tunnel diode biased for charge detection. The relationship between the tunnel diode junction capacitance and switching speed to the electrical parameters of the multiplying detector will be discussed for minimum charge detection. Experimental data will be presented for an instrument using these principles

Robert J. Locker

1966-01-01

232

Method and apparatus for providing pulse pile-up correction in charge quantizing radiation detection systems  

DOEpatents

A radiation detection method and system for continuously correcting the quantization of detected charge during pulse pile-up conditions. Charge pulses from a radiation detector responsive to the energy of detected radiation events are converted to voltage pulses of predetermined shape whose peak amplitudes are proportional to the quantity of charge of each corresponding detected event by means of a charge-sensitive preamplifier. These peak amplitudes are sampled and stored sequentially in accordance with their respective times of occurrence. Based on the stored peak amplitudes and times of occurrence, a correction factor is generated which represents the fraction of a previous pulses influence on a preceding pulse peak amplitude. This correction factor is subtracted from the following pulse amplitude in a summing amplifier whose output then represents the corrected charge quantity measurement.

Britton, Jr., Charles L. (Alcoa, TN); Wintenberg, Alan L. (Knoxville, TN)

1993-01-01

233

3-D TiO2 nanoparticle/ITO nanowire nanocomposite antenna for efficient charge collection in solid state dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

TiO2 nanoparticle (NP)/ITO nanowire (NW) nanocomposites for use as photoelectrode materials were fabricated to improve the charge collection efficiency in solid state dye sensitized solar cells (ss-DSSCs). The average current density for ss-DSSCs containing TiO2 NP/ITO NW arrays was 7.2 mA cm-2 that was 98% higher than that for the conventional TiO2 NP ss-DSSCs. The intensity modulated photocurrent spectroscopy (IMPS) and intensity modulated photovoltage spectroscopy (IMVS) studies exhibited that the electron diffusion length of TiO2 NP/ITO-NW nanocomposite ss-DSSCs was in the range of 4.3-5.6 ?m, longer than that of TiO2 NP solar cells (2.6-4.1 ?m). The longer diffusion length was responsible for the boosted current densities of TiO2 NP/ITO NW nanocomposite ss-DSSCs. We also employed the TiO2 NP/ITO NW nanocomposite photoelectrode to inorganic-organic perovskite solar cells whose energy conversion efficiency was 7.5%.TiO2 nanoparticle (NP)/ITO nanowire (NW) nanocomposites for use as photoelectrode materials were fabricated to improve the charge collection efficiency in solid state dye sensitized solar cells (ss-DSSCs). The average current density for ss-DSSCs containing TiO2 NP/ITO NW arrays was 7.2 mA cm-2 that was 98% higher than that for the conventional TiO2 NP ss-DSSCs. The intensity modulated photocurrent spectroscopy (IMPS) and intensity modulated photovoltage spectroscopy (IMVS) studies exhibited that the electron diffusion length of TiO2 NP/ITO-NW nanocomposite ss-DSSCs was in the range of 4.3-5.6 ?m, longer than that of TiO2 NP solar cells (2.6-4.1 ?m). The longer diffusion length was responsible for the boosted current densities of TiO2 NP/ITO NW nanocomposite ss-DSSCs. We also employed the TiO2 NP/ITO NW nanocomposite photoelectrode to inorganic-organic perovskite solar cells whose energy conversion efficiency was 7.5%. Electronic supplementary information (ESI) available: SEM images of a 3-D TiO2 nanoparticle (NP)/ITO nanowire (NW) nanocomposite photoelectrode, photovoltaic properties, J-V curves for the best performance cells, and the plot of dye loading vs. active layer thickness. See DOI: 10.1039/c4nr00621f

Han, Gill Sang; Lee, Sangwook; Noh, Jun Hong; Chung, Hyun Suk; Park, Jong Hoon; Swain, Bhabani Sankar; Im, Jeong-Hyeok; Park, Nam-Gyu; Jung, Hyun Suk

2014-05-01

234

Amplifying Electrochemical Indicators  

NASA Technical Reports Server (NTRS)

Dendrimeric reporter compounds have been invented for use in sensing and amplifying electrochemical signals from molecular recognition events that involve many chemical and biological entities. These reporter compounds can be formulated to target specific molecules or molecular recognition events. They can also be formulated to be, variously, hydrophilic or amphiphilic so that they are suitable for use at interfaces between (1) aqueous solutions and (2) electrodes connected to external signal-processing electronic circuits. The invention of these reporter compounds is expected to enable the development of highly miniaturized, low-power-consumption, relatively inexpensive, mass-producible sensor units for diverse applications.

Fan, Wenhong; Li, Jun; Han, Jie

2004-01-01

235

Universal Signal Conditioning Amplifier  

NASA Technical Reports Server (NTRS)

The Technological Research and Development Authority (TRDA) and NASA-KSC entered into a cooperative agreement in March of 1994 to achieve the utilization and commercialization of a technology development for benefiting both the Space Program and U.S. industry on a "dual-use basis". The technology involved in this transfer is a new, unique Universal Conditioning Amplifier (USCA) used in connection with various types of transducers. The project was initiated in partnership with I-Net Corporation, Lockheed Martin Telemetry & Instrumentation (formerly Loral Test and Information Systems) and Brevard Community College. The project consists of designing, miniaturizing, manufacturing, and testing an existing prototype of USCA that was developed for NASA-KSC by the I-Net Corporation. The USCA is a rugged and field-installable self (or remotely)- programmable amplifier that works in combination with a tag random access memory (RAM) attached to various types of transducers. This summary report comprises performance evaluations, TRDA partnership tasks, a project summary, project milestones and results.

Kinney, Frank

1997-01-01

236

Pulsed laser deposited porous nano-carpets of indium tin oxide and their use as charge collectors in core-shell structures for dye sensitized solar cells.  

PubMed

Porous In2O3:Sn (ITO) films resembling from brush carpets to open moss-like discrete nanostructures were grown by pulsed laser deposition under low to high background gas pressures, respectively. The charge transport properties of these mesoporous substrates were probed by pulsed laser photo-current and -voltage transient measurements in N719 dye sensitized devices. Although the cyclic voltammetry and dye adsorption measurements suggest a lower proportion of electro-active dye molecules for films deposited at the high-end background gas pressures, the transient measurements indicate similar electron transport rates within the films. Solar cell operation was achieved by the deposition of a conformal TiO2 shell layer by atomic layer deposition (ALD). Much of the device improvement was shown to be due to the TiO2 shell blocking the recombination of photoelectrons with the electrolyte as recombination lifetimes increased drastically from a few seconds in uncoated ITO to over 50 minutes in the ITO with a TiO2 shell layer. Additionally, an order of magnitude increase in the electron transport rate in ITO/TiO2 (core/shell) films was observed, giving the core-shell structure a superior ratio of recombination/transport times. PMID:25563519

Garvey, Timothy R; Farnum, Byron H; Lopez, Rene

2015-01-28

237

Ultrathin SnO2 scaffolds for TiO2-based heterojunction photoanodes in dye-sensitized solar cells: oriented charge transport and improved light scattering.  

PubMed

In this paper, band-structure matching strategy of a TiO2-based heterojunction within which electrons can be collected from TiO2 nanoparticles and transported rapidly in the bulk structure is reported. On the basis of the band-structure analysis of different TiO2-based heterostructures, focus was directed to the SnO2 nanosheet because of its appropriate band position and high electrical conductivity. Through a systematic investigation of the incorporation of ultrathin SnO2 nanosheet scaffolds for TiO2-based photoanodes in dye-sensitized solar cells (DSCs), we propose an anisotropy "constrained random walk" model to describe the controlled electron transit process. In this system, electrons are transferred orientedly overall, as well as randomly locally, leading to a significant reduction in the charge diffusion route compared to the conventional isotropic "random walk" model. In brief, the 2D ultrathin nanosheets provide rapid transit pathways and improved light-scattering centers, which can ensure a sufficient amount of dye loading and slow recombination. An overall light-to-electricity conversion efficiency as high as 8.25% is achieved by embedding the appropriate amount of SnO2 scaffold in a TiO2-based photoanode. PMID:23733334

Yang, Shuang; Hou, Yu; Xing, Jun; Zhang, Bo; Tian, Feng; Yang, Xiao Hua; Yang, Hua Gui

2013-07-01

238

TiO2 nanorods: a facile size- and shape-tunable synthesis and effective improvement of charge collection kinetics for dye-sensitized solar cells.  

PubMed

In this paper, we present a novel, high-yield, and cost-effective hydrothermal method for the preparation of single crystal-like anatase TiO2 nanorods (NRs) with specific {101} exposed crystal planes and preferred [001] growth direction, which is governed by the "oriented attachment" mechanism. The successful synthesis of TiO2 NRs and fine tuning on their size and shape could be easily accomplished by adjusting the solvent compositions. The salient feature of these NRs, in lieu of traditional nanoparticles as building blocks of photoanodes in dye-sensitized solar cell (DSSC) system, rests with their significantly reduced grain boundaries. The electron diffusion and recombination kinetics have been critically compared for the first time with respect to the size and shape of the novel building blocks. A high efficiency of 8.87% has finally been achieved for DSSC based on long-thin NRs rather than short-thin or long-thick NRs, which possesses balanced optimizations on charge collection and light-harvesting properties. PMID:24833257

Zhang, Wenjun; Xie, Yan; Xiong, Dehua; Zeng, Xianwei; Li, Zhihong; Wang, Mingkui; Cheng, Yi-Bing; Chen, Wei; Yan, Keyou; Yang, Shihe

2014-06-25

239

Reflex ring laser amplifier system  

DOEpatents

A laser pulse is injected into an unstable ring resonator-amplifier structure. Inside this resonator the laser pulse is amplified, spatially filtered and magnified. The laser pulse is recirculated in the resonator, being amplified, filtered and magnified on each pass. The magnification is chosen so that the beam passes through the amplifier in concentric non-overlapping regions similar to a single pass MOPA. After a number of passes around the ring resonator the laser pulse is spatially large enough to exit the ring resonator system by passing around an output mirror.

Summers, Mark A. (Livermore, CA)

1985-01-01

240

Optical Amplifier for Space Applications  

NASA Technical Reports Server (NTRS)

We describe an optical amplifier designed to amplify a spatially sampled component of an optical wavefront to kilowatt average power. The goal is means for implementing a strategy of spatially segmenting a large aperture wavefront, amplifying the individual segments, maintaining the phase coherence of the segments by active means, and imaging the resultant amplified coherent field. Applications of interest are the transmission of space solar power over multi-megameter distances, as to distant spacecraft, or to remote sites with no preexisting power grid.

Fork, Richard L.; Cole, Spencer T.; Gamble, Lisa J.; Diffey, William M.; Keys, Andrew S.

1999-01-01

241

Zero-Net-Charge Air Ionizer  

NASA Technical Reports Server (NTRS)

Instrument monitors air supplied by air ionizer and regulates ionizer to ensure net charge neutral. High-impedance electrometer and nulling control amplifier regulate output of air ionizer. Primarily intended to furnish ionized air having no net charge, instrument adaptable to generating air with positive or negative net charge is so desired. Useful where integrated circuit chips are manufactured, inspected, tested or assembled.

Woods, W. R., Jr.

1985-01-01

242

In-situ experimental investigations of electron space-charge instabilities and noise mechanisms in a reentrant crossed-field amplifier via distributed-cathode emission and gated-beam injection  

SciTech Connect

Experimental investigations of the true physical conditions inside the crossed-field devices are of fundamental importance for the understanding of the operation of these devices and may lead to eventual improvement of the present tubes. At Northeastern University, tube research has taken up a combined approach of in situ plasma diagnostics and computer simulation using two frequency scaled CFA`s as test vehicles. A collection of temporal and time-averaged diagnostic techniques have been developed through the research. Probe measurements as well as device performance of the linear CFA and the beam-injected, reentrant CFA have been directly compared with computer simulation results from MASK and NEAMP codes. The authors have recently incorporated in their reentrant CFA a secondary emission cathode for the purpose of gaining insight on improving the noise performance of both military and commercial devices. It has long been speculated, and appears more so as a result of the improved diagnostic techniques, that the instabilities in the space charge cloud are the major source of noise in crossed-field devices. Long electron transit time facilitates large-scale energy exchanges between hub electrons and eliminates the condition for the classical Brillouin flow. Their time-averaged density measurements confirmed that electron cloud extends beyond that predicted by the classical theory; preliminary observations showed organized space charge oscillations for static operating regimes. These oscillations can interact with the applied RF drive signal at different levels resulting in noise on the RF circuit. Other instabilities associated with the cathode secondary emission and due to reentrant electrons are, among other factors, evaluated in terms of their contribution to the turbulent behavior via spatial probes that monitor the anode current, back bombardment current and space charge fluctuation.

Ye, J.Z.; MacGregor, R.; Chan, C.; Ruden, T.E. [Northeastern Univ., Boston, MA (United States)

1995-12-31

243

The microstrip SQUID amplifier  

NASA Astrophysics Data System (ADS)

A Superconducting Quantum Interference Devices (SQUIDS) can operate at frequencies up to several GHz and can be cooled to less than 100 mK. Such characteristics make the SQUID---a flux-to-voltage transducer---an excellent candidate for use as a low-noise rf amplifier. Coupling of input signals of frequencies larger than 200 MHz, however, has been limited by the parasitic capacitance between the input coil and SQUID body. We present experimental observations of a do SQUID-based rf amplifier which circumvents this problem by incorporating the input coil as a microstrip resonator. The microstrip input configuration uses the capacitance and inductance of the input coil to form a resonant cavity capable of operating up to several GHz. The input signal is applied between the SQUID body and one end of the input coil, while the other end of the coil is left open. We present data from microstrip SQUID amplifiers with gains of up to 22 dB at 900 MHz. In order to understand the gain and input impedance of the microstrip SQUID in greater detail, we made and studied a 1:190 scale analog patterned on a double-sided printed circuit board consisting of copper deposited on a kapton sheet. The measured input impedance of the analog SQUID is successfully modeled by describing the microstrip input as a low-loss transmission line. When operated with the slit in the copper washer ground plane shorted, the input coil behaves exactly like a linear resonator with the resonant frequency given by f = 1/2?(L 0C0)1/2, where L0 and C0 are the inductance and capacitance per unit length and ? is the coil length. With the slit in the washer left open, the inductance of the input coil is significantly altered in a manner partially consistent with the Ketchen-Jaycox model in which the reflected inductance of the input coil is Li = n2L, where L is the inductance of the washer loop and n is the number of turns in the coil. We present input impedance measurements on microstrip SQUIDs cooled to 4.2 K. The low-loss transmission line model fits the real and imaginary parts of the microstrip input impedance very accurately. We map the low-loss transmission line model into an equivalent parallel RLC circuit in which a resistance R, inductance L, and capacitance C are calculated from the characteristic impedance and attenuation factor determined from the fits to the input impedance data. Using this equivalent RLC circuit, we model the microstrip SQUID and input network with a lumped circuit model which accurately predicts the observed gain of the amplifier. We find that gain is maximized when the input circuit is critically matched, with the imaginary part of the input impedance summing to zero and the real part equal to the 50O resistance of the coaxial input line. Thus, the full signal power is transmitted into the microstrip resonator and is dissipated in the equivalent resistance R.

Therrien, Roy

244

Self-amplifying mRNA vaccines.  

PubMed

This chapter provides a brief introduction to nucleic acid-based vaccines and recent research in developing self-amplifying mRNA vaccines. These vaccines promise the flexibility of plasmid DNA vaccines with enhanced immunogenicity and safety. The key to realizing the full potential of these vaccines is efficient delivery of nucleic acid to the cytoplasm of a cell, where it can amplify and express the encoded antigenic protein. The hydrophilicity and strong net negative charge of RNA impedes cellular uptake. To overcome this limitation, electrostatic complexation with cationic lipids or polymers and physical delivery using electroporation or ballistic particles to improve cellular uptake has been evaluated. This chapter highlights the rapid progress made in using nonviral delivery systems for RNA-based vaccines. Initial preclinical testing of self-amplifying mRNA vaccines has shown nonviral delivery to be capable of producing potent and robust innate and adaptive immune responses in small animals and nonhuman primates. Historically, the prospect of developing mRNA vaccines was uncertain due to concerns of mRNA instability and the feasibility of large-scale manufacturing. Today, these issues are no longer perceived as barriers in the widespread implementation of the technology. Currently, nonamplifying mRNA vaccines are under investigation in human clinical trials and can be produced at a sufficient quantity and quality to meet regulatory requirements. If the encouraging preclinical data with self-amplifying mRNA vaccines are matched by equivalently positive immunogenicity, potency, and tolerability in human trials, this platform could establish nucleic acid vaccines as a versatile new tool for human immunization. PMID:25620012

Brito, Luis A; Kommareddy, Sushma; Maione, Domenico; Uematsu, Yasushi; Giovani, Cinzia; Berlanda Scorza, Francesco; Otten, Gillis R; Yu, Dong; Mandl, Christian W; Mason, Peter W; Dormitzer, Philip R; Ulmer, Jeffrey B; Geall, Andrew J

2015-01-01

245

Acid Generation Mechanism for Extreme Ultraviolet Resists Containing Pinanediol Monosulfonate Acid Amplifiers: A Pulse Radiolysis Study  

NASA Astrophysics Data System (ADS)

Very highly sensitive resists are required for extreme ultraviolet (EUV, 13.5 nm) lithography, which is regarded as the most promising next-generation lithography. Chemically amplified resists have been proposed to increase acid yield and sensitivity through the use of an acid amplifier. There are two steps for acid generation in chemically amplified resists: initial acid generation and acid amplification. The first systematic research on the acid generation mechanisms of chemically amplified resists showing the involvement of acid amplifiers has been performed by both time-resolved pulse radiolysis and spectrophotometric titration methods. The role of acid amplifiers in acid generation processes, initiated by exposure, has been clarified using toluene and trifluoromethylbenzene derivatives of pinanediol monosulfonate.

Enomoto, Kazuyuki; Arimitsu, Koji; Yoshizawa, Atsutaro; Joshi, Ravi; Yamamoto, Hiroki; Oshima, Akihiro; Kozawa, Takahiro; Tagawa, Seiichi

2012-04-01

246

Suicide Risk: Amplifiers and Attenuators.  

ERIC Educational Resources Information Center

Attempts to integrate findings on correlates of suicide and violent risk in terms of a theory called a two-stage model of countervailing forces, which assumes that the strength of aggressive impulses is modified by amplifiers and attenuators. The vectorial interaction of amplifiers and attenuators creates an unstable equilibrium making prediction…

Plutchik, Robert; Van Praag, Herman M.

1994-01-01

247

2014 Amplifier -1 FREQUENCY RESPONSE OF  

E-print Network

2014 Amplifier - 1 FREQUENCY RESPONSE OF AN AUDIO AMPLIFIER The objectives of this experiment are amplifier Ā· To thoroughly bore you APPARATUS: Audio Amplifier (Circuit Chip), Computer with FFTScope software, Speaker, Power supply, Interconnecting Cables good high fidelity amplifier will have frequency

Glashausser, Charles

248

A position sensitive microchannel photomultiplier for ultraviolet space astronomy  

NASA Technical Reports Server (NTRS)

The 25-mm microchannel-plate, position-sensitive UV astronomy photomultiplier tube presented is intended for the EOM-1 Spacelab Mission's FAUST payload and conducts wide-field imaging surveys in the VUV over the 1400-1800-A range. The sealed detector encompasses a CsI photocathode deposited on the inner surface of a MgF2 window, a stack of microchannel plates, and a wedge-and-strip two-dimensional position-sensing anode. Since the wedge-and-strip principle requires only three anode signals, flight electronics can be reduced to three charge amplifiers and three analog-to-digital converters.

Lampton, M.; Siegmund, O. H. W.; Bixler, J.; Bowyer, S.

1986-01-01

249

Fluid pressure amplifier and system  

NASA Technical Reports Server (NTRS)

A flueric beam-deflection amplifier and a method of controlling the same are described. Either a single or a series of cascaded fluid amplifier units are provided and each one of which may include the usual power nozzle, control nozzles, outlet passages and vent passages. All vent passages of each fluid amplifier unit lead to an enclosed vent outlet chamber which is connected to the ambient environment or to a return manifold through a variably restricted passage. To control the fluid amplifier unit, power and control stream pressures are first established, after which the restricted passage is reduced to regulate the input bias, the gain and the input impedance of the fluid amplifier unit.

Garner, H. D.; Hellbaum, R. F. (inventors)

1973-01-01

250

Outphase power amplifiers in OFDM systems  

E-print Network

A trade-off between linearity and efficiency exists in conventional power amplifiers. The outphase amplifying concept overcomes this trade-off by enabling the use of high efficiency, non-linear power amplifiers for linear ...

Ph?m, Anh D., 1974-

2006-01-01

251

Dispersive liquid-liquid microextraction prior to field-amplified sample injection for the sensitive analysis of 3,4-methylenedioxymethamphetamine, phencyclidine and lysergic acid diethylamide by capillary electrophoresis in human urine.  

PubMed

A novel capillary zone electrophoresis (CZE) with ultraviolet detection method has been developed and validated for the analysis of 3,4-methylenedioxymethamphetamine (MDMA), lysergic acid diethylamide (LSD) and phencyclidine (PCP) in human urine. The separation of these three analytes has been achieved in less than 8 min in a 72-cm effective length capillary with 50-?m internal diameter. 100 mM NaH(2)PO(4)/Na(2)HPO(4), pH 6.0 has been employed as running buffer, and the separation has been carried out at temperature and voltage of 20°C, and 25kV, respectively. The three drugs have been detected at 205 nm. Field amplified sample injection (FASI) has been employed for on-line sample preconcentration. FASI basically consists in a mismatch between the electric conductivity of the sample and that of the running buffer and it is achieved by electrokinetically injecting the sample diluted in a solvent of lower conductivity than that of the carrier electrolyte. Ultrapure water resulted to be the better sample solvent to reach the greatest enhancement factor. Injection voltage and time have been optimized to 5 kV and 20s, respectively. The irreproducibility associated to electrokinetic injection has been correcting by using tetracaine as internal standard. Dispersive liquid-liquid microextraction (DLLME) has been employed as sample treatment using experimental design and response surface methodology for the optimization of critical variables. Linear responses were found for MDMA, PCP and LSD in presence of urine matrix between 10.0 and 100 ng/mL approximately, and LODs of 1.00, 4.50, and 4.40 ng/mL were calculated for MDMA, PCP and LSD, respectively. The method has been successfully applied to the analysis of the three drugs of interest in human urine with satisfactory recovery percentages. PMID:23141624

Airado-Rodrķguez, Diego; Cruces-Blanco, Carmen; Garcķa-Campańa, Ana M

2012-12-01

252

RF Single Electron Transistor Readout Amplifiers for Superconducting Astronomical Detectors for X-Ray to Sub-mm Wavelengths  

NASA Technical Reports Server (NTRS)

We report progress on using a new type of amplifier, the Radio-Frequency Single-Electron Transistor (RF-SET), to develop multi-channel sensor readout systems for fast and sensitive readout of high impedance cryogenic photodetectors such as Superconducting Tunnel Junctions and Single Quasiparticle Photon Counters. Although cryogenic, these detectors are desirable because of capabilities not other-wise attainable. However, high impedances and low output levels make low-noise, high-speed readouts challenging, and large format arrays would be facilitated by compact, low-power, on-chip integrated amplifiers. Well-suited for this application are RF-SETs, very high performance electrometers which use an rf readout technique to provide 100 MHz bandwidth. Small size, low power, and cryogenic operation allow direct integration with detectors, and using multiple rf carrier frequencies permits simultaneous readout of 20-50 amplifiers with a common electrical connection. We describe both the first 2-channel demonstration of this wavelength division multiplexing technique for RF-SETs, and Charge-Locked-Loop operation with 100 kHz of closed-loop bandwidth.

Stevenson, Thomas; Aassime, Abdelhanin; Delsing, Per; Frunzio, Luigi; Li, Li-Qun; Prober, Daniel; Schoelkopf, Robert; Segall, Ken; Wilson, Chris; Stahle, Carl

2000-01-01

253

Active hair-bundle movements can amplify a hair cell's response to oscillatory mechanical stimuli  

E-print Network

Active hair-bundle movements can amplify a hair cell's response to oscillatory mechanical stimuli, 1999 To enhance their mechanical sensitivity and frequency selectivity, hair cells amplify the mechanical stimuli to which they respond. Although cell-body contractions of outer hair cells are thought

Hudspeth, A. James

254

A Direct-Current Amplifier Employing Negative Feedback for Measuring Stellar Photoelectric Currents  

Microsoft Academic Search

In this paper a direct-current amplifier is described which employs negative feedback for the measurement of small stellar photoelectric currents. A General Electric type FP-54 electrometer tube is used in the input stage to give maximum sensitivity. The output voltage is fed back negatively into the input stage and the amplifier locks in a condition of equilibrium. In this condition

Q. S. Heidelberg; W. A. Rense

1940-01-01

255

Does the Sun work as a nuclear fusion amplifier of  

E-print Network

Does the Sun work as a nuclear fusion amplifier of planetary tidal forcing? Nicola Scafetta ACRIM oscillates because of planetary motion The Sun is likely very sensitive to these oscillations March 1977); We reconstruct here Sun-centred planetary conjunctions and tidal potentials for the AD 1645

Scafetta, Nicola

256

Piezoelectric rubber films for highly sensitive impact measurement  

NASA Astrophysics Data System (ADS)

We have successfully demonstrated the microfabrication of piezoelectric rubber films and their application in impact measurement. To realize the desired piezoelectricity and stretchability, cellular polydimethylsiloxane (PDMS) structures with micrometer-sized voids are internally implanted with bipolar charges, which function as dipoles and respond promptly to electromechanical stimuli. In the prototype demonstration, 300 µm thick cellular PDMS films are fabricated and internally coated with a thin polytetrafluoroethylene (PTFE) layer to secure the implanted charges. Meanwhile, the top and bottom surfaces of the cellular PDMS films are deposited with stretchable gold electrodes. An electric field up to 35 MV m-1 is applied across the gold electrodes to ionize the air in the voids and to implant charges on the inner surfaces. The resulting composite structures behave like rubber (with an elastic modulus of about 300 kPa) and show strong piezoelectricity (with a piezoelectric coefficient d33 higher than 1000 pC N-1). While integrated with a wide bandwidth and large dynamic-range charge amplifier, highly sensitive impact measurement (with a stress sensitivity of about 10 mV Pa-1) is demonstrated. As such, the demonstrated piezoelectric rubber films could potentially serve as a sensitive electromechanical material for low-frequency stimuli, and fulfill the needs of a variety of physiological monitoring and wearable electronics applications.

Wang, Jhih-Jhe; Tsai, Jui-Wei; Su, Yu-Chuan

2013-07-01

257

Recent advances in chemically amplified resist materials  

SciTech Connect

The design of resists based on the principle of chemical amplification has provided imaging materials with remarkable sensitivity. These materials all function on the basis of photo-generation of a latent image of catalyst. In a subsequent step that is usually thermally activated, the catalyst acts on some part of the formulation to modify the solubility of the film. In most cases reported to date, the systems depend on acid that is generated by the irradiation of neutral compounds which produce acidic radiolysis products. Acid catalysis of side chain cleavage, cross-linking, and hydrolysis are but a few of the reactions that have been exploited in the design of acid catalyzed, chemically amplified resists. This paper now reports the authors` work on the use of photo-generated base in the design of resists that derive high sensitivity from base catalyzed chemical transformations. A variety of base catalyzed reactions have been auditioned for this application.

Willson, C.G.; MacDonald, S.A.; Niesert, C.P. [IBM Almaden Research Center, San Jose, CA (United States); Frechet, J.M.J.; Leung, M.K.; Ackerman, A. [Cornell Univ., Ithaca, NY (United States)

1993-12-31

258

Amplifier arrays for CMB polarization  

NASA Technical Reports Server (NTRS)

Cryogenic low noise amplifier technology has been successfully used in the study of the cosmic microwave background (CMB). MMIC (Monolithic Millimeter wave Integrated Circuit) technology makes the mass production of coherent detection receivers feasible.

Gaier, Todd; Lawrence, Charles R.; Seiffert, Michael D.; Wells, Mary M.; Kangaslahti, Pekka; Dawson, Douglas

2003-01-01

259

Transistor oscillator and amplifier grids  

Microsoft Academic Search

Although quasi-optical techniques are applicable to a large variety of solid-state devices, special attention is given to transistors, which are attractive because they can be used as either amplifiers or oscillators. Experimental results for MESFET bar-grid and planar grid oscillators are presented. A MESFET grid amplifier that receives only vertically polarized waves at the input and radiates horizontally polarized waves

ROBERT M. WEIKLE; MOONIL KIM; JONATHAN B. HACKER; MICHAEL P. DE LISIO; ZOYA B. POPOVIC; DAVID B. RUTLEDGE

1992-01-01

260

Statistical Mechanics of Amplifying Apparatus  

E-print Network

We implement Feynman's suggestion that the only missing notion needed for the puzzle of Quantum Measurement is the statistical mechanics of amplifying apparatus. We define a thermodynamic limit of quantum amplifiers which is a classically describable system in the sense of Bohr, and define macroscopic pointer variables for the limit system. Then we derive the probabilities of Quantum Measurement from the deterministic Schroedinger equation by the usual techniques of Classical Statistical Mechanics.

Joseph Johnson

2005-02-08

261

Single Ion Quantum Lock-In Amplifier  

E-print Network

We report on the implementation of a quantum analog to the classical lock-in amplifier. All the lock-in operations: modulation, detection and mixing, are performed via the application of non-commuting quantum operators on the electronic spin state of a single trapped Sr+ ion. We significantly increase its sensitivity to external fields while extending phase coherence by three orders of magnitude, to more than one second. With this technique we measure magnetic fields with sensitivity of 25 pT/sqrt(Hz) and light shifts with an uncertainty below 140 mHz after 1320 seconds of averaging. These sensitivities are limited by quantum projection noise and, to our knowledge, are more than two orders of magnitude better than with other single-spin probe technologies. In fact, our reported sensitivity is sufficient for the measurement of parity non-conservation, as well as the detection of the magnetic field of a single electronic-spin one micrometer from an ion-detector with nanometer resolution. As a first application we perform light shift spectroscopy of a narrow optical quadruple transition. Finally, we emphasize that the quantum lock-in technique is generic and can potentially enhance the sensitivity of any quantum sensor.

Shlomi Kotler; Nitzan Akerman; Yinnon Glickman; Anna Keselman; Roee Ozeri

2011-01-25

262

Variable gain, zero offset, dc coupled video amplifier for microwave detector diodes  

NASA Astrophysics Data System (ADS)

A variable gain, zero offset, dc coupled video amplifier has been developed which uses a recently introduced ±5 V operational amplifier with 1.6 GHz gain-bandwidth product. The amplifier is inexpensive and it is particularly suited for amplifying the outputs of microwave diode detectors and driving 50 ? loads. The large input bias currents of wideband operational amplifiers increase the sensitivity of positive polarity diode detectors, but they decrease the sensitivity when a negative polarity diode detector is used at the amplifier input. To eliminate this effect, matched N-channel junction field-effect transistors (JFETs) are used to buffer the operational amplifier inputs, which reduces the input bias current to ˜1 pA. An added benefit of the JFETs is that the amplifier offset voltage is unaffected by changes in gain or source impedance. Once the offset is zeroed out, it remains zero for all gains and for any combination of diode detectors connected at the input. The maximum attainable gain-bandwidth product is somewhat lower with the JFETs (typically 400 MHz), but the amplifier operates reliably for gains up to 40-50 dB.

Mathew, J.

1995-09-01

263

Rain Drop Charge Sensor  

NASA Astrophysics Data System (ADS)

begin{center} Large Large Rain Drop Charge Sensor Sreekanth T S*, Suby Symon*, G. Mohan Kumar (1) , S. Murali Das (2) *Atmospheric Sciences Division, Centre for Earth Science Studies, Thiruvananthapuram 695011 (1) D-330, Swathi Nagar, West Fort, Thiruvananthapuram 695023 (2) Kavyam, Manacaud, Thiruvananthapuram 695009 begin{center} ABSTRACT To study the inter-relations with precipitation electricity and precipitation microphysical parameters a rain drop charge sensor was designed and developed at CESS Electronics & Instrumentation Laboratory. Simultaneous measurement of electric charge and fall speed of rain drops could be done using this charge sensor. A cylindrical metal tube (sensor tube) of 30 cm length is placed inside another thick metal cover opened at top and bottom for electromagnetic shielding. Mouth of the sensor tube is exposed and bottom part is covered with metal net in the shielding cover. The instrument is designed in such a way that rain drops can pass only through unhindered inside the sensor tube. When electrically charged rain drops pass through the sensor tube, it is charged to the same magnitude of drop charge but with opposite polarity. The sensor tube is electrically connected the inverted input of a current to voltage converter operational amplifier using op-amp AD549. Since the sensor is electrically connected to the virtual ground of the op-amp, the charge flows to the ground and the generated current is converted to amplified voltage. This output voltage is recorded using a high frequency (1kHz) voltage recorder. From the recorded pulse, charge magnitude, polarity and fall speed of rain drop are calculated. From the fall speed drop diameter also can be calculated. The prototype is now under test running at CESS campus. As the magnitude of charge in rain drops is an indication of accumulated charge in clouds in lightning, this instrument has potential application in the field of risk and disaster management. By knowing the charge magnitude of initial drops from a precipitation event, gross cloud charge can be estimated and necessary precautions can be taken during convective cloud events. Being a site of high lightning incidence in tropics, Kerala state is affected in India and calls for much attention in lightning hazards mitigation. Installing this charge sensor and atmospheric electric field mill, an attempt to a better warning system can be attempted.

S, Sreekanth T.

264

Functional importance of ?38 and ?39 in distinct tRNAs, amplified for tRNAGln(UUG) by unexpected temperature sensitivity of the s2U modification in yeast.  

PubMed

The numerous modifications of tRNA play central roles in controlling tRNA structure and translation. Modifications in and around the anticodon loop often have critical roles in decoding mRNA and in maintaining its reading frame. Residues U38 and U39 in the anticodon stem-loop are frequently modified to pseudouridine (?) by members of the widely conserved TruA/Pus3 family of pseudouridylases. We investigate here the cause of the temperature sensitivity of pus3? mutants of the yeast Saccharomyces cerevisiae and find that, although ?38 or ?39 is found on at least 19 characterized cytoplasmic tRNA species, the temperature sensitivity is primarily due to poor function of tRNA(Gln(UUG)), which normally has ?38. Further investigation reveals that at elevated temperatures there are substantially reduced levels of the s(2)U moiety of mcm(5)s(2)U34 of tRNA(Gln(UUG)) and the other two cytoplasmic species with mcm(5)s(2)U34, that the reduced s(2)U levels occur in the parent strain BY4741 and in the widely used strain W303, and that reduced levels of the s(2)U moiety are detectable in BY4741 at temperatures as low as 33°C. Additional examination of the role of ?38,39 provides evidence that ?38 is important for function of tRNA(Gln(UUG)) at permissive temperature, and indicates that ?39 is important for the function of tRNA(Trp(CCA)) in trm10? pus3? mutants and of tRNA(Leu(CAA)) as a UAG nonsense suppressor. These results provide evidence for important roles of both ?38 and ?39 in specific tRNAs, and establish that modification of the wobble position is subject to change under relatively mild growth conditions. PMID:25505024

Han, Lu; Kon, Yoshiko; Phizicky, Eric M

2015-02-01

265

Handout 3 for EE-203 Differential Amplifiers  

E-print Network

Handout 3 for EE-203 Differential Amplifiers Sheikh Sharif Iqbal (Ref: Text book and KFUPM Online and applications associated with differential amplifiers. - Differential amplifier pair is a fundamental subcircuit used in the input stage of every operational amplifiers and many other linear integrated circuits

Iqbal, Sheikh Sharif

266

Four-Channel Differential AC Amplifier  

E-print Network

Four-Channel Differential AC Amplifier #12;INSTRUCTION MANUAL FOR HIGH-GAIN DIFFERENTIAL AMPLIFIER .......................................................................................................13 Each Differential AC Amplifier is delivered complete with: Four 3' Cables Rack Mount Hardware://www.a-msystems.com General Description Instrument Features The Four-Channel Differential AC Amplifier Model 1700 is designed

Kleinfeld, David

267

A solid state amplifier for the flame ionization detector used in gas chromatography  

Microsoft Academic Search

Describes a solid state current amplifier with which a flame ionization detector can be used at all practicable sensitivity levels. The use of metal-oxide-silicon transistors in a conventional circuit gives a degree of stability significantly better than that achieved with thermionic electrometer valves. The amplifier has a sensitivity of 100 mV pA-1 and a noise output equivalent to 2*10-15A rms

D. F. Meigh; E. H. Oetzmann

1971-01-01

268

A MultiStage Solid State Amplifier  

Microsoft Academic Search

A solid state X-band amplifier consisting of five cascaded stages is described. The amplifier is of hybrid type, where combination of high power silicon IMPATT amplifier modules with a Gunn diode pre-amplifier stage provides an output power of greater than 13. Owatts. The gain of the amplifier is 26-dB, with an instantaneous bandwidth of 100MHz. Descriptions of single diode and

Amarjit S. Bains

1974-01-01

269

MAPK Cascades as Feedback Amplifiers  

E-print Network

Interconvertible enzyme cascades, exemplified by the mitogen activated protein kinase (MAPK) cascade, are a frequent mechanism in signal transduction pathways. There has been much speculation as to the role of these pathways, and how their structure is related to their function. A common conclusion is that the cascades serve to amplify biochemical signals so that a single bound ligand molecule might produce a multitude of second messengers. Some recent work has focused on a particular feature present in some MAPK pathways -- a negative feedback loop which spans the length of the cascade. This is a feature that is shared by a man-made engineering device, the feedback amplifier. We propose a novel interpretation: that by wrapping a feedback loop around an amplifier, these cascades may be acting as biochemical feedback amplifiers which imparts i) increased robustness with respect to internal perturbations; ii) a linear graded response over an extended operating range; iii) insulation from external perturbation, resulting in functional modularization. We also report on the growing list of experimental evidence which supports a graded response of MAPK with respect to Epidermal Growth Factor. This evidence supports our hypothesis that in these circumstances MAPK cascade, may be acting as a feedback amplifier.

Herbert M Sauro; Brian Ingalls

2007-10-26

270

Reflex ring laser amplifier system  

DOEpatents

The invention is a method and apparatus for providing a reflex ring laser system for amplifying an input laser pulse. The invention is particularly useful in laser fusion experiments where efficient production of high-energy and high power laser pulses is required. The invention comprises a large aperture laser amplifier in an unstable ring resonator which includes a combination spatial filter and beam expander having a magnification greater than unity. An input pulse is injected into the resonator, e.g., through an aperture in an input mirror. The injected pulse passes through the amplifier and spatial filter/expander components on each pass around the ring. The unstable resonator is designed to permit only a predetermined number of passes before the amplified pulse exits the resonator. On the first pass through the amplifier, the beam fills only a small central region of the gain medium. On each successive pass, the beam has been expanded to fill the next concentric non-overlapping region of the gain medium.

Summers, M.A.

1983-08-31

271

Broadband Characterization of a 100 to 180 GHz Amplifier  

NASA Technical Reports Server (NTRS)

Atmospheric science and weather forecasting require measurements of the temperature and humidity vs. altitude. These sounding measurements are obtained at frequencies close to the resonance frequencies of oxygen (118 GHz) and water (183 GHz) molecules. We have characterized a broadband amplifier that will increase the sensitivity of sounding and other instruments at these frequencies. This study demonstrated for the first t1me continuous low noise amplification from 100 to 180 GHz. The measured InP monolithic millimeter-wave Integrated circuit (MMIC) amplifier had more than 18 dB of gain from 100 to 180 GHz and 15 dB of gain up to 220 GHz. This is the widest bandwidth low noise amplifier result at these frequencies to date. The circuit was fabricated in Northrop Grumman Corporation 35 nm InP high electron mobility transistor (HEMT).

Kangaslahti, Pekka; Deal, W. R.; Mei, X. B.; Lai, R.

2007-01-01

272

How much quantum noise of amplifiers is detrimental to entanglement  

E-print Network

We analyze the effect of the quantum noise of an amplifier on the entanglement properties of an input state. We consider both phase insensitive and phase sensitive amplification and specialize to Gaussian states for which entanglement measures are well developed. In the case of phase insensitive amplification in which both the modes are symmetrically amplified, we find that the entanglement in the output state vanishes if the intensity gain exceeds a limiting value $2/(1+\\exp[-E_N])$ where $E_N$ is the logarithmic negativity of the input state which quantifies the initial entanglement between the two modes. The entanglement between the two modes at the output is found to be more robust if only one mode is amplified.

G. S. Agarwal; S. Chaturvedi

2009-11-17

273

The PreAmplifier ShAper for the ALICE TPC detector  

NASA Astrophysics Data System (ADS)

In this paper the PreAmplifier ShAper (PASA) for the Time Projection Chamber (TPC) of the ALICE experiment at LHC is presented. The ALICE TPC PASA is an ASIC that integrates 16 identical channels, each consisting of Charge Sensitive Amplifiers (CSA) followed by a Pole-Zero network, self-adaptive bias network, two second-order bridged-T filters, two non-inverting level shifters and a start-up circuit. The circuit is optimized for a detector capacitance of 18-25 pF. For an input capacitance of 25 pF, the PASA features a conversion gain of 12.74 mV/fC, a peaking time of 160 ns, a FWHM of 190 ns, a power consumption of 11.65 mW/ch and an equivalent noise charge of 244e+17e/pF. The circuit recovers smoothly to the baseline in about 600 ns. An integral non-linearity of 0.19% with an output swing of about 2.1 V is also achieved. The total area of the chip is 18 mm2 and is implemented in AMS's C35B3C1 0.35 ?m CMOS technology. Detailed characterization tests were performed on about 48 000 PASA circuits before mounting them on the ALICE TPC front-end cards. After more than two years of operation of the ALICE TPC with p-p and Pb-Pb collisions, the PASA has demonstrated to fulfill all requirements.

Soltveit, H. K.; Stachel, J.; Braun-Munzinger, P.; Musa, L.; Gustafsson, H. A.; Bonnes, U.; Oeschler, H.; Osterman, L.; Lang, S.; ALICE TPC Collaboration

2012-06-01

274

Noncontact charge measurement  

NASA Technical Reports Server (NTRS)

A method for noncontact charge measurements is presented, which uses a system based on the reciprocal motion principle of a grounded conductor near a point charge. The system exhibits extremely good linearity with respect to the input electric field and has a resolution of greater than 10 V/m. The high sensitivity of the apparatus makes the system feasible for use at a safe distance in various applications for monitoring static charge.

Lin, Kuan-Chan; Wang, Taylor G.

1992-01-01

275

Integrated amplifier-accelerator system  

NASA Astrophysics Data System (ADS)

A theoretical investigation of the interaction of electrons with the electromagnetic wave in a microwave amplifier indicates that about 50% of the electrons are in fact accelerated in the amplification process. We analyze a system which consists of an amplifier immediately followed by an accelerator. Although we loose part of the electromagnetic power due to the impedance mismatch, the electrons remain bunched and trapped when entering the acceleration section so that the acceleration process is reasonably efficient. The electrons which lost energy in the amplifier section, practically do not participate in the interaction process, since their velocity mismatch is too large. With 1 kA, 0.85 MV electrons and Ez equals 0.6 MV/m at the input, 40.6 cm of amplification and 43.4 cm of acceleration, calculations show that at the output 6% of the electrons have energies between 8 and 16 MV.

Schaechter, Levi; Nation, John A.

1992-04-01

276

Integrating and amplifying signal from riboswitch biosensors.  

PubMed

Biosensors offer a built-in energy supply and inherent sensing machinery that when exploited correctly may surpass traditional sensors. However, biosensor systems have been hindered by a narrow range of ligand detection capabilities, a relatively low signal output, and their inability to integrate multiple signals. Integration of signals could increase the specificity of the sensor and enable detection of a combination of ligands that may indicate environmental or developmental processes when detected together. Amplifying biosensor signal output will increase detector sensitivity and detection range. Riboswitches offer the potential to widen the diversity of ligands that may be detected, and advances in synthetic biology are illuminating myriad possibilities in signal processing using an orthogonal parts-based engineering approach. In this chapter, we describe the design, building, and testing of a riboswitch-based Boolean logic AND gate in bacteria, where an output requires the activation of two riboswitches, and the biological circuitry required to amplify the output of the AND gate using natural extracellular bacterial communication signals to "wire" cells together. PMID:25605381

Goodson, Michael S; Harbaugh, Svetlana V; Chushak, Yaroslav G; Kelley-Loughnane, Nancy

2015-01-01

277

Optical amplifiers for coherent lidar  

NASA Technical Reports Server (NTRS)

We examine application of optical amplification to coherent lidar for the case of a weak return signal (a number of quanta of the return optical field close to unity). We consider the option that has been explored to date, namely, incorporation of an optical amplifier operated in a linear manner located after reception of the signal and immediately prior to heterodyning and photodetection. We also consider alternative strategies where the coherent interaction, the nonlinear processes, and the amplification are not necessarily constrained to occur in the manner investigated to date. We include the complications that occur because of mechanisms that occur at the level of a few, or one, quantum excitation. Two factors combine in the work to date that limit the value of the approach. These are: (1) the weak signal tends to require operation of the amplifier in the linear regime where the important advantages of nonlinear optical processing are not accessed, (2) the linear optical amplifier has a -3dB noise figure (SN(out)/SN(in)) that necessarily degrades the signal. Some improvement is gained because the gain provided by the optical amplifier can be used to overcome losses in the heterodyned process and photodetection. The result, however, is that introduction of an optical amplifier in a well optimized coherent lidar system results in, at best, a modest improvement in signal to noise. Some improvement may also be realized on incorporating more optical components in a coherent lidar system for purely practical reasons. For example, more compact, lighter weight, components, more robust alignment, or more rapid processing may be gained. We further find that there remain a number of potentially valuable, but unexplored options offered both by the rapidly expanding base of optical technology and the recent investigation of novel nonlinear coherent interference phenomena occurring at the single quantum excitation level. Key findings are: (1) insertion of linear optical amplifiers in well optimized conventional lidar systems offers modest improvements, at best, (2) the practical advantages of optical amplifiers, especially fiber amplifiers, such as ease of alignment, compactness, efficiency, lightweight, etc., warrant further investigation for coherent lidar, (3) the possibility of more fully optical lidar systems should be explored, (4) advantages gained by use of coherent interference of optical fields at the level of one, or a few, signal quanta should be explored, (5) amplification without inversion, population trapping, and use of electromagnetic induced transparency warrant investigation in connection with coherent lidar, (6) these new findings are probably more applicable to earth related NASA work, although applications to deep space should not be excluded, and (7) our own work in the Ultrafast Laboratory at UAH along some of the above lines of investigation, may be useful.

Fork, Richard

1996-01-01

278

Reactanceless synthesized impedance bandpass amplifier  

NASA Technical Reports Server (NTRS)

An active R bandpass filter network is formed by four operational amplifier stages interconnected by discrete resistances. One pair of stages synthesize an equivalent input impedance of an inductance (L sub eq) in parallel with a discrete resistance (R sub o) while the second pair of stages synthesizes an equivalent input impedance of a capacitance (C sub eq) serially coupled to another discrete resistance (R sub i) coupled in parallel with the first two stages. The equivalent input impedances aggregately define a tuned resonant bandpass filter in the roll-off regions of the operational amplifiers.

Kleinberg, L. L. (inventor)

1985-01-01

279

Random Number Generation Using Amplified Spontaneous Emission in a Fiber Amplifier  

E-print Network

Random Number Generation Using Amplified Spontaneous Emission in a Fiber Amplifier Julia C. Salevan Ā· Photon counting Ā· Amplified spontaneous emission #12;System Er:Yb EDFA Bandpass Filter (FBG) ( 0 = 1552

Anlage, Steven

280

12.0 Power Amplifiers 1 of 37 12.0 Power Amplifiers 2 of 37  

E-print Network

12.0 Power Amplifiers 1 of 37 #12;12.0 Power Amplifiers 2 of 37 #12;12.0 Power Amplifiers 3 of 37 #12;12.0 Power Amplifiers 4 of 37 #12;12.0 Power Amplifiers 5 of 37 Class A Power Calculations Pi = (Icpp)2 *Rc /8 and since, Vcpp = Icpp *Rc then, Po(ac) = Vcpp* Icpp /8 #12;12.0 Power Amplifiers 6 of 37

Allen, Gale

281

Isothermal amplified detection of DNA and RNA.  

PubMed

This review highlights various methods that can be used for a sensitive detection of nucleic acids without using thermal cycling procedures, as is done in PCR or LCR. Topics included are nucleic acid sequence-based amplification (NASBA), strand displacement amplification (SDA), loop-mediated amplification (LAMP), Invader assay, rolling circle amplification (RCA), signal mediated amplification of RNA technology (SMART), helicase-dependent amplification (HDA), recombinase polymerase amplification (RPA), nicking endonuclease signal amplification (NESA) and nicking endonuclease assisted nanoparticle activation (NENNA), exonuclease-aided target recycling, Junction or Y-probes, split DNAZyme and deoxyribozyme amplification strategies, template-directed chemical reactions that lead to amplified signals, non-covalent DNA catalytic reactions, hybridization chain reactions (HCR) and detection via the self-assembly of DNA probes to give supramolecular structures. The majority of these isothermal amplification methods can detect DNA or RNA in complex biological matrices and have great potential for use at point-of-care. PMID:24643211

Yan, Lei; Zhou, Jie; Zheng, Yue; Gamson, Adam S; Roembke, Benjamin T; Nakayama, Shizuka; Sintim, Herman O

2014-05-01

282

The School as an Amplifier.  

ERIC Educational Resources Information Center

This paper attempts to show that adaptation of mathematics to the input-output model of the school can provide powerful assistance in the measurement and analysis of school quality and its determinants. The mathematical relationship described here relates an educational model to the field of electronics. More specifically, the amplifier, a device…

Vincent, William S.

1966-01-01

283

Stroke amplifier for deformable mirrors  

PubMed Central

We demonstrate a simple optical configuration that amplifies the usable stroke of a deformable mirror. By arranging for the wavefront to traverse the deformable mirror more than once, we correct it more than once. The experimental implementation of the idea demonstrates a doubling of 2.0 and 2.04 by two different means. PMID:15495423

Webb, Robert H.; Albanese, Marc J.; Zhou, Yaopeng; Bifano, Thomas; Burns, Stephen A.

2010-01-01

284

HARMONIC AMPLIFIER FREE ELECTRON LASER  

Microsoft Academic Search

The harmonic optical klystron (HOK) in which the second undulator is resonant on the higher harmonic of the first undulator is analysed as a harmonic amplifier. The optical field evolution equation of the HOK is derived analytically for both CHG mode (Coherent Harmonic Generation, the quadratic gain regime) and HGHG mode (High Gain Harmonic Generation, the exponential gain regime), the

Jia Qika

285

Final amplifier for laser accelerators  

NASA Astrophysics Data System (ADS)

We demonstrate the existence of the severe losses due ASE and ability EDP technique to suppress it andparasitic lasing. The optimal conditions that can deliver up to kJ level energy with existing technology are presented. Keywords: Ultrahigh power lasers; Laser amplifiers.

Yanovsky, V. Chvykov V.; Kalinchenko, G.; Rousseau, P.; Maksimchuk, A.; Krushelnick, K.

2012-12-01

286

Influence of counter-anions during electrochemical deposition of ZnO on the charge transport dynamics in dye-sensitized solar cells.  

PubMed

Porous ZnO/EosinY films have been electrochemically deposited by oxygen reduction in the presence of a zinc salt from EosinY-containing aqueous solutions, with either chloride or perchlorate as the counter anion. EosinY was removed and the films were sensitised by D149. These electrodes were used for dye-sensitised solar cells (DSCs), and charge transport in the porous network was studied by intensity modulated current/voltage spectroscopy (IMVS/IMPS) and electrochemical impedance spectroscopy (EIS) under illumination. Doping of ZnO during the electrodeposition could be proven by changes in the charge transport in ZnO and could be shown to occur when chloride was used as the counter ion. By using perchlorate as the counter ion, on the other hand, a more reproducible occupation of trap levels was obtained at, however, slightly lower voltages in DSCs whose origin is discussed in detail. PMID:25474267

Richter, Christoph; Beu, Max; Schlettwein, Derck

2015-01-21

287

Characterizing the thermal sensitivity of a gasoline homogeneous charge compression ignition engine with measurements of instantaneous wall temperature and heat flux  

Microsoft Academic Search

An experimental study was performed to provide qualitative and quantitative insight into the thermal effects on a gasoline-fuelled homogeneous charge compression ignition (HCCI) engine combustion. The single-cylinder engine utilized exhaust gas rebreathing to obtain large amounts of hot residual gas needed to promote ignition. In-cylinder pressure, heat release analysis, and exhaust emission measurement were employed for combustion diagnostics. Fast response

J Chang; Z Filipi; D Assanis; T-W Kuo; P Najt; R Rask

2005-01-01

288

On the Noise Properties of Balanced Amplifiers  

NASA Astrophysics Data System (ADS)

The balanced amplifier is used in applications requiring a better input match than is possible with a single-ended amplifier. While the impedance matching property of the balanced amplifier is well known, its noise behavior appears not to be widely understood. It is shown that the outgoing noise waves at the input and output of a balanced amplifier are uncorrelated even though they originate in the same components. Hence, a sliding short-circuit at the input produces no variation in the output noise of the amplifier. The properties of a balanced amplifier are similar to those of an amplifier preceded by an isolator, although the noise wave emerging from inputs of the two circuits originates in different elements. The noise theory of the balanced amplifier applies also to balanced mixers based on quadrature hybrids.

Kerr, A. R.

289

New architecture for RF power amplifier linearization  

E-print Network

Power amplifier linearization has become an important part of the transmitter system as 3G and developing 4G communication standards require higher linearity than ever before. The thesis proposes two power amplifier ...

Boo, Hyun H

2009-01-01

290

Design of a Casimir-driven parametric amplifier  

NASA Astrophysics Data System (ADS)

In this paper, we discuss a design for a MEMS parametric amplifier modulated by the Casimir force. We present the theory for such a device and show that it allows for the implementation of a very sensitive voltage measuring technique, where the amplitude of a high quality factor resonator includes a tenth power dependency on an applied DC voltage. This approach opens up a new and powerful measuring modality, applicable to other measurement types.

Imboden, M.; Morrison, J.; Campbell, D. K.; Bishop, D. J.

2014-10-01

291

A multi-stage solid state amplifier  

Microsoft Academic Search

A solid state X-band amplifier consisting of five cascaded stages is described. The amplifier is of hybrid type, where combination of high power silicon IMPATT amplifier modules with a Gunn diode preamplifier stage provides an output power of greater than 13.0 W. The gain of the amplifier is 26 dB, with an instantaneous bandwidth of 100 MHz. Descriptions of single

A. S. Bains

1974-01-01

292

mm-wave solid state amplifiers  

Microsoft Academic Search

The development of mm-wave amplifiers using InP Gunn diodes is reviewed including a low-noise eight-stage amplifier for replacement of a Ka-band TWTA and a three-stage amplifier for the 42.5 to 44.5 range with an output power of 100 mW and 20 dB associated gain. A detailed description of a three-stage amplifier for the 54 to 58 GHz range is given

P. H. Wolfert; J. D. Crowley; F. B. Fank

1983-01-01

293

Operational Amplifier Circuits ECE 2100 Circuit Analysis  

E-print Network

1 Operational Amplifier Circuits ECE 2100 Circuit Analysis updated 11 May 2012 Pre voltage source Vin assuming that the operational amplifier is not saturated (thus there is negative of this amplifier circuit? 2. Use your SPICE engine to plot Vout as a function of Vin as Vin is varied from -2V to 2

Miller, Damon A.

294

Efficient Amplifiers and Bounded Degree Optimization  

E-print Network

Efficient Amplifiers and Bounded Degree Optimization Piotr Berman \\Lambda Marek Karpinski y Abstract This paper studies the existence of efficient (small size) amplifiers for provĀ­ ing explicit an explicit construction for such amplifiers. We use this construction to improve the currently best known

Eckmiller, Rolf

295

Modeling erbium-doped fiber amplifiers  

Microsoft Academic Search

Erbium-doped fiber amplifiers are modeled using the propagation and rate equations of a homogeneous two-level laser medium. Numerical methods are used to analyze the effects of optical modes and erbium confinement on amplifier performance, and to calculate both the gain and amplified spontaneous emission (ASE) spectra. Fibers with confined erbium doping are completely characterized from easily measured parameters: the ratio

C. Randy Giles; Emmanuel Desurvire

1991-01-01

296

Two stage double layer microstrip spatial amplifiers  

Microsoft Academic Search

Several two stage spatial amplifiers are presented. The amplifiers were constructed on double layer back to back microstrip circuits with a shared ground plane. The ground plane provides an effective isolation between the receiving antenna array and the transmitting antenna array. Furthermore, it serves as a heat sink in high-power amplifier design. The coupling between the two stages is accomplished

Toni Ivanov; Arnir Mortazawi

1995-01-01

297

Soliton transmission control with semiconductor amplifiers  

NASA Astrophysics Data System (ADS)

A signal propagating along a dispersive transmission line in which loss is compensated by semiconductor amplifiers suffers from strong memory effects induced by the amplifier saturation. Insertion of filters along a line of anomalous dispersion reduces the detrimental effects of the amplifier saturation.

Mecozzi, Antonio

1995-08-01

298

Solid state ku-band power amplifier  

NASA Technical Reports Server (NTRS)

The design, fabrication, and testing of two types of IMPATT diode reflection amplifiers and a transmission amplifier are given. The Ku-band IMPATT diode development is discussed. Circuitry and electrical performance of the final version of the Ku-band amplifier is described. Construction details and an outline and mounting drawing are presented.

Bowers, H. C.; Lockyear, W. H.

1972-01-01

299

Solid state, S-band, power amplifier  

NASA Technical Reports Server (NTRS)

The final design and specifications for a solid state, S-band, power amplifier is reported. Modifications from a previously proposed design were incorporated to improve efficiency and meet input overdrive and noise floor requirements. Reports on the system design, driver amplifier, power amplifier, and voltage and current limiter are included along with a discussion of the testing program.

Digrindakis, M.

1973-01-01

300

Series transistors isolate amplifier from flyback voltage  

NASA Technical Reports Server (NTRS)

Circuit enables high sawtooth currents to be passed through a deflection coil and isolate the coil driving amplifier from the flyback voltage. It incorporates a switch consisting of transistors in series with the driving amplifier and deflection coil. The switch disconnects the deflection coil from the amplifier during the retrace time.

Banks, W.

1967-01-01

301

AC instrumentation amplifier for bioimpedance measurements  

Microsoft Academic Search

The input impedance and common-mode rejection ratio requirements for an amplifier for bioimpedance measurements are analyzed, considering the capacitive components of the electrode-skin contact impedance. An AC-coupled instrumentation amplifier that fulfills those requirements, and provides both interference and noise reduction and a zero phase shift over a wide frequency band without using broadband operational amplifiers, is described.

R. Pallas-Areny; J. G. Webster

1993-01-01

302

Design of hysteresis circuits using differential amplifiers  

NASA Technical Reports Server (NTRS)

Design equations for hysteresis circuit are based on the following assumptions: amplifier input impedance is larger than source impedance; amplifier output impedance is less than load impedance; and amplifier switches state when differential input voltage is approximately zero. Circuits are designed to any given specifications.

Cooke, W. A.

1971-01-01

303

Valves Based on Amplified Piezoelectric Actuators  

Microsoft Academic Search

Amplified Piezo Actuators have been developed at CEDRAT TECHNOLOGIES for several years and found several applications in space. Their well-known advantages (rapid response and precise positioning) have been used in valve designs to obtain either rapid or fine proportional valves. A first gas valve is using a small amplified piezo actuator and is further driven with a switched amplifier to

R. Le Letty; N. Lhermet; G. Patient; F. Claeyssen; M. Lang

2004-01-01

304

Random Number Generation Using Amplified Spontaneous Emission in a Fiber Amplifier  

E-print Network

Random Number Generation Using Amplified Spontaneous Emission in a Fiber Amplifier Julia C. Salevan methods including photon counting and chaotic systems. Ā· We examine an optical system using the amplified spontaneous emission in a fiber amplifier as our random source. System Conclusions and Future Work Statistical

Anlage, Steven

305

An Amplified Sensitivity Arising from Covalent Modification in Biological Systems  

Microsoft Academic Search

The transient and steady-state behavior of a reversible covalent modification system is examined. When the modifying enzymes operate outside the region of first-order kinetics, small percentage changes in the concentration of the effector controlling either of the modifying enzymes can give much larger percentage changes in the amount of modified protein. This amplification of the response to a stimulus can

Albert Goldbeter; Daniel E. Koshland

1981-01-01

306

Amplified terminal protection assay of small molecule/protein interactions via a highly characteristic solid-state Ag/AgCl process.  

PubMed

In this work, we describe a new sensitive strategy for electrochemical detection of protein via small molecule/protein interactions. This assay is based on a terminal protection mechanism that small molecule-linked single-stranded DNA (ssDNA) is protected against hydrolysis by exonuclease I when the target protein is captured by the corresponding small molecule recognition element. Positively charged gold nanoparticles (AuNPs) are attached to the termini-protected and negatively charged ssDNA through electrostatic interactions. Subsequent AuNP-catalyzed silver enhancement followed by a highly characteristic and sensitive solid-state Ag/AgCl process is introduced to the sensing platform to amplify the signal output. By combining the amplification ability resulting from the silver deposition on the surface-captured AuNPs with the inherent high sensitivity of the electrochemical solid-state Ag/AgCl process, our method expands its range to the detection of macromolecules that bind to specific small molecules and enables low picomolar detection of protein. As a model of biotin/streptavidin interaction, a detection limit of 10 pM for streptavidin is readily achieved with desirable sensitivity and specificity, which indicates that the terminal protection assay coupled with the electrochemical solid-state Ag/AgCl process can offer a promising platform for the determination of various of types of proteins or small molecule-protein interactions. PMID:23274192

Wang, Qiong; Jiang, Bingying; Xu, Jin; Xie, Jiaqing; Xiang, Yun; Yuan, Ruo; Chai, Yaqin

2013-05-15

307

Operational Amplifiers Animation/Presentation  

NSDL National Science Digital Library

This presentation, by Arizona State University, addresses operational amplifiers; their structure, construction and applications of the technology. The site is broken down into ten sections; these are: an introduction, terminal connections, op-amp internals, ideal op-amp equations, circuit analysis example, voltage follower, inverting configuration, non-inverting configuration, differentiators, and integrators. Overall, the site is flashy, but still informative presentation of this technology.

Holbert, Keith E.

2010-03-18

308

338-GHz Semiconductor Amplifier Module  

NASA Technical Reports Server (NTRS)

Research findings were reported from an investigation of new gallium nitride (GaN) monolithic millimeter-wave integrated circuit (MMIC) power amplifiers (PAs) targeting the highest output power and the highest efficiency for class-A operation in W-band (75-110 GHz). W-band PAs are a major component of many frequency multiplied submillimeter-wave LO signal sources. For spectrometer arrays, substantial W-band power is required due to the passive lossy frequency multipliers.

Samoska, Lorene A.; Gaier, Todd C.; Soria, Mary M.; Fung, King Man; Rasisic, Vesna; Deal, William; Leong, Kevin; Mei, Xiao Bing; Yoshida, Wayne; Liu, Po-Hsin; Uyeda, Jansen; Lai, Richard

2010-01-01

309

High power gas laser amplifier  

DOEpatents

A high power output CO.sub.2 gas laser amplifier having a number of sections, each comprising a plurality of annular pumping chambers spaced around the circumference of a vacuum chamber containing a cold cathode, gridded electron gun. The electron beam from the electron gun ionizes the gas lasing medium in the sections. An input laser beam is split into a plurality of annular beams, each passing through the sections comprising one pumping chamber.

Leland, Wallace T. (Los Alamos, NM); Stratton, Thomas F. (Los Alamos, NM)

1981-01-01

310

High temperature current mirror amplifier  

Microsoft Academic Search

Disclosed is a high temperature current mirror amplifier having biasing means in the transdiode connection of the input transistor for producing a voltage to maintain the base-collector junction reversed-biased and a current means for maintaining a current through the biasing means at high temperatures so that the base-collector junction of the input transistor remained reversed-biased. For accuracy, a second current

1984-01-01

311

High temperature current mirror amplifier  

Microsoft Academic Search

A high temperature current mirror amplifier having biasing means in the transdiode connection of the input transistor for producing a voltage to maintain the base-collector junction reversed-biased and a current means for maintaining a current through the biasing means at high temperatures so that the base-collector junction of the input transistor remained reversed-biased. For accuracy, a second current mirror is

Raymond B

1984-01-01

312

Cryogenic CMOS circuits for single charge digital readout.  

SciTech Connect

The readout of a solid state qubit often relies on single charge sensitive electrometry. However the combination of fast and accurate measurements is non trivial due to large RC time constants due to the electrometers resistance and shunt capacitance from wires between the cold stage and room temperature. Currently fast sensitive measurements are accomplished through rf reflectrometry. I will present an alternative single charge readout technique based on cryogenic CMOS circuits in hopes to improve speed, signal-to-noise, power consumption and simplicity in implementation. The readout circuit is based on a current comparator where changes in current from an electrometer will trigger a digital output. These circuits were fabricated using Sandia's 0.35 {micro}m CMOS foundry process. Initial measurements of comparators with an addition a current amplifier have displayed current sensitivities of < 1nA at 4.2K, switching speeds up to {approx}120ns, while consuming {approx}10 {micro}W. I will also discuss an investigation of noise characterization of our CMOS process in hopes to obtain a better understanding of the ultimate limit in signal to noise performance.

Gurrieri, Thomas M.; Longoria, Erin Michelle; Eng, Kevin; Carroll, Malcolm S.; Hamlet, Jason R.; Young, Ralph Watson

2010-03-01

313

Development of a HgCdTe photomixer and impedance matched GaAs FET amplifier  

NASA Technical Reports Server (NTRS)

A research program for the development of a 10.6 micron HgCdTe photodiode/GaAs field effect transistor amplifier package for use at cryogenic temperatures (77k). The photodiode/amplifier module achieved a noise equivalent power per unit bandwidth of 5.7 times 10 to the 20th power W/Hz at 2.0 GHz. The heterodyne sensitivity of the HgCdTe photodiode was improved by designing and building a low noise GaAs field effect transistor amplifier operating at 77K. The Johnson noise of the amplifier was reduced at 77K, and thus resulted in an increased photodiode heterodyne sensitivity.

Shanley, J. F.; Paulauskas, W. A.; Taylor, D. R.

1982-01-01

314

High power regenerative laser amplifier  

DOEpatents

A regenerative amplifier design capable of operating at high energy per pulse, for instance, from 20-100 Joules, at moderate repetition rates, for instance from 5-20 Hertz is provided. The laser amplifier comprises a gain medium and source of pump energy coupled with the gain medium; a Pockels cell, which rotates an incident beam in response to application of a control signal; an optical relay system defining a first relay plane near the gain medium and a second relay plane near the rotator; and a plurality of reflectors configured to define an optical path through the gain medium, optical relay and Pockels cell, such that each transit of the optical path includes at least one pass through the gain medium and only one pass through the Pockels cell. An input coupler, and an output coupler are provided, implemented by a single polarizer. A control circuit coupled to the Pockels cell generates the control signal in timed relationship with the input pulse so that the input pulse is captured by the input coupler and proceeds through at least one transit of the optical path, and then the control signal is applied to cause rotation of the pulse to a polarization reflected by the polarizer, after which the captured pulse passes through the gain medium at least once more and is reflected out of the optical path by the polarizer before passing through the rotator again to provide an amplified pulse.

Miller, John L. (Livermore, CA); Hackel, Lloyd A. (Livermore, CA); Dane, Clifford B. (Dublin, CA); Zapata, Luis E. (Livermore, CA)

1994-01-01

315

High power regenerative laser amplifier  

DOEpatents

A regenerative amplifier design capable of operating at high energy per pulse, for instance, from 20-100 Joules, at moderate repetition rates, for instance from 5-20 Hertz is provided. The laser amplifier comprises a gain medium and source of pump energy coupled with the gain medium; a Pockels cell, which rotates an incident beam in response to application of a control signal; an optical relay system defining a first relay plane near the gain medium and a second relay plane near the rotator; and a plurality of reflectors configured to define an optical path through the gain medium, optical relay and Pockels cell, such that each transit of the optical path includes at least one pass through the gain medium and only one pass through the Pockels cell. An input coupler, and an output coupler are provided, implemented by a single polarizer. A control circuit coupled to the Pockels cell generates the control signal in timed relationship with the input pulse so that the input pulse is captured by the input coupler and proceeds through at least one transit of the optical path, and then the control signal is applied to cause rotation of the pulse to a polarization reflected by the polarizer, after which the captured pulse passes through the gain medium at least once more and is reflected out of the optical path by the polarizer before passing through the rotator again to provide an amplified pulse. 7 figures.

Miller, J.L.; Hackel, L.A.; Dane, C.B.; Zapata, L.E.

1994-02-08

316

Ultra low-noise charge coupled device  

NASA Technical Reports Server (NTRS)

Special purpose CCD designed for ultra low-noise imaging and spectroscopy applications that require subelectron read noise floors, wherein a non-destructive output circuit operating near its 1/f noise regime is clocked in a special manner to read a single pixel multiple times. Off-chip electronics average the multiple values, reducing the random noise by the square-root of the number of samples taken. Noise floors below 0.5 electrons rms are possible in this manner. In a preferred embodiment of the invention, a three-phase CCD horizontal register is used to bring a pixel charge packet to an input gate adjacent a floating gate amplifier. The charge is then repeatedly clocked back and forth between the input gate and the floating gate. Each time the charge is injected into the potential well of the floating gate, it is sensed non-destructively. The floating gate amplifier is provided with a reference voltage of a fixed value and a pre-charge gate for resetting the amplifier between charge samples to a constant gain. After the charge is repeatedly sampled a selected number of times, it is transferred by means of output gates, back into the horizontal register, where it is clocked in a conventional manner to a diffusion MOSFET amplifier. It can then be either sampled (destructively) one more time or otherwise discarded.

Janesick, James R. (Inventor)

1993-01-01

317

Log amplifier with pole-zero compensation  

DOEpatents

A logarithmic amplifier circuit provides pole-zero compensation for improved stability and response time over 6-8 decades of input signal frequency. The amplifier circuit includes a first operational amplifier with a first feedback loop which includes a second, inverting operational amplifier in a second feedback loop. The compensated output signal is provided by the second operational amplifier with the log elements, i.e., resistors, and the compensating capacitors in each of the feedback loops having equal values so that each break point or pole is offset by a compensating break point or zero.

Brookshier, William (Downers Grove, IL)

1987-01-01

318

High power RF solid state power amplifier system  

NASA Technical Reports Server (NTRS)

A high power, high frequency, solid state power amplifier system includes a plurality of input multiple port splitters for receiving a high-frequency input and for dividing the input into a plurality of outputs and a plurality of solid state amplifier units. Each amplifier unit includes a plurality of amplifiers, and each amplifier is individually connected to one of the outputs of multiport splitters and produces a corresponding amplified output. A plurality of multiport combiners combine the amplified outputs of the amplifiers of each of the amplifier units to a combined output. Automatic level control protection circuitry protects the amplifiers and maintains a substantial constant amplifier power output.

Sims, III, William Herbert (Inventor); Chavers, Donald Gregory (Inventor); Richeson, James J. (Inventor)

2011-01-01

319

HIGH AVERAGE POWER OPTICAL FEL AMPLIFIERS.  

SciTech Connect

Historically, the first demonstration of the optical FEL was in an amplifier configuration at Stanford University [l]. There were other notable instances of amplifying a seed laser, such as the LLNL PALADIN amplifier [2] and the BNL ATF High-Gain Harmonic Generation FEL [3]. However, for the most part FELs are operated as oscillators or self amplified spontaneous emission devices. Yet, in wavelength regimes where a conventional laser seed can be used, the FEL can be used as an amplifier. One promising application is for very high average power generation, for instance FEL's with average power of 100 kW or more. The high electron beam power, high brightness and high efficiency that can be achieved with photoinjectors and superconducting Energy Recovery Linacs (ERL) combine well with the high-gain FEL amplifier to produce unprecedented average power FELs. This combination has a number of advantages. In particular, we show that for a given FEL power, an FEL amplifier can introduce lower energy spread in the beam as compared to a traditional oscillator. This properly gives the ERL based FEL amplifier a great wall-plug to optical power efficiency advantage. The optics for an amplifier is simple and compact. In addition to the general features of the high average power FEL amplifier, we will look at a 100 kW class FEL amplifier is being designed to operate on the 0.5 ampere Energy Recovery Linac which is under construction at Brookhaven National Laboratory's Collider-Accelerator Department.

BEN-ZVI, ILAN, DAYRAN, D.; LITVINENKO, V.

2005-08-21

320

Direct solar-pumped iodine laser amplifier  

NASA Technical Reports Server (NTRS)

This semiannual progress report covers the period from April 1, 1985 to Sept. 30, 1985 under NASA grant NAS1-441 entitled direct solar pumped iodine laser amplifier. During this period the parametric studies of the iodine laser oscillator pumped by a Vortek simulator was carried out before the amplifier studies. The amplifier studies are postponed to the extended period following completion of the parametric studies. In addition, the kinetic modeling of a solar pumped iodine laser amplifier, and the experimental work for a solar pumped dye laser amplifier are in progress. This report contains three parts: (1) the radiation characteristics of solar simulator and the parametric characteristics of photodissociation iodine laser continuously pumped by a Vortek solar simulator; (2) kinetic modeling of a solar pumped iodine laser amplifier; and (3) the study of the dye laser amplifier pumped by a Tamarack solar simulator.

Han, K. S.

1985-01-01

321

The spectacular human nose: an amplifier of individual quality?  

PubMed Central

Amplifiers are signals that improve the perception of underlying differences in quality. They are cost free and advantageous to high quality individuals, but disadvantageous to low quality individuals, as poor quality is easier perceived because of the amplifier. For an amplifier to evolve, the average fitness benefit to the high quality individuals should be higher than the average cost for the low quality individuals. The human nose is, compared to the nose of most other primates, extraordinary large, fragile and easily broken—especially in male–male interactions. May it have evolved as an amplifier among high quality individuals, allowing easy assessment of individual quality and influencing the perception of attractiveness? We tested the latter by manipulating the position of the nose tip or, as a control, the mouth in facial pictures and had the pictures rated for attractiveness. Our results show that facial attractiveness failed to be influenced by mouth manipulations. Yet, facial attractiveness increased when the nose tip was artificially centered according to other facial features. Conversely, attractiveness decreased when the nose tip was displaced away from its central position. Our results suggest that our evaluation of attractiveness is clearly sensitive to the centering of the nose tip, possibly because it affects our perception of the face’s symmetry and/or averageness. However, whether such centering is related to individual quality remains unclear. PMID:24765588

Mikalsen, ?se Kristine Rognmo; Yoccoz, Nigel Gilles; Laeng, Bruno

2014-01-01

322

The spectacular human nose: an amplifier of individual quality?  

PubMed

Amplifiers are signals that improve the perception of underlying differences in quality. They are cost free and advantageous to high quality individuals, but disadvantageous to low quality individuals, as poor quality is easier perceived because of the amplifier. For an amplifier to evolve, the average fitness benefit to the high quality individuals should be higher than the average cost for the low quality individuals. The human nose is, compared to the nose of most other primates, extraordinary large, fragile and easily broken-especially in male-male interactions. May it have evolved as an amplifier among high quality individuals, allowing easy assessment of individual quality and influencing the perception of attractiveness? We tested the latter by manipulating the position of the nose tip or, as a control, the mouth in facial pictures and had the pictures rated for attractiveness. Our results show that facial attractiveness failed to be influenced by mouth manipulations. Yet, facial attractiveness increased when the nose tip was artificially centered according to other facial features. Conversely, attractiveness decreased when the nose tip was displaced away from its central position. Our results suggest that our evaluation of attractiveness is clearly sensitive to the centering of the nose tip, possibly because it affects our perception of the face's symmetry and/or averageness. However, whether such centering is related to individual quality remains unclear. PMID:24765588

Mikalsen, Se Kristine Rognmo; Folstad, Ivar; Yoccoz, Nigel Gilles; Laeng, Bruno

2014-01-01

323

Particle-Charge Spectrometer  

NASA Technical Reports Server (NTRS)

An instrument for rapidly measuring the electric charges and sizes (from approximately 1 to approximately 100 micrometers) of airborne particles is undergoing development. Conceived for monitoring atmospheric dust particles on Mars, instruments like this one could also be used on Earth to monitor natural and artificial aerosols in diverse indoor and outdoor settings for example, volcanic regions, clean rooms, powder-processing machinery, and spray-coating facilities. The instrument incorporates a commercially available, low-noise, ultrasensitive charge-sensing preamplifier circuit. The input terminal of this circuit--the gate of a field-effect transistor--is connected to a Faraday-cage cylindrical electrode. The charged particles of interest are suspended in air or other suitable gas that is made to flow along the axis of the cylindrical electrode without touching the electrode. The flow can be channeled and generated by any of several alternative means; in the prototype of this instrument, the gas is drawn along a glass capillary tube (see upper part of figure) coaxial with the electrode. The size of a particle affects its rate of acceleration in the flow and thus affects the timing and shape of the corresponding signal peak generated by the charge-sensing amplifier. The charge affects the magnitude (and thus also the shape) of the signal peak. Thus, the signal peak (see figure) conveys information on both the size and electric charge of a sensed particle. In experiments thus far, the instrument has been found to be capable of measuring individual aerosol particle charges of magnitude greater than 350 e (where e is the fundamental unit of electric charge) with a precision of +/- 150 e. The instrument can sample particles at a rate as high as several thousand per second.

Fuerstenau, Stephen; Wilson, Gregory R.

2008-01-01

324

TA 7.4: A High-Swing 2V CMOSOperational Amplifier with Gain Enhancement usinga Replica Amplifier  

E-print Network

TA 7.4: A High-Swing 2V CMOSOperational Amplifier with Gain Enhancement usinga Replica Amplifier output resistance, butby matching main andreplica amplifiers, high effectiveopen-stageamplifiercircuitdemon- strates gain enhancementfor low-voltage applications. Consider a transconductance amplifier

Lee, Hae-Seung "Harry"

325

Radiating Charge  

NSDL National Science Digital Library

The electric field lines from a point charge evolve in time as the charge moves. Watch radiation propagate outward at the speed of light as you wiggle the charge. Stop a moving charge to see bremsstrahlung (braking) radiation. Explore the radiation patterns as the charge moves with sinusoidal, circular, or linear motion. You can move the charge any way you like, as long as you donāt exceed the speed of light.

Simulations, Phet I.; Dubson, Michael; Paul, Ariel

2013-02-01

326

Amplified fragment length polymorphism versus random amplified polymorphic DNA markers: clonal diversity in Saxifraga cernua.  

PubMed

Random amplified polymorphic DNA (RAPD) markers are sensitive to changes in reaction conditions and may express polymorphisms of nongenetic origin. Taxa with variable chromosome numbers are particularly challenging cases, as differences in DNA content may also influence marker reproducibility. We addressed these problems by comparing RAPD and amplified fragment length polymorphism (AFLP) analyses of clonal identity and relationships in a chromosomally variable arctic plant, the polyploid Saxifraga cernua, which has been thought to be monoclonal over large geographical distances. Fifty-seven plants from four Greenland populations were analysed using a conservative scoring approach. In total, 26 AFLP and 32 RAPD multilocus phenotypes (putative clones) were identified, of which 21 were identical and each of the remaining five AFLP clones was split into two to three very similar RAPD clones. This minor difference can be explained by sampling error and stochastic variation. The pattern observed in Greenland corroborates our previous results from Svalbard, suggesting that rare sexual events in S. cernua are sufficient to maintain high levels of clonal diversity even at small spatial scales. We conclude that although AFLP analysis is superior in terms of efficiency, RAPDs may still be used as reliable markers in small low-tech laboratories. PMID:14653790

Kjųlner, S; Såstad, S M; Taberlet, P; Brochmann, C

2004-01-01

327

Quantum Noise in Amplifiers and Hawking/Dumb-Hole Radiation as Amplifier Noise  

E-print Network

The quantum noise in a linear amplifier is shown to be thermal noise. The theory of linear amplifiers is applied first to the simplest, single or double oscillator model of an amplifier, and then to linear model of an amplifier with continuous fields and input and outputs. Finally it is shown that the thermal noise emitted by black holes first demonstrated by Hawking, and of dumb holes (sonic and other analogs to black holes), arises from the same analysis as for linear amplifiers. The amplifier noise of black holes acting as amplifiers on the quantum fields living in the spacetime surrounding the black hole is the radiation discovered by Hawking. For any amplifier, that quantum noise is completely characterized by the attributes of the system regarded as a classical amplifier, and arises out of those classical amplification factors and the commutation relations of quantum mechanics.

W. G. Unruh

2011-07-13

328

Minimising total energy requirements in amplified links by optimising amplifier spacing.  

PubMed

We investigate the energy optimization (minimization) for amplified links. We show that using the using a well-established analytic nonlinear signal-to-noise ratio noise model that for a simple amplifier model there are very clear, fiber independent, amplifier gains which minimize the total energy requirement. With a generalized amplifier model we establish the spacing for the optimum power per bit as well as the nonlinear limited optimum power. An amplifier spacing corresponding to 13 dB gain is shown to be a suitable compromise for practical amplifiers operating at the optimum nonlinear power. PMID:25321063

Doran, N J; Ellis, A D

2014-08-11

329

Study on the properties and charge generation in dye-sensitized n-TiO 2|dye|p-CuI solid state photovoltaic solar cells  

NASA Astrophysics Data System (ADS)

Transparent semiconducting copper iodide (CuI) films were prepared by XeCl Excimer laser and their characteristics are investigated. These films exhibited optical transmittance over 80% in the wavelength range from 400 to 900 nm and minimum resistivity of about 2 k? cm -1. The optical absorption of the these films shows a remarkable blue shift compared to that of polycrystalline of CuI, which can be explained from the viewpoint formation of ultra fine of CuI grains. The titanium dioxide (TiO 2) films have been prepared by sol-gel method. The properties of pulsed laser deposited CuI and TiO 2 films in power output of n-TiO 2|dye|p-CuI cells is studied. An efficient charge generation is observed through the illumination of TiO 2 layer of the fabricated n-TiO 2|dye|p-CuI solid state photovoltaic solar cells. From the current-voltage characteristics, the fill factor and power conversion efficiency were about of 45 and 3%, respectively. The maximum photo-current of about 12.5 mA/cm 2 and photo-voltage of 475 mV under AM 1.5 conditions were obtained for the n-TiO 2|dye|p-CuI solid states photovoltaic solar cells with good reproducibility. Adsorbed dye molecules to the TiO 2 surface act as a relay, especially under illumination through TiO 2 layer in the wave range region of 300-400 nm.

Rusop, M.; Shirata, T.; Sirimanne, P. M.; Soga, T.; Jimbo, T.; Umeno, M.

2006-08-01

330

Optically amplified detection for biomedical sensing and imaging.  

PubMed

Optical sensing and imaging methods for biomedical applications, such as spectroscopy and laser-scanning fluorescence microscopy, are incapable of performing sensitive detection at high scan rates due to the fundamental trade-off between sensitivity and speed. This is because fewer photons are detected during short integration times and hence the signal falls below the detector noise. Optical postamplification can, however, overcome this challenge by amplifying the collected optical signal after collection and before photodetection. Here we present a theoretical analysis of the sensitivity of high-speed biomedical sensing and imaging systems enhanced by optical postamplifiers. As a case study, we focus on Raman amplifiers because they produce gain at any wavelength within the gain medium's transparency window and are hence suitable for biomedical applications. Our analytical model shows that when limited by detector noise, such optically postamplified systems can achieve a sensitivity improvement of up to 20 dB in the visible to near-infrared spectral range without sacrificing speed. This analysis is expected to be valuable for design of fast real-time biomedical sensing and imaging systems. PMID:24322867

Mahjoubfar, Ata; Goda, Keisuke; Betts, Gary; Jalali, Bahram

2013-10-01

331

A new amplifier for improving piezoelectric actuator linearity based on current switching in precision positioning  

Microsoft Academic Search

Piezoelectric actuators have traditionally been driven by voltage amplifiers. When driven at large voltages these actuators exhibit a significant amount of distortion, known as hysteresis, which may reduce the stability robustness of the system in feedback control applications. Piezoelectric transducers are known to exhibit less hysteresis when driven with current or charge rather than voltage. Despite this advantage, such methods

Changhai Ru; Liguo Chen; Bing Shao; Weibin Rong; Lining Sun

2008-01-01

332

Integrated ytterbium-Raman fiber amplifier.  

PubMed

An integrated ytterbium-Raman fiber amplifier architecture is proposed for power scaling of a Raman fiber laser. It is an ytterbium (Yb) fiber amplifier seeded with a double or multiple wavelength laser and followed by a passive Raman fiber. The bluest wavelength light gets amplified in the Yb fiber and the power is transferred to redder wavelengths in the following Raman fiber. A proof of principle experiment demonstrates a 300 W all-fiber linearly polarized single mode amplifier at 1120 nm with an optical efficiency of 70%, limited only by available pump power. The amplifier consists of 4 m of Yb-doped fiber and 20 m of germanium-doped fiber, and seeded with a laser emitting at 1070 and 1120 nm. The power evolution of the 1070 and 1120 nm light inside the amplifier is investigated, both numerically and experimentally. The possibility of power scaling to over kilowatt levels is discussed. PMID:24686642

Zhang, Lei; Jiang, Huawei; Cui, Shuzhen; Feng, Yan

2014-04-01

333

Multistaged stokes injected Raman capillary waveguide amplifier  

DOEpatents

A multistaged Stokes injected Raman capillary waveguide amplifier for providing a high gain Stokes output signal. The amplifier uses a plurality of optically coupled capillary waveguide amplifiers and one or more regenerative amplifiers to increase Stokes gain to a level sufficient for power amplification. Power amplification is provided by a multifocused Raman gain cell or a large diameter capillary waveguide. An external source of CO.sub.2 laser radiation can be injected into each of the capillary waveguide amplifier stages to increase Raman gain. Devices for injecting external sources of CO.sub.2 radiation include: dichroic mirrors, prisms, gratings and Ge Brewster plates. Alternatively, the CO.sub.2 input radiation to the first stage can be coupled and amplified between successive stages.

Kurnit, Norman A. (Santa Fe, NM)

1980-01-01

334

High-power solid-state amplifiers  

Microsoft Academic Search

High-power amplifiers are needed, particularly in the area of sound reinforcement for public address and auditorium usage. Paralleling a number of amplifiers to obtain the required power level has never been a wholly satisfactory solution. This paper presents the design philosophies and goals achieved in two high-power solid-state amplifiers, rated at 150 and 330 watts, respectively. In addition, there is

L. Garner

1967-01-01

335

Solid-state amplifiers for terahertz electronics  

Microsoft Academic Search

With the fMAX of current generation InP transistors pushing above 1-THz and new transistor scaling in progress, the operational frequency of solid-state amplifiers is being pushed towards THz frequencies. In this paper we present our latest work towards demonstrating THz frequency amplifiers,including measured gain and noise performance of a 0.48 THz low noise amplifier using scaled InP transistors. Initial performance

W. R. Deal

2010-01-01

336

Solid-state amplifiers for terahertz electronics  

Microsoft Academic Search

With the fMAX of current generation InP transistors pushing above 1-THz and new transistor scaling in progress, the operational frequency of solid-state amplifiers is being pushed towards THz frequencies. In this paper we present out latest work towards demonstrating THz frequency amplifiers, including measured gain and noise performance of a 0.48 THz low noise amplifier using scaled InP transistors. Initial

W. R. Deal

2010-01-01

337

Log amplifier with pole-zero compensation  

DOEpatents

A logarithmic amplifier circuit provides pole-zero compensation for improved stability and response time over 6-8 decades of input signal frequency. The amplifer circuit includes a first operational amplifier with a first feedback loop which includes a second, inverting operational amplifier in a second feedstock loop. The compensated output signal is provided by the second operational amplifier with the log elements, i.e., resistors, and the compensating capacitors in each of the feedback loops having equal values so that each break point is offset by a compensating break point or zero.

Brookshier, W.

1985-02-08

338

Signal-Conditioning Amplifier Recorders  

NASA Technical Reports Server (NTRS)

Signal-conditioning amplifier recorders (SCAmpRs) have been proposed as a means of simplifying and upgrading the Kennedy Space Center (KSC) Ground Measurement System (GMS), which is a versatile data-acquisition system that gathers and records a variety of measurement data before and during the launch of a space shuttle. In the present version of the GMS system, signal conditioning amplifiers digitize and transmit data to a VME chassis that multiplexes up to 416 channels. The data is transmitted via a high-speed data bus to a second VME chassis where it is available for snapshots. The data is passed from the second VME chassis to a high-speed data recorder. This process is duplicated for installations at two launch pads and the Vehicle Assembly Building (VAB). Since any failure of equipment in the data path results in loss of data, much of the system is redundant. The architecture of the existing GMS limits expansion or any modification to the system to meet changing requirements because of the cost and time required. A SCAmpR-based system is much more flexible. The basis of the simplification, flexibility, and reliability is the shifting of the recording function to the individual amplifier channels. Each SCAmpR is a self-contained single channel data acquisition system, which in its current implementation, has a data storage capacity of up to 30 minutes when operating at the fastest data sampling rates. The SCAmpR channels are self-configuring and self-calibrating. Multiple SCAmpR channels are ganged on printed circuit boards and mounted in a chassis that provides power, a network hub, and Inter-Range Instrument Group (IRIG) time signals. The SCAmpR channels share nothing except physical mounting on a circuit board. All circuitry is electrically separate for each channel. All that is necessary to complete the data acquisition system is a single master computer tied to the SCAmpR channels by standard network equipment. The size of the data acquisition system dictates the requirements for the specific network equipment.

Medelius, Pedro J.; Taylor, John

2003-01-01

339

Quantum metrology with parametric amplifier-based photon correlation interferometers  

PubMed Central

Conventional interferometers usually utilize beam splitters for wave splitting and recombination. These interferometers are widely used for precision measurement. Their sensitivity for phase measurement is limited by the shot noise, which can be suppressed with squeezed states of light. Here we study a new type of interferometer in which the beam splitting and recombination elements are parametric amplifiers. We observe an improvement of 4.1±0.3?dB in signal-to-noise ratio compared with a conventional interferometer under the same operating condition, which is a 1.6-fold enhancement in rms phase measurement sensitivity beyond the shot noise limit. The improvement is due to signal enhancement. Combined with the squeezed state technique for shot noise suppression, this interferometer promises further improvement in sensitivity. Furthermore, because nonlinear processes are involved in this interferometer, we can couple a variety of different waves and form new types of hybrid interferometers, opening a door for many applications in metrology. PMID:24476950

Hudelist, F.; Kong, Jia; Liu, Cunjin; Jing, Jietai; Ou, Z.Y.; Zhang, Weiping

2014-01-01

340

On-line sample preconcentration using field-amplified stacking injection in microchip capillary electrophoresis.  

PubMed

Previous reports describing sample stacking on microchip capillary electrophoresis (microCE) have regarded the microchip channels as a closed system and treated the bulk flow as in traditional capillary electrophoresis. This work demonstrates that the flows arising from the intersection should be investigated as an open system. It is shown that the pressure-driven flows into or from the branch channels due to bulk velocity mismatch in the main channel should not be neglected but can be used for liquid transportation in the channels. On the basis of these concepts, a sample preconcentration scheme was developed in a commercially available single-cross glass chip for microCE. Similar to field-amplified stacking injection in traditional CE, a low conductivity sample buffer plug was introduced into the separation channel immediately before the negatively charged analyte molecules were injected. The detection sensitivity was improved by 94-, 108-, and 160-fold for fluorescein-5-isothiocyanate, fluorescein disodium, and 5-carboxyfluorescein, respectively, relative to a traditional pinched injection. The calibration curves for fluorescein and 5-carboxyfluorescein demonstrated good linearity in the concentration range (1-60 nM) investigated with acceptable reproducibility of migration time and peak height and area ratios (4-5% RSD). This preconcentration scheme will be of particular significance to the practical use of microCE in the emerging miniaturized analytical instrumentation. PMID:16737230

Gong, Maojun; Wehmeyer, Kenneth R; Limbach, Patrick A; Arias, Francisco; Heineman, William R

2006-06-01

341

A hybrid patch clamp amplifier.  

PubMed

The current-to-voltage convertor used in patch clamping is analyzed for noise generation and the major noise sources determined. A hybrid patch clamp amplifier design is theoretically analyzed. Here it is shown that by differentiation and recombining of signals the original input signal can be reconstructed. Several circuits of this design are described and their performance compared. The optimal signal detection obtained for a 1 ms current pulse width with a signal-to-noise ratio of 1 is 0.025 pA. In these circuits, high frequency attenuation is readily accomplished with a single control. In addition, compensation for the transients which occur with step control voltages is effectively accomplished. With this circuitry, it is shown that for most patch clamp situations, the minimum pulse width and current which can be detected is determined by the patch clamp seal resistance. PMID:2761298

Strickholm, A

1989-07-01

342

SQUID Amplifier System for Vibrating Wire Resonators  

Microsoft Academic Search

We describe a simple coupling scheme of superconducting vibrating wire resonators to a SQUID amplifier for achieving supreme signal to noise characteristics. Our construction resulted in a gain factor near 108?0\\/V at 1kHz with an amplifier noise level of about 20 ??0\\/\\u000a

J. Martikainen; J. T. Tuoriniemi

2001-01-01

343

Discrete component S-band power amplifier  

NASA Technical Reports Server (NTRS)

A spacecraft S-band power amplifier for Nimbus satellite is reported that achieves stability by use of moderate Q input and output circuits. The discrete component amplifier uses distributed inductance and small piston capacitors for resonance and impedance matching of the transistor to 50 ohm input and output.

Block, A. F.

1972-01-01

344

Design of a 250 GHz gyrotron amplifier  

E-print Network

A design is presented of a 250 GHz, 1 kW gyrotron traveling wave tube (gyro-TWT) amplifier with gain exceeding 50 dB. Calculations show that the amplifier will operate at 32 kV, 1 A with a saturated gain of 60 dB, an output ...

Nanni, Emilio A. (Emilio Alessandro)

2010-01-01

345

Amplified Piezoelectric Actuators: Static & Dynamic Applications  

Microsoft Academic Search

Amplified Piezoelectric Actuators offer the advantage of large deformation (up to 8%) and large strokes. Because of a prestress applied to the piezo ceramics and an efficient mechanical amplifier, they can produce large strokes both in static and dynamic conditions including resonance. For these reasons, these actuators can be used for micro positioning, structure shaping, structure active damping, vibration generation,

Frank Claeyssen; R. Le Letty; F. Barillot; O. Sosnicki

2007-01-01

346

Diamond Amplified Photocathodes John Smedley1  

E-print Network

acting as a barrier between the primary cathode and the cavity. Synthetic diamond has exhibited secondaryDiamond Amplified Photocathodes John Smedley1 , Ilan Ben-Zvi1 , Jen Bohon2 , Xiangyun Chang1 protecting the cathode from the accelerator. The amplifier is a thin diamond wafer which converts energetic

347

Subcritical Neutron Amplifier Based on Enriched Uranium  

Microsoft Academic Search

The present work is devoted to an investigation of the properties of a subcritical system consisting of enriched uranium, an amplifier of a neutron flux from an external source, and a power amplifier, depending on the composition of the system and the energy of the neutrons from the source [1?3]. The geometric size of the assembly was determined from the

V. A. Babenko; L. L. Enkovskii; V. N. Pavlovich; E. A. Pupirina

2002-01-01

348

41 GHz 10 Watt Solid State Amplifier  

Microsoft Academic Search

This paper describes the results of the study, design, development and test of a 10-watt, 41 GHz solid state amplifier employing rectangular waveguide resonant cavity mode combining of high frequency diodes. This development effort is of significance because it extends beyond 40 GHz the ability to design high power, broadband, multistage amplifiers with reasonable efficiencies suitable for spacecraft applications. Specifically,

D. W. Mooney; F. J. Bayuk

1982-01-01

349

Linear magnetic flux amplifier D. S. Golubovia  

E-print Network

Physics and Chemistry, Nanoscale Superconductivity and Magnetism Group, Laboratory for Solid State PhysicsLinear magnetic flux amplifier D. S. Golubovia and V. V. Moshchalkov INPAC--Institute for Nanoscale that it is feasible to design a linear magnetic flux amplifier for applications in superconducting quantum

Moshchalkov, Victor V.

350

COMPARISON OF LINEAR AND SWITCHING DRIVE AMPLIFIERS FOR PIEZOELECTRIC ACTUATORS  

Microsoft Academic Search

The power requirements imposed on the amplifier by piezoelectric actuators is discussed. We consider a two-degree-of-freedom mechanical system driven by a piezoelectric stack for the purpose of analyzing power flow and power dissipation of four amplifiers. Two of the amplifiers are benchtop linear amplifiers. The other two amplifiers are based on switching topologies. The power consumption of all four of

Douglas K. Lindner; Molly Zhu; Nikola Vujic; Donald J. Leo

351

Comparison of Fast Amplifiers for Diamond Detectors  

E-print Network

The development of Chemical Vapour Deposition (CVD) diamond detectors requests for novel signal amplifiers, capable to match the superb signal-to-noise ratio and timing response of these detectors. Existing amplifiers are still far away from this goal and are the dominant contributors to the overall system noise and the main source of degradation of the energy and timing resolution. We tested a number of commercial amplifiers designed for diamond detector readout to identify the best solution for a particular application. This application required a deposited energy threshold below 100 keV and timing resolution of the order of 200 ps at 200 keV. None of tested amplifiers satisfies these requirements. The best solution to such application found to be the Cividec C6 amplifier, which allows 100 keV minimal threshold, but its coincidence timing resolution at 200 keV is as large as 1.2 ns.

M. Osipenko; S. Minutoli; P. Musico; M. Ripani; B. Caiffi; A. Balbi; G. Ottonello; S. Argirņ; S. Beolč; N. Amapane; M. Masera; G. Mila

2013-10-03

352

Post pulse shutter for laser amplifier  

DOEpatents

Apparatus and method for quickly closing off the return path for an amplified laser pulse at the output of an amplifier so as to prevent damage to amplifiers and other optical components appearing earlier in the chain by the return of an amplified pulse. The apparatus consists of a fast retropulse or post pulse shutter to suppress target reflection and/or beam return. This is accomplished by either quickly placing a solid across the light transmitting aperture of a component in the chain, such as a spatial filter pinhole, or generating and directing a plasma with sufficiently high density across the aperture, so as to, in effect, close the aperture to the returning amplified energy pulse.

Bradley, Laird P. [Livermore, CA; Carder, Bruce M. [Antioch, CA; Gagnon, William L. [Berkeley, CA

1981-03-17

353

Post pulse shutter for laser amplifier  

DOEpatents

Disclosed are an apparatus and method for quickly closing off the return path for an amplified laser pulse at the output of an amplifier so as to prevent damage to amplifiers and other optical components appearing earlier in the chain by the return of an amplified pulse. The apparatus consists of a fast retropulse or post pulse shutter to suppress target reflection and/or beam return. This is accomplished by either quickly placing a solid across the light transmitting aperture of a component in the chain, such as a spatial filter pinhole, or generating and directing a plasma with sufficiently high density across the aperture, so as to, in effect, close the aperture to the returning amplified energy pulse. 13 figs.

Bradley, L.P.; Carder, B.M.; Gagnon, W.L.

1981-03-17

354

Attenuation compensation in distributed amplifier design  

NASA Astrophysics Data System (ADS)

A high-gain common-gate FET that presents at its drain a broadband impedance characterized by a (frequency-dependent) negative resistance and a capacitance is examined theoretically and experimentally. Loading the input and/or the output lines of a distributed amplifier with this circuit reduces the signl losses, leading to an increase in the allowed number of active devices and an increase in the gain-bandwidth and gain-maximum-frequency products. The cascode circuit, a related loss-reduction network used in distributed amplifiers, is also evaluated. Several designs employing the common-gate FET loss-compensating circuit and/or the cascode amplifying circuit are compared to a conventional distributed amplifier optimized for gain-bandwidth product. Simulated gain-maximum-operating-frequency product increases of 27 percent to 245 percent are shown. The increase in single-stage amplifier gain provided by this technique often results in (proportionally) higher maximum output power.

Deibele, Steve; Beyer, James B.

1989-09-01

355

Dual-range linearized transimpedance amplifier system  

DOEpatents

A transimpedance amplifier system is disclosed which simultaneously generates a low-gain output signal and a high-gain output signal from an input current signal using a single transimpedance amplifier having two different feedback loops with different amplification factors to generate two different output voltage signals. One of the feedback loops includes a resistor, and the other feedback loop includes another resistor in series with one or more diodes. The transimpedance amplifier system includes a signal linearizer to linearize one or both of the low- and high-gain output signals by scaling and adding the two output voltage signals from the transimpedance amplifier. The signal linearizer can be formed either as an analog device using one or two summing amplifiers, or alternately can be formed as a digital device using two analog-to-digital converters and a digital signal processor (e.g. a microprocessor or a computer).

Wessendorf, Kurt O. (Albuquerque, NM)

2010-11-02

356

Take Charge!  

NSDL National Science Digital Library

Students come to understand static electricity by learning about the nature of electric charge, and different methods for charging objects. In a hands-on activity, students induce an electrical charge on various objects, and experiment with electrical repulsion and attraction.

Integrated Teaching And Learning Program

357

CMOS Optoelectronic Lock-In Amplifier With Integrated Phototransistor Array.  

PubMed

We describe the design and development of an optoelectronic lock-in amplifier (LIA) for optical sensing and spectroscopy applications. The prototype amplifier is fabricated using Taiwan Semiconductor Manufacturing Co. complementary metal-oxide semiconductor 0.35-?m technology and uses a phototransistor array (total active area is 400 ?m × 640?m) to convert the incident optical signals into electrical currents. The photocurrents are then converted into voltage signals using a transimpedance amplifier for subsequent convenient signal processing by the LIA circuitry. The LIA is optimized to be operational at 20-kHz modulation frequency but is operational in the frequency range from 13 kHz to 25 kHz. The system is tested with a light-emitting diode (LED) as the light source. The noise and signal distortions are suppressed with filters and a phase-locked loop (PLL) implemented in the LIA. The output dc voltage of the LIA is proportional to the incident optical power. The minimum measured dynamic reserve and sensitivity are 1.31 dB and 34 mV/?W, respectively. The output versus input relationship has shown good linearity. The LIA consumes an average power of 12.79 mW with a 3.3-V dc power supply. PMID:23853373

An Hu; Chodavarapu, Vamsy P

2010-10-01

358

SQUID amplifiers for infrared detectors and other applications  

SciTech Connect

The advantages of superconducting processing circuitry for focal plane arrays include low power consumption and the possibility of integrating processing circuitry and detectors on the same substrate. The latter configuration allows for reduction in the number of leads to the readout system and therefore removes a significant bottle neck to processing the massive quantities of data coming from large IR FPAs. All signal processing steps may be executed with superconducting circuit elements. Amplification in superconducting circuitry is performed with the SQUID (Superconducting Quantum Interference Device) amplifier. The present phase I SBIR is being used to investigate a scheme for multiplexing many inputs into one SQUID amplifier. This will reduce the number of SQUID amplifiers needed which is a significant improvement because typical high-gain, multiturn-input SQUIDs are the largest element of superconductivity circuitry. The anticipated payoff of this research is in shrinking the size needed for superconducting circuitry that will be integrated onto IR FPA's. In addition, this method should add very little or no noise to the intrinsic detector noise, thus avoiding any degradation in sensitivity when individual detectors are integrated into the array.

Osterman, D.

1990-12-14

359

Identification of druggable cancer driver genes amplified across TCGA datasets.  

PubMed

The Cancer Genome Atlas (TCGA) projects have advanced our understanding of the driver mutations, genetic backgrounds, and key pathways activated across cancer types. Analysis of TCGA datasets have mostly focused on somatic mutations and translocations, with less emphasis placed on gene amplifications. Here we describe a bioinformatics screening strategy to identify putative cancer driver genes amplified across TCGA datasets. We carried out GISTIC2 analysis of TCGA datasets spanning 16 cancer subtypes and identified 486 genes that were amplified in two or more datasets. The list was narrowed to 75 cancer-associated genes with potential "druggable" properties. The majority of the genes were localized to 14 amplicons spread across the genome. To identify potential cancer driver genes, we analyzed gene copy number and mRNA expression data from individual patient samples and identified 42 putative cancer driver genes linked to diverse oncogenic processes. Oncogenic activity was further validated by siRNA/shRNA knockdown and by referencing the Project Achilles datasets. The amplified genes represented a number of gene families, including epigenetic regulators, cell cycle-associated genes, DNA damage response/repair genes, metabolic regulators, and genes linked to the Wnt, Notch, Hedgehog, JAK/STAT, NF-KB and MAPK signaling pathways. Among the 42 putative driver genes were known driver genes, such as EGFR, ERBB2 and PIK3CA. Wild-type KRAS was amplified in several cancer types, and KRAS-amplified cancer cell lines were most sensitive to KRAS shRNA, suggesting that KRAS amplification was an independent oncogenic event. A number of MAP kinase adapters were co-amplified with their receptor tyrosine kinases, such as the FGFR adapter FRS2 and the EGFR family adapters GRB2 and GRB7. The ubiquitin-like ligase DCUN1D1 and the histone methyltransferase NSD3 were also identified as novel putative cancer driver genes. We discuss the patient tailoring implications for existing cancer drug targets and we further discuss potential novel opportunities for drug discovery efforts. PMID:24874471

Chen, Ying; McGee, Jeremy; Chen, Xianming; Doman, Thompson N; Gong, Xueqian; Zhang, Youyan; Hamm, Nicole; Ma, Xiwen; Higgs, Richard E; Bhagwat, Shripad V; Buchanan, Sean; Peng, Sheng-Bin; Staschke, Kirk A; Yadav, Vipin; Yue, Yong; Kouros-Mehr, Hosein

2014-01-01

360

Identification of Druggable Cancer Driver Genes Amplified across TCGA Datasets  

PubMed Central

The Cancer Genome Atlas (TCGA) projects have advanced our understanding of the driver mutations, genetic backgrounds, and key pathways activated across cancer types. Analysis of TCGA datasets have mostly focused on somatic mutations and translocations, with less emphasis placed on gene amplifications. Here we describe a bioinformatics screening strategy to identify putative cancer driver genes amplified across TCGA datasets. We carried out GISTIC2 analysis of TCGA datasets spanning 14 cancer subtypes and identified 461 genes that were amplified in two or more datasets. The list was narrowed to 73 cancer-associated genes with potential “druggable” properties. The majority of the genes were localized to 14 amplicons spread across the genome. To identify potential cancer driver genes, we analyzed gene copy number and mRNA expression data from individual patient samples and identified 40 putative cancer driver genes linked to diverse oncogenic processes. Oncogenic activity was further validated by siRNA/shRNA knockdown and by referencing the Project Achilles datasets. The amplified genes represented a number of gene families, including epigenetic regulators, cell cycle-associated genes, DNA damage response/repair genes, metabolic regulators, and genes linked to the Wnt, Notch, Hedgehog, JAK/STAT, NF-KB and MAPK signaling pathways. Among the 40 putative driver genes were known driver genes, such as EGFR, ERBB2 and PIK3CA. Wild-type KRAS was amplified in several cancer types, and KRAS-amplified cancer cell lines were most sensitive to KRAS shRNA, suggesting that KRAS amplification was an independent oncogenic event. A number of MAP kinase adapters were co-amplified with their receptor tyrosine kinases, such as the FGFR adapter FRS2 and the EGFR family adapter GRB7. The ubiquitin-like ligase DCUN1D1 and the histone methyltransferase NSD3 were also identified as novel putative cancer driver genes. We discuss the patient tailoring implications for existing cancer drug targets and we further discuss potential novel opportunities for drug discovery efforts. PMID:24874471

Chen, Ying; McGee, Jeremy; Chen, Xianming; Doman, Thompson N.; Gong, Xueqian; Zhang, Youyan; Hamm, Nicole; Ma, Xiwen; Higgs, Richard E.; Bhagwat, Shripad V.; Buchanan, Sean; Peng, Sheng-Bin; Staschke, Kirk A.; Yadav, Vipin; Yue, Yong; Kouros-Mehr, Hosein

2014-01-01

361

Small amplified RNA-SAGE.  

PubMed

Serial analysis of gene expression (SAGE) is a powerful genome-wide analytic tool to determine expression profiles. Since its description in 1995 by Victor Velculescu et al., SAGE has been widely used. Recently, the efficiency of the method has been emphasized as a means to identify novel transcripts or genes that are difficult to identify by conventional methods. SAGE is based on the principle that a 10-base pair (bp) cDNA fragment contains sufficient information to unambiguously identify a transcript, provided it is isolated from a defined position within this transcript. Concatenation of these sequence tags allows serial analysis of transcripts by sequencing multiple tags within a single clone. Extraction of sequence data by computer programs provides a list of sequence tags that reflect both qualitatively and quantitatively the gene expression profile. Several modifications to the initial protocol allowed to start from 1 microg total RNA (or 10(5) cells). In order to reduce the amount of input RNA, protocols including extra polymerase chain reaction (PCR) steps were designed. Linear amplification of the mRNA targets might have advantage over PCR by minimizing biases introduced by the amplification step; therefore we devised a SAGE protocol in which a loop of linear amplification of RNA has been included. Our approach, named "small amplified RNA-SAGE" (SAR-SAGE) included a T7 RNA polymerase promoter within an adapter derived from the standard SAGE linker. This allowed transcription of cDNA segments, extending from the last NlaIII site of transcripts to the polyA tail; these small amplified RNAs then serve as template in a classical (micro)SAGE procedure. As the cDNAs are immobilized on oligo(dT) magnetic beads, several rounds of transcription can be performed in succession with the same cDNA preparation, with the potential to increase further the yield in a linear way. Except for the transcription step itself, the present procedure does not introduce any extra enzymatic reaction in the classical SAGE protocol, it is expected to keep the representation biases associated with amplification as low as possible. PMID:14970461

Vilain, Catheline; Vassart, Gilbert

2004-01-01

362

Event-driven charge-coupled device design and applications therefor  

NASA Technical Reports Server (NTRS)

An event-driven X-ray CCD imager device uses a floating-gate amplifier or other non-destructive readout device to non-destructively sense a charge level in a charge packet associated with a pixel. The output of the floating-gate amplifier is used to identify each pixel that has a charge level above a predetermined threshold. If the charge level is above a predetermined threshold the charge in the triggering charge packet and in the charge packets from neighboring pixels need to be measured accurately. A charge delay register is included in the event-driven X-ray CCD imager device to enable recovery of the charge packets from neighboring pixels for accurate measurement. When a charge packet reaches the end of the charge delay register, control logic either dumps the charge packet, or steers the charge packet to a charge FIFO to preserve it if the charge packet is determined to be a packet that needs accurate measurement. A floating-diffusion amplifier or other low-noise output stage device, which converts charge level to a voltage level with high precision, provides final measurement of the charge packets. The voltage level is eventually digitized by a high linearity ADC.

Doty, John P. (Inventor); Ricker, Jr., George R. (Inventor); Burke, Barry E. (Inventor); Prigozhin, Gregory Y. (Inventor)

2005-01-01

363

PH-315 Lab Notes A. La Rosa OPERATIONAL AMPLIFIERS  

E-print Network

PH-315 Lab Notes A. La Rosa OPERATIONAL AMPLIFIERS ___________________________________________________________ 1. THE ROLE OF OPERATIONAL AMPLIFIERS A typical digital data acquisition system uses a transducer or microcontroller (volts). A conditioning circuit composed of operational amplifiers is then use for that purpose

La Rosa, Andres H.

364

21 CFR 882.1835 - Physiological signal amplifier.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Physiological signal amplifier. 882.1835 Section 882.1835... § 882.1835 Physiological signal amplifier. (a) Identification. A physiological signal amplifier is a general purpose device used...

2011-04-01

365

INFORMATION CAPACITY AND POWER EFFICIENCY IN OPERATIONAL TRANSCONDUCTANCE AMPLIFIERS  

E-print Network

INFORMATION CAPACITY AND POWER EFFICIENCY IN OPERATIONAL TRANSCONDUCTANCE AMPLIFIERS Makeswaran. We have applied our method to an operational transconductance amplifier (OTA) and show that measured for particular applications. Examples of such systems include amplifiers recording signals from sensors

Maryland at College Park, University of

366

47 CFR 2.815 - External radio frequency power amplifiers.  

Code of Federal Regulations, 2011 CFR

... External radio frequency power amplifiers. 2.815 Section 2.815 ...External radio frequency power amplifiers. (a) As used in this part, an external radio frequency power amplifier is any device which,...

2011-10-01

367

21 CFR 882.1835 - Physiological signal amplifier.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Physiological signal amplifier. 882.1835 Section 882.1835... § 882.1835 Physiological signal amplifier. (a) Identification. A physiological signal amplifier is a general purpose device used...

2010-04-01

368

21 CFR 882.1835 - Physiological signal amplifier.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Physiological signal amplifier. 882.1835 Section 882.1835... § 882.1835 Physiological signal amplifier. (a) Identification. A physiological signal amplifier is a general purpose device used...

2013-04-01

369

21 CFR 882.1835 - Physiological signal amplifier.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 false Physiological signal amplifier. 882.1835 Section 882.1835... § 882.1835 Physiological signal amplifier. (a) Identification. A physiological signal amplifier is a general purpose device used...

2012-04-01

370

21 CFR 882.1835 - Physiological signal amplifier.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 false Physiological signal amplifier. 882.1835 Section 882.1835... § 882.1835 Physiological signal amplifier. (a) Identification. A physiological signal amplifier is a general purpose device used...

2014-04-01

371

Ph 315 Lab Notes A. La Rosa OPERATIONAL AMPLIFIERS  

E-print Network

Ph 315 Lab Notes A. La Rosa OPERATIONAL AMPLIFIERS ___________________________________________________________ 1. THE ROLE OF OPERATIONAL AMPLIFIERS A typical digital data acquisition system uses a transducer or microcontroller (volts). A conditioning circuit composed of operational amplifiers is then use for that purpose

372

47 CFR 2.815 - External radio frequency power amplifiers.  

Code of Federal Regulations, 2012 CFR

... External radio frequency power amplifiers. 2.815 Section 2.815 ...External radio frequency power amplifiers. (a) As used in this part, an external radio frequency power amplifier is any device which,...

2012-10-01

373

21 CFR 870.2050 - Biopotential amplifier and signal conditioner.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Biopotential amplifier and signal conditioner. 870.2050...Devices § 870.2050 Biopotential amplifier and signal conditioner. (a) Identification. A biopotential amplifier and signal conditioner is a...

2010-04-01

374

47 CFR 2.815 - External radio frequency power amplifiers.  

Code of Federal Regulations, 2013 CFR

... External radio frequency power amplifiers. 2.815 Section 2.815 ...External radio frequency power amplifiers. (a) As used in this part, an external radio frequency power amplifier is any device which,...

2013-10-01

375

21 CFR 870.2050 - Biopotential amplifier and signal conditioner.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Biopotential amplifier and signal conditioner. 870.2050...Devices § 870.2050 Biopotential amplifier and signal conditioner. (a) Identification. A biopotential amplifier and signal conditioner is a...

2013-04-01

376

21 CFR 870.2050 - Biopotential amplifier and signal conditioner.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 false Biopotential amplifier and signal conditioner. 870.2050...Devices § 870.2050 Biopotential amplifier and signal conditioner. (a) Identification. A biopotential amplifier and signal conditioner is a...

2014-04-01

377

Techniques for high-efficiency outphasing power amplifiers  

E-print Network

A trade-off between linearity and efficiency exists in conventional power amplifiers (PAs). The outphase amplifying concept overcomes this trade-off by enabling the use of high efficiency, non-linear power amplifiers for ...

Godoy, Philip (Philip Andrew)

2011-01-01

378

47 CFR 2.815 - External radio frequency power amplifiers.  

Code of Federal Regulations, 2014 CFR

... External radio frequency power amplifiers. 2.815 Section 2.815 ...External radio frequency power amplifiers. (a) As used in this part, an external radio frequency power amplifier is any device which,...

2014-10-01

379

READOUT ASIC FOR 3D POSITION-SENSITIVE DETECTORS.  

SciTech Connect

We describe an application specific integrated circuit (ASIC) for 3D position-sensitive detectors. It was optimized for pixelated CZT sensors, and it measures, corresponding to an ionizing event, the energy and timing of signals from 121 anodes and one cathode. Each channel provides low-noise charge amplification, high-order shaping, along with peak- and timing-detection. The cathode's timing can be measured in three different ways: the first is based on multiple thresholds on the charge amplifier's voltage output; the second uses the threshold crossing of a fast-shaped signal; and the third measures the peak amplitude and timing from a bipolar shaper. With its power of 2 mW per channel the ASIC measures, on a CZT sensor Connected and biased, charges up to 100 fC with an electronic resolution better than 200 e{sup -} rms. Our preliminary spectral measurements applying a simple cathode/mode ratio correction demonstrated a single-pixel resolution of 4.8 keV (0.72 %) at 662 keV, with the electronics and leakage current contributing in total with 2.1 keV.

DE GERONIMO,G.; VERNON, E.; ACKLEY, K.; DRAGONE, A.; FRIED, J.; OCONNOR, P.; HE, Z.; HERMAN, C.; ZHANG, F.

2007-10-27

380

Ultrafast disk lasers and amplifiers  

NASA Astrophysics Data System (ADS)

Disk lasers with multi-kW continuous wave (CW) output power are widely used in manufacturing, primarily for cutting and welding applications, notably in the automotive industry. The ytterbium disk technology combines high power (average and/or peak power), excellent beam quality, high efficiency, and high reliability with low investment and operating costs. Fundamental mode picosecond disk lasers are well established in micro machining at high throughput and perfect precision. Following the world's first market introduction of industrial grade 50 W picosecond lasers (TruMicro 5050) at the Photonics West 2008, the second generation of the TruMicro series 5000 now provides twice the average power (100 W at 1030 nm, or 60 W frequency doubled, green output) at a significantly reduced footprint. Mode-locked disk oscillators achieve by far the highest average power of any unamplified lasers, significantly exceeding the 100 W level in laboratory set-ups. With robust long resonators their multi-microjoule pulse energies begin to compete with typical ultrafast amplifiers. In addition, significant interest in disk technology has recently come from the extreme light laser community, aiming for ultra-high peak powers of petawatts and beyond.

Sutter, Dirk H.; Kleinbauer, Jochen; Bauer, Dominik; Wolf, Martin; Tan, Chuong; Gebs, Raphael; Budnicki, Aleksander; Wagenblast, Philipp; Weiler, Sascha

2012-03-01

381

Multi-pass light amplifier  

NASA Technical Reports Server (NTRS)

A multiple-pass laser amplifier that uses optical focusing between subsequent passes through a single gain medium so that a reproducibly stable beam size is achieved within the gain region. A confocal resonator or White Cell resonator is provided, including two or three curvilinearly shaped mirrors facing each other along a resonator axis and an optical gain medium positioned on the resonator axis between the mirrors (confocal resonator) or adjacent to one of the mirrors (White Cell). In a first embodiment, two mirrors, which may include adjacent lenses, are configured so that a light beam passing through the gain medium and incident on the first mirror is reflected by that mirror toward the second mirror in a direction approximately parallel to the resonator axis. A light beam translator, such as an optical flat of transparent material, is positioned to translate this light beam by a controllable amount toward or away from the resonator axis for each pass of the light beam through the translator. The optical gain medium may be solid-state, liquid or gaseous medium and may be pumped longitudinally or transversely. In a second embodiment, first and second mirrors face a third mirror in a White Cell configuration, and the optical gain medium is positioned at or adjacent to one of the mirrors. Defocusing means and optical gain medium cooling means are optionally provided with either embodiment, to controllably defocus the light beam, to cool the optical gain medium and to suppress thermal lensing in the gain medium.

Plaessmann, Henry (Inventor); Grossman, William M. (Inventor)

1997-01-01

382

A high sensitivity ultralow temperature RF conductance and noise measurement setup  

SciTech Connect

We report on the realization of a high sensitivity RF noise measurement scheme to study small current fluctuations of mesoscopic systems at milli-Kelvin temperatures. The setup relies on the combination of an interferometric amplification scheme and a quarter-wave impedance transformer, allowing the measurement of noise power spectral densities with gigahertz bandwidth up to five orders of magnitude below the amplifier noise floor. We simultaneously measure the high frequency conductance of the sample by derivating a portion of the signal to a microwave homodyne detection. We describe the principle of the setup, as well as its implementation and calibration. Finally, we show that our setup allows to fully characterize a subnanosecond on-demand single electron source. More generally, its sensitivity and bandwidth make it suitable for applications manipulating single charges at GHz frequencies.

Parmentier, F. D.; Mahe, A.; Denis, A.; Berroir, J.-M.; Glattli, D. C.; Placais, B.; Feve, G. [Laboratoire Pierre Aigrain, Ecole Normale Superieure, CNRS UMR 8551, Universite P. et M. Curie, Universite D. Diderot 24, rue Lhomond, 75231 Paris Cedex 05 (France)

2011-01-15

383

An ultra-sensitive wearable accelerometer for continuous heart and lung sound monitoring.  

PubMed

This paper presents a chest-worn accelerometer with high sensitivity for continuous cardio-respiratory sound monitoring. The accelerometer is based on an asymmetrical gapped cantilever which is composed of a bottom mechanical layer and a top piezoelectric layer separated by a gap. This novel structure helps to increase the sensitivity by orders of magnitude compared with conventional cantilever based accelerometers. The prototype with a resonant frequency of 1100Hz and a total weight of 5 gram is designed, constructed and characterized. The size of the prototype sensor is 35mm×18mm×7.8mm (l×w×t). A built-in charge amplifier is used to amplify the output voltage of the sensor. A sensitivity of 86V/g and a noise floor of 40ng/?Hz are obtained. Preliminary tests for recording both cardiac and respiratory signals are carried out on human body and the new sensor exhibits better performance compared with a high-end electronic stethoscope. PMID:23365987

Hu, Yating; Xu, Yong

2012-01-01

384

Molecular Evolution and Diversity inBacillus anthracisas Detected by Amplified Fragment Length Polymorphism Markers  

Microsoft Academic Search

Bacillus anthraciscauses anthrax and represents one of the most molecularly monomorphic bacteria known. We have used AFLP (amplified fragment length polymorphism) DNA markers to analyze 78 B. anthracis isolates and six relatedBacillusspecies for molecular variation. AFLP markers are extremely sensitive to even small sequence variation, using PCR and high-resolution electrophoresis to examine restriction fragments. Using this approach, we examined ca.

PAUL KEIM; ABDULAHI KALIF; JAMES SCHUPP; KAREN HILL; STEVEN E. TRAVIS; KARA RICHMOND; DEBRA M. ADAIR; MARTIN HUGH-JONES; CHERYL R. KUSKE; ANDPAUL JACKSON

1997-01-01

385

Improved detection of alkaloids in crude extracts applying capillary electrophoresis with field amplified sample injection  

Microsoft Academic Search

A simple and effective method for the sensitive detection of alkaloids in crude plant extracts applying capillary electrophoresis with field amplified sample injection (FASI) is described. This method was compared with normal pressure injection for the determination of alkaloids in methanolic extracts from roots of Berberis vulgaris L. (Berberidaceae) and Hydrastis canadensis L. (Ranunculaceae) using a 1:1 mixture of 200

Matthias Unger; Joachim Stöckigt

1997-01-01

386

Amplifying Limited Expert Input to Sanitize Large Network Traces Xin Huang, Fabian Monrose, Michael K. Reiter  

E-print Network

Amplifying Limited Expert Input to Sanitize Large Network Traces Xin Huang, Fabian Monrose, Michael data in packet payloads, motivated by the need to sanitize packets before releasing them (e. Keywords-sanitization; packet payloads; sensitive data I. INTRODUCTION Visibility into packet payloads

Reiter, Michael

387

Multiple turnovers of DNAzyme for amplified detection of ATP and reduced thiol in cell homogenates.  

PubMed

A conveniently amplified DNAzyme-based fluorescence strategy was designed for highly sensitive detection of ATP or reduced thiol based on the introduction of an ATP aptamer or a disulfide bond in the bioconjugates of magnetic nanoparticles (MNP) and polystyrene microsphere-DNAzyme complexes (PSM-DNAzyme). PMID:25429374

Guo, Yingshu; Liu, Jia; Yang, Guangxu; Sun, Xiaofeng; Chen, Hong-Yuan; Xu, Jing-Juan

2015-01-18

388

Cavity enhanced rephased amplified spontaneous emission  

E-print Network

Amplified spontaneous emission is usually treated as an incoherent noise process. Recent theoretical and experimental work using rephasing optical pulses has shown that rephased amplified spontaneous emission (RASE) is a potential source of wide bandwidth time-delayed entanglement. Due to poor echo efficiency the plain RASE protocol doesn't in theory achieve perfect entanglement. Experiments done to date show a very small amount of entanglement at best. Here we show that rephased amplified spontaneous emission can, in principle, produce perfect multimode time-delayed two mode squeezing when the active medium is placed inside a Q-switched cavity.

Lewis A Williamson; Jevon J Longdell

2014-05-20

389

Phase noise in RF and microwave amplifiers.  

PubMed

Understanding amplifier phase noise is a critical issue in many fields of engineering and physics, such as oscillators, frequency synthesis, telecommunication, radar, and spectroscopy; in the emerging domain of microwave photonics; and in exotic fields, such as radio astronomy, particle accelerators, etc. Focusing on the two main types of base noise in amplifiers, white and flicker, the power spectral density of the random phase ?(t) is S?(f) = b(0) + b(-1)/f. White phase noise results from adding white noise to the RF spectrum in the carrier region. For a given RF noise level, b(0) is proportional to the reciprocal of the carrier power P(0). By contrast, flicker results from a near-dc 1/f noise-present in all electronic devices-which modulates the carrier through some parametric effect in the semiconductor. Thus, b(-1) is a parameter of the amplifier, constant in a wide range of P(0). The consequences are the following: Connecting m equal amplifiers in parallel, b(-1) is 1/m times that of one device. Cascading m equal amplifiers, b(-1) is m times that of one amplifier. Recirculating the signal in an amplifier so that the gain increases by a power of m (a factor of m in decibels) as a result of positive feedback (regeneration), we find that b(-1) is m(2) times that of the amplifier alone. The feedforward amplifier exhibits extremely low b(-1) because the carrier is ideally nulled at the input of its internal error amplifier. Starting with an extensive review of the literature, this article introduces a system-oriented model which describes the phase flickering. Several amplifier architectures (cascaded, parallel, etc.) are analyzed systematically, deriving the phase noise from the general model. There follow numerous measurements of amplifiers using different technologies, including some old samples, and in a wide frequency range (HF to microwaves), which validate the theory. In turn, theory and results provide design guidelines and give suggestions for CAD and simulation. To conclude, this article is intended as a tutorial, a review, and a systematic treatise on the subject, supported by extensive experiments. PMID:23221210

Boudot, Rodolphe; Rubiola, Enrico

2012-12-01

390

CHARGE IMBALANCE  

SciTech Connect

The purpose of this article is to review the theory of charge imbalance, and to discuss its relevance to a number of experimental situations. We introduce the concepts of quasiparticle charge and charge imbalance, and discuss the generation and detection of charge imbalance by tunneling. We describe the relaxation of the injected charge imbalance by inelastic scattering processes, and show how the Boltzmann equation can be solved to obtain the steady state quasiparticle distribution and the charge relaxation rate. Details are given of experiments to measure charge imbalance and the charge relaxation rate when inelastic scattering is the predominant relaxation mechanism. Experiments on and theories of other charge relaxation mechanisms are discussed, namely relaxation via elastic scattering in the presence of energy gap anisotropy, or in the presence of a pair breaking mechanism such as magnetic impurities or an applied supercurrent or magnetic field. We describe three other situations in which charge imbalance occurs, namely the resistance of the NS interface, phase slip centers, and the flow of a supercurrent in the presence of a temperature gradient.

Clarke, John

1980-09-01

391

Position sensitivity in gallium arsenide radiation detectors  

SciTech Connect

For several years, the authors have studied the electrical output of GaAs detectors in response to MeV protons. Beams from the Los Alamos National Laboratory`s tandem Van de Graaff, bunched into pulses of about 0.7-ns width, have been used to drive detectors into the current mode, and fast electronics have enabled characterization of the impulse response shapes and the absolute sensitivities. Recently, the authors extended this line of investigation to measure output-charge spectra in response to low-current beams, in which the count rate was low and pulses due to individual ionizing particles were analyzed. The first part of the work was the measurement of spectra of the output charge of the detectors when bombarded by a beam of MeV-energy protons, which was collimated to a diameter of 0.1 mm. The GaAs detector was mounted on a microadjustable stage just behind the collimator, so that the site of irradiation on the detector could be varied. Output pulses originating from the impacts of individual protons were preamplified with charge-sensitive Lecroy 2004 preamplifiers, shaped with Lecroy 2011 amplifiers, and analyzed with a Lecroy 3500 multichannel analyzer. The second part was the measurement of the time response of the detector to a 0.1 mm-collimated bunched proton beam. The proton bunch width was less than 1 ns, during which time many protons struck the detector, driving it into the current mode where individual proton impacts are unresolved. A possible detector design is suggested by the results. In the past, GaAs time response has been improved by doping or radiation damaging, which introduces traps. The tails can be eliminated, but at the cost of a factor of a thousand in main peak sensitivity. It now appears that by masking off the region of the detector near the negative electrode, the tails can be eliminated with only a factor of about ten loss in peak gain.

Harper, R.; Hilko, R.A.

1994-12-31

392

Development of a Broadband NbTiN Traveling Wave Parametric Amplifier for MKID Readout  

NASA Astrophysics Data System (ADS)

The sensitivity of microwave kinetic inductance detectors (MKIDs) using dissipation readout is limited by the noise temperature of the cryogenic amplifier, usually a HEMT with 5 K. A lower noise amplifier is required to improve NEP and reach the photon noise limit at millimeter wavelengths. Eom et al. have proposed a kinetic inductance traveling wave (KIT) parametric amplifier (also called the dispersion-engineered travelling wave kinetic inductance parametric amplifier) that utilizes the nonlinearity with very low dissipation of NbTiN. This amplifier has the promise to achieve quantum limited noise, broad bandwidth, and high dynamic range, all of which are required for ideal MKID dissipation readout. We have designed a KIT amplifier which consists of a 2.2 m long coplanar waveguide transmission line fabricated in a double spiral format, with periodic loadings and impedance transformers at the input/output ports on a 2 by 2 cm Si chip. The design was fabricated with 20 nm NbTiN films. The device has shown over 10 dB of gain from 4 to 11 GHz. We have found the maximum gain is limited by abrupt breakdown at defects in the transmission line in the devices. By cascading two devices, more than 20 dB of gain was achieved from 4.5 to 12.5 GHz, with a peak of 27 dB.

Bockstiegel, C.; Gao, J.; Vissers, M. R.; Sandberg, M.; Chaudhuri, S.; Sanders, A.; Vale, L. R.; Irwin, K. D.; Pappas, D. P.

2014-08-01

393

Charged Condensation  

E-print Network

We consider Bose-Einstein condensation of massive electrically charged scalars in a uniform background of charged fermions. We focus on the case when the scalar condensate screens the background charge, while the net charge of the system resides on its boundary surface. A distinctive signature of this substance is that the photon acquires a Lorentz-violating mass in the bulk of the condensate. Due to this mass, the transverse and longitudinal gauge modes propagate with different group velocities. We give qualitative arguments that at high enough densities and low temperatures a charged system of electrons and helium-4 nuclei, if held together by laboratory devices or by force of gravity, can form such a substance. We briefly discuss possible manifestations of the charged condensate in compact astrophysical objects.

Gregory Gabadadze; Rachel A. Rosen

2007-06-15

394

Real Time Calibration Method for Signal Conditioning Amplifiers  

NASA Technical Reports Server (NTRS)

A signal conditioning amplifier receives an input signal from an input such as a transducer. The signal is amplified and processed through an analog to digital converter and sent to a processor. The processor estimates the input signal provided by the transducer to the amplifier via a multiplexer. The estimated input signal is provided as a calibration voltage to the amplifier immediately following the receipt of the amplified input signal. The calibration voltage is amplified by the amplifier and provided to the processor as an amplified calibration voltage. The amplified calibration voltage is compared to the amplified input signal, and if a significant error exists, the gain and/or offset of the amplifier may be adjusted as necessary.

Medelius, Pedro J. (Inventor); Mata, Carlos T. (Inventor); Eckhoff, Anthony (Inventor); Perotti, Jose (Inventor); Lucena, Angel (Inventor)

2004-01-01

395

RF breakdown effects in microwave power amplifiers  

E-print Network

Electrical stresses in the transistors of high-efficiency switching power amplifiers can lead to hot-electron-induced "breakdown" in these devices. This thesis explores issues related to breakdown in the Transcom TC2571 ...

Arumilli, Gautham Venkat

2007-01-01

396

Operational Amplifier Experiments for the Chemistry Laboratory.  

ERIC Educational Resources Information Center

Provides details of experiments that deal with the use of operational amplifiers and are part of a course in instrumental analysis. These experiments are performed after the completion of a set of electricity and electronics experiments. (DDR)

Braun, Robert D.

1996-01-01

397

Cryogenic Amplifier Based Receivers at Submillimeter Wavelengths  

NASA Technical Reports Server (NTRS)

The operating frequency of InP high electron mobility transistor (HEMT) based amplifiers has moved well in the submillimeter-wave frequencies over the last couple of years. Working amplifiers with usable gain in waveguide packages has been reported beyond 700 GHz. When cooled cryogenically, they have shown substantial improvement in their noise temperature. This has opened up the real possibility of cryogenic amplifier based heterodyne receivers at submillimeter wavelengths for ground-based, air-borne, and space-based instruments for astrophysics, planetary, and Earth science applications. This paper provides an overview of the science applications at submillimeter wavelengths that will benefit from this technology. It also describes the current state of the InP HEMT based cryogenic amplifier receivers at submillimeter wavelengths.

Chattopadhyay, Goutam; Reck, Theodore and; Schlecht, Erich; Lin, Robert; Deal, William

2012-01-01

398

Advanced Concepts in Josephson Junction Reflection Amplifiers  

NASA Astrophysics Data System (ADS)

Low-noise amplification at microwave frequencies has become increasingly important for the research related to superconducting qubits and nanoelectromechanical systems. The fundamental limit of added noise by a phase-preserving amplifier is the standard quantum limit, often expressed as noise temperature . Towards the goal of the quantum limit, we have developed an amplifier based on intrinsic negative resistance of a selectively damped Josephson junction. Here we present measurement results on previously proposed wide-band microwave amplification and discuss the challenges for improvements on the existing designs. We have also studied flux-pumped metamaterial-based parametric amplifiers, whose operating frequency can be widely tuned by external DC-flux, and demonstrate operation at pumping, in contrast to the typical metamaterial amplifiers pumped via signal lines at.

Lähteenmäki, Pasi; Vesterinen, Visa; Hassel, Juha; Paraoanu, G. S.; Seppä, Heikki; Hakonen, Pertti

2014-06-01

399

Ku band low noise parametric amplifier  

NASA Technical Reports Server (NTRS)

A low noise, K sub u-band, parametric amplifier (paramp) was developed. The unit is a spacecraft-qualifiable, prototype, parametric amplifier for eventual application in the shuttle orbiter. The amplifier was required to have a noise temperature of less than 150 K. A noise temperature of less than 120 K at a gain level of 17 db was achieved. A 3-db bandwidth in excess of 350 MHz was attained, while deviation from phase linearity of about + or - 1 degree over 50 MHz was achieved. The paramp operates within specification over an ambient temperature range of -5 C to +50 C. The performance requirements and the operation of the K sub u-band parametric amplifier system are described. The final test results are also given.

1976-01-01

400

Mechanical Amplifier for Translational Kinetic Energy Harvesters  

NASA Astrophysics Data System (ADS)

This paper reports the design, optimization, and test results of a mechanical amplifier coupled to an electromagnetic energy harvester to generate power from low- amplitude (±1 mm) and low-frequency (<5 Hz) vibrations in the presence of large static displacements. When coupled to a translational kinetic energy harvester, the amplifier boosts small vibration amplitudes by as much as 4x while accommodating translational displacements of more than 10x of vibration amplitudes. A complete electromagnetic energy harvester using this mechanical amplifier produces 16x improvement in output power (30 mW vs 1.9 mW without amplifier at 5 Hz), and a high power density of 170 ?W/cm3.

Shahosseini, I.; Najafi, K.

2014-11-01

401

Tester periodically registers dc amplifier characteristics  

NASA Technical Reports Server (NTRS)

Motor-driven switcher-recorder periodically registers the zero drift and gain drift signals of a dc amplifier subjected to changes in environment. A time coding method is used since several measurements are shared on a single recorder trace.

Cree, D.; Wenzel, G. E.

1966-01-01

402

Noise in phase-preserving linear amplifiers  

NASA Astrophysics Data System (ADS)

The purpose of a phase-preserving linear amplifier is to make a small signal larger, so that it can be perceived by instruments incapable of resolving the original signal, while sacrificing as little as possible in signal-to-noise. Quantum mechanics limits how well this can be done: the noise added by the amplifier, referred to the input, must be at least half a quantum at the operating frequency. This well-known quantum limit only constrains the second moments of the added noise. Here we provide the quantum constraints on the entire distribution of added noise: any phasepreserving linear amplifier is equivalent to a parametric amplifier with a physical state ? for the ancillary mode; ? determines the properties of the added noise.

Pandey, Shashank; Jiang, Zhang; Combes, Joshua; Caves, Carlton M.

2014-12-01

403

A novel wideband gyrotron travelling wave amplifier  

E-print Network

We present the design and the experimental results of a novel wideband quasioptical Gyrotron Traveling Wave Tube (gyro-TWT) amplifier and the first Vacuum Electron Device (VED) with a Photonic Band Gap (PBG) structure. The ...

Sirigiri, Jagadishwar R. (Jagadishwar Rao), 1973-

2003-01-01

404

How to characterize the nonlinear amplifier?  

NASA Technical Reports Server (NTRS)

The conception of the amplification of the coherent field is formulated. The definition of the coefficient of the amplification as the relation between the mean value of the field at the output to the value at the input and the definition of the noise as the difference between the number of photons in the output mode and square of the modulus of the mean value of the output amplitude are considered. Using a simple example it is shown that by these definitions the noise of the nonlinear amplifier may be less than the noise of the ideal linear amplifier of the same amplification coefficient. Proposals to search another definition of basic parameters of the nonlinear amplifiers are discussed. This definition should enable us to formulate the universal fundamental lower limit of the noise which should be valid for linear quantum amplifiers as for nonlinear ones.

Kallistratova, Dmitri Kouznetsov; Cotera, Carlos Flores

1994-01-01

405

High bandwidth differential amplifier for shock experimentsa)  

NASA Astrophysics Data System (ADS)

We developed a high bandwidth differential amplifier for gas gun shock experiments of low-resistance metals. The circuit has a bandwidth up to 1 GHz, and is capable of measuring signals of ?1.5 V with a common mode rejection of 250 V. Conductivity measurements of gas gun targets are measured by flowing high currents through the targets. The voltage is measured across the target using a technique similar to a four-point probe. Because of the design of the current source and load, the target voltage is ˜250 V relative to ground. Since the expected voltage change in the target is <1 V, the differential amplifier must have a large common mode rejection. Various amplifying designs are shown, although the increased amplification decreases bandwidth. Bench tests show that the amplifier can withstand significant common mode dc voltage and measure 10 ns, and 50 mV signals.

Ross, P. W.; Tran, V.; Chau, R.

2012-10-01

406

High Bandwidth Differential Amplifier for Shock Experiments  

SciTech Connect

We developed a high bandwidth differential amplifier for gas gun shock experiments. The circuit has a bandwidth up to 1 GHz, and is capable of measuring signals of ?1.5 V with a common mode rejection of 250 V. Conductivity measurements of gas gun targets are measured by flowing high currents through the targets. The voltage is measured across the target using a technique similar to a four-point probe. Because of the design of the current source and load, the target voltage is approximately 250 V relative to ground. Since the expected voltage change in the target is < 1 V, the differential amplifier must have a large common mode rejection. Various amplifying designs are shown, although the increased amplification decreases bandwidth. Bench tests show that the amplifier can withstand significant common mode DC voltage and measure 10 ns, and 50 mV signals.

Ross, P., Tran, V., Chau, R.

2012-10-01

407

High bandwidth differential amplifier for shock experiments.  

PubMed

We developed a high bandwidth differential amplifier for gas gun shock experiments of low-resistance metals. The circuit has a bandwidth up to 1 GHz, and is capable of measuring signals of ?1.5 V with a common mode rejection of 250 V. Conductivity measurements of gas gun targets are measured by flowing high currents through the targets. The voltage is measured across the target using a technique similar to a four-point probe. Because of the design of the current source and load, the target voltage is ?250 V relative to ground. Since the expected voltage change in the target is <1 V, the differential amplifier must have a large common mode rejection. Various amplifying designs are shown, although the increased amplification decreases bandwidth. Bench tests show that the amplifier can withstand significant common mode dc voltage and measure 10 ns, and 50 mV signals. PMID:23126892

Ross, P W; Tran, V; Chau, R

2012-10-01

408

Laser Cooled High-Power Fiber Amplifier  

E-print Network

A theoretical model for laser cooled continuous-wave fiber amplifier is presented. The amplification process takes place in the Tm3+-doped core of the fluoride ZBLAN (ZrF4-BaF2-LaF3-AlF3-NaF) glass fiber. The cooling process takes place in the Yb3+:ZBLAN fiber cladding. It is shown that for each value of the pump power and the amplified signal there is a distribution of the concentration of the Tm3+ along the length of the fiber amplifier, which provides its athermal operation. The influence of a small deviation in the value of the amplified signal on the temperature of the fiber with the fixed distribution of the Tm3+ions in the fiber cladding is investigated.

Nemova, Galina

2009-01-01

409

Capillary Array Waveguide Amplified Fluorescence Detector for mHealth.  

PubMed

Mobile Health (mHealth) analytical technologies are potentially useful for carrying out modern medical diagnostics in resource-poor settings. Effective mHealth devices for underserved populations need to be simple, low cost, and portable. Although cell phone cameras have been used for biodetection, their sensitivity is a limiting factor because currently it is too low to be effective for many mHealth applications, which depend on detection of weak fluorescent signals. To improve the sensitivity of portable phones, a capillary tube array was developed to amplify fluorescence signals using their waveguide properties. An array configured with 36 capillary tubes was demonstrated to have a ~100X increase in sensitivity, lowering the limit of detection (LOD) of mobile phones from 1000 nM to 10 nM for fluorescein. To confirm that the amplification was due to waveguide behavior, we coated the external surfaces of the capillaries with silver. The silver coating interfered with the waveguide behavior and diminished the fluorescence signal, thereby proving that the waveguide behavior was the main mechanism for enhancing optical sensitivity. The optical configuration described here is novel in several ways. First, the use of capillaries waveguide properties to improve detection of weak florescence signal is new. Second we describe here a three dimensional illumination system, while conventional angular laser waveguide illumination is spot (or line), which is functionally one-dimensional illumination, can illuminate only a single capillary or a single column (when a line generator is used) of capillaries and thus inherently limits the multiplexing capability of detection. The planar illumination demonstrated in this work enables illumination of a two dimensional capillary array (e.g. x columns and y rows of capillaries). In addition, the waveguide light propagation via the capillary wall provides a third dimension for illumination along the axis of the capillaries. Such an array can potentially be used for sensitive analysis of multiple fluorescent detection assays simultaneously. The simple phone based capillary array approach presented in this paper is capable of amplifying weak fluorescent signals thereby improving the sensitivity of optical detectors based on mobile phones. This may allow sensitive biological assays to be measured with low sensitivity detectors and may make mHealth practical for many diagnostics applications, especially in resource-poor and global health settings. PMID:24039345

Balsam, Joshua; Bruck, Hugh Alan; Rasooly, Avraham

2013-09-01

410

MMIC Amplifiers for 90 to 130 GHz  

NASA Technical Reports Server (NTRS)

This brief describes two monolithic microwave integrated-circuit (MMIC) amplifier chips optimized to function in the frequency range of 90 to 130 GHz, covering nearly all of F-band (90 - 140 GHz). These amplifiers were designed specifically for local-oscillator units in astronomical radio telescopes such as the Atacama Large Millimeter Array (ALMA). They could also be readily adapted for use in electronic test equipment, automotive radar systems, and communications systems that operate between 90 and 130 GHz.

Samoska, Lorene; Pukala, David; Peralta, Alejandro; Bryerton, Eric; Morgan, Matt; Boyd, T.; Hu, Ming; Schmitz, Adele

2007-01-01

411

OPASYN: a compiler for CMOS operational amplifiers  

Microsoft Academic Search

A silicon compilation system for CMOS operational amplifiers (OPASYN) is discussed. The synthesis system takes as inputs system-level specifications, fabrication-dependent technology parameters, and geometric layout rules. It produces a design-rule-correct compact layout of an optimized operational amplifier. The synthesis proceeds in three stages: (1) heuristic selection of a suitable circuit topology; (2) parametric circuit optimization based on analytic models; and

Han Young Koh; Carlo H. Séquin; Paul R. Gray

1990-01-01

412

A Si bipolar monolithic RF bandpass amplifier  

NASA Astrophysics Data System (ADS)

The application of monolithic inductors to the realization of Si bipolar monolithic RF amplifiers is investigated. As a test vehicle, a bipolar monolithic bandpass amplifier was fabricated and characterized. A 4-nH silicon integrated inductor was used to achieve a peak S21 gain of 8 dB, a simulated noise figure of 6.4 dB, and a matched input impedance of 50 ohm in the frequency range of 1-2 GHz.

Nguyen, Nhat M.; Meyer, Robert G.

1992-01-01

413

Transient gain dynamics in saturated Raman amplifiers  

Microsoft Academic Search

This paper provides a detailed analysis of transient gain dynamics in saturated Raman amplifiers fed by wavelength division multiplexed (WDM) signals. Such dynamics are due to a pump saturation effect, known as pump-mediated signal-to-signal crosstalk, which is equivalent to the well-known cross-gain modulation in EDFAs. We provide for the first time a simple block-diagram model of the Raman amplifier, whose

A. Bononi; M. Papararo; M. Fuochi

2004-01-01

414

A modeling approach of a magnetic amplifier  

NASA Astrophysics Data System (ADS)

New soft magnetic materials made possible the use of the magnetic amplifier technology in designing competitive electric power supplies. This technology is used in the Swedish fighter aircraft Gripen, being also attractive for future more electrical aircraft systems due to the possibility to achieve a compact and robust design. A modeling approach of a magnetic amplifier based on the magnetic hysteresis of the core material is presented here for a common amorphous magnetic alloy. Also to be corresponded to.

Austrin, L.; Krah, J. H.; Engdahl, G.

2004-05-01

415

Mechanically amplified large displacement piezoelectric actuators  

Microsoft Academic Search

This paper deals with large displacement actuators based on mechanically amplified movements of pre-stressed piezoelectric disks. The bridge-type amplifier structures were made of laser cut polymer laminates fold to certain geometries to accomplish enhanced displacement of the input translation. Optimization of the lever lengths and their positions were carried out using computer-assisted design (by AutoCAD) and mathematical calculations (by MATLAB).

J. Juuti; K. Kordįs; R. Lonnakko; V.-P. Moilanen; S. Leppävuori

2005-01-01

416

A strain amplifying piezoelectric MEMS actuator  

Microsoft Academic Search

A micro-scale, high-force, large displacement and low-voltage piezoelectric actuator has been developed using a compact strain amplifying flextensional mechanism. The device is fabricated using an SU-8 beam structure as an external amplifying mechanism for a thin-film PZT strip (area 11.4 × 10-4 cm2, thickness 0.4 µm) sandwiched between Pt top and bottom electrodes. Each actuator 'cell' can be arrayed in

Nicholas J. Conway; Zachary J. Traina; Sang-Gook Kim

2007-01-01

417

A strain amplifying piezoelectric MEMS actuator  

Microsoft Academic Search

A micro-scale, high-force, large displacement and low-voltage piezoelectric actuator has been developed using a compact strain amplifying flextensional mechanism. The device is fabricated using an SU-8 beam structure as an external amplifying mechanism for a thin-film PZT strip (area 11.4 × 10?4 cm2, thickness 0.4 µm) sandwiched between Pt top and bottom electrodes. Each actuator ‘cell’ can be arrayed in

Nicholas J Conway; Zachary J Traina; Sang-Gook Kim

2007-01-01

418

Direct solar-pumped iodine laser amplifier  

NASA Technical Reports Server (NTRS)

This semiannual progress report covers the period from September 1, 1988 to February 28, 1989 under NASA grant NAG-1-441 entitled, Direct Solar-Pumped Iodine Laser Amplifier. During this period, the research effort was concentrated on the solar pumped master oscillator power amplifier (MOPA) system using n-C3F7I. In the experimental work, the amplification measurement was conducted to identify the optimum conditions for amplification of the center's Vortek solar simulator pumped iodine laser amplifier. A modeling effort was also pursued to explain the experimental results in the theoretical work. The amplification measurement of the solar simulator pumped iodine laser amplifier is the first amplification experiment on the continuously pumped amplifier. The small signal amplification of 5 was achieved for the triple pass geometry of the 15 cm long solar simulator pumped amplifier at the n-C3F7I pressure of 20 torr, at the flow velocity of 6 m/sec and at the pumping intensity of 1500 solar constants. The XeCl laser pumped iodine laser oscillator, which was developed in the previous research, was employed as the master oscillator for the amplification measurement. In the theoretical work, the rate equations of the amplifier was established and the small signal amplification was calculated for the solar simulator pumped iodine laser amplifier. The amplification calculated from the kinetic equations with the previously measured rate coefficients reveals very large disagreement with experimental measurement. Moreover, the optimum condition predicted by the kinetic equation is quite discrepant with that measured by experiment. This fact indicates the necessity of study in the measurement of rate coefficients of the continuously pumped iodine laser system.

Han, Kwang S.; Hwang, In Heon; Stock, Larry V.

1989-01-01

419

High-power, solid-state amplifier  

Microsoft Academic Search

Recent advancements in bipolar and divider\\/combiner amplifier technologies allow solid state amplifiers to be configured in such a way that they may operate at high power levels over the L-, S-, and C-bands. Attention is presently given to the module and divider\\/combiner design features required for the achievement of 200-kW peak power at L-band, 70 kW at S-band, and 30

H. Hom; R. McMaster; B. Sanders

1984-01-01

420

Fiske-amplified superfluid interferometry  

SciTech Connect

We report an experimental demonstration of signal amplification for a superfluid {sup 4}He interferometer by allowing the matter waves from two Josephson mass current sources to interact with the resonances within the experimental cell. We characterize the interferometer using an external phase shift and demonstrate a 30-fold enhancement in intrinsic phase sensitivity. We also demonstrate a truly continuous operation of this interference device.

Sato, Yuki [Rowland Institute at Harvard, Harvard University, Cambridge, Massachusetts 02142 (United States)

2010-05-01

421

Can Like Charges Attract Each Other?  

ERIC Educational Resources Information Center

Electroscopes are sensitive instruments useful for investigations of static electricity. They are devices that are used for detecting whether an object is charged or uncharged. They also determine the type of charge. Their operation is based on the principle of like sign charge repulsion.

Balta, Nuri

2012-01-01

422

Robust Randomness Amplifiers: Upper and Lower Bounds  

E-print Network

A recent sequence of works, initially motivated by the study of the nonlocal properties of entanglement, demonstrate that a source of information-theoretically certified randomness can be constructed based only on two simple assumptions: the prior existence of a short random seed and the ability to ensure that two black-box devices do not communicate (i.e. are non-signaling). We call protocols achieving such certified amplification of a short random seed randomness amplifiers. We introduce a simple framework in which we initiate the systematic study of the possibilities and limitations of randomness amplifiers. Our main results include a new, improved analysis of a robust randomness amplifier with exponential expansion, as well as the first upper bounds on the maximum expansion achievable by a broad class of randomness amplifiers. In particular, we show that non-adaptive randomness amplifiers that are robust to noise cannot achieve more than doubly exponential expansion. Finally, we show that a wide class of protocols based on the use of the CHSH game can only lead to (singly) exponential expansion if adversarial devices are allowed the full power of non-signaling strategies. Our upper bound results apply to all known non-adaptive randomness amplifier constructions to date.

Matthew Coudron; Thomas Vidick; Henry Yuen

2013-06-23

423

V-band IMPATT power amplifier  

NASA Technical Reports Server (NTRS)

This program is the result of the continuing demand and future requirement for a high data rate 60-GHz communications link. A reliable solid-state transmitter which delivers the necessary power over a wide bandwidth using the present IMPATT diode technology required the development of combining techniques. The development of a 60-GHz IMPATT power combiner amplifier is detailed. The results form a basis from which future wideband, high-power IMPATT amplifiers may be developed. As a result, several state-of-the-art advancements in millimeter-wave components technology were achieved. Specific achievements for the amplifier integration were: development of a nonresonant divider/combiner circuit; reproducible multiple junction circulator assemblies; and reliable high power 60-GHz IMPATT diodes. The various design approaches and tradeoffs which lead to the final amplifier configuration are discussed. A detailed circuit design is presented for the various amplifier components, and the conical line combiner, radial line combiner, and circulator development are discussed. The performance of the amplifier, the overall achievement of the program, the implications of the results, and an assessment of future development needs and recommendations are examined.

Schell, S. W.

1985-01-01

424

Multiple excitation regenerative amplifier inertial confinement system  

DOEpatents

The invention relates to apparatus and methods for producing high intensity laser radiation generation which is achieved through an optical amplifier-storage ring design. One or two synchronized, counterpropagating laser pulses are injected into a regenerative amplifier cavity and amplified by gain media which are pumped repetitively by electrical or optical means. The gain media excitation pulses are tailored to efficiently amplify the laser pulses during each transit. After the laser pulses have been amplified to the desired intensity level, they are either switched out of the cavity by some switch means, as for example an electro-optical device, for any well known laser end uses, or a target means may be injected into the regenerative amplifier cavity in such a way as to intercept simultaneously the counterpropagating laser pulses. One such well known end uses to which this invention is intended is for production of high density and temperature plasmas suitable for generating neutrons, ions and x-rays and for studying matter heated by high intensity laser radiation.

George, Victor E. [Livermore, CA; Haas, Roger A. [Pleasanton, CA; Krupke, William F. [Pleasanton, CA; Schlitt, Leland G. [Livermore, CA

1980-05-27

425

Multiple excitation regenerative amplifier inertial confinement system  

DOEpatents

The invention relates to apparatus and methods for producing high intensity laser radiation generation which is achieved through an optical amplifier-storage ring design. One or two synchronized, counterpropagating laser pulses are injected into a regenerative amplifier cavity and amplified by gain media which are pumped repetitively by electrical or optical means. The gain media excitation pulses are tailored to efficiently amplify the laser pulses during each transit. After the laser pulses have been amplified to the desired intensity level, they are either switched out of the cavity by some switch means, as for example an electro-optical device, for any well known laser end uses, or a target means may be injected into the regenerative amplifier cavity in such a way as to intercept simultaneously the counterpropagating laser pulses. One such well known end uses to which this invention is intended is for production of high density and temperature plasmas suitable for generating neutrons, ions and x-rays and for studying matter heated by high intensity laser radiation. 11 figs.

George, V.E.; Haas, R.A.; Krupke, W.F.; Schlitt, L.G.

1980-05-27

426

Experimentally investigate the nonlinear amplifying process of high power picoseconds fiber amplifier  

NASA Astrophysics Data System (ADS)

The combination of laser amplification and nonlinear properties is the unique and special character of the fiber amplifier. In this paper, we power amplify picoseconds seed source with an all-fiber MOPA chain. The main purpose of this work is not to scale picoseconds laser power to an extremely high value but also to observe the nonlinear amplifying process within the high power picoseconds fiber amplifier. By altering the repetition rate of the seed pulse, corresponding to the peak power of the pulse, we compare the output properties of the high power picoseconds fiber amplifier. More than 50 W Raman-dominated broadband continuum has been demonstrated at a pulse repetition rate of 60 MHz. Anti-stokes spectral components and four wave mixing (FWM) are observed at a pulse repetition rate of 480 MHz. The output spectrum of picoseconds pulse is slightly broadened due to self-phase modulation (SPM) and yields as high as 71.3 W picoseconds laser output at a pulse repetition rate of ˜1 GHz. These results indicate that the fiber amplifier could be used not only as a conventional power amplifier but also as a nonlinear spectra convertor under some special condition. A potential application is that fiber amplifier could be directly utilized as a high power cladding pumped supercontinuum source using the nonlinear amplifying process within the active fiber.

Chen, Hongwei; Lei, Yu; Chen, Shengping; Hou, Jing; Lu, Qisheng

2013-04-01

427

Automatic alignment of double optical paths in excimer laser amplifier  

NASA Astrophysics Data System (ADS)

A kind of beam automatic alignment method used for double paths amplification in the electron pumped excimer laser system is demonstrated. In this way, the beams from the amplifiers can be transferred along the designated direction and accordingly irradiate on the target with high stabilization and accuracy. However, owing to nonexistence of natural alignment references in excimer laser amplifiers, two cross-hairs structure is used to align the beams. Here, one crosshair put into the input beam is regarded as the near-field reference while the other put into output beam is regarded as the far-field reference. The two cross-hairs are transmitted onto Charge Coupled Devices (CCD) by image-relaying structures separately. The errors between intersection points of two cross-talk images and centroid coordinates of actual beam are recorded automatically and sent to closed loop feedback control mechanism. Negative feedback keeps running until preset accuracy is reached. On the basis of above-mentioned design, the alignment optical path is built and the software is compiled, whereafter the experiment of double paths automatic alignment in electron pumped excimer laser amplifier is carried through. Meanwhile, the related influencing factors and the alignment precision are analyzed. Experimental results indicate that the alignment system can achieve the aiming direction of automatic aligning beams in short time. The analysis shows that the accuracy of alignment system is 0.63?rad and the beam maximum restoration error is 13.75?m. Furthermore, the bigger distance between the two cross-hairs, the higher precision of the system is. Therefore, the automatic alignment system has been used in angular multiplexing excimer Main Oscillation Power Amplification (MOPA) system and can satisfy the requirement of beam alignment precision on the whole.

Wang, Dahui; Zhao, Xueqing; Hua, Hengqi; Zhang, Yongsheng; Hu, Yun; Yi, Aiping; Zhao, Jun

2013-05-01

428

Multi-pass light amplifier  

NASA Technical Reports Server (NTRS)

A multiple-pass laser amplifier that uses optical focusing between subsequent passes through a single gain medium so that a reproducibly stable beam size is achieved within the gain region. A resonator or a White Cell cavity is provided, including two or more mirrors (planar or curvilinearly shaped) facing each other along a resonator axis and an optical gain medium positioned on a resonator axis between the mirrors or adjacent to one of the mirrors. In a first embodiment, two curvilinear mirrors, which may include adjacent lenses, are configured so that a light beam passing through the gain medium and incident on the first mirror is reflected by that mirror toward the second mirror in a direction approximately parallel to the resonator axis. A light beam translator, such as an optical flat of transparent material, is positioned to translate this light beam by a controllable amount toward or away from the resonator axis for each pass of the light beam through the translator. A second embodiment uses two curvilinear mirrors and one planar mirror, with a gain medium positioned in the optical path between each curvilinear mirror and the planar mirror. A third embodiment uses two curvilinear mirrors and two planar mirrors, with a gain medium positioned adjacent to a planar mirror. A fourth embodiment uses a curvilinear mirror and three planar mirrors, with a gain medium positioned adjacent to a planar mirror. A fourth embodiment uses four planar mirrors and a focusing lens system, with a gain medium positioned between the four mirrors. A fifth embodiment uses first and second planar mirrors, a focusing lens system and a third mirror that may be planar or curvilinear, with a gain medium positioned adjacent to the third mirror. A sixth embodiment uses two planar mirrors and a curvilinear mirror and a fourth mirror that may be planar or curvilinear, with a gain medium positioned adjacent to the fourth mirror. In a seventh embodiment, first and second mirrors face a third mirror, all curvilinear, in a White Cell configuration, and a gain medium is positioned adjacent to one of the mirrors.

Plaessmann, Henry (Inventor); Grossman, William M. (Inventor); Olson, Todd E. (Inventor)

1996-01-01

429

AIDA: A 16-channel amplifier ASIC to read out the advanced implantation detector array for experiments in nuclear decay spectroscopy  

SciTech Connect

We have designed a read-out ASIC for nuclear decay spectroscopy as part of the AIDA project - the Advanced Implantation Detector Array. AIDA will be installed in experiments at the Facility for Antiproton and Ion Research in GSI, Darmstadt. The AIDA ASIC will measure the signals when unstable nuclei are implanted into the detector, followed by the much smaller signals when the nuclei subsequently decay. Implant energies can be as high as 20 GeV; decay products need to be measured down to 25 keV within just a few microseconds of the initial implants. The ASIC uses two amplifiers per detector channel, one covering the 20 GeV dynamic range, the other selectable over a 20 MeV or 1 GeV range. The amplifiers are linked together by bypass transistors which are normally switched off. The arrival of a large signal causes saturation of the low-energy amplifier and a fluctuation of the input voltage, which activates the link to the high-energy amplifier. The bypass transistors switch on and the input charge is integrated by the high-energy amplifier. The signal is shaped and stored by a peak-hold, then read out on a multiplexed output. Control logic resets the amplifiers and bypass circuit, allowing the low-energy amplifier to measure the subsequent decay signal. We present simulations and test results, demonstrating the AIDA ASIC operation over a wide range of input signals. (authors)

Braga, D. [STFC Rutherford Appleton Laboratory, Didcot, OX11 0QX (United Kingdom); Coleman-Smith, P. J. [STFC Daresbury Laboratory, Warrington WA4 4AD (United Kingdom); Davinson, T. [Dept. of Physics and Astronomy, Univ. of Edinburgh, Edinburgh EH9 3JZ (United Kingdom); Lazarus, I. H. [STFC Daresbury Laboratory, Warrington WA4 4AD (United Kingdom); Page, R. D. [Dept. of Physics, Univ. of Liverpool, Oliver Lodge Laboratory, Liverpool L69 7ZE (United Kingdom); Thomas, S. [STFC Rutherford Appleton Laboratory, Didcot, OX11 0QX (United Kingdom)

2011-07-01

430

PASSIVE CONTROL OF FLUID POWERED HUMAN POWER AMPLIFIERS  

E-print Network

PASSIVE CONTROL OF FLUID POWERED HUMAN POWER AMPLIFIERS Perry Y. Li and Venkat Durbha Center is proposed for the control of fluid powered human power amplifiers. Human power amplifiers are mechanical tools that humans operate directly and the human force is amplified hydraulically or pneumatically

Li, Perry Y.

431

NEW CONCEPT OF A HYBRID AMPLIFIER FOR DRIVING PIEZOELECTRIC ACTUATORS  

Microsoft Academic Search

This paper describes a new concept of an amplifier for piezoelectric actuators, which combines the high efficiency of a switching amplifier with the output signal accuracy of an analogue amplifier. This so-called hybrid amplifier includes a bidirectional switching voltage source and an analogue final stage. The description of the control unit for the switching power supply with its unconventional structure

Christoph Stiebel; Hartmut Janocha

432

Wideband microwave\\/millimeter-wave solid-state amplifiers  

Microsoft Academic Search

Rapid strides have been made in recent years in the design and development of ultra-wideband solid-state amplifiers. A variety of design approaches based on GaAs FET and silicon bipolar technologies have been proposed. These include, among others, balanced amplifiers with couplers, reactive and resistive gain compensated circuits, feedback amplifiers, and traveling wave or distributed amplifiers . . . Panelists will

R. Pucel

1983-01-01

433

Enhanced photovoltaic performance utilizing effective charge transfers and light scattering effects by the combination of mesoporous, hollow 3D-ZnO along with 1D-ZnO in CdS quantum dot sensitized solar cells.  

PubMed

A combination of 3-dimensional (3D) hollow mesoporous ZnO microspheres (ZnO HMSP) and vertically grown one-dimensional ZnO nanowires (1D ZnO NWs) on a fluorine doped tin oxide (FTO) coated glass substrate has been investigated as a photoanode for a CdS quantum dot-sensitized solar cell (QSSC). A comparative study of the photovoltaic performance of the solar cell with devices fabricated with pristine ZnO HMSPs and ZnO NWs was carried out. The proposed photovoltaic device exhibits an enhancement in power conversion efficiency (PCE) upto ?74% and ?35%, as compared to the 1D ZnO NW and ZnO HMSP based solar cells. The maximum incident photon-to-current conversion efficiency (IPCE) for the solar cell was observed to be ?40%, whereas for the devices fabricated with bare ZnO HMSP and ZnO NW the IPCE were only ?32% and ?19%, respectively. The enhanced photovoltaic performance of the solar cell is attributed to the high Brunauer-Emmett-Teller (BET) surface area, efficient light-scattering effects and facilitated diffusion of the electrolyte for better functioning of the redox couple (S(2-)/Sn(2-)) in the hybrid photoanode. Moreover, a faster electron transport through 1D ZnO NWs provides better charge collection from the photoactive layer, which leads to an increase in the short circuit current density of the device. The present study highlights the design and development of a new hybrid photoanode for solar harvesting. PMID:24730023

Chetia, Tridip Ranjan; Barpuzary, Dipankar; Qureshi, Mohammad

2014-05-28

434

Charge control of electrostatically actuated micromechanical infrared Fabry-Pérot filters  

NASA Astrophysics Data System (ADS)

In this work, the applicability of charge controlled electrostatically tuneable optical filters is investigated. The filters are based on a Fabry-Pérot architecture, fabricated in a bulk micromachining process. Compared to surface micromachined devices, this design opens a path to higher optical performance due to the high planarity and low roughness of substrates but also introduces the drawback of acceleration sensitivity because of a moving mass. The common way of tuning those electrostatic actuators by applying constant voltages decreases the effective stiffness of the system and thus further increases this sensitivity for large deflections. In addition, the tuning range is limited to one third of the initial electrode spacing due to the pull-in effect. Therefore, designing voltage-controlled electrostatic actuators of such optical filters result in tough tradeoffs between initial electrode spacing, spring stiffness, supply voltage and chip area. In order to overcome the limitation of the tuning range and relax these tradeoffs, controlling the charge instead of voltage by using a switched capacitor amplifier is examined. Experiments have shown that it is possible to obtain a stable relative displacement of up to 60% limited by reflector tipping. Measuring gravity impact confirmed the expected reduced deflection dependency. Thus, it is possible to downsize the initial electrode spacing by 45% and the spring stiffness by 40% while achieving the same optical tuning range and acceleration sensitivity as in voltage mode. However, because of reflector tilting and the associated filter bandwidth degradation, a further tradeoff arises when using relative deflections greater 40 %.

Lehmann, Sebastian; Ebermann, Martin; Neumann, Norbert

2013-10-01

435

Novel non-chemically amplified (n-CARs) negative resists for EUVL  

NASA Astrophysics Data System (ADS)

We report the lithography performance of novel non chemical amplified (n-CARS) negative photoresist materials which are accomplished by homopolymers and copolymers that are prepared from monomers containing sulfonium groups. The latter have long been found to be sensitive to UV radiation and undergo polarity change on exposure. For this reason, these groups were chosen as radiation sensitive groups in non- CARs that are discussed herein. Novel n-CAR negative resists were synthesized and characterized for EUVL applications, as they are directly sensitive to radiation without utilizing the concept of chemical amplification. The n-CARs achieved 20 and 16 nm L/2S, L/S patterns to meet the ITRS requirements. We will also discuss the sensitivity and LER of these negative n-CARS to e-beam irradiation which will provide a basis for EUVL down to the 16 nm node and below. These new negative tone resist provide a viable path forward for designing non- chemically amplified resists that can obtain higher resolutions than current chemically amplified resists at competitive sensitivities.

Singh, Vikram; Satyanarayana, V. S. V.; Sharma, Satinder K.; Ghosh, Subrata; Gonsalves, Kenneth E.

2014-03-01

436

Amplification regimes of the orotron: A single-resonator amplifier  

NASA Astrophysics Data System (ADS)

A self-consistent, nonlinear model of orotron amplifiers is proposed for investigating single-stage and multistage amplifiers. The single-resonator amplifier is studied in detail including linear and nonlinear modes of amplification. A comparative study of both collective and single-electron interaction regimes is performed. The fundamentals which determine the level of amplifier performance are identified, and limiting output characteristics of the amplifier are determined. The theoretical results are compared with experimental data known to date.

Vavriv, D. M.; Schünemann, K.

1998-05-01

437

Design and implementation of low power multistage amplifiers and high frequency distributed amplifiers  

E-print Network

implemented in a 0.5??m CMOS process. Experimental results show that the SMC and SMFFC amplifiers achieve gain-bandwidth products of 4.6MHz and 9MHz, respectively, when driving a load of 25K?/120pF. Each amplifier operates from a ??1V supply, dissipates...

Mishra, Chinmaya

2005-11-01

438

Polymerization amplified detection for nanoparticle-based biosensing.  

PubMed

Efficient signal amplification processes are key to the design of sensitive assays for biomolecule detection. Here, we describe a new assay platform that takes advantage of both polymerization reactions and the aggregation of nanoparticles to amplify signal. In our design, a cascade is set up in which radicals generated by either enzymes or metal ions are polymerized to form polymers that can entangle multiple gold nanoparticles (AuNPs) into aggregates, resulting in a visible color change. Less than 0.05% monomer-to-polymer conversion is required to initiate aggregation, providing high sensitivity toward the radical generating species. Good sensitivity of this assay toward horseradish peroxidase, catalase, and parts per billion concentrations of iron and copper is shown. Incorporation of the oxygen-consuming enzyme glucose oxidase (GOx), enables this assay to be performed in open air conditions at ambient temperature. We anticipate that such a design will provide a useful platform for sensitive detection of a broad range of biomolecules through polymerization-based amplification. PMID:25315059

Gormley, Adam J; Chapman, Robert; Stevens, Molly M

2014-11-12

439

High power, high beam quality regenerative amplifier  

DOEpatents

A regenerative laser amplifier system generates high peak power and high energy per pulse output beams enabling generation of X-rays used in X-ray lithography for manufacturing integrated circuits. The laser amplifier includes a ring shaped optical path with a limited number of components including a polarizer, a passive 90 degree phase rotator, a plurality of mirrors, a relay telescope, and a gain medium, the components being placed close to the image plane of the relay telescope to reduce diffraction or phase perturbations in order to limit high peak intensity spiking. In the ring, the beam makes two passes through the gain medium for each transit of the optical path to increase the amplifier gain to loss ratio. A beam input into the ring makes two passes around the ring, is diverted into an SBS phase conjugator and proceeds out of the SBS phase conjugator back through the ring in an equal but opposite direction for two passes, further reducing phase perturbations. A master oscillator inputs the beam through an isolation cell (Faraday or Pockels) which transmits the beam into the ring without polarization rotation. The isolation cell rotates polarization only in beams proceeding out of the ring to direct the beams out of the amplifier. The diffraction limited quality of the input beam is preserved in the amplifier so that a high power output beam having nearly the same diffraction limited quality is produced.

Hackel, Lloyd A. (Livermore, CA); Dane, Clifford B. (Livermore, CA)

1993-01-01

440

Injection- Seeded Optoplasmonic Amplifier in the Visible  

PubMed Central

A hybrid optoplasmonic amplifier, injection-seeded by an internally-generated Raman signal and operating in the visible (563–675?nm), is proposed and evidence for amplification is presented. Comprising a gain medium tethered to a whispering gallery mode (WGM) resonator with a protein, and a plasmonic surface, the optical system described here selectively amplifies a single (or a few) Raman line(s) produced within the WGM resonator and is well-suited for routing narrowband optical power on-a-chip. Over the past five decades, optical oscillators and amplifiers have typically been based on the buildup of the field from the spontaneous emission background. Doing so limits the temporal coherence of the output, lengthens the time required for the optical field intensity to reach saturation, and often is responsible for complex, multiline spectra. In addition to the spectral control afforded by injection-locking, the effective Q of the amplifier can be specified by the bandwidth of the injected Raman signal. This characteristic contrasts with previous WGM-based lasers and amplifiers for which the Q is determined solely by the WGM resonator. PMID:25156810

Gartia, Manas Ranjan; Seo, Sujin; Kim, Junhwan; Chang, Te-Wei; Bahl, Gaurav; Lu, Meng; Liu, Gang Logan; Eden, J. Gary

2014-01-01

441

High power, high beam quality regenerative amplifier  

DOEpatents

A regenerative laser amplifier system generates high peak power and high energy per pulse output beams enabling generation of X-rays used in X-ray lithography for manufacturing integrated circuits. The laser amplifier includes a ring shaped optical path with a limited number of components including a polarizer, a passive 90 degree phase rotator, a plurality of mirrors, a relay telescope, and a gain medium, the components being placed close to the image plane of the relay telescope to reduce diffraction or phase perturbations in order to limit high peak intensity spiking. In the ring, the beam makes two passes through the gain medium for each transit of the optical path to increase the amplifier gain to loss ratio. A beam input into the ring makes two passes around the ring, is diverted into an SBS phase conjugator and proceeds out of the SBS phase conjugator back through the ring in an equal but opposite direction for two passes, further reducing phase perturbations. A master oscillator inputs the beam through an isolation cell (Faraday or Pockels) which transmits the beam into the ring without polarization rotation. The isolation cell rotates polarization only in beams proceeding out of the ring to direct the beams out of the amplifier. The diffraction limited quality of the input beam is preserved in the amplifier so that a high power output beam having nearly the same diffraction limited quality is produced.

Hackel, L.A.; Dane, C.B.

1993-08-24

442

Pulsed ti: sapphire laser power amplifier  

SciTech Connect

We have demonstrated an all solid state Ti:Sapphire laser system consisting of a power oscillator and single pass amplifier. The electrical-to-optical efficiency far exceeds that of the current CW systems. The pump lasers have lower capital and operating costs than the Argon-ion laser. In the future, we plan to scale the output power to higher levels by adding a fourth pump laser and improving the output power of the current pump lasers. Modeling results suggest that a large increase in efficiency can be realized by improving the beam quality of the pump lasers, even at the cost of reduced output power. We will explore this option by adding apertures to the cavity and/or reducing the rod diameter along with optimizing the resonator design. Other improvements in efficiency which will be investigated include double passing the amplifier for better extraction. To complete this work, the laser system will be converted into a two-stage amplifier. A narrow band, lower power oscillator currently under development will be injected in to the amplifier to study the extraction and efficiency characteristics of the amplifier throughout the tuning range of Ti:Sapphire. Detailed beam quality measurements will also be made. Other work will include doubling the narrow band output for materials processing applications.

Crozier, D W; Ault, Ault, E R; Erbert, G; Pierce, E L; Sleaford, B W

1999-02-23

443

Grains charges in interstellar clouds  

NASA Technical Reports Server (NTRS)

The charge of cosmic grains could play an important role in many astrophysical phenomena. It probably has an influence on the coagulation of grains and more generally on grain-grain collisions, and on interaction between charged particles and grains which could lead to the formation of large grains or large molecules. The electrostatic charge of grains depends mainly on the nature of constitutive material of the grain and on the physical properties of its environment: it results from a delicate balance between the plasma particle collection and the photoelectron emission, both of them depending on each other. The charge of the grain is obtained in two steps: (1) using the numerical model the characteristics of the environment of the grain are computed; (2) the charge of a grain which is embedded in this environment is determined. The profile of the equilibrium charge of some typical grains through different types of interstellar clouds is obtained as a function of the depth of the cloud. It is shown that the grain charge can reach high values not only in hot diffuse clouds, but also in clouds with higher densities. The results are very sensitive to the mean UV interstellar radiation field. Three parameters appear to be essential but with different levels of sensitivity of the charge: the gas density, the temperature, and the total thickness of the cloud.

Bel, N.; Lafon, J. P.; Viala, Y. P.

1989-01-01

444

Experimental studies of low-voltage, grating TWT amplifiers  

SciTech Connect

Recent results are presented from experimental studies of spontaneous emission and linear gain in a low-voltage, sheet-beam-compatible, grating TWT amplifier. A round probe beam from a 10 kV, 0.25 A Pierce gun electron source is utilized for 14 GHz amplifier experiments. From the spontaneous emission measurements the authors obtain the following valuable information: (a) measurements of the grating-induced spontaneous emission spectrum which can be correlated with the theoretically predicted linear gain curves, (b) measurements of broad-band noise emission which are critical for amplifier sensitivity characterization, and (c) measurements of spontaneous emission in the backward-wave regime to correlate with start oscillation predictions. The noise emission spectra have been correlated with the most dominant experimental factors including guide magnetic field intensity and body currents. Measurements of linear gain are also compared with the theoretical prediction in both forward and backward-wave regimes. The slow-wave structure consists of a uniform grating that adiabatically tapers to a smooth wall at both ends for impedance matching between the conventional TE{sub 10} rectangular guide mode and the TE{sub x10} hybrid slow-wave mode of the grating circuit. Small loop antennas are inserted at each end in smooth-walled rectangular guide sections for input and output signal coupling with the TE{sub 10} mode. Broadband, high-vacuum-compatible, SiC waveguide attenuator fins provide excellent suppression of unwanted end reflections and prevent the system from self-oscillation in the forward-wave regime.

Joe, J.; Basten, M.A.; Scharer, J.E.; Booske, J.H.; Wagner, K. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Electrical and Computer Engineering

1995-12-31

445

Charge Challenge  

NSDL National Science Digital Library

In this activity, learners explore how objects can have positive, negative, or neutral charges, which attract, repel and move between objects. Learners charge various materials and observe their interactions. Winter is an ideal time to perform these experiments (because there is less water vapor in the air); if it is humid, use a hair dryer to dry the objects, surfaces, and air around the work area.

2012-06-26

446

Phase noise of oscillators with unsaturated amplifiers  

NASA Astrophysics Data System (ADS)

We study the role of amplifier saturation in eliminating feedback noise in self-sustained oscillators. We extend previous works that use a saturated amplifier to quench fluctuations in the feedback magnitude, while simultaneously tuning the oscillator to an operating point at which the resonator nonlinearity cancels fluctuations in the feedback phase. We consider a generalized model which features an amplitude-dependent amplifier gain function. This allows us to determine the total oscillator phase noise in realistic configurations due to noise in both quadratures of the feedback, and to show that it is not necessary to drive the resonator to large oscillation amplitudes in order to eliminate noise in the phase of the feedback.

Kenig, Eyal; Cross, M. C.; Moehlis, Jeff; Wiesenfeld, Kurt

2013-12-01

447

Simulations of Surface Effects and Electron Emission from Diamond-Amplifier Cathodes  

SciTech Connect

Emission of electrons in diamond experiments based on the promising diamond-amplifier concept was recently demonstrated. Transmission mode experiments have shown the potential to realize over two orders of magnitude charge amplification. However, the recent emission experiments indicate that surface effects should be understood in detail to build cathodes with optimal properties. We have made progress in understanding secondary electron generation and charge transport in diamond with models we implemented in the VORPAL particle-in-cell computational framework. We introduce models that we have been implementing for surface effects (band bending and electron affinity), charge trapping, and electron emission from diamond. Then, we present results from 3D VORPAL diamond-vacuum simulations with the integrated capabilities on generating electrons and holes, initiated by energetic primary electrons, charge transport, and then emission of electrons from diamond into vacuum. Finally, we discuss simulation results on the dependence of the electron emission on diamond surface properties.

Dimitrov D. A.; Rao T.; Busby, R.; Smithe, D.; Cary, J.R.; Ben-Zvi, I.; Chang, X.; Smedley, J.; Wu, Q.; Wang, E.

2011-09-30

448

New family of non-chemically amplified resists  

NASA Astrophysics Data System (ADS)

Non-chemically amplified resists offer advantages over chemically-amplified (CA) resists because they are less susceptible to temperature variations and contaminants. In order for non-CA resists to be viable, they have to perform lithographically at an equivalent level with the CA resists from the point of view of quantum yield, resolution and etch resistance. We report here on new non-CA resists based on polymer esters that undergo deesterification to the corresponding acids upon exposure to UV, x-ray and e-beam radiation. The efficiency of the radiation reaction is surprisingly high. The resulting poly acids are base soluble and can be employed as positive working resists. The resists are composed of polymers and copolymers of methacrylate esters. The sensitivity of one derivative to x-ray is 75 mJ/cm2 and to e-beam is 1.0 (mu) C/cm2 at 10 KV. Best resolution obtained was 125 nm with x-ray radiation.

Aviram, Ari; Angelopoulos, Marie; Babich, Edward D.; Babich, Inna V.; Petrillo, Karen E.; Seeger, David E.

1998-06-01

449

Nondeterministic Amplifier for Two Photon Superpositions  

E-print Network

We examine heralded nondeterministic noiseless amplification based on the quantum scissors device, which has been shown to increase the one-photon amplitude of a state at the expense of the vacuum-state amplitude. Here we propose using the same basic design to perform perfect amplification in a basis set of up to two photons. The device is much more efficient than several one-photon amplifiers working in tandem. When used to amplify coherent states this advantage is shown using either fidelity or in terms of probability of sucessful action, or more strikingly in a combination of the two.

John Jeffers

2011-01-06

450

Transient dynamics of linear quantum amplifiers  

E-print Network

The transient dynamics of a quantum linear amplifier during the transition from damping to amplification regime is studied. The master equation for the quantized mode of the field is solved, and the solution is used to describe the statistics of the output field. The conditions under which a nonclassical input field may retain nonclassical features at the output of the amplifier are analyzed and compared to the results of earlier theories. As an application we give a dynamical description of the departure of the system from thermal equilibrium.

S. Maniscalco; J. Piilo; N. Vitanov; S. Stenholm

2006-01-13

451

Master-Oscillator/Power-Amplifier Laser System  

NASA Technical Reports Server (NTRS)

Master-oscillator/power-amplifier (MOPA) laser system operates in continuous-wave mode or in amplitude-modulation (e.g., pulse) mode by modulation of oscillator current. Power amplifier is laser-diode-pumped neodymium:yttrium lithium fluoride (Nd:YLF) laser; oscillator is laser diode. Offers relatively high efficiency and power. Because drive current to oscillator modulated, external electro-optical modulator not needed. Potential uses include free-space optical communications, coded laser ranging, and generation of high-power, mode-locked pulses.

Yu, Anthony W.; Krainak, Michael A.; Unger, Glenn L.

1994-01-01

452

High-energy regenerative thin disk amplifier  

NASA Astrophysics Data System (ADS)

Design of a compact regenerative laser amplifier based on two Yb:YAG thin-disks is presented. Energy up to 100 mJ in picoseconds pulses will be delivered with a repetition rate of 1 kHz. System is designed for seeding a kW-class multipass amplifier for industrial and scientific applications. Laser heads are pumped at zero-phonon line (968.825 nm [1]) by stabilized high-power pump diodes operated in pulsed regime. Seed pulses are produced in a fiber oscillator at 1030 nm and CPA technique utilizing transmission gratings for pulse stretching and compression is applied.

Chyla, Michal; Smrz, Martin; Mocek, Tomas

2012-07-01

453

Unique MMIC broadband power amplifier approach  

NASA Astrophysics Data System (ADS)

A broadband monolithic microwave integrated circuit (MMIC) power amplifier design approach is described using lossy matching networks in the form of a bridged-T all-pass network. This approach offers the advantage of exceptional gain flatness, good input voltage standing wave ratio (VSWR), high efficiency, and small size. A two-stage amplifier is described that delivers greater than 1 W across the 2 to 6 GHz range with a linear gain of 20 dB, an input VSWR better than 1.7:1, and a power-added efficiency of 30 to 37% with a chip area less than 4.4 sq mm.

Arell, Thomas; Hongsmatip, Thongchai

1993-10-01

454

Noise figure of amplified dispersive Fourier transformation  

SciTech Connect

Amplified dispersive Fourier transformation (ADFT) is a powerful tool for fast real-time spectroscopy as it overcomes the limitations of traditional optical spectrometers. ADFT maps the spectrum of an optical pulse into a temporal waveform using group-velocity dispersion and simultaneously amplifies it in the optical domain. It greatly simplifies spectroscopy by replacing the diffraction grating and detector array in the conventional spectrometer with a dispersive fiber and single-pixel photodetector, enabling ultrafast real-time spectroscopic measurements. Following our earlier work on the theory of ADFT, here we study the effect of noise on ADFT. We derive the noise figure of ADFT and discuss its dependence on various parameters.

Goda, Keisuke; Jalali, Bahram [Electrical Engineering Department, University of California, Los Angeles, California 90095 (United States)

2010-09-15

455

Multi-pass amplifier architecture for high power laser systems  

DOEpatents

A main amplifier system includes a first reflector operable to receive input light through a first aperture and direct the input light along an optical path. The input light is characterized by a first polarization. The main amplifier system also includes a first polarizer operable to reflect light characterized by the first polarization state. The main amplifier system further includes a first and second set of amplifier modules. Each of the first and second set of amplifier modules includes an entrance window, a quarter wave plate, a plurality of amplifier slablets arrayed substantially parallel to each other, and an exit window. The main amplifier system additionally includes a set of mirrors operable to reflect light exiting the first set of amplifier modules to enter the second set of amplifier modules and a second polarizer operable to reflect light characterized by a second polarization state.

Manes, Kenneth R; Spaeth, Mary L; Erlandson, Alvin C

2014-04-01

456

Role of electrolytes on charge recombination in dye-sensitized TiO(2) solar cell (1): the case of solar cells using the I(-)/I(3)(-) redox couple.  

PubMed

Performance of dye-sensitized solar cells (DSCs) was investigated depending on the compositions of the electrolyte, i.e., the electrolyte with a different cation such as Li(+), tetra-n-butylammonium (TBA(+)), or 1,2-dimethyl-3-propylimidazolium (DMPIm(+)) in various concentrations, with and without 4-tert-butylpyridine (tBP), and with various concentrations of the I(-)/I(3)(-) redox couple. Current-voltage characteristics, electron lifetime, and electron diffusion coefficient were measured to clarify the effects of the constituents in the electrolyte on the charge recombination kinetics in the DSCs. Shorter lifetimes were found for the DSCs employing adsorptive cations of Li(+) and DMPIm(+) than for a less-adsorptive cation of TBA(+). On the other hand, the lifetimes were not influenced by the concentrations of the cations in the solutions. Under light irradiation, open-circuit voltages of DSCs decreased in the order of TBA(+)> DMPIm(+) > Li(+), and also decreased with the increase of [Li(+)]. The decreases of open-circuit voltage (V(oc)) were attributed to the positive shift of the TiO(2) conduction band potential (CBP) by the surface adsorption of DMPIm(+) and Li(+). These results suggest that the difference of the free energies between that of the electrons in the TiO(2) and of I(3)(-) has little influence on the electron lifetimes in the DSCs. The shorter lifetime with the adsorptive cations was interpreted with the thickness of the electrical double layer formed by the cations, and the concentration of I(3)(-) in the layer, i.e., TBA(+) formed thicker double layer resulting in lower concentration of I(3)(-) on the surface of the TiO(2). The addition of 4-tert-butylpyridine (tBP) in the presence of Li(+) or TBA(+) showed no significant influence on the lifetime. The increase of V(oc) by the addition of tBP into the electrolyte containing Li(+) and the I(-)/I(3)(-) redox couple was mainly attributed to the shift of the CBP back to the negative potential by reducing the amount of adsorbed Li cations. PMID:16851382

Nakade, Shogo; Kanzaki, Taisuke; Kubo, Wataru; Kitamura, Takayuki; Wada, Yuji; Yanagida, Shozo

2005-03-01

457

Charge without charge in quarks  

E-print Network

With appropriate gauge transformations, field can replace electric charge in quarks. Classical quarks, in a necessary non-gauge invariant formulation, are used for illustration, bringing to the fore the lim- itations of the usual electric charge densities for single particles in Coulomb equations. The results are encouraging; the solutions for the Coulomb potentials apply individually to each quark in a shell struc- ture. A remarkably simple relation emerges between the Coulomb and weak potentials.

Harry Schiff

2013-08-06

458

Characterization and optimization of the magnetron directional amplifier  

NASA Astrophysics Data System (ADS)

Many applications of microwave wireless power transmission (WPT) are dependent upon a high-powered electronically-steerable phased array composed of many radiating modules. The phase output from the high-gain amplifier in each module must be accurately controlled if the beam is to be properly steered. A highly reliable, rugged, and inexpensive design is essential for making WPT applications practical. A conventional microwave oven magnetron may be combined with a ferrite circulator and other external circuitry to create such a system. By converting it into a two-port amplifier, the magnetron is capable of delivering at least 30 dB of power gain while remaining phase-locked to the input signal over a wide frequency range. The use of the magnetron in this manner is referred to as a MDA (Magnetron Directional Amplifier). The MDA may be integrated with an inexpensive slotted waveguide array (SWA) antenna to form the Electronically-Steerable Phased Array Module (ESPAM). The ESPAM provides a building block approach to creating phased arrays for WPT. The size and shape of the phased array may be tailored to satisfy a diverse range of applications. This study provided an in depth examination into the capabilities of the MDA/ESPAM. The basic behavior of the MDA was already understood, as well as its potential applicability to WPT. The primary objective of this effort was to quantify how well the MDA could perform in this capacity. Subordinate tasks included characterizing the MDA behavior in terms of its system inputs, optimizing its performance, performing sensitivity analyses, and identifying operating limitations. A secondary portion of this study examined the suitability of the ESPAM in satisfying system requirements for the solar power satellite (SPS). Supporting tasks included an analysis of SPS requirements, modeling of the SWA antenna, and the demonstration of a simplified phased array constructed of ESPAM elements. The MDA/ESPAM is well suited for use as an amplifier or an element in a WPT phased array, providing over 75% efficiency and a fractional bandwidth exceeding 1.7% at 2.45 GHz. The results of this effort provide the WPT design engineer with tools to predict the MDA's optimum performance and limitations.

Hatfield, Michael Craig

459

Fluidity dependence of deprotonation kinetics of chemically amplified resist  

NASA Astrophysics Data System (ADS)

Chemically amplified resists have been widely used in the mass production line. An acid generation mechanism induced by ionizing radiation with extreme ultraviolet (EUV) and electron beam is an important issue for improvement of the resist performance such as sensitivity, roughness, and resolution below 16 nm. However, the details of deprotonation kinetics from the ionized resist solid film immediately after the ionization have been still unclear. In this study, pulse radiolysis of highly concentrated poly(4-hydroxystylene) (PHS) solutions was performed. The viscosity dependence on the deprotonation dynamics of the ionized concentrated solutions was investigated to clarify the proton generation of ionized PHS in a medium with low mobility. The deprotonation from the PHS radical cation becomes slower with increasing PHS concentration. It is suggested that the deprotonation reaction is slower in a less mobile medium because of decrease of the molecular motions.

Okamoto, Kazumasa; Ishida, Takuya; Yamamoto, Hiroki; Kozawa, Takahiro; Fujiyoshi, Ryoko; Umegaki, Kikuo

2014-03-01

460

A three-terminal semiconductor-superconductor transimpedance amplifier  

NASA Astrophysics Data System (ADS)

The authors report an improved hybrid three-terminal transimpedance amplifier (TIA) with significant current gain. The TIA consists of a semiconductor diode configured for injection of electrons into a thin base electrode superconductor-insulator-superconductor junction, whose response is read out by low-impedance superconductive electronics. An input dynamic impedance greater than 10 exp 11 ohms, an output dynamic impedance of approximately 10 exp -3 ohm, a current gain of 20, and an effective input noise current less than 10 exp -14 A/sq rt Hz were achieved. The TIA was operated in a sensor test bed with an extrinsic silicon infrared (IR) detector and superconductive analog-to-digital (A/D) converter. This device permits matching state-of-the-art semiconductor IR detectors with superconductive A/D converters, enabling a fully digital cryogenic focal plane array sensor with high sensitivity and speed but reduced power consumption.

Pham, T.; Leung, M.; Dalrymple, B.; Abelson, L.; Spargo, J.; Ou, S.; Chan, H.; Silver, A.

1993-03-01

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