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Tiantian Sun - One of the best experts on this subject based on the ideXlab platform.

  • a comparison using faraday cups with 1013 ω amplifiers and a secondary electron multiplier to measure os isotopes by negative thermal ionization mass spectrometry
    Rapid Communications in Mass Spectrometry, 2017
    Co-Authors: Guiqin Wang, Tiantian Sun
    Abstract:

    RATIONALE According to the Johnson-Nyquist noise equation, the Value of electron noise is proportional to the square root of the Resistor Value. This relationship gives a theoretical improvement of 100 in the signal/noise ratio by going from 1011 Ω to 1013 Ω amplifiers for Faraday detection in thermal ionization mass spectrometry (TIMS). METHODS We measured Os isotopes using static Faraday cups with 1013 Ω amplifiers in negative thermal ionization mass spectrometry (NTIMS) and compared the results with those obtained with 1011 Ω amplifiers and by peak-hopping on a single secondary electron multiplier (SEM). We analysed large loads of Os (1 μg) at a range of intensities of 187 OsO3 (0.02-10 mV) in addition to small loads of Os (5-500 pg) to compare the results of the three methods. RESULTS Using 1013 Ω amplifiers, the long-term reproducibility determined from Merck Os was 187 Os/188 Os = 0.1211 ± 0.0086 and 0.120229 ± 0.000034 at 0.02 mV and 10 mV of 187 OsO3 intensities. Meanwhile, the analysed JMC Os loadings of 5 and 500 pg showed 187 Os/188 Os = 0.10669 ± 0.00036 and 0.106807 ± 0.000023. In comparison, the Values measured by the SEM were 187 Os/188 Os = 0.10704 ± 0.00056 and 0.10690 ± 0.00013. All errors are in 2 standard deviation (SD). CONCLUSIONS Both the accuracy and the precision determined using the 1013 Ω amplifiers and the SEM are identical when the Os amounts are within 10-50 pg. However, the former analysis time can be shortened by approximately two-thirds. The SEM measurement is still the most precise method for Os amounts 50 pg.

Guiqin Wang - One of the best experts on this subject based on the ideXlab platform.

  • a comparison using faraday cups with 1013 ω amplifiers and a secondary electron multiplier to measure os isotopes by negative thermal ionization mass spectrometry
    Rapid Communications in Mass Spectrometry, 2017
    Co-Authors: Guiqin Wang, Tiantian Sun
    Abstract:

    RATIONALE According to the Johnson-Nyquist noise equation, the Value of electron noise is proportional to the square root of the Resistor Value. This relationship gives a theoretical improvement of 100 in the signal/noise ratio by going from 1011 Ω to 1013 Ω amplifiers for Faraday detection in thermal ionization mass spectrometry (TIMS). METHODS We measured Os isotopes using static Faraday cups with 1013 Ω amplifiers in negative thermal ionization mass spectrometry (NTIMS) and compared the results with those obtained with 1011 Ω amplifiers and by peak-hopping on a single secondary electron multiplier (SEM). We analysed large loads of Os (1 μg) at a range of intensities of 187 OsO3 (0.02-10 mV) in addition to small loads of Os (5-500 pg) to compare the results of the three methods. RESULTS Using 1013 Ω amplifiers, the long-term reproducibility determined from Merck Os was 187 Os/188 Os = 0.1211 ± 0.0086 and 0.120229 ± 0.000034 at 0.02 mV and 10 mV of 187 OsO3 intensities. Meanwhile, the analysed JMC Os loadings of 5 and 500 pg showed 187 Os/188 Os = 0.10669 ± 0.00036 and 0.106807 ± 0.000023. In comparison, the Values measured by the SEM were 187 Os/188 Os = 0.10704 ± 0.00056 and 0.10690 ± 0.00013. All errors are in 2 standard deviation (SD). CONCLUSIONS Both the accuracy and the precision determined using the 1013 Ω amplifiers and the SEM are identical when the Os amounts are within 10-50 pg. However, the former analysis time can be shortened by approximately two-thirds. The SEM measurement is still the most precise method for Os amounts 50 pg.

Laszlo B. Kish - One of the best experts on this subject based on the ideXlab platform.

  • ENHANCED SECURE KEY EXCHANGE SYSTEMS BASED ON THE JOHNSON- NOISE SCHEME
    Metrology and Measurement Systems, 2013
    Co-Authors: Laszlo B. Kish
    Abstract:

    We introduce seven new versions of the Kirchhoff -Law-Johnson-(like)-Noise (KLJN) classical physical secure key exchange scheme and a new transient protocol for practically -perfect security. While these practical improvements offer progressively enhanced security and/or speed for non-ideal conditions, the fundamental physical laws providing the security remain the same. In the "intelligent" KLJN (iKLJN) scheme, Alice and Bob utilize the fact that they exactly know not only their own Resistor Value but also the stochastic time function of their own noise, which they generate before feeding it into the loop. By using this extra information, they can reduce the duration of exchanging a single bit and in this way they achieve not only higher speed but also an enhanced security because Eve's information will significantly be reduced due to smaller statistics. In the "multiple" KLJN (MKLJN) system, Alice and Bob have publicly known identical sets of different Resistors with a proper, publicly known truth table about the bit-interpretation of their combination. In this new situation, for Eve to succeed, it is not enough to find out which end has the higher Resistor. Eve must exactly identify the actual Resistor Values at both sides. In the "keyed" KLJN (KKLJN) system, by using secure communication with a formerly shared key, Alice and Bob share a proper time -dependent truth table for the bit-interpretation of the Resistor situation for each secure bit exchange step during generating the next key. In this new situation, for Eve to succeed, it is not enough to find out the Resistor Values at the two ends. Eve must also know the former key. The remaining four KLJN schemes are the combinations of the above protocols to synergically enhance the security properties. The se are: the "intelligent-multiple" (iMKLJN), the "intelligent-keyed" (iKKLJN), the "keyed -multiple" (KMKLJN) and the "intelligent-keyed-multiple" (iKMKLJN) KLJN key exchange systems. Finally, we introduce a new transient -protocol offering practically-perfe ct security without privacy amplification, which is not needed in practical applications but it is shown for the sake of ongoing discussions.

  • Enhanced Secure Key Exchange Systems Based on the Johnson-Noise Scheme
    viXra, 2013
    Co-Authors: Laszlo B. Kish
    Abstract:

    We introduce seven new versions of the Kirchhoff-Law-Johnson-(like)-Noise (KLJN) classical physical secure key exchange scheme and a new transient protocol for practically-perfect security. While these practical improvements offer progressively enhanced security and/or speed for the non-ideal conditions, the fundamental physical laws providing the security remain the same. In the "intelligent" KLJN (iKLJN) scheme, Alice and Bob utilize the fact that they exactly know not only their own Resistor Value but also the stochastic time function of their own noise, which they generate before feeding it into the loop. By using this extra information, they can reduce the duration of exchanging a single bit and in this way they achieve not only higher speed but also an enhanced security because Eve's information will significantly be reduced due to smaller statistics. In the "multiple" KLJN (MKLJN) system, Alice and Bob have publicly known identical sets of different Resistors with a proper, publicly known truth table about the bit-interpretation of their combination. In this new situation, for Eve to succeed, it is not enough to find out which end has the higher Resistor. Eve must exactly identify the actual Resistor Values at both sides. In the "keyed" KLJN (KKLJN) system, by using secure communication with a formerly shared key, Alice and Bob share a proper time-dependent truth table for the bit-interpretation of the Resistor situation for each secure bit exchange step during generating the next key. In this new situation, for Eve to succeed, it is not enough to find out the Resistor Values at the two ends. Eve must also know the former key. The remaining four KLJN schemes are the combinations of the above protocols to synergically enhance the security properties. These are: the "intelligent-multiple" (iMKLJN), the "intelligent-keyed" (iKKLJN), the "keyed-multiple" (KMKLJN) and the "intelligent-keyed-multiple" (iKMKLJN) KLJN key exchange systems. Finally, we introduce a new transient-protocol offering practically-perfect security without privacy amplification, which is not needed at practical applications but it is shown for the sake of ongoing discussions.

James Njuguna - One of the best experts on this subject based on the ideXlab platform.

  • analyses of power output of piezoelectric energy harvesting devices directly connected to a load Resistor using a coupled piezoelectric circuit finite element method
    IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2009
    Co-Authors: Emma Worthington, James Njuguna
    Abstract:

    This paper presents, for the first time, a coupled piezoelectric-circuit finite element model (CPC-FEM) to analyze the power output of a vibration-based piezoelectric energy-harvesting device (EHD) when it is connected to a load Resistor. Special focus is given to the effect of the load Resistor Value on the vibrational amplitude of the piezoelectric EHD, and thus on the current, voltage, and power generated by the device, which are normally assumed to be independent of the load Resistor Value to reduce the complexity of modeling and simulation. The presented CPC-FEM uses a cantilever with a sandwich structure and a seismic mass attached to the tip to study the following characteristics of the EHD as a result of changing the load Resistor Value: 1) the electric outputs: the current through and voltage across the load Resistor; 2) the power dissipated by the load Resistor; 3) the displacement amplitude of the tip of the cantilever; and 4) the shift in the resonant frequency of the device. It is found that these characteristics of the EHD have a significant dependence on the load Resistor Value, rather than being independent of it as is assumed in most literature. The CPC-FEM is capable of predicting the generated output power of the EHD with different load Resistor Values while simultaneously calculating the effect of the load Resistor Value on the displacement amplitude of the tip of the cantilever. This makes the CPC-FEM invaluable for validating the performance of a designed EHD before it is fabricated and tested, thereby reducing the recurring costs associated with repeat fabrication and trials. In addition, the proposed CPC-FEM can also be used for producing an optimized design for maximum power output.

  • Coupled piezoelectric-circuit FEA to study influence of a resistive load on power output of piezoelectric energy devices
    Smart Sensors Actuators and MEMS IV, 2009
    Co-Authors: Meiling Zhu, Emma Worthington, James Njuguna
    Abstract:

    This paper presents, for the first time, a coupled piezoelectric-circuit finite element model (CPC-FEM) to analyze the power output of vibration-based piezoelectric energy harvesting devices (EHDs) when connected to a resistive load. Special focus is given to the effect of the resistive load Value on the vibrational amplitude of the piezoelectric EHDs, and thus on the current, voltage, and power generated by the EHDs, which are normally assumed to be independent of the resistive load in order to reduce the complexity of modelling and simulation. The CPC-FEM presented uses a cantilever with the sandwich structure and a seismic mass attached to the tip to study the following load characteristics of the EHD as a result of changing the load Resistor Value: (1) the electric outputs of the EHD: current and voltage, (2) the power dissipated by the resistive load, (3) the vibration amplitude of tip displacement, and (4) the shift in resonant frequency of the cantilever. Significant dependences of the characteristics of the piezoelectric EHDs on the externally connected resistive load are found, rather than independency, as previously assumed in most literature. The CPC-FEM is capable of predicting the generated power output with different resistive load Values while simultaneously considering the effect of the Resistor Value on the vibration amplitude. The CPC-FEM is invaluable for validating the performance of a device before fabrication and testing, thereby reducing the recurring costs associated with repeat fabrication and trials, and also for optimizing device design for maximal power-output generation.

Xu Jifeng - One of the best experts on this subject based on the ideXlab platform.

  • A comparison using Faraday cups with 10(13) amplifiers and a secondary electron multiplier to measure Os isotopes by negative thermal ionization mass spectrometry
    'Wiley', 2017
    Co-Authors: Wang Guiqin, Sun Tiantian, Xu Jifeng
    Abstract:

    RationaleAccording to the Johnson-Nyquist noise equation, the Value of electron noise is proportional to the square root of the Resistor Value. This relationship gives a theoretical improvement of 100 in the signal/noise ratio by going from 10(11) to 10(13) amplifiers for Faraday detection in thermal ionization mass spectrometry (TIMS). MethodsWe measured Os isotopes using static Faraday cups with 10(13) amplifiers in negative thermal ionization mass spectrometry (NTIMS) and compared the results with those obtained with 10(11) amplifiers and by peak-hopping on a single secondary electron multiplier (SEM). We analysed large loads of Os (1 g) at a range of intensities of (OsO3)-Os-187 (0.02-10 mV) in addition to small loads of Os (5-500 pg) to compare the results of the three methods. ResultsUsing 10(13) amplifiers, the long-term reproducibility determined from Merck Os was Os-187/Os-188 = 0.1211 0.0086 and 0.120229 +/- 0.000034 at 0.02 mV and 10 mV of (OsO3)-Os-187 intensities. Meanwhile, the analysed JMC Os loadings of 5 and 500 pg showed Os-187/Os-188 = 0.10669 +/- 0.00036 and 0.106807 +/- 0.000023. In comparison, the Values measured by the SEM were Os-187/Os-188 = 0.10704 +/- 0.00056 and 0.10690 +/- 0.00013. All errors are in 2 standard deviation (SD). ConclusionsBoth the accuracy and the precision determined using the 10(13) amplifiers and the SEM are identical when the Os amounts are within 10-50 pg. However, the former analysis time can be shortened by approximately two-thirds. The SEM measurement is still the most precise method for Os amounts 50 pg