Pierce Theory Research Articles

ANALISIS SEMIOTIKA DAN PESAN SOSIAL PADA IKLAN COCA-COLA VERSI AVATAR

The focus of the study is the Semiotic Analysis of the Coca-Cola Ad Avatar version of a hidden message about social concern about the impact of technological developments that have transformed society into anti-social. To support this research the author uses the theory of Charles Sander Pierce which classifies the type of sign based on objects into three types, namely icon, index and symbol. With Pierce's theory the significance of the signs contained in the Coca-Cola Avatar Version ads will be analyzed.
 The type of research used is descriptive qualitative research with semiology communication approach. The data of this research is qualitative data so that the data is substansif category which then interpreted with reference of scientific references.
 Coca-Cola Company also wants to convey the information that in this era of globalization / millenial era, many social concepts, such as integration, unity, nationalism and solidarity, seem to be losing their social reality owing to the excessive use of technological devices. The various social realities that develop on a global scale, especially as a result of advances in information technology, leads to social end.
 
 
 Key Word : Advertisement, Coca-Cola, Avatar, hyperreality

Integrated Planar Three-Beam Electron Optics System for 220-GHz Folded Waveguide TWT

An integrated planar three-beam electron optics system is designed for our 220-GHz cascaded folded waveguide TWT. First, a planar three-beam gun is designed based on Pierce theory and Vaughan’s synthesis method with simplification of the focus electrode and the anode to facilitate manufacture and assembly, which is characteristic with 20 kV, ${3} \times {0.1}$ A, and beam radius of 0.1 mm. Simulation results show that the gun model performs well. Next, a uniform magnetic focusing structure used for constraining the three-beam array with adjacent beam separation of 8 mm is designed. Magnetic saturation analysis of the pole piece and structure parameters optimization of the magnets is considered thoroughly, which may guarantee the transport stability of the three-beam array and keep down the volume of the magnet. Simulation results show that the transmission of three-beam array up to 18 mm is 100% with the maximum ripple of 11.2% in the designed focusing structure. And the integrated planar three-beam electron optics system is verified as a stable system with the beam characteristics analyses of matching error, beam voltage fluctuation, and variation of peak ${B}_{z}$ .

Amy Pierce, Language Acquisition and Syntactic Theory: A Comparative Analysis of French and English Child Grammars, Kluwer Academic Publishers, 1992, xi+173 pp.

Amy Pierce, Language Acquisition and Syntactic Theory: A Comparative Analysis of French and English Child Grammars, Kluwer Academic Publishers, 1992, xi+173 pp.

On the evaluation of Pierce parameters C and Q in a traveling wave tube

A study of an exactly solvable model of a traveling wave tube (TWT) shows that Pierce gain parameter C and space charge parameter Q generally depend on wavenumber k in addition to frequency ω. The choice of k at which C and Q are evaluated may strongly affect their values and, consequently, the values of the small signal gain obtained from 3- and 4-wave Pierce theory. In order to illustrate this effect, we calculate the spatial amplification rate, ki, from the exact dispersion relation for a dielectric TWT model which is exactly solvable. We compare this exact value of ki with approximate values obtained from Pierce's classical 3-wave and 4-wave dispersion relations, obtained by making various assumptions on k in the evaluation of C and Q. We find that the various ways to approximate C and Q will have a significant influence on the numerical values of ki. For our dielectric TWT example, Pierce's 4-wave TWT dispersion relation generally yields the most accurate values of ki if Q is evaluated for k = ω/v0, where v0 is the beam velocity, and if the complete frequency and wavelength dependence of C is retained. Pierce's 3-wave theory also yields accurate values of ki using a different form of Q from the 4-wave theory. The implications of this result for TWT design are explored.

Gain analysis of the gap-groove folded-waveguide travelling-wave tube

In this paper, a Pierce-type analysis for the novel gap-groove folded-waveguide (GGFW) sheet electron beam traveling-wave tube is presented. The introduced analysis effectively reduces the required time for the initial design and optimization procedure of these kinds of tubes. Using equivalent circuit of the slow-wave structure, the one-dimensional linearized Pierce theory is applied to calculate the amplifier gain. Furthermore, the obtained results of the analysis are compared with those of PIC simulations. Good agreement between these results verifies the correctness and accuracy of the presented analysis.

An Extended Theoretical Method Used for Design of Sheet Beam Electron Gun

An extended theoretical method based on Pierce theory is investigated in this paper to provide a reliably support and direct approaches for the design of the general sheet beam electron gun. First, the general characteristics of the sheet beam electron gun are discussed by dividing the gun into three investigation parts, and the design curves are derived theoretically, which are quite different from the curves for circular beam gun. The valid range of curvature radius ratio of cathode to anode R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> /R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a</sub> for sheet beam gun is achieved as 1.879 <; R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> /R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a</sub> <; 2.79 with the compression factor M of 1.879 <; M <; 30, which can make the sheet beam gun more stable and reliable. Then, the theoretical design method based on the design curves for sheet beam gun is deduced, and the reconstruction of anode aperture and the correction of cylindrical aberration are considered thoroughly, which may improve the design method more accurate and practical. Based on the theoretical calculation and parameters analysis, two types of sheet beam gun models with different M of 4 and 10 are constructed and simulated by the 3-D software, respectively, with the same beam voltage of 22 kV, a beam current of 3.50 A, and the beam cross section of 6 mm×0.24 mm. The results achieve the good agreement and verification with the theoretical expectation for the both the two sheet beam gun.

Low Starting Electron Beam Current in Degenerate Band Edge Oscillators

We propose a new principle of operation in vacuum electron-beam-based oscillators that leads to a low beam current for starting oscillations. The principle is based on super synchronous operation of an electron beam interacting with four degenerate electromagnetic modes in a slow-wave structure (SWS). The four mode super synchronous regime is associated with a very special degeneracy condition in the dispersion diagram of a cold periodic SWS called degenerate band edge (DBE). This regime features a giant group delay in the finitelength SWS and low starting-oscillation beam current. The starting beam current is at least an order of magnitude smaller compared to a conventional backward wave oscillator (BWO) of the same length. As a representative example we consider a SWS conceived by a periodically-loaded metallic waveguide supporting a DBE, and investigate starting-oscillation conditions using Pierce theory generalized to coupled transmission lines (CTL). The proposed super synchronism regime can be straightforwardly adapted to waveguide geometries others than the periodically-loaded waveguide considered here since DBE is a general property that can be realized in a variety of structures.

Five-Wave Equation for Small-Signal Analysis of Traveling-Wave Tubes Considering the Effects of Axial Periodicity of the Interaction Structure

The conventional Pierce theory is used to analyze traveling-wave tube (TWT) amplifiers. This theory is a convenient method to design helix TWTs. However, in some cases such as coupled-cavity TWTs and folded-waveguide TWTs, this approach yields nonphysical results. In fact, backward-wave excitation may not be ignored for high-power wideband coupled cavities as well as for devices operating near the band edges. The Pierce-type equation is modified to include both backward and forward RF waves simultaneously. A fifth-order algebraic equation is derived that yields TWT small-signal gain in approximately the entire frequency band, including near cutoff frequencies. This approach is based on the coupling between two fast and slow space-charge waves and three RF space-harmonic waves, using independent space-harmonic approximation. The obtained equation may be used to analyze the coupled-cavity folded waveguide and ladder TWT structures.

Simplified analytical model for sound level prediction at shielded urban locations involving multiple diffraction and reflections

Accurate and efficient prediction of the sound field in shadow zones behind obstacles is a challenging task but essential to produce urban noise maps. A simplified method is presented to predict sound levels at shielded urban locations, including multi-edge diffraction over successive buildings and multiple reflections between parallel façades. The model is essentially based on Pierce's diffraction theory, where the Fresnel Integral is approximated by trigonometric functions for efficient evaluation, and parameterized for urban environments. The model has been validated for idealized urban configurations by comparing to the results of Pierce's theory and a full-wave numerical method. In case of multi-edge diffraction over buildings in absence of a source or receiver canyon, deviations from the full-wave simulations are smaller than 2 dB for the octave bands with central frequencies ranging from 125 to 1000 Hz. However, larger errors are made when receivers are close to the extension line from the diffraction edge closest to the receiver. In case of combining the simplified multi-edge diffraction model with an efficient approach for including the series of mirror sources and mirror receivers, based on the Hurwitz-Lerch transcendent, this same accuracy is obtained.

Pierce gain analysis for sheet-beam multiple-circuits traveling-wave amplifiers

A pierce type analysis for multiple-circuits sheet-beam traveling wave amplifiers is presented. The introduced analysis effectively reduces the required time for the initial design and optimization procedure of these kinds of tubes. The one-dimensional linearized Pierce theory is extended to multiple circuits coupled to the sheet beam using equivalent circuit of slow-wave structures as well as dividing the sheet beam into many discrete beams, and then, the amplifier gain is calculated. Furthermore, this analysis is used to calculate the gain of two sheet-beam TWTs with single and double slow-wave structures, and the results are compared with those of particle-in-cell simulations. Good agreement between these results verifies the correctness and accuracy of the presented analysis.

Linear Analysis of Helix Traveling-Wave Tubes With Nonnegligible Space Charge Using the Improved Helical-Harmonics Approximation

Linear dispersion relation of helix traveling-wave tubes (TWTs) is obtained and numerically solved using the improved helical-harmonics approximation (HHA), which has been recently presented for modeling helix thickness. The presented technique allows simultaneous examination of effects of various parameters, such as helix tape thickness, nonuniform beam current density profile, potential depression across the beam, finite axial magnetic field, and rod shape, on the tube's small-signal characteristics. It is shown that while the results obtained from the 1-D Pierce theory agree well with those obtained from the field theory in the low-space-charge regime, they show major deviation in the nonresonant and high-space-charge regime. It is also shown that the small-signal gain and phase results obtained by means of the improved HHA agree well with those obtained from the tape-helix model and also the conventional HHA whenever the relevant cold dispersion characteristics are in a reasonable agreement.

The effect of a space charge on amplification in traveling-wave tubes with periodic slow-wave systems

The effect of a space charge on solutions to the previously obtained universal characteristic equations and, accordingly, on amplification in traveling-wave tubes (TWTs) with periodic slow-wave structures (SWSs) is considered. The peculiarities of electron waves differing from the predictions of the Pierce theory, which is valid only for TWTs with smooth SWSs, are reported.

Extension of the Pierce Model to Multiple Transmission Lines Interacting With an Electron Beam

A possible route toward achieving high-power microwave (HPM) devices is through the use of novel slow-wave structures, represented by multiple coupled transmission lines (MTLs), and whose behavior when coupled to electron beams has not been sufficiently explored. We present the extension of the 1-D linearized Pierce theory to MTLs coupled to a single electron beam. We develop multiple formalisms to calculate the k-ω dispersion relation of the system and find that the existence of a growing wave solution is always guaranteed if the electron propagation constant is larger than or equal to the largest propagation constant of the MTL system. We verify our findings with illustrative examples that bring to light unique properties of the system in which growing waves were found to exist within finite bands of the electron propagation constant and also present possible means to improve the gain. By treating the beam-MTL interaction as distributed dependent current generators in the MTL, we derive relations characterizing the power flux and energy exchange between the beam and the MTLs. For the growing wave, we show that the beam always behaves as an energy source causing power flux along the transmission lines. The theory developed in this paper is the basis for the possible use of degenerate band edges in periodic MTL systems for HPM amplifiers.

A 3-D Analysis of a Microfabricated Ladder Slow-Wave Structure for a Millimeter-Wave Traveling-Wave Tube

The design and the analysis of a ladder slow-wave structure (SWS) operating at 50 GHz is presented. A 3-D particle-in-cell (PIC) modeling of a ladder SWS is presented for the first time. Compared with a conventional helix circuit, the ladder SWS provides wide bandwidth, high interaction impedance, and ease of manufacturing at millimeter wavelengths. A small-signal code based on Pierce's theory was developed to determine the dimensions and the small-signal characteristics of the device. Cold- and hot-test simulations were performed using High Frequency Structure Simulator and VORPAL codes. VORPAL, a 3-D PIC simulator that makes use of the conformal finite-difference time-domain method, predicts a small-signal gain of 15 dB and an instantaneous bandwidth of 6% for a 68-period ladder SWS that is driven by a 22-kV and 196-mA electron beam. Dispersion characteristics, large-signal characteristics, and nonlinear-beam dynamics are investigated.

Pierce's Theory of Signs (review)

Pierce's Theory of Signs (review)

Insights From One-Dimensional Linearized Pierce Theory About Wideband Traveling-Wave Tubes With High Space Charge

One-dimensional (1-D) linearized Pierce theory is examined for high space charge wideband traveling-wave tubes (TWTs). The more exact quartic equation is shown to provide reasonable predictions for the frequency-dependent small signal gain function, provided one has an accurate knowledge of the cold circuit phase velocity and space-charge reduction factor. Accurate knowledge of these parameters is particularly critical for predicting the high-frequency end of the positive gain region. The common simplified cubic equation is shown to underestimate the gain. On the other hand, quantitative comparisons show that the cubic solution remains acceptably accurate for first-trial design procedures where it offers advantages of scaling insights and incorporation into closed-form "optimized design" expressions. Guidelines are provided for approximating the growing wave's wavenumber in calculating the space-charge reduction factor. These guidelines are needed for all 1-D TWT models and simulations. Calculations illustrate that positive gain always involves the beam velocity exceeding the "hot" phase velocity of the wave.

Analysis of a broadband Q band folded waveguide traveling-wave tube

A highly reproducible, low-cost folded waveguide traveling-wave-tube amplifier is designed using the Pierce theory and a three-dimensional (3-D) particle-in-cell (PIC) code. The amplifier is designed to operate at 40-48 GHz with peak output radiation power of 200 W. Initial circuit parameters are obtained from the Pierce theory and circuit dispersion relations. A nonlinear large-signal performance of the amplifier is predicted from 3-D PIC simulations. Simulations show that the amplifier produces a saturated radiation power of 200 W at 44 GHz, corresponding to 5.6% electronic efficiency where the beam voltage and current are 21 kV and 0.17 A, respectively. A saturated 3-dB bandwidth is found to be 16% (40.5-47.5 GHz).

Acquisition of Nein and Nicht and the VP-Internal Subject Stage in German

Deprez and Pierce (1993) used negation data from German and other languages to support the hypothesis that subject noun phrases (NPs) originate within verb phrases (VPs). Deprez and Pierce argued that children go through an early stage of language acquisition during which subject NPs may optionally stay VP-internal. They claimed that during this stage, children do not distinguish between the negators nicht 'not' and nein 'no'. As a result, children produce negative utterances involving either negator, in which the negator occurs to the left of the subject. In their work, Deprez and Pierce did not systematically analyze German acquisition data, but rather relied on anecdotal data and examples cited in the literature. In this article, we analyze the negative utterances said by German-speaking children in transcripts of spontaneous speech. Contrary to Deprez and Pierce's claims, the results of our analyses indicate that German-speaking children distinguish between nicht and nein, using nicht in sentence-medial position for sentential negation and nein in sentence- initial position for anaphoric negation. Also contrary to Deprez and Pierce's theory, once negative utterances without overt subjects, anaphoric negatives, quantifier negatives, and unclear or stuttered negatives are excluded, there is no evidence that German-speaking children go through an early stage during which negation appears to the left of subject NPs.

00/00520 Environmental assessment and characterization of residues from coal processing and steel industry activities

A new method is presented to eliminate the undesirable end-effect appearing in the formation of a strip beam of charged particles according to the Pierce theory, without any additional device. By this method, a beam with finite length can be formed, regarding the cross section of the beam reasonably as a thin ellipse.An analytical solution is given for a rectilinear elliptic beam formation. It is troublesome, however, to perform the complete evaluation of the solution, but an approximation is also presented with sufficient accuracy.

Design of traveling wave tubes based on field theory

A method is described for the design of helix traveling wave tubes (TWT) which is based on the linear field analysis of the coupled beam-wave system. The dispersion relations are obtained by matching of radial admittances at boundaries instead of the individual field components. This approach provides flexibility in modeling various beam and circuit configurations with relative ease by choosing the appropriate admittance functions for each case. The method is illustrated for the case of a solid beam inside a sheath helix which is loaded externally by lossy dielectric material, a conducting cylinder, and axial vanes. Extension of the analysis to include a thin tape helix model is anticipated in the near future. The TWT model may be divided into axial regions to include velocity tapers, lossy materials and severs, with the helix geometry in each region varied arbitrarily. The relations between the AC velocities, current densities, and axial electric fields are used to derive a general expression for the new amplitudes of the three forward waves at each axial boundary. The sum of the fields for the three forward waves (two waves in a drift region) is followed to the circuit output. Numerical results of the field analysis are compared with the coupled-mode Pierce theory. A method is suggested for applying the field analysis to accurate design of practical TWT's that have a more complex circuit geometry, which starts with a simple measurement of the dispersion of the helix circuit. The field analysis may then be used to generate a circuit having properties very nearly equivalent to those of the actual circuit.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>