Start current and growth rate in Smith–Purcell free-electron laser with dielectric-loaded cylindrical grating

Abstract We present an analytic theory for Smith–Purcell device in which a cylindrical metal–dielectric grating was derived by an annular electron beam propagating along the grating axis. A dispersion relation is obtained for azimuthally symmetric modes. Also, the first-order and second-order growth rates of the modes which are in phase with the beam are compared. It is shown that the second-order growth rate gives a more accurate description of beam–wave interaction for beams with larger thicknesses, as well as grating slots, with smaller depths and greater lengths. The start current for BWO operation of the SP-FEL is presented too. The importance of the minimum value of start current is that above it, the SP-FEL will operate as an oscillator, even in the absence of external feedback. In this case, the group velocity of the synchronous evanescent wave is negative, while the electron beam travels in the forward direction. It is shown in this paper that the dielectric and grating parameters affect the value of start current. So, by changing these parameters, the minimum value for the start current can be obtained.

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THz wave generation via electron beam-wave interaction in cylinderical photonic crystal waveguide

2011 IEEE International Symposium on Antennas and Propagation (APSURSI) ◽

10.1109/aps.2011.5996992 ◽

2011 ◽

Cited By ~ 3

Author(s):

A. I. Nashed ◽

S. K. Chaudhuri ◽

Safieddin Safavi-Naeini

Keyword(s):

Electron Beam ◽

Photonic Crystal ◽

Wave Interaction ◽

Wave Generation ◽

Photonic Crystal Waveguide ◽

Beam Wave ◽

Thz Wave ◽

Beam Wave Interaction

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Wave growth rate in a cylindrical metal waveguide with ion-channel guiding of a relativistic electron beam

Chinese Physics B ◽

10.1088/1674-1056/19/12/124101 ◽

2010 ◽

Vol 19 (12) ◽

pp. 124101 ◽

Cited By ~ 2

Author(s):

Hai-Rong Li ◽

Chang-Jian Tang ◽

Shun-Jin Wang

Keyword(s):

Growth Rate ◽

Electron Beam ◽

Ion Channel ◽

Relativistic Electron ◽

Relativistic Electron Beam ◽

Wave Growth ◽

Metal Waveguide ◽

Cylindrical Metal

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The root growth response to heterogeneous nitrate supply differs for Lupinus angustifolius and Lupinus pilosus

Australian Journal of Agricultural Research ◽

10.1071/ar00098 ◽

2001 ◽

Vol 52 (4) ◽

pp. 495 ◽

Cited By ~ 22

Author(s):

V. Dunbabin ◽

Z. Rengel ◽

A. Diggle

Keyword(s):

Growth Rate ◽

Root Growth ◽

Root System ◽

Nutrient Solution ◽

Growth Response ◽

Second Order ◽

Lupinus Angustifolius ◽

Average Growth ◽

First Order ◽

Tap Root

Little is known about the ability of legume root systems to respond to the heterogeneous supply of nitrate. A split-root nutrient solution experiment was set up to compare the root growth response of 2 lupin species, Lupinus angustifolius L. (dominant tap root and primary lateral system) and L. pilosus Murr. (minor tap root and well-developed lateral root system), to differentially supplied nitrate. These 2 species represent the extremes of the root morphology types present across the lupin germplasm. Nutrient solution containing low (250 M) or high (750 M) nitrate was supplied either uniformly, or split (high and low) between the upper and lower root system. The average growth rate and total root length of L. pilosus was 1.7 times that of L. angustifolius. For both species, the increased proliferation of roots in a high nitrate zone was accompanied by a decrease in root growth in the low nitrate zone, giving approximately the same total growth as the uniform low nitrate treatment. This correlative growth rate response was 15% larger for the first-order branches of L. pilosus than L. angustifolius. While few second-order branches grew for L. angustifolius, the second-order laterals of L. pilosus showed a 2-fold correlative root growth and branching response to the split treatments, with no difference in growth between the uniform high and low nitrate treatments. The second-order laterals thus proliferated in response to the differential supply of nitrate and not the absolute concentration. While the growth rate and branching of the second-order laterals of L. pilosus exhibited a typical correlative response, first-order branching was inhibited in all split treatments, regardless of whether the roots were in the high or low nitrate zone. This response was not seen in L. angustifolius. The difference in the root growth response of the 2 root system types to differentially supplied nitrate suggests a potential in the lupin germplasm for developing a line capable of greater nitrate capture from the soil profile.

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Omnibus Modeling of Listeria monocytogenes Growth Rates at Low Temperatures

Foods ◽

10.3390/foods10051099 ◽

2021 ◽

Vol 10 (5) ◽

pp. 1099

Author(s):

Vincenzo Pennone ◽

Ursula Gonzales Barron ◽

Kevin Hunt ◽

Vasco Cadavez ◽

Olivia McAuliffe ◽

...

Keyword(s):

Growth Rate ◽

Listeria Monocytogenes ◽

Case Fatality ◽

Second Order ◽

Lag Phase ◽

Model Parameters ◽

Growth Data ◽

Temperature Growth ◽

First Order ◽

Primary Model

Listeria monocytogenes is a pathogen of considerable public health importance with a high case fatality. L. monocytogenes can grow at refrigeration temperatures and is of particular concern for ready-to-eat foods that require refrigeration. There is substantial interest in conducting and modeling shelf-life studies on L. monocytogenes, especially relating to storage temperature. Growth model parameters are generally estimated from constant-temperature growth experiments. Traditionally, first-order and second-order modeling (or primary and secondary) of growth data has been done sequentially. However, omnibus modeling, using a mixed-effects nonlinear regression approach, can model a full dataset covering all experimental conditions in one step. This study compared omnibus modeling to conventional sequential first-order/second-order modeling of growth data for five strains of L. monocytogenes. The omnibus model coupled a Huang primary model for growth with secondary models for growth rate and lag phase duration. First-order modeling indicated there were small significant differences in growth rate depending on the strain at all temperatures. Omnibus modeling indicated smaller differences. Overall, there was broad agreement between the estimates of growth rate obtained by the first-order and omnibus modeling. Through an appropriate choice of fixed and random effects incorporated in the omnibus model, potential errors in a dataset from one environmental condition can be identified and explored.

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Tuning the Dynamics of Boronic Acid Hydrazones and Oximes with pH and Redox Control

10.26434/chemrxiv.13480275 ◽

2020 ◽

Author(s):

Gun Su Han ◽

Dylan Domaille

Keyword(s):

Kinetic Model ◽

Boronic Acid ◽

Half Life ◽

Acid Catalyst ◽

Forward Direction ◽

Ph Control ◽

Second Order ◽

Redox Control ◽

Aqueous Buffer ◽

First Order

<div>The reaction between acyl hydrazide and methylhydroxylamine with 2-formylphenylboronic acid (2-FPBA) are measured in aqueous buffer at concentrations appropriate for bioconjuagtion (0.1 mM). The data are well-described by a reversible kinetic model that is second-order in the forward direction (10<sup>2 </sup>– 10<sup>3</sup> M<sup>-1 </sup>s<sup>-1</sup>) and first-order in hydrolysis (~10<sup>-4</sup> s<sup>-1</sup>). We further show the resulting diazaborines (DAB) and oximes undergo exchange with competing nucleophiles, and the rate of exchange can be tuned with pH control. Finally, we demonstrate that treatment with H<sub>2</sub>O<sub>2</sub> converts the proximal boronic acid catalyst to a phenol, which abolishes the rapid dynamics, and increases the hydrolytic half-life of the resulting oxime from 50 minutes to 6 months.</div><div><br></div>

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Tuning the Dynamics of Boronic Acid Hydrazones and Oximes with pH and Redox Control

10.26434/chemrxiv.13480275.v1 ◽

2020 ◽

Author(s):

Gun Su Han ◽

Dylan Domaille

Keyword(s):

Kinetic Model ◽

Boronic Acid ◽

Half Life ◽

Acid Catalyst ◽

Forward Direction ◽

Ph Control ◽

Second Order ◽

Redox Control ◽

Aqueous Buffer ◽

First Order

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Nonlinear dynamics of electron bunches in the presence of dissipative effects

Journal of Plasma Physics ◽

10.1017/s0022377898007442 ◽

1999 ◽

Vol 61 (2) ◽

pp. 275-293 ◽

Cited By ~ 3

Author(s):

C. KRAFFT ◽

A. VOLOKITIN ◽

M. FLÉ

Keyword(s):

Nonlinear Dynamics ◽

Electron Beam ◽

Wave Interaction ◽

Beam Wave ◽

Trapped Particles ◽

Electron Bunches ◽

Dissipative Effects ◽

Beam Interaction ◽

Beam Wave Interaction ◽

Nonlinear Regimes

The transition phase between two nonlinear regimes of electron-beam–wave interaction depending on the amplitude and the nature of the effective dissipation is investigated with the help of numerical simulations. Effective dissipation due to wave escaping to infinity out of the beam–wave interaction region as well as to collisions in the background plasma is considered. If the dissipation is strong enough, the evolution of the electron beam proceeds in a general way, independently of the type of dissipation and of the nature of the considered waves: structures of strongly concentrated electron bunches are formed. These bunches are not trapped in the wave, and decelerate continuously owing to friction on waves: in the presence of dissipation, the usual quasiperiodic exchange of energy between the wave and the trapped particles, which prevents the wave from collapsing, does not occur. Considering beam interaction with a finite number of waves (modulated wave packet), it is shown that, if the dissipation is strong enough, the structure of electron bunches is dynamically stable in a range of times exceeding several characteristic times of their formation.

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