To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
A coaxial-output rolled strip pulse-forming line (RSPFL) with a dry structure is researched for the purpose of miniaturization and all-solid state of pulse-forming lines (PFL). The coaxial-output RSPFL consists of a coaxial-output electrode (COE) and a rolled strip line (RSL). The COE is characterized by quasi-coaxial structure, making the output pulse propagate along the axial direction with a small output inductance. The RSL is rolled on the COE, whose transmission characteristics are analyzed theoretically. It shows that the RSL can be regarded as a planar strip line when the rolling radius of the strip line is larger than 60 times of the thickness of the insulation dielectric layer of RSL. CST modeling was carried out to simulate the discharging characteristic of the coaxial-output RSPFL. It shows that the coaxial-output RSPFL can deliver a discharging pulse with a rise time <6 ns when the impedance of the RSL matches that of the COE, which confirms the theoretical analysis. A prototype of the coaxial-output RSPFL was developed. A 49-kV discharging pulse on a matched load was achieved when it was charged to 100 kV. The discharging waveform has a pulse width of 32 ns, with a rise time of 6 ns, which is consistent with the simulation waveform. An energy-storage density of 1.9 J/L was realized in the coaxial-output RSPFL. By the method of multi-stage connection in series, a much higher output voltage is convenient to be obtained.
A method to design the composite insulation structures in pulsed power systems is proposed in this paper. The theoretical bases for this method include the Weibull statistical distribution and the empirical insulation formula. A uniform formula to describe the reliability (R) for different insulation media such as solid, liquid, gas, vacuum, and vacuum surface is derived. The dependence curves of the normalized applied field on R are also obtained. These curves show that the normalized applied field decreases rapidly as R increases but the declining rates corresponding to different insulation media are different. In addition, if R is required to be higher than a given level, the normalized applied field should be smaller than a certain value. In practical design, the common range of the applied fields for different insulation media should be chosen to meet a global reliability requirement. In the end, the proposed method is demonstrated with a specific coaxial high-voltage vacuum insulator.
A useful procedure is described to rapidly obtain Bragg-reflection intensities from the FULLPROF suite, and the Bragg intensities can then be input into the GEST and the PECKCRYST programs for crystal-structure determination of small molecules. An example on using the new procedure for the structure determination from powder diffraction determination of hydrochlorothiazide (C7H8ClN3O4S2) is presented, and the powder-structure results obtained by the PECKCRYST program are in good agreement with previously reported single-crystal results.
In this work, we report on the growth of ultraviolet (UV) AlGaN/GaN multiple quantum wells (MQWs) structure using atomic layer deposition (ALD) technique. The AlGaN/GaN MQW sample grown on the sapphire substrate consisted of three GaN QWs and four AlGaN barriers comprised AlN/GaN superlattices (SLs). The root-mean-square value of the surface morphology was only 0.35 nm observed from the atomic force microscope image and no crack was found on the surface. Both of the high resolution X-ray diffraction curves and transmission electron microscope images showed sharp interfaces between SLs layers and QWs with good periodicity. These results demonstrate that the ALD could be a very useful technique for controlling the crystalline quality and thickness of the III-nitride epilayer.
In this paper we present the analytical description of two processes
dealing with the skin-layer ponderomotive acceleration method of fast ion
generation by a short laser pulse: ion density rippling in the underdense
plasma region and generation of ion beams by trapped electromagnetic field
in plasma. Some numerical examples of hydrodynamic simulation illustrating
these processes are shown. The effect of using the laser pulse consisting
of different frequency components on the ion density rippling and on
phenomena connected with trapped electromagnetic field is analyzed.
Generation of high speed dense plasma blocks is well known from
hydrodynamic theory and computations (PIC) with experimental confirmation
by Badziak et al. (2005) since ps laser
pulses with power above TW are available. These blocks may be used for
fusion flame generation (thermonuclear propagation) in uncompressed solid
state deuterium and tritium for very high gain uncomplicated operation in
power stations. Hydrodynamic theory from computations from the end of
1970s to recent, genuine two fluid computations support the skin layer
accelerations (SLA), by nonlinear (ponderomotive) forces as measured now
in details under the uniquely selected conditions to suppress relativistic
self-focusing by high contrast ratio and to keep plane geometry
interaction. It is shown how the now available PW-ps laser pulses may
provide the very extreme conditions for generating the fusion flames in
solid state density DT.
A joule level of XeF(C-A) laser optically pumped by a sectioned
surface discharge was developed. The irradiative intensity of pumping
source was diagnosed by calculating XeF2 photo-dissociation
wave evolvement which was photographed by a framing camera. The photon
flux in the wavelength region of 140 to 170nm is about 5 ×
1023 photon s−1cm−2, that
corresponds to the irradiative brightness temperature of more than 25000
K. The laser experiments were carried out in different conditions. The
maximum laser output energy of 2.5 J was obtained with the total
conversion efficiency of 0.1%.
In this paper the results of numerical computations of rippling
smoothing basing on the broad-band laser irradiation method for the laser
intensity range 1016−1017 W/cm2
and short-pulse (<10 ps) interaction with plasma are described.
Measurements of the ion emission from targets irradiated with
neodymium glass and iodine lasers were analyzed and a very significant
anomaly observed. The fastest ions with high charge number Z,
which usually are of megaelectron volt energy following the
relativistic self-focusing and nonlinear-force acceleration theory,
were reduced to less than 50 times lower energies when 1.2 ps laser
pulses of about 1 J were incident. We clarify this discrepancy by the
model of skin depth plasma front interaction in contrast to the
relativistic self-focusing with filament generation. This was indicated
also from the unique fact that the ion number was independent of the
laser intensity. The skin layer theory prescribes prepulse control and
lower (near relativistic threshold) laser intensities for
nonlinear-force-driven plasma blocks for high-gain ignition similar to
light ion beam fusion.
Email your librarian or administrator to recommend adding this to your organisation's collection.