247 research outputs found
Raman tensor analysis of hexagonal polyoxymethylene and its application to study the molecular arrangement in highly crystalline electrospun nanofibers
The orientation dependence in space of Raman-active vibrations in the hexagonal structure of polyoxymethylene (POM) is discussed in terms of Raman tensor elements as intrinsic physical parameters of the lattice. The variation of polarized intensity for the A1 and the E1 vibrational modes with respect to the POM molecular orientation is systematically studied, from both theoretical and experimental viewpoints, according to the symmetry assignments of each vibrational mode. A set of working equations including the Raman selection rules associated with the A1 and the E1 modes and the orientation distribution function are explicitly formulated and validated by means of a least-square fitting procedure on experimental data. In addition, an approach based on the introduction of orientation distribution functions is applied to quantitatively assess and compare on a statistical base the molecular orientation of two different types of electrospun POM nanofibers. Copyright (c) 2012 John Wiley & Sons, Ltd
Transverse Dynamics and Energy Tuning of Fast Electrons Generated in Sub-Relativistic Intensity Laser Pulse Interaction with Plasmas
The regimes of quasi-mono-energetic electron beam generation were
experimentally studied in the sub-relativistic intensity laser plasma
interaction. The observed electron acceleration regime is unfolded with
two-dimensional-particle-in-cell simulations of laser-wakefield generation in
the self-modulation regime.Comment: 10 pages, 5 figure
Sero- and Molecular Epidemiology of HIV-1 in Papua Province, Indonesia
Background: human immunodeficiency virus (HIV) infection and acquired immune deficiency syndrome (AIDS) cause serious health problems and affect the Indonesian economy. Papua province has the highest prevalence of HIV infection in the country; however, epidemiological data are limited. Therefore, in order to reveal the current situation of HIV/AIDS in Papua province, sero- and molecular epidemiological studies of HIV were conducted. Methods: serological tests were conducted on 157 healthy individuals from the general population residing in Paniai, Papua. In addition, a molecular epidemiological study was then conducted on HIV type 1 (HIV-1) genes derived from infected individuals. Peripheral blood samples from HIV-1-positive individuals and 15 additionally enrolled, previously confirmed HIV-1-positive individuals were subjected to a genotypic analysis. Results: serological tests revealed that 2 out of 157 (1.27%) healthy individuals were HIV-positive. In addition, HIV-1 subtyping revealed that subtype B and CRF01_AE were the major subtype and circulating recombinant form (CRF) of HIV-1 prevalent in the region, while subtype A1 and a recombinant form including viral gene fragments of CRF01_AE and subtype B was also detected. In addition, HIV drug resistance-associated major mutations were detected in the reverse transcriptase gene derived from infected individual on antiretroviral therapy. Conclusion: these results provide important information for clearer understanding on the current situation of HIV/AIDS in Papua province in Indonesia
Soft X-ray harmonic comb from relativistic electron spikes
We demonstrate a new high-order harmonic generation mechanism reaching the
`water window' spectral region in experiments with multi-terawatt femtosecond
lasers irradiating gas jets. A few hundred harmonic orders are resolved, giving
uJ/sr pulses. Harmonics are collectively emitted by an oscillating electron
spike formed at the joint of the boundaries of a cavity and bow wave created by
a relativistically self-focusing laser in underdense plasma. The spike
sharpness and stability are explained by catastrophe theory. The mechanism is
corroborated by particle-in-cell simulations
Stability improvement of a laser-accelerated electron beam and the pulse width measurement of the electron beam
Laser wakefield acceleration has the possibility to generate an ultrashort electron beam of the order of femtoseconds or less. In applications of these laser accelerated electron beams, stable and controllable electron beams are necessary. A high stability electron bunch is generated by laser wakefield acceleration with the help of a colliding laser pulse (optical injection). Stable and monoenergetic electron beams have been generated in the self-injection scheme of laser acceleration by using a Nitrogen gas jet target. The electron interaction with the laser field results in transverse oscillations of the electron beam. From the electron oscillation period dependence on the electron energy we find that the electron beam width is equal to 1.7 fs (rms).Π ΠΏΡΠΎΡΠ΅ΡΡΠ΅ ΡΡΠΊΠΎΡΠ΅Π½ΠΈΡ ΠΊΠΈΠ»ΡΠ²Π°ΡΠ΅ΡΠ½ΡΠΌΠΈ Π²ΠΎΠ»Π½Π°ΠΌΠΈ Π²ΠΎΠ·ΠΌΠΎΠΆΠ½Π° Π³Π΅Π½Π΅ΡΠ°ΡΠΈΡ ΡΠ²Π΅ΡΡ
ΠΊΠΎΡΠΎΡΠΊΠΈΡ
ΡΠ»Π΅ΠΊΡΡΠΎΠ½Π½ΡΡ
ΠΏΡΡΠΊΠΎΠ² ΡΠ΅ΠΌΡΠΎΡΠ΅ΠΊΡΠ½Π΄Π½ΠΎΠΉ Π΄Π»ΠΈΡΠ΅Π»ΡΠ½ΠΎΡΡΡΡ. ΠΠ»Ρ ΠΏΡΠΈΠ»ΠΎΠΆΠ΅Π½ΠΈΠΉ ΡΡΠ΅Π±ΡΡΡΡΡ ΡΠ»Π΅ΠΊΡΡΠΎΠ½Π½ΡΠ΅ ΠΏΡΡΠΊΠΈ Ρ Π²ΠΎΡΠΏΡΠΎΠΈΠ·Π²ΠΎΠ΄ΠΈΠΌΡΠΌΠΈ ΠΈ ΠΊΠΎΡΡΠΎΠ»ΠΈΡΡΠ΅ΠΌΡΠΌΠΈ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠ°ΠΌΠΈ. ΠΠΏΡΠΈΡΠ΅ΡΠΊΠ°Ρ ΠΈΠ½ΠΆΠ΅ΠΊΡΠΈΡ, ΠΈΡΠΏΠΎΠ»ΡΠ·ΡΡΡΠ°Ρ ΡΡΠ°Π»ΠΊΠΈΠ²Π°ΡΡΠΈΠ΅ΡΡ Π»Π°Π·Π΅ΡΠ½ΡΠ΅ ΠΈΠΌΠΏΡΠ»ΡΡΡ, ΠΎΠ±Π΅ΡΠΏΠ΅ΡΠΈΠ²Π°Π΅Ρ Π²ΡΡΠΎΠΊΡΡ Π²ΠΎΡΠΏΡΠΎΠΈΠ·Π²ΠΎΠ΄ΠΈΠΌΠΎΡΡΡ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠΎΠ² ΠΏΡΡΠΊΠΎΠ² ΡΡΠΊΠΎΡΠ΅Π½Π½ΡΡ
ΡΠ»Π΅ΠΊΡΡΠΎΠ½ΠΎΠ². ΠΠΎΠ½ΠΎΡΠ½Π΅ΡΠ³Π΅ΡΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΠΏΡΡΠΊΠΈ ΡΠ»Π΅ΠΊΡΡΠΎΠ½ΠΎΠ² Ρ Π²ΠΎΡΠΏΡΠΎΠΈΠ·Π²ΠΎΠ΄ΠΈΠΌΡΠΌΠΈ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠ°ΠΌΠΈ Π±ΡΠ»ΠΈ ΠΏΠΎΠ»ΡΡΠ΅Π½Ρ ΠΏΡΠΈ Β«ΡΠ°ΠΌΠΎΠΈΠ½ΠΆΠ΅ΠΊΡΠΈΠΈΒ» Π² ΠΊΠΈΠ»ΡΠ²Π°ΡΠ΅ΡΠ½ΡΡ Π²ΠΎΠ»Π½Ρ Π² ΡΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠ°Ρ
, ΠΈΡΠΏΠΎΠ»ΡΠ·ΡΡΡΠΈΡ
Π² ΠΊΠ°ΡΠ΅ΡΡΠ²Π΅ ΠΌΠΈΡΠ΅Π½ΠΈ ΡΡΡΡΡ Π°Π·ΠΎΡΠ°. ΠΠ·Π°ΠΈΠΌΠΎΠ΄Π΅ΠΉΡΡΠ²ΠΈΠ΅ ΡΠ»Π΅ΠΊΡΡΠΎΠ½ΠΎΠ² Ρ ΠΈΠ·Π»ΡΡΠ΅Π½ΠΈΠ΅ΠΌ Π»Π°Π·Π΅ΡΠ½ΠΎΠ³ΠΎ ΠΈΠΌΠΏΡΠ»ΡΡΠ° ΠΏΡΠΈΠ²ΠΎΠ΄ΠΈΡ ΠΊ ΠΏΠΎΠΏΠ΅ΡΠ΅ΡΠ½ΡΠΌ ΠΎΡΡΠΈΠ»Π»ΡΡΠΈΡΠΌ ΡΠ»Π΅ΠΊΡΡΠΎΠ½Π½ΠΎΠ³ΠΎ ΠΏΡΡΠΊΠ°. ΠΠ½Π°Π»ΠΈΠ· Π½Π°Π±Π»ΡΠ΄Π°Π΅ΠΌΠΎΠΉ Π² ΡΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠ΅ Π·Π°Π²ΠΈΡΠΈΠΌΠΎΡΡΠΈ ΠΏΠ΅ΡΠΈΠΎΠ΄Π° ΠΎΡΡΠΈΠ»Π»ΡΡΠΈΠΉ ΠΎΡ ΡΠ½Π΅ΡΠ³ΠΈΠΈ ΡΠ»Π΅ΠΊΡΡΠΎΠ½ΠΎΠ² ΠΏΠΎΠ·Π²ΠΎΠ»ΡΠ΅Ρ Π½Π°ΠΉΡΠΈ Π΄Π»ΠΈΡΠ΅Π»ΡΠ½ΠΎΡΡΡ ΡΠ»Π΅ΠΊΡΡΠΎΠ½Π½ΠΎΠ³ΠΎ ΠΏΡΡΠΊΠ°, ΡΠ°Π²Π½ΡΡ 1.7 ΡΡ.Π ΠΏΡΠΎΡΠ΅ΡΡ ΠΏΡΠΈΡΠΊΠΎΡΠ΅Π½Π½Ρ ΠΊΡΠ»ΡΠ²Π°ΡΠ΅ΡΠ½ΠΈΠΌΠΈ Ρ
Π²ΠΈΠ»ΡΠΌΠΈ ΠΌΠΎΠΆΠ»ΠΈΠ²Π° Π³Π΅Π½Π΅ΡΠ°ΡΡΡ Π½Π°Π΄ΠΊΠΎΡΠΎΡΠΊΠΈΡ
Π΅Π»Π΅ΠΊΡΡΠΎΠ½Π½ΠΈΡ
ΠΏΡΡΠΊΡΠ² ΡΠ΅ΠΌΡΠΎΡΠ΅ΠΊΡΠ½Π΄Π½ΠΎΡ ΡΡΠΈΠ²Π°Π»ΠΎΡΡΡ. ΠΠ»Ρ Π΄ΠΎΠ΄Π°ΡΠΊΡΠ² ΠΏΠΎΡΡΡΠ±Π½Ρ Π΅Π»Π΅ΠΊΡΡΠΎΠ½Π½Ρ ΠΏΡΡΠΊΠΈ Π· Π²ΡΠ΄ΡΠ²ΠΎΡΡΡΡΠΈΠΌΠΈ Ρ ΠΊΠΎΡΡΠΎΠ»ΡΡΡΠΈΠΌΠΈ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠ°ΠΌΠΈ. ΠΠΏΡΠΈΡΠ½Π° ΡΠ½ΠΆΠ΅ΠΊΡΡΡ, ΡΠΎ Π²ΠΈΠΊΠΎΡΠΈΡΡΠΎΠ²ΡΡ Π·ΡΡΡΠΎΠ²Ρ
ΡΡΡΡ Π»Π°Π·Π΅ΡΠ½Ρ ΡΠΌΠΏΡΠ»ΡΡΠΈ, Π·Π°Π±Π΅Π·ΠΏΠ΅ΡΡΡ Π²ΠΈΡΠΎΠΊΡ Π²ΡΠ΄ΡΠ²ΠΎΡΡΠ²Π°Π½ΡΡΡΡ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΡΠ² ΠΏΡΡΠΊΡΠ² ΠΏΡΠΈΡΠΊΠΎΡΠ΅Π½ΠΈΡ
Π΅Π»Π΅ΠΊΡΡΠΎΠ½ΡΠ². ΠΠΎΠ½ΠΎΠ΅Π½Π΅ΡΠ³Π΅ΡΠΈΡΠ½Ρ ΠΏΡΡΠΊΠΈ Π΅Π»Π΅ΠΊΡΡΠΎΠ½ΡΠ² Π· Π²ΡΠ΄ΡΠ²ΠΎΡΡΠ²Π°Π½ΠΈΠΌΠΈ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠ°ΠΌΠΈ Π±ΡΠ»ΠΈ ΠΎΡΡΠΈΠΌΠ°Π½Ρ ΠΏΡΠΈ Β«ΡΠ°ΠΌΠΎΡΠ½ΠΆΠ΅ΠΊΡΡΡΒ» Π² ΠΊΡΠ»ΡΠ²Π°ΡΠ΅ΡΠ½Ρ Ρ
Π²ΠΈΠ»Ρ Π² Π΅ΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠ°Ρ
, Π² ΡΠΊΠΈΡ
Π² ΡΠΊΠΎΡΡΡ ΠΌΡΡΠ΅Π½Ρ Π²ΠΈΠΊΠΎΡΠΈΡΡΠΎΠ²ΡΠ²Π°Π»Π°ΡΡ ΡΡΡΡΠΌΡΠ½Ρ Π°Π·ΠΎΡΡ. ΠΠ·Π°ΡΠΌΠΎΠ΄ΡΡ Π΅Π»Π΅ΠΊΡΡΠΎΠ½ΡΠ² Π· Π²ΠΈΠΏΡΠΎΠΌΡΠ½ΡΠ²Π°Π½Π½ΡΠΌ Π»Π°Π·Π΅ΡΠ½ΠΎΠ³ΠΎ ΡΠΌΠΏΡΠ»ΡΡΡ ΠΏΡΠΈΠ·Π²ΠΎΠ΄ΠΈΡΡ Π΄ΠΎ ΠΏΠΎΠΏΠ΅ΡΠ΅ΡΠ½ΠΈΡ
ΠΎΡΡΠΈΠ»ΡΡΡΠΉ Π΅Π»Π΅ΠΊΡΡΠΎΠ½Π½ΠΎΠ³ΠΎ ΠΏΡΡΠΊΠ°. ΠΠ½Π°Π»ΡΠ· ΡΠΏΠΎΡΡΠ΅ΡΡΠ³Π°ΡΡΠΎΡ Π² Π΅ΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΡ Π·Π°Π»Π΅ΠΆΠ½ΠΎΡΡΡ ΠΏΠ΅ΡΡΠΎΠ΄Ρ ΠΎΡΡΠΈΠ»ΡΡΡΠΉ Π²ΡΠ΄ Π΅Π½Π΅ΡΠ³ΡΡ Π΅Π»Π΅ΠΊΡΡΠΎΠ½ΡΠ² Π΄ΠΎΠ·Π²ΠΎΠ»ΡΡ Π·Π½Π°ΠΉΡΠΈ ΡΡΠΈΠ²Π°Π»ΡΡΡΡ Π΅Π»Π΅ΠΊΡΡΠΎΠ½Π½ΠΎΠ³ΠΎ ΠΏΡΡΠΊΠ°, ΡΠΊΠ° Π΄ΠΎΡΡΠ²Π½ΡΡ 1.7 ΡΡ
High-order alloharmonics produced by nonperiodic drivers
High-order harmonics are ubiquitous in nature and present in electromagnetic,
acoustic, and gravitational waves. They are generated by periodic nonlinear
processes or periodic high-frequency pulses. However, this periodicity is often
inexact, such as that in chirped (frequency-swept) optical waveforms or
interactions with nonstationary matter -- for instance, reflection from
accelerating mirrors. Spectra observed in such cases contain complicated sets
of harmonic-like fringes. We encountered such fringes in our experiment on
coherent extreme ultraviolet generation via BISER, and could not interpret them
using currently available knowledge. Here, we present a comprehensive theory
based on interference of harmonics with different orders fully explaining the
formation of these fringes, which we call alloharmonics. Like atomic spectra,
the complex alloharmonic spectra depend on several integer numbers and bear a
unique imprint of the emission process, which the theory can decipher, avoiding
confusion or misinterpretation. We also demonstrate the alloharmonics in
simulations of gravitational waves emitted by binary black hole mergers.
Further, we predict the presence of alloharmonics in the radio spectra of
pulsars and in optical frequency combs, and propose their use for measurement
of extremely small accelerations necessary for testing gravity theories. The
alloharmonics phenomenon generalizes classical harmonics and is critical in
research fields such as laser mode locking, frequency comb generation,
attosecond pulse generation, pulsar studies, and future gravitational wave
spectroscopy.Comment: 29 pages, 9 figures, 3 table
Observation of Burst Intensification by Singularity Emitting Radiation generated from relativistic plasma with a high-intensity laser
Coherent x-rays via the Burst Intensification by Singularity Emitting Radiation (BISER) mechanism are generated from relativistic plasma in helium gas target. A broad modulation of the BISER spectrum, which is significantly wider than the harmonic order, is observed and characterized. In particular, we found that the modulation period can be as large as 41 eV
Organic waste as a sustainable feedstock for platform chemicals
Biorefineries have been established since the 1980s for biofuel production, and there has been a switch lately from first to second generation feedstocks in order to avoid the food versus fuel dilemma. To a lesser extent, many opportunities have been investigated for producing chemicals from biomass using by-products of the present biorefineries, simple waste streams. Current facilities apply intensive pre-treatments to deal with single substrate types such as carbohydrates. However, most organic streams such as municipal solid waste or algal blooms present a high complexity and variable mixture of molecules, which makes specific compound production and separation difficult. Here we focus on flexible anaerobic fermentation and hydrothermal processes that can treat complex biomass as a whole to obtain a range of products within an integrated biorefinery concept
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