46 research outputs found
Optical vortices enabled by structural vortices
The structural symmetry of solids plays an important role in defining their
linear and nonlinear optical properties. The quest for versatile,
cost-effective, large-scale, and defect-free approaches and materials platforms
for tailoring structural and optical properties on demand has been underway for
decades. We experimentally demonstrate a bottom-up self-assembly-based organic
engineered material comprised of synthesized molecules with large dipole
moments that are crystallized into a spherulite structure. The molecules align
in an azimuthal direction, resulting in a vortex polarity with spontaneously
broken symmetry leading to strong optical anisotropy and nonlinear optical
responses. These unique polarization properties of the judiciously designed
organic spherulite combined with the symmetry of structured optical beams
enable a plethora of new linear and nonlinear light-matter interactions,
including the generation of optical vortex beams with complex spin states and
on-demand topological charges at the fundamental, doubled, and tripled
frequencies. The results of this work are likely to enable numerous
applications in areas such as high-dimensional quantum information processing,
with large capacity and high security. The demonstrated spherulite crystals
facilitate stand-alone micro-scale devices that rely on the unique micro-scale
spontaneous vortex polarity that is likely to enable future applications for
high-dimensional quantum information processing, spatiotemporal optical
vortices, and a novel platform for optical manipulation and trapping
A Systematic Approach for Inertial Sensor Calibration of Gravity Recovery Satellites and Its Application to Taiji-1 Mission
High-precision inertial sensors or accelerometers can provide us references
of free-falling motions in gravitational field in space. They serve as the key
payloads for gravity recovery missions such as the CHAMP, the GRACE-type
missions, and the planned Next Generation Gravity Missions. In this work, a
systematic method of electrostatic inertial sensor calibrations for gravity
recovery satellites is suggested, which is applied to and verified with the
Taiji-1 mission. With this method, the complete operating parameters including
the scale factors, the center of mass offset vector and the intrinsic biased
acceleration can be precisely calibrated with only two sets of short-term
in-orbit experiments. Taiji-1 is the first technology demonstration satellite
of the "Taiji Program in Space", which, in its final extended phase in 2022,
could be viewed as operating in the mode of a high-low satellite-to-satellite
tracking gravity mission. Based on the calibration principles, swing maneuvers
with time span about 200 s and rolling maneuvers for 19 days were conducted by
Taiji-1 in 2022. The inertial sensor's operating parameters are precisely
re-calibrated with Kalman filters and are updated to the Taiji-1 science team.
Data from one of the sensitive axis is re-processed with the updated operating
parameters, and the performance is found to be slightly improved compared with
former results. This approach could be of high reference value for the
accelerometer or inertial sensor calibrations of the GFO, the Chinese
GRACE-type mission, and the Next Generation Gravity Missions. This could also
shed some light on the in-orbit calibrations of the ultra-precision inertial
sensors for future GW space antennas because of the technological inheritance
between these two generations of inertial sensors.Comment: 24 pages, 19 figure
Two new species of Hirsutella (Ophiocordycipitaceae, Sordariomycetes) that are parasitic on lepidopteran insects from China
Hirsutella are globally distributed entomopathogenic fungi that offer important economic applications in biological control and biomedicine. Hirsutella was suppressed in favour of Ophiocordyceps affected by the ending of dual nomenclature for pleomorphic fungi in 2011. Currently, Hirsutella has been resurrected as a genus under Ophiocordycipitaceae. In this study, we introduce two new species of Hirsutella, based on morphological and phylogenetic analyses. Hirsutella flava and H. kuankuoshuiensis are pathogenic on different species of larval Lepidoptera in China. Hirsutella flava primarily differs from related species by its awl-shaped base; long and narrow neck, 24–40.8 × 2.2–2.5 μm; long and narrow cymbiform or fusoid conidia, 6.5–10 × 2.1–4.3 μm. Hirsutella kuankuoshuiensis has two types of phialides and distinctive 9.9–12.6 × 2.7–4.5 μm, clavate or botuliform conidia. The distinctions amongst the new species and phylogenetic relationships with other Hirsutella species are discussed
Effect of Crystal-shaped Additives of Precipitated Calcium Carbonate on the Whiteness of Modified Fly Ash and Hand Sheets
Fly ash was modified using calcium oxide and carbon dioxide. The morphology of precipitated calcium carbonate was controlled by adding different crystal-shape-forming additives. Effects of sodium hexametaphosphate, zinc chloride, sodium tetraborate decahydrate, and aluminium chloride on the crystal shape of precipitated calcium carbonate were studied. The effects of crystal-shaped additives of precipitated calcium on the whiteness of modified fly ash and hand sheets were analyzed. The results showed that the addition of ZnCl2 (0.35%) can play a role in coating fly ash well. The coating effect of the acicular, chain, and lamellar precipitated calcium carbonate on the surface of fly ash was slightly less effective than that of globular crystals
Analysis of the Metabolic Pathways Affected by Poly(γ-glutamic Acid) in Arabidopsis thaliana Based on GeneChip Microarray
Plant
growth is promoted by polyÂ(γ-glutamic acid) (γ-PGA).
However, the molecular mechanism underlying such promotion is not
yet well understood. Therefore, we used GeneChip microarrays to explore
the effects of γ-PGA on gene transcription in Arabidopsis thaliana. Our results revealed 299 genes
significantly regulated by γ-PGA. These differently expressed
genes participate mainly in metabolic and cellular processes and in
stimuli responses. The metabolic pathways linked to these differently
expressed genes were also investigated. A total of 64 of the 299 differently
expressed genes were shown to be directly involved in 24 pathways
such as brassinosteroid biosynthesis, α-linolenic acid metabolism,
phenylpropanoid biosynthesis, and nitrogen metabolism, all of which
were influenced by γ-PGA. The analysis demonstrated that γ-PGA
promoted nitrogen assimilation and biosynthesis of brassinosteroids,
jasmonic acid, and lignins, providing a better explanation for why
γ-PGA promotes growth and enhances stress tolerance in plants
Analysis of the Metabolic Pathways Affected by Poly(γ-glutamic Acid) in Arabidopsis thaliana Based on GeneChip Microarray
Plant
growth is promoted by polyÂ(γ-glutamic acid) (γ-PGA).
However, the molecular mechanism underlying such promotion is not
yet well understood. Therefore, we used GeneChip microarrays to explore
the effects of γ-PGA on gene transcription in Arabidopsis thaliana. Our results revealed 299 genes
significantly regulated by γ-PGA. These differently expressed
genes participate mainly in metabolic and cellular processes and in
stimuli responses. The metabolic pathways linked to these differently
expressed genes were also investigated. A total of 64 of the 299 differently
expressed genes were shown to be directly involved in 24 pathways
such as brassinosteroid biosynthesis, α-linolenic acid metabolism,
phenylpropanoid biosynthesis, and nitrogen metabolism, all of which
were influenced by γ-PGA. The analysis demonstrated that γ-PGA
promoted nitrogen assimilation and biosynthesis of brassinosteroids,
jasmonic acid, and lignins, providing a better explanation for why
γ-PGA promotes growth and enhances stress tolerance in plants
Recent advances in bio-based multi-products of agricultural Jerusalem artichoke resources
Abstract The Jerusalem artichoke is a perennial plant that belongs to the sunflower family. As a non-grain crop, Jerusalem artichoke possesses a number of desirable characteristics that make it a valuable feedstock for biorefinery, such as inulin content, rapid growth, strong adaptability, and high yields. This review provides a comprehensive introduction to renewable Jerusalem artichoke-based biomass resources and recent advances in bio-based product conversion. Furthermore, we discuss the latest in the development of inulinase-producing microorganisms and enhanced inulin hydrolysis capacity of microbes by genetic engineering, which lead to a more cost-effective Jerusalem artichoke biorefinery. The review is aimed at promoting Jerusalem artichoke industry and new prospects for higher value-added production
Author response for "Trachytic magmatism and <scp>Nb–</scp> rare earth element mineralization in the Pingli area, North Daba Mountain: Insights from geochronology and geochemistry"
Study on low-frequency noise characteristics of hydrogen-terminated diamond FETs
In this work, the low frequency noise (LFN) characteristics of Hydrogen-terminated diamond FETs are investigated. Both generation-recombination (GR) noise and flicker noise (1/f noise) are found to contribute to the LFN spectrum. The characteristic frequency of f01 = 0.1 Hz, f02 = 30 Hz, f03 = 300 Hz and corresponding effective trap density (Neff) of the GR centers are obtained. By changing the LFN measurement temperature, a trap activation energy level (Ea) of 0.12 eV is extracted from an Arrhenius plot. The dominant mechanism of the 1/f noise for the H-terminated diamond FETs follows the correlated mobility fluctuations (CMF) model. By fitting the experimental data to the CMF model, the trap density and scattering coefficient of the carriers are extracted to be 6.4 x 10^20 eV−1 cm−3 and 4 x 10^5 V·s/C. At last, the trap density of the H-terminated diamond FETs is compared with other state-of-the-art GaN and Si based devices. A moderate trap density was obtained without any interface optimization, suggesting that H-terminated diamond FETs could be a promising future technology for power electronics