2,113 research outputs found
Effect of Litter Addition on Amino Acid Content and Composition in Alpine Meadow Soil
Litter plays an important role in plant-soil nutrient cycling. However, the response of soil amino acid pools to litter input is unclear. Therefore, the aim of this study was to explore the effects of litter addition on the content and composition of soil amino acids in an alpine meadow soil. Soil was amended with litter of its dominant species, Kobresia graminifolia, and incubated for four weeks. Our results show that litter addition significantly increased the exchangeable amino acid content and protease activity in the soil. These results are crucial for understanding the amino acid cycling in soil
The Tensor Current Divergence Equation in U(1) Gauge Theories is Free of Anomalies
The possible anomaly of the tensor current divergence equation in U(1) gauge
theories is calculated by means of perturbative method. It is found that the
tensor current divergence equation is free of anomalies.Comment: Revtex4, 7 pages, 2 figure
Interface Engineering of Biomass-Derived Carbon used as Ultrahigh-Energy-Density and Practical Mass-Loading Supercapacitor Electrodes
The development of flexible electrodes with high mass loading and efficient electron/ion transport is of great significance but still remains the challenge of innovating suitable electrode structures for high energy density application. Herein, for the first time, lignosulfonate-derived N/S-co-doped graphene-like carbon is in situ formed within an interface engineered cellulose textile through a sacrificial template method. Both experimental and theoretical calculations disclose that the formed pomegranate-like structure with continuous conductive pathways and porous characteristics allows sufficient ion/electron transport throughout the entire structures. As a result, the obtained flexible electrode delivers a remarkable integrated capacitance of 6534 mF cm−2 (335.1 F g−1) and a superior stability at an industrially applicable mass loading of 19.5 mg cm−2. A pseudocapacitive cathode with ultrahigh capacitance of 7000 mF cm−2 can also be obtained based on the same electrode structure engineering. The as-assembled asymmetric supercapacitor achieves a high areal capacitance of 3625 mF cm−2, and a maximum energy density of 1.06 mWh cm−2, outperforms most of other reported high-loading supercapacitors. This synthesis method and structural engineering strategy can provide materials design concepts and a wide range of applications in the fields of energy storage beyond supercapacitors
Detecting Extra Dimension by Helium-like Ions
Considering that gravitational force might deviate from Newton's
inverse-square law and become much stronger in small scale, we present a method
to detect the possible existence of extra dimensions in the ADD model. By
making use of an effective variational wave function, we obtain the
nonrelativistic ground energy of a helium atom and its isoelectronic sequence.
Based on these results, we calculate gravity correction of the ADD model. Our
calculation may provide a rough estimation about the magnitude of the
corresponding frequencies which could be measured in later experiments.Comment: 8 pages, no figures, accepted by Mod. Phys. Lett.
A Unified Quantum NOT Gate
We study the feasibility of implementing a quantum NOT gate (approximate)
when the quantum state lies between two latitudes on the Bloch's sphere and
present an analytical formula for the optimized 1-to- quantum NOT gate. Our
result generalizes previous results concerning quantum NOT gate for a quantum
state distributed uniformly on the whole Bloch sphere as well as the phase
covariant quantum state. We have also shown that such 1-to- optimized NOT
gate can be implemented using a sequential generation scheme via matrix product
states (MPS)
Effect of gauge boson mass on the phase structure of QED
Dynamical chiral symmetry breaking (DCSB) in QED with finite gauge
boson mass is
studied in the framework of the rainbow approximation of Dyson-Schwinger
equations.
By adopting a simple gauge boson propagator ansatz at finite temperature, we
first numerically solve the
Dyson-Schwinger equation for the fermion self-energy to
determine the chiral phase diagram of QED with finite gauge boson mass
at finite chemical potential and finite temperature, then we study the
effect of the finite gauge mass on the phase diagram of QED. It is found
that the gauge boson mass suppresses the occurrence of
DCSB. The area of the region in the chiral phase diagram corresponding to
DCSB phase decreases as
the gauge boson mass increases. In
particular, chiral symmetry gets restored when is above a
certain critical value. In this paper, we use DCSB to describe the
antiferromagnetic order and use the gauge boson mass to describe the
superconducting order. Our results give qualitatively a physical
picture on the competition and coexistence between antiferromagnetic
order and superconducting orders in high temperature cuprate superconductors.Comment: 10 pages, 2 figure
Continuation power flow with the second order terms retained
2002-2003 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe
A Statistical Survey of Low‐Frequency Magnetic Fluctuations at Saturn
Low‐frequency waves are closely related to magnetospheric energy dissipation processes. The Cassini spacecraft explored Saturn's magnetosphere for over 13 years, until September 2017, covering a period of more than a complete solar cycle. Using this rich heritage dataset, we systematically investigated key physical parameters of low‐frequency waves in Saturn's magnetosphere, including their local time distribution and the dependence on solar activity. We found that the wave activity peaked in the near noon sector. For the nightside, the wave intensity also appeared to peak pre and post‐midnight. Due to the limited local time coverage for each solar phase, we were not able to draw a firm conclusion on the wave's dependence on solar activity. In general, the wave power showed a monotonically decreasing trend towards larger distances in nightside sectors especially during the declining phase, which implied that low‐frequency waves mainly originate from the relatively inner regions of the magnetosphere. On the dayside, stronger waves were mostly located at/within ∼25 Rs, near the magnetopause. The study shows a global picture of low‐frequency waves in Saturn's magnetosphere, providing important implications for how magnetospheric energy dissipates into Saturn's polar ionosphere and atmosphere
Evaluation of energetic particle parameters in the near-Earth magnetotail derived from flux asymmetry observations
Plasma Sheet Pressure Variations in the Near‐Earth Magnetotail During Substorm Growth Phase: THEMIS Observations
We investigate the plasma sheet pressure variations in the near‐Earth magnetotail (radius distance, R, from 7.5 RE to 12 RE and magnetic local time, MLT, from 18:00 to 06:00) during substorm growth phase with Time History of Events and Macroscale Interactions during Substorms (THEMIS) observations. It is found that, during the substorm growth phase, about 39.4% (76/193) of the selected events display a phenomenon of equatorial plasma pressure (Peq) decrease. The occurrence rates of Peq decrease cases are higher in the dawn (04:00 to 06:00) and dusk (18:00 to 20:00) flanks (> 50%) than in the midnight region (20:00 to 04:00, −16%). The mean value of Peq increase percentages at the end of substorm growth phase is the highest (~ 40%) in the premidnight MLT bin (22:00 to 00:00) and is almost unchanged in the dawn and dusk flanks. Further investigations show that 13.0% of the events have more than 10% of Peq decrease at the end of substorm growth phase comparing to the value before the growth phase, and ~ 28.0% of the events have small changes (< 10%), and ~ 59.0% events have a more than 10% increase. This study also reveals the importance of electron pressure (Pe) in the variation of Peq in the substorm growth phase. The Pe variations often account for more than 50% of the Peq changes, and the ratios of Pe to ion pressure often display large variations (~ 50%). Among the investigated events, during the growth phase, an enhanced equatorial plasma convection flow is observed, which diverges in the midnight tail region and propagates azimuthally toward the dayside magnetosphere with velocity of ~ 20 km/s. It is proposed that the Peq decreases in the near‐Earth plasma sheet during the substorm growth phase may be due to the transport of closed magnetic flux toward the dayside magnetosphere driven by dayside magnetopause reconnection. Both solar wind and ionospheric conductivity effects may influence the distributions of occurrence rates for Peq decrease events and the Peq increase percentages in the investigated region.Key PointsAbout 40% of the selected events in the near‐tail region display a phenomenon of equatorial plasma pressure decreaseAn enhanced equatorial convection with speed of ~ 20 km/s is observed in our cases during the substorm growth phaseStatistical studies for the distributions of Peq properties and electron pressure variations are performedPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141851/1/jgra53963.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141851/2/jgra53963_am.pd
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