Dielectric capacitors with a high operating temperature applied in electric vehicles, aerospace and underground exploration require dielectric materials with high temperature resistance and high ...energy density. Polyimide (PI) turns out to be a potential dielectric material for capacitor applications at high temperatures. In this review, the key parameters related to high temperature resistance and energy storage characteristics were introduced and recent developments in all-organic PI dielectrics and PI-matrix dielectric nanocomposites were discussed. Synthetic strategies for new functional PI
via
modification at the molecular level together with the design engineering of nanofillers and multilayer structures of PIs were also analysed. Finally, a systematic summary of the current challenges and future developments for capacitor materials used at high temperatures were presented.
Dielectric capacitors with a high operating temperature applied in electric vehicles, aerospace and underground exploration require dielectric materials with high temperature resistance and high energy density.
Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease that was first recognised in China in 2009,1 and subsequently reported in South Korea and Japan.2,3 The disease is ...caused by the tick-borne phlebovirus, SFTS virus (STFSV)—a negative-sense single-stranded RNA virus.1,4 The increasing number of cases, extensive geographical expansion, and persistently high case fatality rate (CFR) of the disease are causing widespread concern in east Asia. To our knowledge, this is the largest study to analyse the risk factors for death from SFTS by use of clinical data (signs and symptoms), laboratory test results, and treatment regimens. ...on the basis of hospital records from over 2000 patients with SFTS and follow-up data on discharged patients, Li and colleagues found that the CFR for SFTS in Henan Province to be significantly higher than previously reported (16·2% vs 1·2–2·8%).6,10 Li and colleagues speculate that the low mortality of SFTS is due to local culture and economic conditions that prompt the families of dying patient's to discharge them before death, and hence they did not contribute to the number of fatal cases reported by the hospitals. iStock/moonnoon I declare no competing interests.
The outbreak of coronavirus disease 2019 (COVID-19) is spreading rapidly 1–8. On 31 January 2020, the World Health Organization declared COVID-19 a public health emergency of international concern. ...By 13 March 2020, COVID-19 had been confirmed in 127 countries, with 145 166 cases and 5428 deaths worldwide.
Neonates are susceptible to SARS-CoV-2 infection. The symptoms in neonates were milder and outcomes were less severe compared to adults. Intrauterine vertical transmission is not impossible but direct evidence is still lacking.
https://bit.ly/342jGK9
Herein, synthetic graphite materials with hierarchical pores and large specific surface area were successfully prepared by one-step impregnation with lignite as the carbon source, sulfuric acid (H
2
...SO
4
) as the oxidant, and phosphoric acid (H
3
PO
4
) as the activator. The microstructural characteristics of synthetic graphite were investigated
via
X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Moreover, the pore parameters were studied by nitrogen adsorption-desorption. The results showed that synthetic graphite had a perfect orderly layered structure with high graphitization degree and a well-developed multistage pore structure with pore sizes ranging from nanometer to micrometer. The specific surface area and pore volume were 415.29 m
2
g
−1
and 0.67 cm
3
g
−1
, respectively. The results of Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) showed that the impregnation pretreatment provided polar groups containing oxygen to the surfaces. These unique characteristics make synthetic graphite possess good adsorption capacity for dye pollutants (the adsorption rate of the methyl orange solution was 99.9% within 60 min at 50 °C, and the pH value of the solution was 3). The effects of temperature and pH value on the adsorption capacity were studied. The repeatability of the adsorption performance was also tested, and the adsorption rate was 84.6% of the initial adsorption rate after five cycles.
Herein, synthetic graphite materials with hierarchical pores and large specific surface area were prepared by one-step impregnation with lignite as the carbon source, H
2
SO
4
as the oxidant, and H
3
PO
4
as the activator.
In the latest version of the International Centre for Theoretical Physics' regional climate model, RegCM4, CLM was introduced as a new land surface scheme. The performance over China of RegCM4-CLM ...with different convection schemes is analyzed in this study, based on a series of short-term experiments. The model is driven by ERA-Interim data at a grid spacing of 25 km. The convection schemes employed are: Emanuel; Grell; Emanuel over land and Grell over ocean; Grell over land and Emanuel over ocean; and Tiedtke. The simulated mean surface air temperature and precipitation in December-February-January and June-July-August are compared against observation. In general, better performance of Emanuel is found both for temperature and precipitation, and in both seasons. Thus, the model physics of CLM and Emanuel for the land surface processes and convection, respectively, are recommended for further application of RegCM4 over the China region. The deficiencies that remain in the model are also outlined and discussed.
We revisit a classical graph-theoretic problem, the
single-source shortest-path
(SSSP) problem, in weighted unit-disk graphs. We first propose an exact (and deterministic) algorithm which solves the ...problem in
O
(
n
log
2
n
)
time using linear space, where
n
is the number of the vertices of the graph. This significantly improves the previous deterministic algorithm by Cabello and Jejčič CGTA’15 which uses
O
(
n
1
+
δ
)
time and
O
(
n
1
+
δ
)
space (for any constant
δ
>
0
) and the previous randomized algorithm by Kaplan et al. SODA’17 which uses
O
(
n
log
12
+
o
(
1
)
n
)
expected time and
O
(
n
log
3
n
)
space. More specifically, we show that if the 2D offline insertion-only (additively) weighted nearest-neighbor problem with
k
operations (i.e., insertions and queries) can be solved in
f
(
k
) time, then the SSSP problem in weighted unit-disk graphs can be solved in
O
(
n
log
n
+
f
(
n
)
)
time. Using the same framework with some new ideas, we also obtain a
(
1
+
ε
)
-approximate algorithm for the problem, using
O
(
n
log
n
+
n
log
2
(
1
/
ε
)
)
time and linear space. This improves the previous
(
1
+
ε
)
-approximate algorithm by Chan and Skrepetos SoCG’18 which uses
O
(
(
1
/
ε
)
2
n
log
n
)
time and
O
(
(
1
/
ε
)
2
n
)
space. More specifically, we show that if the 2D offline insertion-only weighted nearest-neighbor problem with
k
1
operations in which at most
k
2
operations are insertions can be solved in
f
(
k
1
,
k
2
)
time, then the
(
1
+
ε
)
-approximate SSSP problem in weighted unit-disk graphs can be solved in
O
(
n
log
n
+
f
(
n
,
O
(
ε
-
2
)
)
)
time. Because of the
Ω
(
n
log
n
)
-time lower bound of the problem (even when approximation is allowed), both of our algorithms are almost optimal.
Printed flexible photodetectors based on 2D inorganic perovskites with atomic thickness show excellent photosensing with fast rise and decay response times. As‐synthesized nanosheets can easily be ...dispersed in various solvents, leading to large‐area, crack‐free, low‐roughness, flexible films after printing. This study demonstrates that all‐inorganic perovskite CsPbX3 nanosheets as a new class of 2D semiconductors have huge potential for flexible optoelectronic applications.
The authors review recent advances in the development of coupled Regional Earth System Models (RESMs), a field that is still in its early stages. To date, coupled regional atmosphere-ocean-sea ice, ...atmosphere-aerosol and atmosphere-biosphere models have been developed, but they have been applied only to limited regional settings. Much more work is thus needed to assess their transferability to a wide range of settings. Future challenges in regional climate modeling are identified, including the development of fully coupled RESMs encompassing not only atmosphere, ocean, cryosphere, biosphere, chemosphere, but also the human component in a fully interactive way.
The first thermally activated delayed fluorescence (TADF) emitter and organic light-emitting diodes (OLEDs) in the near-infrared (NIR) II region (
λ
EL,max
= 1010 nm) were realized
via
intermolecular ...charge-transfer aggregates. This work provides a promising strategy for achieving TADF in the NIR-II region.
The first thermally activated delayed fluorescence emitter and organic light-emitting diodes in the near-infrared II region were realized
via
intermolecular charge-transfer aggregates.
Severe fever with thrombocytopenia syndrome (SFTS) is an emerging hemorrhagic fever in East Asia caused by SFTS virus (SFTSV), a newly discovered phlebovirus. The Haemaphysalis longicornis tick has ...been suspected to be the vector of SFTSV. To determine whether SFTSV can be transmitted among ticks, from ticks to animals, and from animals to ticks, we conducted transmission studies between developmental stages of H. longicornis ticks and between ticks and mice. Using reverse transcription PCR, we also analyzed the prevalence of SFTSV infection among H. longicornis ticks collected from vegetation in Shandong Province, China. Our results showed a low prevalence of SFTSV among collected ticks (0.2%, 8/3,300 ticks), and we showed that ticks fed on SFTSV-infected mice could acquire the virus and transstadially and transovarially transmit it to other developmental stages of ticks. Furthermore, SFTSV-infected ticks could transmit the virus to mice during feeding. Our findings indicate ticks could serve as a vector and reservoir of SFTSV.
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