20 research outputs found
Regional Geological Survey of Hanggai, Xianxia and Chuancun, Zhejiang Province in China
This Open Access book introduces readers to the regional geology of Hanggai, Xianxia and Chuancun, the area between China's northern Zhejiang Province and southern Anhui Province and explores the strata, magmatic rocks and tectonic structures in 1:50,000 scale geological maps. Based on studies of multiple stratigraphic divisions, the standard stratigraphic section of the upper Ordovician Hirnantian in the lower Yangtze region is established, revealing for the first time numerous “Burgess Shale-type” sponge fossils in Hirnantian strata and identifying 10 grapholite fossil belts and various fossil categories, including chitin, trilobites, gastropods, brachiopods, and cephalopods. Moreover, the book identifies for the first time Late Ordovician volcanic events in northern Zhejiang province. The work represents a major contribution to research on Paleozoic strata in the Lower Yangtze region, and sheds new light on understanding the Hirnantian glacial event and biological extinction event in South China by providing a high-precision time scale. In addition, the book opens an important avenue for future research on sponge evolution after the Cambrian life explosion. As such, it offers a unique and valuable asset for researchers and graduate students alike
AC impedance of A4C60 fullerides under pressure
Three A4C60 compounds, with A = Li, Na and K, have been studied by impedance spectroscopy between 100 K and 293 K at pressures up to 2 GPa. The results are in very good agreement with earlier DC resistance studies and with data from the literature. For all three materials the measured conductivity can be fitted by a sum of at least two Arrhenius terms. The band gaps derived from the resistance data, 0.3 eV for Na4C60 and 0.5 eV for K4C60, are in excellent agreement with data measured by other methods. For Li4C60, our results disagree with a recent suggestion that the conductivity is dominated by ionic conduction. Although a certain ionic component probably exists we suggest that electronic transport dominates in our samples at and below room temperature because the derived “activation energy” decreases under pressure, the derived “activation volume” is negative, and we observe neither a significant electrode blocking capacitance nor any significant metal transport under DC conditions
AC impedance of A4C60 fullerides under pressure
Three A4C60 compounds, with A = Li, Na and K, have been studied by impedance spectroscopy between 100 K and 293 K at pressures up to 2 GPa. The results are in very good agreement with earlier DC resistance studies and with data from the literature. For all three materials the measured conductivity can be fitted by a sum of at least two Arrhenius terms. The band gaps derived from the resistance data, 0.3 eV for Na4C60 and 0.5 eV for K4C60, are in excellent agreement with data measured by other methods. For Li4C60, our results disagree with a recent suggestion that the conductivity is dominated by ionic conduction. Although a certain ionic component probably exists we suggest that electronic transport dominates in our samples at and below room temperature because the derived “activation energy” decreases under pressure, the derived “activation volume” is negative, and we observe neither a significant electrode blocking capacitance nor any significant metal transport under DC conditions
Regional Geological Survey of Hanggai, Xianxia and Chuancun, Zhejiang Province in China
This Open Access book introduces readers to the regional geology of Hanggai, Xianxia and Chuancun, the area between China's northern Zhejiang Province and southern Anhui Province and explores the strata, magmatic rocks and tectonic structures in 1:50,000 scale geological maps. Based on studies of multiple stratigraphic divisions, the standard stratigraphic section of the upper Ordovician Hirnantian in the lower Yangtze region is established, revealing for the first time numerous “Burgess Shale-type” sponge fossils in Hirnantian strata and identifying 10 grapholite fossil belts and various fossil categories, including chitin, trilobites, gastropods, brachiopods, and cephalopods. Moreover, the book identifies for the first time Late Ordovician volcanic events in northern Zhejiang province. The work represents a major contribution to research on Paleozoic strata in the Lower Yangtze region, and sheds new light on understanding the Hirnantian glacial event and biological extinction event in South China by providing a high-precision time scale. In addition, the book opens an important avenue for future research on sponge evolution after the Cambrian life explosion. As such, it offers a unique and valuable asset for researchers and graduate students alike
Power Batteries Health Monitoring: A Magnetic Imaging Method Based on Magnetoelectric Sensors
With the popularity of electric vehicles, the ever-increasing demand for high-capacity batteries highlights the need for monitoring the health status of batteries. In this article, we proposed a magnetic imaging technique (MIT) to investigate the health status of power batteries nondestructively. This technique is based on a magnetic sensor array, which consists of a 16-channel high-performance magnetoelectric sensor, and the noise equivalent magnetic induction (NEB) of each channel reaches 3–5 pT/Hz1/2@10 Hz. The distribution of the magnetic field is imaged by scanning the magnetic field variation of different positions on the surface. Therefore, the areas of magnetic anomalies are identified by distinguishing different magnetic field abnormal results. and it may be possible to classify the battery failure, so as to put forward suggestions on the use of the battery. This magnetic imaging method expands the application field of this high-performance magnetoelectric sensor and contributes to the battery’s safety monitoring. Meanwhile, it may also act as an important role in other nondestructive testing fields
Six-year change in cataract surgical coverage and postoperative visual outcomes in rural southern China: The Yangxi Eye Study
Direct Conversion of Graphene Aerogel into Low-Density Diamond Aerogel Composed of Ultrasmall Nanocrystals
Diamond aerogel,
a special kind of carbon aerogel made by sp<sup>3</sup> carbon atoms,
has been attracting intensive research interest
due to its potential applications since it is first synthesized by
the conversion of amorphous carbon. Despite of many expectations in
diamond aerogel, the study on its synthesis is still not adequate
compared with other carbon aerogel. Here we report the synthesis of
diamond aerogel by laser heating graphene aerogel (GA) under high
pressure in a diamond anvil cell. The results suggest that the density
and microstructure of GA, as well as the heating duration obviously
affect the diamond aerogel growth. When heating GA with lower laser
power, we also observe a transparent carbon phase in experiment, which
transforms into graphite and amorphous carbon upon decompression.
These results present new insights into our understanding on the transformation
from ultralow density carbon to sp<sup>3</sup> carbon under high pressure
and high temperature. It is possible to tune the microstructures of
diamond aerogel by controlling the synthesis of GA precursors
Increasing Interlayer Coupling Prevented the Deformation in Compressed Multilayer WSe<sub>2</sub>
High-pressure investigations
on transition-metal dichalcogenides
(TMD) have been considered as an efficient way to investigate their
unique crystalline and electronic properties. Here we studied the
vibrational behaviors of pressurized multilayer WSe<sub>2</sub> with
two (2TL) to six layers (6TL) by Raman spectroscopy. The intralayer
and interlayer vibrations of WSe<sub>2</sub> all show a monotonous
blue shift without any discontinuity. Due to the strong interlayer
coupling interactions, no structural transition occurs, but nondegeneration
splitting of shear mode vibrations coming from pressure-induced in-plane
deformation is observed. As the interlayer coupling increases in thicker
WSe<sub>2</sub>, the in-plane deformation is suppressed and takes
place at higher pressure. The monotonous increase of force constants
and elastic constants suggested a stable structure of WSe<sub>2</sub> within our studied pressure range