Polypyrrole (PPy) is a promising candidate for supercapacitor electrode materials owing to its high electric conductivity and large specific capacitance. However, the poor cycling performance and the ...mechanical deformation of PPy remain to be challenges. Here, PPy/Ni
2
Ploaded graphene oxide (PPy/Ni
2
P/GO) is fabricated via a simple ball-milling process. The as-prepared PPy/Ni
2
P/GO composites exhibit a high specific capacitance of 741.5 F g
-1
at 1 A g
-1
, good rate capability (81.4% of capacitance at 10 A g
-1
), and long-term cycling stability (89.76% retention after 5000 cycles at 1 A g
-1
).When used in the asymmetric supercapacitor, the PPy/Ni
2
P/GO//AC (active carbon) device exhibits the energy density of 61 Wh kg
-1
at the power density of 849.8 W kg
-1
and excellent cycling performance (89.4% capacitance retention after 3000 cycles at 10 A g
-1
). The excellent electrochemical performance is owed to the high surface area and high hydrophilicity of the PPy/Ni
2
P/GO composites, coupled with good electron conductivity of the graphene oxide, which lead to reduced ion diffusion lengths and low charge transfer resistance. These results demonstrate that PPy/Ni
2
P/GO composites are promising as electrodes for supercapacitors.
Summary
A serious of CoFe hydrous oxide nanoparticles (Co1−zFezOxHy NP z = 0‐1) were synthesized by stirring CoCl2 and FeCl2 in aqueous KOH solutions for 0.5 hours, and the resulting nanoparticles ...are active electrocatalysts for water oxidation reaction (WOR) in alkaline solutions. The Co0.75Fe0.25OxHy NP, which are the most active electrocatalysts, have a layered double hydroxide (LDH) structure, with the average particle sizes about 16 nm. When using Ni foam as the substrate, the electrode with Co0.75Fe0.25OxHy NP as catalysts exhibited an overpotential of 284 mV for WOR in 1 M KOH at 10 mA cm−2. The Tafel slope was 43 mV dec−1, and the TOF was 1.30 s−1 at 350 mV overpotential (loading Co + Fe = 0.133 mg cm−2). The Co0.75Fe0.25OxHy NP are robust toward long‐term galvanostatic test and showed less than 2% dissolution in 10 hours. Preliminary kinetic study suggests that the presence of Fe in Co1−zFezOxHy NP alters the WOR mechanistic pathways. The increased number of electrochemically active sites endowed by the LDH structure and the electronic interactions between Co and Fe as suggested by XPS, both contribute to the enhanced WOR activity.
A simple co‐precipitation method was adopted to prepare a series of CoFe hydrous oxide nanoparticles in air at room temperature, with the most active nanoparticles exhibited an overpotential of 284 mV for water oxidation reaction in 1 M KOH at 10 mA cm−2. The catalysts can be separated as powders and can be applied to various substrates with desired loadings. The origins for enhanced water oxidation activity caused by the presence of Fe in the catalysts were investigated.
Although numerous global Last Glacial Maximum (gLGM) dating-based paleoclimatic and paleoglacial reconstructions exist for the Tibetan Plateau, no such study is available for the mountains to the ...Tibetan Plateaus east. Mount Taibai lies east of the Tibetan Plateau, and is known to have experienced glaciation during the Quaternary. In this study, optically stimulated luminescence (OSL) dating was employed to determine the ages of two lateral moraines in the Eryehai Valley on Mount Taibai. The ages obtained were 22.1 ± 1.7–18.7 ± 1.1 ka and 25.8 ± 1.8–24.3 ± 1.5 ka, constrain the timing of the gLGM glaciation in the study area. Using GlaRe and equilibrium-line altitude (ELA) calculations, these two toolboxes, based on a Geographic Information System (GIS), were used to reconstructed the extent of the study areas paleoglacial surface and the ∆ELA. The glacial coverage and ELA for the gLGM in the Eryehai Valley on Mount Taibai were 0.17 km3 and 3351.5 ± 5 m above sea level (asl), respectively. This gLGM ELA is lower than the modern theoretical ELA (4816.5 m asl) by 1465 ± 5 m. From the sporopollen records of the Zoigê Basin in the northwestern Mount Taibai, the precipitation during the gLGM period was equivalent to 60–80% of the present, combined with this record, ∆ELA-based models of the precipitation–temperature relationship (P-T) and the temperature lapse rate (LR) model at the ELA indicate that this area was 7.0 –9.4 °C colder during the gLGM. Combined with other paleoclimatic proxies, a decrease in temperature emerges as the primary driver of glaciation during the gLGM on Mount Taibai. Paleoclimatic reconstructions of paleoglaciers on the Tibetan Plateau and its adjacent mountains also indicate that a drop in temperatures was the principal driver of glacial advances in these regions during the gLGM. Regions affected by the East Asian Monsoon, the Indian Monsoon and the Westerlies would have experienced a greater cooling during the gLGM, while regions blocked by high mountains, and therefore less affected by monsoons and westerly winds, would have seen less cooling.
•Optically stimulated luminescence ages constrain the timing of the glaciation in Mount Taibai.•Glacier models are used to interpret the global Last Glacial Maximum climate.•The primary driver of glaciation is a decrease in temperature.•GLGM climate was 7.0–9.4 °C colder than today with precipitation being 60–80% of today.•The temperature decreased differently during the gLGM on the Tibetan Plateau and its adjacent mountains.
SnO
2
/Fe
2
O
3
composites with a novel heterojunction nanostructure are successfully prepared via a facile two-step hydrothermal method. Fe
2
O
3
nanoparticles with an average size of ~ 15 nm are ...found to attach onto the surface of SnO
2
nanosheets with the diameter about 300 nm. The reversible capacity, cycling stability, and rate performance of the as-prepared nanocomposites are significantly improved compared with SnO
2
or Fe
2
O
3
, which may be due to the synergistic effect between SnO
2
nanosheets and Fe
2
O
3
nanoparticles. Therefore, as an anode material for lithium-ion batteries, SnO
2
/Fe
2
O
3
nanocomposites deliver a high initial discharge and reversible capacity of 2174.9 mAh g
−1
and 1022 mAh g
−1
at the current density of 100 mA g
−1
and after 100 cycles, respectively. Even at the current density of 1000 mA g
−1
, the reversible capacity can still keep at 683 mAh g
−1
after 100 cycles, which might be a good candidate for high-performance lithium ion batteries.
Glacial landforms on Mount Taibai, the main peak of the Qinling Mountains, China, are investigated to improve understanding of Quaternary palaeoclimate evolution in this key region of China's ...geographical north and south junction. Cosmogenic radionuclide 10Be exposure dating and glacier-climate modeling are used to reconstruct glacier evolution during the last glaciation in the Eryehai Valley, on the slopes of Mount Taibai. Chronological results indicate that the earliest initiation of the Mount Taibai glaciation was earlier than the global Last Glacial Maximum (gLGM). The glacier subsequently advanced further reaching its greatest extent during the gLGM between ∼23.50 ka and 21.76 ka. After this time, the glacier receded rapidly, before disappearing completely between ∼17.9 ka and 17.7 ka. We also analyzed a compilation of 229 recalculated 10Be exposure ages from the mountain ranges on the eastern Tibetan Plateau (TP), as well as in the Jaggang Mountains on the south-central TP, and found that a few mountain ranges on the eastern TP experienced two distinct millennial-scale moraine building events during the gLGM. Using glacier-climate modeling, temperature was calculated to have fallen from between ∼9.0 and 9.4 °C during the gLGM, with precipitation being 60–80% of the present-day value. If precipitation during the rapid retreat of the glacier between ∼21.76 ka and 18.10 ka were to be consistent with present trends, then the temperature would have needed to increase by a total of ∼1.3 °C during this period, with a mean rate of increase of 0.4 °C/ka. Combining our findings with other paleoclimate proxies, we infer that the main reason that there was no further glacial advance after the gLGM on Mount Taibai was the lower altitude of its peak relative to the Equilibrium-line Altitude (ELA). Our results provide the paleoclimatic conditions of the last glaciation in this critical area of China's geographical north and south junction, and deepen the understanding of how the East Asian Summer Monsoon (EASM) influences glaciers on the TP.
•New CRN 10Be exposure age results elucidate the glacial evolutionary process since the last glaciation on Mount Taibai.•The earliest initiation of the Mount Taibai glaciation was earlier than the global Last Glacial Maximum.•The East Asian summer monsoonal was an important factor influencing the fluctuations in paleoglaciers of eastern China.•Some mountains on the eastern TP may have experienced two millennial-scale moraine building events during the gLGM.
Granites of the Mesozoic Era are widespread in South China, and many of them have been shaped into spectacular landscapes with high tourism development values. However, the controlling factors and ...evolution stages of these granite landscapes were poorly understood. In this study, the Hypsometric Integral curves (HIc), and Hypsometric Integral (HI) values of the Mount Wugong were extracted from digital elevation model data in a geographic information system environment. The relationships between the HCs, HI values, and factors including the tectonism, lithology and climate of the study area were analyzed to determine the evolution of granite landscapes evolution in the main scenic areas of the Mount Wugongshan. The HI values on the northwestern and southeastern slopes of the Mount Wugongshan range from 0.223 to 0.415 and 0.385 to 0.465, respectively; the HCs are mainly concave on the northwestern slopes and irregularly ‘S-shaped’ on the southeastern slopes. The main ridge of the granite geomorphic scenic area of the Mount Wugongshan, where the alpine meadow geomorphic landscape is located, is in the youthful stage of geomorphic evolution, the Mt. Jinding-Mt. Wanlong and Mt. Mingyue-Wentang scenic areas are in the old stage, and the Yangshimu scenic area is in the mature stage. Differences in watershed scale may be the main reason for the variabilities in geomorphic evolution in the area, while the regular development of tectonic phenomena is a key factor shaping the spatial variability in the watersheds on both sides of the main ridge.
We present geomorphological evidence for multiple glacial fluctuations during the Quaternary in the Taniantaweng Mountain, which is situated at the transition zone of the southeastern Qinghai-Tibet ...Plateau and the Yunnan-Guizhou Plateau. To reconstruct the history of glacial evolution during the Quaternary Glaciation, we present a ~13000 km2 geomorphologic map (1:440,000) for the Quaternary glaciations, as well as three electron spin resonance (ESR) ages and three optically stimulated luminescence (OSL) ages from the landforms. By integrating these with ages from previous studies, four major glacial advances are identified during marine oxygen isotope stages (MIS) 6, 3, 2 and 1. This glacial chronology is in reasonable agreement with existing glacial chronologies from other parts of the Hengduan Mountains and surrounding mountains. Glaciers had extended to the Yuqu River during the glacial maximum advance (MIS 6), but became successively more restricted from MIS 3 to MIS 1. The glacial distribution show that precipitation brought by the south Asian monsoon might play a primary role in driving glacial advances during the last glacial period in the southeastern Qinghai-Tibet Plateau.
By comparing with traditional L-shaped plate, to explore the effectiveness of new Pilon plate in the treatment of type C Pilon fracture.
A clinical data of 57 patients with type C Pilon fractures who ...met the selection criteria between May 2018 and January 2020 was analyzed retrospectively. Thirty-two patients were treated with new Pilon plate (trial group) and 25 patients with traditional L-shaped plate (control group). There was no significant difference in gender, age, cause of injury, fracture side and type, the interval between injury and operation between the two groups (
>0.05). The operation time and complications of the two groups were recorded. X-ray films were taken after operation to assess the quality of fracture reduction according to the Burwell-Charnley classification and fracture healing. Ankle function was evaluated according to Johner-Wruhs scoring standard and American Orthopaedic Foot and Ankle Society (AOFAS) score.
The operations of the two groups were completed successfully, and the ope
To explore the clinical effects of acupuncture with elongated needle on urinary retention after spinal cord injury.
A total of 66 patients with urinary retention after spinal cord injury were ...randomized into an elongated needle group (34 cases) and a filiform needle group (32 cases). In both of the groups, the routine orthopedic treatment and the bladder function training were adopted. Additionally, in the elongated needle group, the acupuncture at Zhibian (BL 54) and Shuidao (ST 28) was used with the elongated needle. In the filiform needle group, the acupuncture with filiform needle was used at Zhibian (BL 54) and Shuidao (ST 28). In both of the groups, acupuncture treatment was provided once every two days, for 2 months consecutively. Separately, before treatment and after 1, 2 month treatment, the residual urine volume, urodynamic parameters (bladder capacity, peak urinary flow rate and bladder pressure) and safety indicators were observed in the patients of the two groups. The clinical therapeutic effect
•·Amorphous cobalt–nickel phosphide films were electrodeposited on Ni foam under ambient conditions.•·The morphology of the deposited phosphide films varies with deposition time.•·The deposited films ...exhibited excellent hydrogen evolution and water oxidation activities in base.•·Overall water splitting was achieved at 410 mV overpotentials to reach 10 mA cm−2.
The synthesis of active and stable electrochemical water splitting catalysts using the earth-abundant elements is the key to reduce the cost of hydrogen production. In this paper, a series of cobalt–nickel phosphide films was electrodeposited on nickel foam substrates (Co-Ni-P), and the resulting electrodes are active in catalyzing both the hydrogen evolution reaction (HER) and water oxidation reaction (WOR) in alkaline solutions. The most active electrode towards HER required 92 mV overpotentials to reach − 10 mA cm−2 current densities, and the Tafel slope was 87.6 mV dec−1. Meanwhile, for WOR, the most active electrode needed 277 mV overpotentials to reach the 10 mA cm−2 WOR current densities, with the Tafel slope at 63.6 mV dec−1. The excellent performance is mainly owing to the high number of electrochemically active sites endowed by the unique morphology, and the possible electron interaction between Co and Ni. Water electrolysis carried out using the most active electrodes exhibited 1.64 V (410 mV overpotentials) to reach the current density of 10 mA cm−2, which suggests the Co-Ni-P prepared using this method is a promising candidate as electrodes to catalyze overall water splitting.
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