摘要：
LiNi_(0.8)Co_(0.15)Al_(0.05)O_(2)@Cr_(2)O_(5)composite electrode combines the high rate-capability characteristics of NCA with the stability of Cr_(2)O_(5),playing a synergistic role in improving the cyclic stability,initial discharge capacity and the security of low cut-off voltage(2.0 V).When the mass ratio of Cr_(2)O_(5)in NCA is 45%(mass),the capacity retention rate increases from 58.5% without Cr_(2)O_(5)to 69.3% in the range of 2.0-4.3 V.The initial discharge capacity of NCA@Cr_(2)O_(5)composite material is 211.4 mA·h·g^(-1),its first coulombic efficiency is 94.2%,and the charging capacity remains approximately constant when mixed with 15%(mass)Cr_(2)O_(5).The reason for the improvement of the initial charge-discharge efficiency(ICDE)was explained.Impedance and cyclic voltammetry analysis reveal more detailed reasons of the observed improvements.Compared with NCA cathode material,the NCA@Cr_(2)O_(5)composite material can provide not only additional stable sites and channels for Li^(+)insertion/extraction to make up for the loss of active Li^(+)sites and prevent the accumulation of Li+in the circulation process,but also protect the NCA electrode from the corrosion of the electrolyte decomposition by the Cr_(2)O_(5)nanoparticles adhering to NCA interface.
摘要：
In recent years,the semi-airborne transient electromagnetic method(SATEM)has been rapidly developed in China.Based on the theoretical development of the long grounding wire source transient electromagnetic method,the unmanned aerial vehicle is equipped with the receiving coil to collect the electromagnetic response data at high altitude,making the TEM no longer affected by the terrain and greatly improving the actual working efficiency.However,its flight altitude has not been concerned for a long time.It is generally believed that the change of flight altitude only affects the amplitude of the received response.However,under special circumstances,the electromagnetic response data received at different flight altitudes in the near and far regions may lose the characteristic information of the target geological body.This paper simulates the low resistance thin layer model and analyzes the electromagnetic responses of different receiving heights under different transceiver distances.The results show that in the near area,when the flight altitude is higher than 30 meters or more,the received electromagnetic response will lose the information of the shallow lowresistance thin layer,while in the far area,the change of flight altitude has no obvious influence on the characteristic electromagnetic response information of the received geological body.
摘要：
The pathophysiology of irritable bowel syndrome(IBS)is not completely understood.However,several factors are known to play a role in pathophysiology of IBS such as genetics,diet,gut microbiota,gut endocrine cells,stress and low-grade inflammation.Understanding the pathophysiology of IBS may open the way for new treatment approaches.Low density of intestinal stem cells and low differentiation toward enteroendocrine cells has been reported recently in patients with IBS.These abnormalities are believed to be the cause of the low density of enteroendocrine cells seen in patients with IBS.Enteroendocrine cells regulate gastrointestinal motility,secretion,absorption and visceral sensitivity.Gastrointestinal dysmotility,abnormal absorption/secretion and visceral hypersensitivity are all seen in patients with IBS and haven been attributed to the low density the intestinal enteroendocrine cells in these patients.The present review conducted a literature search in Medline(Pub Med)covering the last ten years until November 2019,where articles in English were included.Articles about the intestinal stem cells and their possible role in the pathophysiology of IBS are discussed in the present review.The present review discusses the assumption that intestinal stem cells play a central role in the pathophysiology of IBS and that the other factors known to contribute to the pathophysiology of IBS such as genetics,diet gut microbiota,stress,and lowgrade inflammation exert their effects through affecting the intestinal stem cells.It reports further the data that support this assumption on genetics,diet,gut microbiota,stress with depletion of glutamine,and inflammation.
摘要：
Low back pain has become more prevalent in recent years,causing enormous economic burden for society and government.Common therapies used in clinics including conservative treatment and surgery can only relieve pain.Subsequent cell-based treatment such as mesenchymal stem cell transplantation poses problems such as short duration of therapeutic effect and tumorigenesis.Recently,the discovery and identification of stem cell niche and stem/progenitor cells in intervertebral disc bring increased attention to endogenous repair strategy.Therefore,we review the studies involving endogenous repair strategy and present the characteristics and current status of this treatment.Meanwhile,we also discuss the strategy and perspective of endogenous repair strategy in future.
摘要：
The Double Take column looks at a single topic from an African and Chinese perspective.This month we discuss if minors should be allowed to use mobile phones.
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