检索结果-南通市图书馆

Journal of Energy Chemistry 2016年第5期25卷 761-768页

作者： V.Simone A.Boulineau A.de Geyer D.Rouchon L.Simonin *** Univ. Grenoble Alpes CEA LITEN CEA INAC CEA LETI

Cellulose, the most abundant organic polymer on Earth, is a sustainable source of carbon to use as a negative electrode for sodium ion batteries. Here, hard carbons(HC) prepared by cellulose pyrolysis were investigated with varying pyrolysis temperature from 700 °C to 1600 °C. Characterisation methods such as Small Angle X-ray Scattering(SAXS) measurements and N2adsorption were performed to analyse porosity differences between the samples. The graphene sheet arrangements were observed by transmission electron microscopy(TEM): an ordering of the graphene sheets is observed at temperatures above 1150 °C and small crystalline domains appear over 1400 °C. As the graphene sheets start to align, the BET surface area decreases and the micropore size increases. To correlate hard carbon structures and electrochemical performances, different tests in Na//HC cells with 1 M NaPF6ethylene carbonate/dimethyl carbonate(EC/DMC) were performed. Samples pyrolysed from 1300 °C to 1600 °C showed a 300 m Ah/g reversible capacity at C/10 rate(where C = 372 mA/g) with an excellent stability in cycling and a very good initial Coulombic efficiency of up to 84%. Furthermore, hard carbons showed an excellent rate capability where sodium extraction rate varies from C/10 to 5C. At 5C more than 80% of reversible capacity remains stable for hard carbons synthesized from 1000 °C to 1600 °C.

关键词： Sodium ion battery Anode Hard carbon Structure

Lights for epilepsy:can photobiomodulation reduce seizures and offer neuroprotection?

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2023年第7期18卷 1423-1426页

作者： Napoleon Torres-Martinez Stephan Chabardes John Mitrofanis University of Grenoble Alpes FDD and CEA-LETIClinatecGrenobleFrance

Epilepsy is synonymous with individuals suffering repeated“fits”or seizures.The seizures are triggered by bursts of abnormal neuronal activity,across either the cerebral cortex and/or the hippocampus.In addition,the seizure sites are characterized by considerable neuronal death.Although the factors that generate this abnormal activity and death are not entirely clear,recent evidence indicates that mitochondrial dysfunction plays a central role.Current treatment options include drug therapy,which aims to suppress the abnormal neuronal activity,or surgical intervention,which involves the removal of the brain region generating the seizure activity.However,~30%of patients are unresponsive to the drugs,while the surgery option is invasive and has a morbidity risk.Hence,there is a need for the development of an effective non-pharmacological and non-invasive treatment for this disorder,one that has few side effects.In this review,we consider the effectiveness of a potential new treatment for epilepsy,known as photobiomodulation,the use of red to near-infrared light on body tissues.Recent studies in animal models have shown that photobiomodulation reduces seizure-like activity and improves neuronal survival.Further,it has an excellent safety record,with little or no evidence of side effects,and it is non-invasive.Taken all together,this treatment appears to be an ideal treatment option for patients suffering from epilepsy,which is certainly worthy of further consideration.

关键词： cell death gliosis inflammation infrared mitochondria non-pharmacological red seizure

A Colocalized Scheme for Three-Temperature Grey Diffusion Radiation Hydrodynamics

在线全文

学校读者我要写书评

暂无评论

Communications in Computational Physics 2022年第1期31卷 293-330页

作者： R.Chauvin S.Guisset B.Manach-Perennou L.Martaud CEA DAMDIFF-91297 ArpajonFrance

A positivity-preserving, conservative and entropic numerical scheme is presented for the three-temperature grey diffusion radiation hydrodynamics model. Moreprecisely, the dissipation matrices of the colocalized semi-Lagrangian scheme are de-fined in order to enforce the entropy production on each species (electron or ion) proportionally to its mass as prescribed in [34]. A reformulation of the model is then considered to enable the derivation of a robust convex combination based scheme. Thisyields the positivity-preserving property at each sub-iteration of the algorithm whilethe total energy conservation is reached at convergence. Numerous pure hydrodynamics and radiation hydrodynamics test cases are carried out to assess the accuracy of themethod. The question of the stability of the scheme is also addressed. It is observedthat the present numerical method is particularly robust.

关键词： Colocalized Lagrangian scheme radiation hydrodynamics grey diffusion discrete entropy production plasma physics simulations

flash-lamp pumping;high-power laser;laser cooling;neodymium glass;wavefront error

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

High Power Laser Science and Engineering 2024年第1期12卷 24-29页

作者： Pierre-Marie Dalbies Sandy Cavaro Edouard Bordenave Nathalie Blanchot Julien G.Moreau Jérôme Neauport CEA CESTA Le BarpFrance

Mid-spatial frequency wavefront deformation can be deleterious for the operation of high-energy laser systems. When fluid cooled high-repetition-rate amplifiers are used, the coolant flow is likely to induce such detrimental mid-spatial frequency wavefront deformations. Here, we describe the design and performance of a 90 mm × 90 mm aperture, liquid-cooled Nd:phosphate split-slab laser amplifier pumped by flash-lamps. The performance of the system is evaluated in terms of wavefront aberration and gain at repetition rates down to 1 shot per minute. The results show that this single cooled split-slab system exhibits low wavefront distortions in the medium to large period range, compatible with a focus on target, and despite the use of liquid coolant traversed by both pump and amplified wavelengths. This makes it a potential candidate for applications in large high-energy laser facilities.

关键词： flash-lamp pumping high-power laser laser cooling neodymium glass wavefront error

High-frequency structure design and RF stability analysis of a 4-vane radio frequency quadrupole with pi-mode stabilizer loops

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2022年第3期33卷 113-125页

作者： Xiao-Wen Zhu Claude Marchand Olivier Piquet Michel Desmons IRFU CEAUniversite´Paris-Saclay91191 Gif-sur-YvetteFrance

Compact accelerator-based neutron source facilities are garnering attention and play an important and expanding role in material and engineering sciences,as well as in neutron science education and training.Neutrons are produced by bombarding a low-energy proton beam onto a beryllium or lithium target.In such an acceleratorbased neutron source,a radio frequency quadrupole(RFQ)is usually utilized to accelerate a high-intensity proton beam to a few MeV.This study mainly covers the highfrequency structure design optimizations of a 4-vane RFQ with pi-mode stabilizer loops(PISLs)and its RF stability analysis.A 176 MHz RFQ accelerator is designed to operate at a 10%duty factor and could accelerate an80 mA proton beam from 65 keV to 2.5 MeV within a length of 5.3 m.The adoption of PISLs ensures high RF stability,eases the operation of the accelerator,and implies less stringent alignment and machining tolerances.

关键词： Accelerator-based neutron source 4-vane RFQ accelerator Pi-mode stabilizer loops Perturbative analysis Electromagnetic design Multipacting simulation

Multi-dimensional Simulation of Phase Change by a 0D-2D Model Coupling via Stefan Condition

在线全文

学校读者我要写书评

暂无评论

Communications on Applied Mathematics and Computation 2023年第2期5卷 853-884页

作者： Adrien Drouillet Romain Le Tellier Raphaël Loubère Mathieu Peybernes Louis Viot Institut de Mathématiques de Bordeaux Universitéde Bordeaux33405 Talence CedexFrance CEA-DES-IRESNE-DTN CEA Cadarache13108 Saint Paul-lez-DuranceFrance

Considering phase changes associated with a high-temperature molten material cooled down from the outside,this work presents an improvement of the modelling and the numerical simulation of such processes for an application pertaining to the safety of light water nuclear reactors.Postulating a core meltdown accident,the behaviour of the core melt(aka corium)into a steel vessel is of tremendous importance when evaluating the vessel integrity.Evaluating correctly the heat fluxes requires the numerical simulation of the interaction between the liquid material and its solid counterpart which forms during the solidification process,but also may melt back.To simulate this configuration,encoun-tered in various industrial applications,one considers a bi-phase model constituted by a liquid phase in contact and interaction with its solid phase.The liquid phase may solidify in presence of low energetic source,while the solid phase may melt due to an intense heat flux from the high-temperature liquid.In the frame of the in-house legacy code,several simplifying assumptions(0D multi-layer discretization,instantaneous heat transfer via a quadratic temperature profile in solids)are made for the modelling of such phase changes.In the present work,these shortcomings are illustrated and further overcome by solving a 2D heat conduction model in the solid by a mixed Raviart-Thomas finite element method coupled to the liquid phase due to heat and mass exchanges through Stefan condition.The liquid phase is modeled with a 0D multi-layer approach.The 0D-liquid and 2D-solid mod-els are coupled by a Stefan like phase change interface model.Several sanity checks are performed to assess the validity of the approach on 1D and 2D academical configurations for which exact or reference solutions are available.Then more advanced situations(genu-ine multi-dimensional phase changes and an"industrial-like scenario")are simulated to verify the appropriate behavior of the obtained coupled simulation scheme.

关键词： Simulation of phase change Fusion Solidification 0D multi-layer model 2D heat conduction model Model coupling

GPS observation in Sichuan-Yunnan and its vicinity before and after the Wenchuan earthquake in a decade

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Geodesy and Geodynamics 2021年第1期12卷 43-47页

作者： Peng Jia Xi Zhang Wenquan Zhuang Fengyun Jiang Second Monitoring and Application Center CEAChina

Based on the horizontal velocity data observed by GPS during 2004-2007,2007-2009,and 2011-2017 before,during,and after the Wenchuan earthquake in Sichuan-Yunnan and its vicinity,we analyze evolution features of the tectonic deformation caused by crustal movement in main active fault belts,and its possible influence.We conclude:the Wenchuan earthquake area showed obvious co-seismic thrust and dextral deformation from 2007 to 2009.The earthquake,to a certain extent,promoted tectonic movements on the Gansu-Sichuan boundary,Western Qinling fault zone,Anninghe-Zemuhe fault zone,and southern Xianshuihe fault zone.The vectors and strain filed acquired by GPS during Lushan and Jiuzhaigou earthquakes period may indicate that the southwest segment in the Longmenshan fault zone still has the possibility of larger earthquakes.

关键词： Sichuan-Yunnan and its vicinity The Wenchuan earthquake GPS Tectonic deformation Jiuzhaigou

Mercury indicating inflow zones and ruptures along the Wenchuan Ms 8.0 earthquake fault

在线全文

学校读者我要写书评

暂无评论

Chinese Journal Of Geochemistry 2015年第2期34卷 201-207页

作者： Yang Duoxing Zhang Lei Liu Yaowei Ren Hongwei Xie Furen Chen Gangcai Key Laboratory of Crustal Dynamics Institute of Crustal DynamicsCEA Institute of Geophysics CEA Chongqing Academy of Environmental Sciences

During the Wenchuan Fault Scientific Drilling Project,we determined the values of total mercury(HgT)and gaseous elemental mercury(GEM) from drilled cores and drilling mud,respectively.Geochemical analysis shows HgT values ranging from 0.24 to 6.45 ng/g for the Penguan complex and from 2.90 to 137.54 ng/g for T3 sediment.The average levels of HgT for the Penguan complex and T3 sediments are 1.81 ± 0.26 ng/g and23.96 ± 4.80 ng/g,respectively.Major anomalous peaks of HgT appear at depth of 614,731,993 and 1,107 m,which correspond to the long-term high seismic activity during crustal deformation in response to tectonic stresses.Gaseous elemental mercury dissolved in drilling mud was also analyzed.We found fluid inflow zones with high GEM at depths of 590-750 m,suggesting that fluid-filled ruptures exist in the LMS fault zone.It indicates that mercury provides geochemical evidence for inflow zones and ruptures/fault zones in the Wenchuan Ms 8.0 earthquake fault.

关键词：地震断层断裂带汶川水星明流科学钻探工程地球化学分析钻井泥浆

Analysis of Dynamic Characteristics of Crustal Horizontal Deformation in the South Segment of Longmenshan Fault Zone Revealed by GPS Data after the Wenchuan Earthquake

在线全文

学校读者我要写书评

暂无评论

Earthquake Research in China 2016年第1期30卷 43-56页

作者： Xiong Xiaohui Jiang Zaisen Wu Yanqiang Wang Qixin Li Shengle Key Laboratory of Earthquake Geodesy Institute of SeismologyCEA Institute of Earthquake Science CEA First Crust Deformation Monitoring and Application Center CEA Institute of Geology CEA

In order to obtain deformation parameters in the south segment of Longmenshan fault zone,Euler datum transformation and the least square collocation for data interpolation and smoothing are used to process GPS displacement time series data in the south segment of Longmenshan fault zone,and the rigid and elastic-plastic block motion model is used to calculate the strain parameters in each subarea. Conjoint analysis of displacement,velocity of each station and strain parameters of each subarea reveals that the influence of the Wenchuan earthquake on the south segment of Longmenshan fault zone increases from southeast to northwest,causing a highest deformation rate 6 times the background value and heightening the influence of the hidden faults on the difference of the earth surface along its two sides,which leads to the seismic risk of the southern segment increasing from north to south. The comparison of seismic risk among subareas based on the tectonic and seismicity background indicates that the most dangerous area is on the southeast of Longmenshan faults,and the background strain accumulation and the promoting effect of the Wenchuan earthquake advanced the occurrence of Lushan earthquake and the sinistral strike-slip on the rupture plane. The Wenchuan earthquake also caused a slight two-year long continuous strain release in the south segment of Xianshuihe fault,but the influence is far less than the effect of the compressive strain caused by the Sichuan-Yunnan block.

关键词：龙门山断裂带地震后 GPS 汶川数据显示水平形变动态特征地壳

Crustal Deformation Derived from GPS in the Chinese Mainland from 1991-2004

在线全文

学校读者我要写书评

暂无评论

Earthquake Research in China 2015年第2期29卷 225-236页

作者： Cao Jianling Wang Hui Wu Yanqiang Liu Xiaoxia Zhang Jing Key Laboratory of Earthquake Prediction CEA First Crust Monitoring and Application Center CEA Institute of Earthquake Science CEA

Based on GPS data from 1991- 2004 and the least-squares collocation method,we analyze the crustal deformation in the Chinese mainland. The results show that the first-order crustal deformation is unchanged in different periods in the Chinese mainland,which reflects the background of regional tectonic activity. The strain rate is much higher in Western China,especially in the Qinghai-Tibetan Plateau and Sichuan-Yunnan area. The variations in different periods are related with seismicity of strong earthquakes during the same time. The GPS data after 2004 shows the post-seismic deformation of the 2001 Kunlun Mountains M S8. 1 earthquake.

关键词： GPS数据中国大陆地壳形变最小二乘配置法区域构造活动西部地区四川地区强震活动