全文获取类型
收费全文 | 234篇 |
免费 | 50篇 |
国内免费 | 8篇 |
专业分类
化学 | 96篇 |
晶体学 | 3篇 |
力学 | 1篇 |
物理学 | 16篇 |
无线电 | 176篇 |
出版年
2024年 | 5篇 |
2023年 | 56篇 |
2022年 | 8篇 |
2021年 | 42篇 |
2020年 | 36篇 |
2019年 | 14篇 |
2018年 | 13篇 |
2017年 | 14篇 |
2016年 | 12篇 |
2015年 | 9篇 |
2014年 | 8篇 |
2013年 | 10篇 |
2012年 | 6篇 |
2011年 | 7篇 |
2010年 | 5篇 |
2009年 | 11篇 |
2008年 | 6篇 |
2007年 | 3篇 |
2006年 | 6篇 |
2005年 | 3篇 |
2004年 | 1篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1989年 | 4篇 |
1974年 | 1篇 |
排序方式: 共有292条查询结果,搜索用时 25 毫秒
51.
Batteries: A Flexible 3D Multifunctional MgO‐Decorated Carbon Foam@CNTs Hybrid as Self‐Supported Cathode for High‐Performance Lithium‐Sulfur Batteries (Adv. Funct. Mater. 37/2017)
下载免费PDF全文
![点击此处可从《Advanced functional materials》网站下载免费的PDF全文](/ch/ext_images/free.gif)
52.
Improved Performance in FeF2 Conversion Cathodes through Use of a Conductive 3D Scaffold and Al2O3 ALD Coating
下载免费PDF全文
![点击此处可从《Advanced functional materials》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Sanghyeon Kim Jinyun Liu Junjie Wang Shen J. Dillon Paul V. Braun 《Advanced functional materials》2017,27(35)
FeF2 is considered a promising conversion compound for the positive electrode in lithium‐ion batteries due to its high thermodynamic reduction potential (2.66 V vs Li/Li+) and high theoretical specific capacity (571 mA h g?1). However, the sluggish reaction kinetics and rapid capacity decay caused by side reactions during cycling limit its practical application. Here, the fabrication of Ni‐supported 3D Al2O3‐coated FeF2 electrodes is presented, and it is shown that these structured electrodes significantly overcome these limitations. The electrodes are prepared by iron electrodeposition on a Ni support, followed by a facile fluorination process and Al2O3 coating by atomic layer deposition. The 3D FeF2 electrode delivers an initial discharge capacity of 380 mA h g?1 at a current density of 200 mA g?1 at room temperature. The 3D scaffold improves the reaction kinetics and enables a high specific capacity by providing an efficient electron pathway to the insulating FeF2 and short Li diffusion lengths. The Al2O3 coating significantly improves the cycle life, probably by preventing side reactions through limiting direct electrode–electrolyte contact. The fabrication method presented here can also be applied for synthesis of other metal fluoride materials on different 3D conductive templates. 相似文献
53.
J.A. Alonso M.J. Martínez-Lope A. Aguadero L. Daza 《Progress in Solid State Chemistry》2008,36(1-2):134-150
Neutron diffraction is a powerful tool for the characterization of materials and, particularly, oxides. Oxide materials find applications in solid oxide fuel cells (SOFCs) as solid electrolytes as well as anode and cathode materials. As a structural probe, neutrons are specially suitable for the crystallographic study of oxides, given the comparable scattering factors of O and other heavier elements, allowing its precise localization in the crystal structure. Many problems can be addressed by neutrons, related to the octahedral tilting in perovskites, phase transitions, order–disorder phenomena, presence of anionic vacancies, etc. Neutrons make possible an accurate determination of the thermal factors and provide a visualization of the diffusion paths in ionic conductors. Neutrons allow the localization of light atoms such as hydrogen, and make possible the distinction between neighbouring elements, typically Fe and Mn. In this work we will describe some recent applications of this technique in the field of solid electrolytes and electrode materials, including some examples from our group. 相似文献
54.
Results of calculating the major overall characteristics of both an individual cathode and the whole hydrogen-oxygen (air) fuel cell with Nafion and platinum are shown. The effect of varying the parameters of both the active layer and the polymeric-electrolyte membrane on the overall characteristics of such a fuel cell is analyzed. The mechanisms of operation of active layers of hydrophobized cathodes and cathodes containing Nafion are compared. These two electrode types demonstrate a qualitative difference in the current generation mechanisms. As a result, the current in cathodes with Nafion increases more actively with the increase in over-potential (in proportion with exp [η0/2], where η0 is the cathodic overpotential) as compared with the case of hydrophobized cathodes (here the current ~ exp[η0/4]). This explains the fact that a fuel cell with Nafion demonstrates so high power characteristics as compared with a fuel cell with hydrophobized electrodes and liquid electrolyte. 相似文献
55.
G. N. Mazo S. N. Savvin A. M. Abakumov J. Hadermann Yu. A. Dobrovol’skii L. S. Leonova 《Russian Journal of Electrochemistry》2007,43(4):436-442
Samples of lanthanum-strontium cuprate LaSrCuO3.61 are synthesized by a solid-phase method at 1473 K, in air. Electron diffraction patterns reveal low-intensity satellites whose position is described in the reciprocal space by the (3 + 2)-dimensional space group I4/mmm(αα0, α-α0)00mg. Using a five-layer cell LaSrCuO4-δ|YSZ|LaSrCuO4-δ|YSZ|LaCuO4-δ prepared by isostatic hot pressing, the ionic component of conductivity of LaSrCuO4-δ is determined (σ1179 K = 3.8 × 10?3 S cm?1), which is commensurate with other mixed conductors based on complex oxides of cobalt and iron. 相似文献
56.
《Particuology》2023
Ni-rich layered cathodes have become the promising candidates for the next-generation high-energy Li-ion batteries due to their high energy density and competitive cost. However, they suffer from rapid capacity fading due to the structural and interfacial instability upon long-term operation. Herein, the Ti-doped and LiYO2-coated Ni-rich layered cathode has been synthesized via a facile one-step sintering strategy, which significantly restrains the interfacial parasitic side reactions and enhances the structural stability. Specifically, the trace Ti4+ doping greatly stabilizes the lattice oxygen and alleviates the Li/Ni disorder while the LiYO2 coating layer can prevent the erosion of the cathode by the electrolyte during cycles. As a result, the Ti-NCM83@LYO delivers a high specific capacity of 135 mAh g−1 even at 10C and there is almost no capacity loss at 1C for 100 cycles. This work provides a simple one-step dual-modification strategy to meet the commercial requirements of Ni-rich cathodes. 相似文献
57.
《等离子体物理论文集》2017,57(2):58-66
Plasma jets from conventional non‐transferred arc plasma devices are usually operated in turbulent flows at atmospheric pressure. In this paper, a novel non‐transferred arc plasma device with multiple cathodes is introduced to produce long, laminar plasma jets at atmospheric pressure. A pure helium atmosphere is used to produce a laminar plasma jet with a maximum length of >60 cm. The influence of gas components, arc currents, anode nozzle diameter, and gas flow rate on the jet characteristics is experimentally studied. The results reveal that the length of the plasma jet increases with increasing helium content and arc current but decreases with increasing nozzle diameter. As the gas flow rate increases, the length of the plasma jet initially increases and then decreases. Accordingly, the plasma jet is transformed from a laminar state to a transitional state and finally to a turbulent state. Furthermore, the anode arc root behaviours corresponding to different plasma jet flows are studied. In conclusion, the multiple stationary arc roots that exist on the anode just inside the nozzle entrance are favourable for the generation of a laminar plasma jet in this device. 相似文献
58.
The introduction of the Li‐ion battery has revolutionized the electronics industry due to its high energy density. Magnesium batteries may have the potential to exceed the energy densities of Li‐ion batteries. Herein, the major advancements in magnesium electrochemistry and the challenges that must be overcome to realize a practical magnesium battery are discussed. So too are the controversial realities of current magnesium battery research and their implications. 相似文献
59.
Atomic Insights into the Enhanced Surface Stability in High Voltage Cathode Materials by Ultrathin Coating
下载免费PDF全文
![点击此处可从《Advanced functional materials》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Xin Fang Feng Lin Dennis Nordlund Matthew Mecklenburg Mingyuan Ge Jiepeng Rong Anyi Zhang Chenfei Shen Yihang Liu Yu Cao Marca M. Doeff Chongwu Zhou 《Advanced functional materials》2017,27(7)
Surface properties of electrode materials play a critical role in the function of batteries. Therefore, surface modifications, such as coatings, have been widely used to improve battery performance. Understanding how these coatings function to improve battery performance is crucial for both scientific research and applications. In this study the electrochemical performance of coated and uncoated LiNi0.5Mn1.5O4 (LNMO) electrodes is correlated with ensemble‐averaged soft X‐ray absorption spectroscopy (XAS) and spatially resolved scanning transmission electron microscopy‐electron energy loss spectroscopy (STEM‐EELS) to illustrate the mechanism of how ultrathin layer Al2O3 coatings improve the cycle life of LiNi0.5Mn1.5O4. Mn2+ evolution on the surface is clearly observed in the uncoated sample, which results from the reaction between the electrolytic solution and the surfaces of LiNi0.5Mn1.5O4 particles, and also possibly atomic structure reconstructions and oxygen loss from the surface region in LiNi0.5Mn1.5O4. The coating effectively suppresses Mn2+ evolution and improves the battery performance by decelerating the impedance buildup from the surface passivation. This study demonstrates the importance of combining ensemble‐averaged techniques (e.g., XAS) with localized techniques (e.g., STEM‐EELS), as the latter may yield unrepresentative information due to the limited number of studied particles, and sheds light on the design of future coating processes and materials. 相似文献
60.
New Strategy for Polysulfide Protection Based on Atomic Layer Deposition of TiO2 onto Ferroelectric‐Encapsulated Cathode: Toward Ultrastable Free‐Standing Room Temperature Sodium–Sulfur Batteries
下载免费PDF全文
![点击此处可从《Advanced functional materials》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dingtao Ma Yongliang Li Jingbo Yang Hongwei Mi Shan Luo Libo Deng Chaoyi Yan Muhammad Rauf Peixin Zhang Xueliang Sun Xiangzhong Ren Jianqing Li Han Zhang 《Advanced functional materials》2018,28(11)
The room temperature (RT) sodium–sulfur batteries (Na–S) hold great promise for practical applications including energy storage and conversion due to high energy density, long lifespan, and low cost, as well based on the abundant reserves of both sodium metal and sulfur. Herein, freestanding (C/S/BaTiO3)@TiO2 (CSB@TiO2) electrode with only ≈3 wt% of BaTiO3 additive and ≈4 nm thickness of amorphous TiO2 atomic layer deposition protective layer is rational designed, and first used for RT Na–S batteries. Results show that such cathode material exhibits high rate capability and excellent durability compared with pure C/S and C/S/BaTiO3 electrodes. Notably, this CSB@TiO2 electrode performs a discharge capacity of 524.8 and 382 mA h g?1 after 1400 cycles at 1 A g?1 and 3000 cycles at 2 A g?1, respectively. Such superior electrochemical performance is mainly attributed from the “BaTiO3‐C‐TiO2” synergetic structure within the matrix, which enables effectively inhibiting the shuttle effect, restraining the volumetric variation and stabilizing the ionic transport interface. 相似文献