首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   502篇
  国内免费   8篇
  完全免费   469篇
  物理学   979篇
  2020年   4篇
  2019年   34篇
  2018年   96篇
  2017年   103篇
  2016年   76篇
  2015年   72篇
  2014年   144篇
  2013年   96篇
  2012年   122篇
  2011年   138篇
  2010年   45篇
  2009年   34篇
  2008年   11篇
  2007年   3篇
  2006年   1篇
排序方式: 共有979条查询结果,搜索用时 31 毫秒
1.
基于石墨烯可饱和吸收被动锁模超快全固体激光器的研究   总被引:5,自引:0,他引:5  
石墨烯具有饱和恢复时间极短、导热性好、吸收带宽、损耗低、成本低廉且容易制备等优点,被认为是光电子应用中理想的半导体可饱和吸收体材料,近几年受到广泛的关注。介绍了本课题组最近在石墨烯锁模超快全固体激光器研究中取得的一些进展。在用液相剥离方法成功制备出尺寸大于20μm的石墨烯薄片的基础上,将其应用于全固态Nd∶GdVO4激光器,实现了脉宽16 ps、平均功率360 mW的锁模激光输出,单脉冲能量为8.4 nJ;继而在宽带增益介质Yb∶KGW晶体中又实现了脉宽为489 fs的超快激光,平均功率564 mW。  相似文献
2.
An ultrasound-assisted method was used for synthesizing nanosized Pt-graphene oxide (GO)-TiO2 photocatalyst. The Pt-GO-TiO2 nanoparticles were characterized by diffused reflectance spectroscopy, X-ray diffraction, N2 BET adsorption-desorption measurements, atomic force microscopy and transmission electron microscopy. The photocatalytic and sonophotocatalytic degradation of a commonly used anionic surfactant, dodecylbenzenesulfonate (DBS), in aqueous solution was carried out using Pt-GO-TiO2 nanoparticles in order to evaluate the photocatalytic efficiency. For comparison purpose, sonolytic degradation of DBS was carried out. The Pt-GO-TiO2 catalyst degraded DBS at a higher rate than P-25 (TiO2), prepared TiO2 or GO-TiO2 photocatalysts. The mineralization of DBS was enhanced by a factor of 3 using Pt-GO-TiO2 compared to the P-25 (TiO2). In the presence of GO, an enhanced rate of DBS oxidation was observed and, when doped with platinum, mineralization of DBS was further enhanced. The Pt-GO-TiO2 catalyst also showed a considerable amount of degradation of DBS under visible light irradiation. The initial solution pH had an effect on the rate of photocatalytic oxidation of DBS, whereas no such effect of initial pH was observed in the sonochemical or sonophotocatalytic oxidation of DBS. The intermediate products formed during the degradation of DBS were monitored using electrospray mass spectrometry. The ability of GO to serve as a solid support to anchor platinum particles on GO-TiO2 is useful in developing new photocatalysts.  相似文献
3.
石墨烯纳米带电子结构的紧束缚法研究   总被引:2,自引:0,他引:2       下载免费PDF全文
胡海鑫  张振华  刘新海  邱明  丁开和 《物理学报》2009,58(10):7156-7161
在推导出的一般复式格子的π电子紧束缚能量色散关系的基础上,通过假定石墨烯纳米带的电子横向限制势为无穷大硬壁势,导出石墨烯纳米带的能量色散关系及石墨烯纳米带或为金属或为半导体的条件.结果表明:石墨烯纳米带的电子结构与其几何构型(对称性及宽度)密切相关,所以通过控制几何构型,可将其调制成金属或不同带隙的半导体.这意味着石墨烯纳米带对于发展新型纳米器件具有重要意义.  相似文献
4.
秦盟盟  纪伟  冯奕钰  封伟 《中国物理 B》2014,23(2):28103-028103
Transparent conductive graphene films are fabricated by the transfer printing of graphene aqueous dispersion followed by hydrohalic acids and thermal reduction. Results indicate that the graphene film reduced by hydroiodic acid (HI) reduction combined with thermal treatment shows a higher electrical conductivity than that reduced only by thermal treatment at the same transparency. A film with a sheet resistance of - 2400 D./sq at a transparency over 72% is obtained at a typical wavelength of 550 nm.  相似文献
5.
氧化石墨烯被动调Q掺铒光纤激光器   总被引:2,自引:1,他引:1  
报道了基于氧化石墨烯的被动调Q掺铒光纤激光器。激光器采用环形腔结构,调Q器件为自制的氧化石墨烯可饱和吸收镜。泵浦功率在81~505 mW范围内时,得到了重复频率68~124 kHz的稳定的调Q脉冲输出,脉宽为0.47~1.60 μs。由于泵浦功率限制,激光器最大输出功率为10 mW, 相应单脉冲能量为80.6 nJ。此种基于氧化石墨烯可饱和吸收体的被动调Q光纤激光器体积小、成本低廉、结构简单、稳定性高、光束质量高,具有广阔的应用前景。  相似文献
6.
石墨烯/银纳米复合材料的制备及其影响因素研究   总被引:2,自引:0,他引:2       下载免费PDF全文
范冰冰  郭焕焕  李稳  贾瑜  张锐 《物理学报》2013,62(14):148101-148101
以硝酸银、鳞片石墨为原料, 在强碱环境下, 制备得到石墨烯/银纳米复合材料, 采用X射线衍射、红外吸收光谱、透射电子显微镜、紫外可见分光光度计对所制备的石墨 烯/银纳米复合材料进行了表征.结果表明: 氧化石墨烯和银离子在强碱NaOH的作用下, 氧化石墨烯失去部分含氧官能团, 被部分还原为石墨烯(rGO), 银离子被还原为纳米银颗粒, 均匀分布在氧化石墨烯片层表面, 颗粒大小和分布受硝酸银用量、反应温度、NaOH的加入顺序及前驱物混合方式等因素影响, 在GO与Ag粒子质量比为 1:1.08时, 负载在石墨烯片层上的银纳米颗粒集中在12 nm左右. 关键词: 石墨烯/银纳米复合材料 强碱溶液  相似文献
7.
In this work, an one-step approach to synthesize a CdS nanorod/graphene nanosheet (CdS/GNS) nanocomposite by the pyrolysis of a single-source precursor (bis(2-mercaptobenzothiazolato)-cadmium (II)) under nitrogen atmosphere were reported. X-ray diffraction result showed that the CdS nanorods belong to hexagonal crystal system. Transmission electron microscopy observations demonstrated that the CdS nanorods were coated by the graphene nanosheets effectively. Furthermore, the optical properties of the CdS/GNS nanocomposite were characterized by fluorescence spectroscopy. The nanocomposite displayed remarkable fluorescence quenching effect, implying that there was a high-efficiency energy transfer between graphene nanosheets and coated CdS nanorods, which could be applied in new optoelectronic or photovoltaic devices.  相似文献
8.
Graphene based silicone thermal greases   总被引:1,自引:0,他引:1  
Two kinds of silicone grease containing graphene nanoplatelets or reduced graphene oxide were prepared, and their thermophysical properties have been investigated. When the volume fraction was 1%, the reduced graphene oxide was the most effective additive to enhance the heat transfer properties of silicone, and graphene nanoplatelet was slightly inferior to the former. While when the concentration was enhanced, the viscosity of silicone grease containing reduced graphene oxide became very large due to its rich pore structure. Graphene nanoplatelet was efficient for the thermal conductivity enhancement of silicone grease, and it provided a thermal conductivity enhancement was up to 668%668% (loading of 4.25 vol.%4.25 vol.%). The experimental result is in excellent agreement with the recently developed theoretical model analyzing the thermal conductivity of isotropic composites containing randomly embedded GNPs, and it validates that graphene is an effective thermally conducting filler to let grease have high thermal conductivity with low filler content.  相似文献
9.
室温下石墨烯的霍尔效应实验研究   总被引:1,自引:0,他引:1  
对用化学气相沉积法(CVD)研制的长、宽均为1.23 cm,厚度为3个原子层尺寸的石墨烯样品,进行了室温下的霍尔效应相关研究。实验中电极与石墨烯之间有良好的欧姆接触。通过范德堡法测量了样品在磁场强度为0.353 T,不同电流强度下的霍尔电压,并对结果进行处理分析,得到石墨烯的霍尔系数RH=7.00×10-7m3/C、载流子浓度n=10.52×1024/m3、霍尔元件乘积灵敏度KH=6.87×102m2/C。  相似文献
10.
氮掺杂石墨烯纳米结构的等离激元激发(英文)   总被引:1,自引:0,他引:1  
尹海峰  陈广萍  向功周  张红 《发光学报》2014,(11):1297-1305
基于含时密度泛函理论,研究了氮掺杂石墨烯纳米结构的等离激元特性。吡啶型氮掺杂不影响石墨烯纳米结构的等离激元激发特性,而取代型氮掺杂主要基于石墨烯纳米结构对称性的改变和体系中电子密度的增加来影响石墨烯纳米结构的等离激元共振。相对于纯六角石墨烯纳米结构,在低能共振区,取代型氮掺杂六角石墨烯纳米结构的等离激元共振能量发生了红移。相对于纯矩形石墨烯纳米结构,在低能共振区,取代型氮掺杂矩形石墨烯纳米结构沿扶手椅型边界方向激发时,其等离激元共振能量发生了蓝移;沿Z字型边界激发时,其主要的等离激元共振模式受掺杂氮的影响较小。  相似文献
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号