全文获取类型
收费全文 | 100篇 |
免费 | 0篇 |
专业分类
化学 | 75篇 |
晶体学 | 1篇 |
力学 | 1篇 |
数学 | 2篇 |
物理学 | 21篇 |
出版年
2017年 | 1篇 |
2013年 | 2篇 |
2012年 | 3篇 |
2011年 | 3篇 |
2009年 | 1篇 |
2008年 | 3篇 |
2007年 | 3篇 |
2006年 | 5篇 |
2005年 | 14篇 |
2004年 | 7篇 |
2003年 | 2篇 |
2002年 | 7篇 |
2001年 | 7篇 |
1998年 | 1篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 5篇 |
1992年 | 6篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1980年 | 4篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1969年 | 2篇 |
1940年 | 1篇 |
1938年 | 1篇 |
1935年 | 1篇 |
排序方式: 共有100条查询结果,搜索用时 15 毫秒
31.
Bekyarova E Itkis ME Cabrera N Zhao B Yu A Gao J Haddon RC 《Journal of the American Chemical Society》2005,127(16):5990-5995
We present a study on the electronic behavior of films of as-prepared and purified single-walled carbon nanotubes (SWNTs) and demonstrate the important role that chemical functionalization plays in modifying their electronic properties, which in turn throws further light on the mechanism of action of SWNT-based sensors. Films of electric arc SWNTs were prepared by spraying, and optical spectroscopy was used to measure the effective film thickness. The room-temperature conductivities (sigma(RT)) of thin films deposited from as-prepared and purified SWNTs are in the range sigma(RT) = 250-400 S/cm, and the nonmetallic temperature dependence of the conductivity indicates the presence of tunneling barriers, which dominate the film conductivity. Chemical functionalization of SWNTs with octadecylamine (ODA) and poly(m-aminobenzenesulfonic acid) (PABS) significantly decreases the conductivity; sigma(RT) = 3 and 0.3 S/cm for SWNT-ODA and SWNT-PABS, respectively. 相似文献
32.
The first reported instance of an unsaturated -butyl ester as a lepidopteran sex pheromone is described including its identification and synthesis. 相似文献
33.
R.C. Haddon 《Tetrahedron》1972,28(14):3613-3633
The Biot-Savart shielding law is applied to a wide variety of annulenes in an effort to delineate the relationship between chemical shift and ring current. The success of the proton chemical shift/ring current analysis of the annulenes is interpreted to provide strong phenomenological evidence for the existence of diamagnetic and paramagnetic ring currents. 相似文献
34.
Brusso JL Clements OP Haddon RC Itkis ME Leitch AA Oakley RT Reed RW Richardson JF 《Journal of the American Chemical Society》2004,126(45):14692-14693
The molecular radical 1,3,2-dithiazolo[4,5-b]pyrazin-2-yl (PDTA) exhibits magnetic bistability just above room temperature, undergoing a well-defined hysteretic phase change with TC downward arrow = 297(1) K and TC upward arrow = 343(1) K. The crystal structures of the two phases of PDTA have been determined by single-crystal X-ray diffraction at 323(2) K. LT-PDTA consists of diamagnetic (S = 0) nearly superimposed pi-dimer stacks, while that of HT-PDTA comprises slipped stacks of pi-radicals (S = 1/2). The structural interconversion is suggested to proceed via the cooperative breaking and making of intermolecular S- - -N interactions and an inversion symmetry-preserving "domino cascade" of the pi-stacked rings. 相似文献
35.
Effect of van der Waals interactions on the Raman modes in single walled carbon nanotubes 总被引:4,自引:0,他引:4
Rao AM Chen J Richter E Schlecht U Eklund PC Haddon RC Venkateswaran UD Kwon YK Tománek D 《Physical review letters》2001,86(17):3895-3898
We have measured the Raman spectrum of individual single walled carbon nanotubes in solution and compare it to that obtained from the same starting material where the tubes are present in ordered bundles or ropes. Interestingly, the radial mode frequencies for the tubes in solution are found to be approximately 10 cm (-1) higher than those observed for tubes in a rope, in apparent contradiction to lattice dynamics predictions. We suggest that there is no such contradiction, and propose that the upshift is due rather to a decreased energy spacing of the Van Hove singularities in isolated tubes over the spacings in a rope, thereby allowing the same laser excitation to excite different diameter tubes in these two samples. 相似文献
36.
Ester-functionalized soluble single-walled carbon nanotubes 总被引:2,自引:0,他引:2
M.A. Hamon H. Hui P. Bhowmik H.M.E. Itkis R.C. Haddon 《Applied Physics A: Materials Science & Processing》2002,74(3):333-338
We report the preparation of soluble ester- functionalized single-wall carbon nanotubes (sSWNT-COO(CH2)17CH3). By use of solution phase IR spectroscopy we are able to compare the ratio of the carbon atoms in the SWNT backbone to the
carbon atoms in the ester and amide functionalities of s-SWNTs.
Received: 16 July 2001 / Accepted: 3 December 2001 / Published online: 4 March 2002 相似文献
37.
It is shown that there is a direct relationship between the resonance energies and the HOMO-LUMO energy gap in the [4n+2]annulenes - thereby demonstrating the connection between the thermodynamic and kinetic criteria of aromatic character. 相似文献
38.
39.
Hu H Yu A Kim E Zhao B Itkis ME Bekyarova E Haddon RC 《The journal of physical chemistry. B》2005,109(23):11520-11524
We report a systematic study of the purification of nitric acid treated single-walled carbon nanotubes (SWNTs) by centrifugation at constant pH. The progress of the purification procedure was followed by estimating the purity by solution-phase near-infrared spectroscopy, and it was found that the sediment obtained by centrifugation at pH 2 had the highest purity. The stability of the aqueous dispersions of SWNTs and carbonaceous impurities (CIMP) after nitric acid treatment was investigated by measuring their zeta potential and the concentration of acidic sites. We found that, at lower pH, the CIMP has a higher zeta potential than nitric acid treated SWNTs, and it is this factor that allowed the separation of the carbonaceous impurities via centrifugation and the concomitant purification of the SWNTs. 相似文献
40.
Synthesis and characterization of water soluble single-walled carbon nanotube graft copolymers 总被引:6,自引:0,他引:6
Poly(aminobenzene sulfonic acid) (PABS) and polyethylene glycol (PEG) were covalently attached to single-walled carbon nanotubes (SWNTs) to form water-soluble graft copolymers. Quantitative near-IR (NIR) spectroscopic studies of these SWNT graft copolymers indicate a water solubility of about 5 mg/mL, and atomic force microscopy studies show a fairly uniform length and diameter. On the basis of thermogravimetric analysis, the loading of SWNTs in the graft copolymers is estimated to be 30% for SWNT-PABS and 71% for SWNT-PEG. NIR spectroscopic studies of SWNT-PABS show that this graft copolymer has a ground state that is a hybrid of the electronic structures of the isolated PABS and SWNT macromolecules. 相似文献