排序方式: 共有21条查询结果,搜索用时 15 毫秒
11.
Mantica P Gorini G Hogeweij GM Lopes Cardozo NJ Schilham AM 《Physical review letters》2000,85(21):4534-4537
Layers of reduced electron heat transport ("transport barriers") have been observed in the Rijnhuizen Tokamak Project when the plasma is dominantly heated by electron cyclotron heating (ECH). Experiments into the properties of the transport barriers are reported. Modulation of the ECH power was used to probe electron heat transport in the barriers by means of propagating electron temperature perturbations. The observed propagation shows that transport inside the barriers is dominated by heat convection. This convection is inward, i.e., up the temperature gradient. 相似文献
12.
A new route to sterically tuned, chelating bis(aryloxide) ligands is described and demonstrated by the synthesis of 2,2'-ethylenebis(6-isopropylphenol) (1, H(2)BIPP) and transition metal complexes of its dianion. The utility of these ligands in titanium and tantalum organometallic chemistry is shown in the alkylation of (BIPP)TiCl(2) (7) to form (BIPP)TiMe(2) (8) and (BIPP)Ti(CH(2)Ph)(2) (9) and in the alkylation of (BIPP)TaCl(3) (10) and its base adducts to form (BIPP)TaMe(3) (14) and (BIPP)Ta(CH(2)Ph)(3) (13). Structural comparisons of the chelating 2,2'-ethylenebis(6-isopropylphenoxide) (BIPP) ligand with its analogous, nonchelating bis(2,6-dialkylaryloxide) ligand set are examined in the X-ray diffraction studies of (BIPP)TaCl(3)(THF).THF (11.THF) and (BIPP)Ta(CH(2)C(6)H(5))(3) (13). 相似文献
13.
14.
15.
NJ Oldham 《Rapid communications in mass spectrometry : RCM》1999,13(16):1694-1698
Ion/molecule reactions leading to formation of the diagnostically useful [C(3)H(4)N](+) ion (m/z 54), from acetonitrile CI plasma, have been studied using a tandem quadrupole mass spectrometer. Evidence is presented to demonstrate that [C(3)H(4)N](+) is produced from an ion/molecule reaction between [C(2)H(2)N](+) (m/z 40) and neutral acetonitrile, via a [C(4)H(5)N(2)](+) (m/z 81) intermediate. Loss of HCN, where the H atom arises from neutral acetonitrile and the CN group from [C(2)H(2)N](+) (m/z 40), leads to the production of [C(3)H(4)N](+) (m/z 54). These results are consistent with a proposed concerted elimination of HCN, generating m/z 54 as a methylene vinylidene ammonium ion. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
16.
17.
C. R. Davidson D. G. Foursa A. Lucero O. Sinkin W. Patterson A. Pilipetskii G. Mohs Neal S. Bergano 《中国光学快报(英文版)》2010,(9):831-836
We provide a review of our recent 100-Gb/s, high spectral efficiency (SE) experiment targeting transoceanic and regional undersea transmission distances. We demonstrated that simple pre-filtering at the transmitter together with a maximum a posteriori probability (MAP) detection algorithm can significantly improve SE. We transmitted 96×100-Gb/s pre-filtered polarization division multiplexed return-to-zero quadrature phase shift keyed (PDM-RZ-QPSK) channels with 300% SE over 10608 km using 52-km spans of 150-μm 2 fiber and simple single-stage erbium-doped fiber amplifiers (EDFAs). We also achieved 400% SE over 4368 km using similar techniques. 相似文献
18.
We have performed a series of neutron diffraction experiments from the magnetic order and the vortex lattice in single crystal
ErNi2B2C. The incommensurate magnetic structure develops additional even harmonics below the ‘ferromagnetic’ ordering temperature,
T
F of 2.3 K. This feature and the existence of rods of diffuse scattering suggest the development of ferromagnetic microdomain
walls. The magnetic structure is very sensitive to the application of a magnetic field with changes in modulation vector and
harmonic content. Studies of the vortex lattice show the presence of a 45° reorientation transition and a distorted hexagonal
to square transition as a function of applied field. Further distortions of the vortex lattice occur at T
N, but no changes are seen at T
F. 相似文献
19.
20.