排序方式: 共有47条查询结果,搜索用时 46 毫秒
1.
W. Gulden 《Fresenius' Journal of Analytical Chemistry》1967,226(4):367-368
Ohne Zusammenfassung 相似文献
2.
Clusters of galaxies are excellent probes of cosmic structure and evolution. X-ray studies of clusters provide some of their
key parameters, viz., temperature of the hot intra-cluster gas, its metallicity, X-ray luminosity and surface brightness giving
mass distribution and mass-flow rate in the case of cooling flows. X-ray measurements for a large sample of clusters have
lead to estimates of the total gravitating mass in them, which can be compared to the virial masses derived from dynamical
considerations and gravitational lensing in some of them. X-ray derived total masses are consistent with masses obtained from
the other methods after the effects due to the presence of cooling flows are taken into account in the analyses. Estimated
virial masses, lack of evolution in X-ray properties, and detection of several very hot clusters at high redshifts indicate
a Universe with a low value (≤ 0.3) for the Ω parameter. 相似文献
3.
4.
K. Dehnicke W. Gulden G. Dreyer A. W. Holldorf G. Siegemund 《Colloid and polymer science》1979,257(9):1009-1011
Ohne Zusammenfassung 相似文献
5.
Top-emitting Alas/AlGaAs vertical cavity surface emitting lasers emitting at 765 nm with minimum threshold currents of 0.6 mA and threshold voltages of 1.9 V have been grown by MOVPE. In order to keep the growth time low, we investigated the possibility to grow these structures at growth rates of 5 μm/h. Special attention was paid to the homogeneity that can be achieved over a 2″ wafer under these growth conditions. Spatially resolved reflectivity measurements on GaAs/AlAs distributed Bragg reflectors showed, that the growth rate varies less than 0.3% in the center of the wafer and decreases by 1% at the wafer edge. 相似文献
6.
J Ramón-Azcón S Ahadian R Obregón G Camci-Unal S Ostrovidov V Hosseini H Kaji K Ino H Shiku A Khademhosseini T Matsue 《Lab on a chip》2012,12(16):2959-2969
Establishing the 3D microscale organization of cells has numerous practical applications, such as in determining cell fate (e.g., proliferation, migration, differentiation, and apoptosis) and in making functional tissue constructs. One approach to spatially pattern cells is by dielectrophoresis (DEP). DEP has characteristics that are important for cell manipulation, such as high accuracy, speed, scalability, and the ability to handle both adherent and non-adherent cells. However, widespread application of this method is largely restricted because there is a limited number of suitable hydrogels for cell encapsulation. To date, polyethylene glycol-diacrylate (PEG-DA) and agarose have been used extensively for dielectric patterning of cells. In this study, we propose gelatin methacrylate (GelMA) as a promising hydrogel for use in cell dielectropatterning because of its biocompatibility and low viscosity. Compared to PEG hydrogels, GelMA hydrogels showed superior performance when making cell patterns for myoblast (C2C12) and endothelial (HUVEC) cells as well as in maintaining cell viability and growth. We also developed a simple and robust protocol for co-culture of these cells. Combined application of the GelMA hydrogels and the DEP technique is suitable for creating highly complex microscale tissues with important applications in fundamental cell biology and regenerative medicine in a rapid, accurate, and scalable manner. 相似文献
7.
8.
G. Auffermann G. Auffermann A. Simon Th. Gulden G. J. Kearley G. J. Kearley A. Ivanov 《无机化学与普通化学杂志》2001,627(3):307-311
We report on the incorporation of hydrogen into La2C3 and on the characterisation of its position. Temperature‐dependent X‐ray investigations show that the hydrogenation process is reversible and the product La2C3H1.5 is amorphous. In principle, IR and Raman spectroscopies can provide some structural information, but in the present study, they are of only limited value. Inelastic neutron scattering (INS) has advantages for measuring the H‐vibrations in La2C3H1.5 and these are compared with the results of molecular dynamics simulations. A structural model based on published pair‐potentials predicts that hydrogen (or deuterium) occupies the “tetrahedral” holes in the lanthanum sublattice. This model also accounts for the observed vibrational spectra. 相似文献
9.
10.