排序方式: 共有31条查询结果,搜索用时 15 毫秒
21.
22.
23.
Bai M Roser T Ahrens L Alekseev IG Alessi J Beebe-Wang J Blaskiewicz M Bravar A Brennan JM Bruno D Bunce G Courant E Drees A Fischer W Gardner C Gill R Glenn J Haeberli W Huang H Jinnouchi O Kewisch J Luccio A Luo Y Nakagawa I Okada H Pilat F Mackay WW Makdisi Y Montag C Ptitsyn V Satogata T Stephenson E Svirida D Tepikian S Trbojevic D Tsoupas N Wise T Zelenski A Zeno K Zhang SY 《Physical review letters》2006,96(17):174801
The Brookhaven Relativistic Heavy Ion Collider (RHIC) has been providing collisions of polarized protons at a beam energy of 100 GeV since 2001. Equipped with two full Siberian snakes in each ring, polarization is preserved during acceleration from injection to 100 GeV. However, the intrinsic spin resonances beyond 100 GeV are about a factor of 2 stronger than those below 100 GeV making it important to examine the impact of these strong intrinsic spin resonances on polarization survival and the tolerance for vertical orbit distortions. Polarized protons were first accelerated to the record energy of 205 GeV in RHIC with a significant polarization measured at top energy in 2005. This Letter presents the results and discusses the sensitivity of the polarization survival to orbit distortions. 相似文献
24.
Interactions between poly(ethylene oxide) and fatty acids sodium salts studied by surface tension measurements 总被引:1,自引:0,他引:1
This work focuses onto the interactions between poly(ethylene oxide) (PEO) and fatty acids, in order to set their potential role of contaminants for PEO-based retention systems. Surface tension measurements were used to investigate PEO-fatty acid systems and they made it possible to clearly point out the interactions between the polymer and the sodium octadecylcarboxylates with different degrees of unsaturation. The observed interaction seems to be dependent on the fatty acids' solubility, the increase of which leads to less pronounced phenomena, which are, in contrast, emphasized by the increase in PEO chain length. 相似文献
25.
We report the results of a semiempirical PM3 study of the 1,4 cycloaddition reaction of substituted λ3-phosphabenzenes with alkynes. The influence of the nature, position and steric hindrance of substituents on the reaction
energy is studied. Except for some values, the results are in reasonable agreement with experimental observations and electronic
effects of substituents. 相似文献
26.
We report on a polarization-sensitive optical gain in a blue-emitting Si/SiO(2) nanocrystalline system having a high degree of emission polarization memory. This system can show a positive optical gain or optical loss depending on the polarization state of the pump and emitted light. Under optical gain conditions, the degree of polarization of the amplified spontaneous emission increases with the pumping fluence. This effect has been attributed to an increase in the stimulated emission efficiency occurring for the linearly polarized emission component characterized by high photon occupation numbers (stimulating photon flux). This finding is independently supported by other experimental observations. The occurrence of polarization dependent stimulated emission strongly indicates the relevance of morphological effects in light emission from ultrasmall elongated silicon nanostructures. 相似文献
27.
28.
Guttenberg Z Muller H Habermüller H Geisbauer A Pipper J Felbel J Kielpinski M Scriba J Wixforth A 《Lab on a chip》2005,5(3):308-317
We have developed a microfluidic device operating at a planar surface instead of a closed channel network. The fluid is transported in single droplets using surface acoustic waves (SAW) on a piezoelectric LiNbO(3) substrate. The surface of the piezo is chemically structured to induce high contact angles of the droplets or enclose areas where the liquid can wet the substrate. Combining the SAW technique with thin film resistance heaters, a biological analysis chip with integrated DNA amplification by PCR and hybridization was designed. To prevent evaporation of the PCR reagents at high temperatures the sample is enclosed in droplets of mineral oil. On this chip the SAW resolves dried primers, shifts the oil capped liquid between the two heaters and mixes during hybridization. The chip is able to perform a highly sensitive, fast and specific PCR with a volume as low as 200 nl. During the temperature cycles an online monitoring of the DNA concentration is feasible with an optical unit, providing a sensitivity of 0.1 ng. After PCR the product is moved to the second heater for the hybridization on a spotted DNA array. With our chip we were able to detect a single nucleotide polymorphism (SNP) responsible for the Leiden Factor V syndrome from human blood. 相似文献
29.
Dissociation Energy Computations for Saline Bonds Implied in Interactions Mediated by Peptidoglicans
Simona Muntean Ludovic Kurunczi Cristian Bologa Gheorghe Ilia Zeno Simon 《Macromolecular Symposia》2006,235(1):215-219
Summary: Dissociation energy and hydration energy calculations, in water solution, are presented for saline bonds mediated by Ca2+ and Mg2+ ions with Brőnstedt type bases ( COO , OSO3 , OH). A computationally intensive method, Polarisable Continuum Model (PCM) using 6-31G* basis set, was applied. Hydration energies were computed by various methods, as well as dissociation energies of some L2M complexes. L2Ca complexes result as more stable against dissociation than L2Mg complexes. Hydration energy calculation results, for some of the methods, here used, seem rather reliable as compared to experimental results. 相似文献
30.