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991.
992.
We consider the influence of the local squeezed vacuum fields on two initially entangled two-qubit system. By considering the upper bound of entanglement under time evolution, we find that the decay of the quantum entanglement shows different behavior for different time scales (t?max{(2βA)−1,(2βB)−1} and t?min{(2βA)−1,(2βB)−1}). The relative phase of the squeezing environment can also affect the entanglement dynamics profoundly. 相似文献
993.
Exact solutions for KdV system equations hierarchy are obtained by using the inverse scattering transform. Exact solutions of isospectral KdV hierarchy, nonisospectral KdV hierarchies and τ-equations related to the KdV spectral problem are obtained by reduction. The interaction of two solitons is investigated. 相似文献
994.
Babsky AM Zhang H Hekmatyar SK Hutchins GD Bansal N 《Magnetic resonance imaging》2007,25(7):1015-1023
The effects of 5-fluorouracil (5FU, 150 mg/kg, ip) on subcutaneously implanted radiation-induced fibrosarcoma (RIF-1) tumors were monitored by in vivo (1)H MRI to evaluate the water apparent diffusion coefficient (ADC), by single-quantum (SQ) and triple-quantum-filtered (TQF) (23)Na MRI to evaluate compartmental Na(+) content and by positron emission tomography (PET) to evaluate 2-[(18)F]fluoro-2-deoxy-d-glucose (FDG) uptake in the tumor. The MRI experiments were performed on untreated control and treated mice once before and then daily for 3 days after treatment. The PET experiments were performed on separate groups of age- and tumor-volume-matched animals once before and then 3 days after treatment. Tumor volumes significantly decreased in treated animals 2 and 3 days posttreatment. At the same time points, in vivo MRI measurements showed an increase in both total tissue SQ (23)Na signal intensity (SI) and water ADC in treated tumors while control tumors showed no change in these parameters. TQF (23)Na SI and FDG uptake were significantly lower in treated tumors compared with control tumors 3 days after 5FU treatment. The correlated increases in total tissue (23)Na SI and water ADC following chemotherapy reflect an increase in extracellular space, while the lower TQF (23)Na SI and FDG uptake in treated tumors compared with control tumors suggest a shift in tumor metabolism from glycolysis to oxidation and/or a decrease in cell density. 相似文献
995.
Agkisacutacin isolated from the venom of Agkistrodon acutus is a coagulation factor IX / coagulation factor X-binding protein with marked anticoagulant- and platelet-modulating activities.
Ca2+ ion-induced stabilization and refolding of Agkisacutacin have been studied by following fluorescent measurements. Ca2+ ions not only increase the structural stability of agkisacutacin against GdnHCl denaturation, but also induce its refolding.
The GdnHCl-induced unfolding of the apo-agkisacutacin and the purified agkisacutacin is a single-step process with no detectable
intermediate state. Ca2+ ions play an important role in the stabilization of the structure of agkisacutacin. Ca2+-stabilized agkisacutacin exhibits higher resistance to GdnHCl denaturation than the apo-agkisacutacin. It is possible to
induce refolding of the unfolded apo-agkisacutacin merely by adding 1 mM Ca2+ ions without changing the concentration of the denaturant. The kinetic result of Ca2+-induced refolding provides evidences for that agkisacutacin consists of at least two refolding phases and the first phase
of Ca2+-induced refolding should involve the formation of the compact Ca2+-binding site regions, and subsequently, the protein undergoes further conformational rearrangements to form the native structure. 相似文献
996.
"研究了CdTe/CdO?nH2O核壳纳米复合物的水相合成及其光学特性. 以巯基乙酸为稳定剂通过氯化镉和碲氢化钠反应制备了碲化镉纳米晶. 在反应过程中, 反应前驱溶液中镉离子与碲离子的摩尔浓度比对最终制备的碲化镉纳米晶的荧光强度起到了极其重要的作用. 在pH值为8.2, 镉离子与碲离子摩尔浓度比为4.0的情况下,制备出了具有最强荧光强度的碲化镉量子点.之后,CdTe/CdO?nH2O核壳纳米复合物在水相中制备出来.在适当的氢氧化镉沉积在碲化镉纳米粒子表面后,碲化镉量子点的荧光大大增强.所制备的CdTe/C 相似文献
997.
聚苯胺/钡铁氧体复合材料的制备及电磁性能 总被引:1,自引:0,他引:1
"采用原位掺杂聚合法,将聚苯胺对粒径在60~80 nm的M型钡铁氧体颗粒(BaFe12O19)进行包覆,得到了具有导电性和磁性的复合材料.通过X射线衍射、傅利叶变换红外光谱仪、扫描电镜和透射电镜等测试手段对材料的形貌和结构进行了表征.结果表明:PANI链段与BaFe12O19颗粒之间存在着作用力.使用振动磁强计和四探针法测定了复合材料的磁性能与电性能,其中50%复合材料的饱和磁化强度为22.2 emu/g,电导率为0.069 S/cm." 相似文献
998.
In this short letter, we describe the effects of low temperature on the Metal-Enhanced Fluorescence (MEF) phenomenon. Fluorophores
close to Silver Island Films (SiFs) show on average two- to ten-fold enhancements in their fluorescence signatures at room
temperature. However, at 77 K, we have observed that MEF is even more pronounced as compared to an identical glass control
sample. We also demonstrate that the further enhancements in MEF occur at low temperature over a range of visible wavelengths
for different fluorophores, for both SiFs and 20 nm surface deposited gold colloids. 相似文献
999.
Li Chao Yin Siyu Zhou Hongbo Zhang Yajiao Li Yongxiu Chen Yufeng 《Journal of Sol-Gel Science and Technology》2021,99(2):430-443
Journal of Sol-Gel Science and Technology - A drug delivery system with near-infrared emissions response to drug delivery and release is essential as marking or targeting drug delivery system. For... 相似文献
1000.
Rui Hong Yi-Xin Jiang Jie Leng Ming-Jin Liu Kai-Zhi Shen Qiang Fu Jie Zhang 《高分子科学》2021,39(6):756-769
General-purpose plastics with high strength and toughness have been in great demand for structural engineering applications. To achieve the reinforcement and broaden the application scope of high-density polyethylene(HDPE), multi-flow vibration injection molding(MFVIM) and ultrahigh molecular weight polyethylene(UHMWPE) are synergistically employed in this work. Herein, the MFVIM has better shear layer control ability and higher fabrication advantage for complex parts than other analogous novel injection molding technologies reported.The reinforcing effect of various filling times and UHMWPE contents as well as the corresponding microstructure evolution are investigated.When 5 wt% UHMWPE is added, MFVIM process with six flow times thickens the shear layer to the whole thickness. The tensile strength and modulus increase to 2.14 and 1.39 times, respectively, compared to neat HDPE on the premise of remaining 70% impact strength. Structural characterizations indicate that the enhancement is attributed to the improvement of shish-kebab content and lamellae compactness, as well as related to the corresponding size distributions of undissolved UHMWPE particles. This novel injection molding technology with great industrial prospects provides a facile and effective strategy to broaden the engineering applications of HDPE materials. Besides, excessive UHMWPE may impair the synergistic enhancement effect, which is also reasonably explained. 相似文献