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51.
The effective Hamiltonian and the renormalized mass of surface polaron, where the electron is strongly coupled with the surface optical (SO) phonons but weakly or intermediately coupled with the bulk longit udinal-optical (LO) phonons, were first reviewed. The self-energy and the renormalized mass of the polaron for the polar crystals of potassium iodide, silver chloride and silver bromide are evaluated as a function of the depth Gom the crystal surface. Results of our calculation indicate that the effect of the electron-SO phonon interaction is dominant only within a very small layer from the crystal surface. Its justification awaits further experimental results. 相似文献
52.
Enediynes are a novel class of naturally occurring antitumor antibiotics capable of causing DNA strand cleavage by hydrogen atom abstraction from the deoxyribose backbone. During the past decade, numerous synthetic methods have been developed to synthesize the naturally occurring and the "designed" enediynes for biomedical studies. Recently, we have succeeded in assembling the cis-enediynes 2 by a novel and high-yielding allylic rearrangement under mild reaction conditions (Eq 1).1-3 This methodology has been used to synthesize a 10-membered ring enediyne3 which exhibits DNA cleavage activity. 相似文献
53.
PreliminaryStudyonDestructionofFreon12byInductivelyCoupledPlasma——DevelopmentofICPTechnologyforWasteDestructionCHENDeng-yunan... 相似文献
54.
Sukkum Ngullie CHANG Jeong Jun LEE Hyun Jin KIM Sun Chul KANG 《Turkish Journal of Chemistry》2021,45(4):1155
Vitamin D2 (vit. D2) is a nutraceutical essentially needed for good health. However, it is susceptible to oxygen and high temperature. The use of natural products such as bioflavonoids possessing anti-degradative effect of vit. D2 degradation has not been described before. A combinational effect of vit. D2 with quercetin showed a positive effect and inhibited vit. D2 degradation when exposed to high temperature (50 ℃ and 75 ℃) at different time points. The results obtained revealed vit. D2 degradation was drastically increased with longer incubation under thermal treatment. However, quercetin and vit. D2 groups were able to significantly inhibit the degradation of vit. D2 and stabilize it, evaluated through the retention percentage. We also exposed vit. D2 at solutions with different pH values (1, 4, 5, 7, 10). Quercetin exerted vit. D2 anti-degradation at different pH values as well as under thermal pressure at different time points. Conclusively, quercetin can be an effective way to reduce temperature and pH induced degradation of vit. D2. 相似文献
55.
Applied Physics A 53, no. 3 (1991) 相似文献
56.
57.
We optimize the room-temperature etching of InP using Cl2/CH4/H2 and Cl2/N2 inductively coupled plasma reactive ions. A design of experiment is used in the optimization. The results, in terms of etch rate, surface roughness and etched profile, are presented. These Cl2-based recipes do not require substrate heating and thus can be more cost effectively and widely applied. The Cl2/CH4/H2 process is able to give a higher etch rate (about 850 nm/min) and cleaner surface with less polymer formation compared to the conventional CH4/H2 process. The Cl2/N2 process produces even higher etch rate (as high as 2μm/rain), but rougher surface with slight sidewall undercut. The Cl2/N2 process also has no polymer formation due to the absence of methane gas. Both the processes give very good selectivity to the silicon dioxide (SiO2) etch mask. The selectivity of InP to the oxide mask (up to 55:1) for the Cl2/N2 process is one of the highest reported so far. The etched structures possess reasonably good sidewall verticality and surface quality comparable to that obtained under elevated temperature condition (〉 200℃). 相似文献
58.
Applied Physics A 49, no. 2 (1989) 相似文献
59.
The time-averaged spontaneous radiation power and its spectrum are derived analytically. The collective mode is taken to be electron-cyclotron mode driven by the relativistic electron beam existing in the unstable and late phases of plasma focus. The infrared range radiation calculated is in agreement with experimental observation. 相似文献
60.
微波合成PtRu/C纳米催化剂及其对甲醇电化学氧化性能 总被引:4,自引:0,他引:4
PtRu/carbon nanosized catalyst with PtRu loading of 26.4wt% (Rt∶Ru=1.0∶1.0~1.1) was rapidly synthesized by the microwave polyol process employing the ethylene glycol solution of H2PtCl6 and RuCl3 as precursors in the presence of XC-72 carbon support. TEM observations demonstrated that microwave-prepared PtRu nanoparticles were narrowly distributed and highly dispersed on the carbon with an average size of 3.9 nm. Electrochemical experiments showed that microwave-synthesized PtRu/carbon catalyst exhibited very high catalytic activity for electro-oxidation of liquid methanol at room temperature. 相似文献