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201.
为了分析干法刻蚀对应变多量子阱(SMQWs)发光特性的影响,采用感应耦合等离子体(ICP)刻蚀技术对金属有机物化学气相沉积(MOCVD)生长的InGaN/AIGaN应变多量子阱覆盖层表面刻蚀了约95 nm。通过光致发光(PL)特性表征发现,干法刻蚀后量子阱光致发光强度较未刻蚀量子阱光致发光强度提高了近3倍。干法刻蚀后,量子阱表面呈现高低起伏状形貌,粗糙度提高,出射光在起伏状粗糙形貌表面反复散射,从而逃逸概率增大,有助于光致发光强度增强。理论计算结果得出表面形貌变化引起的量子阱光致发光强度增强因子约为1.3倍。另外,由于所采用的感应耦合等离子体功率较小,刻蚀损伤深度几乎不会达到量子阱阱层,然而干法刻蚀过程中Ar离子隧穿到量子阱阱层内部可能形成新的发光中心,从而使量子阱的发光强度得到提高。 相似文献
202.
Qiang Li Huiying Lao Jia Lin Yuping Chen Xianfeng Chen 《Applied Physics A: Materials Science & Processing》2011,105(1):125-129
In this paper, a 3D two-temperature model is introduced to investigate femtosecond ablation on aluminum film. 3D temperature
evolutions for both electrons and lattice are obtained, which present us a vivid view of the energy transformation process
during femtosecond ablation. Simulated 3D ablation craters irradiated by a single pulse with different energy are acquired,
from which we can easily and precisely predict crater depth and radius before ablation takes place. In the experiment we measure
the radii of the craters ablated by pulses with different energy and numbers delivered from a chirped pulse amplification
Ti: sapphire system. The threshold fluence for both single and multi pulses are obtained. Comparisons are made between results
of the experiment and relative simulated calculations show the reliability of our proposed calculation model. 相似文献
203.
204.
Dr. William Ndugire Dang Truong N. G. Hasitha Raviranga Jingzhe Lao Prof. Dr. Olof Ramström Prof. Dr. Mingdi Yan 《Angewandte Chemie (International ed. in English)》2023,62(11):e202214086
In this work, we show that the addition of thiourea (TU) initiated broad-spectrum antimicrobial activity of otherwise inactive D-maltose-capped gold nanoclusters (AuNC-Mal). For example, AuNC-Mal/TU was effective against multidrug-resistant Pseudomonas aeruginosa with a minimum inhibitory concentration (MIC) of 1 μg mL−1 (2.5 μM [Au]) while having 30–60 times lower in vitro cytotoxicity against mammalian cells. The reaction of AuNC-Mal and TU generated the antimicrobial species of [Au(TU)2]+ and smaller AuNCs. TU increased the accumulation of Au in bacteria and helped maintain the oxidation state as AuI (vs. AuIII). The modes of action included the inhibition of thioredoxin reductase, interference with the CuI regulation and depletion of ATP. Moreover, the antimicrobial activity did not change in the presence of colistin or carbonyl cyanide 3-chlorophenylhydrazone, suggesting that AuNC-Mal/TU was indifferent to the outer membrane barrier and to bacterial efflux pumps. 相似文献
205.
Bonhomme C Gervais C Folliet N Pourpoint F Diogo CC Lao J Jallot E Lacroix J Nedelec JM Iuga D Hanna JV Smith ME Xiang Y Du J Laurencin D 《Journal of the American Chemical Society》2012,134(30):12611-12628
Strontium is an element of fundamental importance in biomedical science. Indeed, it has been demonstrated that Sr(2+) ions can promote bone growth and inhibit bone resorption. Thus, the oral administration of Sr-containing medications has been used clinically to prevent osteoporosis, and Sr-containing biomaterials have been developed for implant and tissue engineering applications. The bioavailability of strontium metal cations in the body and their kinetics of release from materials will depend on their local environment. It is thus crucial to be able to characterize, in detail, strontium environments in disordered phases such as bioactive glasses, to understand their structure and rationalize their properties. In this paper, we demonstrate that (87)Sr NMR spectroscopy can serve as a valuable tool of investigation. First, the implementation of high-sensitivity (87)Sr solid-state NMR experiments is presented using (87)Sr-labeled strontium malonate (with DFS (double field sweep), QCPMG (quadrupolar Carr-Purcell-Meiboom-Gill), and WURST (wideband, uniform rate, and smooth truncation) excitation). Then, it is shown that GIPAW DFT (gauge including projector augmented wave density functional theory) calculations can accurately compute (87)Sr NMR parameters. Last and most importantly, (87)Sr NMR is used for the study of a (Ca,Sr)-silicate bioactive glass of limited Sr content (only ~9 wt %). The spectrum is interpreted using structural models of the glass, which are generated through molecular dynamics (MD) simulations and relaxed by DFT, before performing GIPAW calculations of (87)Sr NMR parameters. Finally, changes in the (87)Sr NMR spectrum after immersion of the glass in simulated body fluid (SBF) are reported and discussed. 相似文献
206.
Lao W Xu C Ji S You J Ou Q 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2000,56(11):2049-2060
The FTIR and FTR spectra of halogen (Cl, Br, I) substituted carbazole and their N-acetic and propionic acids have been recorded. A number of lines have been assigned on the basis of previous studies on the parent compound and by comparisons with the characteristic vibrations of their constituent structural units as well as comparing the spectra from FTIR and FTR. Some substituent-sensitive bands and characteristic bands were found. The electronic absorption spectra of these compounds in acetonitrile were also measured and are briefly discussed. 相似文献
207.
Yang Yu Jun Chen Songyang Jiang Chenjia Wang Ningya Liu Mengxiao Yang Panxiang Cheng Yao 《Journal of Solid State Electrochemistry》2023,27(5):1107-1118
Journal of Solid State Electrochemistry - A facile method was proposed to synthesize a Co3S4-based binder-free electrode (Co3S4/Ni foam) in an aqueous solution containing 1-thioglycerol, cobalt... 相似文献
208.
Dr. Shangfa Pan Prof. Peng Liu Qi Li Bin Zhu Prof. Xueli Liu Junchao Lao Prof. Jun Gao Prof. Lei Jiang 《Angewandte Chemie (International ed. in English)》2023,62(19):e202218129
Nanofluidic membranes have shown great promise in harvesting osmotic energy but its scalablity remains challenging since most studies only tested with a membrane area of ≈10−2 mm2 or smaller. We demonstrate that metal-organic-framework membranes with subnanometer pores can be used for scalable osmotic power generation from hypersaline water sources. Our membrane can be scaled up to a few mm2, and the power density can be stabilized at 1.7 W m−2. We reveal that the key is to improve the out-of-membrane conductance while keeping the membrane's charge selectivity, contradicting the previous conception that the ionic conductivity of the membrane plays the dominating role. We highlight that subnanometer pores are essential to ensure the charge selectivity in hypersaline water sources. Our results suggest the importance to engineer the interplay between the in-membrane and out-of-membrane ion transport properties for scalable osmotic power generation. 相似文献