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11.
Yusong Tu Pei Li Jiajia Sun Jie Jiang Fangfang Dai Chengzhang Li Yuanyan Wu Liang Chen Guosheng Shi Yanwen Tan Haiping Fang 《Advanced functional materials》2021,31(13):2008018
Despite long-term efforts for exploring antibacterial agents or drugs, potentiating antibacterial activity and meanwhile minimizing toxicity to the environment remains a challenge. Here, it is experimentally shown that the functionality of reduced graphene oxide (rGO) through copper ions displays selective antibacterial activity that is significantly stronger than that of rGO itself and no toxicity to mammalian cells. Remarkably, this antibacterial activity is two-orders-of-magnitude greater than the activity of its surrounding copper ions. It is demonstrated that rGO is functionalized through the cation–π interaction to massively adsorb copper ions to form a rGO–copper composite and result in an extremely low concentration level of surrounding copper ions (less than ≈0.5 µm ). These copper ions on rGO are positively charged and strongly interact with negatively charged bacterial cells to selectively achieve antibacterial activity, while rGO exhibits the functionality to not only actuate rapid delivery of copper ions and massive assembly onto bacterial cells but also result in the valence shift in the copper ions from Cu2+ into Cu+, which greatly enhances the antibacterial activity. Notably, this rGO functionality through cation–π interaction with copper ions can similarly achieve algaecidal activity but does not exert cytotoxicity against neutrally charged mammalian cells. 相似文献
12.
Xiao-Ya Shangguan Bao-Lun Fang Chen-Xiao Xu Yuan Tan Yan-Gang Chen Zhi-Jun Xia Wei Chen 《Ceramics International》2021,47(5):6318-6328
A series of direct Z-scheme FeIn2S4/Bi2WO6 hierarchical heterostructures with intimate interface contacts were synthesized by in-situ growth route and characterized by systematical analyses. All as-prepared FeIn2S4/Bi2WO6 nanocomposites showed significantly enhanced photocatalytic activity towards photodegradation for the removal of tetracycline hydrochloride (TCH) in comparison with individual FeIn2S4 and Bi2WO6. Meanwhile, the highest photocatalytic degradation activity can be achieved by modulating adding amount of FeIn2S4 in FeIn2S4/Bi2WO6 nanocomposites and the optimized component ratio of FeIn2S4 to Bi2WO6 is determined to be 10 wt%. The enhanced photocatalytic activity could be ascribed to efficient separation between photogenerated holes and electrons based on the construction of direct Z-scheme system. The high photocatalytic stability of resultant 10 wt% FeIn2S4/Bi2WO6 nanocomposites was revealed through six successive recycling reactions. The main intermediate generated during TCH photodegradation was explored by HPLC-MS. Besides, the direct Z-scheme photocatalytic mechanism was confirmed by band position analysis, electron spin resonance (ESR) and active species capture experiment. 相似文献
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14.
Multimedia Tools and Applications - We present three stages of a novel backgrounds subtraction method in this paper: a new pixel-block based randomized arrangement is utilized to preprocess all the... 相似文献
15.
Shuaiqi Meng Dr. Jia Guo Dr. Kaili Nie Prof. Tianwei Tan Haijun Xu Prof. Luo Liu 《Chembiochem : a European journal of chemical biology》2019,20(17):2232-2235
Fatty acids are versatile precursors for fuels, fine chemicals, polymers, perfumes, etc. The properties and applications of fatty acid derivatives depend on chain length and on functional groups and their positions. To tailor fatty acids for desired properties, an engineered P450 monooxygenase has been employed here for enhanced selective hydroxylation of fatty acids. After oxidation of the hydroxy groups to the corresponding ketones, Baeyer–Villiger oxidation could be applied to introduce an oxygen atom into the hydrocarbon chains to form esters, which were finally hydrolyzed to afford either hydroxylated fatty acids or dicarboxylic fatty acids. Using this strategy, we have demonstrated that the high-value-added flavors exaltolide and silvanone supra can be synthesized from stearic acid through a hydroxylation/carbonylation/esterification/hydrolysis/lactonization reaction sequence with isolated yields of about 36 % (for ω−1 hydroxylated stearic acid; 100, 60, 80, 75 % yields for the individual reactions, respectively) or 24 % (for ω−2 hydroxylated stearic acid). Ultimately, we obtained 7.91 mg of exaltolide and 13.71 mg of silvanone supra from 284.48 mg stearic acid. 相似文献
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17.
Cheng-Jun Tan Chuan-Xiang Tang Wen-Hui Huang Qing-Xiu Jin Ying-Chao Du Qun Luo Pei-Dong Wu Dong-Hai Liu Lu-Ming Zhang Cong Xu 《核技术(英文版)》2019,30(3)
Distributed X-ray sources comprise a single vacuum chamber containing multiple X-ray sources that are triggered and emit X-rays at a specific time and location. This process facilitates an application for innovative system concepts in X-ray and computer tomography. This paper proposes a novel electron beam focusing, shaping,and deflection electron gun for distributed X-ray sources.The electron gun uses a dispenser cathode as an electron emitter, a mesh grid to control emission current, and two electrostatic lenses for beam shaping, focusing, and deflection. Novel focusing and deflecting electrodes were designed to increase the number of focal spots in the distributed source. Two identical half-rectangle opening electrodes are controlled by adjusting the potential of the two electrodes to control the electron beam trajectory, and then, multifocal spots are obtained on the anode target. The electron gun can increase the spatial density of the distributed X-ray sources, thereby improving the image quality. The beam experimental results show that the focal spot sizes of the deflected(deflected amplitude 10.5 mm)and non-deflected electron beams at full width at half maximum are 0.80 mm 90.50 mm and 0.55 mm 90.40 mm, respectively(anode voltage 160 kV; beam current 30 mA). The imaging experimental results demonstrate the excellent spatial resolution and time resolution of an imaging system built with the sources, which has an excellent imaging effect on a field-programmable gate array chip and a rotating metal disk. 相似文献
18.
针对井下瓦斯抽采中原放水器配气阀安装不规范、双截止阀使用繁琐、工人劳动强度大等现状,研制了具有集成调控装置的放水器,能够实现一个阀门控制所有气路和水路,自主放水和负压排水,从源头上杜绝了瓦斯喷孔和水流溢出等情况,大大降低了职工的劳动强度,实现了井下抽采系统安全可靠运行。 相似文献
19.
研究了轧制变形量及退火温度对T9S钛合金板材显微组织和室温力学性能的影响。结果表明:增加成品轧制变形量,板材组织破碎更充分,退火后形成等轴α相、拉长α相和晶间β相组织形貌,变形流线比较明显,板材室温强度和硬度升高,伸长率降低,弹性模量增加。随着退火温度升高,板材室温强度和硬度逐渐降低,伸长率逐渐提高,横向弹性模量逐渐减小,纵向弹性模量先增加后减小。经(750~790) ℃×45 min空冷退火处理后的板材可以获得较好的强度和塑性的匹配。 相似文献
20.
Yajun Zhang Shan Liu Jing Tan Guoyin Jiang Qing Zhu 《International Journal of Project Management》2018,36(4):627-639
Although business process outsourcing (BPO) can reduce cost and enhance the competitiveness of firms, the implementation of BPO projects is unsatisfactory. By integrating knowledge management capability theory and risk-based view, we develop a model of how different types of BPO risks affect project satisfaction and how knowledge management capability changes the influences of BPO risks. A survey of 121 BPO projects was conducted among BPO client department manager and project manager through a pairwise design. Empirical evidence reveals that social system, technical system, and project management risks negatively affect BPO project satisfaction. However, cultural, technological, and structural levels of knowledge management capabilities weaken the negative risk effects of social system, technical system, and project management, respectively. Different types of risks and knowledge management capabilities should be matched to achieve effective risk management. 相似文献