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161.
Surface Energy and Surface Stability of Ag Nanocrystals at Elevated Temperatures and Their Dominance in Sublimation‐Induced Shape Evolution
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Long‐Bing He Lei Zhang Xiao‐Dong Tan Lu‐Ping Tang Tao Xu Yi‐Long Zhou Zhan‐Yong Ren Yun Wang Chun‐Yu Teng Li‐Tao Sun Jian‐Feng Nie 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(27)
The surface energy and surface stability of Ag nanocrystals (NCs) are under debate because the measurable values of the surface energy are very inconsistent, and the indices of the observed thermally stable surfaces are apparently in conflict. To clarify this issue, a transmission electron microscope is used to investigate these problems in situ with elaborately designed carbon‐shell‐capsulated Ag NCs. It is demonstrated that the {111} surfaces are still thermally stable at elevated temperatures, and the victory of the formation of {110} surfaces over {111} surfaces on the Ag NCs during sublimation is due to the special crystal geometry. It is found that the Ag NCs behave as quasiliquids during sublimation, and the cubic NCs represent a featured shape evolution, which is codetermined by both the wetting equilibrium at the Ag–C interface and the relaxation of the system surface energy. Small Ag NCs (≈10 nm) no longer maintain the wetting equilibrium observed in larger Ag NCs, and the crystal orientations of ultrafine Ag NCs (≈6 nm) can rotate to achieve further shape relaxation. Using sublimation kinetics, the mean surface energy of Ag NCs at 1073 K is calculated to be 1.1–1.3 J m?2. 相似文献
162.
Polypyrrole Whelk‐Like Arrays toward Robust Controlling Manipulation of Organic Droplets Underwater
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Xianyong Lu Zhuang Kong Guozheng Xiao Chao Teng Yunan Li Guangyuan Ren Shuangbao Wang Ying Zhu Lei Jiang 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(40)
Whelk‐like polypyrrole (PPy) arrays film is successfully prepared by electropolymerization of pyrrole in the presence of low‐surface‐energy tetraethylammonium perfluorooctanesulfonate (TEAPFOS) as dopant. The underwater wettability of PPy whelk‐like arrays can be successfully tuned by electrical doping/dedoping of PFOS ions. Interestingly, CCl4 droplets with microliter‐size as a representative sample are gathered together to form a larger droplet underwater at the potential of +0.8 V (vs Ag/AgCl), because PPy is in its PFOS‐doped states. Note that CCl4 droplet can climb uphill successfully on the inclined whelk‐like arrays PPy film under the applied potential of ?1.0 V (vs Ag/AgCl), which may be attributed to wettability gradient derived from different oxidation states of PPy induced by electrochemical potential. These results may provide a simple strategy for on‐demand manipulation of organic droplets underwater at low voltage. 相似文献
163.
Xinghua Chang Teng Wang Zhiliang Liu Xinyao Zheng Jie Zheng Xingguo Li 《Nano Research》2017,10(6):1950-1958
We report a simple method of preparing a high performance,Sn-based anode material for lithium ion batteries (LIBs).Adding H2O2 to an aqueous solution containing Sn2+ and aniline results in simultaneous polymerization of aniline and oxidation of Sn2+ to SnO2,leading to a homogeneous composite of polyaniline and SnO2.Hydrogen thermal reduction of the above composite yields N-doped carbon with hierarchical porosity and homogeneously distributed,ultrafine Sn particles.The nanocomposite exhibits excellent performance as an anode material for lithium ion batteries,showing a high reversible specific capacity of 788 mAh·g-1 at a current density of 100 mA·g-1 after 300 cycles and very good stability up to 5,000 mA·g-1.The simple preparation method combined with the good electrochemical performance is highly promising to promote the application of Sn based anode materials. 相似文献
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Space-filling and projective properties of design of computer experiments methods are desired features for metamodelling. To enable the production of high-quality sequential samples, this article presents a novel deterministic sequential maximin Latin hypercube design (LHD) method using successive local enumeration, notated as sequential-successive local enumeration (S-SLE). First, a mesh-mapping algorithm is proposed to map the positions of existing points into the new hyper-chessboard to ensure the projective property. According to the maximin distance criterion, new sequential samples are generated through successive local enumeration iterations to improve the space-filling uniformity. Through a number of comparative studies, several appealing merits of S-SLE are demonstrated: (1) S-SLE outperforms several existing LHD methods in terms of sequential sampling quality; (2) it is flexible and robust enough to produce high-quality multiple-stage sequential samples; and (3) the proposed method can improve the overall performance of sequential metamodel-based optimization algorithms. Thus, S-SLE is a promising sequential LHD method for metamodel-based optimization. 相似文献
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168.
YongTai Zhang Kai Zhang Zhe Li HongYu Zhang Teng Guo YanYan Li JiHui Zhao NianPing Feng 《IET nanobiotechnology / IET》2018,12(8):1037
The main objective of this work was to investigate the uptake channels of skin cells through which coumarin 6, transported by deoxycholate‐mediated liposomes (DOC‐LS), was internalised; this was also compared against the action of conventional LS. Coumarin 6‐loaded DOC‐LS and LS were characterised for size distribution, zeta potential, and shape, and analysed in vitro in human epidermal immortal keratinocyte (HaCaT) (epidermal) and human embryonic skin fibroblast (CCC‐ESF‐1) (dermal) cell lines. Various endocytosis inhibitors were incubated with cells treated with the nanocarriers. Flow cytometry results indicated that HaCaT and CCC‐ESF‐1 cells internalise the tested preparations through pinocytotic vesicles, macropinocytosis, clathrin‐mediated endocytic pathways, and via lysosomes, which consume a considerable amount of energy. The endocytosis pathways of DOC‐LS and LS showed no difference. This study provides a basis for the application of LS being combined with a microneedle system for efficient intracellular drug delivery, targeting cutaneous histocyte disorders.Inspec keywords: drugs, nanoparticles, lipid bilayers, nanomedicine, biomedical materials, electrokinetic effects, biomembrane transport, drug delivery systems, skin, organic compoundsOther keywords: dermal delivery, CCC‐ESF‐1 cells, skin cells, deoxycholate‐mediated liposomes, coumarin 6‐loaded DOC‐LS, endocytosis inhibitors, clathrin‐mediated endocytic pathways, endocytosis pathways, HaCaT cell lines, size distribution, zeta potential, nanocarriers, flow cytometry, pinocytotic vesicles, macropinocytosis, microneedle system, efficient intracellular drug delivery, targeting cutaneous histocyte disorders 相似文献
169.
张力控制是光纤弹性材料缠绕工艺中的一项关键技术,它直接影响到缠绕制品的质量,因此提出一种基于线速度差张力产生原理、交流伺服电机和微特直流力矩电机为施力机构的复合张力控制系统总体方案,实现对张力的精密控制;在对复合张力控制系统进行了建模分析基础上,模拟真实光纤环缠绕环境,采用模糊控制策略,仿真验证了复合张力控制系统的控制效果,表明复合张力模糊控制系统具有响应快、超调量小及精度高的优点。 相似文献
170.
目的 研究沿面介质阻挡放电(Surface Dielectric Barrier Discharge,SDBD)等离子体对生鲜鸡胸肉的杀菌作用及品质影响。方法 采用放电功率为260 W的SDBD等离子体分别处理生鲜鸡胸肉2 min和4 min,并于4 ℃贮藏12 d。每隔3 d取样,测定菌落总数、色泽、pH、汁液流失率、硫代巴比妥酸反应物(Thiobarbituric Acid Reactive Substances,TBARS)含量、挥发性盐基氮(Total Volatile Basic Nitrogen,TVB-N)含量及质构特性。结果 经SDBD等离子体处理2 min或4 min,并于4 ℃贮藏12 d后,生鲜鸡胸肉的菌落总数分别为7.16 lg(CFU/g)和6.70 lg(CFU/g),均低于对照组样品的菌落总数(7.55 lg(CFU/g))。此外,SDBD等离子体处理能够显著(P<0.05)改善冷藏期间鸡胸肉的品质参数,如pH、色泽(L*、a*和b*)、汁液流失率、TVB–N含量和质构特性(硬度、弹性、咀嚼性等),但对脂质氧化具有促进作用。结论 SDBD等离子体对生鲜鸡胸肉具有良好的杀菌效果,并有效保持了其品质,在鸡胸肉保鲜上具有巨大的应用前景。 相似文献