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排序方式: 共有362条查询结果,搜索用时 15 毫秒
51.
Antony Forster Raj M. Joseph Sekhar S. 《Journal of Thermal Analysis and Calorimetry》2019,136(1):355-365
Journal of Thermal Analysis and Calorimetry - Domestic refrigerators have become an indispensable part of the modern life. Since they are connected to the electric mains and operate throughout the... 相似文献
52.
Allard S Forster M Souharce B Thiem H Scherf U 《Angewandte Chemie (International ed. in English)》2008,47(22):4070-4098
The cost-effective production of flexible electronic components will profit considerably from the development of solution-processable, organic semiconductor materials. Particular attention is focused on soluble semiconductors for organic field-effect transistors (OFETs). The hitherto differentiation between "small molecules" and polymeric materials no longer plays a role, rather more the ability to process materials from solution to homogeneous semiconducting films with optimal electronic properties (high charge-carrier mobility, low threshold voltage, high on/off ratio) is pivotal. Key classes of materials for this purpose are soluble oligoacenes, soluble oligo- and polythiophenes and their respective copolymers, and oligo- and polytriarylamines. In this context, micro- or nanocrystalline materials have the general advantage of somewhat higher charge-carrier mobilities, which, however, could be offset in the case of amorphous, glassy materials by simpler and more reproducible processing. 相似文献
53.
Gaspard S Forster M Huber C Zafiu C Trettenhahn G Kautek W Castillejo M 《Physical chemistry chemical physics : PCCP》2008,10(40):6174-6181
The large intensities available with femtosecond (fs) laser pulses allow permanent structural modifications in transparent materials with high spatial resolution. Irradiation of self-standing transparent biopolymer films, such as collagen, pure and curcumin doped gelatine employing a 60-fs high-power 11 MHz Ti-Sapphire oscillator laser system linked to an optical microscope led to modifications and ablation. Swelling modifications consisting in the foaming of the irradiated area and formation of a single layer of bubbles arranged around the narrow ablation crater were investigated by optical, scanning force (SFM) and scanning electron (SEM) microscopy. These modifications occur at fluences below the respective ablation thresholds, i.e. ablation processes take place on modified swelled phases. The results are discussed in terms of local temperature increase, generation of thermoelastic stress, physico-chemical effects, and in terms of an incubation model, i.e. the accumulation of these phenomena upon successive pulse irradiation. 相似文献
54.
A.?I.?DanilovEmail author R.?R.?Nazmutdinov T.?T.?Zinkicheva E.?B.?Molodkina A.?V.?Rudnev Yu.?M.?Polukarov J.?M.?Feliu 《Russian Journal of Electrochemistry》2008,44(6):697-708
Mechanism of copper underpotential deposition at stepped faces of platinum single crystals Pt(hkl) is studied using cyclic voltammetry, scanning probe microscopy, and quantum-chemical modelling. It is shown that the first stage of UPD is one-dimensional decoration of the (100)- or (110)-orientated steps, then copper monolayer forms at (111)-terraces. The final stage is the secondary step decoration. Quantum-chemical modelling, with the using of long-distance potentials of the Cu-Pt and Cu-Cu pair interactions, allows estimating the energy of copper adsorption at different structure elements of the substrate (steps, kinks, terraces) and revealing the succession of the adatom monolayer formation; it also provides additional information for the identifying of the nature of voltametric peaks for different stages of the copper adsorption-desorption. 相似文献
55.
Two‐Dimensional Core‐Shelled Porous Hybrids as Highly Efficient Catalysts for the Oxygen Reduction Reaction
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Kai Yuan Dr. Xiaodong Zhuang Haiyan Fu Dr. Gunther Brunklaus Dr. Michael Forster Prof. Dr. Yiwang Chen Prof. Dr. Xinliang Feng Prof. Dr. Ullrich Scherf 《Angewandte Chemie (International ed. in English)》2016,55(24):6858-6863
Two‐dimensional (2D) transition‐metal dichalcogenides (TMDs) have drawn much attention due to their unique physical and chemical properties. Using TMDs as templates for the generation of 2D sandwich‐like materials with remarkable properties still remains a great challenge due to their poor solvent processability. Herein, MoS2‐coupled sandwich‐like conjugated microporous polymers (M‐CMPs) with high specific surface area were successfully developed by using functionalized MoS2 nanosheets as template. As‐prepared M‐CMPs were further used as precursors for preparation of MoS2‐embedded nitrogen‐doped porous carbon nanosheets, which were revealed as novel electrocatalysts for oxygen reduction reaction with mainly four‐electron transfer mechanism and ultralow half‐wave potential in comparison with commercial Pt/C catalyst. Our strategy to core–shelled sandwich‐like hybrids paves a way for a new class of 2D hybrids for energy conversion and storage. 相似文献
56.
57.
Eight phenolic compounds, including two mixtures of two compounds, were isolated from the ethyl acetate extract of leaves and stems of Homalium brachybotrys. They were identified on the basis of spectroscopic data as quercetin-3-O-beta-glucopyranoside, luteolin-7-O-beta-glucopyranoside, 5,6-dihydro-6-beta-glucopyranosyloxy-3-(hydroxyphenyl-methyl)-2(4H)-benzofuranone (cochinolide 6-O-beta-glucopyranoside) (1), 2-(6-benzoyl-beta-glucopyranosyloxy)-5-hydroxybenzyl alcohol (poliothrysoside) (2), 2-(beta-glucopyranosyloxy)-5-hydroxybenzyl alcohol (salirepin) (3), 4,5-dihydro-7a-beta-glucopyranosyloxy-3-(hydroxyphenylmethyl)-2(7aH)-benzofuranone (isocochinolide-7a-O-beta-glucopyranoside) (4), 5,6-dihydro-3-(hydroxyphenylmethyl)-2(4H)-benzofuranone (6-deoxycochinolide) (5) and 3-benzylidine-6-hydroxy-2-benzofuranone (1'deoxy-4,5,6-dehydrocochinolide) (6). Benzofuranones (4), (5) and (6) are new natural products. The compounds isolated support the argument that Homalium is best placed in the Salicaceae s.l. 相似文献
58.
非线性涡黏性系数模型和代数应力模型联系了线性涡黏性系数湍流模型和完整的微分
雷诺应力模型.随着它们受到日益关注,其形式也越来越多样化.本篇综述的目的是对这些模
型加以总结并比较它们之间的共同点及不同之处,指出它们与完整微分雷诺应力模型之间的
关系,以及相对于线性涡黏性系数模型而言它们在预报流场上所具有的优势. 相似文献
59.
Heinz‐Georg Nothofer Andreas Meisel Tzenka Miteva Dieter Neher Michael Forster Masao Oda Günter Lieser Dessislava Sainova Akio Yasuda Donald Lupo Wolfgang Knoll Ullrich Scherf 《Macromolecular Symposia》2000,154(1):139-148
A series of 9,9‐dialkyl‐poly(fluorene‐2,7‐diyl)s containing linear and branched alkyl substituents with a Mn of up to 200000 g/mol has been synthesized. Moreover, some of the polymers were end capped with a suitable hole transport functionality, such as a triphenylamine derivative, to improve their charge transport properties and to control the molecular weight. The thermal alignment of these novel polymers on a rubbed polyimide layer led to highly anisotropic film formation with dichroic ratios (absorption parallel and perpendicular to the rubbing direction) of up to 26 in absorption and 21 in emission. 相似文献
60.
Impaction of spray droplets on leaves: influence of formulation and leaf character on shatter,bounce and adhesion 总被引:5,自引:0,他引:5
Gary J. Dorr Shuangshuang Wang Lisa C. Mayo Scott W. McCue W. Alison Forster Jim Hanan Xiongkui He 《Experiments in fluids》2015,56(7):143
This paper combines experimental data with simple mathematical models to investigate the influence of spray formulation type and leaf character (wettability) on shatter, bounce and adhesion of droplets impacting with cotton, rice and wheat leaves. Impaction criteria that allow for different angles of the leaf surface and the droplet impact trajectory are presented; their predictions are based on whether combinations of droplet size and velocity lie above or below bounce and shatter boundaries. In the experimental component, real leaves are used, with all their inherent natural variability. Further, commercial agricultural spray nozzles are employed, resulting in a range of droplet characteristics. Given this natural variability, there is broad agreement between the data and predictions. As predicted, the shatter of droplets was found to increase as droplet size and velocity increased, and the surface became harder to wet. Bouncing of droplets occurred most frequently on hard-to-wet surfaces with high-surface-tension mixtures. On the other hand, a number of small droplets with low impact velocity were observed to bounce when predicted to lie well within the adhering regime. We believe this discrepancy between the predictions and experimental data could be due to air layer effects that were not taken into account in the current bounce equations. Other discrepancies between experiment and theory are thought to be due to the current assumption of a dry impact surface, whereas, in practice, the leaf surfaces became increasingly covered with fluid throughout the spray test runs. 相似文献