Monolayer MoS2 Dendrites on a Symmetry‐Disparate SrTiO3 (001) Substrate: Formation Mechanism and Interface Interaction

Dendritic patterns generated in non‐equilibrium growth processes are prevalent in nature while their formation mechanisms are far from fully understood. Here, we report a coverage‐dependent fractal degree evolution of monolayer 2H‐MoS₂ dendrites synthesized on a symmetry‐disparate substrate of SrTiO₃ (001). Surprisingly, various characterizations have revealed that the monolayer dendrites featured with orthogonal backbones are single crystalline, possessing both peculiar adlayer‐substrate interaction and abnormal indirect bandgap on SrTiO₃ (001). Further theoretical calculations indicate that a prominent diffusion anisotropy of monomer precursors, combined with the disparate adlayer‐substrate symmetry, determine the diffusion‐limited aggregation of MoS₂ towards dendritic shapes. This work provides brand‐new insights in the morphological engineering of two‐dimensional atomic crystals, and contributes greatly to an in‐depth understanding of the detailed dynamics in non‐equilibrium crystal growth.     

Indoline‐Based Molecular Engineering for Optimizing the Performance of Photoactive Thin Films

New indoline dyes ( RK‐1 – 4 ) were designed with a planar geometry and high molar extinction coefficient, which provided surprising power conversion efficiency (PCE) with a thin titanium dioxide film in dye‐sensitized solar cells (DSCs). They had a difference in only alkyl chain length. Despite the same molecular structure, the performance of the respective DSCs varied significantly. Investigating the dye adsorption processes and charge transfer kinetics, the alkyl chain length was determined to affect the dye surface coverage as well as the recombination between the injected photoelectrons and the oxidized redox mediators. When applied to the DSCs as a light harvester, RK‐3 with the dodecyl group exhibited the best photocurrent density, consequently achieving the best PCE of 9.1% with a 1.8 μm active and 2.5 μm scattering layer because of the most favorable charge injection. However, when increasing the active layer thickness, overall device performance deteriorated and the charge collection and regeneration played major roles for determining the PCE. Therefore, RK‐2 featuring the highest surface coverage and moderate alkyl chain length obtained the highest PCEs of 8.8% and 7.9% with 3.5 and 5.1 μm active layers, respectively. These results present a promising perspective of organic dye design for thin film DSCs.     

Improved All‐Polymer Solar Cell Performance by Using Matched Polymer Acceptor

By the introduction of different building blocks and side‐chains, a series of donor–acceptor type polymer acceptors containing naphthalene diimide have been successfully prepared. The theoretical and experimental results show that the molecular design effectively tunes the energy levels, solubility, and coplanarity of the acceptor polymers. The intermolecular packing, which has been considered as a key factor in the bulk heterojunction morphology, has been adjusted by changing the coplanarity. As a result of improved morphology and fine‐tuned energy levels, a power conversion efficiency of 6.0% has been demonstrated for the optimized devices, which is among the highest‐efficiencies for reported all‐polymer solar cells. The improved device performance may be attributed to the resemble crystallinity of the donor/acceptor polymers, which can lead to the optimal phase separation morphology balancing both charge transfer and transport.     

A faulty node detection scheme for wireless sensor networks that use data aggregation for transport

This paper presents a faulty node detection approach for wireless sensor networks that aggregate measurement data on their way toward the sink (base station). The approach is based on the idea of commanding sensor nodes on the aggregation paths to temporarily stop including their readings in the received aggregated readings from their upstream neighbors. The scheme is dependent on the ability of the sink to detect faulty nodes through changes in the received aggregated readings at the sink using a Markov Chain Controller (MCC). The algorithm that is run in the sink uses the MCC to assign a state to each sensor node based on transitions that are triggered by receiving aggregated path readings, and accordingly deduces the nodes that may be faulty. The experimental results show at least 98% detection rate at the cost of reasonable detection delays and generated wireless network traffic. Copyright © 2016 John Wiley & Sons, Ltd.     

面向服务的语义互操作性技术及其标准

面向服务的软件工程面临新的挑战。促进互联网环境中松耦合式服务资源之间的互操作性行为协作,是实现服务资源深度共享与按需服务的关键。文章对服务虚拟化的关键技术：可用资源的服务互操作性封装方法、虚拟化服务组织的互操作性聚合的基于本体的RGPS元建模方法、虚拟化服务管理的互操作性元模型框架及其注册与存储管理、虚拟化服务本体及其与RGPS关联呈现等进行了研究。对研究的互操作性元模型框架（MFI）及ISO系列标准工作新进展进行了介绍。     

钢中合金元素成分起伏对韧脆转变温度的影响

某材料为16MND5的压力容器筒体,在进行低温-20℃冲击试验时,取样位置邻近试样的冲击功却相差很大。通过对冲击功不同的试样分别进行金相检验、断口分析、化学成分分析以及能谱微区成分分析,找出了冲击功相差较大的原因。结果表明:冲击功较低试样中的钼和硅等元素微观聚集程度比冲击功较高试样中的严重,尤其是钼元素的微观聚集更为严重;由于合金元素钼和硅在钢中能提高钢的韧脆转变温度,因此偏聚严重就会导致材料在低温冲击时的冲击功相差较大;由此可以判定是由于热处理工艺不当,造成了钼和硅等合金元素的严重微观聚集,致使材料出现冲击韧度不均匀、相邻位置冲击功相差较大的问题。     

Core-Shell Biopolymer Nanoparticles Produced by Electrostatic Deposition of Beet Pectin onto Heat-Denatured β-Lactoglobulin Aggregates

ABSTRACT:  The purpose of this study was to produce and characterize core-shell biopolymer particles based on electrostatic deposition of an anionic polysaccharide (beet pectin) onto amphoteric protein aggregates (heat-denatured β-lactoglobulin [β-lg]). Initially, the optimum conditions for forming stable protein particles were established by thermal treatment (80 °C for 15 min) of 0.5 wt%β-lg solutions at different pH values (3 to 7). After heating, stable submicron-sized ( d = 100 to 300 nm) protein aggregates could be formed in the pH range from 5.6 to 6. Core-shell biopolymer particles were formed by mixing a suspension of protein aggregates (formed by heating at pH 5.8) with a beet pectin solution at pH 7 and then adjusting the pH to values where the beet pectin is adsorbed (< pH 6). The impact of pH (3 to 7) and salt concentration (0 to 250 mM NaCl) on the properties of the core-shell biopolymer particles formed was then established. The biopolymer particles were stable to aggregation from pH 4 to 6, but aggregated at lower pH values because they had a relatively small ζ-potential. The biopolymer particles remained intact and stable to aggregation up to 250 mM NaCl at pH 4, indicating that they had good salt stability. The core-shell biopolymer particles prepared in this study may be useful for encapsulation and delivery of bioactive food components or as substitutes for lipid droplets.     

酸碱处理对鲢鱼肌原纤维蛋白热变性、聚集、胶凝性质的影响

酸碱法(pH-shifting)提取鱼蛋白是鱼糜加工新丁艺,能提高蛋白得率.酸碱法中极端pH(2.3和11.8)对肌原纤维热变性、热聚集、热致胶凝特性有很大影响.酸碱处理使肌原纤维部分变性,其中酸处理使肌原纤维肌球蛋白完全变性,肌动蛋白变性温度F降(从8l℃降低到77.6℃),碱处理使肌动和肌球变性温度都下降:酸碱处理使肌原纤维发牛聚集,酸处理肌原纤维发牛聚集最严重;酸碱处理使肌原纤维胶凝过程发生明显变化,凝胶强度明显降低,其中酸处理肌原纤维凝胶强度最低(最大储能模量分别为1150、25、135Pa).所以,鱼糜pH-shifting工艺用碱法更合适.