The paper reports an island nucleation and secondary growth of aligned ZnO:Cu nanorod arrays
via
thermal vapor phase transport. Results analysis indicates that the secondary segment is epitaxially ...grown on the ZnO:Cu nanorods with the radius strongly dependent on temperature and the concentration of zinc vapor. The modified characteristic radius (
R
c
) model is used to explain the nucleation and secondary growth process. Temperature-dependent photoluminescence spectra indicate that the band gap emission of the secondary growth nanorods is greatly restrained. A controversial 3.31 eV emission (A line) and two different donoracceptor pair (DAP) recombinations at 3.24 eV and 2.48 eV are observed at 13 K. The A line shows a different behavior from the two DAP emissions during the heat-up process. Intrinsic room temperature ferromagnetism (RTFM) is observed in the secondary growth ZnO:Cu nanorods and it can be explained by oxygen vacancy and copper defects related to bound magnetic polar (BMP) or double exchange mechanism.
Island nucleation on ZnO:Cu nanorod arrays is observed, and characterization results of the secondary growth ZnO:Cu nanorod arrays show strong green emission and two donoracceptor pair recombinations with intrinsic room temperature ferromagnetism.
Due to its outstanding photo-catalysis properties, low-dimensional V2O5 has many important applications in lithium ion batteries, supercapacitors, electrochromic devices, photocatalysts, sensors, et ...al. As good photocatalysts for organic pollutants, some key issues of photocatalysts are charge generation, separation, transfer of nanocomposites under irradiation of visible light. To improve their important properties and pave the effective conductive channels for charge transfer and separation, low-dimensional V2O5/graphene nanoribbons nanocomposites were prepared. The emphasis is put on adsorption response to VOC of nanocomposite based on the QCM (quartz crystal microbalance) device. In order to investigate the mechanism of charge-generated by visible light, the photoconductivity response to visible light and 808 nm laser with low-power were studied based on interdigital electrodes of Au on flexible PET (polyethylene terephthalate) film substrate. Some good results were obtained. This illustrates that this nanocomposite can easily produce the charge-generate with visible light and 808 nm laser with low-power, avoiding the recombination of charge-generate by light. It would be good applications in remove the organic pollutants with photocatalysis effects.
In order to enhance the quality of woodwork, a new drying equipment of two-stage compression high temperature heat pump was developed. This heat pump drying equipment is capable of switching between ...one-stage compression and two-stage compressing. Components and working principle of two-stage compression high temperature heat pump equipment were introduced in this study. Drying experiment was conducted with Pinus massoniana plates. The results show that this equipment had great energy saving performance and the average energy recycling rate could be achieved beyond 28%. Meanwhile, by means of two-stage compression and utilization of new refrigerant-R245fa, condensing temperature and heating temperature reach 120 and 110°C, respectively.
Many factors affect the photoluminescence (PL) of graphene oxide (GO). The influence of Mn super(2+) on the PL in GO was systematically investigated when the universal heteroion was introduced in the ...common preparation based on the Hummers method, and for the first time we propose that a Mn super(2+) mediated energy transfer process may be a versatile origin in GO.
Five new platinum(II) complexes (1-5) with 4-toluenesulfonyl-L-amino acid dianion and 2,2′-bipyridine (bipy) have been synthesized and characterized by elemental analysis, IR, UV,
1
H-NMR,
13
C-NMR, ...and mass spectra. The crystal structure of 1 has been determined by X-ray diffraction analysis. Cytotoxicity was tested by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and sulforhodamine B (SRB) assays. The results indicate that 1-5 exert cytotoxic effects with selectivity against tested carcinoma cell lines; 5 displays better cytotoxicity against BGC-823, Bel-7402, and KB cell lines, while 1 has better cytotoxicity against KB cell line. The 4-toluenesulfonyl- L-amino acid dianions have important effects on cytotoxicity; when 4-toluenesulfonyl-L-amino acid dianions are 4-toluenesulfonyl-L-glycine and 4-toluenesulfonyl-L-phenylalanine, the complexes show better cytotoxicity.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
With virtual machine (VM) technology being increasingly mature, computing resources in modern Cloud systems can be partitioned in fine granularity and allocated on demand with "pay-as-you-go" model. ...In this work, we study the resource query and allocation problems in a Self-Organizing Cloud (SOC), where host machines are connected by a peer-to-peer (P2P) overlay network on the Internet. To run a user task in SOC, the requester needs to perform a multi-dimensional range search over the P2P network for locating host machines that satisfy its minimal demand on each type of resources. The multi-dimensional range search problem is known to be challenging as contentions along multiple dimensions could happen in the presence of the uncoordinated analogous queries. Moreover, low resource matching rate may happen while restricting query delay and network traffic. We design a novel resource discovery protocol, namely Proactive Index Diffusion CAN (PID-CAN), which can proactively diffuse resource indexes over the nodes and randomly route query messages among them. Such a protocol is especially suitable for the range query that needs to maximize its best-fit resource shares under possible competition along multiple resource dimensions. Via simulation, we show that PID-CAN could keep stable and optimized searching performance with low query delay and traffic overhead, for various test cases under different distributions of query ranges and competition degrees. It also performs satisfactorily in dynamic node-churning situation.
Momentum: A New Look on the Old World Zhang, Haoran; Tang, Zihe; Sun, Luwei
Proceedings of the 2022 6th International Conference on E-Business and Internet,
10/2022
Conference Proceeding
With the rapid growth of the stock market, many researchers examined the profitability and market efficiency of various trading strategies with the idea of Momentum Investing. This study optimizes ...the Moving Average Convergence-Divergence (MACD) oscillator and tests its performance under different trading strategies. The research simulates the trading process of 40 U.S. industry portfolios from 1926 to 2021 using different MACD oscillators constructed by the Exponential Moving Average (EMA) indicators of different decay parameters. To acquire the optimal MACD oscillator, the study performs the OLS linear regression analysis on each industry's stimulated excess returns and excess industry portfolio returns and uses the corresponding regression coefficients (alpha and beta) as the assessment criteria of the performance. To further optimize the model, the study improves the traditional trading strategy, the simple-crossover operation, to the n-day holding strategy, which aims to weaken the influence of false signals. The result shows that MACD strategies generally have positive alpha, hinting that investor can utilize this indicator to diversify portfolios and hedge their risks.
Recommender systems have made significant strides in various industries, primarily driven by extensive efforts to enhance recommendation accuracy. However, this pursuit of accuracy has inadvertently ...given rise to echo chamber/filter bubble effects. Especially in industry, it could impair user's experiences and prevent user from accessing a wider range of items. One of the solutions is to take diversity into account. However, most of existing works focus on user's explicit preferences, while rarely exploring user's non-interaction preferences. These neglected non-interaction preferences are especially important for broadening user's interests in alleviating echo chamber/filter bubble effects. Therefore, in this paper, we first define diversity as two distinct definitions, i.e., user-explicit diversity (U-diversity) and user-item non-interaction diversity (N-diversity) based on user historical behaviors. Then, we propose a succinct and effective method, named as Controllable Category Diversity Framework (CCDF) to achieve both high U-diversity and N-diversity simultaneously. Specifically, CCDF consists of two stages, User-Category Matching and Constrained Item Matching. The User-Category Matching utilizes the DeepU2C model and a combined loss to capture user's preferences in categories, and then selects the top-K categories with a controllable parameter K. These top-K categories will be used as trigger information in Constrained Item Matching. Offline experimental results show that our proposed DeepU2C outperforms state-of-the-art diversity-oriented methods, especially on N-diversity task. The whole framework is validated in a real-world production environment by conducting online A/B testing. The improved conversion rate and diversity metrics demonstrate the superiority of our proposed framework in industrial applications. Further analysis supports the complementary effects between recommendation and search that diversified recommendation is able to effectively help users to discover new needs, and then inspire them to refine their demands in search.
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