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Modification of metal surfaces with complex molecules opens interesting opportunities to build additional functionality into these surfaces. In this work, self assembled monolayers (SAMs) based on the same photoswitchable azobenzene motif but with different head groups have been synthesized and their SAMs on Au(111)/Si substrates have been characterized. 3-[(4-phenylazo)phenoxy]propyl thiol (PAPT) and its acetyl group protected analog, 3-[(4-phenylazo)phenoxy]propyl thioacetate (PAPA), have been synthesized. SAMs from PAPT and PAPA have been characterized by infrared (IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), ellipsometry and cyclic voltammetry (CV). The SAM-forming units of both SAMs are the same, as confirmed by IR and XPS, and the SAMs have similar surface coverage, as evidenced by analysis of the reductive desorption peaks in CVs. The tilt angle of the azobenzene moiety was ca. 75° with respect to the surface normal as determined by IR spectroscopy, i.e., the molecules are lying quite flat on the gold surface. Despite similar surface coverages, the CVs for PAPT in aqueous perchlorate solution show a typical perchlorate adsorption peak to gold, whereas the corresponding experiments with PAPA show no perchlorate adsorption at all. In conclusion, SAM formation can lead to an increase in the number of electrochemically accessible surface sites on the final, SAM covered surface. Whether the amount of such sites increases or decreases, depends on the precursor. The precursor most likely affects the adsorption mechanism and thus the atomic surface structure of the metal at the metal/SAM interface. Thus, details of the SAM formation mechanism, which is affected by the precursor used, can have quite strong effects on the electrochemical properties, and likely also electrocatalytic properties, of the resulting modified surface.

Thermally activated ultrafast diffusion, collision, and combination of metal atoms comprise the fundamental processes in synthesizing burgeoning subnanometer metal clusters for a diversity of applications. However, so far, no method has allowed the kinetically controllable synthesis of subnanometer metal clusters without compromising metal loading. Herein, we have developed, for the first time, a graphene-confined ultrafast radiant heating (GCURH) method for the synthesis of high-loading metal cluster catalysts in microseconds, where the impermeable and flexible graphene acts as a diffusion-constrained nanoreactor for high-temperature reactions. Originating from the graphene-mediated ultrafast and efficient laser-to-thermal conversion, the GCURH method is capable of providing a record-high heating and cooling rate of ∼109°C/s and a peak temperature above 2 000°C, and the diffusion of thermally activated atoms was spatially limited within the confinement of graphene nanoreactor. As a result, due to the kinetics-dominant and diffusion-constrained condition provided by GCURH, subnanometer Co cluster catalysts with high metal loading up to 27.1 wt.% have been synthesized by pyrolyzing Co-based metal-organic framework (MOF) in microseconds, representing one of the highest size-loading combinations and the quickest rate for MOF pyrolysis among reported literature. The obtained Co cluster catalyst not only exhibits an extraordinary activity similar to that of its most modern multi-component noble metal counterparts in the electrocatalytic oxygen evolution reaction, but also shows great convenience in catalyst recycling and refining due to its single metal component. Such a novel GCURH technique offers the way for kinetically regulated, limited the diffusion distance of thermally activated atoms, which prepares the way for the development of sophisticated and environmentally sustainable metal cluster catalysts.

Elucidating the interaction between different atomic species of the bimetallic nanoparticles under reaction conditions is key to the design of efficient catalysts. Here, we report a laser-assisted strategy towards PtRu alloy, where isolated Pt sites are anchored on the Ru host, and track the variation of the active site under electrocatalytic conditions. Operando X-ray absorption spectroscopy identified the local environment variations around Pt single atoms and revealed the increased PtRu alloying degree during hydrogen evolution reaction (HER). Theoretical simulations confirmed that the increase of alloying extent modulates the d-band center of Ru for enhancing the activity. Surface-restructured PtRu alloy exhibited outstanding HER activity and stability in all pH, achieving an unexpected low overpotential of only 15, 17, and 28 mV at 10 mA cm-2 in 1 M KOH, 1 M PBS, and 0.5 M H2SO4, respectively. This demonstrates the feasibility of surface engineering for designing advanced bimetallic catalysts with atomic-scale platinum decoration.

Exploring high-efficiency catalysts for the electrochemical hydrogen evolution reaction (HER) in alkaline environments is attractive but remains challenging. Here we report a coordination regulation strategy to tune the atomic structure of Ru cluster catalysts supported on Ti3C2Tx MXene (Ru-Ti3C2Tx) for the HER. We identify that the coordination number (CN) of Ru-Ru could be slightly regulated from 2.1 to 2.8 by adjusting the synthesized temperature so as to achieve an optimal catalytic configuration. The Ru-Ti3C2Tx with a CNRu-Ru of 2.8 exhibits the best catalytic activity with a low overpotential of 96 mV at 10 mA cm-2 and a mass activity about 11.5 times greater than the commercial Pt/C catalyst. Density functional theory calculations demonstrated that the small Ru clusters have a stronger covalent interaction with Ti3C2Tx support leading to an optimal ΔGH* value. This work opens up a general avenue to modulate the coordination environment of catalysts for the HER.

The development of atomically precise dinuclear heterogeneous catalysts is promising to achieve efficient catalytic performance and is also helpful to the atomic-level understanding on the synergy mechanism under reaction conditions. Here, we report a Ni2(dppm)2Cl3 dinuclear-cluster-derived strategy to a uniform atomically precise Ni2 site, consisting of two Ni1-N4 moieties shared with two nitrogen atoms, anchored on a N-doped carbon. By using operando synchrotron X-ray absorption spectroscopy, we identify the dynamically catalytic dinuclear Ni2 structure under electrochemical CO2 reduction reaction, revealing an oxygen-bridge adsorption on the Ni2-N6 site to form an O-Ni2-N6 structure with enhanced Ni-Ni interaction. Theoretical simulations demonstrate that the key O-Ni2-N6 structure can significantly lower the energy barrier for CO2 activation. As a result, the dinuclear Ni2 catalyst exhibits >94% Faradaic efficiency for efficient carbon monoxide production. This work provides bottom-up target synthesis approaches and evidences the identity of dinuclear sites active toward catalytic reactions.

Purpose Leading-edge information and communication technology provides the base to facilitate obtaining, interoperating and federating shared metadata knowledge in collaborative networks from multiple heterogeneous data sources. The purpose of this study is to develop a methodology and a set of mechanisms to support this task in the collaborative environment. Design/methodology/approach In this paper, the authors first identify and capture four main typical sources to find or generate metadata knowledge for shared data in emerging networked environments, including existing well-designed metadata, the typical ones are relational schemas of existing databases in the environment; fragmented metadata sources, i.e. metadata that can be realized from existing mission statements and example application scenarios in the environment, usually characterized by their fragmented, lightweight and behavior-intensive features; extracting metadata for simple labeled unstructured data, e.g. textual communications among its stakeholders; and semantic constraints on metadata, e.g. the temporal data behavior could be generated from governance policies in the environment. Second, the authors introduce their systematic methodology to the unification of the resulted metadata consisting of four semiautomated unification steps that gradually develops and enhances a unified ontology for the environment, formalized in web ontology language. Findings The methodology steps and their corresponding mechanisms are described and exemplified in detail in this paper. Furthermore, this paper presents the outcome of applying the authors’ methodology to an example emerging case through the generation of a unified ontology for that environment. Originality/value The addressed example application area is a real case in the field of higher education in China and therefore serves as a proof of concept and verification of the effectiveness of the authors’ proposed approach.

Actinide-based catalysts have been regarded as promising candidates for N

The development of atomically precise dinuclear heterogeneous catalysts is promising to achieve efficient catalytic performance and is also helpful to the atomic-level understanding on the synergy mechanism under reaction conditions. Here, we report a Ni

Nowadays, many countries are actively seeking ways to solve the energy crisis and environmental pollution. New Energy Vehicle (NEV) has become an important way to solve these problems. With the rapid development of NEV, its batteries need to be replaced with new batteries after 5&ndash, 8 years. Therefore, whether the second use of NEV&rsquo, s battery has commercial or social value becomes a research hotspot. The innovation of this paper is to use the cost-benefit method to determine the value influencing factors of NEV&rsquo, s battery second use, and use system dynamics to perform scenario simulation analysis. The methods used in this paper are the cost-benefit method and system dynamics method. Firstly, this paper systematically analyzes the cost and benefit factors that affect the second use value of China&rsquo, s NEV batteries and uses system dynamics to establish the relationship and value model among various factors. Then, this paper compares the value of battery energy storage between old batteries and new batteries. According to the cost-income factor analysis, this paper eventually selects specific factors and uses VENSIM software to carry out the multi-scenario simulation. The results show that NEV&rsquo, s battery second use has commercial and social value compared to new battery energy storage. Moreover, battery cost, government subsidies, and electricity prices are three important factors that affect the second use value of China&rsquo, s NEV battery. Changing the government&rsquo, s cash subsidy methods, such as providing free batteries or combining new energy to reduce on-grid tariffs, will help increase the second use value of the NEV battery. In the future, the second use value of China&rsquo, s NEV battery industry will be more significant, with the update of the technology, the surge in the number of NEV&rsquo, s used batteries, and government support.

Multi-cloud composed by multiple clouds environment can take advantages of cloud computing which is becoming increasingly popular among new scientific and technological undertakings. The requested services of users could often be distributed across some providers hosted by several clouds. The multi-cloud services composition problem requires new scalable approaches to efficiently perform searching to reduce the energy consumption and monetary cost for fulfilling user's request. In this paper, we present a sustainable strategy for multi-cloud service composition, using Formal Concept Analysis and social network by considering some critical factors such as energy consumption between clouds, monetary cost and trust between users and clouds. In addition, a novel algorithm is proposed regarding to the sustainable multi-cloud service composition. We also evaluated the proposed approach through experiments and the results reveal the feasibility and effectiveness of our approach. Finally, we point out future directions for the selection of cloud providers.

The explosive information growth facilitates the generation of increasingly massive streaming data. As a traditional soft computing approach for data analysis, Formal Concept Analysis (FCA) has the severe problem of low efficiency and long time for coping with massive streaming data. Therefore, devising an optimized efficiency algorithm of FCA for attribute-incremental streaming data is becoming a very urgent and challenging issue. In this paper, a quick algorithm on generating concept lattice for attribute-incremental streaming data is presented. Specifically, the correctness of the proposed algorithm is mathematically proved, and several real-world data sets are utilized in our experiments in order to compare with the existing two FCA algorithms. Experimental results demonstrate that the proposed algorithm significantly improves the efficiency for generating concept lattice of attribute-incremental streaming data. Particularly, the running time could be reduced by approximately 44% for Jazz dataset.

In the process of rapid urbanization, air environment quality has become a hot issue. Aerosol optical depth (AOD) from Moderate Resolution Imaging Spectroradiometer (MODIS) can be used to monitor air pollution effectively. In this paper, the Spearman coefficient is used to analyze the correlations between AOD and urban development, construction factors, and geographical environment factors in Shandong Province. The correlation between AOD and local climatic conditions in Shandong Province is analyzed by geographic weight regression (GWR). The results show that in the time period from 2007 to 2017, the AOD first rose and then fell, reaching its highest level in 2012, which is basically consistent with the time when the national environmental protection decree was issued. In terms of quarterly and monthly changes, AOD also rose first and then fell, the highest level in summer, with the highest monthly value occurring in June. In term of the spatial distribution, the high-value area is located in the northwestern part of Shandong Province, and the low-value area is located in the eastern coastal area. In terms of social factors, the correlation between pollutant emissions and AOD is much greater the correlations between AOD and population, economy, and construction indicators. In terms of environmental factors, the relationship between digital elevation model (DEM), temperature, precipitation, and AOD is significant, but the regulation of air in coastal areas is even greater. Finally, it was found that there are no obvious differences in AOD among cities with different development levels, which indicates that urban development does not inevitably lead to air pollution. Reasonable development planning and the introduction of targeted environmental protection policies can effectively alleviate pollution-related problems in the process of urbanization.

The continuous deterioration of environmental problems and the energy crisis has prompted countries and regions to increase research and development and support for new energy vehicles (NEV). NEV’s battery as the core components play an essential role in the cruising range and manufacturing cost in terms of energy, specific power, new materials, and battery safety. In order to know the development of NEV’s batteries, as well as research hotspots and technology trends, this paper analyses the market performance and technology trend of China NEV’s battery industry. Firstly, this paper analyses the policy and market, then clarify the macro environment of China’s NEV battery industry development. Secondly, this paper uses CITESPACE software to analyze the scientific knowledge of the literature data, such as research hotspots, research institutions, and technology development trends. In the end, this paper proposes policy recommendations for the future development of China’s NEV’s battery industry from the perspectives of technology, market, and industrial chain.

The development of mobile edge computing (MEC) is accelerating the popularity of 5G applications. In the 5G era, aiming to reduce energy consumption and latency, most applications or services are conducted on both edge cloud servers and cloud servers. However, the existing multi-cloud composition recommendation approaches are studied in the context of resources provided by a single cloud or multiple clouds. Hence, these approaches cannot cope with services requested by the composition of multiple clouds and edge clouds jointly in MEC. To this end, this paper firstly expands the structure of the multi-cloud service system and further constructs a multi-cloud multi-edge cloud (MCMEC) environment. Technically, we model this problem with formal concept analysis (FCA) by building the service&ndash, provider lattice and provider&ndash, cloud lattice, and select the candidate cloud composition that satisfies the user&rsquo, s requirements. In order to obtain an optimized cloud combination that can efficiently reduce the energy consumption, money cost, and network latency, the skyline query mechanism is utilized for extracting the optimized cloud composition. We evaluate our approach by comparing the proposed algorithm to the random-based service composition approach. A case study is also conducted for demonstrating the effectiveness and superiority of our proposed approach.

Detecting risk factors during freight period and making prevention or emergency measures is very important for reducing the probability of freight delay. In literatures, the operating time of function is considered as the fatal factor which affect freight period. More time the operation occupy, more important the function. But operating time of function can't reflect primary reason which results in freight delay. In our research, we take risk factors affecting freight period into consideration. From the perspective of transit scenario, we systematically analyze risk factors, mine the relationship among risk factors, and realize the dynamic merge of different freight scenario. This method can truly reflect fundamental factors affecting the freight period. So the management of freight period forewarning can be procedural, fine and dynamic.

To propose a clinically practical and simple fiber tracking method for language pathways, and to explore its feasibility in preoperative planning for brain tumors adjacent to the language cortex.Diffusion tensor imaging was examined in 18 healthy subjects and 13 patients with brain tumors adjacent to the language cortex between December 2013 and June 2014. The associated fibers of language pathways were reconstructed using a commercial software (Syngo workstation). Firstly, the feasibility of fiber tracking method for language pathways in healthy subjects were studied, and then its application was assessed in patients with brain tumors. The anatomic relationship between tumors and the associated fibers was analyzed.By selecting appropriate regions of interest, the associated fibers in the dorsal pathways (superior longitudinal fasciculus/arcuate fasciculus, including both direct and indirect pathways) and ventral pathways (uncinate fasciculus, middle longitudinal fasciculus, inferior longitudinal fasciculus and inferiorfronto-occipital fasciculus) were reconstructed in all 18 healthy subjects. In patients with brain tumors, the relationship between the tumors and adjacent associated fibers were divided into two types: adjacent associated fibers could be displaced or separated, and involved the superior longitudinal fasciculus/arcuate fasciculus (n=6), middle longitudinal fasciculus (n=4), uncinate fasciculus (n=3), inferior longitudinal fasciculus (n=3) and inferiorfronto-occipital fasciculus (n=2); alternatively, the adjacent associated fibers were infiltrated or destroyed, and involved the inferiorfronto-occipital fasciculus (n=10), uncinate fasciculus (n=8), middle longitudinal fasciculus (n=5), inferior longitudinal fasciculus (n=4) and superior longitudinal fasciculus/arcuate fasciculus (n=3).The associated fibers of language pathways could be visualized rapidly and in real-time by fiber tracking technology based on diffusion tensor imaging. This is feasible for preoperative planning regarding brain tumors adjacent to the language cortex.

A flexible inclination measurement system based on wireless sensor network (WSN) is proposed, and the structure of the system, the principle of inclination measurement and the hardware design of the system are described in details. The system that includes accelerometer, MCU, A/D converter and 2.4G wireless transceiver has achieved inclination measurement of high precision in a wide range. Two practical application examples are suggested.

In methanol-aqueous solutions, three novel structure-directing agents (SDAs) were generated in situ and presented. These in situ reactions feature N-methylation transformations between CH3OH solvent and organic cyclic aliphatic and aromatic amines, i.e. 2-methylpiperazine, 1,4-diazabicyclo[2,2,2]octane (dabco) and 3-(aminomethyl)pyridine. Distinct from conventional Eschweiler-Clarke methylation containing excess formic acid and formaldehyde, such a direct methylation transformation from methanol molecules is unique. In the presence of new SDAs, three organically templated zinc phosphites/phosphates, [pmpip][Zn3(HPO3)4] I (pmpip = N,N,N',N'-tetramethyl-2-methylpiperazinium), [dmdabco][Zn3(HPO3)4] II (dmdabco = N,N'-dimethyl-1,4-diazabicyclo[2,2,2]octane) and [Hmampy][Zn2(HPO4)3] III (mampy = N-methyl-3-(aminomethyl)pyridine), have been prepared and structurally characterized by elemental analysis, IR, thermogravimetric analysis, powder and single-crystal X-ray diffraction. Compound I exhibits a 2D layer with eight-membered apertures, compounds II and III possess a 3D interrupted framework with intersecting 8-, 10- and 12-ring channels (for II), and 8-, 10-ring channels (for III), respectively.