Revealing structural isomerism in nanoparticles using single-crystal X-ray crystallography remains a largely unresolved task, although it has been theoretically predicted with some experimental clues. Here we report a pair of structural isomers, Au38T and Au38Q, as evidenced using electrospray ionization mass spectrometry, X-ray photoelectron spectroscopy, thermogravimetric analysis and indisputable single-crystal X-ray crystallography. The two isomers show different optical and catalytic properties, and differences in stability. In addition, the less stable Au38T can be irreversibly transformed to the more stable Au38Q at 50 °C in toluene. This work may represent an important advance in revealing structural isomerism at the nanoscale.

Controlling the dopant type, number, and position in doped metal nanoclusters (nanoparticles) is crucial but challenging. In the work described herein, we successfully achieved the mono-cadmium doping of Au25 nanoclusters, and revealed using X-ray crystallography in combination with theoretical calculations that one of the inner-shell gold atoms of Au25 was replaced by a Cd atom. The doping mode is distinctly different from that of mono-mercury doping, where one of the outer-shell Au atoms was replaced by a Hg atom. Au24Cd is readily transformed to Au24Hg, while the reverse (transformation from Au24Hg to Au24Cd) is forbidden under the investigated conditions.

We prepare a series of MAg 24 (SR) 18 (M = Ag/Pd/ Pt/Au) nanoclusters (NCs) with similar core−inner shell−outer shell structures and investigate their crystal and solution photoluminescence. The core silver atom replacement by the Pd/Pt/Au atom obviously tunes the geometric and electronic structures of Ag 25 (SR) 18 NC. The crystal photoluminescence intensities sequence hints a core-atom-directing charge transfer from the ligands to the metal kernels. Both the calculated NPA charge and the measured Ag inner shell −S terminal bond length support the proposed mechanism. Further experiments show the solvent influence on the NCs photoluminescence supported by the blue-shift of emissions of MAg 24 (SR) 18 NCs and the solvent-dependent photoluminescence intensity sequences. Especially, for PtAg 24 (SR) 18 , the quantum yield is almost 100-fold greater in CH 3 CN (18.6%) than in CH 2 Cl 2 (0.2%). However, the emission wavelengths of the series of NCs are barely influenced by the solvent type. This work indicates the importance of the core atom and the solvent to the photoluminescence of core−inner shell−outer shell silver NCs, having important implications for the photoluminescence mechanisms and tuning of noble metal nanoparticles.

Herein we report three important results of widespread interest, which are (1) the crystal structure of [Au24Pt(PET)18](0), (2) the crystal structure of [Au24Pd(PET)18](0) and (3) the main source of magnetism in [Au25(PET)18](0).

No abstract

To reduce the uncertain influence of wind power and solar photovoltaic power on virtual power 11 plant (VPP) operation, robust optimization theory (ROT) is introduced to build a stochastic scheduling 12 model for VPP considering the uncertainty, price-based demand response (PBDR) and incentive-based 13 demand response (IBDR). First, the VPP components are described including the wind power plant (WPP), 14 photovoltaic generators (PV), convention gas turbine (CGT), energy storage systems (ESSs) and demand 15 resource providers (DRPs). Then, a scenario generation and reduction frame is proposed for analyzing and 16 simulating output stochastics based on the interval method and the Kantorovich distance. Second, a 17 bi-level robust scheduling model is proposed with a double robust coefficient for WPP and PV. In the 18 upper layer model, the maximum VPP operation income is taken as the optimization objective for building 19 the scheduling model with the day-ahead prediction output of WPP and PV. In the lower layer model, the 20 day-ahead scheduling scheme is revised with the actual output of the WPP and PV under the objectives of 21 the minimum system net load and the minimum system operation cost. Finally, the independent micro-grid 22 in a coastal island in eastern China is used for the simulation analysis. The results illustrate that the model 23 can overcome the influence of uncertainty on VPP operations and reduce the system power shortage cost 24 by connecting the day-ahead scheduling with the real-time scheduling. ROT could provide a flexible 25 decision tool for decision makers, effectively addressing system uncertainties. ESSs could replace CGT to 26 provide backup service for the WPP and PV, to smooth the VPP output curve and to improve the WPP and 27 © 2016. This manuscript version is made available under the Elsevier user license http://www.elsevier.com/open-access/userlicense/1.0/ PV grid connection by its charging-discharging characteristics. Meanwhile, IBDR and PBDR could 28 smooth the load curve to the maximum extent, link the generation side with the demand side to minimize 29 abandoned power value and reach the optimum benefit of VPP operation. 30 1 Introduction 32 Since energy and environmental problems become very serious, distributed energy resources (DERs), 33 especially wind power and solar photovoltaic power, are playing increasingly important roles in the energy 34 structure. However, constraints of small installed capacity, intermittence, uncertainty and other 35 characteristics, make entrance and operation of the power market difficult for DERs[1]. Thus, the virtual 36 power plant (VPP) was proposed as a new technology for DERs in the power market [2]. Without changing 37 the DERs grid connection method, VPP integrates different types of DERs, such as distributed power 38 sources, energy storage systems and controllable loads, by using advanced control, calculation and 39 communication technology [3]. In recent years, smart grid technology has gained significant attention. The 40 government...

Doped nanoparticles (especially bimetal doped nanoparticles) have attracted extensive interest not only for fundamental scientific research but also for application purposes. However, their indefinite composition (structure) and broad distribution hinder an insightful understanding of the interaction between these invasive metals in bimetal doped nanoparticles. Fortunately, atom-precise bimetal doped ultrasmall nanoparticles (nanoclusters) provide opportunities to obtain such insights. However, atom-precise trimetal nanoclusters and their structures have rarely been reported. Here, we successfully dope thiolated Au 25 nanoclusters with Hg and Ag successively by using a biantigalvanic reduction method. We then fully characterize the as-obtained trimetal nanoclusters using multiple techniques (including single-crystal X-ray crystallography), and we demonstrate that the mercury and silver dopings exhibit not only a synergistic but also a counteractive influence on some of the physicochemical properties of Au 25 .

While the role of drug resistance mutations in HIV protease has been studied comprehensively, mutations in its substrate, Gag, have not been extensively cataloged. Using deep sequencing, we analyzed a unique collection of longitudinal viral samples from 93 patients who have been treated with therapies containing protease inhibitors (PIs). Due to the high sequence coverage within each sample, the frequencies of mutations at individual positions were calculated with high precision. We used this information to characterize the variability in the Gag polyprotein and its effects on PI-therapy outcomes. To examine covariation of mutations between two different sites using deep sequencing data, we developed an approach to estimate the tight bounds on the two-site bivariate probabilities in each viral sample, and the mutual information between pairs of positions based on all the bounds. Utilizing the new methodology we found that mutations in the matrix and p6 proteins contribute to continued therapy failure and have a major role in the network of strongly correlated mutations in the Gag polyprotein, as well as between Gag and protease. Although covariation is not direct evidence of structural propensities, we found the strongest correlations between residues on capsid and matrix of the same Gag protein were often due to structural proximity. This suggests that some of the strongest inter-protein Gag correlations are the result of structural proximity. Moreover, the strong covariation between residues in matrix and capsid at the N-terminus with p1 and p6 at the C-terminus is consistent with residue-residue contacts between these proteins at some point in the viral life cycle.