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This paper considers the time difference of arrival (TDOA) and frequency difference of arrival (FDOA) estimation problem for joint localization using unmanned aerial vehicles (UAVs), involving range migration (RM) and Doppler ambiguity within observation interval. A robust estimation method based on interpolation and resampling is proposed. Specifically, the interpolation artificially increases the pulse repetition frequency (PRF). After that, the resampling eliminates the coupling between range frequency and slow time. Finally, a coherent integration step based on inverse discrete Fourier transform (IDFT) is used to achieve parameter estimation and suppress the grating lobes caused by interpolation. The proposed method could be efficiently implemented by fast Fourier transform (FFT), inverse FFT (IFFT) and non-uniform FFT (NUFFT) without parameter searching procedures. Numerical experiments indicate that the proposed method has nearly optimal anti-noise performance but much lower computational complexity than the maximum likelihood estimator, which makes it more competitive in practical applications.

Cr1-xAlxN/CrN/Cr multilayer films with a range of different Al contents were deposited on 9–12% Cr heat-resistant steel using direct current magnetron sputtering (DCMS). The chemical composition, roughness, cross-sectional structure, oxidation resistance and kinetic model of oxidation of the resulting films were investigated using various techniques. We discovered that Al atoms substituted for Cr atoms, while the crystal structure remained unchanged. Since Al doping decreases the lattice constants and hinders grain growth, the roughness of the film decreases, and the microstructure becomes denser, which is beneficial to the enhancement of oxidation resistance. According to the kinetic model, internal diffusion is the main restrictive step in this process. Increasing the Al content aids in the formation of an amorphous oxide surface layer that is abundant in Al. When the Al content is sufficiently high, the diffusion of oxygen into the 9–12% Cr steel substrates is prevented by the oxide surface layer of the film, which protects the substrates from further oxidation.

It is important to understand the changes in microbial properties of plant rhizospheres to elucidate the interaction between heavy metals and plant communities. In this study, high throughput sequencing method was used to analyze the effects of heavy metals on rhizosphere microbial community structure of the autochthonous plant Salsola collina in the Jinchuan mining area. The operational taxonomic units (OTU) number and species diversity, and richness of the bacterial community in the rhizosphere of Salsola collina were higher than those of the bulk soil. Proteobacteria, Actinobacteria, and Firmicutes were the major bacterial phyla, and Salsola collina, Kaistobacter, Citrobacter, Acinetobacter and Pseudomonas were the main genera. Principal component analysis (PCA) and unweighted pair group method using arithmetic average (UPGMA) cluster analysis showed that there were significant differences in bacterial community structure between site and between rhizosphere and bulk soil. The moisture content, total nitrogen, phosphorus, magnesium, nickel, chromium, lead, and zinc contents, and pH had significant effects on species richness of the bacterial community, with total phosphorus content having a significant effect on species diversity. The finding of this study could be used as an important guideline for bioremediation of heavy metals in mining area.

Perfect image compositing can harmonize the appearance between the foreground and background effectively so that the composite result looks seamless and natural. However, the traditional convolutional neural network (CNN)-based methods often fail to yield highly realistic composite results due to overdependence on scene parsing while ignoring the coherence of semantic and structural between foreground and background. In this paper, we propose a framework to solve this problem by training a stacked generative adversarial network with attention guidance, which can efficiently create a high-resolution, realistic-looking composite. To this end, we develop a diverse adversarial loss in addition to perceptual and guidance loss to train the proposed generative network. Moreover, we construct a multi-scenario dataset for high-resolution image compositing, which contains high-quality images with different styles and object masks. Experiments on the synthesized and real images demonstrate the efficiency and effectiveness of our network in producing seamless, natural, and realistic results. Ablation studies show that our proposed network can improve the visual performance of composite results compared with the application of existing methods.

The hot deformation behavior of as-cast 9Cr3W3Co oxide dispersion-strengthened (ODS) steel was investigated by Gleeble 3500 facility in the temperature range of 900–1,150℃ and at strain rates range of 0.01–10 s−1. The constitutive equation and processing maps were established to describe this complex hot deformation process. The true stress–strain curves showed that the softening effects of dynamic recovery and dynamic recrystallization are stronger than the effect of work hardening with further increasing the temperature and strain. The optimal hot working parameters of 9Cr3W3Co-ODS steel are suggested to be T = 1,050–1,100°C and ε ̇ \dot{\varepsilon } = 0.03–0.3 s−1.

Inspired by recent measurement of possible fully charmed tetraquarks in LHCb Collaboration, we investigate the mass spectra of fully heavy tetraquarks $QQ \bar Q \bar Q$ in an extended relativized quark model. Our estimations indicate that the broad structure around 6.4 GeV should contain one or more ground $cc \bar c \bar c$ tetraquark states, while the narrow structure near 6.9 GeV can be categorized as the first radial excitation of $cc \bar c \bar c$ system. Moreover, with the wave functions of the tetraquarks and mesons, the strong decays of tetraquarks into heavy quarkonium pair are qualitatively discussed, which can be further checked by the LHCb and CMS Collaborations., Comment: 7 pages, 3 figures, comments and suggestions are welcome

Self-irradiation effect induced by Pu α decay is an important influencing factor for long-term storage of Pu-based materials. In order to reveal the collision displacement cascade for uranium recoil nucleus induced by alpha decay in delta-phase plutonium at atomic level, we review the recent progress in self-irradiation of metallic plutonium and its alloys. We perform a molecular dynamics (MD) calculation on basis of modified embedded atom (MEAM) interatomic potentials, and obtain the minimum of displacement threshold energy (MDTE) for {1 1 1} lattice direction and microscopic evolution of He self-interstitial cluster. These findings are in agreement with previous experimental and theoretical results, and can be viewed as an essential input parameter for mesoscopic simulation to obtain the evolution of microscopic configuration at longer time and space, and might be also helpful for understanding the nucleation and growth mechanisms for vacancy and/or self-interstitial and its clusters, He-vacancy cluster and He bubbles in delta-phase plutonium and its alloys.

Atomically precise metal nanoclusters (NCs)-based photocatalytic systems have garnered enormous attention owing to the fascinating merits including unique physicochemical properties, quantum confin...

Directional and high-efficiency charge transport to the target active sites of photocatalyst is central to boost the solar energy conversion but is retarded by the sluggish charge transfer kinetics and deficiency of active sites. Here, we report the elaborate design of cascade unidirectional charge transfer channel over spatially multilayered CdS@CdTe@MoS2 dual core-shell ternary heterostructures by partial transformation of CdS to CdTe interim layer followed by seamless encapsulation with an ultrathin MoS2 layer. The suitable energy-level alignment and unique coaxial multilayered assembly mode among the building blocks accelerate the interfacial charge separation and transport, endowing the CdS@CdTe@MoS2 heterostructures with conspicuously enhanced visible-light-driven photocatalytic hydrogen generation performances along with good photostability. The integrated roles of ultrathin CdTe intermediate layer in passivating the defect sites of CdS NWs framework, mediating the unidirectional charge transfer cascade and prolonging the charge lifetime, were ascertained. Besides, the crucial role of the outermost MoS2 layer as the metal-free cocatalyst in enriching the surface active sites for hydrogen evolution was also determined. Our work would provide new alternatives for finely tuning the charge flow toward promising solar-to-hydrogen conversion efficiency.

Finely tuning the charge transfer constitutes a central challenge in photocatalysis, yet exquisite control of the directional charge transfer to the target reactive sites is hindered by the rapid charge recombination. Herein, dual separated charge transport channels were fabricated in a one-dimensional transition-metal chalcogenide (TMC)-based system via an elaborate layer-by-layer (LbL) self-assembly approach, for which oppositely charged metal-ion-coordinated branched polyethylenimine (BPEI) and MoS2 quantum dots (QDs) were alternately integrated to fabricate the multilayered TMC@(BPEI/MoS2 QDs)n heterostructures with controllable interfaces. Photocatalytic hydrogen generation performances of such ternary heterostructures under visible light irradiation were evaluated, which unravels that the BPEI layer not only behaves as "molecule glue" to enable the electrostatic LbL assembly with MoS2 QDs in an alternate stacking fashion on the TMC frameworks but also acts as a unidirectional hole-transfer channel. More significantly, transition-metal ions (Fe2+, Co2+, Ni2+, Cu2+, and Zn2+) coordinated on the outmost BPEI layer are able to function as interfacial electron transfer mediators for accelerating the interfacial cascade electron transport efficiency. These simultaneously constructed dual high-speed electron and hole-transfer channels are beneficial for boosting the charge separation and enhancing the photocatalytic hydrogen evolution performances.

Unidirectional and smooth charge transfer to the reactive sites plays an imperative role in boosting the solar-to-hydrogen conversion efficiency of photoelectrochemical (PEC) cells but suffers from sluggish charge transfer kinetics. Herein, as a proof-of-concept demonstration, high-speed spatially separated electron and hole transfer channels were simultaneously constructed in an integrated multilayered heterostructured photoanode via an efficient electrostatic layer-by-layer (LbL) assembly strategy, wherein a tailor-made positively charged polymer of branched polyethylenimine (BPEI) and negatively charged MoS2 quantum dot (QD) building blocks were intimately and alternately integrated on the hierarchically ordered TiO2 nanotube array (TNTA) framework in a unique “face-to-face” stacking fashion. The periodically alternately stacked ultra-thin BPEI layer in the ternary multilayered photoanode serves as a directional hole transport channel and the MoS2 QD layer functions as a cascade electron transfer channel, which synergistically contribute to the considerably enhanced separation and prolonged lifetime of charge carriers, endowing the multilayered TNTAs/(BPEI–MoS2 QDs)n photoanodes with markedly enhanced PEC water dissociation performances with respect to the single and binary counterparts under simulated solar light irradiation. Moreover, the essential role of the assembly unit was clarified. Our work would afford a new frontier to intelligently mediate the photoinduced charge flow by rationally constructing the unidirectional charge transport channels in semiconductor-based photoelectrodes for solar energy conversion.

Metal–semiconductor heterostructures have been arousing enduring interest on account of the pivotal roles of metal nanocrystals (NCs) as interfacial Schottky junction-induced charge flow mediators ...

An electrochemical sensor was successfully fabricated by coupled ammoniated modification with PBS activation on glassy carbon electrodes (CA-GCE) and characterized by electrochemical impedance spectra. The CA-GCE showed outstanding electrochemical performance, and was applied to simultaneous detection of resorcinol (RC), catechol (CC) and hydroquinone (HQ), which could be ascribed to new active sites by the introduction of amino and oxygen-containing groups and H-bonds formed between hydroxyl groups of RC, CC, and HQ with amine, hydroxyl and carboxyl groups of CA-GCE. The reaction kinetics of RC, CC, and HQ and their reaction on CA-GCE were studied. Experimental results showed that the electrochemical reaction was adsorption controlled. Under the optimal conditions, the linear detection ranges for RC, CC, and HQ were 5–200 μM, 10–300 μM, and 1–300 μM, respectively, with their detection limits of 0.47, 0.23 and 0.46 μM, respectively. Interference and repeatability was further investigated. This strategy opened a new horizon for qualitative and quantitative detection of dihydroxy benzene.

La3+- or Yb3+-doped TiO2 supported on the surface of reduced graphene oxide were fabricated by adsorbed-layer nanoreactor synthesis (ANS) coupling with a solvothermal treatment to extend photocatalysis application in the advanced treatment of simulated wastewater with high salt concentration. Results showed that La3+ or Yb3+ could distribute in the TiO2 lattice, only in ANS preparation with graphene oxide as the carrier, to replace Ti4+ during the solvothermal treatment, thus introducing TiO2 mixed-crystal and heterojunction structures in the catalysts. La3+ or Yb3+ caused lattice distortion structures and anionic vacancies in the TiO2 lattice. The anionic vacancies (oxygen vacancies) might generate Ti3+ in catalysts, thus enhancing visible-light response, due to impurity levels introduced by La3+ or Yb3+. As the strong adsorption capability of the catalyst for phenol was not interfered by salt ions in the simulated wastewater, the catalysts could efficiently degrade phenol. The highest removal rate of phenol was approximately 90%.

Water on solid surfaces is essential for a wide range of scientific and technological processes. Previous studies reveal that water molecules on metal surfaces usually form layered structures with ...

We report herein the synthesis of CuSCF3 complex supported by 6,6′-dimethyl-2,2′-bipyridine via the strategy of triphenylphosphine-mediated deoxygenation of CF3SO2Na in the presence of cuprous chloride. The molecular structure of this new cuprous complex was characterized by elemental analysis, 1H (13C, 19F) NMR spectra and verified by X-ray crystallography. Unlike the classical [(2,2′- bipyridine)Cu(SCF3)] complex, 6,6′-dimethyl-2,2′-bipyridine supported cuprous trifluoromethylthiolate complex was dimerized in the form of [{(6,6′-dimethyl-2,2′-bipyridine)Cu(SCF3)}2]. The X-ray crystal structure revealed the Cu2S2 cyclic pattern and sulfur atoms serving as the bridge. The Cu-Cu distance was equal to 3.083 Å which was remarkably longer than the analogous [{(1,10-phenanthroline)Cu(SCF3)}2] (2.5781(9) Å). This interesting phenomenon demonstrated that the substituents on the ligand scaffolds have profound influence on the coordination modes of these N,N-ligand coordinated CuSCF3 complexes.

We report herein the synthesis of CuSCF3 complex supported by 1,1'-bis(diphenyphosphino)ferrocene via deoxygenative reduction of Langlois reagent (CF3SO2Na). This cuprous complex [(dppf)Cu(SCF3)] was fully characterized by elemental analysis and 1H (13C, 19F, 31P) NMR spectra. In addition, the molecular structure of [(dppf)Cu(SCF3)] was established by X-ray crystallography. The crystal of compound 1 crystallizes in monoclinic, space group P21/n with a = 11.4366(9), b = 19.1340(16), c = 14.0625(11) Å, V = 3072.62(2) Å3, Z = 4, Z’ = 0, C35H28CuF3FeP2S, Mr = 719.00 and R-factor = 3.69. The short contacts between the two fluorine atoms of CF3S moiety and aromatic hydrogen of Cp/(Ph) rings were observed with leaving the sterically-congested fluorine untouched which highly resembled to the sibling [(PPh3)2CuSCF3]. These interesting secondary interactions in the crystal lattice were explained by the electrostatic forces in terms of the strong dipole of C-F bonds.

Sphingolipids act as structural components of cellular membranes and as signals in a variety of plant developmental processes and defense responses, including programmed cell death. Recent studies have uncovered an interplay between abiotic or biotic stress and programmed cell death. In a previous study, we characterized an Arabidopsis (Arabidopsis thaliana) cell-death mutant, accelerated cell death5 (acd5), which accumulates ceramides and exhibits spontaneous cell death late in development. In this work, we report that salt (NaCl) treatment inhibits cell death in the acd5 mutant and prevents the accumulation of sphingolipids. Exogenous application of abscisic acid (ABA) and the salicylic acid (SA) analog benzothiadiazole demonstrated that the effect of NaCl was partly dependent on the antagonistic interaction between endogenous SA and ABA. However, the use of mutants deficient in the ABA pathway suggested that the intact ABA pathway may not be required for this effect. Furthermore, pretreatment with salt enhanced the resistance response to biotic stress, and this enhanced resistance did not involve the pathogen-associated molecular pattern-triggered immune response. Taken together, our findings indicate that salt inhibits sphingolipid accumulation and cell death in acd5 mutants partly via a mechanism that depends on SA and ABA antagonistic interaction, and enhances disease resistance independent of pattern-triggered immune responses.

Semiconductor quantum dots (QDs) have garnered tremendous attention by virtue of their substantial light-harvesting and conversion efficiencies, large number of active sites, unique quantum size co...

Metal/semiconductor heterostructures have been arousing persistent interest on account of prominent roles of metal nanocrystals (NCs) in modulating charge transfer in photocatalysis. It has been ge...

In this work, the strong decay behaviors of the $\lambda-$mode low-lying $\Xi_{b}$ and $\Xi_{b}^\prime$ baryons are investigated within the $^3P_0$ model. Our results suggest that all of the low-lying $\bar 3_F$ states $\Xi_b(2S)$, $\Xi_b(1P)$, and $\Xi_b(1D)$ have small decay widths of less than 20 MeV, and these states have good potentials to be observed in the $\Xi_b^\prime \pi$ and $\Xi_b^{\prime *} \pi$ invariant masses. Further, most of the $6_F$ multiplets are relatively narrow and may decay into the $\Xi_b \pi$, $\Xi_b^\prime \pi$, $\Xi_b^{\prime *} \pi$, and $\Lambda_b \bar K$ final states. Considering the masses and strong decay behaviors, we can assign the newly observed $\Xi_{b}(6100)$ resonance as the $\Xi_b(1P)$ state with $J^P=3/2^-$ and interpret the $\Xi_{b}(6227)$ structure as the $J^P=3/2^-$ $\Xi_b^\prime(1P)$ state with a proper mixing angle. We expect that our predictions for these excited bottom strange baryons will provide helpful information for future experimental research., Comment: 7 pages, 3 figures. Minor modifications, accepted version

In this work, we investigate the decays of the fully open-flavor tetraquark state ${X}_{0}(2900)$ which was observed by the LHCb collaboration very recently. By using an effective Lagrangian approach, the partial widths of ${X}_{0}(2900)$ are estimated, where ${X}_{0}(2900)$ is assumed to be an $S$-wave ${\overline{D}}^{*}{K}^{*}$ hadronic molecule with $I=0$. It is found that the estimated results are in agreement with the experimental observations. Moreover, we also predict the decay behaviors of the other unobserved ${\stackrel{\texttildelow{}}{X}}_{J(J=1,2)}$, which are the spin partners of the ${X}_{0}(2900)$ in the $S$-wave ${\overline{D}}^{*}{K}^{*}$ picture. It is pointed out that the ${\stackrel{\texttildelow{}}{X}}_{1}$ state with $I=0$ is a broad state with the width more than 100 MeV, while another ${\stackrel{\texttildelow{}}{X}}_{2}$ state with $I=0$ is a narrow state with the width approaching half of that for the ${X}_{0}(2900)$. In addition, our results also show that the ${\overline{D}}^{*}K$ mode is expected to be the dominant decay mode for both ${\stackrel{\texttildelow{}}{X}}_{1}$ and ${\stackrel{\texttildelow{}}{X}}_{2}$. Searching for those unobserved ${\stackrel{\texttildelow{}}{X}}_{J(J=1,2)}$ in the future experiments might be helpful to understand the nature of ${X}_{0}(2900)$.

The high-power solid-state laser facility control system is a large-scale distributed control system, and its development and integration process is complicated. During the control system integration process, a large amount of control software needs to be developed to achieve the integration of various hardware devices and sub-systems. At the same time, the control system is generally divided into several sub-systems and developed by developers from different institutions. The modules are strongly coupled and developed. The difference in schedule will affect the integration debugging efficiency of the control system. In order to improve the delivery efficiency and software quality of the control system, this paper proposes a continuous integration strategy for the laser facility control system, and builds an integrated test platform based on the continuous integration tools and integrated control software testing tools to achieve software design, development, testing, and deployment automation has greatly improved the agility of control software development.

In present work, we systematically calculate the mass spectra of open charm and bottom tetraquarks $q q\bar q \bar Q$ within an extended relativized quark model. The four-body relativized Hamiltonians including the Coulomb potential, confining potential, spin-spin interactions, and relativistic corrections are solved by using the variational method. It is found that the predicted masses of four $0^+$ $ud\bar s \bar c$ states are 2765, 3065, 3152, and 3396 MeV, which disfavor the assignment of the newly observed $X_0(2900)$ as a compact tetraquark. Moreover, the whole mass spectra of the open charm and bottom tetraquarks show quite similar patterns, which preserve the light flavor SU(3) symmetry and heavy quark symmetry well. In addition, our results suggest that the flavor exotic states $nn\bar s \bar c$, $nn\bar s \bar b$, $ss\bar n \bar c$, and $ss\bar n \bar b$ and their antiparticles can be searched in the heavy-light meson plus kaon final states by future experiments. More theoretical and experimental efforts are needed to investigate these singly heavy tetraquarks., 11 pages, 3 figures, comments and suggestions are welcome

In the present work, the mass spectra of doubly heavy tetraquarks ${T}_{Q{Q}^{\ensuremath{'}}}$ are systematically investigated in a relativized quark model. The four-body systems including the Coulomb potential, confining potential, spin-spin interactions, and relativistic corrections are solved within the variational method. Our results suggest that the $I{J}^{P}=0{1}^{+}\text{ }\text{ }bb\overline{u}\overline{d}$ state is 54 MeV below the relevant $\overline{B}{\overline{B}}^{*}$ thresholds, which indicates that both strong and electromagnetic decays are forbidden, and thus this state can be a stable one. Its large hidden color component and small root mean square radius demonstrate that it is a compact tetraquark rather than a loosely bound molecule or pointlike diquark-antidiquark structure. Our predictions of the doubly heavy tetraquarks may provide valuable information for future experimental searches.

Recent lattice QCD calculations showed that a dNΩ similar to the deuteron with baryon number B=2 and with a small binding energy might exist. In this work we propose a hadronic molecular approach to study the dynamical properties of this exotic state. We employed a phenomenological Lagrangian approach to describe the coupling of the dNΩ to its constituents and the strong decays into conventional hadrons, dNΩ→ΛΞ and dNΩ→ΣΞ. Predictions for the sum of the decay rates are in the range of a few hundred keV. In addition, we find that the dNΩ→ΛΞ mode is dominant, preferably searched for in a future Relativistic Heavy Ion Collider (RHIC) experiment.

The ρ meson gravitational form factors are studied based on a light-front constituent quark model which has been successfully employed to calculate its generalized parton distributions and some low-energy observables. The distributions of energy, spin, pressures, and shear forces inside the ρ meson are explicitly given.

Recent years have witnessed an explosive investigation on the construction of graphene (GR)–semiconductor composite photocatalysts, but the specific correlation of the interface integration mode between GR and a semiconductor with the interfacial charge transfer characteristics is yet to be clearly clarified. To this end, a facile, green and surface linker-triggered self-assembly has been designed to construct GR-encapsulated antimony sulfide nanorod (Sb2S3 NRs–GR) ensembles, wherein tartaric acid-capped intrinsically negatively charged Sb2S3 NRs and surface-modified positively charged GR nanosheets were utilized as the building blocks. It was unveiled that the exquisitely designed interface configuration afforded by the intimate encapsulation of Sb2S3 NRs with GR via an electrostatic/hydrogen interaction is beneficial for fully harnessing the structural merits of GR in boosting light absorption, increasing the specific surface area and accelerating the interfacial electron transfer kinetics. Thus, the lifetimes of the photogenerated charge carriers were synergistically prolonged over Sb2S3, resulting in the considerably enhanced visible-light-responsive photoredox performances of the Sb2S3–GR nanocomposites toward the photoreduction of heavy metal ions and mineralization of organic pollutants compared with the blank Sb2S3 and nanocomposite counterpart without a finely tuned interface. More importantly, the crucial role of interface configuration between GR and the Sb2S3 NRs in dictating the interfacial charge transfer efficiency was substantiated. In addition, the predominant active species in the photoredox catalysis were determined and the corresponding photocatalytic mechanism was elucidated. Our work sheds light on mediating the interfacial charge transfer via rational interface configuration modulation toward substantial solar energy conversion.

Plant activators are chemicals that induce plant defense responses to various pathogens. Here, we reported a new potential plant activator, 6-(methoxymethyl)-2-[5-(trifluoromethyl)-2-pyridyl] pyrimidin-4-ol, named PPA2 (pyrimidin-type plant activator 2). Unlike the traditional commercial plant activator benzothiadiazole S-methyl ester (BTH), PPA2 was fully soluble in water, and it did not inhibit plant growth or root system development in rice (Oryza sativa). PPA2 pretreatment significantly increased plant resistance against bacterial infection in both Arabidopsis and rice, in conjunction with increases in the level of jasmonoyl-isoleucine and 12-oxo-phytodienoic acid. In addition, metabolite profiling indicated that BTH significantly reduced the abundance of various primary metabolites in rice seedlings, including most amino acids, sugars, and organic acids, by contrast, PPA2 promoted their synthesis. Our results thus indicate that PPA2 enhances plant defenses against bacterial infection through the jasmonic acid pathway, and that as a water-soluble compound that can promote the synthesis of primary metabolites it has broad potential applications in agriculture.

We report a detailed study of tunneling spectra measured on 2H-Ta_{x}Nb_{1-x}Se_{2} (x=0∼0.1) single crystals using a low-temperature scanning tunneling microscope. The prominent gaplike feature, which has not been understood for a long time, was found to be accompanied by some "in-gap" fine structures. By investigating the second-derivative spectra and their temperature and magnetic field dependencies, we were able to prove that inelastic electron tunneling is the origin of these features and obtain the Eliashberg function of 2H-Ta_{x}Nb_{1-x}Se_{2} at an atomic scale, providing a potential way to study the local Eliashberg function and the phonon spectra of the related transition-metal dichalcogenides.

Dipyridyl benzene skeleton (Py-ph-Py) was synthesized and chem.-grafted on titanium dioxide through hydrothermal method. The novel organic/inorganic hybrid structure DPA-TiO2 displays remarkable photocatalytic activity and stability. The structural and surface characterization revealed that hybrid composites were linked with chemical ester bonds, which enabled the organic skeletons on the surface to act as charming transmitters of charges. The hybrid structure not only shortens the bond gap of catalyst hence to make charges be generated under visible light, but also transfers the photogenerated electrons in time to avoid them recombining with positive holes. In addition, the excellent adsorption capacity to waste organic compounds also contributes to its wonderful catalytic properties. The novel methodology is of great instructive to the utilization of solar energy to dispose environmental pollutions.

The Cauchy problem for the 3D incompressible magneto-hydrodynamics equations in critcal spaces is considered. We first prove the global well-posedness of mild solution for the system in some time dependent spaces. Furthermore, we obtain analyticity of the solution.

Vanadium oxide is a type of material with high temperature coefficient of resistance (TCR) for bolometric infrared detection. In this letter, the effects of growth conditions of B-phase crystalline VO2, including reaction temperature, reaction time and quantities of precursors, were systematically investigated. Free-standing VO2(B) thin film composed of nano-sheets stacking on the (0 0 1) plane was prepared. The in-plane and out-of-plane TCRs were measured. A superior in-plane TCR of −3.0%/K was observed at room temperature, while the out-of-plane TCR only was −1.7%/K. We further showed that the I-V behavior of VO2(B) was voltage-dependent, and its possible origin was discussed.

The recent studies of the newly observed dibaryon resonance d*(2380) in a constituent chiral quark model are briefly summarized. An overall analysis of the obtained pionic decay widths, comparing with the experimental data, shows that a compact hexaquark system might be a reasonable interpretation for this dibaryon resonance with I(JP ) = 0(3+).

The oriental fruit fly, Bactrocera dorsalis (Hendel), is a major polyphagous insect pest with a worldwide distribution. The effects of temperature on stage-specific development in B. dorsalis were investigated at eight constant temperatures (13.0 °C, 14.4 °C, 16.2 °C, 19.5 °C, 23.8 °C, 27.7 °C, 31.8 °C and 34.8 °C). B. dorsalis developed successfully from the egg stage to the adult stage at all the tested temperatures, except at the lowest temperatures (13.0 °C and 14.4 °C). Stage-specific lower developmental thresholds and thermal constants were determined using linear regression. The lower and higher temperature threshold (TL and TH, respectively) were estimated using the Sharpe-Schoolfield-Ikemoto model. The lower developmental threshold and thermal constant from egg to adult emergence were 9.8 °C and 325.5 degree-days, respectively. The intrinsic optimum temperatures of the egg, larval, pupal and egg to pupal stage were 20.7 °C, 21.8 °C, 21.1 °C, and 22.4 °C, respectively. The temperature range of the B. dorsalis total immature stage from TL to TH was 20.4 °C (13.8 °C - 34.2 °C). The stage-specific developmental completion of B. dorsalis was determined using a two-parameter Weibull function. The daily adult emergence frequency of B. dorsalis was estimated in relation to adult age and temperature using non-linear developmental rate functions and the Weibull function. The date of cumulative 50% adult emergence estimated using non-linear functions was approximately one day earlier than the experimentally observed date. Thermal performance was compared among B. dorsalis populations from different locations.

Phthalate plasticizers residue in food is a serious threat to public health. Spores of Ganoderma lucidum are easy to be contaminated with phthalates during collection and processing. In this study, supercritical fluid extraction (SFE) was performed to remove phthalates in spores of G. lucidum, and the effects on acid and peroxide values of spores’ oil were also evaluated. The results showed SFE removed 100% of the residual di-iso-butyl phthalate, di-n-butyl phthalate and di-2-ethylhexyl phthalate in the spores of G. lucidum. No significant differences in polysaccharides content and fatty acid composition were observed between SFE and control spores. However, the triterpenoid extracts of SFE spores had a 7.45% increase, significantly higher than that in control spores. Accelerated oxidation tests further implied that SFE could improve the stability of spores’ oil. Our results suggested SFE is a potential approach to remove phthalate from food related products. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s10068-018-0404-3) contains supplementary material, which is available to authorized users.

We report the highly ordered array of CoPc-vacancies and the single-molecule rotors inside the vacancies. When CoPc molecules are deposited on Cd(0001) at low-temperature, three types of molecular vacancies appeared randomly in the CoPc monolayer. Annealing the sample to higher temperature leads to the spontaneous phase separation and self-organized arrangement of the vacancies. Highly ordered arrays of two-molecule vacancies and single-molecule vacancies have been obtained. In particular, there is a rotating CoPc molecule inside each single-molecule vacancy, which constitutes the array of single-molecule rotors. These results provide a new routine to fabricate the nano-machines on a large scale.

Streptochlorin, a small indole alkaloid isolated from marine Streptomyces sp., exhibits a wide range of potent biological activities. An efficient and economic synthetic protocol for streptochlorin has been developed and validated, 4 steps from indole in a total yield of 45%, and further applied for the synthesis of its analogues. Biological testing showed that most of the target compounds exhibited potential antifungal activity in the primary assays, especially compounds 6, 7 and 9c were the most active ones, representing effective activity against the phytopathogenic fungi screened in preliminary test and might be explored for the study of mode of action in the future.

Poly(3-hexylthiophene) (P3HT), being a prototypic conjugated polymer, bears a high charge mobility that is sensitive to its packing configuration in the condensed phase. Despite its extensive experimental study with X-ray diffraction, its specified packing structure still remains stymied. This study searched for possible structures of crystalline P3HT and identified the one that holds a simulated Raman spectrum most approximate to the experimental one of ordered P3HT aggregates in the frozen solvent. The spectral correspondence shows that the Raman-active C–C stretch peak exhibits a red shift in frequency, while the C═C stretch peak displays a blue shift as the layer planarity of P3HT is relaxed. Moreover, the C═C peak splits into two when adjacent thiophene rings in the P3HT chain hold a dihedral angle of 22° with respect to each other. This study demonstrates that Raman spectroscopy plus first-principles simulations can serve as a powerful tool to resolve fine structures of molecular crystals.

The adsorption of water molecules on the Cd(0001) surface has been systematically investigated in the absence or presence of the electric field using first principles calculations based on density functional theory. It has been determined that the adsorption is enhanced by the electric field. From the geometries and energetics, we find that the water-cadmium interaction become stronger (weaker) under a negative (positive) field in the adsorbed monomer. Otherwise, the formation of the hydrogen bonds makes it difficult for molecules in the water clusters to response the electric field. Most importantly, the stability of the water bilayers depends on the strength of the negative electric field. Instead of the H-up bilayer, the H-down bilayer is more stable when the negative field is sufficiently strong. In this case, the dipole-field interaction is the dominant interaction in the change of stability. These results are helpful in the understanding of the fundamental processes at the water-electrode interfaces.

The life table data for the oriental fruit fly, Bactrocera dorsalis (Hendel), at different adult sex ratios (1 female: 1 female, 1 female: 50 male, 50 female: 1 female free-choice mating, and 50 female: 1 male no-choice mating) were collected to determine the effects of sex-ratio manipulation on current pest control procedures. At 1 female: 1 male, females mated, on average, 2.3 times during their lifetime with a mean fecundity (F) of 1,122 eggs. The net reproductive rate (R-0), intrinsic rate of increase (r), finite rate (lambda), and mean generation time (T) were 561.0 offspring, 0.1693 d(-1), 1.1844 d(-1), and 37.4 d, respectively. At 50 female: 1 male free-choice mating, males mated 46.7 times during their lifetime, while at 50 female: 1 male no-choice mating, males mated on average 50 times during their lifetime, and all females mating only once in both treatments. The values for F, r, and lambda were significantly lower for both 50 female: 1 male treatments than those in the 1 female: 1 male group; the R-0 values, however, were either equal to or even higher than those in the 1?: 1? treatment. In the male-biased sex ratio (1 female: 50 male), fecundity was the highest (1,610 eggs) and female average life span the longest (166 d), while the R-0 was the lowest (31.6 offspring) among all treatments. Population projections showed that even at a sex ratio of 50 female: 1 male, B. dorsalis could still produce a large number of offspring. These findings demonstrate that management strategies for controlling B. dorsalis could be properly evaluated by using demographic methods. Because female annihilation appears to be a more effective control strategy, it should be considered as a viable alternative.

Biofouling, as one of the membrane foulings, is the major obstacle limiting the application of polyamide (PA) thin-film composite (TFC) nanofiltration (NF) membranes in reclamation of wastewaters and treatment of industrial fluids. Herein, we introduced a facile and effective strategy for the modification of traditional PA-TFC NF membranes to improve water permeability and biofouling resistance. Specifically, three reactive guanidine molecules were successfully bonded onto the surface of PA-TFC membranes using chemical reactions between the amine groups of guanidine and the residual acyl chloride groups on the nascent PA-TFC membrane. The covalent attachment of guanidines can significantly enhance water permeability without compromising salt rejection. For instance, for 2 g L−1 Na2SO4 aqueous solution, the water flux of NFM2 increased from 25.2 L m−2 h−1 to 68.4 L m−2 h−1 at 25 °C and 0.6 MPa compared to the traditional piperazine (PIP)–trimesoyl chloride (TMC) membrane, while around 98.3%. Na2SO4 rejection was maintained. Moreover, the membranes were endowed with easy-cleaning properties, which can remarkably prevent foulant adhesion, with the water flux recovery ratio being as high as 98.9%. The developed TFC membranes also showed excellent anti-adhesive and antimicrobial activities against Gram-negative Escherichia coli K12 (E. coli), Gram-positive Bacillus pumilus LDS33 (B. pumilus) and Aspergillus parasiticus JFS (A. parasiticus). Therefore, the resultant guanidinium-functionalized NF membranes which have integrated high permselectivity and superior fouling resistance properties are promising materials for fabricating a new generation of anti-fouling/antimicrobial surfaces that are applicable to many applications such as water desalination and softening and wastewater treatment.

Si has been extensively examined as a potential alternative to carbonaceous negative materials, because it shows exceptional gravimetric capacity and abundance. In recent years, the strategy of using nano-structured silicon materials as building blocks to build micro-sized silicon-based materials has been widely studied. In this work, a commercialized and benchmark micro-sized silicon-based material (denoted as SiOx/C) is used as research target and three groups of materials with different particle size distributions (PSDs) were obtained by simply mechanical sieving. The effects of PSD on the electrochemical performance and electrode structure of micro-sized silicon-based negative electrodes are discussed. The optimized selection of micro-sized active material PSD presents a comprehensive way for developing and characterizing Si-based negative electrodes for practicable high-energy LIBs. In this case, the optimized SiOx/C composite electrode with a particle size of 22.7 μm and narrow PSD shows enhanced cycling stability with a high capacity retention of 84.31% over 100 cycles.

Tunable and efficacious modulation of photo-induced charge carrier separation and transfer in photoelectrochemical (PEC) cell for solar water splitting constitute a central challenge. Herein, high-efficiency plasmon-induced hot carriers transfer channel has been rationally and progressively constructed by judicious layer-by-layer assembly of graphene quantum dots (GQDs) and plasmonic metal nanocrystals (Ag NCs) on the one-dimensional semiconductor (TiO2 nanorods arrays, TiO2 NRs) framework, resulting in a well-defined spatially multilayered photoanode. The unique and alternate integration of GQDs with Ag NCs on the TiO2 NRs is closely associated with charge transfer behaviors. It was unveiled that Ag NCs in situ integrated in the multilayered film enable hot electron generation, and simultaneously play a crucial role in finely relaying electron transfer from GQDs to TiO2. This gives rise to significantly enhanced solar-powered PEC water splitting performances of TiO2 NRs@Ag@GQDs ternary multilayered heterostructure, which far surpasses the corresponding binary and single counterparts. Consequently, intrinsic correlation of metal NCs with GQDs in terms of charge transport was for the first time clarified.

An easily available novel fluorescent probe has been synthesized by reacting rhodamine hydrazide and 2-(thiophen-2-yl)acetyl chloride. Upon mixed with Fe 3+ in aqueous solution, the dramatic enhancement of fluorescence intensity as well as the color change of the solution were observed. Significantly, the probe displayed highly selective and sensitive recognition ability toward Fe 3+ with a limit of detection (LOD) down to 10 −7 M. The Job’s plot indicated the formation of 1:1 complex between the probe and Fe 3+ , and the complexation stability constant can be calculated as 2.95 × 10 4 M −1 . The presence of common coexisting alkali, alkaline earth, and transition metal ions showed small or no interference to the detection of Fe 3+ . All these unique features make it particularly favorable for cellular Fe 3+ imaging applications. The confocal fluorescent images demonstrated that the probe was cell-permeable and could be used for highly sensitive monitoring of Fe 3+ levels in living cells with satisfying resolution.

Although metal–organic frameworks (MOFs) have promising applications in various fields, efforts to utilize MOFs as emissive layers in electroluminescent devices have not progressed well due to their intrinsic nature. Fortunately, by using fluorene derivatives and cuprous ions, a novel MOF (Cu-P6) has been synthesized for blue electrophosphorescence. The topological structure of Cu-P6 displays a 3-connected uninodal net with a cross-stacking pattern. Such a structure allowed phosphorescent Cu-P6 to exhibit a good heat resistance and luminous efficiency (Φ = 0.62) at crystalline state. By containing both donor and acceptor in the structure, Cu-P6 possesses a balanced electron and hole mobility. Especially, electrical-driven deep-blue emission of a MOF was reported for the first time. Overall, this work may open new perspectives on developing highly efficient electrophosphorescent devices based on MOFs. The utilization of earth-abundant cuprous ions is another attractive feature of Cu-P6.

Structural evolution of Ga thin films grown on the Si(111)- 3 × 3 -Ga template have been investigated with a low-temperature scanning tunneling microscopy (STM). The first Ga layer exhibits a stripe structure along the base vectors of Si(111) lattices. Individual Ga dimers have been directly visualized from the high-resolution STM images of the first Ga layer. The second Ga layer reveals a pseudo 1×1 structure with respect to the Si(111). A new 5×5 phase has been found in the second Ga layer when annealing the sample to 120 ℃. Further annealing to 150 ℃ leads to the formation of 6.3×6.3 phase, which is more stable than the 5×5 phase. The existences of a variety of superstructures of Ga films demonstrates the delicate balance between the interactions of Si(111)-Ga and Ga-Ga. These results shed important light on the epitaxial growth mechanism of Ga films on semiconductor surfaces.

A novel visible light excitable chemosensor based on a rhodamine 6G naphthylurea conjugate was successfully synthesized, which shows highly selective and sensitive recognition ability toward H2PO4− in H2O-CH3CN (1/1, v/v). In response to H2PO4−, the probe provided remarkable fluorescence intensity change and clear color change from colorless to pink and the background anions showed small or no interference. The confocal fluorescent images demonstrated that the probe was cell-permeable and could effectively detect intracellular dihydrophosphate in living cells.

The gas-phase reaction of activation H H bond of H2 by FeO2+(6A1/4B2) has been investigated using DFT at the CCSD(T)//B3LYP/6-311G(2d, p) level. The calculation results show that the reaction is a TSR and belongs to the fourth case of the Hammond postulate. The involved crossing between the potential energy surfaces is discussed and the CPs and MECPs are located. In addition, the orbital interaction for ion-molecule complexes 4IM1 and 6IM1 have been examined by FMO analysis. Finally, the frontier molecular orbital interaction analysis about 4TS1 and 6TS1 were used to gain useful information about the H H σ bond activation by FeO2+.