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In this paper, we study the existence of at least two nontrivial solutions for a class of double-phase problems with a small perturbation. We provide one new criterion to ensure the existence of tw...

The aim of this paper is to establish the existence of solutions for singular double-phase problems depending on one parameter. This work improves and complements the existing ones in the literature. There seems to be no results on the existence of solutions for singular double-phase problems.

In this paper, we consider a nonlocal p(x)-Kirchhoff problem with a p+-superlinear subcritical Caratheodory reaction term, which does not satisfy the Ambrosetti&ndash, Rabinowitz condition. Under some certain assumptions, we prove the existence of nontrivial solutions and many solutions. Our results are an improvement and generalization of the corresponding results obtained by Hamdani et al. (2020).

We calculate the rate per unit volume of hydrogen-poor superluminous supernovae (SLSNe-I) based on the 17 events discovered with the Pan-STARRS1 Medium Deep Survey (PS1 MDS). Two forms of the luminosity function (LF) are assumed : a log-normal form and a single power-law form, respectively. The rate of SLSNe-I is assumed to be proportional to the cosmic star formation rate with an additional redshift evolution of ( 1 + z ) α . Our results show that the single power-low form fits the data better than the log-normal form, and the event rate of SLSNe-I is proportional to the cosmic star formation rate directly (with α = 0 ). We measure the SLSNe-I rate to be about 40 yr − 1 Gpc − 3 at a weighted mean redshift of z ¯ = 0.89 , which is consistent with previous works.

Glomalin-related soil proteins (GRSP), which has been used as a presumable biological indicator of soil quality, is of vital ecological importance. In this research, we tested the GRSP content and physicochemical property of soils collected in mountain, urban and suburb areas of Beijing City. Besides, the fluorescence property of GRSP was also studied by using EEM-PARAFAC. The results showed that GRSP could be decomposed into five compounds, terrestrial humic-like substances UVA, terrestrial humic-like substances UVC, oxidized quinones, soil fulvic acid and amino acids. The GRSP content and protein-like fluorescence substances in urban and suburb areas significant decreased and oxidized quinones content elevated in comparison with those in mountain area. The physicochemical property was also shaped by urbanization. Compare to mountain area, moisture content, total organic matters and total nitrogen significantly decreased in urban area soil and suburb area. GRSP content, terrestrial humic-like substances UVA and oxidized quinones content showed significant correlation with soil organic matter and total nitrogen. Base on that, an integrated index system mainly consisting of GRSP concentration and C1 component and C3 component was recommended to evaluate the soil health status.

The cusp burst radiation of superconducting cosmic string (SCS) loops is thought to be a possible origin of observed fast radio bursts with the model-predicted radiation spectrum and the redshift- and energy-dependent event rate, we fit the observational redshift and energy distributions of 21 Parkes fast radio bursts and constrain the model parameters. It is found that the model can basically be consistent with the observations, if the current on the SCS loops has a present value of $\ensuremath{\sim}{10}^{16}{\ensuremath{\mu}}_{17}^{9/10}\text{ }\text{ }\mathrm{esu}\text{ }{\mathrm{s}}^{\ensuremath{-}1}$ and evolves with redshift as an empirical power law $\ensuremath{\sim}(1+z{)}^{\ensuremath{-}1.3}$, where ${\ensuremath{\mu}}_{17}=\ensuremath{\mu}/{10}^{17}\text{ }\text{ }\mathrm{g}\text{ }{\mathrm{cm}}^{\ensuremath{-}1}$ is the string tension. This current evolution may provide a clue to probe the evolution of the cosmic magnetic fields and the gathering of the SCS loops to galaxy clusters.

Fast radio bursts (FRBs) are usually suggested to be associated with mergers of compact binaries consisting of white dwarfs (WDs), neutron stars (NSs), or black holes (BHs). We test these models by fitting the observational distributions in both redshift and isotropic energy of 22 Parkes FRBs, where, as usual, the rates of compact binary mergers (CBMs) are connected with cosmic star formation rates by a power-law distributed time delay. It is found that the observational distributions can well be produced by the CBM model with a characteristic delay time from several ten to several hundred Myr and an energy function index $1.2\lesssim\gamma\lesssim1.7$, where a tentative fixed spectral index $\beta=0.8$ is adopted for all FRBs. Correspondingly, the local event rate of FRBs is constrained to $(3-6)\times10^4f_{\rm b}^{-1}(\mathcal T/270\rm s)^{-1}(\mathcal A/2\pi)^{-1}\rm ~Gpc^{-3}yr^{-1}$ for an adopted minimum FRB energy of $E_{\min}=3\times10^{39}$ erg, where $f_{\rm b}$ is the beaming factor of the radiation, $\mathcal T$ is the duration of each pointing observation, and $\mathcal A $ is the sky area of the survey. This event rate, about an order of magnitude higher than the rates of NS-NS/NS-BH mergers, indicates that the most promising origin of FRBs in the CBM scenario could be mergers of WD-WD binaries. Here a massive WD could be produced since no FRB was found to be associated with a type Ia supernova. Alternatively, if actually all FRBs can repeat on a timescale much longer than the period of current observations, then they could also originate from a young active NS that forms from relatively rare NS-NS mergers and accretion-induced collapses of WD-WD binaries., Comment: 7 pages, 4 figures

By employing a simple semi-analytical star formation model where the formation rates of Population (Pop) I/II and III stars can be calculated, respectively, we account for the number distribution of gamma-ray bursts (GRBs) with high pseudo-redshifts that was derived from an empirical luminosity-indictor relationship. It is suggested that a considerable number of Pop III GRBs could exist in the present sample of Swift GRBs. By further combining the implication for the star formation history from the optical depth of the CMB photons, it is also suggested that only a very small fraction 0.6% of Pop III GRBs could have triggered the Swift BAT. These results could provide an useful basis for estimating future detectability of Pop III stars and their produced transient phenomena., 5 pages, 3 figures, 1 table, accepted for publication in New Astronomy

The author used CFD software to simulate when group panel-type radiator quantity, space, height of gooseneck have changed, how temperature distribute on the radiator. To obtain when group panel-type radiator quantity, space, height of gooseneck and other factors have changed, the laws of heat transfer efficiency changed and analyzed the reasons for emergence of such laws in theory. The optimal group of panel-type radiator improvement program is explored, to provide guidance for the practical application of engineering.

The similarity of the host galaxy of FRB 121102 with those of long gamma-ray bursts and Type I super-luminous supernovae suggests that this FRB could be associated with a young magnetar. By assuming the FRB emission to be produced within the magnetosphere, we derive a lower limit on the age of the magnetar, after which GHz emission is able to escape freely from the dense relativistic wind of the magnetar. Another lower limit is obtained by requiring the dispersion measure contributed by the electron/positron pair wind to be consistent with the observations of the host galaxy. Furthermore, we also derive some upper limits on the magnetar age with discussions on possible energy sources of the FRB emission and the recently-discovered persistent radio counterpart. As a result, some constraints on model parameters are addressed by reconciling the lower limits with the possible upper limits that are derived with an assumption of rotational energy source., 5 pages, 1 figure, revised according to the referee's comments. Accepted for publication in ApJL

A chassis dynamometer study was conducted to compare the characteristics of particle emissions from a port fuel injection (PFI) and a gasoline direct injection (GDI) car, both of which comply with Euro 4 exhaust emission standards. Experiments were carried out over the New European Driving Cycle (NEDC), the ECE–15 segments, the period from 0 to 49 s within the NEDC procedure (FSE) and the Extra Urban Driving Cycle segment. Exhaust particles were characterized in terms of the particle number, surface area, volume and size distributions between 30 nm and 1 μm. Under the NEDC, the GDI car had particle emissions weighted by particle number, surface area and volume that were 56–2 739% higher than the emissions from the PFI car in the range of particle size measured, and the particle number, volume and surface area emissions per km for the GDI car are respectively 5.3, 9.0 and 14.6 times higher than those for the PFI car. Among the testing conditions employed, the highest concentrations of average particle number, surface area and volume were found in the FSE, and the particle number, surface area and volume for the GDI car were respectively 9.5, 33.2 and 39.8 times higher than those for the PFI car. Moreover, the peak of the particle size distributions for the PFI car was toward a smaller size, while that for the GDI was toward a larger size, indicating that particles emitted by the PFI car are much smaller than those emitted by the GDI car.

An experimental study was carried out on the direct nitration of 1,4,5,8-tetraaza-bicyclo-[4,4,0]-decane to synthesize 1,4,5,8-tetranitro-1,4,5,8-tetraazabicyclo-[4,4,0]-decane (TNAD) with N2O5 catalyzed by acidic ionic liquids. Various ionic liquids, such as [HMim]X, [(CH2)4SO3HMim]X and [Capl]X (X− = pTSO−, NO3−, HSO4−), and various parameters such as equivalents of ionic liquid, molar ratio of N2O5 to the starting material, reaction time and temperature, and solvent were investigated. Ionic liquid [(CH2)4SO3HMim]HSO4 showed better catalytic activity. In the presence of 3% molar ratio of [(CH2)4SO3HMim]HSO4 ionic liquid to the staring material, the yield of 1,4,5,8-tetranitro-1,4,5,8-tetraazabicyclo-[4,4,0]-decane was improved by 6.2% compared to the system without ionic liquid.

The fuel flow characteristics in diesel nozzle orifice are key factors to the atomization of fuel near the nozzle orifice. In the paper, two-phase flow model is used to simulate the complex flow features in nozzle orifice, and to study the influences of the relative position of nozzles orifice axis and nozzle axis, and inclination angle of nozzle hole on the internal flow feature.

The efficacy of Rehmannia glutinosa which as a large quantity of traditional Chinese medicine is significant. However, the land must be given up after one season of R. glutinosa cultivation or replanted after a period of 8-10 years because of the severe continuous cropping obstacles. MicroRNAs is a class of endogenous non-coding small RNAs, which participate in regulation of physiological activities by target mRNA cleavage or translational repression in plants. In recent years,studies on the role of miRNAs in plants have made significant progresses,especially in medicinal plants．MiRNAs from some different medicinal plant species have been identified with regulatory effects．When plants are exposed to environmental stress, miRNAs act on stress-related genes and initiate stress-resistance mechanisms in the body against adverse factors. R. glutinosa is also a kind of environmental stress. It is conducive to deciphering the molecular mechanism of continuous cropping obstacles for us by researching miRNAs. This article reviews the production of miRNAs, mechanism, research approaches and characteristics of resisting the environmental stresses in plants, the development trends and future prospect of R. glutinosa miRNAs research.

The hyperluminous X-ray source (HLX-1, the peak X-ray luminosity $\sim 10^{42}\rm erg\ s^{-1}$) near the spiral galaxy ESO 243-49 is possibly the best candidate for intermediate mass black hole (IMBH), which underwent recurrent outbursts with a period of $\sim 400$ days. The physical reason for this quasi-periodic variability is still unclear. We explore the possibility of radiation-pressure instability in accretion disk by modeling the light curve of HLX-1, and find that it can roughly reproduce the duration, period and amplitude of the recurrent outbursts HLX-1 with an IMBH of ~10^5Msun. Our result provides a possible mechanism to explain the recurrent outbursts in HLX-1. We further find a universal correlation between the outburst duration and the bolometric luminosity for the BH sources with a very broad mass range (e.g., X-ray binaries, XRBs, HLX-1 and active galactic nuclei, AGNs), which is roughly consistent with the prediction of radiation-pressure instability of the accretion disk. These results imply that "heartbeat" oscillations triggered by radiation-pressure instability may appears in different-scale BH systems., ApJ in press; 15 pages, 5 Figures

Caixiashan Pb-Zn deposit is the largest Pb-Zn deposit discovered in the middle Tianshan area. Examples of Carboniferous magmatic and tectonic activity are widely distributed. The ore bodies are controlled by EW trend faults, based on field observations. The main ore minerals are galena, sphalerite, pyrrhotite, pyrite and chalcopyrite, while quartz, sericite and calcite are the main alteration minerals. The ore also exhibits minerals zoning. In addition, the wide range of S isotopic composition, high temperature and moderate salinity of fluid inclusions, and good correlation of ore and wall rock Pb isotopes together with H, O, C isotopic compositions indicate mixing of magmatic origin and upper sedimentary rocks. Combined with high concentration of pyrite and pyrrhotite and some argentite, the Pb-Zn deposit may be controlled by the Hercynian orogeny, which controlled the EW-NEE faults and Carboniferous igneous rocks. The faults provided the channel for fluid transport and the igneous rocks provided heat and main source of the metals. When the fluid passed through metal-bearing rocks, it extracted Pb, Zn, Ag etc.. Interaction of the metal-bearing fluid with the brecciated and fractured marble caused the metals to be deposited. Thus the Caixiashan Pb-Zn deposit is a fault-controlled hydrothermal deposit.

The accumulation of {\it Swift} observed gamma-ray bursts (GRBs) gradually makes it possible to directly derive a GRB luminosity function (LF) from observational luminosity distribution, where however two complexities must be involved as (i) the evolving connection between GRB rate and cosmic star formation rate and (ii) observational selection effects due to telescope thresholds and redshift measurements. With a phenomenological investigation on these two complexities, we constrain and discriminate two popular competitive LF models (i.e., broke-power-law LF and single-power-law LF with an exponential cutoff at low luminosities). As a result, we find that the broken-power-law LF could be more favored by the observation, with a break luminosity $L_b=2.5\times10^{52}\rm erg s^{-1}$ and prior- and post-break indices $\nu_1=1.72$ and $\nu_2=1.98$. For an extra evolution effect expressed by a factor $(1+z)^{\delta}$, if the matallicity of GRB progenitors is lower than $\sim0.1Z_{\odot}$ as expected by some collapsar models, then there may be no extra evolution effect other than the metallicity evolution (i.e., $\delta$ approaches to be zero). Alternatively, if we remove the theoretical metallicity requirement, then a relationship between the degenerate parameters $\delta$ and $Z_{\max}$ can be found, very roughly, $\delta\sim2.4(Z_{\max}/Z_{\odot}-0.06)$. This indicates that an extra evolution could become necessary for relatively high metallicities.

We report here the preparation of flower-like Bi2WO6via a simple, rapid, microwave-assisted solution-phase process. Powder X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), field emission scanning electron microscopy (FE-SEM) and high resolution transmission electron microscopy (HRTEM) were employed to characterize the phase and morphologies of the products. The time-dependent experiments showed an Ostwald ripening mechanism in the crystal growth process. The as-prepared Bi2WO6 was able to efficiently degrade Rhodamine B (RhB) under visible light irradiation. Calcination was found to decrease the photocatalytic performance of flower-like Bi2WO6.

We report here the preparation of self-assembled persimmon-like (BiO)2CO3 microstructures via a simple hydrothermal process. Powder X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), field emission scanning electron microscopy (FE-SEM), selected area electron diffraction (SAED) and high resolution transmission electron microscopy (HRTEM) were employed to characterize the phases and morphologies of the products. The reactants could greatly influence the phases and morphologies of the final products. The growth process of the persimmon-like (BiO)2CO3 microstructures has been investigated. The persimmon-like (BiO)2CO3 could be utilized as a sacrificial template to synthesize sphere-like Bi2S3 microstructures by a chemical transformation process. The as-prepared (BiO)2CO3 was able to efficiently degrade Rhodamine B (RhB) and eosin sodium salt under simulated solar irradiation.

We explore X-ray spectral evolution and radio–X-ray correlation simultaneously for four X-ray binaries (XRBs). We find that hard X-ray photon indices, Γ, are anti- and positively correlated to X-ray fluxes when the X-ray flux, F3–9keV, is below and above a critical flux, FX,crit, which may be regulated by ADAF and disk-corona respectively. We find that the data points with anti-correlation of Γ-F3–9keV follow the universal radio–X-ray correlation of FR ∝ FXb (b ~ 0.5-0.7), while the data points with positive X-ray spectral evolution follow a steeper radio–X-ray correlation (b ~ 1.4, the so-called ‘outliers track’). The bright active galactic nuclei (AGNs) share similar X-ray spectral evolution and radio–X-ray correlation as XRBs in ‘outliers’ track, and we present a new fundamental plane of log LR=1.59+0.28−0.22 log LX−0.22+0.19−0.20 log MBH−28.97+0.45−0.45 for these radiatively efficient BH sources.

Nanoparticles-assembled BiFeO3 microrods were successfully prepared via a polymer-directed solvothermal route. The phase and morphology of the products were characterized by powder X-ray diffraction (XRD), energy dispersive spectrometry (EDS), inductively coupled plasma atomic emission spectroscopy (ICP-AES), FT-IR spectroscopy and scanning electron microscopy (SEM). Experiments indicated that the linking effect originated from the interactions between polymer molecules could direct the self-assembly of building blocks into one-dimensional nanoparticles-assembled BiFeO3 microrods. Some factors influencing the morphologies of the products were systematically investigated and a possible mechanism of the formation of the microrods was suggested. Moreover, the magnetic properties of the products were studied.

In the facial expression recognition system, owing to facial differences, the complexity of the organ distribution and the influence of the outside factors, the facial features location becomes a challenging task. Using the Kinect point distribution, we present a facial extraction algorithm of expression features, and carry out the related experiments. The experimental results show that the proposed methods have the significant advantage in the extracting features that are with unrelated deformation, non-sensitive to noise, or have a high degree of distinction.

In the present paper, we report successful synthesis of FeMoO4 hierarchical hollow spheres with 1.0 µm in diameter via a simple, rapid and reliable microwave-assisted solution-phase approach. The phases and morphologies of the products have been characterized by powder X-ray diffraction (XRD), energy dispersive spectrometry (EDS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Some factors influencing the morphology of the final product have been investigated. These experiments indicate that the self-assembly of FeMoO4 nanoparticles at the water/gas interface is responsible for the formation of a hierarchical hollow structure.

Under mild conditions, conversion of a variety of ketoximes and aldoximes to their corresponding amides and nitriles proceeded in the presence of PEG-SO 3 H with high yields.

YF3 with different crystalline phases and morphologies have been prepared via a facile hydrothermal route assisted by imidazolium ionic liquids 1-butyl-3-methylimidazolium tetrafluoroborate (C4mimBF4) or 1-butyl-3-methylimidazolium hexafluorophosphate (C4mimPF6). The microstructures and morphologies of YF3 particles were characterized by X-ray powder diffraction, X-ray photoelectron spectra (XPS), transmission electron microscopy (TEM), high resolution electron microscopy (HRTEM) and field emission scanning electron microscopy (FESEM). Cubic and orthorhombic YF3 were selectively synthesized by adjusting the molar ratio of the reagents and using C4mimBF4 as the fluoride source, while only orthorhombic YF3 was obtained using C4mimPF6, indicating that the crystalline phases and morphologies of the products were significantly influenced by fluoride source and reaction media.

A simple sonochemical procedure was developed to synthesize the flowerlike yttria precursor Y2(OH)5NO3·1.5H2O. Y2O3 with the same morphology was readily obtained by calcination of the precursor. The microstructures and morphologies of the products were characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectra (XPS), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and field-emission scanning electron microscopy (FESEM). The as-obtained Y2O3 and its precursor were found to be effective sorbents for the removal of Cr(VI) ions in water treatment, as a result of the novel hierarchical structures and high specific surface areas of these two materials.

A magnetic model for low/hard state (LHS) of black hole X-ray binaries (BHXBs),H1743-322 and GX 339-4, is proposed based on the transportation of magnetic field from a companion into an accretion disk around a black hole (BH). This model consists of a truncated thin disk with an inner advection-dominated accretion flow (ADAF). The spectral profiles of the sources are fitted in agreement with the data observed at four different dates corresponding to the rising phase of the LHS. In addition, the association of the LHS with quasi-steady jet is modelled based on transportation of magnetic field, where the Blandford-Znajek (BZ) and Blandford-Payne (BP) processes are invoked to drive the jets from BH and inner ADAF. It turns out that the steep radio/X-ray correlations observed in H1743-322 and GX 339-4 can be interpreted based on our model., 15 pages, 4 figures,accepted by RAA

In recent years, it was found that there are several low/hard state of X-ray binaries (XRBs) follow an `outliers' track of radio--X-ray correlation ($L_{\rm R}\propto L_{\rm X}^{b}$ and $b\sim1.4$), which is much steeper than the former universal track with $b\sim0.6$. In this work, we compile a sample of bright radio-quiet active galactic nuclei (AGNs) and find that their hard X-ray photon indices and Eddington ratios are positively correlated, which is similar to that of `outliers' of XRBs, where both bright AGNs and `outliers' of XRBs have bolometric Eddington ratios $\gtrsim1%L_{\rm Edd}$ ($L_{\rm Edd}$ is Eddington luminosity). The Eddington-scaled radio--X-ray correlation of these AGNs is also similar to that of `outliers' of XRBs, which has a form of $L_{\rm 5 GHz}/L_{\rm Edd}\propto (L_{\rm 2-10 keV}/L_{\rm Edd})^{c}$ with $c\simeq1.59$ and 1.53 for AGNs and XRBs respectively. Both the positively correlated X-ray spectral evolution and the steeper radio--X-ray correlation can be regulated by a radiatively efficient accretion flow (e.g., disk-corona). Based on these similarities, we further present a new fundamental plane for `outliers' of XRBs and bright AGNs in black-hole (BH) mass, radio and X-ray luminosity space: $\log L_{\rm R}=1.59^{+0.28}_{-0.22} \log L_{\rm X}- 0.22^{+0.19}_{-0.20}\log M_{\rm BH}-28.97^{+0.45}_{-0.45}$ with a scatter of $\sigma_{\rm R}=0.51\rm dex$. This fundamental plane is suitable for radiatively efficient BH sources, while the former plane proposed by Merloni et al. and Falcke et al. may be most suitable for radiatively inefficient sources., Comment: Accepted for publication in ApJ Letter; emulateapj format; 6 pages, 3 figures, 1 table

Root hairs of Arabidopsis roots develop on trichoblasts located over the anticlinal (radial) walls of underlying cortical cells. Non-hair cells, on the other hand, develop on atrichoblasts overlying the periclinal (tangential) walls of cortical cells. Dark-grown wild-type seedlings, which produce little ethylene, are largely root hairless. Exogenous treatment of dark-grown plants with either ethylene or 1-aminocyclopropane-1-carboxylic acid (ACC) restores the development of root hairs in cells overlying the anticlinal cortical cell walls, indicating that cells in this position are more sensitive to ethylene than atrichoblasts. We used mutations in genes that overproduce ethylene (eto1, eto2, eto3 and eto4) to illustrate the positive regulatory role of ethylene. The preferential development of root hairs on epidermal cells overlying the cortical anticlinal cell walls in these mutants also illustrates that trichoblasts are more sensitive to ethylene than atrichoblasts. CTR1 is a negative regulator of the ethylene response and might, therefore, be a candidate regulator of differential sensitivity. CTR1 mRNA is expressed in all cell types in the root, suggesting that its transcriptional pattern alone cannot account for the differential sensitivity of epidermal cells to ethylene. Cellular mapping of wild-type and mutant roots supports previous findings indicating that ethylene acts after, and perhaps independently, of TTG during the establishment of cell fate in the root epidermis.

The determination of luminosity function (LF) of gamma-ray bursts (GRBs) is of an important role for the cosmological applications of the GRBs, which is however hindered seriously by some selection effects due to redshift measurements. In order to avoid these selection effects, we suggest to calculate pseudo-redshifts for Swift GRBs according to the empirical L-E_p relationship. Here, such a $L-E_p$ relationship is determined by reconciling the distributions of pseudo- and real redshifts of redshift-known GRBs. The values of E_p taken from Butler's GRB catalog are estimated with Bayesian statistics rather than observed. Using the GRB sample with pseudo-redshifts of a relatively large number, we fit the redshift-resolved luminosity distributions of the GRBs with a broken-power-law LF. The fitting results suggest that the LF could evolve with redshift by a redshift-dependent break luminosity, e.g., L_b=1.2\times10^{51}(1+z)^2\rm erg s^{-1}. The low- and high-luminosity indices are constrained to 0.8 and 2.0, respectively. It is found that the proportional coefficient between GRB event rate and star formation rate should correspondingly decrease with increasing redshifts., 5 pages, 5 figures, accepted for publication in ApJL

Maillard reaction products (MRPs) were prepared by heating the solution containing L-ascorbic acid (ASA) and L Methionine(Met) adjusted to various pHs (4, 5, 6, 7 and 8) at 140°C for different times (100, 200, 300, 400 and 500 min). The pH of MRPs derived from ASA-Met model systems markedly changed within 100 min of heating time. Browning and intermediate products, as monitored by absorbance at 420 nm and absorbance at 294 nm, sharply increased within 100 200 min (P

Swift observations suggest that the central compact objects of some gamma-ray bursts (GRBs) could be newly born millisecond magnetars. Therefore, by considering the spin evolution of the magnetars against r-mode instability, we investigate the role of the magnetars in GRB X-ray afterglow emission. Besides modifying the conventional energy injection model, we pay particular attention to the internal X-ray afterglow emission, whose luminosity is assumed to track the magnetic dipole luminosity of the magentars with a certain fraction. Following a comparison between the model and some selected observational samples, we suggest that some so-called "canonical" X-ray afterglows including the shallow decay, normal decay, and steeper-than-normal decay phases could be internally produced by the magnetars (possibly through some internal dissipations of the magnetar winds), while the (energized) external shocks are associated with another type of X-ray afterglows. If this is true, from those internal X-ray afterglows, we can further determine the magnetic field strengths and the initial spin periods of the corresponding magnetars., 10 pages, 5 figures, accepted for publication in ApJ

Under mild conditions, conversion of a variety of ketoximes and aldoximes to their corresponding amides and nitriles proceeded in the presence of PEG-SO 3 H with high yields.

The internal-plateau X-ray emission of gamma-ray bursts (GRBs) indicates that a newly born magnetar could be the central object of some GRBs. The observed luminosity and duration of the plateaus suggest that, for such a magnetar, a rapid spin with a sub- or millisecond period is sometimes able to last thousands of seconds. In this case, the conventional neutron star (NS) model for the magnetar may be challenged, since the rapid spin of nascent NSs would be remarkably decelerated within hundreds of seconds due to r-mode instability. In contrast, the r-modes can be effectively suppressed in nascent strange stars (SSs). In other words, to a certain extent, only SSs can keep nearly-constant extremely-rapid spin for a long period of time during the early ages of the stars. We thus propose that the sample of the GRB rapidly-spinning magnetars can be used to test the SS hypothesis based on the distinct spin limits of NSs and SSs., Comment: 5 pages, 2 figures, accepted for publication in ApJ Letters

Recently an `outliers' track of radio-X-ray correlation was found, which is much steeper than the former universal correlation, where dual tracks were speculated to be triggered by different accretion processes. In this work, we test this issue by exploring hard X-ray spectral evolution in four black-hole X-ray binaries (XRBs) with multiple, quasi-simultaneous radio and X-ray observations. Firstly, we find that hard X-ray photon indices, $\Gamma$, are anti- and positively correlated to X-ray fluxes when the X-ray flux, $F_{\rm 3-9keV}$, is below and above a critical flux, $F_{\rm X,crit}$, which are consistent with prediction of advection dominated accretion flow (ADAF) and disk-corona model respectively. Secondly and most importantly, we find that the radio-X-ray correlations are also clearly different when the X-ray fluxes are higher and lower than the critical flux that defined by X-ray spectral evolution. The data points with $F_{\rm 3-9keV}\gtrsim F_{\rm X,crit}$ have a steeper radio-X-ray correlation ($F_{\rm X}\propto F_{\rm R}^{b}$ and $b\sim 1.1-1.4$), which roughly form the `outliers' track. However, the data points with anti-correlation of $\Gamma-F_{\rm 3-9keV}$ either stay in the universal track with $b\sim0.61$ or stay in transition track (from the universal to `outliers' tracks or vice versa). Therefore, our results support that the universal and `outliers' tracks of radio-X-ray correlations are regulated by radiatively inefficient and radiatively efficient accretion model respectively., Comment: Accepted for publication in ApJ; 10 pages, 5 figures, 5 tables

Monodisperse erythrocyte-like Cd2Ge2O6 superstructures have been successfully prepared via a facile and fast microwave-assisted solution-phase approach, employing Cd(Ac)2·2H2O and GeO2 as the reactants in the presence of hydrazine monohydrate. The phase and morphology of the product were characterized by powder X-ray diffraction (XRD), X-ray photoelectron spectrum (XPS), energy dispersive spectrometry (EDS), selected area electron diffraction (SAED), high resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM). Such monoclinic phase Cd2Ge2O6 microstructures were found to be constructed by abundant single crystalline nanoneedles. Some influencing factors such as the reaction time, reaction temperature, the volume of hydrazine monohydrate and the cadmium source were revealed to play crucial roles in the formation of the Cd2Ge2O6 architecture. A possible growth mechanism was proposed based on the experimental results.

Well-aligned Zn2GeO4 nanorod bundles were successfully prepared via a facile microwave-assisted solution-phase approach. The phase and morphology of the product were characterized by powder X-ray diffraction (XRD), energy dispersive spectrometry (EDS), selected area electron diffraction (SAED), high resolution transmission electron microscopy (HRTEM), and scanning electron microscopy (SEM). Such rhombohedral phase Zn2GeO4 bundle-like microstructures were found to be constructed by abundant single crystalline nanorods of 40–70 nm in diameter and ∼800 nm in length. Some influencing factors such as the reaction time, temperature, the volume of ethylenediamine and PEG-400 were revealed to play crucial roles in the formation of Zn2GeO4 nanobundles. A possible growth mechanism was proposed based on the experimental results. Moreover, the photocatalytic properties of as-prepared Zn2GeO4 nanobundles were studied, and they exhibited excellent photocatalytic activities for degradation of methyl orange and rhodamine B under UV light irradiation.

A fast and economical route based on microwave-assisted hydrothermal reaction has been developed to synthesize pancake-like Fe2(MoO4)3 microstructures. The phase and morphology of the products have been characterized by powder X-ray diffraction (XRD), energy dispersive spectrometry (EDS), selected area electron diffraction (SAED), high resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM). Several factors, including the amount of nitric acid, reaction time, temperature and iron source, play crucial roles in the formation of the Fe2(MoO4)3 multilayer stacked structures. Detailed studies indicate that the oriented attachment and layer-by-layer self-assembly of nanosheets is responsible for the formation of these structures. The magnetic and photocatalytic properties of the product have also been investigated.