Tianjin Normal University

The final product of galaxy evolution through cosmic time is the population of galaxies in the local universe. These galaxies are also those that can be studied in most detail, thus providing a stringent benchmark for our understanding of galaxy evolution. Through the huge success of spectroscopic single-fiber, statistical surveys of the Local Universe in the last decade, it has become clear, however, that an authoritative observational description of galaxies will involve measuring their spatially resolved properties over their full optical extent for a statistically significant sample. We present here the Calar Alto Legacy Integral Field Area (CALIFA) survey, which has been designed to provide a first step in this direction. We summarize the survey goals and design, including sample selection and observational strategy. We also showcase the data taken during the first observing runs (June/July 2010) and outline the reduction pipeline, quality control schemes and general characteristics of the reduced data.

A mis nietos.V

As an emerging class of porous crystalline materials, covalent organic frameworks (COFs) are excellent candidates for various applications. In particular, they can serve as ideal platforms for capturing CO2 to mitigate the dilemma caused by the greenhouse effect. Recent research achievements using COFs for CO2 capture are highlighted. A background overview is provided, consisting of a brief statement on the current CO2 issue, a summary of representative materials utilized for CO2 capture, and an introduction to COFs. Research progresses on: i) experimental CO2 capture using different COFs synthesized based on different covalent bond formations, and ii) computational simulation results of such porous materials on CO2 capture are summarized. Based on these experimental and theoretical studies, careful analyses and discussions in terms of the COF stability, low- and high-pressure CO2 uptake, CO2 selectivity, breakthrough performance, and CO2 capture conditions are provided. Finally, a perspective and conclusion section of COFs for CO2 capture is presented. Recent advancements in the field are highlighted and the strategies and principals involved are discussed.

Abstract Ti 3 C 2 T x , a typical representative among the emerging family of 2D layered transition metal carbides and/or nitrides referred to as MXenes, has exhibited multiple advantages including metallic conductivity, a plastic layer structure, small band gaps, and the hydrophilic nature of its functionalized surface. As a result, this 2D material is intensively investigated for application in the energy storage field. The composition, morphology and texture, surface chemistry, and structural configuration of Ti 3 C 2 T x directly influence its electrochemical performance, e.g., the use of a well‐designed 2D Ti 3 C 2 T x as a rechargeable battery anode has significantly enhanced battery performance by providing more chemically active interfaces, shortened ion‐diffusion lengths, and improved in‐plane carrier/charge‐transport kinetics. Some recent progresses of Ti 3 C 2 T x MXene are achieved in energy storage. This Review summarizes recent advances in the synthesis and electrochemical energy storage applications of Ti 3 C 2 T x MXene including supercapacitors, lithium‐ion batteries, sodium‐ion batteries, and lithium–sulfur batteries. The current opportunities and future challenges of Ti 3 C 2 T x MXene are addressed for energy‐storage devices. This Review seeks to provide a rational and in‐depth understanding of the relation between the electrochemical performance and the nanostructural/chemical composition of Ti 3 C 2 T x , which will promote the further development of 2D MXenes in energy‐storage applications.

Abstract Zinc‐ion batteries (ZIBs) are regarded as a promising candidate for next‐generation energy storage systems due to their high safety, resource availability, and environmental friendliness. Nevertheless, the instability of the Zn metal anode has impeded ZIBs from being reliably deployed in their proposed applications. Specifically, dendrite formation and the hydrogen evolution reaction (HER) on the Zn surface significantly compromise the Coulombic efficiency and cycling stability of ZIBs. In recent years, increasing efforts have been devoted to overcoming these obstacles by electrode structure design, interface modification, and electrolyte/separator optimization. To achieve an insightful and comprehensive understanding of these strategies, it is worth analyzing and categorizing them according to their intrinsic mechanisms. Considering this, an overview of the anodic stabilization strategies is provided. First, the fundamentals of the Zn metal anode are introduced, and the associated reaction mechanisms are presented. Furthermore, strategies of dendrite and HER suppression are categorized, discussed, and analyzed in detail. Last, suggestions for Zn anode deployment in ZIBs from research, industrialization, and commercialization aspects are proposed. It is expected that this Review and the proposed strategies will shed light on the roadmap for the exploration of novel Zn metal anodes for ZIBs.

Mixed transition‐metal oxides (MTMOs), including stannates, ferrites, cobaltates, and nickelates, have attracted increased attention in the application of high performance lithium‐ion batteries. Compared with traditional metal oxides, MTMOs exhibit enormous potential as electrode materials in lithium‐ion batteries originating from higher reversible capacity, better structural stability, and high electronic conductivity. Recent advancements in the rational design of novel MTMO micro/nanostructures for lithium‐ion battery anodes are summarized and their energy storage mechanism is compared to transition‐metal oxide anodes. In particular, the significant effects of the MTMO morphology, micro/nanostructure, and crystallinity on battery performance are highlighted. Furthermore, the future trends and prospects, as well as potential problems, are presented to further develop advanced MTMO anodes for more promising and large‐scale commercial applications of lithium‐ion batteries.

Using free–free emission measured in the Ka band (26–40 GHz) for 10 star-forming regions in the nearby galaxy NGC 6946, including its starbursting nucleus, we compare a number of star formation rate (SFR) diagnostics that are typically considered to be unaffected by interstellar extinction. These diagnostics include non-thermal radio (i.e., 1.4 GHz), total infrared (IR; 8–1000 μm), and warm dust (i.e., 24 μm) emission, along with hybrid indicators that attempt to account for obscured and unobscured emission from star-forming regions including Hα + 24 μm and UV + IR measurements. The assumption is made that the 33 GHz free–free emission provides the most accurate measure of the current SFR. Among the extranuclear star-forming regions, the 24 μm, Hα + 24 μm, and UV + IR SFR calibrations are in good agreement with the 33 GHz free–free SFRs. However, each of the SFR calibrations relying on some form of dust emission overestimates the nuclear SFR by a factor of ∼2 relative to the 33 GHz free–free SFR. This is more likely the result of excess dust heating through an accumulation of non-ionizing stars associated with an extended episode of star formation in the nucleus rather than increased competition for ionizing photons by dust. SFR calibrations using the non-thermal radio continuum yield values which only agree with the 33 GHz free–free SFRs for the nucleus and underestimate the SFRs from the extranuclear star-forming regions by an average factor of ∼2 and ∼4–5 before and after subtracting local background emission, respectively. This result likely arises from the cosmic-ray (CR) electrons decaying within the starburst region with negligible escape, whereas the transient nature of star formation in the young extranuclear star-forming complexes allows for CR electrons to diffuse significantly further than dust-heating photons, resulting in an underestimate of the true SFR. Finally, we find that the SFRs estimated using the total 33 GHz flux density appear to agree well with those estimated using free–free emission due to the large thermal fractions present at these frequencies even when local diffuse backgrounds are not removed. Thus, rest-frame 33 GHz observations may act as a reliable method to measure the SFRs of galaxies at increasingly high redshift without the need of ancillary radio data to account for the non-thermal emission.

Solvent effect is a vital subject in the domain of coordination chemistry. In this connection, previous researches mainly focus on the role of solvents in reaction kinetics and thermodynamics during the coordination processes. In virtue of the recent efforts on coordination supramolecular systems, especially coordination polymers or metal-organic frameworks, this feature article aims to demonstrate the solvent effect on regulating such diversiform metallosupramolecular solids, incorporating their crystal growth/assembly, structural modulation, dynamic transformations, and potential applications, which may provide new insights into the rational design and construction of such advanced crystalline materials.

We present new calibrations of far-ultraviolet (FUV) attenuation as derived from the total infrared to FUV luminosity ratio (IRX) and the FUV–near-UV(NUV) color. We find that the IRX-corrected FUV luminosities are tightly and linearly correlated with the attenuation-corrected Hα luminosities (as measured from the Balmer decrement), with an rms scatter of ±0.09 dex. The ratios of these attenuation-corrected FUV to Hα luminosities are consistent with evolutionary synthesis model predictions, assuming a constant star formation rate over 100 Myr, solar metallicity, and either a Salpeter or a Kroupa initial mass function with lower and upper mass limits of 0.1 and 100 M ☉ . The IRX-corrected FUV to Balmer-corrected Hα luminosity ratios do not show any trend with other galactic properties over the ranges covered by our sample objects. In contrast, FUV attenuation derived from the FUV–NUV color (UV spectral slope) show much larger random and systematic uncertainties. When compared to either Balmer-corrected Hα luminosities or IRX-corrected FUV luminosities the color-corrected FUV luminosities show ∼2.5 times larger rms scatter, and systematic nonlinear deviations as functions of luminosity and other parameters. Linear combinations of 25 μm and 1.4 GHz radio continuum luminosities with the observed FUV luminosities are also well correlated with the Balmer-corrected Hα luminosities. These results provide useful prescriptions for deriving attenuation-corrected star formation rates of galaxies based on linear combinations of UV and IR or radio luminosities, which are presented in convenient tabular form. Comparisons of our calibrations with attenuation corrections in the literature and with dust attenuation laws are also made.

Abstract As a type of energy storage device between traditional capacitors and batteries, the supercapacitor has the advantages of energy saving and environmental protection, high power density, fast charging and discharging speed, long cycle life, and so forth. One of the key factors affecting the performance of supercapacitor is the electrode material. Carbon materials, such as carbon nanotube, graphene, activated carbon, and carbon nanocage, are most widely concerned in the application of supercapacitors. The synergistic effect of composites can often obtain excellent results, which is one of the common strategies to increase the electrochemical performance of supercapacitors. To further improve the performance of binary composites, it is a relatively simple method to increase the components as the “bridge” between the two materials to form the ternary composites. The review mainly introduces the current research progress of supercapacitors with pure carbon nanomaterials and multistage carbon nanostructures (composites) as electrodes. The characteristics and application directions of different pure carbon nanomaterials are introduced in detail. Different ways of multilevel structure (material) composite have their own effects on the development of high‐performance supercapacitors. We also highlight the recent advances related to these fields and provide our insight into high‐energy supercapacitors.

TikTok (in Chinese: DouYin; formerly known as musical.ly) currently represents one of the most successful Chinese social media applications in the world. Since its founding in September 2016, TikTok has seen widespread distribution, in particular, attracting young users to engage in viewing, creating, and commenting on "LipSync-Videos" on the app. Despite its success in terms of user numbers, psychological studies aiming at an understanding of TikTok use are scarce. This narrative review provides a comprehensive overview on the small empirical literature available thus far. In particular, insights from uses and gratification theory in the realm of TikTok are highlighted, and we also discuss aspects of the TikTok platform design. Given the many unexplored research questions related to TikTok use, it is high time to strengthen research efforts to better understand TikTok use and whether certain aspects of its use result in detrimental behavioral effects. In light of user characteristics of the TikTok platform, this research is highly relevant because TikTok users are often adolescents and therefore from a group of potentially vulnerable individuals.

Covalent organic frameworks (COFs) are excellent platforms with tailored functionalities in photocatalysis. There are still challenges in increasing the photochemical performance of COFs. Therefore, we designed and prepared a series of COFs for photocatalytic hydrogen generation. Varying different ratios of β-ketoenamine to imine moieties in the linkages could differ the ordered structure, visible light harvesting, and bandgap. Overall, β-ketoenamine-linked COFs exhibited much better photocatalytic activity than those COFs having both β-ketoenamine and imine moieties on account of a nonquenched excited state and more favorable HOMO level in the photoinduced oxidation reaction from the former. Specifically, after in situ growth of β-ketoenamine-linked COFs onto NH 2 –Ti 3 C 2 T x MXene via covalent connection, the heterohybrid showed an obvious improvement in photocatalytic H 2 evolution because of strong covalent coupling, electrical conductivity, and efficient charge transfer. This integrated linkage evolution and covalent hybridization approach advances the development of COF-based photocatalysts.

Since increase in exportsis highlybeneficial for the economic development and growth of a country, this research exposes the negative effects of a brand’s country-of-origin on consumer purchase intention in developing countries, it exposes how a brand’s country- of-origin in developing countries influences local consumers to purchase imported brands more than local brands. Through the use of a quantitative research method, this research is based on data collected from a sample size of 600 that was analyzed in SPSS. The findings shows that country-of-origin influences the purchase of local and imported FMCGs in Zambia, but its effects are much stronger towards the purchase of imported goods than local goods. Furthermore, the results also reveal that Zambians are prone to purchase imported goods because they trust them. These findings therefore provide empirical evidence of the importance of the need for more studies and usage of country-of-origin and brand trust in marketing research and practice in developing countries.

The KINGFISH project (Key Insights on Nearby Galaxies: a Far-Infrared Survey with Herschel ) is an imaging and spectroscopic survey of 61 nearby ( d < 30 Mpc) galaxies, chosen to cover a wide range of galaxy properties and local interstellar medium (ISM) environments found in the nearby universe. Its broad goals are to characterize the ISM of present-day galaxies, the heating and cooling of their gaseous and dust components, and to better understand the physical processes linking star formation and the ISM. KINGFISH is a direct descendant of the Spitzer Infrared Nearby Galaxies Survey (SINGS), which produced complete Spitzer imaging and spectroscopic mapping and a comprehensive set of multiwavelength ancillary observations for the sample. The Herschel imaging consists of complete maps for the galaxies at 70, 100, 160, 250, 350, and 500 μm. The spectral line imaging of the principal atomic ISM cooling lines ([O I ] 63 μm, [O III ] 88 μm, [N II ] 122,205 μm, and [C II ] 158 μm) covers the subregions in the centers and disks that already have been mapped in the mid-infrared with Spitzer . The KINGFISH and SINGS multiwavelength data sets combined provide panchromatic mapping of the galaxies sufficient to resolve individual star-forming regions, and tracing the important heating and cooling channels of the ISM, across a wide range of local extragalactic ISM environments. This article summarizes the scientific strategy for KINGFISH, the properties of the galaxy sample, the observing strategy, and data processing and products. It also presents a combined Spitzer and Herschel image atlas for the KINGFISH galaxies, covering the wavelength range 3.6–500 μm. All imaging and spectroscopy data products will be released to the Herschel user-generated product archives.

Intrusion detection can identify unknown attacks from network traffics and has been an effective means of network security. Nowadays, existing methods for network anomaly detection are usually based on traditional machine learning models, such as KNN, SVM, etc. Although these methods can obtain some outstanding features, they get a relatively low accuracy and rely heavily on manual design of traffic features, which has been obsolete in the age of big data. To solve the problems of low accuracy and feature engineering in intrusion detection, a traffic anomaly detection model BAT is proposed. The BAT model combines BLSTM (Bidirectional Long Short-term memory) and attention mechanism. Attention mechanism is used to screen the network flow vector composed of packet vectors generated by the BLSTM model, which can obtain the key features for network traffic classification. In addition, we adopt multiple convolutional layers to capture the local features of traffic data. As multiple convolutional layers are used to process data samples, we refer BAT model as BAT-MC. The softmax classifier is used for network traffic classification. The proposed end-to-end model does not use any feature engineering skills and can automatically learn the key features of the hierarchy. It can well describe the network traffic behavior and improve the ability of anomaly detection effectively. We test our model on a public benchmark dataset, and the experimental results demonstrate our model has better performance than other comparison methods.

Metal–organic frameworks are a class of attractive materials for fluorescent sensing. Improvement of hydrolytic stability, sensitivity, and selectivity of function is the key to advance application of fluorescent MOFs in aqueous media. In this work, two stable MOFs, [Zr 6 O 4 (OH) 8 (H 2 O) 4 (L 1 ) 2 ] (BUT-14) and [Zr 6 O 4 (OH) 8 (H 2 O) 4 (L 2 ) 2 ] (BUT-15), were designed and synthesized for the detection of metal ions in water. Two new ligands utilized for construction of the MOFs, namely, 5′,5‴-bis(4-carboxyphenyl)-[1,1′:3′,1″:4″,1‴:3‴,1′′′′-quinquephenyl]-4,4′′′′-dicarboxylate (L 1 ) and 4,4′,4″,4‴-(4,4′-(1,4-phenylene)bis(pyridine-6,4,2-triyl))tetrabenzoate (L 2 ), are structurally similar with the only difference being that the latter is functionalized by pyridine N atoms. The two MOFs are isostructural with a sqc - a topological framework structure, and highly porous with the Brunauer–Emmett–Teller (BET) surface areas of 3595 and 3590 m 2 g –1, respectively. Interestingly, they show intense fluorescence in water, which can be solely quenched by trace amounts of Fe 3+ ions. The detection limits toward the Fe 3+ ions were calculated to be 212 and 16 ppb, respectively. The efficient fluorescent quenching effect is attributed to the photoinduced electron transfer between Fe 3+ ions and the ligands in these MOFs. Moreover, the introduced pyridine N donors in the ligand of BUT-15 additionally donate their lone-pair electrons to the Fe 3+ ions, leading to significantly enhanced detection ability. It is also demonstrated that BUT-15 exhibits an uncompromised performance for the detection of Fe 3+ ions in a simulated biological system.

Spitzer data at 24, 70, and 160 μm and ground-based Hα images are analyzed for a sample of 189 nearby star-forming and starburst galaxies to investigate whether reliable star formation rate (SFR) indicators can be defined using the monochromatic infrared dust emission centered at 70 and 160 μm. We compare recently published recipes for SFR measures using combinations of the 24 μm and observed Hα luminosities with those using 24 μm luminosity alone. From these comparisons, we derive a reference SFR indicator for use in our analysis. Linear correlations between SFR and the 70 μm and 160 μm luminosity are found for L (70) ≳ 1.4 × 10 42 erg s −1 and L (160) ≳ 2 × 10 42 erg s −1 , corresponding to SFR ≳ 0.1–0.3 M ☉ yr −1 , and calibrations of SFRs based on L (70) and L (160) are proposed. Below those two luminosity limits, the relation between SFR and 70 μm (160 μm) luminosity is nonlinear and SFR calibrations become problematic. A more important limitation is the dispersion of the data around the mean trend, which increases for increasing wavelength. The scatter of the 70 μm (160 μm) data around the mean is about 25% (factor ∼2) larger than the scatter of the 24 μm data. We interpret this increasing dispersion as an effect of the increasing contribution to the infrared emission of dust heated by stellar populations not associated with the current star formation. Thus, the 70 (160) μm luminosity can be reliably used to trace SFRs in large galaxy samples, but will be of limited utility for individual objects, with the exception of infrared-dominated galaxies. The nonlinear relation between SFR and the 70 and 160 μm emission at faint galaxy luminosities suggests a variety of mechanisms affecting the infrared emission for decreasing luminosity, such as increasing transparency of the interstellar medium, decreasing effective dust temperature, and decreasing filling factor of star-forming regions across the galaxy. In all cases, the calibrations hold for galaxies with oxygen abundance higher than roughly 12 +log(O/H) ∼ 8.1. At lower metallicity, the infrared luminosity no longer reliably traces the SFR because galaxies are less dusty and more transparent.

Copper-catalyzed reaction of diazo compounds generates copper carbene intermediates that undergo diverse transformations. In recent years, the selectivity and efficiency of these important conversions have been further improved. In particular, breakthroughs have been made in catalytic asymmetric polar X-H bond insertion reactions. Moreover, novel transformations based on copper carbene, namely copper-catalyzed cross-couplings of diazo compounds, have emerged as powerful methods for carbon-carbon bond formations. This feature article summarizes the most recent developments in this area.

INTRODUCTION: Prior research has found that psychopathology constructs such as depression and anxiety are associated with problematic use of Facebook (PFU). In the present study, we examined a structural equation model whereby depression, social anxiety and lower life satisfaction predicted PFU severity, while analyzing mediating variables including rumination, fear of missing out (FoMO), and frequency of Facebook use, as well as age and gender as covariates. METHOD: Participants were 296 college students administered a web survey of instruments measuring these constructs. RESULTS: Modeling results demonstrate that FoMO and rumination were significantly related to PFU severity. Facebook use frequency was related to PFU severity. FoMO and rumination each mediated relations between social anxiety and PFU severity. CONCLUSIONS: Results are discussed in the context of prior work on FoMO and excessive technology use, as well as several relevant theoretical frameworks.

Tailored dopant strategies are proposed to optimise the energy density of BiFeO 3 –SrTiO 3 , which can be adapted for other high polarisability oxide-based systems.