The Clumpy Structure of Five Star-bursting Dwarf Galaxies in the MaNGA Survey

The star-forming clumps in star-bursting dwarf galaxies provide valuable insights into understanding the evolution of dwarf galaxies.In this paper,we focus on five star-bursting dwarf galaxies featuring off-centered clumps in the Mapping Nearby Galaxies at Apache Point Observatory survey.Using the stellar population synthesis software Fitting Analysis using Differential evolution Optimization,we obtain the spatially resolved distribution of the star formation history,which allows us to construct the g-band images of the five galaxies at different ages.These images can help us to probe the evolution of the morphological structures of these galaxies.While images of a stellar population older than 1 Gyr are typically smooth,images of a stellar population younger than 1 Gyr reveal significant clumps,including multiple clumps which appear at different locations and even different ages.To study the evolutionary connections of these five galaxies to other dwarf galaxies before their star-forming clumps appear,we construct the images of the stellar populations older than three age nodes,and define them to be the images of the"host"galaxies.We find that the properties such as the central surface brightness and the effective radii of the hosts of the five galaxies are in between those of dwarf ellipticals(dEs)and dwarf irregulars(dIrrs),with two clearly more similar to dEs and one more similar to dIrrs.Among the five galaxies,8257-3704 is particularly interesting,as it shows a previous starburst event that is not quite visible from its gri image,but only visible from images of the stellar population at a few hundred million years.The star-forming clump associated with this event may have appeared at around 600 Myr ago and disappeared at around 40 Myr ago.

Towards magnetism in pigeon MagR: Iron- and iron-sulfur binding work indispensably and synergistically

The ability to navigate long distances is essential for many animals to locate shelter,food,and breeding grounds.Magnetic sense has evolved in various migratory and homing species to orient them based on the geomagnetic field.A highly conserved ironsulfur cluster assembly protein IscA is proposed as an animal magnetoreceptor(MagR).Iron-sulfur cluster binding is also suggested to play an essential role in MagR magnetism and is thus critical in animal magnetoreception.In the current study,we provide evidence for distinct iron binding and iron-sulfur cluster binding in MagR in pigeons,an avian species that relies on the geomagnetic field for navigation and homing.Pigeon MagR showed significantly higher total iron content from both iron-and ironsulfur binding.Y65 in pigeon MagR was shown to directly mediate mononuclear iron binding,and its mutation abolished iron-binding capacity of the protein.Surprisingly,both iron binding and iron-sulfur binding demonstrated synergistic effects,and thus appear to be integral and indispensable to pigeon MagR magnetism.These results not only extend our current understanding of the origin and complexity of MagR magnetism,but also imply a possible molecular explanation for the huge diversity in animal magnetoreception.

High piezo/photocatalytic efficiency of Ag/Bi_(5)O_(7)I nanocomposite using mechanical and solar energy for N2 fixation and methyl orange degradation

In this work,Ag/Bi_(5)O_(7)I nanocomposite was prepared and firstly applied in piezo/photocatalytic reduction of N2 to NH3 and methyl orange(MO)degradation.Bi_(5)O_(7)I was synthesized via a hydrothermal-calcination method and shows nanorods morphology.Ag nanoparticles(NPs)were photo deposited on the Bi_(5)O_(7)I nanorods as electron trappers to improve the spatial separation of charge carriers,which was confirmed via XPS,TEM,and electronic chemical analyses.The catalytic test indicates that Bi_(5)O_(7)I presents the piezoelectric-like behavior,while the loading of Ag NPs can strengthen the character.Under ultrasonic vibration,the optimal Ag/Bi_(5)O_(7)I presents high efficiency in MO degradation.The degradation rate is determined to be 0.033 min
1,which is 4.7 folds faster than that of Bi_(5)O_(7)I.The Ag/Bi_(5)O_(7)I also presents a high performance in piezocatalytic N2 fixation.The piezocatalytic NH3 generation rate reaches 65.4 μmol L^(-1)g^(-1)h^(-1)with water as a hole scavenger.The addition of methanol can hasten the piezoelectric catalytic reaction.Interestingly,when ultrasonic vibration and light irradiation simultaneously act on the Ag/Bi_(5)O_(7)I catalyst,higher performance in NH3 generation and MO degradation is observed.However,due to the weak adhesion of Ag NPs,some Ag NPs would fall off from the Bi_(5)O_(7)I surface under long-term ultrasonic vibration,which would greatly reduce the piezoelectric catalytic performance.This result indicates that a strong binding force is required when preparing the piezoelectric composite catalyst.The current work provides new insights for the development of highly efficient catalysts that can use multiple energies.

The Unusual AGN Host NGC 1266:Evidence for Shocks in a Molecular Gas Rich S0 Galaxy with a Low Luminosity Nucleus

NGC 1266 is a lenticular galaxy(S0)hosting an active galactic nucleus(AGN),and known to contain a large amount of shocked gas.We compare the luminosity ratio of mid-J CO lines to IR continuum with star-forming galaxies(SFGs),and then model the CO spectral line energy distribution(SLED).We confirm that in the mid-and high-J regions(J_(up)=4-13),the C-type shock(v_(s)=25 km s^(-1),n_(H)=5×10^(4)cm^(-3))can reproduce the CO observations well.The galaxy spectral energy distribution(SED)is constructed and modeled by the code X-CIGALE and obtains a set of physical parameters including the star formation rate(SFR,1.17±0.47 M_(⊙)yr^(-1)).Also,our work provides SFR derivation of[C II]from the neutral hydrogen regions only(1.38±0.14 M_(⊙)yr^(-1)).Previous studies have illusive conclusions on the AGN or starburst nature of the NGC 1266 nucleus.Our SED model shows that the hidden AGN in the system is intrinsically low-luminosity,consequently the infrared luminosity of the AGN does not reach the expected level.Archival data from Nu STAR hard X-ray observations in the 3-79 keV band shows a marginal detection,disfavoring presence of an obscured luminous AGN and implying that a compact starburst is more likely dominant for the NGC 1266 nucleus.

Facile preparation of Ag_(2)S/KTa_(0.5)Nb_(0.5)O_(3) heterojunction for enhanced performance in catalytic nitrogen fixation via photocatalysis and piezo-photocatalysis

In this work, a novel heterojunction composite Ag_(2)S/KTa_(x)Nb_(1-x)O_(3)was designed and synthesized through a combination of hydrothermal and precipitation procedures. The Ta/Nb ratio of the KTa_(x)Nb_(1-x)O_(3)and the Ag_(2)S content were optimized. The best 0.5% Ag_(2)S/KTa_(0.5)Nb_(0.5)O_(3)(KTN) sample presents an enhanced photocatalytic performance in ammonia synthesis than KTN and Ag_(2)S. Under simulated sunlight, the NH_(3)generation rate of 0.5% Ag_(2)S/KTN reaches 2.0 times that of pure KTN. Under visible light, the reaction rate ratio of the two catalysts is 6.0.XRD, XPS, and TEM analysis revealed that Ag2S was intimately decorated on the KTN nanocubes surface, which promoted the electron transfer between the two semiconductors. The band structure investigation indicated that the Ag_(2)S/KTN heterojunction established a type-Ⅱ band alignment with intimate contact, thus realizing the effective transfer and separation of photogenerated carriers. The change in charge separation was considered as the main reason for the enhanced photocatalytic performance. Interestingly, the Ag_(2)S/KTN composite exhibited higher NH3generation performance under the combined action of ultrasonic vibration and simulated sunlight. The enhanced piezo-photocatalytic performance can be ascribed that the piezoelectric effect of KTN improved the bulk separation of charge carriers in KTN. This study not only provides a potential catalyst for photocatalytic nitrogen fixation but also shows new ideas for the design of highly efficient catalysts via semiconductor modification and external field coupling.

Attack Behavior Extraction Based on Heterogeneous Cyberthreat Intelligence and Graph Convolutional Networks

The continuous improvement of the cyber threat intelligence sharing mechanism provides new ideas to deal with Advanced Persistent Threats(APT).Extracting attack behaviors,i.e.,Tactics,Techniques,Procedures(TTP)from Cyber Threat Intelligence(CTI)can facilitate APT actors’profiling for an immediate response.However,it is difficult for traditional manual methods to analyze attack behaviors from cyber threat intelligence due to its heterogeneous nature.Based on the Adversarial Tactics,Techniques and Common Knowledge(ATT&CK)of threat behavior description,this paper proposes a threat behavioral knowledge extraction framework that integrates Heterogeneous Text Network(HTN)and Graph Convolutional Network(GCN)to solve this issue.It leverages the hierarchical correlation relationships of attack techniques and tactics in the ATT&CK to construct a text network of heterogeneous cyber threat intelligence.With the help of the Bidirectional EncoderRepresentation fromTransformers(BERT)pretraining model to analyze the contextual semantics of cyber threat intelligence,the task of threat behavior identification is transformed into a text classification task,which automatically extracts attack behavior in CTI,then identifies the malware and advanced threat actors.The experimental results show that F1 achieve 94.86%and 92.15%for the multi-label classification tasks of tactics and techniques.Extend the experiment to verify the method’s effectiveness in identifying the malware and threat actors in APT attacks.The F1 for malware and advanced threat actors identification task reached 98.45%and 99.48%,which are better than the benchmark model in the experiment and achieve state of the art.The model can effectivelymodel threat intelligence text data and acquire knowledge and experience migration by correlating implied features with a priori knowledge to compensate for insufficient sample data and improve the classification performance and recognition ability of threat behavior in text.

Critical behavior in the itinerant ferromagnet SmMn_(2)Ge_(2)

Transition metal and rare earth intermetallics have been a fertile playground for research of various quantum states.We report detailed magnetic studies on Sm Mn_(2)Ge_(2),an anisotropic itinerant magnet with multiple magnetic phases.The critical behavior of the ferromagnetic phase transition is investigated by employing the modified Arrott plot with the Kouvel-Fisher method.The critical temperature TCis determined to be around 342.7 K with critical exponents ofβ=0.417 andγ=1.122,and the interaction function is found to be J(r)~r^(-4.68),suggesting the coexistence of long-range and shortrange magnetic interactions.Our results contribute to the understanding of complex magnetism in Sm Mn_(2)Ge_(2),which may provide fundamental guidance in future spintronic applications.

Periodical polarization reversal modulation in multiferroic MnWO_(4) under high magnetic fields

We report polarization reversal periodically controlled by the electric field in multiferroic MnWO_(4) with a pulsed field up to 52 T.The electric polarization cannot be reversed by successive opposite electric fields in low magnetic fields(<14 T)at 4.2 K,whereas polarization reversal is directly achieved by two opposite electric fields under high magnetic fields(<45 T).Interestingly,the polarization curve of rising and falling fields for H∥u(magnetic easy axis)is irreversible when the magnetic field is close to 52 T.In this case,the rising and falling polarization curves can be individually reversed by the electric field,and thus require five cycles to recover to the initial condition by the order of the applied electric fields(+E,-E,-E,+E,+E).In addition,we find that ferroelectric phaseⅣcan be tuned from parallel to antiparallel in relation to ferroelectric phase AF2 by applying a magnetic field approximated to the c axis.

The pulsed high magnetic field facility and scientific research at Wuhan National High Magnetic Field Center

Wuhan National High Magnetic Field Center(WHMFC)at Huazhong University of Science and Technology is one of the top-class research centers in the world,which can offer pulsed fields up to 90.6 T with different field waveforms for scientific research and has passed the final evaluation of the Chinese government in 2014.This paper will give a brief introduction of the facility and the development status of pulsed magnetic fields research at WHMFC.In addition,it will describe the application development of pulsed magnetic fields in both scientific and industrial research.

Incorporating topographic factors in nonlinear mixed-effects models for aboveground biomass of natural Simao pine in Yunnan,China

A total of 128 Simao pine trees （Pinus kesiya var. langbianensis） from three regions of Pu＇er City, Yunnan Province, People＇s Republic of China, were destructively sampled to obtain tree aboveground biomass （AGB）. Tree variables such as diameter at breast height and total height, and topographical factors such as altitude, aspect of slope, and degree of slope were recorded. We considered the region and site quality classes as the ran- dom-effects, and the topographic variables as the fixed- effects. We fitted a total of eight models as follows： least- squares nonlinear models （BM）, least-squares nonlinear models with the topographic factors （BMT）, nonlinear mixed-effects models with region as single random-effects （NLME-RE）, nonlinear mixed-effects models with site as single random-effects （NLME-SE）, nonlinear mixed-ef- fects models with the two-level nested region and site random-effects （TLNLME）, NLME-RE with the fixed-ef- fects of topographic factors （NLMET-RE）, NLME-SE with the fixed-effects of topographic factors （NLMET-SE）, and TLNLME with the fixed-effects of topographic factors （TLNLMET）. The eight models were compared by modelfitting and prediction statistics. The results showed： model fitting was improved by considering random-effects of region or site, or both. The models with the fixed-effects of topographic factors had better model fitting. According to AIC and BIC, the model fitting was ranked as TLNLME 〉 NLMET-RE 〉 NLME-RE.〉 NLMET-SE 〉 TLNLMET 〉 NLME-SE 〉 BMT 〉 BM. The differences among these models for model prediction were small. The model pre- diction was ranked as TLNLME 〉 NLME-RE 〉 NLME- SE 〉 NLMET-RE 〉 NLMET-SE 〉 TLNLMET 〉 BMT 〉 BM. However, all eight models had relatively high prediction precision （〉90 %）. Thus, the best model should be chosen based on the available data when using the model to predict individual tree AGB.

Simultaneous measurement of CO_2 sorption and swelling of phosphate-based ionic liquid

The development of alternative CO_2 capture solvents such as ionic liquids(ILs) and nanoparticle organic hybrid materials(NOHMs) have provided interesting options for CO_2 capture. In this study, CO_2 interactions with 1,3-dimethylimidazolium dimethylphosphate([MMIM]DMP),1-ethyl-3-methylimidazolium dimethylphosphate([EMIM]DMP) and 1-ethyl-3-methylimidazolium diethylphosphate([EMIM]DEP) that contain inorganic ester groups based on phosphate, were investigated using ATR FT-IR spectroscopy. CO_2-induced swelling, CO_2 diffusivity and CO_2 capture capacity were simultaneously measured to identify CO_2 capture mechanisms, kinetics and diffusion behaviors as a function of the alkyl chain length of the cation. Henry's law constants of CO_2 were found to be in the range of 4-11 MPa, which is in agreement with those reported in other studies.

Influence of proximity to the Qinghai-Tibet highway and railway on variations of soil heavy metal concentrations and bacterial community diversity on the Tibetan Plateau

An understanding of soil microbial communities is crucial in roadside soil environmental assessments.The 16S rRNA se quencing of a stressed microbial community in soil adjacent to the Qinghai-Tibet Highway(QTH)revealed that the accu mulation of heavy metals(over about 10 years)has affected the diversity of bacterial abundance and microbial community structure.The proximity of a sampling site to the QTH/Qinghai-Tibet Railway(QTR),which is effectively a measure of the density of human engineering,was the dominant factor influencing bacterial community diversity.The diversity of bacterial communities shows that 16S rRNA gene abundance decreased in relation to proximity to the QTH and QTR in both alpine wetland and meadow areas.The dominant phyla across all samples were Actinobacteria and Proteobacteria.The concentration of Cr and Cd in the soil were positively correlated with proximity to the QTH and QTR(MC/WC sam pling sites),and Ni,Co,and V were positively correlated with proximity to the QTH and QTR(MA/WA sampling sites).The results presented in this study provide an insight into the relationships among heavy metals and soil microbial commu nities,and have important implications for assessing and predicting the impacts of human-induced activities from the QTH and QTR in such an extreme and fragile environment.

Visualization on electrified micro-jet instability from Taylor cone in electrohydrodynamic atomization

The cone-jet in electrohydrodynamic atomization has been widely applied into numerous industrial fields owing to micro-sized drops with narrow distribution and high charge.The electrified jet emits from a single capillary sheathed with quartz tube is visualized versus operating parameters and physical properties,and breakup instabilities are also discussed.The range of operating parameters for a steady conejet broadens,as well as the minimum flow rate.Taylor cone angle decreases with an increase in flow rate,while increases as electric potential increasing.The jet breakup length decreases with an increase in flow rate and conductivity,while increases as electric potential increasing.The diffusion angle increases as flow rate increasing,while decrease as electric potential and conductivity increasing.Much clearer whipping instabilities are observed with an increase in“electro-Weber”number and conductivity.The completion in disturbance or/and suppression from axial and radial stresses,drag force dominates the variation.Meanwhile,for a large flow rate,the transition from varicose instabilities to whipping instabilities is found.The whipping instabilities are clearly observed for high conductivity due to much more free ions in liquid.For much higher conductivity,an intermittent electrified jet appears and shows an umbrella plume,and breakup length sharply shortens.

Experimental Study on the Cyclic Ampacity and Its Factor of 10 kV XLPE Cable

The load varies periodically, but the peak current of power cable is controlled by its continuous ampacity in China, resulting in the highest conductor temperature is much lower than90℃, the permitted long-term working temperature of XLPE. If the cable load is controlled by its cyclic ampacity, the cable transmission capacity could be used sufficiently. To study the 10 kV XLPE cable cyclic ampacity and its factor, a three-core cable cyclic ampacity calculation software is developed and the cyclic ampacity experiments of direct buried cable are undertaken in this paper. Experiments and research shows that the software calculation is correct and the circuit numbers and daily load factor have an important impact on the cyclic ampacity factor. The cyclic ampacity factor of 0.7 daily load factor is 1.20, which means the peak current is the 1.2 times of continuous ampacity. If the continuous ampacity is instead by the cyclic ampacity to control the cable load, the transmission capacity of the cable can be improved greatly without additional investment.

Research on the visual elements of augmented reality asse mbly processes

Background To solve the problem of visualization in augmented reality(AR),for assembly process information,we report here on our study into the composition of AR assembly process information.Methods Our work led us to classify the visual elements of assembly processes into six categories,and after looking further into visual element expression characteristics used in assembly process information in the AR environment,standard assembly process elements have been identified and visual element layout principles studied.Conclusion Typical visualization elements have been presented,using an AR-based assembly instruction system.

Magnetic properties and magnetocaloric effect in RE_(55)Co_(30)Al_(10)Si_(5)(RE=Er and Tm)amorphous ribbons

The magnetic and magnetocaloric effects(MCE)of the amorphous RE_(55)Co_(30)Al_(10)Si_(5)(RE=Er and Tm)ribbons were systematically investigated in this paper.Compounds with R=Er and Tm undergo a second-order magnetic phase transition from ferromagnetic(FM)to paramagnetic(PM)around Curie temperature T_(C)~9.3 K and 3 K,respectively.For Er_(55)Co_(30)Al_(10)Si_(5) compound,an obvious magnetic hysteresis and thermal hysteresis were observed at low field below 6 K,possibly due to spin-glass behavior.Under the field change of 0 T–5 T,the maximum values of magnetic entropy change(-△S_(M)^(max))reach as high as 15.6 J/kg·K and 15.7 J/kg·K for Er_(55)Co_(30)Al_(10)Si_(5) and Tm_(55)Co_(30)Al_(10)Si_(5) compounds,corresponding refrigerant capacity(RC)values are estimated as 303 J/kg and 189 J/kg,respectively.The large MCE makes amorphous RE_(55)Co_(30)Al_(10)Si_(5)(RE=Er and Tm)alloys become very attractive magnetic refrigeration materials in the low-temperature region.

Magnetic properties and magnetocaloric effects of Tm_(1-x)Er_(x)CuAl(x=0.25,0.5,and 0.75)compounds

We investigate the structural,magnetic,and magnetocaloric effects(MCE)of Tm_(1-x)Er_(x)CuAl(x=0.25,0.5,and 0.75)compounds.The compounds undergo a second-order phase transition originating from the ferromagnetic to paramagnetic transition around 3.2 K,5 K,and 6 K,respectively.The maximum magnetic entropy changes(-△S_(M)^(max))of Tm_(1-x)Er_(x)CuAl(x=0.25,0.5,and 0.75)are 17.1 J·kg^(-1)·K^(-1),18.1 J·kg^(-1)·K^(-1),and 17.5 J·kg^(-1)·K^(-1)under the magnetic field in the range of 0-2 T,with the corresponding refrigerant capacity(RC)values of 131 J·kg^(-1),136 J·kg^(-1),and 126 J·kg^(-1),respectively.The increase of-△S_(M)^(max)for Tm0.5Er0.5CuAl may be relevant to the change of magnetic moment distribution of Er and stress coming from element substitution.This work provides several compounds that can enrich the family of giant MCE materials in the cryogenic region.