Controllably partial removal of thiolate ligands from unsupported Au_(25) nanoclusters by rapid thermal treatments for electrochemical CO_(2)reduction

Colloidal synthesis of metal nanoclusters will inevitably lead to the blockage of catalytically active sites by organic ligands.Here,taking[Au_(25)(PET)_(18)]-(PET=2-phenylethanethiol)nanocluster as a model catalyst,this work reports a feasible procedure to achieve the controllably partial removal of thiolate ligands from unsupported[Au_(25)(PET)_(18)]-nanoclusters with the preservation of the core structure.This procedure shortens the processing duration by rapid heating and cooling on the basis of traditional annealing treatment,avoiding the reconfiguration or agglomeration of Au_(25)nanoclusters,where the degree of dethiolation can be regulated by the control of duration.This work finds that a moderate degree of dethiolation can expose the Au active sites while maintaining the suppression of the competing hydrogen evolution reaction.Consequently,the activity and selectivity towards CO formation in electrochemical CO_(2)reduction reaction of Au_(25)nanoclusters can be promoted.This work provides a new approach for the removal of thiolate ligands from atomically precise gold nanoclusters.

Imide-pillared covalent organic framework protective films as stable zinc ion-conducting interphases for dendrite-free Zn metal anodes

The notorious growth of zinc dendrite and the water-induced corrosion of zinc metal anodes(ZMAs)restrict the practical development of aqueous zinc ion batteries(AZIBs).In this work,a zinc metallized,imide-pillared covalent organic framework(ZPC)protective film has been engineered as a stable Zn^(2+)ion-conducting interphase to modulate interfacial kinetics and suppress side reactions for ZMAs.Compared to bare Zn,ZPC@Zn exhibits a higher Zn^(2+)ionic conductivity,a larger Zn^(2+)transference number,a lower electronic conductivity,a smaller desolvation activation energy and correspondingly a significant suppression of corrosion,hydrogen evolution and Zn dendrites.Impressively,the ZPC@Zn||ZPC@Zn symmetric cell obtains a cycling lifespan over 3000 h under 5 mA cm^(-2)for 1 mA h cm^(-2).The ZPC@Zn||NH_(4)V_(4)O_(10)coin-type full battery delivers a specific capacity of 195.8 mA h g^(-1)with a retention rate of78.5%at 2 A g^(-1)after 1100 cycles,and the ZPC@Zn||NH_(4)V_(4)O_(10) pouch full cell shows a retention of70.1%in reversible capacity at 3 A g^(-1)after 1100 cycles.The present incorporation of imide-linked covalent organic frameworks in the surface modification of ZMAs will offer fresh perspectives in the search for ideal protective films for the practicality of AZIBs.

A novel molybdenite depressant for efficient selective flotation separation of chalcopyrite and molybdenite

A novel small molecule depressant(M-DEP)was used to separate chalcopyrite and molybdenite via flotation.The results showed that M-DEP had an excellent selective depression on molybdenite,while had little effect on the flotation of chalcopyrite.The adsorption capacity of M-DEP on the surface of molybdenite was greater than that on chalcopyrite surface.The adsorption of M-DEP reduced the floatability of molybdenite and had less effect on the floatability of chalcopyrite,which was due to its different adsorption modes on the surface of the two minerals.Furthermore,the interaction between chalcopyrite and M-DEP was mainly chemical interaction,and almost all of the adsorbed M-DEP molecules were removed and replaced by sodium butyl xanthate(SBX).By contrast,hydrophobic interaction was the main way in which M-DEP was adsorbed on the molybdenite surface with little chemical interaction,which was less interfered by SBX addition.Therefore,M-DEP had a super selective depression on molybdenite.The study provided a novel depressant and approach for the deep separation of chalcopyrite and molybdenite via flotation.

Structure–performance relationship of Au nanoclusters in electrocatalysis:Metal core and ligand structure

Remarkable progress has characterized the field of electrocatalysis in recent decades,driven in part by an enhanced comprehension of catalyst structures and mechanisms at the nanoscale.Atomically precise metal nanoclusters,serving as exemplary models,significantly expand the range of accessible structures through diverse cores and ligands,creating an exceptional platform for the investigation of catalytic reactions.Notably,ligand‐protected Au nanoclusters(NCs)with precisely defined core numbers offer a distinct advantage in elucidating the correlation between their specific structures and the reaction mechanisms in electrocatalysis.The strategic modulation of the fine microstructures of Au NCs presents crucial opportunities for tailoring their electrocatalytic performance across various reactions.This review delves into the profound structural effects of Au NC cores and ligands in electrocatalysis,elucidating their underlying mechanisms.A detailed exploration of the fundamentals of Au NCs,considering core and ligand structures,follows.Subsequently,the interaction between the core and ligand structures of Au NCs and their impact on electrocatalytic performance in diverse reactions are examined.Concluding the discourse,challenges and personal prospects are presented to guide the rational design of efficient electrocatalysts and advance electrocatalytic reactions.

Improvement of HydrophUicity and Blood Compatibility on Polyethersulfone Membrane by Blending Sulfonated Polyethersulfone

Polyethersulfone(PES) is widely used as biomaterials due to its thermal stability,mechanical strength,and chemical inertness.Nevertheless,their blood compatibility is still not adequate for hemodialysis and blood purification.In this study,the sulfonated polyethersulfone(SPES) was synthesized through an electrophilic substitution reaction,and PES/SPES blending membranes were prepared.The characterization of the SPES was studied by FTIR.The water adsorption and water contact angle experiments show that the hydrophilicity of PES/SPES blend membrane was improved as for the sulfonate group existing in the SPES.Moreover,PES/SPES blend membrane could effectively reduce bovine serum albumin adsorption and prolong the blood coagulation time compared with the PES membrane,thereby improving blood compatibility.

Effect of low-frequency electromagnetic field on the as-cast microstructure of a new super high strength aluminum alloy by horizontal continuous casting

The super high strength aluminum alloy ingots with 100 mm in diameter were cast by the process of low-frequency electromagnetic horizontal continuous casting (LFEHC) and the effect of electromagnetic field on the as-cast microstructure was studied. Results show that microstructure of the sample prepared by the LFEHC process was greatly refined. Microstructures at the border and the center of the ingots were fine, uniform and rosette-shaped. Electromagnetic frequency plays a key role in microstructure refining. Fine and uniform microstructures can be obtained with optimal electromagnetic frequency. In this experiment, under a frequency of 30 Hz the microstructure was the finest and the most uniform.

Study on the Pigments of the Colored Cotton

The ecological characteristics and fiber structure of the colored cotton were introduced briefly. The color changing mechanisms of the pigments extracted from colored cottons and some plants were discussed with the results of different experiments, which could offer an academic reference for the color fixations of the colored cotton textile produces and promote the development of the natural colored cotton industry.

Functional characterization of the catalytic and bromodomain of FgGCN5 in development,DON production and virulence of Fusarium graminearum

FgGCN5,a GCN5 homolog in Fusarium graminearum,plays a critical role in hyphal vegetative growth,asexual and sexual reproduction,deoxynivalenol(DON)biosynthesis and plant infection.For nuclear localized GCN5,four conserved sequence motifs(I-IV)are presented in the catalytic domain and a bromodomain in the carboxy-terminus.As a lysine acetyltransferase,conserved negatively charged residues are present to neutralize the protons from lysine substrates.However,the role of conserved motifs/domains and residues in FgGCN5 are unclear.Here,we generated deletion mutant strains for each the conserved motifs/domains and a glutamate residue 130(E130)replacement mutant.Deletion of each conserved motif in the catalytic domain and replacement of E130 site resulted in manifold defects in hyphae growth,asexual and sexual development,DON biosynthesis,and plant infection.Phenotypic defects in the mutant strains were similar to deletion mutants.The deletion of the bromodomain led a significant reduction in DON production and virulence,with no effects on hyphae growth,asexual or sexual reproduction.FgGCN5 was further found to localize to the nucleus in conidia and hyphae cells.In conclusion,FgGCN5 encodes a nuclear localized acetyltransferase.The conserved motifs in the catalytic domain and E130 are essential for correct functions of the gene.The conserved bromodomain is impotant for DON production and pathogen virulence.This was the first report to identify the functions of conserved motifs/domains in FgGCN5,which will contribute to our understanding of the mechanism(s)by which FgGCN5 regulates F.graminearum.

Fine mapping of the sex locus in Salix triandra confirms a consistent sex determination mechanism in genus Salix

Salix triandra belongs to section Amygdalinae in genus Salix,which is in a different section from the willow species in which sex determination has been well studied.Studying sex determination in distantly related willow species will help to clarify whether the sexes of different willows arise through a common sex determination system.For this purpose,we generated an intraspecific full-sib F1 population for S.triandra and constructed high-density genetic linkage maps for the crossing parents using restriction site-associated DNA sequencing and following a two-way pseudo-testcross strategy.With the established maps,the sex locus was positioned in linkage group XV only in the maternal map,and no sex linkage was detected in the paternal map.Consistent with previous findings in other willow species,our study showed that chromosome XV was the incipient sex chromosome and that females were the heterogametic sex in S.triandra.Therefore,sex in this willow species is also determined through a ZW sex determination system.We further performed fine mapping in the vicinity of the sex locus with SSR markers.By comparing the physical and genetic distances for the target interval encompassing the sex determination gene confined by SSRs,severe recombination repression was revealed in the sex determination region in the female map.The recombination rate in the confined interval encompassing the sex locus was approximately eight-fold lower than the genome-wide average.This study provides critical information relevant to sex determination in S.triandra.

Enhanced electrocatalytic activity for H_2O_2 production by the oxygen reduction reaction: Rational control of the structure and composition of multi-walled carbon nanotubes

Hydrogen peroxide(H2O2)is a very useful chemical reagent,but the current industrial methods for its production suffer from serious energy consumption problems.Using high-activity and high-selectivity catalysts to electrocatalyze the oxygen reduction reaction(ORR)through a two-electron(2e^-)pathway is a very promising route to produce H2O2.In this work,we obtained partially oxidized multi-walled carbon nanotubes(MWCNTs)with controlled structure and composition by oxidation with concentrated sulfate and potassium permanganate at 40℃ for 1 h(O-CNTs-40-1).The outer layers of O-CNTs-40-1 are damaged with defects and oxygen-containing functional groups,while the inner layers are maintained intact.The optimized structure and composition of the partially oxidized MWCNTs ensure that O-CNTs-40-1 possesses both a sufficient number of catalytic sites and good conductivity.The results of rotating ring disk electrode measurements reveal that,among all oxidized MWCNTs,O-CNTs-40-1 shows the greatest improvement in hydrogen peroxide selectivity(from ~ 30% to ~ 50%)and electron transfer number(from ~ 3.4 to ~ 3.0)compared to those of the raw MWCNTs.The results of electrochemical impedance spectroscopy measurements indicate that both the charge-transfer and intrinsic resistances of O-CNTs-40-1 are lower than those of the raw MWCNTs and of the other oxidized MWCNTs.Finally,direct tests of the H2O2 production confirm the greatly improved catalytic activity of O-CNTs-40-1 relative to that of the raw MWCNTs.

Analysis and Verification on the Chain-like Model with Normal Distribution of Magnetorheological Elastomer

Magnetorheological elastomer （MRE） is a new kind of smart materials, the rheological properties can be controlled rapidly by the external magnetic field. It is mainly composed of rubber and micron-sized ferromagnetic particles, which forms a chain-like structure. Therefore its mechanical, electric, and magnetic properties can be changed by the applied magnetic field, which is called as the magneto-induced effect. But this effect is not remarkable enough currently for the engineering application. So it is important for material preparation to optimize parameters to enhance the magneto-induced effect. In this work, based on chain-like model, some factors influencing the magneto-induced effect of MRE were analyzed theoretically by using dipole method with the normal distribution of chain＇s angle introduced. The factors included the oblique angle of particles chains, magnetic field intensity, and shear strain, etc. Some experiments were also carried out.

The Web Application Test Based on Page Coverage Criteria

Software testing coverage criteria play an important role in the whole testing process.The current coverage criteria for web applications are based on program or URL.They are not suitable for black-box test or intuitional to use.This paper defines a kind of test criteria based on page coverage sequences only navigated by web application,including Page_Single,Page_Post,Page_Pre,Page_Seq2,Page_SeqK.The test criteria based on page coverage sequences made by interactions between web application and browser are being under consideration after that.In order to avoid ambiguity of natural language,these coverage criteria are depicted using Z formal language.The empirical result shows that the criteria complement traditional coverage and fault detection capability criteria.

Template-free synthesis of Co_(3)O_(4)microtubes for enhanced oxygen evolution reaction

To fully exploit the superiority of tubular structures,in this study,we systematically explore the optimal preparation conditions for Ni/Co_(3)O_(4),including cation species and content,additive species and content,and anion species.Our results reveal that the formation of an initial cobalt nickel acetate hydroxide prism is the key factor and directly affects the final microtubular structure.Moreover,P is subsequently doped into the Ni/Co_(3)O_(4)lattice to increase the M^(3+)/M^(2+)molar ratio(M=Co and Ni),promote reaction kinetics,and optimize electronic structure.Consequently,the oxygen evolution reaction performance of P-doped tubular Ni/Co_(3)O_(4)is significantly higher than that of undoped Ni/Co_(3)O_(4)and the state-of-the-art RuO_(2)electrocatalyst.

Comparison between the preparation,structure and mechanical properties of long fiber reinforced thermoplastics and short fiber reinforced thermoplastic

This article summarizes the comparison between the preparation, structure and mechanical properties of long fiber reinforced thermoplastics （LFT） and short fiber reinforced thermoplastics （SFT）. Both of the experiment and theory results showed that the mechanical properties of long glass fiber reinforced thermoplastics pellets （LGFRT） have been enhanced better than that of short glass fiber reinforced thermoplastics pellets （SGFRT） manufactured by molding procession. After regulation of the relative humidity by 50 % , the mechanical properties of 30 % （ weight percent） short glass fiber content in SFT （ SFT-PA6-SGF30 ） are similar to that of 40 % long glass fiber content in LFT. Howev- er, the density of the latter is about 17 % lower than that of the former. Thus, the corresponding weight of products is reduced by 13 % ;output rate is increased by 21% , and the cost is therefore significantly lowered. And it has the fol- lowing advantages： impact strength is increased by 87 % ; the proportion is reduced by 20 % ; molding cycle is short- ened by 10 % ;materials cost is saved by 20 % -30 % and the final total cost is saved by 30 % -40 %. So LFT （LFT-PP-LGF40） can replace SFT （SFT-PA6-SGF30） with the similar basic mechanical properties under normal tem- perature or 160 ℃ lower.

Effect of pulsed electromagnetic frequency on the microstructure, wear and solid erosion resistance of CrAlN coatings deposited by arc ion plating

In this work,the chromium aluminum nitride(CrAlN)coatings were prepared on TC11 titanium alloy by composite magnetic field cathodic arc ion plating with controllable pulse electromagnetic combined with permanent magnet.The effects of electromagnetic frequency on the morphology,microstructure,nano-hardness and elastic modulus of the coatings were investigated by scanning electron microscope(SEM),X-ray diffraction(XRD)and nano-indenter.This paper has mainly studied the influence of CrAlN coatings which are prepared at various electromagnetic frequencies on the wear and erosion resistance through a series of wear and solid particle erosion experiments.It was found that the deposition rate of CrAlN coatings increases with the increase of electromagnetic frequency.And CrAlN coatings all preferentially grew along the(111)crystal plane.At 16.7 Hz,with the increase of pulsed electromagnetic frequency,the hardness is the highest(23.6 GPa)and the adhesion is the highest(41.5 N).In addition,the coating deposition exhibited the best wear and solid erosion resistance at 16.7 Hz and 33.3 Hz,the friction coefficient is about 0.35,and the erosion rate is about 0.2μm/g at 30°and less than 1μm/g at 90°,respectively.These results indicate that the CrAlN coating formed at an appropriate pulsed electromagnetic frequency can achieve excellent mechanical properties,wear and solid erosion resistance.

The Application of Organica Ecological Technology in Residential Sewage Treatment

Water is the basis in ecological residential area. It is very important to recycle the water resource in the designing and planning of the ecological residential quarter due to the critical way to realize the wastewater resource utilization. In this paper, a new technology of wastewater treatment is introduced, which is ORGANICA ecotechnology. We integrate the traditional wastewater treatment technology and modern ecological engineering technology together and apply the integrated technology in the treatment of domestic sewage. The treated water can be reused for landscape and greening, which can beautify the residential area and recycle wastewater.

INVESTIGATION OF THE INTERACTIONS BETWEEN WATER AND MODIFIED SILICA GEL BY IGC AND TPD

In this work, the thermodynamic parameters for the adsorption of water vapor on untreated silica gel and silica gel treated with hygroscopic salts and silane coupling agent were determined by lnverse Gas Chromatography （IGC） in the infinite dilution region. The desorption activation energies of the water vapor on virgin and modified silica gels were estimated by using the Temperature Programmed Desorption （TPD） technique. The interactions between the water and the virgin and modified silica gels were discussed. Results showed that the thermodynamic parameters and desorption activation energy of water vapour on the silica gels increase with decreasing pore size and increasing the surface hydrophilic properties. The desorption activation energy of virgin and modified silica gels was found to increase with increasing the thermodynamic parameters. The larger the adsorption parameters and the desorption activation energy were, the interactions between water and virgin and modified silica gels were.

Characterization of the Causal Organism of Soft Rot of Tomatoes and Other Vegetables and Evaluation of Its Most Aggressive Isolates

To isolate the causal organism of soft rot of vegetables, diseased samples of potato, tomato, carrot, chilies, and bell pepper, were analyzed in the lab, using nutrient agar (NA) and/or the enrichment host (Bell pepper) technique. Successful isolations were purified by sub-culturing, identified as Erwinia carotovora subsp. carotovora through biochemical tests and their pathogenicity was confirmed through inoculation on green tomato fruits. The isolates were tested for their aggressiveness to find out the most aggressive one in term of producing maximum soft rot on tomatoes. CRD (completely randomized design), with four replication was used and data were analyzed using LSD (least significant test) test. Among the five isolates evaluated for aggressiveness on tomato fruits, chili isolate was found to be the most aggressive followed by tomato and potato isolates producing 22.3 mm, 7.9 mm, and 7.8 mm diameter soft rot lesions, respectively.

Effects of the sputtering power on the crystalline structure and optical properties of the silver oxide films deposited using direct-current reactive magnetron sputtering

This paper reports that a series of silver oxide （AgzO） films are deposited on glass substrates by direct-current reactive magnetron sputtering at a substrate temperature of 250 ℃ and an oxygen flux ratio of 15：18 by modifying the sputtering power （SP）. The AgxO films deposited apparently show a structural evolution from cubic biphased （AgO ＋ Ag20） to cubic single-phased （Ag20）, and to biphased （Ag20 ＋ AgO） structure. Notably, the cubic single-phased Ag20 fihn is deposited at the SP = 105 W and an AgO phase with （220） orientation discerned in the Ag^O films deposited using the SP 〉 105 W. The transmissivity and refiectivity of the AgxO films in transparent region decrease with the increase the SP, whereas the absorptivity inversely increases with the increase of the SP. These results may be due to the structural evolution and the increasing film thickness. A redshift of the films＇ absorption edges determined in terms of Tauc formula clearly occurs from 3.1 eV to 2.73 eV with the increase of the SP.

Grain dehydration rate is related to post-silking thermal time and ear characters in different maize hybrids

Mechanized grain harvest of maize becomes increasingly important with growing land plot size in Northeast China. Grain moisture is an important factor affecting the performance of mechanized grain harvest. However, it remains unclear what influences grain dehydration rate. In this study, maize grain dehydrating process was investigated in a two-year field experiment with five hybrids under two planting densities in 2017 and 2018. It was found that damaged-grain ratio was the main factor affecting mechanized harvest quality, and this ratio was positively correlated with grain moisture content at harvest(R^(2)=0.6372, P<0.01). To fulfill the national standard of <5% damaged-grain ratio for mechanized grain harvest, the optimal maize grain moisture content was 22.3%. From silking to physiological maturity, grain dehydrating process was mostly dependent on the thermal time(growing degree days, GDDs)(r=-0.9412, P<0.01). The average grain moisture content at physiological maturity was 29.4%. Thereafter, the linear relationship between GDDs and grain moisture still existed, but the correlation coefficient became smaller(r=-0.8267, P<0.01). At this stage, grain dehydrating process was greatly affected by genotypes. Grain dehydrated faster when a hybrid has a smaller husk area(r=0.6591, P<0.05), larger ear angle(r=-0.7582, P<0.05), longer ear peduncle(r=-0.9356, P<0.01) and finer ear(r=0.9369, P<0.01). These parameters can be used for breeders and farmers to select hybrids suitable for mechanized grain harvest.