The preparation process of sodium molybdate has the disadvantages of high energy consumption,low thermal efficiency,and high raw material requirement of molybdenum trioxide,in order to realize the green and efficient ...The preparation process of sodium molybdate has the disadvantages of high energy consumption,low thermal efficiency,and high raw material requirement of molybdenum trioxide,in order to realize the green and efficient development of molybdenum concentrate resources,this paper proposes a new process for efficient recovery of molybdenum from molybdenum concentrate and preparation of sodium molybdate by microwave-enhanced roasting and alkali leaching.Thermodynamic analysis indicated the feasibility of oxidation roasting of molybdenum concentrate.The effects of roasting temperature,holding time,and power-to-mass ratio on the oxidation product and leaching product sodium molybdate (Na_(2)MoO_(4)·2H_(2)O) were investigated.Under the optimal process conditions:roasting temperature of 700℃,holding time of 110 min,and power-to-mass ratio of 110 W/g,the molybdenum state of existence was converted from MoS_(2) to Mo O3.The process of preparing sodium molybdate by alkali leaching of molybdenum calcine was investigated,the optimal leaching conditions include a solution concentration of 2.5 mol/L,a liquid-to-solid ratio of 2 mL/g,a leaching temperature of 60℃,and leaching solution termination at pH 8.The optimum conditions result in a leaching rate of sodium molybdate of 96.24%.Meanwhile,the content of sodium molybdate reaches 94.08wt%after leaching and removing impurities.Iron and aluminum impurities can be effectively separated by adjusting the pH of the leaching solution with sodium carbonate solution.This research avoids the shortcomings of the traditional process and utilizes the advantages of microwave metallurgy to prepare high-quality sodium molybdate,which provides a new idea for the highvalue utilization of molybdenum concentrate.展开更多
Compared to conventional emulsions, gel-emulsions have a higher internal phase volume fraction, unique structures and properties, higher viscosity, and tunable internal structures. These advantages make them widely ap...Compared to conventional emulsions, gel-emulsions have a higher internal phase volume fraction, unique structures and properties, higher viscosity, and tunable internal structures. These advantages make them widely applicable in the cosmetics industry, food industry, aerospace, and biomedicine, with significant potential in the development of new materials and high-performance products. The factors affecting the stability of gel-emulsions, as well as the types of stabilizers required for their preparation (including solid particles, surfactants, and small molecule gelators), and the corresponding preparation methods (including the one-step method, two-step method, and phase inversion method) are reviewed in this article. The applications of gel-emulsions in porous materials, food, cosmetics, and stimuli-responsive materials are introduced, and future research directions are also discussed.展开更多
Heavy metal (loid)(HM) accumulation in the soil and the HM spatiotemporal distribution have important implication for soil pollution prevention and remediation. The present study investigated the concentrations and sp...Heavy metal (loid)(HM) accumulation in the soil and the HM spatiotemporal distribution have important implication for soil pollution prevention and remediation. The present study investigated the concentrations and spatiotemporal distributions of lead (Pb), mercury (Hg), cadmium (Cd), chromium (Cr) and arsenic (As) in the topsoil of a coal chemical plant in Ningxia Aulonomous region (Ningxia), China. Topsoil samples (/?= 153) were obtained using the checkerboard method, and the HM concentrations were determined. The soil residual rates of the five HMs were measured with leaching experinients and were applied in a soil environmental capacity model to predict the quarHitiHive variation of the HM concentrations. The predicted results were employed to estimate the HM spatiotemporal distribution within 2() years with the Kriging technique. The number of sampling sites, where all five HM concentratio ns exceed their corresponding background values in Ningxia, would be increased from 0 to 90% within 1() years of the plant operation. In addition, Pb and Cd were distributed along the traffic routes. Mercury and As were distributed near fuel gas emission vents. Chromium was mainly accumulated in slag dumps. The study may provide the theoretical and practical foun d at ion for future HM pollution control in coal chemical plants.展开更多
DAPTMGY(DTY)is an oligopeptide derived from marine microalgae with proven potential to combat oxidative stress in previous research.The composition,ordering,and active sites of amino acids play a key role in activity ...DAPTMGY(DTY)is an oligopeptide derived from marine microalgae with proven potential to combat oxidative stress in previous research.The composition,ordering,and active sites of amino acids play a key role in activity studies and are also the research trends in recent years.As an oligopeptide with a molecular weight of less than 1000 Da,DTY is of great significance to explore the active site and structure-activity relationship.This study used quantum mechanics to optimize DTY’s structure and predict the active site through molecular orbits,energy,and charge.In addition,an LPS-treated HUVEC cell was established as an oxidative-stress model.DTY could reduce mitochondrial oxidative stress and inhibit ROS production by enhancing the antioxidant enzymes SOD,GPX,and HO-1.Moreover,it was confirmed to inhibit inflammation and apoptosis through the NF-κB and MAPK signaling pathways.Lastly,the correlation of the oligopeptide DTY’s active site and antioxidative-stress activity was verified by molecular docking,showing that hydrogen bonding is the main force,which was also the main factor for antioxidant activity.展开更多
Eutrophication in coastal waters has been increasing remarkably,severely impacting the water quality in mariculture bays.In this study,we conducted multiple isotopic measurements on suspended particulate nitrogen(δ^(...Eutrophication in coastal waters has been increasing remarkably,severely impacting the water quality in mariculture bays.In this study,we conducted multiple isotopic measurements on suspended particulate nitrogen(δ^(15)N-PN) and dissolved nitrate(δ^(15)N-NO_(3)^(-)and δ^(18)O-NO_(3)^(-)) in Zhanjiang Bay,a typical mariculture bay with a high level of eutrophication in South China,to investigate the changes in nitrogen sources and their cycling between the rainy and dry seasons.During the rainy season,the study found no significant relation between δ^(15)NPN and δ^(15)N-NO_(3)^(-)due to the impact of heavy rainfall and terrestrial erosion.In the upper bay,a slight nitrate loss and slightly higher δ_(15)N-NO_(3)^(-)and δ^(18)O-NO_(3)^(-)values were observed,attributed to intense physical sedimentwater interactions.Despite some fluctuations,nitrate concentrations in the lower bay mainly aligned with the theoretical mixing line during the rainy season,suggesting that nitrate was primarily influenced by terrestrial erosion and that nitrate isotopes resembled the source.Consequently,the isotopic values of nitrate can be used for source apportionment in the rainy season.The results indicated that soil nitrogen(36%) and manure and sewage(33%) were the predominant nitrogen sources contributing to nitrogen loads during this period.In contrast,the dry season saw a deficient ammonium concentration(<0.2 μmol/L) in the bay,due to nearly complete consumption by phytoplankton during the red tide period.Additionally,the significant loss of nitrate and simultaneous increase in the stable isotopes of dissolved and particulate nitrogen suggest a strong coupling of assimilation and mineralization during the dry season.More active biogeochemical processes during the dry season may be related to decreased runoff and increased water retention time.Overall,our study illustrated the major seasonal nitrogen sources and their dynamics in Zhanjiang B ay,providing valuable insights for formulating effective policies to mitigate eutrophication in mariculture bays.展开更多
Many migratory birds exhibit interannual consistency in migration schedules,routes and stopover sites.Detecting the interannual consistency in spatiotemporal characteristics helps understand the maintenance of migrati...Many migratory birds exhibit interannual consistency in migration schedules,routes and stopover sites.Detecting the interannual consistency in spatiotemporal characteristics helps understand the maintenance of migration and enables the implementation of targeted conservation measures.We tracked the migration of Whimbrel(Numenius phaeopus)in the East Asian-Australasian Flyway and collected spatiotemporal data from individuals that were tracked for at least two years.Wilcoxon non-parametric tests were used to compare the interannual variations in the dates of departure from and arrival at breeding/nonbreeding sites,and the inter-annual variation in the longitudes when the same individual across the same latitudes.Whimbrels exhibited a high degree of consistency in the use of breeding,nonbreeding,and stopover sites between years.The variation of arrival dates at nonbreeding sites was significantly larger than that of the departure dates from nonbreeding and breeding sites.Repeatedly used stopover sites by the same individuals in multiple years were concentrated in the Yellow Sea coast during northward migration,but were more widespread during southward migration.The stopover duration at repeatedly used sites was significantly longer than that at sites used only once.When flying across the Yellow Sea,Whimbrels breeding in Sakha(Yakutia)exhibited the highest consistency in migration routes in both autumn and spring.Moreover,the consistency in migration routes of Yakutia breeding birds was generally higher than that of birds breeding in Chukotka.Our results suggest that the northward migration schedule of the Whimbrels is mainly controlled by endogenous factors,while the southward migration schedule is less affected by endogenous factors.The repeated use of stopover sites in the Yellow Sea coast suggests this region is important for the migration of Whimbrel,and thus has high conservation value.展开更多
Novel porous Mn2O3 with good crystallinity was synthesized via hard-template method. Hb-Mn2O3 na-nocomposite was prepared and used for biosensor construction. The Hb-Mn2O3-Nafion modified electrode shows fast direct e...Novel porous Mn2O3 with good crystallinity was synthesized via hard-template method. Hb-Mn2O3 na-nocomposite was prepared and used for biosensor construction. The Hb-Mn2O3-Nafion modified electrode shows fast direct electron transfer and displays good electrocatalytic response to the reduction of H2O2. The response time is less than 5 s, the sensitivity is as high as 493 μA·L·mmol-1·cm-2 in a linear range of 1-100 μmol/L, and the detection limit is 0.16 μmol/L. This modified electrode also shows good stability and reproducibility. This indicates that the porous Mn2O3 provides a good matrix for enzyme immobilization and biosensor construction.展开更多
The microbial fuel cell, which can convert the chemical energy of organic matter into electricity via the catalytic action of microorganisms, is a novel environmentally friendly technology for wastewater treatment and...The microbial fuel cell, which can convert the chemical energy of organic matter into electricity via the catalytic action of microorganisms, is a novel environmentally friendly technology for wastewater treatment and energy generation. The electrical energy generated by the microbial fuel cell can be used as an alternative to a traditional external power source required to extract copper via electrolytic treatment. A dual-chamber microbial fuel cell(DMFC) for the treatment of copper slag sulfuric acid leach liquor was constructed. The electrogenesis performance of the DMFC and its ability to extract copper from the copper slag leachate were investigated. The results demonstrated that the maximum voltage was 540 mV when the DMFC achieved steady-state operation. The removal rate of copper ions was greater than 80.0%, and the maximum value was 92.1%. Moreover, X-ray diffraction and scanning electron microscopy were used to characterize the cathodal products. The results showed that the product deposited onto the cathode was copper and that its morphology was similar to that of the electrolytic copper powder. The DMFC can generate electricity and recover copper from copper slag simultaneously.展开更多
In order to study the mechanism of selective catalytic reduction of activated coke to remove NO in low-temperature flue gas and provide some theoretical basis for the development of related technologies.The pore sized...In order to study the mechanism of selective catalytic reduction of activated coke to remove NO in low-temperature flue gas and provide some theoretical basis for the development of related technologies.The pore sizedistribution and BET specific surface area of AC were obtain by data analyzing of N2 adsorption/desorption isotherm at -196 ℃ and carbon matrix and surface chemistry of virgin activated coke samples were characterized by acid-base titration and XPS.The process of selective catalytic reduction of activated coke (AC) samples with NH3 as reducing agent was studied in a fixed bed reactor at 150 ℃.The result shows that pore size distribution or BET specific surface of activated cokes have not correlation with denitrification activity for SCR.The NO reduction activities of the activated cokes are apparent to increase with their surface oxygen element content and total amount of acidic sites.Obviously there is good linear relationship between the NH3 adsorption capacity and activity for SCR with linear correlation coefficient 0.943.It has been presented that adsorption of NH3 on acidic functional groups in the edge of large polycyclic aromatic ring of activated coke is key rate controlling step in the SCR heterogeneous catalytic reaction.展开更多
Quantitative information on mass concentrations and other characteristics, such as spatial distribution, seasonal variation, indoor/outdoor (I/O) ratio, correlations and sources, of indoor and outdoor PM2.5 and elem...Quantitative information on mass concentrations and other characteristics, such as spatial distribution, seasonal variation, indoor/outdoor (I/O) ratio, correlations and sources, of indoor and outdoor PM2.5 and elemental components in Guangzhou City were provided. Mass concentration of PM2.5 and elemental components were determined by standard weight method and proton-induced X-ray emission (PIXE) method. 18 elements were detected, the results showed positive results. Average indoor and outdoor PM2.5 concentrations in nine sites were in the range of 67.7-74.5μg/m^3 for summer period, and 109.9-123.7 μg/m^3 for winter period, respectively. The sum of 18 elements average concentrations were 5362.6-5533.4 ng/m^3 for summer period, and 8416.8-8900.6 ng/m^3 for winter period, respectively. Average concentrations of PM2.5 and element components showed obvious spatial characteristic, that the concentrations in roadside area and in industrial plant area were higher than those in generic urban area. An obvious seasonal variation characteristic was found for PM2.5 and elemental components, that the concentrations in winter were higher than that in summer. The I/O ratio of PM2.5 and some elemental components presented larger than 1 sometimes. According to indoor/outdoor correlation of PM2.5 and element concentrations, it was found that there were often good relationships between indoor and outdoor concentrations. Enrichment factors were calculated to evaluate anthropogenic versus natural elements sources.展开更多
Polymer bonded explosive(PBX)formulations were successfully prepared in the laboratory scale containing 1,1-diamino-2,2-dinitroethene(FOX-7)and hexogen(RDX)as brisant high explosives and different binder types of poly...Polymer bonded explosive(PBX)formulations were successfully prepared in the laboratory scale containing 1,1-diamino-2,2-dinitroethene(FOX-7)and hexogen(RDX)as brisant high explosives and different binder types of polyurethane(PU)based on glycidyl azide polymer(GAP) and hydroxyl-terminated polybutadiene(HTPB) as an energetic and inert polymeric binder respectively.Casting technique was used for the preparation of different PBX formulations based on FOX-7/RDX and PU(GAP/HTPB)with 14% binder.The sensitivity to different initial impulses and performance characteristics of the explosive and lethal zone of the tested controlled fragmentation warhead by the fragmentation warhead assessment test(arena test)were studied,in which the arena test was carried out with a controlled fragmentation warhead made from Ck45 steel,with dimensions(100 mm length,30 mm outer diameter and 3 mm thickness).Results show that PBXGF4 has lower sensitivity to impact and heat than those of PBXGR4 by 188.4% and 3.2% respectively.Its friction sensitivity is the same as that of PBXGR4.It has better performance,in which detonation velocity increases by 2.1% and brisance increases by 0.5% when compared with those of PBXGR4.It was concluded that PBXGF4 which based on FOX-7 bonded with PU/GAP matrix has good characteristics as PBX,specially in the sensitivity to impact and can be applied for replacing PBXs based on RDX in the advanced PBXs for low sensitive fragmentation warheads.展开更多
Cylindrical nickel metal hydride (Ni-MH) battery with high specific volume capacity was prepared by using the oxyhydroxide Ni(OH)2 and AB5 type hydrogen storage alloy and adjusting the designing parameters of posi...Cylindrical nickel metal hydride (Ni-MH) battery with high specific volume capacity was prepared by using the oxyhydroxide Ni(OH)2 and AB5 type hydrogen storage alloy and adjusting the designing parameters of positive and negative electrodes. The oxyhydroxide Ni(OH)2 was synthesized by oxidizing spherical β-Ni(OH)2 with chemical method. The X-ray diffraction (XRD) patterns and the Fourier transform infrared (PT-IR) spectra indicated that 7-NiOOH was formed on the oxyhydroxide Ni(OH)2 powders, and some H2O molecules were inserted into their crystal lattice spacing. The battery capacity could not be improved when the oxyhydroxide Ni(OH)2 sample was directly used as the positive active materials. However, based on the conductance and residual capacity of the oxyhydroxide Ni(OH)2 powders, AA size Ni-MH battery with 2560 mA.h capacity and 407 W·h·L^-1 specific volume energy at 0.2C was obtained by using the commercial spherical β-Ni(OH)2 and AB5-type hydrogen-storage alloy powders as the active materials when 10% mass amount of the oxyhydroxide Ni(OH)2 with 2.50 valence was added to the positive active materials and subsequently the battery designing parameters were adjusted as well. The as-prepared battery showed 70% initial capacity after 80 cycles at 0.5C. The possibility for adjusting the capacity ratio of positive and negative electrodes from 1 : 1.35 to 1 : 1.22 was demonstrated preliminarily. It is considered the as-prepared battery can meet the requirement of some special portable electrical instruments.展开更多
With the discovery of graphene,black phosphorus(BP)has been rediscovered as a two-dimensional(2 D)layered material.Since its first preparation in 2014,2 D BP has elicited immense interest,and has exhibited excellent p...With the discovery of graphene,black phosphorus(BP)has been rediscovered as a two-dimensional(2 D)layered material.Since its first preparation in 2014,2 D BP has elicited immense interest,and has exhibited excellent properties,such as distinct pleated structures in layers,adjustable direct bandgap,high carrier mobility,moderate on/off ratio,large specific surface area,and various interesting in-layer anisotropies.However,the realization of these excellent properties depends on the preparation of highquality 2 D BP sheets.Electrochemical exfoliation methods are typically performed under mild conditions,thus,these methods are convenient,controllable,and can produce high-quality 2 D BP sheets.This review summarizes research progress in BP sheets preparation through anodic,cathodic,and electrolyte exfoliation in recent years.Different exfoliating methods affect the quality of 2 D BP sheets.Moreover,possible exfoliating mechanisms and the potential applications of different exfoliating methods are summarized and discussed in detail.Lastly,the shortcomings of existing research on electrochemical exfoliation are presented,and suggestions and prospects for future research on the electrochemical exfoliation of 2 D BP are proposed.展开更多
Dandelion-like TiO2 microspheres consisting of numerous rutile single-crystalline nanorods were synthesized for the first time by a hydrothermal method. Their crystal structure, morphology and electrochemical properti...Dandelion-like TiO2 microspheres consisting of numerous rutile single-crystalline nanorods were synthesized for the first time by a hydrothermal method. Their crystal structure, morphology and electrochemical properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and galvanostatic charge and discharge tests. The results show that the synthesized TiO2 microspheres exhibit good rate and cycle performances as anode materials of lithium ion batteries. It can be found that the dandelion-like structure provides a larger specific surface area and the single-crystalline nanorod provides a stable structure and fast pathways for electron and lithium ion transport, which contribute to the rate and cycle performances of the battery.展开更多
Flotation is often employed to separate valuable natural minerals and gangue minerals.However,few studies have been conducted on artificial mineral flotation.Anosovite,the primary mineral in titanium slag,is a typical...Flotation is often employed to separate valuable natural minerals and gangue minerals.However,few studies have been conducted on artificial mineral flotation.Anosovite,the primary mineral in titanium slag,is a typical artificial mineral that can be enriched by flotation.In the present work,flotation behavior and adsorption mechanism of anosovite in salicylhydroxamic acid(SHA)solution were studied.The influence of pH and SHA dosage on anosovite flotability was investigated.Micro-flotation test results show that a pH range of 7–8.5 is available for SHA to collect anosovite.A maximum recovery of 93.26%can be obtained with SHA dosage of only 4×10.5 mol/L.In addition,TOC,zeta potential,FTIR,SEM-EDS,and XPS analyses were used to study the adsorption mechanism.Results demonstrated that SHA adsorption is governed by chemisorption.XPS studies further suggested that chemical adsorption occurred at the Ti sites on the anosovite surface.展开更多
Membrane fouling is often considered as a hindrance for the application of microfiltration/ultrafiltration(MF/UF) for drinking water production. A novel process of photocatalytic membrane reactor/dynamic membrane(PMR/...Membrane fouling is often considered as a hindrance for the application of microfiltration/ultrafiltration(MF/UF) for drinking water production. A novel process of photocatalytic membrane reactor/dynamic membrane(PMR/DM), operating in a continuous mode under sub-critical flux, was proposed for the mitigation of membrane fouling caused by humic acids(HAs) in water. The mechanism of membrane fouling alleviation with synergistic photocatalytic oxidation and dynamic layer isolating effect was comprehensively investigated from the characterization of foulant evolution responsible for the reversible and irreversible fouling. The results showed that the PMR/DM utilized photocatalytic oxidation to enhance the porosity and hydrophilicity of the fouling layer by converting the high molecular weight(MW) and hydrophobic HA molecules with carboxylic functional groups and aromatic structures into low-MW hydrophilic or transphilic fractions, including tryptophan-like or fulvic-like substances. The fouling layer formed in the PMR/DM by combination of photocatalytic oxidation and DM running at a sub-critical flux of 100 L·h^-1·m^-2, was more hydrophilic and more porous, resulting in the lowest trans-membrane pressure(TMP) growth rates, as compared to the processes of ceramic membrane(CM), DM and PMR/CM.Meanwhile, the dynamic layer prevented the foulants, particularly the high-MW hydrophobic fractions,from contacting the primary membrane, which enabled the membrane permeability to be restored easily.展开更多
Two dinuclear compounds [Ln2(acetate)6(H2O)4]-4H2O (Ln=Tb(1), Sm(2)) were obtained by the hydrothermal reaction of Ln2O3 with malonic acid at 150 ℃. Both compounds were characterized by elemental analyses, ...Two dinuclear compounds [Ln2(acetate)6(H2O)4]-4H2O (Ln=Tb(1), Sm(2)) were obtained by the hydrothermal reaction of Ln2O3 with malonic acid at 150 ℃. Both compounds were characterized by elemental analyses, infrared spectra, and single crystal X-ray diffraction. The results showed that complexes 1 and 2 were isomorphous and crystallize in triclinic space group P 1. The coordination geometry around Ln(Ⅲ) ions in the complexes 1 and 2 was a distorted tricapped trigonal prism with a nine coordination. In the crystal, the molecular organization was further stabilized by well-defined weak hydrogen bonding interactions between the neutral dinuclear molecular units that led to the formation of a three-dimensional network. The fluorescence properties of the two complexes 1 and 2 in organic solvents were also studied. The results show that the ligand acetate favored energy transfer to the emitting energy level of Tb(Ⅲ) in complex 1. Some factors that influence the fluorescent intensity were also discussed in the article.展开更多
Organic–inorganic perovskites solar cells(PSCs)have attracted great attention due to their rapid progress in power conversion efficiency(PCE).However,there is still an enormous challenge to achieve both high efficien...Organic–inorganic perovskites solar cells(PSCs)have attracted great attention due to their rapid progress in power conversion efficiency(PCE).However,there is still an enormous challenge to achieve both high efficiency and stability devices as the decomposition of perovskite materials under humid and light conditions.Herein,we demonstrate that high efficiency and stability of PSCs can be obtained by the reaction of three-dimensional(3D)perovskite with 1,4-butanediamine iodide(BEAI2)vapor.The incorporation of BEAI2 intensively promotes the crystallization of perovskite film with large grain size(~500 nm).Further characterization reveals that the post-treatment perovskite film delivered low interface trap density with long carrier lifetime(>200 ns),long carrier diffusion length(>600 nm)and large carrier mobility(>1.5 cm^2 V-1S-1).Solar cells employing such post-treatment films demonstrated 19.58%PCE without hysteresis.Moreover,the post-treatment devices can retain over 90%original efficiencies stored under ambient atmospheric conditions and exhibit better stability under 85℃and continuous illumination as a two-dimensional(2D)perovskite thin layer is formed on the surface/or at the grain boundaries of 3D perovskite.This study offers an effective way to obtain PSCs with high efficiency and stability.展开更多
Superconducting vanadium nitride (VN) is successfully synthesized by a solid-state reaction of vanadium pentox- ide, sodium amide and sulfur in an autoclave at a relatively low temperature (240-400℃). The obtaine...Superconducting vanadium nitride (VN) is successfully synthesized by a solid-state reaction of vanadium pentox- ide, sodium amide and sulfur in an autoclave at a relatively low temperature (240-400℃). The obtained samples are characterized by x-ray diffraction, x-ray photoelectron spectroscopy and transmission electron microscopy. The result of the magnetization of the obtained VN product as a function of temperature indicates that the onset superconducting transition temperature is about 8.4K. Furthermore, the possible reaction mechanism is also discussed.展开更多
Two new coordination polymers(CPs) based on two new tetrazole-based ligands, namely, [Cu(TPP)]n(HTTP = 4-(3-(2 H-tetrazol-5-yl)phenyl)pyridine, 1) and {[Cd_2(TBCA)_2(H_2O)_2]·-H_2O}n(H_2TBCA = 3?-(2 H-tetrazol-5-...Two new coordination polymers(CPs) based on two new tetrazole-based ligands, namely, [Cu(TPP)]n(HTTP = 4-(3-(2 H-tetrazol-5-yl)phenyl)pyridine, 1) and {[Cd_2(TBCA)_2(H_2O)_2]·-H_2O}n(H_2TBCA = 3?-(2 H-tetrazol-5-yl)biphenyl-4-carboxylic acid, 2), were synthesized via solvothermal reactions. Single-crystal X-ray diffraction analysis reveals that compound 1 exhibits a(3,6)-connected rtl network topology based on binuclear secondary building units(SBUs). Compound 2 presents a 2D framework composed of 1D SUBs formed by both carboxyl and tetrazole groups. The 2D network is linked into a 3D framework via various hydrogen bonds. They represent two examples of CPs construct from rigid 5-substitued tetrazole-based ligands with relatively longer spacer. The thermal stabilities and luminescent properties of compounds 1 and 2 were also explored.展开更多
基金financially supported by the National Natural Science Foundation of China (No.51964046)。
文摘The preparation process of sodium molybdate has the disadvantages of high energy consumption,low thermal efficiency,and high raw material requirement of molybdenum trioxide,in order to realize the green and efficient development of molybdenum concentrate resources,this paper proposes a new process for efficient recovery of molybdenum from molybdenum concentrate and preparation of sodium molybdate by microwave-enhanced roasting and alkali leaching.Thermodynamic analysis indicated the feasibility of oxidation roasting of molybdenum concentrate.The effects of roasting temperature,holding time,and power-to-mass ratio on the oxidation product and leaching product sodium molybdate (Na_(2)MoO_(4)·2H_(2)O) were investigated.Under the optimal process conditions:roasting temperature of 700℃,holding time of 110 min,and power-to-mass ratio of 110 W/g,the molybdenum state of existence was converted from MoS_(2) to Mo O3.The process of preparing sodium molybdate by alkali leaching of molybdenum calcine was investigated,the optimal leaching conditions include a solution concentration of 2.5 mol/L,a liquid-to-solid ratio of 2 mL/g,a leaching temperature of 60℃,and leaching solution termination at pH 8.The optimum conditions result in a leaching rate of sodium molybdate of 96.24%.Meanwhile,the content of sodium molybdate reaches 94.08wt%after leaching and removing impurities.Iron and aluminum impurities can be effectively separated by adjusting the pH of the leaching solution with sodium carbonate solution.This research avoids the shortcomings of the traditional process and utilizes the advantages of microwave metallurgy to prepare high-quality sodium molybdate,which provides a new idea for the highvalue utilization of molybdenum concentrate.
文摘Compared to conventional emulsions, gel-emulsions have a higher internal phase volume fraction, unique structures and properties, higher viscosity, and tunable internal structures. These advantages make them widely applicable in the cosmetics industry, food industry, aerospace, and biomedicine, with significant potential in the development of new materials and high-performance products. The factors affecting the stability of gel-emulsions, as well as the types of stabilizers required for their preparation (including solid particles, surfactants, and small molecule gelators), and the corresponding preparation methods (including the one-step method, two-step method, and phase inversion method) are reviewed in this article. The applications of gel-emulsions in porous materials, food, cosmetics, and stimuli-responsive materials are introduced, and future research directions are also discussed.
文摘Heavy metal (loid)(HM) accumulation in the soil and the HM spatiotemporal distribution have important implication for soil pollution prevention and remediation. The present study investigated the concentrations and spatiotemporal distributions of lead (Pb), mercury (Hg), cadmium (Cd), chromium (Cr) and arsenic (As) in the topsoil of a coal chemical plant in Ningxia Aulonomous region (Ningxia), China. Topsoil samples (/?= 153) were obtained using the checkerboard method, and the HM concentrations were determined. The soil residual rates of the five HMs were measured with leaching experinients and were applied in a soil environmental capacity model to predict the quarHitiHive variation of the HM concentrations. The predicted results were employed to estimate the HM spatiotemporal distribution within 2() years with the Kriging technique. The number of sampling sites, where all five HM concentratio ns exceed their corresponding background values in Ningxia, would be increased from 0 to 90% within 1() years of the plant operation. In addition, Pb and Cd were distributed along the traffic routes. Mercury and As were distributed near fuel gas emission vents. Chromium was mainly accumulated in slag dumps. The study may provide the theoretical and practical foun d at ion for future HM pollution control in coal chemical plants.
基金The research was funded by the 2020 Shenzhen International Scientific and Technological Cooperation R&D Project(No.GJHZ20190823111601682)the Natural Science Foundation of Guangdong Province(No.2020A 1515011075)+2 种基金It was supported by the Special Funds for the‘Cultivation of Guangdong College Students’Scientific and Technological Innovation(‘Climbing Program’Special Funds No.pdjh2022a0232)The study also was funded by the Postgraduate Education Innovation Project of Guangdong Ocean University(No.2021148)Innovative Training Program for College Students of Guangdong Ocean University(No.S202210566067)。
文摘DAPTMGY(DTY)is an oligopeptide derived from marine microalgae with proven potential to combat oxidative stress in previous research.The composition,ordering,and active sites of amino acids play a key role in activity studies and are also the research trends in recent years.As an oligopeptide with a molecular weight of less than 1000 Da,DTY is of great significance to explore the active site and structure-activity relationship.This study used quantum mechanics to optimize DTY’s structure and predict the active site through molecular orbits,energy,and charge.In addition,an LPS-treated HUVEC cell was established as an oxidative-stress model.DTY could reduce mitochondrial oxidative stress and inhibit ROS production by enhancing the antioxidant enzymes SOD,GPX,and HO-1.Moreover,it was confirmed to inhibit inflammation and apoptosis through the NF-κB and MAPK signaling pathways.Lastly,the correlation of the oligopeptide DTY’s active site and antioxidative-stress activity was verified by molecular docking,showing that hydrogen bonding is the main force,which was also the main factor for antioxidant activity.
基金The National Natural Science Foundation of China under contract Nos 42276047, 92158201 and U1901213the Entrepreneurship Project of Shantou under contract No.2021112176541391the Scientific Research Start-Up Foundation of Shantou University under contract No.NTF20006。
文摘Eutrophication in coastal waters has been increasing remarkably,severely impacting the water quality in mariculture bays.In this study,we conducted multiple isotopic measurements on suspended particulate nitrogen(δ^(15)N-PN) and dissolved nitrate(δ^(15)N-NO_(3)^(-)and δ^(18)O-NO_(3)^(-)) in Zhanjiang Bay,a typical mariculture bay with a high level of eutrophication in South China,to investigate the changes in nitrogen sources and their cycling between the rainy and dry seasons.During the rainy season,the study found no significant relation between δ^(15)NPN and δ^(15)N-NO_(3)^(-)due to the impact of heavy rainfall and terrestrial erosion.In the upper bay,a slight nitrate loss and slightly higher δ_(15)N-NO_(3)^(-)and δ^(18)O-NO_(3)^(-)values were observed,attributed to intense physical sedimentwater interactions.Despite some fluctuations,nitrate concentrations in the lower bay mainly aligned with the theoretical mixing line during the rainy season,suggesting that nitrate was primarily influenced by terrestrial erosion and that nitrate isotopes resembled the source.Consequently,the isotopic values of nitrate can be used for source apportionment in the rainy season.The results indicated that soil nitrogen(36%) and manure and sewage(33%) were the predominant nitrogen sources contributing to nitrogen loads during this period.In contrast,the dry season saw a deficient ammonium concentration(<0.2 μmol/L) in the bay,due to nearly complete consumption by phytoplankton during the red tide period.Additionally,the significant loss of nitrate and simultaneous increase in the stable isotopes of dissolved and particulate nitrogen suggest a strong coupling of assimilation and mineralization during the dry season.More active biogeochemical processes during the dry season may be related to decreased runoff and increased water retention time.Overall,our study illustrated the major seasonal nitrogen sources and their dynamics in Zhanjiang B ay,providing valuable insights for formulating effective policies to mitigate eutrophication in mariculture bays.
基金supported by the National Key Research and Development Program of China(2023YFF1304504)the National Natural Science Foundation of China(31830089 and 31772467)+1 种基金the Science and Technology Department of Shanghai(21DZ1201902)the World Wide Fund for Nature Beijing Office(10003881).
文摘Many migratory birds exhibit interannual consistency in migration schedules,routes and stopover sites.Detecting the interannual consistency in spatiotemporal characteristics helps understand the maintenance of migration and enables the implementation of targeted conservation measures.We tracked the migration of Whimbrel(Numenius phaeopus)in the East Asian-Australasian Flyway and collected spatiotemporal data from individuals that were tracked for at least two years.Wilcoxon non-parametric tests were used to compare the interannual variations in the dates of departure from and arrival at breeding/nonbreeding sites,and the inter-annual variation in the longitudes when the same individual across the same latitudes.Whimbrels exhibited a high degree of consistency in the use of breeding,nonbreeding,and stopover sites between years.The variation of arrival dates at nonbreeding sites was significantly larger than that of the departure dates from nonbreeding and breeding sites.Repeatedly used stopover sites by the same individuals in multiple years were concentrated in the Yellow Sea coast during northward migration,but were more widespread during southward migration.The stopover duration at repeatedly used sites was significantly longer than that at sites used only once.When flying across the Yellow Sea,Whimbrels breeding in Sakha(Yakutia)exhibited the highest consistency in migration routes in both autumn and spring.Moreover,the consistency in migration routes of Yakutia breeding birds was generally higher than that of birds breeding in Chukotka.Our results suggest that the northward migration schedule of the Whimbrels is mainly controlled by endogenous factors,while the southward migration schedule is less affected by endogenous factors.The repeated use of stopover sites in the Yellow Sea coast suggests this region is important for the migration of Whimbrel,and thus has high conservation value.
基金Supported by the National Basic Research Program of China(No.2011CB935700)the National Natural Science Foundation of China(No.U0734002)
文摘Novel porous Mn2O3 with good crystallinity was synthesized via hard-template method. Hb-Mn2O3 na-nocomposite was prepared and used for biosensor construction. The Hb-Mn2O3-Nafion modified electrode shows fast direct electron transfer and displays good electrocatalytic response to the reduction of H2O2. The response time is less than 5 s, the sensitivity is as high as 493 μA·L·mmol-1·cm-2 in a linear range of 1-100 μmol/L, and the detection limit is 0.16 μmol/L. This modified electrode also shows good stability and reproducibility. This indicates that the porous Mn2O3 provides a good matrix for enzyme immobilization and biosensor construction.
基金financially supported by the Jiangsu Province Natural Science Foundation of China (No. BK20131133)
文摘The microbial fuel cell, which can convert the chemical energy of organic matter into electricity via the catalytic action of microorganisms, is a novel environmentally friendly technology for wastewater treatment and energy generation. The electrical energy generated by the microbial fuel cell can be used as an alternative to a traditional external power source required to extract copper via electrolytic treatment. A dual-chamber microbial fuel cell(DMFC) for the treatment of copper slag sulfuric acid leach liquor was constructed. The electrogenesis performance of the DMFC and its ability to extract copper from the copper slag leachate were investigated. The results demonstrated that the maximum voltage was 540 mV when the DMFC achieved steady-state operation. The removal rate of copper ions was greater than 80.0%, and the maximum value was 92.1%. Moreover, X-ray diffraction and scanning electron microscopy were used to characterize the cathodal products. The results showed that the product deposited onto the cathode was copper and that its morphology was similar to that of the electrolytic copper powder. The DMFC can generate electricity and recover copper from copper slag simultaneously.
基金The authors are grateful to the National Key Research and Development Program of China(NO.2016YFC0204100).
文摘In order to study the mechanism of selective catalytic reduction of activated coke to remove NO in low-temperature flue gas and provide some theoretical basis for the development of related technologies.The pore sizedistribution and BET specific surface area of AC were obtain by data analyzing of N2 adsorption/desorption isotherm at -196 ℃ and carbon matrix and surface chemistry of virgin activated coke samples were characterized by acid-base titration and XPS.The process of selective catalytic reduction of activated coke (AC) samples with NH3 as reducing agent was studied in a fixed bed reactor at 150 ℃.The result shows that pore size distribution or BET specific surface of activated cokes have not correlation with denitrification activity for SCR.The NO reduction activities of the activated cokes are apparent to increase with their surface oxygen element content and total amount of acidic sites.Obviously there is good linear relationship between the NH3 adsorption capacity and activity for SCR with linear correlation coefficient 0.943.It has been presented that adsorption of NH3 on acidic functional groups in the edge of large polycyclic aromatic ring of activated coke is key rate controlling step in the SCR heterogeneous catalytic reaction.
基金Project supported by the Foundation of Research Grants Council of Hong Kong (No. PolyU 5145/03E) the National Natural Science Foundation of China (No. 40121303).
文摘Quantitative information on mass concentrations and other characteristics, such as spatial distribution, seasonal variation, indoor/outdoor (I/O) ratio, correlations and sources, of indoor and outdoor PM2.5 and elemental components in Guangzhou City were provided. Mass concentration of PM2.5 and elemental components were determined by standard weight method and proton-induced X-ray emission (PIXE) method. 18 elements were detected, the results showed positive results. Average indoor and outdoor PM2.5 concentrations in nine sites were in the range of 67.7-74.5μg/m^3 for summer period, and 109.9-123.7 μg/m^3 for winter period, respectively. The sum of 18 elements average concentrations were 5362.6-5533.4 ng/m^3 for summer period, and 8416.8-8900.6 ng/m^3 for winter period, respectively. Average concentrations of PM2.5 and element components showed obvious spatial characteristic, that the concentrations in roadside area and in industrial plant area were higher than those in generic urban area. An obvious seasonal variation characteristic was found for PM2.5 and elemental components, that the concentrations in winter were higher than that in summer. The I/O ratio of PM2.5 and some elemental components presented larger than 1 sometimes. According to indoor/outdoor correlation of PM2.5 and element concentrations, it was found that there were often good relationships between indoor and outdoor concentrations. Enrichment factors were calculated to evaluate anthropogenic versus natural elements sources.
文摘Polymer bonded explosive(PBX)formulations were successfully prepared in the laboratory scale containing 1,1-diamino-2,2-dinitroethene(FOX-7)and hexogen(RDX)as brisant high explosives and different binder types of polyurethane(PU)based on glycidyl azide polymer(GAP) and hydroxyl-terminated polybutadiene(HTPB) as an energetic and inert polymeric binder respectively.Casting technique was used for the preparation of different PBX formulations based on FOX-7/RDX and PU(GAP/HTPB)with 14% binder.The sensitivity to different initial impulses and performance characteristics of the explosive and lethal zone of the tested controlled fragmentation warhead by the fragmentation warhead assessment test(arena test)were studied,in which the arena test was carried out with a controlled fragmentation warhead made from Ck45 steel,with dimensions(100 mm length,30 mm outer diameter and 3 mm thickness).Results show that PBXGF4 has lower sensitivity to impact and heat than those of PBXGR4 by 188.4% and 3.2% respectively.Its friction sensitivity is the same as that of PBXGR4.It has better performance,in which detonation velocity increases by 2.1% and brisance increases by 0.5% when compared with those of PBXGR4.It was concluded that PBXGF4 which based on FOX-7 bonded with PU/GAP matrix has good characteristics as PBX,specially in the sensitivity to impact and can be applied for replacing PBXs based on RDX in the advanced PBXs for low sensitive fragmentation warheads.
基金Supported by the Natural Science Foundation of Department of Education (05Z008) and the Science and Technology Projects of Guangdong Province (2007B030101007).
文摘Cylindrical nickel metal hydride (Ni-MH) battery with high specific volume capacity was prepared by using the oxyhydroxide Ni(OH)2 and AB5 type hydrogen storage alloy and adjusting the designing parameters of positive and negative electrodes. The oxyhydroxide Ni(OH)2 was synthesized by oxidizing spherical β-Ni(OH)2 with chemical method. The X-ray diffraction (XRD) patterns and the Fourier transform infrared (PT-IR) spectra indicated that 7-NiOOH was formed on the oxyhydroxide Ni(OH)2 powders, and some H2O molecules were inserted into their crystal lattice spacing. The battery capacity could not be improved when the oxyhydroxide Ni(OH)2 sample was directly used as the positive active materials. However, based on the conductance and residual capacity of the oxyhydroxide Ni(OH)2 powders, AA size Ni-MH battery with 2560 mA.h capacity and 407 W·h·L^-1 specific volume energy at 0.2C was obtained by using the commercial spherical β-Ni(OH)2 and AB5-type hydrogen-storage alloy powders as the active materials when 10% mass amount of the oxyhydroxide Ni(OH)2 with 2.50 valence was added to the positive active materials and subsequently the battery designing parameters were adjusted as well. The as-prepared battery showed 70% initial capacity after 80 cycles at 0.5C. The possibility for adjusting the capacity ratio of positive and negative electrodes from 1 : 1.35 to 1 : 1.22 was demonstrated preliminarily. It is considered the as-prepared battery can meet the requirement of some special portable electrical instruments.
基金financially supported by the Youth talent support program of science and technology association of colleges of Shaanxi Province(Grant No.20190609)the Special scientific research plan of education department of Shaanxi province(Grant No.19JK0190 and 19JK0186)+3 种基金the Natural Science Foundation of Shaanxi Province(Grant No.2019JM508)the Open project of Key laboratory of catalytic foundation and application of Shaanxi province(Grant No.SLGPT2019KF01-23)the Opening Foundation of Shaanxi Key Laboratory of Industrial Automation(No.SLGPT2019KF01-10)the School-level project of Shaanxi University of Technology(Grant No.SLGRC03,SLGRC02)。
文摘With the discovery of graphene,black phosphorus(BP)has been rediscovered as a two-dimensional(2 D)layered material.Since its first preparation in 2014,2 D BP has elicited immense interest,and has exhibited excellent properties,such as distinct pleated structures in layers,adjustable direct bandgap,high carrier mobility,moderate on/off ratio,large specific surface area,and various interesting in-layer anisotropies.However,the realization of these excellent properties depends on the preparation of highquality 2 D BP sheets.Electrochemical exfoliation methods are typically performed under mild conditions,thus,these methods are convenient,controllable,and can produce high-quality 2 D BP sheets.This review summarizes research progress in BP sheets preparation through anodic,cathodic,and electrolyte exfoliation in recent years.Different exfoliating methods affect the quality of 2 D BP sheets.Moreover,possible exfoliating mechanisms and the potential applications of different exfoliating methods are summarized and discussed in detail.Lastly,the shortcomings of existing research on electrochemical exfoliation are presented,and suggestions and prospects for future research on the electrochemical exfoliation of 2 D BP are proposed.
基金was financially supported by the Joint Project of the National Natural Science Foundation of Chinathe Natural Science Foundation of Guangdong Province,China(No.U1134002),the Natural Science Foundation of Guangdong Province,China(No.10351063101000001)the Key Project of Science and Technology in Guangdong Province,China(No.2010A090602003)
文摘Dandelion-like TiO2 microspheres consisting of numerous rutile single-crystalline nanorods were synthesized for the first time by a hydrothermal method. Their crystal structure, morphology and electrochemical properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and galvanostatic charge and discharge tests. The results show that the synthesized TiO2 microspheres exhibit good rate and cycle performances as anode materials of lithium ion batteries. It can be found that the dandelion-like structure provides a larger specific surface area and the single-crystalline nanorod provides a stable structure and fast pathways for electron and lithium ion transport, which contribute to the rate and cycle performances of the battery.
基金Project(51090385) supported by the Major Program of the National Natural Science Foundation of ChinaProjects(121102000000160001,121102000000170013) supported by the Ministry of Land and Resources Department Budget,China+1 种基金Project(DD20179133) supported by the Geological Survey and Evaluation Project of ChinaProject(2018M641439) supported by China Postdoctoral Science Foundation
文摘Flotation is often employed to separate valuable natural minerals and gangue minerals.However,few studies have been conducted on artificial mineral flotation.Anosovite,the primary mineral in titanium slag,is a typical artificial mineral that can be enriched by flotation.In the present work,flotation behavior and adsorption mechanism of anosovite in salicylhydroxamic acid(SHA)solution were studied.The influence of pH and SHA dosage on anosovite flotability was investigated.Micro-flotation test results show that a pH range of 7–8.5 is available for SHA to collect anosovite.A maximum recovery of 93.26%can be obtained with SHA dosage of only 4×10.5 mol/L.In addition,TOC,zeta potential,FTIR,SEM-EDS,and XPS analyses were used to study the adsorption mechanism.Results demonstrated that SHA adsorption is governed by chemisorption.XPS studies further suggested that chemical adsorption occurred at the Ti sites on the anosovite surface.
基金Supported by the National Natural Science Foundation of China(21566013,51562016)Youth Science Foundation of Jiangxi Provincial Department of Education,China(GJJ170970)the Natural Science Foundation of Jiangxi Province(20171BAB206015)
文摘Membrane fouling is often considered as a hindrance for the application of microfiltration/ultrafiltration(MF/UF) for drinking water production. A novel process of photocatalytic membrane reactor/dynamic membrane(PMR/DM), operating in a continuous mode under sub-critical flux, was proposed for the mitigation of membrane fouling caused by humic acids(HAs) in water. The mechanism of membrane fouling alleviation with synergistic photocatalytic oxidation and dynamic layer isolating effect was comprehensively investigated from the characterization of foulant evolution responsible for the reversible and irreversible fouling. The results showed that the PMR/DM utilized photocatalytic oxidation to enhance the porosity and hydrophilicity of the fouling layer by converting the high molecular weight(MW) and hydrophobic HA molecules with carboxylic functional groups and aromatic structures into low-MW hydrophilic or transphilic fractions, including tryptophan-like or fulvic-like substances. The fouling layer formed in the PMR/DM by combination of photocatalytic oxidation and DM running at a sub-critical flux of 100 L·h^-1·m^-2, was more hydrophilic and more porous, resulting in the lowest trans-membrane pressure(TMP) growth rates, as compared to the processes of ceramic membrane(CM), DM and PMR/CM.Meanwhile, the dynamic layer prevented the foulants, particularly the high-MW hydrophobic fractions,from contacting the primary membrane, which enabled the membrane permeability to be restored easily.
基金the National Natural Science Foundation of China (20772037)the Natural Science Foundation of Guangdong Province (06025033)
文摘Two dinuclear compounds [Ln2(acetate)6(H2O)4]-4H2O (Ln=Tb(1), Sm(2)) were obtained by the hydrothermal reaction of Ln2O3 with malonic acid at 150 ℃. Both compounds were characterized by elemental analyses, infrared spectra, and single crystal X-ray diffraction. The results showed that complexes 1 and 2 were isomorphous and crystallize in triclinic space group P 1. The coordination geometry around Ln(Ⅲ) ions in the complexes 1 and 2 was a distorted tricapped trigonal prism with a nine coordination. In the crystal, the molecular organization was further stabilized by well-defined weak hydrogen bonding interactions between the neutral dinuclear molecular units that led to the formation of a three-dimensional network. The fluorescence properties of the two complexes 1 and 2 in organic solvents were also studied. The results show that the ligand acetate favored energy transfer to the emitting energy level of Tb(Ⅲ) in complex 1. Some factors that influence the fluorescent intensity were also discussed in the article.
基金the financial support by the National Natural Science Foundation of China(Grant nos.21605090,31600527)。
文摘Organic–inorganic perovskites solar cells(PSCs)have attracted great attention due to their rapid progress in power conversion efficiency(PCE).However,there is still an enormous challenge to achieve both high efficiency and stability devices as the decomposition of perovskite materials under humid and light conditions.Herein,we demonstrate that high efficiency and stability of PSCs can be obtained by the reaction of three-dimensional(3D)perovskite with 1,4-butanediamine iodide(BEAI2)vapor.The incorporation of BEAI2 intensively promotes the crystallization of perovskite film with large grain size(~500 nm).Further characterization reveals that the post-treatment perovskite film delivered low interface trap density with long carrier lifetime(>200 ns),long carrier diffusion length(>600 nm)and large carrier mobility(>1.5 cm^2 V-1S-1).Solar cells employing such post-treatment films demonstrated 19.58%PCE without hysteresis.Moreover,the post-treatment devices can retain over 90%original efficiencies stored under ambient atmospheric conditions and exhibit better stability under 85℃and continuous illumination as a two-dimensional(2D)perovskite thin layer is formed on the surface/or at the grain boundaries of 3D perovskite.This study offers an effective way to obtain PSCs with high efficiency and stability.
基金Supported by the Natural Science Foundation of Jiangsu Province under Grant No BK20160292the Natural Science Foundation of the Higher Educations Institutions of Jiangsu Province under Grant No 16KJB150013+1 种基金the National Natural Science Foundation of China under Grant No U1404505the Program for Innovative Talent in University of Henan Province under Grant No16HASTIT010
文摘Superconducting vanadium nitride (VN) is successfully synthesized by a solid-state reaction of vanadium pentox- ide, sodium amide and sulfur in an autoclave at a relatively low temperature (240-400℃). The obtained samples are characterized by x-ray diffraction, x-ray photoelectron spectroscopy and transmission electron microscopy. The result of the magnetization of the obtained VN product as a function of temperature indicates that the onset superconducting transition temperature is about 8.4K. Furthermore, the possible reaction mechanism is also discussed.
基金financially supported by the National Natural Science Foundation of China(No.21473062)Guizhou Z [(2015)4002]Guizhou GNYL[(2017)008] of Guizhou Province,China
文摘Two new coordination polymers(CPs) based on two new tetrazole-based ligands, namely, [Cu(TPP)]n(HTTP = 4-(3-(2 H-tetrazol-5-yl)phenyl)pyridine, 1) and {[Cd_2(TBCA)_2(H_2O)_2]·-H_2O}n(H_2TBCA = 3?-(2 H-tetrazol-5-yl)biphenyl-4-carboxylic acid, 2), were synthesized via solvothermal reactions. Single-crystal X-ray diffraction analysis reveals that compound 1 exhibits a(3,6)-connected rtl network topology based on binuclear secondary building units(SBUs). Compound 2 presents a 2D framework composed of 1D SUBs formed by both carboxyl and tetrazole groups. The 2D network is linked into a 3D framework via various hydrogen bonds. They represent two examples of CPs construct from rigid 5-substitued tetrazole-based ligands with relatively longer spacer. The thermal stabilities and luminescent properties of compounds 1 and 2 were also explored.