In this study,the solid structure,dissolution behavior,thermodynamic properties and nucleation kinetics of malonamide were explored.Firstly,the Hirshfeld surface analysis and molecular electrostatic potential surface ...In this study,the solid structure,dissolution behavior,thermodynamic properties and nucleation kinetics of malonamide were explored.Firstly,the Hirshfeld surface analysis and molecular electrostatic potential surface were plotted to reveal the percentage contribution of various intermolecular contacts and location of the strongest hydrogen bond.Next,the solubility of malonamide in 12 solvents was determined by dynamic method at temperatures from 278.15 K to 318.15 K.Four thermodynamic models were applied to analyze solubility results.In addition,the thermodynamic properties were calculated to further analyze and discuss the dissolution behavior of malonamide.Moreover,the physicochemical properties of solvents were explored to express the solvent effects.The results illustrate“like dissolves like”,“mass transfer”and“solvent–solute interaction”rules play the synergistic effects on the dissolution process.The molecular dynamic simulation,including radial distribution function analysis and solvent free energy,was used to further explain the dissolution behavior.At last,the nucleation rate and effective interfacial energy in methanol solvent was measured and calculated to reveal the nucleation behaviour.展开更多
To explore the response law of non-lethal large-size kinetic energy projectiles to blunt attack on skin tissue,and to evaluate the skin injury characteristics of the attacked personnel and the use safety of kinetic en...To explore the response law of non-lethal large-size kinetic energy projectiles to blunt attack on skin tissue,and to evaluate the skin injury characteristics of the attacked personnel and the use safety of kinetic energy projectiles.Based on the LS-DYNA simulation software,a three-layer skin simulation model and a Flash-Ball rubber bullet model are established,and the force-time and deformation-time biomechanical corridors of the Flash-Ball rubber bullet impacting human skin tissue are obtained.The corridor curve and the energy transfer and diffusion are analyzed and compared.The safety evaluation of the damage caused by the rubber bullet shooting a human body at different distances is carried out using the empirical formula of the penetration limit.Finally,the safe shooting distance is obtained.The results show that the model used in the simulation has a good correlation with the experimental data,its biomechanical corridor characteristics are different from those of conventional vehicle impact and smallsize projectile response characteristics.The energy transfer and action time of medium and low-speed impact may cause greater damage.The fat layer is the largest energy absorption unit.The minimum safe shooting distance to ensure skin tissue from penetrating damage is 15.8 m,and the limit specific kinetic energy of skin damage is 7.88 J/cm^(2).This study can be extended to the study of biomechanical response law and safety evaluation under the impact of the same type of large kinetic energy projectile,which provides an important theoretical reference for the police to use large kinetic energy projectiles to conduct safe shooting in peacekeeping operations.展开更多
OER catalyst of Ni_(3)Fe/Ni_(4)S_(3)/Ni/C(NiFeSC series)mixed crystal composite nanofibers was prepared by electrospinning and atmospheric heat treatment process.The testing results indicate that the diameters of Ni_(...OER catalyst of Ni_(3)Fe/Ni_(4)S_(3)/Ni/C(NiFeSC series)mixed crystal composite nanofibers was prepared by electrospinning and atmospheric heat treatment process.The testing results indicate that the diameters of Ni_(3)Fe/Ni_(4)S_(3)/Ni/C composite nanofibers is about 200 nm,the grains size is about 1-3 nm,and the fiber surface is rough.The electrochemical test results show that the heterojunction of the prepared Ni_(3)Fe/Ni_(4)S_(3)/Ni/C hybrid crystal composite nanofiber has synergistic effect with sulfide,and exhibits good electrocatalytic activity of water decomposition and OER in alkaline system.The OER electrocatalytic performance of Ni_(3)Fe/Ni_(4)S_(3)/Ni/C composite electrode prepared via a heat treatment at 1000℃process was tested in 1 mol/L KOH electrolytes.The results show that the overpotential is about 298 mV,the Tafel slope is about 74 mV?dec-1,and the surface resistance is about 1.69Ω·cm^(2),at the current density of 10 mA·cm^(-2).展开更多
A smart response fluid was designed and developed to overcome the challenges of gas channeling during CO_(2)flooding in low-permeability,tight oil reservoirs.The fluid is based on Gemini surfactant with self-assembly ...A smart response fluid was designed and developed to overcome the challenges of gas channeling during CO_(2)flooding in low-permeability,tight oil reservoirs.The fluid is based on Gemini surfactant with self-assembly capabilities,and the tertiary amine group serves as the response component.The responsive characteristics and corresponding mechanism of the smart fluid during the interaction with CO_(2)/oil were studied,followed by the shear characteristics of the thickened aggregates obtained by the smart fluid responding to CO_(2).The temperature and salt resistance of the smart fluid and the aggregates were evaluated,and their feasibility and effectiveness in sweep-controlling during the CO_(2)flooding were confirmed.This research reveals:(1)Thickened aggregates could be assembled since the smart fluid interacted with CO_(2).When the mass fraction of the smart fluid ranged from 0.05%to 2.50%,the thickening ratio changed from 9 to 246,with viscosity reaching 13 to 3100 mPas.As a result,the sweep efficiency in low-permeability core models could be increased in our experiments.(2)When the smart fluid(0.5%to 1.0%)was exposed to simulated oil,the oil/fluid interfacial tension decreased to the level of 1×10^(-2)mN/m.Furthermore,the vesicle-like micelles in the smart fluid completely transformed into spherical micelles when the fluid was exposed to simulated oil with the saturation greater than 10%.As a result,the smart fluid could maintain low oil/fluid interfacial tension,and would not be thickened after oil exposure.(3)When the smart fluid interacted with CO_(2),the aggregates showed self-healing properties in terms of shear-thinning,static-thickening,and structural integrity after several shear-static cycles.Therefore,this fluid is safe to be placed in deep reservoirs.(4)The long-term temperature and salt resistance of the smart fluid and thickened aggregates have been confirmed.展开更多
Colloidal particles,heterogeneous mixture with various organic components and continuous molecular weight(MW)distribution,is omnipresent in lake sediments and substantially influence the retention,transportation,and f...Colloidal particles,heterogeneous mixture with various organic components and continuous molecular weight(MW)distribution,is omnipresent in lake sediments and substantially influence the retention,transportation,and fate of contaminants in lake ecosystem.We sampled and extracted sedimentary colloids from different ecology regions in Taihu Lake,Jiangsu,East China,in June 2020,and they were further separated into four different particle size ranges by tangent ultrafiltration,and the properties of colloids were studied in various methods,including zeta potential analysis,transmission electron micrograph images(TEM),Fourier transformation infrared(FTIR),and 3D fluorescence.Results show that the surface of the colloids is covered with organic macromolecular substances,such as humuslike substances and protein-like substances.There were significant differences in molecular weight and fraction content of colloids in the sediments from macrophyte-dominant(MD)area and algae-dominant(AD)area in the lake.Colloids from MD area are mainly composed of humic acid,protein,and fulvic acid;the content of fulvic acid is lower than that of humic acid and protein.The humic acid exists mainly in small molecular weight(10-100 kDa),protein exists in mainly large molecular weight colloids(0.45-1μm).Colloids from AD area are mainly composed of humic acid,and mainly distributed in the molecular weight(10 kDa-0.45μm).The presence of humic acid inhibits effectively the agglomeration of the colloids.Especially,the stability of colloids is closely related to the molecular weight,with low molecular weight from MD area show higher stability.The existence of humic acid in colloids increases the electrostatic repulsion between colloidal particles,which can effectively inhibit the agglomeration of colloids,thus enhancing the stability of colloids.Furthermore,both monovalent and divalent electrolytes enhance colloidal aggregation,and the low-molecular-weight(LMW)colloid fraction exhibits higher stability efficiency than the high-molecular-weight(HMW)colloidal.展开更多
The safe operating voltage and low volume variation of Li_(3)VO_(4)(LVO)make it an ideal anode material for lithium(Li)-ion batteries.However,the insufficient understanding of the inner storage mechanism hinders the d...The safe operating voltage and low volume variation of Li_(3)VO_(4)(LVO)make it an ideal anode material for lithium(Li)-ion batteries.However,the insufficient understanding of the inner storage mechanism hinders the design of LVO-based electrodes.Herein,we investigate,for the first time,the Li-ion storage activity in LVO via Cl doping.Moreover,N-doped C coating was simultaneously achieved in the Cl doping process,resulting in synergistically improved reaction kinetics.As a result,the as-prepared Cl-doped Li_(3)VO_(4) coated with N-doped C(Cl-LVO@NC)electrodes deliver a discharge capacity of 884.1 mAh/g after 200 cycles at 0.2 A/g,which is the highest among all of the LVO-based electrodes.The Cl-LVO@NC electrodes also exhibit high-capacity retention of 331.1 mAh/g at 8.0 A/g and full capacity recovery after 5 periods of rate testing over 400 cycles.After 5000 cycles at 4.0 A/g,the discharge capacity can be maintained at 423.2 mAh/g,which is superior to most LVO-based electrodes.The Li-ion storage activity in LVO via Cl doping and significant improvement in the high-rate Li-ion storage reported in this work can be used as references for the design of advanced LVO-based electrodes for high-power applications.展开更多
A self-made directional solidification device was used to fabricate d 80 mm high purity aluminum ingots. SEM and AFM were used to detect the shape of grain boundaries. The orientation of the grain was studied by X-ray...A self-made directional solidification device was used to fabricate d 80 mm high purity aluminum ingots. SEM and AFM were used to detect the shape of grain boundaries. The orientation of the grain was studied by X-ray diffractometry. The results show that the nucleation points locate at the intersections of three adjacent grains. The lattice orientation of grains does not alter in the horizontal direction, but gradually approaches the optimum growth direction in the vertical direction during the growth process. All the grains suffer the competition and only the one whose orientation is closest to the preferred direction can occupy the final growth space.展开更多
In this study,low-field nuclear magnetic resonance(LF-NMR)was used to collect the transverse relaxation signals of camphor seeds that had been dried at different temperatures and for different durations.The transverse...In this study,low-field nuclear magnetic resonance(LF-NMR)was used to collect the transverse relaxation signals of camphor seeds that had been dried at different temperatures and for different durations.The transverse relaxation time of the hydrogen nucleus was obtained by SIRT(Simultaneous Iterative Reconstruction Technique)inversion,and the correlation between the moisture content on dry basis and the amplitude of NMR signal of camphor seeds sampled at different drying stages was analyzed.The results showed that water existed in three main forms strongly bound water,weakly bound water and free water in camphor seeds.During the drying process,the peak position of strongly bound water remained unchanged,but the peak positions of weakly bound water and free water fluctuated.Drying rate increased with drying temperature increasing.In addition,there was a very significant linear relationship between the total NMR signal amplitude and moisture content on dry basis,and the correlation coefficient reached 0.984 4.展开更多
The priming effect(PE)induced by biochar provides a basis for evaluating its carbon(C)sequestration potential in soils.A 60 days’laboratory incubation was conducted,which involved the amendment of biochar(1%of soil m...The priming effect(PE)induced by biochar provides a basis for evaluating its carbon(C)sequestration potential in soils.A 60 days’laboratory incubation was conducted,which involved the amendment of biochar(1%of soil mass)produced from rice straw at 300℃(B300)and 500℃(B500)to young(Y)and old(O)poplar plantation soils,with the aim of studying the responses of biochar-induced PEs to poplar plantation ages.This incubation included six treatments:Y+CK(control),Y+B300,Y+B500,O+CK,O+B300,and O+B500.Carbon dioxide(CO_(2))emissions were significantly increased(p<0.05)in the B300 amended soils,while it was decreased in the B500 amended soils compared to the CK.The primed CO_(2) emissions were 2.35 times higher in the Y+B300 than the O+B300 treatments,which was measured to be 18.6 and 5.56 mg C·kg^(-1) with relative PEs of 12.4%and 3.35%,respectively.However,there was little difference between the primed CO_(2) emissions in Y+B500 and O+B500 treatments,which were measured to be-24.9 and-29.6 mg·C·kg^(-1) with relative PEs of-16.6%and-17.8%,respectively.Dissolved organic carbon(DOC)was significantly lower in the young poplar plantation soil than that in the old poplar plantation soil regardless of biochar amendment throughout the incubation,indicating greater C-limit of soil microorganisms in the young poplar plantation soil.Using ^(13)C isotope tracing,neither B300 nor B500 decreased native soil-derived DOC,which indicated that the negative B500-induced PEs were not due to a reduction in the availability of native soil-derived C.In conclusion,the response of biochar-induced PEs to poplar plantation age depends on biochar types while soil available C indirectly affects biochar-induced PEs.Further studies should focus on how the interactive effects between soil C availability and microbial community impacts biochar-induced PEs.展开更多
Nickel oxalate micro-spheres with core-shell structure of solid core and radiate shell were synthesized by precipitation method in a mixed water solution, with oxalic acid and nickel acetate as raw materials, through ...Nickel oxalate micro-spheres with core-shell structure of solid core and radiate shell were synthesized by precipitation method in a mixed water solution, with oxalic acid and nickel acetate as raw materials, through dropping ammonium hydroxide to adjust the solution pH value to about 8.0. Nickel microspheres with core-shell structure of solid core and porous shell were prepared by decomposing of nickel oxalate microspheres precursor at about 340 ℃ in argon atmosphere. The analyses of infrared spectroscopy(IR)indicates that the composition of the powders is nickel oxalate. The analyses of atomic absorption spectrometry(AAS) and organic elemental analysis(OEA) indicate that the molar ratio of(C2O4)^2-/Ni^2+ is about 1.02, close to the theoretical value of 1.0. The results of the thermo-gravimetric and differential thermal gravity analyses(TG-DTG) indicate that the molar ratio of(C2O4)^2-/Ni^2+ is about 1.06, also close to the theoretical value of 1.0.The analysis of X-ray diffraction(XRD) indicates that the composition of black powders as-prepared is nickel,which has a face-centered cubic crystal structure with average crystal grain size about 16.87 nm. The images of scanning electron microscopy(SEM) indicate that the morphology of nickel oxalate microspheres is a coreshell structure with solid core and radiate shell. The diameter of nickel oxalate microspheres is about 3 μm, and the shell consists of a large number of thin nanorods. The images of SEM also indicate that the morphology of nickel microspheres is a core-shell structure with solid core and porous shell. The diameter of nickel microspheres is about 2 μm, and the shell consists of a large number of nickel grains, surface holes and through holes. The diameter of nickel grains is about 50-100 nm, and the diameter of holes is about 50-200 nm.展开更多
Chinese herbal medicine additives can not only directly improve the growth performance of chickens,but also indirectly affect the growth of chickens by enhancing the antioxidant capacity,immunity and disease resistanc...Chinese herbal medicine additives can not only directly improve the growth performance of chickens,but also indirectly affect the growth of chickens by enhancing the antioxidant capacity,immunity and disease resistance of the body,and eliminating diseases and adverse factors,thereby improving the growth performance of chickens.In the context of the current national prohibition of adding antibiotics to feed,the research and application of Chinese herbal medicine additives are of practical significance to eliminate the long-term use of antibiotics as chicken feed additives and reduce the threat to the environment and human health.For this reason,the research related to the substitution of Chinese herbal medicine for antibiotics is made a brief introduction to provide a reference in research and production practice.展开更多
Highly dispersed gadolinium zirconate(GZ)nanoparticles with fluorite structure were successfully synthesized by co-precipitation method,and their phase composition and microstructure,formation mechanism,and grain grow...Highly dispersed gadolinium zirconate(GZ)nanoparticles with fluorite structure were successfully synthesized by co-precipitation method,and their phase composition and microstructure,formation mechanism,and grain growth kinetics were investigated.The results suggest that the nanoparticles were obtained through hydroxide dehydration and solid phase reaction.High dispersion was accomplished by ethanol solvent to reduce the hydrogen bond and sodium dodecyl benzene sulfonate(SDBS)surfactant to increase the electrostatic repulsion between the nanoparticles.The grain growth activation energy of GZ powders calcined at lower temperature(<1200°C)is 86.5 kJ/mol(Ql),and the grain growth activation energy of GZ powders calcined at higher temperature(>1200°C)is 148.4 kJ/mol(Qh).The current study shows that the optimal process to synthesize dispersed GZ nanoparticles includes ethanol solvent,3 wt.%SDBS surfactant,and 1100°C as calcining temperature.展开更多
Little is known about the roles of dynorphin and Kappa opioid receptor(KOR) in mollusks. In this study, we aim to determine the distribution of dynorphin A and KOR-1 in the digestive system of the scallop Chlamys farr...Little is known about the roles of dynorphin and Kappa opioid receptor(KOR) in mollusks. In this study, we aim to determine the distribution of dynorphin A and KOR-1 in the digestive system of the scallop Chlamys farreri. Using immunohistochemical staining, we confirmed the expression of dynorphin A and KOR-1 in the digestive system of C. farreri. Dynorphin A immunopositive cells were identified in intestine and hepatopancreas. In intestine, small and spherical dynorphin A immunopositive cells(4–9 μm in diameter) were scattered among the long columnar epithelial cells(ECs). In hepatopancreas, cells containing masses(5–14 μm in diameter) of dynorphin A immunopositive products were observed in epithelium of acinis. These immunopositive cells may be synthetic and/or secretory cells of dynorphin A. Dynorphin A immunoreactive products were commonly observed in epithelium and connective tissue(CT) of labial palps, mouth labia and stomach, which presented in forms of grains, fibers or flakes. KOR-1 immunoreactive material was observed in ECs and CTs of labial palps, mouth labia and stomach, intestine and hepatopancreas. The distribution of both dynorphin A and KOR-1 in the digestive organs suggests an involvement of dynorphin via KOR-1 in the functional regulation of the digestive system of C. farreri.展开更多
Non- focused ion beams may be employed to investigate the surface profile and the shape of microscopic objects or periodic surfaces by using the known stopping powers of ions in solids. The energy spectra of the scatt...Non- focused ion beams may be employed to investigate the surface profile and the shape of microscopic objects or periodic surfaces by using the known stopping powers of ions in solids. The energy spectra of the scattered or reaction ions are recorded as a function of the angles between the beam, the object and the detector, and of the energy of incident ions. The shape parameters may then be determined using computer codes. Presented also are the typical experimental results.展开更多
Zn_(1-x)Cu_xO thin films were synthesized by the radio frequency (RF) magnetronsputtering technique using a ZnO target containing different pieces of small Cu-chips. X-raydiffraction (XRD) and scanning electron micros...Zn_(1-x)Cu_xO thin films were synthesized by the radio frequency (RF) magnetronsputtering technique using a ZnO target containing different pieces of small Cu-chips. X-raydiffraction (XRD) and scanning electron microscopy (SEM) were employed to analyze the crystallineand microstructure of the fihn, and X-ray photoelectron spectroscopy (XPS) was used toestablish the bonding characteristics and oxidation states of copper inside the ZnO host. Roomtemperature (RT) ferromagnetism was observed in the Zn_(1-x)Cu_xO films by a Quantum Designsuperconducting quantmn interference device (SQUID) and the saturation magnetic moment ofthe films was found to decrease with the increase in Cu content.展开更多
To identify the aggregates causing the alkali-silica reaction,and the reactivity of rocks in different parts of China,the mineral and texture characteristics of some typical coarse ag-gregates and the alkali reactivit...To identify the aggregates causing the alkali-silica reaction,and the reactivity of rocks in different parts of China,the mineral and texture characteristics of some typical coarse ag-gregates and the alkali reactivity of these aggregates were systematically investigated.On one hand,petrographic examination of aggregates,combined with X-ray diffraction analysis,chemical analysis,scanning electron microscopy,was conducted for analyzing their mineralogy and texture.It was found that not only mineral characteristics,but also their interior structure would affect their potential alkali-silica reactivity.Furthermore,the alkali-silica reactivity of aggregates is due to their mineral compositions,such as containing different alkali-reactive minerals,while,different stuc-tures of those aggregates with similar minerals affect their reactivity to some extent.There are some amount of micro-aperture and cracks across the quartz in the aggregate,which may become the natural accesses for Na+,K+,and OH-ions to intrude in the mortar or concrete during the process of alkali-silica reaction.Alkali-silica reactivity of the aggregates was detected by the accelerated mortar bars test.It was revealed that all the aggregates tested were alkali-silica reactive and the re-sults were also in accordance with their mineral and structure analysis.展开更多
A new concept, called the row–column visibility graph, is proposed to map two-dimensional landscapes to complex networks. A cluster coverage is introduced to describe the extensive property of node clusters on a Eucl...A new concept, called the row–column visibility graph, is proposed to map two-dimensional landscapes to complex networks. A cluster coverage is introduced to describe the extensive property of node clusters on a Euclidean lattice. Graphs mapped from fractals generated with the probability redistribution model behave scale-free. They have pattern-induced hierarchical organizations and comparatively much more extensive structures. The scale-free exponent has a negative correlation with the Hurst exponent, however, there is no deterministic relation between them. Graphs for fractals generated with the midpoint displacement model are exponential networks. When the Hurst exponent is large enough(e.g., H >0.5), the degree distribution decays much more slowly, the average coverage becomes significant large, and the initially hierarchical structure at H < 0.5 is destroyed completely. Hence, the row–column visibility graph can be used to detect the pattern-related new characteristics of two-dimensional landscapes.展开更多
Perovskite-type oxide has a general formula ABO_3. Both the lattice A- and lattice B-sites can be occupied by two kinds of metallic ions, forming substituted perovskites such as La_(1-x)Sr_xCoO_3-d and LaFe_xCo_(1-x)O...Perovskite-type oxide has a general formula ABO_3. Both the lattice A- and lattice B-sites can be occupied by two kinds of metallic ions, forming substituted perovskites such as La_(1-x)Sr_xCoO_3-d and LaFe_xCo_(1-x)O_3. In the present work, we aim to investigate competitive occupying of Fe^(3+) and Co^(3+) ions into the lattice B-sites of perovskite LaFe_xCo_(1-x)O_3 formed under the condition of excess feeding of Fe^(3+) and Co^(2+) ions relative to the La^(3+) ions. For this purpose, standard curve of normalized cell volumes(NCVs) of a defined series of perovskites LaFe_xCo_(1-x)O_3 versus the x values was plotted. Lattice occupancy of Fe^(3+) ions at the B-sites of the perovskite LaFe_xCo_(1-x)O_3 was then determined from the standard curve. It is proved that Fe^(3+) ions were capable of occupying preferentially into the lattice B-sites of the perovskite crystalline structure.展开更多
The structural, magnetic properties, and electronic structures of hexagonal Fe Co Sn compounds with as-annealed bulk and ribbon states were investigated by x-ray powder diffraction(XRD), differential scanning calorime...The structural, magnetic properties, and electronic structures of hexagonal Fe Co Sn compounds with as-annealed bulk and ribbon states were investigated by x-ray powder diffraction(XRD), differential scanning calorimetry(DSC), transmission electron microscope(TEM), scanning electron microscope(SEM), magnetic measurements, and first-principles calculations. Results indicate that both states of FeCoSn show an Ni_2In-type hexagonal structure with a small amount of FeCo-rich secondary phase. The Curie temperatures are located at 257 K and 229 K, respectively. The corresponding magnetizations are 2.57 μB/f.u. and 2.94 μB/f.u. at 5 K with a field of 50 kOe(1 Oe = 79.5775 A·m^(-1)). The orbital hybridizations between 3 d elements are analyzed from the distribution of density of states(DOS), showing that Fe atoms carry the main magnetic moments and determine the electronic structure around Fermi level. A peak of DOS at Fermi level accounts for the presence of the FeCo-rich secondary phase. The Ni_2In-type hexagonal FeCoSn compound can be used during the isostructural alloying for tuning phase transitions.展开更多
基金financially supported by the Innovative Group Project of China (21621004)Demonstration Project of Integration of Science, Education and Industry in Qilu University of Technology (2020KJC-ZD09)
文摘In this study,the solid structure,dissolution behavior,thermodynamic properties and nucleation kinetics of malonamide were explored.Firstly,the Hirshfeld surface analysis and molecular electrostatic potential surface were plotted to reveal the percentage contribution of various intermolecular contacts and location of the strongest hydrogen bond.Next,the solubility of malonamide in 12 solvents was determined by dynamic method at temperatures from 278.15 K to 318.15 K.Four thermodynamic models were applied to analyze solubility results.In addition,the thermodynamic properties were calculated to further analyze and discuss the dissolution behavior of malonamide.Moreover,the physicochemical properties of solvents were explored to express the solvent effects.The results illustrate“like dissolves like”,“mass transfer”and“solvent–solute interaction”rules play the synergistic effects on the dissolution process.The molecular dynamic simulation,including radial distribution function analysis and solvent free energy,was used to further explain the dissolution behavior.At last,the nucleation rate and effective interfacial energy in methanol solvent was measured and calculated to reveal the nucleation behaviour.
文摘To explore the response law of non-lethal large-size kinetic energy projectiles to blunt attack on skin tissue,and to evaluate the skin injury characteristics of the attacked personnel and the use safety of kinetic energy projectiles.Based on the LS-DYNA simulation software,a three-layer skin simulation model and a Flash-Ball rubber bullet model are established,and the force-time and deformation-time biomechanical corridors of the Flash-Ball rubber bullet impacting human skin tissue are obtained.The corridor curve and the energy transfer and diffusion are analyzed and compared.The safety evaluation of the damage caused by the rubber bullet shooting a human body at different distances is carried out using the empirical formula of the penetration limit.Finally,the safe shooting distance is obtained.The results show that the model used in the simulation has a good correlation with the experimental data,its biomechanical corridor characteristics are different from those of conventional vehicle impact and smallsize projectile response characteristics.The energy transfer and action time of medium and low-speed impact may cause greater damage.The fat layer is the largest energy absorption unit.The minimum safe shooting distance to ensure skin tissue from penetrating damage is 15.8 m,and the limit specific kinetic energy of skin damage is 7.88 J/cm^(2).This study can be extended to the study of biomechanical response law and safety evaluation under the impact of the same type of large kinetic energy projectile,which provides an important theoretical reference for the police to use large kinetic energy projectiles to conduct safe shooting in peacekeeping operations.
基金Funded by the Doctoral Fund of Chengdu University (2081919131)the Open Fund of Material Corrosion and Protection Key Laboratory of Sichuan Province (2021CL27)the Sichuan Science and Technology Program (2023YFG0229)。
文摘OER catalyst of Ni_(3)Fe/Ni_(4)S_(3)/Ni/C(NiFeSC series)mixed crystal composite nanofibers was prepared by electrospinning and atmospheric heat treatment process.The testing results indicate that the diameters of Ni_(3)Fe/Ni_(4)S_(3)/Ni/C composite nanofibers is about 200 nm,the grains size is about 1-3 nm,and the fiber surface is rough.The electrochemical test results show that the heterojunction of the prepared Ni_(3)Fe/Ni_(4)S_(3)/Ni/C hybrid crystal composite nanofiber has synergistic effect with sulfide,and exhibits good electrocatalytic activity of water decomposition and OER in alkaline system.The OER electrocatalytic performance of Ni_(3)Fe/Ni_(4)S_(3)/Ni/C composite electrode prepared via a heat treatment at 1000℃process was tested in 1 mol/L KOH electrolytes.The results show that the overpotential is about 298 mV,the Tafel slope is about 74 mV?dec-1,and the surface resistance is about 1.69Ω·cm^(2),at the current density of 10 mA·cm^(-2).
基金Supported by the PetroChina Science and Technology Major Project(2019-E2607)PetroChina Exploration and Production Company Science and Technology Project(KS2020-01-09).
文摘A smart response fluid was designed and developed to overcome the challenges of gas channeling during CO_(2)flooding in low-permeability,tight oil reservoirs.The fluid is based on Gemini surfactant with self-assembly capabilities,and the tertiary amine group serves as the response component.The responsive characteristics and corresponding mechanism of the smart fluid during the interaction with CO_(2)/oil were studied,followed by the shear characteristics of the thickened aggregates obtained by the smart fluid responding to CO_(2).The temperature and salt resistance of the smart fluid and the aggregates were evaluated,and their feasibility and effectiveness in sweep-controlling during the CO_(2)flooding were confirmed.This research reveals:(1)Thickened aggregates could be assembled since the smart fluid interacted with CO_(2).When the mass fraction of the smart fluid ranged from 0.05%to 2.50%,the thickening ratio changed from 9 to 246,with viscosity reaching 13 to 3100 mPas.As a result,the sweep efficiency in low-permeability core models could be increased in our experiments.(2)When the smart fluid(0.5%to 1.0%)was exposed to simulated oil,the oil/fluid interfacial tension decreased to the level of 1×10^(-2)mN/m.Furthermore,the vesicle-like micelles in the smart fluid completely transformed into spherical micelles when the fluid was exposed to simulated oil with the saturation greater than 10%.As a result,the smart fluid could maintain low oil/fluid interfacial tension,and would not be thickened after oil exposure.(3)When the smart fluid interacted with CO_(2),the aggregates showed self-healing properties in terms of shear-thinning,static-thickening,and structural integrity after several shear-static cycles.Therefore,this fluid is safe to be placed in deep reservoirs.(4)The long-term temperature and salt resistance of the smart fluid and thickened aggregates have been confirmed.
基金Supported by the National Natural Science Foundation of China(Nos.42007332,51979137)the Natural Science Foundation of Jiangsu Province(No.20KJB610001)。
文摘Colloidal particles,heterogeneous mixture with various organic components and continuous molecular weight(MW)distribution,is omnipresent in lake sediments and substantially influence the retention,transportation,and fate of contaminants in lake ecosystem.We sampled and extracted sedimentary colloids from different ecology regions in Taihu Lake,Jiangsu,East China,in June 2020,and they were further separated into four different particle size ranges by tangent ultrafiltration,and the properties of colloids were studied in various methods,including zeta potential analysis,transmission electron micrograph images(TEM),Fourier transformation infrared(FTIR),and 3D fluorescence.Results show that the surface of the colloids is covered with organic macromolecular substances,such as humuslike substances and protein-like substances.There were significant differences in molecular weight and fraction content of colloids in the sediments from macrophyte-dominant(MD)area and algae-dominant(AD)area in the lake.Colloids from MD area are mainly composed of humic acid,protein,and fulvic acid;the content of fulvic acid is lower than that of humic acid and protein.The humic acid exists mainly in small molecular weight(10-100 kDa),protein exists in mainly large molecular weight colloids(0.45-1μm).Colloids from AD area are mainly composed of humic acid,and mainly distributed in the molecular weight(10 kDa-0.45μm).The presence of humic acid inhibits effectively the agglomeration of the colloids.Especially,the stability of colloids is closely related to the molecular weight,with low molecular weight from MD area show higher stability.The existence of humic acid in colloids increases the electrostatic repulsion between colloidal particles,which can effectively inhibit the agglomeration of colloids,thus enhancing the stability of colloids.Furthermore,both monovalent and divalent electrolytes enhance colloidal aggregation,and the low-molecular-weight(LMW)colloid fraction exhibits higher stability efficiency than the high-molecular-weight(HMW)colloidal.
基金supported by the National Natural Science Foundation of China(No.52101262)Distinguished Youth Foundation of Hubei Province(2019CFA084)+1 种基金Educational offi ce of Hubei Province(Q20201201)the 111 project(D20015).
文摘The safe operating voltage and low volume variation of Li_(3)VO_(4)(LVO)make it an ideal anode material for lithium(Li)-ion batteries.However,the insufficient understanding of the inner storage mechanism hinders the design of LVO-based electrodes.Herein,we investigate,for the first time,the Li-ion storage activity in LVO via Cl doping.Moreover,N-doped C coating was simultaneously achieved in the Cl doping process,resulting in synergistically improved reaction kinetics.As a result,the as-prepared Cl-doped Li_(3)VO_(4) coated with N-doped C(Cl-LVO@NC)electrodes deliver a discharge capacity of 884.1 mAh/g after 200 cycles at 0.2 A/g,which is the highest among all of the LVO-based electrodes.The Cl-LVO@NC electrodes also exhibit high-capacity retention of 331.1 mAh/g at 8.0 A/g and full capacity recovery after 5 periods of rate testing over 400 cycles.After 5000 cycles at 4.0 A/g,the discharge capacity can be maintained at 423.2 mAh/g,which is superior to most LVO-based electrodes.The Li-ion storage activity in LVO via Cl doping and significant improvement in the high-rate Li-ion storage reported in this work can be used as references for the design of advanced LVO-based electrodes for high-power applications.
基金This work was financially supported by the Major State Basic Besearch Development Program of China (No.2005CB623704)The authors wish to thank professors Shao B.L.and Liu A.S.(National Analysis and Testing Center for Nonferrous Metals & Electronic Materials,General Research Institute for Nonferrous Metals) for the TEM work,and Li Y.L.(Analysis and Test Center,Beijing Normal University) for SEM work.
基金Project(2002AA6070) supported by the Hi-tech Research and Development Program of China
文摘A self-made directional solidification device was used to fabricate d 80 mm high purity aluminum ingots. SEM and AFM were used to detect the shape of grain boundaries. The orientation of the grain was studied by X-ray diffractometry. The results show that the nucleation points locate at the intersections of three adjacent grains. The lattice orientation of grains does not alter in the horizontal direction, but gradually approaches the optimum growth direction in the vertical direction during the growth process. All the grains suffer the competition and only the one whose orientation is closest to the preferred direction can occupy the final growth space.
文摘In this study,low-field nuclear magnetic resonance(LF-NMR)was used to collect the transverse relaxation signals of camphor seeds that had been dried at different temperatures and for different durations.The transverse relaxation time of the hydrogen nucleus was obtained by SIRT(Simultaneous Iterative Reconstruction Technique)inversion,and the correlation between the moisture content on dry basis and the amplitude of NMR signal of camphor seeds sampled at different drying stages was analyzed.The results showed that water existed in three main forms strongly bound water,weakly bound water and free water in camphor seeds.During the drying process,the peak position of strongly bound water remained unchanged,but the peak positions of weakly bound water and free water fluctuated.Drying rate increased with drying temperature increasing.In addition,there was a very significant linear relationship between the total NMR signal amplitude and moisture content on dry basis,and the correlation coefficient reached 0.984 4.
基金This work was supported by National Priority Research and Development Program of China(2016YFD0600204)National Natural Science Foundation of China(41701264)+2 种基金Natural Science Foundation of Jiangsu Province,China(BK20170931)Natural Science Research Program(16KJB210005)Overseas Training Program and Priority Academic Program Development Funds(PAPD)of Jiangsu Higher Education Institutions.
文摘The priming effect(PE)induced by biochar provides a basis for evaluating its carbon(C)sequestration potential in soils.A 60 days’laboratory incubation was conducted,which involved the amendment of biochar(1%of soil mass)produced from rice straw at 300℃(B300)and 500℃(B500)to young(Y)and old(O)poplar plantation soils,with the aim of studying the responses of biochar-induced PEs to poplar plantation ages.This incubation included six treatments:Y+CK(control),Y+B300,Y+B500,O+CK,O+B300,and O+B500.Carbon dioxide(CO_(2))emissions were significantly increased(p<0.05)in the B300 amended soils,while it was decreased in the B500 amended soils compared to the CK.The primed CO_(2) emissions were 2.35 times higher in the Y+B300 than the O+B300 treatments,which was measured to be 18.6 and 5.56 mg C·kg^(-1) with relative PEs of 12.4%and 3.35%,respectively.However,there was little difference between the primed CO_(2) emissions in Y+B500 and O+B500 treatments,which were measured to be-24.9 and-29.6 mg·C·kg^(-1) with relative PEs of-16.6%and-17.8%,respectively.Dissolved organic carbon(DOC)was significantly lower in the young poplar plantation soil than that in the old poplar plantation soil regardless of biochar amendment throughout the incubation,indicating greater C-limit of soil microorganisms in the young poplar plantation soil.Using ^(13)C isotope tracing,neither B300 nor B500 decreased native soil-derived DOC,which indicated that the negative B500-induced PEs were not due to a reduction in the availability of native soil-derived C.In conclusion,the response of biochar-induced PEs to poplar plantation age depends on biochar types while soil available C indirectly affects biochar-induced PEs.Further studies should focus on how the interactive effects between soil C availability and microbial community impacts biochar-induced PEs.
基金Funded by the National Natural Science Foundation of China(51002126)the Opening Project of Material Corrosion and Protection Key Laboratory of Sichuan Province(2017CL20)
文摘Nickel oxalate micro-spheres with core-shell structure of solid core and radiate shell were synthesized by precipitation method in a mixed water solution, with oxalic acid and nickel acetate as raw materials, through dropping ammonium hydroxide to adjust the solution pH value to about 8.0. Nickel microspheres with core-shell structure of solid core and porous shell were prepared by decomposing of nickel oxalate microspheres precursor at about 340 ℃ in argon atmosphere. The analyses of infrared spectroscopy(IR)indicates that the composition of the powders is nickel oxalate. The analyses of atomic absorption spectrometry(AAS) and organic elemental analysis(OEA) indicate that the molar ratio of(C2O4)^2-/Ni^2+ is about 1.02, close to the theoretical value of 1.0. The results of the thermo-gravimetric and differential thermal gravity analyses(TG-DTG) indicate that the molar ratio of(C2O4)^2-/Ni^2+ is about 1.06, also close to the theoretical value of 1.0.The analysis of X-ray diffraction(XRD) indicates that the composition of black powders as-prepared is nickel,which has a face-centered cubic crystal structure with average crystal grain size about 16.87 nm. The images of scanning electron microscopy(SEM) indicate that the morphology of nickel oxalate microspheres is a coreshell structure with solid core and radiate shell. The diameter of nickel oxalate microspheres is about 3 μm, and the shell consists of a large number of thin nanorods. The images of SEM also indicate that the morphology of nickel microspheres is a core-shell structure with solid core and porous shell. The diameter of nickel microspheres is about 2 μm, and the shell consists of a large number of nickel grains, surface holes and through holes. The diameter of nickel grains is about 50-100 nm, and the diameter of holes is about 50-200 nm.
基金Supported by Guangxi Innovation Team Construction Project of National Modern Agricultural Industrial Technology System(nycytxgxcxtd-19)Guangxi Agricultural Science and Technology Self Financing Project(Z2022114)。
文摘Chinese herbal medicine additives can not only directly improve the growth performance of chickens,but also indirectly affect the growth of chickens by enhancing the antioxidant capacity,immunity and disease resistance of the body,and eliminating diseases and adverse factors,thereby improving the growth performance of chickens.In the context of the current national prohibition of adding antibiotics to feed,the research and application of Chinese herbal medicine additives are of practical significance to eliminate the long-term use of antibiotics as chicken feed additives and reduce the threat to the environment and human health.For this reason,the research related to the substitution of Chinese herbal medicine for antibiotics is made a brief introduction to provide a reference in research and production practice.
基金This study was supported by the National Key Research and Development Program of China(grant 2017YFB0306100)the Natural Science Foundation of Hunan Province(grant 2018JJ2524)the International scientific technological cooperation projects of China(grants 2015DFR50580 and 2013DFA31440).
文摘Highly dispersed gadolinium zirconate(GZ)nanoparticles with fluorite structure were successfully synthesized by co-precipitation method,and their phase composition and microstructure,formation mechanism,and grain growth kinetics were investigated.The results suggest that the nanoparticles were obtained through hydroxide dehydration and solid phase reaction.High dispersion was accomplished by ethanol solvent to reduce the hydrogen bond and sodium dodecyl benzene sulfonate(SDBS)surfactant to increase the electrostatic repulsion between the nanoparticles.The grain growth activation energy of GZ powders calcined at lower temperature(<1200°C)is 86.5 kJ/mol(Ql),and the grain growth activation energy of GZ powders calcined at higher temperature(>1200°C)is 148.4 kJ/mol(Qh).The current study shows that the optimal process to synthesize dispersed GZ nanoparticles includes ethanol solvent,3 wt.%SDBS surfactant,and 1100°C as calcining temperature.
基金Supported by the Natural Science Foundation of Shandong Province,China(No.ZR2012CM004)the National Natural Science Foundation of China(No.41506190)
文摘Little is known about the roles of dynorphin and Kappa opioid receptor(KOR) in mollusks. In this study, we aim to determine the distribution of dynorphin A and KOR-1 in the digestive system of the scallop Chlamys farreri. Using immunohistochemical staining, we confirmed the expression of dynorphin A and KOR-1 in the digestive system of C. farreri. Dynorphin A immunopositive cells were identified in intestine and hepatopancreas. In intestine, small and spherical dynorphin A immunopositive cells(4–9 μm in diameter) were scattered among the long columnar epithelial cells(ECs). In hepatopancreas, cells containing masses(5–14 μm in diameter) of dynorphin A immunopositive products were observed in epithelium of acinis. These immunopositive cells may be synthetic and/or secretory cells of dynorphin A. Dynorphin A immunoreactive products were commonly observed in epithelium and connective tissue(CT) of labial palps, mouth labia and stomach, which presented in forms of grains, fibers or flakes. KOR-1 immunoreactive material was observed in ECs and CTs of labial palps, mouth labia and stomach, intestine and hepatopancreas. The distribution of both dynorphin A and KOR-1 in the digestive organs suggests an involvement of dynorphin via KOR-1 in the functional regulation of the digestive system of C. farreri.
基金Project was supported by Union Analysis Testing Foundation of Zhong Guan Cun
文摘Non- focused ion beams may be employed to investigate the surface profile and the shape of microscopic objects or periodic surfaces by using the known stopping powers of ions in solids. The energy spectra of the scattered or reaction ions are recorded as a function of the angles between the beam, the object and the detector, and of the energy of incident ions. The shape parameters may then be determined using computer codes. Presented also are the typical experimental results.
基金National Natural Science Foundation of China (Nos.10275047,10575073)the Natural Science Foundation of Jiangsu Province of China (03KJB140116)
文摘Zn_(1-x)Cu_xO thin films were synthesized by the radio frequency (RF) magnetronsputtering technique using a ZnO target containing different pieces of small Cu-chips. X-raydiffraction (XRD) and scanning electron microscopy (SEM) were employed to analyze the crystallineand microstructure of the fihn, and X-ray photoelectron spectroscopy (XPS) was used toestablish the bonding characteristics and oxidation states of copper inside the ZnO host. Roomtemperature (RT) ferromagnetism was observed in the Zn_(1-x)Cu_xO films by a Quantum Designsuperconducting quantmn interference device (SQUID) and the saturation magnetic moment ofthe films was found to decrease with the increase in Cu content.
基金Funded by the State "Key Base Development Foudation" Project("973") of China(201CD610706)Natural Science Foundation of Jiangsu Province,China(2007191SB90098)+1 种基金Analysis and Testing Method Projext of Department of Natural Science Foundation of Jiangsu Provice, China (2006191TS90140)the Scientific Research Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry, China (2006191XLH0132)
文摘To identify the aggregates causing the alkali-silica reaction,and the reactivity of rocks in different parts of China,the mineral and texture characteristics of some typical coarse ag-gregates and the alkali reactivity of these aggregates were systematically investigated.On one hand,petrographic examination of aggregates,combined with X-ray diffraction analysis,chemical analysis,scanning electron microscopy,was conducted for analyzing their mineralogy and texture.It was found that not only mineral characteristics,but also their interior structure would affect their potential alkali-silica reactivity.Furthermore,the alkali-silica reactivity of aggregates is due to their mineral compositions,such as containing different alkali-reactive minerals,while,different stuc-tures of those aggregates with similar minerals affect their reactivity to some extent.There are some amount of micro-aperture and cracks across the quartz in the aggregate,which may become the natural accesses for Na+,K+,and OH-ions to intrude in the mortar or concrete during the process of alkali-silica reaction.Alkali-silica reactivity of the aggregates was detected by the accelerated mortar bars test.It was revealed that all the aggregates tested were alkali-silica reactive and the re-sults were also in accordance with their mineral and structure analysis.
基金supported by the National Natural Science Foundation of China(Grant No.10975099)the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning,China+2 种基金the Innovation Program of Shanghai Municipal Education Commission,China(GrantNo.13YZ072)the Shanghai Leading Discipline Project,China(Grant No.XTKX2012)the Innovation Fund Project for Graduate Students of Shanghai,China(Grant No.JWCXSL1302)
文摘A new concept, called the row–column visibility graph, is proposed to map two-dimensional landscapes to complex networks. A cluster coverage is introduced to describe the extensive property of node clusters on a Euclidean lattice. Graphs mapped from fractals generated with the probability redistribution model behave scale-free. They have pattern-induced hierarchical organizations and comparatively much more extensive structures. The scale-free exponent has a negative correlation with the Hurst exponent, however, there is no deterministic relation between them. Graphs for fractals generated with the midpoint displacement model are exponential networks. When the Hurst exponent is large enough(e.g., H >0.5), the degree distribution decays much more slowly, the average coverage becomes significant large, and the initially hierarchical structure at H < 0.5 is destroyed completely. Hence, the row–column visibility graph can be used to detect the pattern-related new characteristics of two-dimensional landscapes.
基金financially supported by the National Natural Science Foundation of China(No.21171020)
文摘Perovskite-type oxide has a general formula ABO_3. Both the lattice A- and lattice B-sites can be occupied by two kinds of metallic ions, forming substituted perovskites such as La_(1-x)Sr_xCoO_3-d and LaFe_xCo_(1-x)O_3. In the present work, we aim to investigate competitive occupying of Fe^(3+) and Co^(3+) ions into the lattice B-sites of perovskite LaFe_xCo_(1-x)O_3 formed under the condition of excess feeding of Fe^(3+) and Co^(2+) ions relative to the La^(3+) ions. For this purpose, standard curve of normalized cell volumes(NCVs) of a defined series of perovskites LaFe_xCo_(1-x)O_3 versus the x values was plotted. Lattice occupancy of Fe^(3+) ions at the B-sites of the perovskite LaFe_xCo_(1-x)O_3 was then determined from the standard curve. It is proved that Fe^(3+) ions were capable of occupying preferentially into the lattice B-sites of the perovskite crystalline structure.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51431009 and 51271038)the Joint NSFC-ISF Research Program+1 种基金Jointly Funded by the National Natural Science Foundation of Chinathe Israel Science Foundation(Grant No.51561145003)
文摘The structural, magnetic properties, and electronic structures of hexagonal Fe Co Sn compounds with as-annealed bulk and ribbon states were investigated by x-ray powder diffraction(XRD), differential scanning calorimetry(DSC), transmission electron microscope(TEM), scanning electron microscope(SEM), magnetic measurements, and first-principles calculations. Results indicate that both states of FeCoSn show an Ni_2In-type hexagonal structure with a small amount of FeCo-rich secondary phase. The Curie temperatures are located at 257 K and 229 K, respectively. The corresponding magnetizations are 2.57 μB/f.u. and 2.94 μB/f.u. at 5 K with a field of 50 kOe(1 Oe = 79.5775 A·m^(-1)). The orbital hybridizations between 3 d elements are analyzed from the distribution of density of states(DOS), showing that Fe atoms carry the main magnetic moments and determine the electronic structure around Fermi level. A peak of DOS at Fermi level accounts for the presence of the FeCo-rich secondary phase. The Ni_2In-type hexagonal FeCoSn compound can be used during the isostructural alloying for tuning phase transitions.
