Low-concentration coal mine methane(LC-CMM),which is predominantly composed of methane,serves as a clean and low-carbon energy resource with significant potential for utilization.Utilizing LC-CMM as fuel for solid oxi...Low-concentration coal mine methane(LC-CMM),which is predominantly composed of methane,serves as a clean and low-carbon energy resource with significant potential for utilization.Utilizing LC-CMM as fuel for solid oxide fuel cells(SOFCs)represents an efficient and promising strategy for its effective utilization.However,direct application in Ni-based anodes induces carbon deposition,which severely degrades cell performance.Herein,a medium-entropy oxide Sr_(2)FeNi_(0.1)Cr_(0.3)Mn_(0.3)Mo_(0.3)O_(6−δ)(SFNCMM)was developed as an anode internal reforming catalyst.Following reduction treatment,FeNi_(3) nano-alloy particles precipitate on the surface of the material,thereby significantly enhancing its catalytic activity for LC-CMM reforming process.The catalyst achieved a methane conversion rate of 53.3%,demonstrating excellent catalytic performance.Electrochemical evaluations revealed that SFNCMM-Gd_(0.1)Ce_(0.9)O_(2−δ)(GDC)with a weight ratio of 7:3 exhibited superior electrochemical performance when employed as the anodic catalytic layer.With H_(2) and LC-CMM as fuels,the single cell achieved maximum power densities of 1467.32 and 1116.97 mW·cm^(−2) at 800℃,respectively,with corresponding polarization impedances of 0.17 and 1.35Ω·cm^(2).Furthermore,the single cell maintained stable operation for over 100 h under LC-CMM fueling without significant carbon deposition,confirming its robust resistance to carbon formation.These results underscore the potential of medium-entropy oxides as highly effective catalytic layers for mitigating carbon deposition in SOFCs.展开更多
As classical cathode materials of solid oxide fuel cell(SOFC),Fe-based perovskite materials are favored for their affordable price,low thermal expansion coefficient and high stability.In this study,B-site high-entropy...As classical cathode materials of solid oxide fuel cell(SOFC),Fe-based perovskite materials are favored for their affordable price,low thermal expansion coefficient and high stability.In this study,B-site high-entropy perovskite oxide La_(0.7)Sr_(0.3)(FeNiCo)_(0.8)Mo_(0.1)Ti_(0.1)O_(3-δ)(LSFNCMT)was prepared by the citric acid-nitrate combustion method.Due to the faster oxygen surface exchange rate of the high-entropy material,the LSFNCMT cathode shows excellent oxygen reduction reaction(ORR)activity with a polarization impedance(Rp)of 0.11Ω·cm^(2) at 800℃,which is much lower than that of the La_(0.7)Sr_(0.3)FeO_(3-δ)(LSF)cathode(0.31Ω·cm^(2)).Furthermore,the high-entropy material exhibits superior stability due to incorporation of highly acidic Ni,Co,and Mo cations as well as Ti cation with more negative average bonding energy(ABE)of metal-oxygen.In the 22 h-stability test of the symmetric cell with LSFNCMT cathode in the Cr-containing atmosphere,Rp only increases from 1.07Ω·cm^(2) to 2.98Ω·cm^(2),while Rp of the LSF cathode increases from 2.62Ω·cm^(2) to 7.90Ω·cm^(2) under the same conditions,indicating better Cr-resistance of LSFNCMT due to the high-entropy strategy.The fact that the maximum power density(MPD)of the single cell with LSFNCMT cathode at 800℃is 1105.26 mW·cm^(-2),significantly higher than that of LSF cathode(830.74 mW·cm^(-2)),and Rp at 800℃is 0.24Ω·cm^(2),lower than that of LSF cathode(0.36Ω·cm^(2)),confirming excellent toxicity resistance of the high-entropy cathode.This study shows that B-position high entropy is an effective way to improve the catalytic activity and chromium resistance of cathode materials.展开更多
Financial market liquidity is a popular research topic.Investor-driven research uses the turnover rate to measure liquidity and generally finds that the higher the stock turnover rate,the lower the returns.However,the...Financial market liquidity is a popular research topic.Investor-driven research uses the turnover rate to measure liquidity and generally finds that the higher the stock turnover rate,the lower the returns.However,the traditional financial liquidity theory has been impacted by new machine-driven quantitative trading models.To explore high machine-driven liquidity and the impact of high turnover rates on returns,this study establishes a dual-market quantitative trading system,introduces a variational modal decomposition(VMD)-bidirectional gated recurrent unit(BiGRU)model for data prediction,and uses the back-end Hong Kong foreign exchange market to develop a quantitative trading strategy using the same rotating funds in the U.S.and Chinese stock markets.The experimental results show that given a principal amount of 210,000.00 CNY,the final predicted net return is 226,538.30 CNY,a net return of 107.86%,which is 40.6%higher than the net return of a single Chinese market.We conclude that,under machine-driven trading,increasing liquidity and turnover increase returns.This study provides a new perspective on liquidity theory that is useful for future financial market research and quantitative trading practices.展开更多
Thallium(Tl)compounds,highly toxic to biology,are usually released into flue gas during fossil/minerals combustion,and further distributed in water and soil.In this work,we fundamentally investigated the capture of ga...Thallium(Tl)compounds,highly toxic to biology,are usually released into flue gas during fossil/minerals combustion,and further distributed in water and soil.In this work,we fundamentally investigated the capture of gaseous Tl_(2)O by industrial V2O5-WO3/TiO_(2)catalyst under working condition in Tl-containing flue gas.Experimental and theoretical results indicated that the Tl_(2)O has significant electron-feeding capacity and easily donate electron to unoccupied orbitals of TiO_(2),leading to dismutation of Ti 2p and inartificial formation of p-n junction on TiO_(2)surface,which prompted Tl_(2)O selectively interacted with TiO_(2)in flue gas.Herein,we proposed and verified an effective way to capture gaseous Tl_(2)O,which offered almost the best choice to eliminate Tl emission from flue gas and expanded the function of the TiO_(2)-based catalyst.The formation of p-n junction on commercial V2O5-WO3/TiO_(2)catalyst under working condition was revealed for the first time,which can be a valuable reference for both heterocatalysis and electro/photocatalysis.展开更多
The ability to cancel a motor response is critical for optimal functioning in various facets of daily life. Hence, efficient inhibitory motor control is a key function throughout the lifespan. Considering the fact tha...The ability to cancel a motor response is critical for optimal functioning in various facets of daily life. Hence, efficient inhibitory motor control is a key function throughout the lifespan. Considering the fact that inhibitory motor function gradually declines with advancing age, it is not surprising that the study of motor inhibition in this age group is gaining considerable interest. In general, we can distinguish between two prominent types of motor inhibition, namely proactive and reactive inhibition. Whereas the anticipation for upcoming stops(proactive inhibition) appears readily preserved at older age, the ability to stop an already planned or initiated action(reactive inhibition) generally declines with advancing age. The differential impact of aging on proactive and reactive inhibition at the behavioral level prompts questions about the neural architecture underlying both types of inhibitory motor control. Here we will not only highlight the underlying structural brain properties of proactive and reactive inhibitory control but we will also discuss recent developments in brain-behavioral approaches, namely the registration of neurochemical compounds using magnetic resonance spectroscopy. This technique allows for the direct detection of the primary inhibitory neurotransmitter in the brain, i.e., γ-aminobutyric acid, across the broader cortical/subcortical territory, thereby opening new perspectives for better understanding the neural mechanisms mediating efficient inhibitory control in the context of healthy aging. Ultimately, these insights may contribute to the development of interventions specifically designed to counteract age-related declines in motor inhibition.展开更多
Construction underground pipes and underground culvertsarch (UCA) in order to transport the flow natural rivers and city’s sewage at the same time, is a practice that should be prohibited by the Mexico National Water...Construction underground pipes and underground culvertsarch (UCA) in order to transport the flow natural rivers and city’s sewage at the same time, is a practice that should be prohibited by the Mexico National Water Law (NWL). When UCA collapse, it causes severe damage to surrounding infrastructure, public and private property, and puts citizens’ lives at risk. This work presents some examples of UCA collapse incidents in several cities around the world, emphasizes how important preventive maintenance of these structures is, highlights the need to classify risk areas, and stresses the need to formulate norms and civil defense plans as article 83 of the NWL suggests. We also propose an addition to Fraction I, article 100 of the National Water Law, to protect the animal and plant life of its banks and safety of their natural runoff.展开更多
The effects of the post-deformation annealing on the microstructural evolution of hot rolled Al7075 matrix composites reinforced with CNTs and GNPs were investigated.The multi-pass hot rolling was applied on the stir ...The effects of the post-deformation annealing on the microstructural evolution of hot rolled Al7075 matrix composites reinforced with CNTs and GNPs were investigated.The multi-pass hot rolling was applied on the stir cast samples.Annealing was then applied to the composites at 450℃ for 4 h.Microstructural evolution was examined by SEM,EDS,and EBSD techniques.EBSD data showed that the addition of 0.87 vol.%(GNPs+CNTs)significantly inhibited the occurrence of recrystallization.Also,in the composite with 0.96 vol.%CNTs,recrystallization was partially inhibited.Whereas,in composites with 0.92 vol.%of GNPs,the occurrence of recrystallization through particle stimulated nucleation(PSN)mechanism was significantly accelerated.The volume fraction of recrystallized grains depends significantly on the occurrence of PSN in the presence of reinforcements.The intensity and type of the main components of the texture as well as the FCC fibers depend on the type of reinforcement.展开更多
Three different low-temperature plasma-based methods were used to improve the surface hydrophilicity of polyethy- lene （PE） films, and all the modification processes were carried out by employing an atmospheric pres...Three different low-temperature plasma-based methods were used to improve the surface hydrophilicity of polyethy- lene （PE） films, and all the modification processes were carried out by employing an atmospheric pressure plasma jet （APPJ） system. （a） PE films were directly modified by APPJ using a gas mixture of He and 02. （b） Acrylic acid （AA） was introduced into the system and a polymer acrylic acid （PAA） coating was deposited onto the PE films. （c） AA was grafted onto the PE surface activated by plasma pre-treatment. It was found that the hydrophilicity of the PE films was significantly improved for all the three methods. However, the samples modified by Process （a） showed hydrophobicity recovery after a storage time of 20 days while no significant change was found in samples modified by Process （b） and Process （c）. The Fourier transform infrared spectroscopy （FTIR） results indicated that the most intensive C=O peak was detected on the PE surface modified by Process （c）. According to the X-ray photoelectron spectroscopy （XPS） analysis, the ratios of oxygen-containing polar groups for samples modified by Process （b） and Process （c） were higher than that modified by Process （a）.展开更多
In this work,the thermodynamic,mechanical properties and electronic behaviors of D022-TiAl3 doped with W and 15 groupⅣM(M=C,Ge,Pb,Si and Sn)dopants are investigated by DFT methods.We established that ductility can be...In this work,the thermodynamic,mechanical properties and electronic behaviors of D022-TiAl3 doped with W and 15 groupⅣM(M=C,Ge,Pb,Si and Sn)dopants are investigated by DFT methods.We established that ductility can be improved using multi-doping approach and revealed the mechanisms behind such brittle-to-ductile transition.In addition,it is found that there is linearity between changes in Young’s modulus and tensile/compre s sive strain ratio.An alternate insight into brittle-to-ductile transition during ductile mode cutting of brittle materials is proposed.展开更多
In continental and oceanic conditions, clay-rich deposits are characterised by the development of polygonal fracture systems（PFS）. PFS can increase the vertical permeability of clay-rich deposits（mean permeability ...In continental and oceanic conditions, clay-rich deposits are characterised by the development of polygonal fracture systems（PFS）. PFS can increase the vertical permeability of clay-rich deposits（mean permeability ≤10-16 m2） and are pathways for fluids. On continents, the width of PFS ranges from centimeters to hundreds of meters, while in oceanic contexts they are up to a few kilometers large. These structures are linked to water-solid separation during deposition, consolidation and complete fluid squeeze of the clay horizon. During the last few decades, modeling of melt migration in partially molten plastic rocks led to rigorous quantifications of two-phase flows with a particular emphasis on 2D and 3D induced flow structures. The numerical modeling shows that the melt migrates on distances almost equal to a few times the compaction length L that depends on permeability and viscosity. Consequently, polygonal structures in partially molten plastic rocks are resulted from the melt-rock separation and their sizes are proportional to L. Applying these results to fluid-solid separation in clay-rich horizons, we show that（1） centimetric to kilometric PFS are resulted from the dramatic increase of L during compaction and（2）, this process involves agglomerates with 100 μm to 1 mm size.展开更多
The study was to investigate the effects of different thawing temperatures(5,15,40,75,90 ℃) and times(1- 120 s) on properties of post-thaw cow semen by detecting frozen-thawed semen motility,acrosome integrity and ta...The study was to investigate the effects of different thawing temperatures(5,15,40,75,90 ℃) and times(1- 120 s) on properties of post-thaw cow semen by detecting frozen-thawed semen motility,acrosome integrity and tail membrane integrity,further obtaining the optimal thawing method of straw frozen semen from dairy cow. The results showed that(1) Thawing of the straw frozen semen of dairy cow at 75 ℃ for 3 s yielded the highest semen motility,followed by 40 ℃for 20 s,and the least by low temperature 5 ℃ and room temperature 15 ℃ with a semen motility of 0. 3,moreover thawing at high temperature 90 ℃ was not suitable for large scale production due to the difficult control of the temperature;(2) The acrosome intact rate and plasma membrane integrity rate of semens thawed at90 ℃ were remarkably lower than that at 40 ℃ and 75 ℃ significantly(P 【 0. 05),while its semen malformation rate was significantly higher than that at 40 ℃and 75 ℃(P 【 0. 05);(3) The Survival time of semens at 37 ℃ varied largely among different thawing temperature,in detail by 40 ℃ 】 75 ℃ 】 90 ℃. In practice,the thawing method of straw frozen semen of dairy cow should be selected according to the specific circumstance and inseminated immediately,with the recommended condition of thawing at 75 ℃ for 3 s. If the thawed semen could not be inseminated immediately,the thawing should be performed at 20 s for 40 ℃to maintain the motility for a longer term.展开更多
Encapsulation of alkali metals （Li, Na, K, and Rb） into Zn12O12 nanocage has been inves- tigated using density functional theory. Encapsulation of Li and Na atoms is found to be thermodynamically favorable at 298 K ...Encapsulation of alkali metals （Li, Na, K, and Rb） into Zn12O12 nanocage has been inves- tigated using density functional theory. Encapsulation of Li and Na atoms is found to be thermodynamically favorable at 298 K and 100 kPa, with negative Gibbs free energy change AG of about -130.12 and -68.43 kJ/mol, respectively. By increasing the size of encapsu- lated atom the process become less favorable so that in the cases of K and Rb encapsulations the AG values are positive. The results indicate that the LUMO, Fermi level, and specially HOMO of the cluster are shifted to higher energies so that the HOMO-LUMO gap of the cluster is significantly narrowed in all the cases. After encapsulation of the alkali metals the work function of cluster is decreased due to the shift of the Fermi level to higher energies. Therefore, the emitted electron current density from the Zn12O12 cluster will be increased.展开更多
Membrane technology has become the mainstream process for the production of electronic grade hydrogen peroxide(H_(2)O_(2)).But due to the oxidation degradation of the organic membranes(e.g.polyamide)by the strong oxid...Membrane technology has become the mainstream process for the production of electronic grade hydrogen peroxide(H_(2)O_(2)).But due to the oxidation degradation of the organic membranes(e.g.polyamide)by the strong oxidative radicals(e.g.OH)generated via the activation of H_(2)O_(2)by iron ions(Fe^(3+)),the short effective lifetime of membranes remains a challenge.Inorganic nano tin oxide(SnO_(2))has great potential for the removal of Fe^(3+)in strongly oxidative H_(2)O_(2)because of its ability to stabilize H2O_(2)and preferentially adsorb Fe^(3+).Herein,we have designed for the first time a flower-like robust SnO_(2)membrane on the ceramic support by in situ template-free one-step hydrothermal method.The three-dimensional loose pore structure in the membrane built by interlacing SnO_(2)nanosheets endows the SnO_(2)membrane with a high specific surface area and abundant adsorption sites(AOH).Based on the coordination complexation and electrostatic attraction between the SnO_(2)surface and Fe^(3+),the membrane shows a high Fe3+removal efficiency(83%)and permeability(24 L·m^(-2)·h^(-1)·MPa^(-1))in H_(2)O_(2).This study provides an innovative and simple approach to designing robust SnO_(2)membranes for highly efficient removal of Fe^(3+)in harsh environments,such as strong oxidation conditions.展开更多
This work presents the hydrologic estimations of the hydraulic underground arched culvert channel (UACC) in Sabinal Basin, Chiapas, México and the hydrological problems associated with it, such as the erosion phe...This work presents the hydrologic estimations of the hydraulic underground arched culvert channel (UACC) in Sabinal Basin, Chiapas, México and the hydrological problems associated with it, such as the erosion phenomenon and abrasion cavity formation in it. On the other hand, the maximum flows that the UACC could transport were analyzed, concluding that it no longer has the hydraulic capacity to transport the flow rate associated to return periods equal to or greater than five years and that maximum permissible velocity UACC’s bottom is 3 m/s.展开更多
Acoustic cloak based on coordinate transformation is of great topical interest and has promise in potential appli- cations such as sound transparency and insulation. The frequency response of acoustic cloaks with a qu...Acoustic cloak based on coordinate transformation is of great topical interest and has promise in potential appli- cations such as sound transparency and insulation. The frequency response of acoustic cloaks with a quantity of discrete homogeneous layers is analyzed by the acoustic scattering theory. The effect of coordinate transforma- tion function on the acoustic total scattering cross section is discussed to achieve low scattering with only a few layers of anisotropic metamaterials. Also, the physics of acoustic wave interaction with the interfaces between the discrete layers inside the cloak shell is discussed. These results provide a better way of designing a multilayered acoustic cloak with fewer layers.展开更多
DNA fragments encoding the light chain and heavy chain genes of an anti-human HER II antibody, trastuzumab, fused with an egg-lysozyme signal peptide were synthesized based on the codon bias of the methylotrophic yeas...DNA fragments encoding the light chain and heavy chain genes of an anti-human HER II antibody, trastuzumab, fused with an egg-lysozyme signal peptide were synthesized based on the codon bias of the methylotrophic yeast Pichia pastoris. These fragments were inserted into a site between the AOX 1-promoter and -terminator in pPICZ A to be expressed by P. pastoris. The expression vector was linearized, and introduced into P. pastoris GS115 by electroporation. After the checking of several transformants with PCR to ensure a precise insertion, one was selected and cultured to examine antibody production. The level of production reached 10 mg/L in a flask with medium containing 1% methanol. The heavy chain and light chain of the product were assembled to form a hetero tetramer, as detected by dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). N-terminal amino acid sequencing revealed that the signal peptides of both chains were well processed. The mobility of the product in SDS-PAGE after treatment with Peptide N-Glycosidase F indicated the heavy chain to be N-glycosylated. Further analysis of the N-glycans with a mass spectrometer revealed a mixture of Man9-GlcNAc2, Man10-GlcNAc2, Man11-GlcNAc2 and Man12-GlcNAc2, but no hyper-mannosylated glycans. ELISA, surface plasmon resonance, and flow cytometric studies showed the affinity curve and Kd value for the antigen, HER II, and reactivity to a HER2-overexpressing breast cancer cell-line, SK-BR-3, to be almost the same as for the clinically used trastuzumab produced by CHO.展开更多
The aim of this study is to analyze the difficulties of reading and writing experienced by primary school pupils when writing a script for a theatrical performance called ＂digestion＂. Our main research questions are...The aim of this study is to analyze the difficulties of reading and writing experienced by primary school pupils when writing a script for a theatrical performance called ＂digestion＂. Our main research questions are： how does a theatrical performance help to reconsider the scripts and to build a model of the digestive system？ The pupils were encouraged to stage a theatrical performance for the whole school, explaining the digestion of a sandwich, a glass of water, an apple and a piece of chewing gum. The play helped to develop not only knowledge but also language. Having to produce a text for two different audiences, teachers and other learners led the students to debate between using ＂academic＂ vocabulary or more everyday vocabulary. Overall we found that they were more concerned with writing ＂academic＂ scripts, influenced by the texts that they consulted, than with writing a play accessible to all audiences.展开更多
This study was to investigate the effects of transport, storage temperature and time on parthenogenetical developmental competence of sheep oocyte. The ovaries were collected and randomly immersed in physiological sal...This study was to investigate the effects of transport, storage temperature and time on parthenogenetical developmental competence of sheep oocyte. The ovaries were collected and randomly immersed in physiological saline at （ 10 - 15 ） ℃, （20 - 25 ） ℃ and （30 - 35 ） ℃ and transported to the laboratory for culture. They were divided into three groups randomly in an optimized transport temperature, kept in physiological saline at4 ℃, （14 -18） ℃ and （25 -30） ℃ respectively; 15 - 17 h later, the ovaries were cutured for the maturation and parthenogenetic activation of oocytes. The results showed that the optimal transport temperature of ovaries was 20 -25 ℃, when the maturation rate and blastocysts rate reached 67.44% and 35.93% respectively. Incubating sheep ovaries at （ 14 - 18 ） ℃ for （15 -17） h did not reduce the maturation rate （61.81%） and blastocysts rate （29.03%） of oocyte significantly. However, incubating sheep ovaries at 4 ℃ or （25 -30） ℃ significantly reduced the maturation rate （41.90%, 18.40% ） and cleavage rate （9.09%, 13.04% ）, and the ovaries could not develop into blastocysts at these two temperature ranges. It can be concluded that the optimal transport temperature of the sheep ovaries is 20 - 25 ℃, and incubation at 14 - 18 ℃ overnight in vivo does not affect the developmental competence of oocytes.展开更多
基金supported by the National Key R&D Program of China(No.2024YFB4007501)the Natural Science Foundation of Jiangsu Province(No.BK20240109)the project of Jiangsu Key Laboratory for Clean Utilization of Carbon Resources(No.BM2024007).
文摘Low-concentration coal mine methane(LC-CMM),which is predominantly composed of methane,serves as a clean and low-carbon energy resource with significant potential for utilization.Utilizing LC-CMM as fuel for solid oxide fuel cells(SOFCs)represents an efficient and promising strategy for its effective utilization.However,direct application in Ni-based anodes induces carbon deposition,which severely degrades cell performance.Herein,a medium-entropy oxide Sr_(2)FeNi_(0.1)Cr_(0.3)Mn_(0.3)Mo_(0.3)O_(6−δ)(SFNCMM)was developed as an anode internal reforming catalyst.Following reduction treatment,FeNi_(3) nano-alloy particles precipitate on the surface of the material,thereby significantly enhancing its catalytic activity for LC-CMM reforming process.The catalyst achieved a methane conversion rate of 53.3%,demonstrating excellent catalytic performance.Electrochemical evaluations revealed that SFNCMM-Gd_(0.1)Ce_(0.9)O_(2−δ)(GDC)with a weight ratio of 7:3 exhibited superior electrochemical performance when employed as the anodic catalytic layer.With H_(2) and LC-CMM as fuels,the single cell achieved maximum power densities of 1467.32 and 1116.97 mW·cm^(−2) at 800℃,respectively,with corresponding polarization impedances of 0.17 and 1.35Ω·cm^(2).Furthermore,the single cell maintained stable operation for over 100 h under LC-CMM fueling without significant carbon deposition,confirming its robust resistance to carbon formation.These results underscore the potential of medium-entropy oxides as highly effective catalytic layers for mitigating carbon deposition in SOFCs.
基金Key-Area Research and Development Program of Guangdong Province(2022B0111130004)National Natural Science Foundation of China(52272257)。
文摘As classical cathode materials of solid oxide fuel cell(SOFC),Fe-based perovskite materials are favored for their affordable price,low thermal expansion coefficient and high stability.In this study,B-site high-entropy perovskite oxide La_(0.7)Sr_(0.3)(FeNiCo)_(0.8)Mo_(0.1)Ti_(0.1)O_(3-δ)(LSFNCMT)was prepared by the citric acid-nitrate combustion method.Due to the faster oxygen surface exchange rate of the high-entropy material,the LSFNCMT cathode shows excellent oxygen reduction reaction(ORR)activity with a polarization impedance(Rp)of 0.11Ω·cm^(2) at 800℃,which is much lower than that of the La_(0.7)Sr_(0.3)FeO_(3-δ)(LSF)cathode(0.31Ω·cm^(2)).Furthermore,the high-entropy material exhibits superior stability due to incorporation of highly acidic Ni,Co,and Mo cations as well as Ti cation with more negative average bonding energy(ABE)of metal-oxygen.In the 22 h-stability test of the symmetric cell with LSFNCMT cathode in the Cr-containing atmosphere,Rp only increases from 1.07Ω·cm^(2) to 2.98Ω·cm^(2),while Rp of the LSF cathode increases from 2.62Ω·cm^(2) to 7.90Ω·cm^(2) under the same conditions,indicating better Cr-resistance of LSFNCMT due to the high-entropy strategy.The fact that the maximum power density(MPD)of the single cell with LSFNCMT cathode at 800℃is 1105.26 mW·cm^(-2),significantly higher than that of LSF cathode(830.74 mW·cm^(-2)),and Rp at 800℃is 0.24Ω·cm^(2),lower than that of LSF cathode(0.36Ω·cm^(2)),confirming excellent toxicity resistance of the high-entropy cathode.This study shows that B-position high entropy is an effective way to improve the catalytic activity and chromium resistance of cathode materials.
基金supported by the National Natural Science Foundation of China(Grant Nos.:72032006 and 92146005).
文摘Financial market liquidity is a popular research topic.Investor-driven research uses the turnover rate to measure liquidity and generally finds that the higher the stock turnover rate,the lower the returns.However,the traditional financial liquidity theory has been impacted by new machine-driven quantitative trading models.To explore high machine-driven liquidity and the impact of high turnover rates on returns,this study establishes a dual-market quantitative trading system,introduces a variational modal decomposition(VMD)-bidirectional gated recurrent unit(BiGRU)model for data prediction,and uses the back-end Hong Kong foreign exchange market to develop a quantitative trading strategy using the same rotating funds in the U.S.and Chinese stock markets.The experimental results show that given a principal amount of 210,000.00 CNY,the final predicted net return is 226,538.30 CNY,a net return of 107.86%,which is 40.6%higher than the net return of a single Chinese market.We conclude that,under machine-driven trading,increasing liquidity and turnover increase returns.This study provides a new perspective on liquidity theory that is useful for future financial market research and quantitative trading practices.
基金financially supported by the National Natural Science Foundation of China(21936005,52070114 and 21876093)Tsinghua-Foshan Innovation Special Fund(TFISF).
文摘Thallium(Tl)compounds,highly toxic to biology,are usually released into flue gas during fossil/minerals combustion,and further distributed in water and soil.In this work,we fundamentally investigated the capture of gaseous Tl_(2)O by industrial V2O5-WO3/TiO_(2)catalyst under working condition in Tl-containing flue gas.Experimental and theoretical results indicated that the Tl_(2)O has significant electron-feeding capacity and easily donate electron to unoccupied orbitals of TiO_(2),leading to dismutation of Ti 2p and inartificial formation of p-n junction on TiO_(2)surface,which prompted Tl_(2)O selectively interacted with TiO_(2)in flue gas.Herein,we proposed and verified an effective way to capture gaseous Tl_(2)O,which offered almost the best choice to eliminate Tl emission from flue gas and expanded the function of the TiO_(2)-based catalyst.The formation of p-n junction on commercial V2O5-WO3/TiO_(2)catalyst under working condition was revealed for the first time,which can be a valuable reference for both heterocatalysis and electro/photocatalysis.
基金supported by the Research Foundation Flanders(G089818N to SPS)+6 种基金the Excellence of Science grant(EOS,30446199,MEMODYN to SPS)the KU Leuven Research Fund(C16/15/070 to SPS)the postdoctoral fellowship from the Research Fund KU Leuven(PDM/18/180 to LP)an aspirant fellowship of the Research Foundation–Flanders(FWO)to CM
文摘The ability to cancel a motor response is critical for optimal functioning in various facets of daily life. Hence, efficient inhibitory motor control is a key function throughout the lifespan. Considering the fact that inhibitory motor function gradually declines with advancing age, it is not surprising that the study of motor inhibition in this age group is gaining considerable interest. In general, we can distinguish between two prominent types of motor inhibition, namely proactive and reactive inhibition. Whereas the anticipation for upcoming stops(proactive inhibition) appears readily preserved at older age, the ability to stop an already planned or initiated action(reactive inhibition) generally declines with advancing age. The differential impact of aging on proactive and reactive inhibition at the behavioral level prompts questions about the neural architecture underlying both types of inhibitory motor control. Here we will not only highlight the underlying structural brain properties of proactive and reactive inhibitory control but we will also discuss recent developments in brain-behavioral approaches, namely the registration of neurochemical compounds using magnetic resonance spectroscopy. This technique allows for the direct detection of the primary inhibitory neurotransmitter in the brain, i.e., γ-aminobutyric acid, across the broader cortical/subcortical territory, thereby opening new perspectives for better understanding the neural mechanisms mediating efficient inhibitory control in the context of healthy aging. Ultimately, these insights may contribute to the development of interventions specifically designed to counteract age-related declines in motor inhibition.
文摘Construction underground pipes and underground culvertsarch (UCA) in order to transport the flow natural rivers and city’s sewage at the same time, is a practice that should be prohibited by the Mexico National Water Law (NWL). When UCA collapse, it causes severe damage to surrounding infrastructure, public and private property, and puts citizens’ lives at risk. This work presents some examples of UCA collapse incidents in several cities around the world, emphasizes how important preventive maintenance of these structures is, highlights the need to classify risk areas, and stresses the need to formulate norms and civil defense plans as article 83 of the NWL suggests. We also propose an addition to Fraction I, article 100 of the National Water Law, to protect the animal and plant life of its banks and safety of their natural runoff.
基金the Sahand University of Technology and Ghent University for the support of this research。
文摘The effects of the post-deformation annealing on the microstructural evolution of hot rolled Al7075 matrix composites reinforced with CNTs and GNPs were investigated.The multi-pass hot rolling was applied on the stir cast samples.Annealing was then applied to the composites at 450℃ for 4 h.Microstructural evolution was examined by SEM,EDS,and EBSD techniques.EBSD data showed that the addition of 0.87 vol.%(GNPs+CNTs)significantly inhibited the occurrence of recrystallization.Also,in the composite with 0.96 vol.%CNTs,recrystallization was partially inhibited.Whereas,in composites with 0.92 vol.%of GNPs,the occurrence of recrystallization through particle stimulated nucleation(PSN)mechanism was significantly accelerated.The volume fraction of recrystallized grains depends significantly on the occurrence of PSN in the presence of reinforcements.The intensity and type of the main components of the texture as well as the FCC fibers depend on the type of reinforcement.
基金Project supported by the National Natural Science Foundation of China(Grant No.11175157)the Zhejiang Provincial Key Innovation Team,China(Grant No.2012R10038)the 521 Talent Project of Zhejiang Sci-Tech University,China
文摘Three different low-temperature plasma-based methods were used to improve the surface hydrophilicity of polyethy- lene （PE） films, and all the modification processes were carried out by employing an atmospheric pressure plasma jet （APPJ） system. （a） PE films were directly modified by APPJ using a gas mixture of He and 02. （b） Acrylic acid （AA） was introduced into the system and a polymer acrylic acid （PAA） coating was deposited onto the PE films. （c） AA was grafted onto the PE surface activated by plasma pre-treatment. It was found that the hydrophilicity of the PE films was significantly improved for all the three methods. However, the samples modified by Process （a） showed hydrophobicity recovery after a storage time of 20 days while no significant change was found in samples modified by Process （b） and Process （c）. The Fourier transform infrared spectroscopy （FTIR） results indicated that the most intensive C=O peak was detected on the PE surface modified by Process （c）. According to the X-ray photoelectron spectroscopy （XPS） analysis, the ratios of oxygen-containing polar groups for samples modified by Process （b） and Process （c） were higher than that modified by Process （a）.
基金partially supported by the National Research Foundation,Prime Minister’s Office,Singapore under its Marine Science Research and Development program(Award No.MSRDPP28)the Ministry of Education,Singapore under Tier 2 program(Award No.MOE2018-T2-1-163)。
文摘In this work,the thermodynamic,mechanical properties and electronic behaviors of D022-TiAl3 doped with W and 15 groupⅣM(M=C,Ge,Pb,Si and Sn)dopants are investigated by DFT methods.We established that ductility can be improved using multi-doping approach and revealed the mechanisms behind such brittle-to-ductile transition.In addition,it is found that there is linearity between changes in Young’s modulus and tensile/compre s sive strain ratio.An alternate insight into brittle-to-ductile transition during ductile mode cutting of brittle materials is proposed.
基金support by the French Space Agency CNES,PNP(Programme National de Planétologie)TOSCA(Terre,Océan,Surfaces Continentales,Atmosphère)
文摘In continental and oceanic conditions, clay-rich deposits are characterised by the development of polygonal fracture systems（PFS）. PFS can increase the vertical permeability of clay-rich deposits（mean permeability ≤10-16 m2） and are pathways for fluids. On continents, the width of PFS ranges from centimeters to hundreds of meters, while in oceanic contexts they are up to a few kilometers large. These structures are linked to water-solid separation during deposition, consolidation and complete fluid squeeze of the clay horizon. During the last few decades, modeling of melt migration in partially molten plastic rocks led to rigorous quantifications of two-phase flows with a particular emphasis on 2D and 3D induced flow structures. The numerical modeling shows that the melt migrates on distances almost equal to a few times the compaction length L that depends on permeability and viscosity. Consequently, polygonal structures in partially molten plastic rocks are resulted from the melt-rock separation and their sizes are proportional to L. Applying these results to fluid-solid separation in clay-rich horizons, we show that（1） centimetric to kilometric PFS are resulted from the dramatic increase of L during compaction and（2）, this process involves agglomerates with 100 μm to 1 mm size.
基金Supported by the Technical Development and Demonstration Program of Beijing Vocational College of Agriculture(XY-YF-14-20)Agricultural S&T Program from Beijing Municipal Agricultural Commission(20140146)Non-staple Food Project from Beijing Municipal Agricultural Commission(20140204-7)
文摘The study was to investigate the effects of different thawing temperatures(5,15,40,75,90 ℃) and times(1- 120 s) on properties of post-thaw cow semen by detecting frozen-thawed semen motility,acrosome integrity and tail membrane integrity,further obtaining the optimal thawing method of straw frozen semen from dairy cow. The results showed that(1) Thawing of the straw frozen semen of dairy cow at 75 ℃ for 3 s yielded the highest semen motility,followed by 40 ℃for 20 s,and the least by low temperature 5 ℃ and room temperature 15 ℃ with a semen motility of 0. 3,moreover thawing at high temperature 90 ℃ was not suitable for large scale production due to the difficult control of the temperature;(2) The acrosome intact rate and plasma membrane integrity rate of semens thawed at90 ℃ were remarkably lower than that at 40 ℃ and 75 ℃ significantly(P 【 0. 05),while its semen malformation rate was significantly higher than that at 40 ℃and 75 ℃(P 【 0. 05);(3) The Survival time of semens at 37 ℃ varied largely among different thawing temperature,in detail by 40 ℃ 】 75 ℃ 】 90 ℃. In practice,the thawing method of straw frozen semen of dairy cow should be selected according to the specific circumstance and inseminated immediately,with the recommended condition of thawing at 75 ℃ for 3 s. If the thawed semen could not be inseminated immediately,the thawing should be performed at 20 s for 40 ℃to maintain the motility for a longer term.
文摘Encapsulation of alkali metals （Li, Na, K, and Rb） into Zn12O12 nanocage has been inves- tigated using density functional theory. Encapsulation of Li and Na atoms is found to be thermodynamically favorable at 298 K and 100 kPa, with negative Gibbs free energy change AG of about -130.12 and -68.43 kJ/mol, respectively. By increasing the size of encapsu- lated atom the process become less favorable so that in the cases of K and Rb encapsulations the AG values are positive. The results indicate that the LUMO, Fermi level, and specially HOMO of the cluster are shifted to higher energies so that the HOMO-LUMO gap of the cluster is significantly narrowed in all the cases. After encapsulation of the alkali metals the work function of cluster is decreased due to the shift of the Fermi level to higher energies. Therefore, the emitted electron current density from the Zn12O12 cluster will be increased.
基金support from the National Key Research and Development Program(2021YFB3801303)the National Natural Science Foundation of China(21838005,21921006)+1 种基金the State Key Laboratory of Materials-Oriented Chemical Engineering(SKL-MCE-22A03)the Key Research and Development Program of Jiangsu Provincial Department of Science and Technology(BE2022033-3).
文摘Membrane technology has become the mainstream process for the production of electronic grade hydrogen peroxide(H_(2)O_(2)).But due to the oxidation degradation of the organic membranes(e.g.polyamide)by the strong oxidative radicals(e.g.OH)generated via the activation of H_(2)O_(2)by iron ions(Fe^(3+)),the short effective lifetime of membranes remains a challenge.Inorganic nano tin oxide(SnO_(2))has great potential for the removal of Fe^(3+)in strongly oxidative H_(2)O_(2)because of its ability to stabilize H2O_(2)and preferentially adsorb Fe^(3+).Herein,we have designed for the first time a flower-like robust SnO_(2)membrane on the ceramic support by in situ template-free one-step hydrothermal method.The three-dimensional loose pore structure in the membrane built by interlacing SnO_(2)nanosheets endows the SnO_(2)membrane with a high specific surface area and abundant adsorption sites(AOH).Based on the coordination complexation and electrostatic attraction between the SnO_(2)surface and Fe^(3+),the membrane shows a high Fe3+removal efficiency(83%)and permeability(24 L·m^(-2)·h^(-1)·MPa^(-1))in H_(2)O_(2).This study provides an innovative and simple approach to designing robust SnO_(2)membranes for highly efficient removal of Fe^(3+)in harsh environments,such as strong oxidation conditions.
文摘This work presents the hydrologic estimations of the hydraulic underground arched culvert channel (UACC) in Sabinal Basin, Chiapas, México and the hydrological problems associated with it, such as the erosion phenomenon and abrasion cavity formation in it. On the other hand, the maximum flows that the UACC could transport were analyzed, concluding that it no longer has the hydraulic capacity to transport the flow rate associated to return periods equal to or greater than five years and that maximum permissible velocity UACC’s bottom is 3 m/s.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11004250 and 51275519.
文摘Acoustic cloak based on coordinate transformation is of great topical interest and has promise in potential appli- cations such as sound transparency and insulation. The frequency response of acoustic cloaks with a quantity of discrete homogeneous layers is analyzed by the acoustic scattering theory. The effect of coordinate transforma- tion function on the acoustic total scattering cross section is discussed to achieve low scattering with only a few layers of anisotropic metamaterials. Also, the physics of acoustic wave interaction with the interfaces between the discrete layers inside the cloak shell is discussed. These results provide a better way of designing a multilayered acoustic cloak with fewer layers.
文摘DNA fragments encoding the light chain and heavy chain genes of an anti-human HER II antibody, trastuzumab, fused with an egg-lysozyme signal peptide were synthesized based on the codon bias of the methylotrophic yeast Pichia pastoris. These fragments were inserted into a site between the AOX 1-promoter and -terminator in pPICZ A to be expressed by P. pastoris. The expression vector was linearized, and introduced into P. pastoris GS115 by electroporation. After the checking of several transformants with PCR to ensure a precise insertion, one was selected and cultured to examine antibody production. The level of production reached 10 mg/L in a flask with medium containing 1% methanol. The heavy chain and light chain of the product were assembled to form a hetero tetramer, as detected by dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). N-terminal amino acid sequencing revealed that the signal peptides of both chains were well processed. The mobility of the product in SDS-PAGE after treatment with Peptide N-Glycosidase F indicated the heavy chain to be N-glycosylated. Further analysis of the N-glycans with a mass spectrometer revealed a mixture of Man9-GlcNAc2, Man10-GlcNAc2, Man11-GlcNAc2 and Man12-GlcNAc2, but no hyper-mannosylated glycans. ELISA, surface plasmon resonance, and flow cytometric studies showed the affinity curve and Kd value for the antigen, HER II, and reactivity to a HER2-overexpressing breast cancer cell-line, SK-BR-3, to be almost the same as for the clinically used trastuzumab produced by CHO.
文摘The aim of this study is to analyze the difficulties of reading and writing experienced by primary school pupils when writing a script for a theatrical performance called ＂digestion＂. Our main research questions are： how does a theatrical performance help to reconsider the scripts and to build a model of the digestive system？ The pupils were encouraged to stage a theatrical performance for the whole school, explaining the digestion of a sandwich, a glass of water, an apple and a piece of chewing gum. The play helped to develop not only knowledge but also language. Having to produce a text for two different audiences, teachers and other learners led the students to debate between using ＂academic＂ vocabulary or more everyday vocabulary. Overall we found that they were more concerned with writing ＂academic＂ scripts, influenced by the texts that they consulted, than with writing a play accessible to all audiences.
基金Supported by Construction of Natural Science and Technology Platform in China(2005DKA21101)"863"Program(2006AA10Z198)Technical Development and Demonstration Program of Beijing Vocational College of Agriculture(XY-YF-14-20)
文摘This study was to investigate the effects of transport, storage temperature and time on parthenogenetical developmental competence of sheep oocyte. The ovaries were collected and randomly immersed in physiological saline at （ 10 - 15 ） ℃, （20 - 25 ） ℃ and （30 - 35 ） ℃ and transported to the laboratory for culture. They were divided into three groups randomly in an optimized transport temperature, kept in physiological saline at4 ℃, （14 -18） ℃ and （25 -30） ℃ respectively; 15 - 17 h later, the ovaries were cutured for the maturation and parthenogenetic activation of oocytes. The results showed that the optimal transport temperature of ovaries was 20 -25 ℃, when the maturation rate and blastocysts rate reached 67.44% and 35.93% respectively. Incubating sheep ovaries at （ 14 - 18 ） ℃ for （15 -17） h did not reduce the maturation rate （61.81%） and blastocysts rate （29.03%） of oocyte significantly. However, incubating sheep ovaries at 4 ℃ or （25 -30） ℃ significantly reduced the maturation rate （41.90%, 18.40% ） and cleavage rate （9.09%, 13.04% ）, and the ovaries could not develop into blastocysts at these two temperature ranges. It can be concluded that the optimal transport temperature of the sheep ovaries is 20 - 25 ℃, and incubation at 14 - 18 ℃ overnight in vivo does not affect the developmental competence of oocytes.
