Nano-computed tomography(Nano-CT)is an emerging,high-resolution imaging technique.However,due to their low-light properties,tabletop Nano-CT has to be scanned under long exposure conditions,which the scanning process ...Nano-computed tomography(Nano-CT)is an emerging,high-resolution imaging technique.However,due to their low-light properties,tabletop Nano-CT has to be scanned under long exposure conditions,which the scanning process is time-consuming.For 3D reconstruction data,this paper proposed a lightweight 3D noise reduction method for desktop-level Nano-CT called AAD-ResNet(Axial Attention DeNoise ResNet).The network is framed by theU-net structure.The encoder and decoder are incorporated with the proposed 3D axial attention mechanism and residual dense block.Each layer of the residual dense block can directly access the features of the previous layer,which reduces the redundancy of parameters and improves the efficiency of network training.The 3D axial attention mechanism enhances the correlation between 3D information in the training process and captures the long-distance dependence.It can improve the noise reduction effect and avoid the loss of image structure details.Experimental results show that the network can effectively improve the image quality of a 0.1-s exposure scan to a level close to a 3-s exposure,significantly shortening the sample scanning time.展开更多
Energetic Semiconductor bridge(ESCB)based on reactive multilayered films(RMFs)has a promising application in the miniature and intelligence of initiator and pyrotechnics device.Understanding the ignition enhancement m...Energetic Semiconductor bridge(ESCB)based on reactive multilayered films(RMFs)has a promising application in the miniature and intelligence of initiator and pyrotechnics device.Understanding the ignition enhancement mechanism of RMFs on semiconductor bridge(SCB)during the ignition process is crucial for the engineering and practical application of advanced initiator and pyrotechnics devices.In this study,a one-dimensional(1D)gas-solid two-phase flow ignition model was established to study the ignition process of ESCB to charge particles based on the reactivity of Al/MoO_(3) RMFs.In order to fully consider the coupled exothermic between the RMFs and the SCB plasma during the ignition process,the heat release of chemical reaction in RMFs was used as an internal heat source in this model.It is found that the exothermal reaction in RMFs improved the ignition performance of SCB.In the process of plasma rapid condensation with heat release,the product of RMFs enhanced the heat transfer process between the gas phase and the solid charge particle,which accelerated the expansion of hot plasma,and heated the solid charge particle as well as gas phase region with low temperature.In addition,it made up for pressure loss in the gas phase.During the plasma dissipation process,the exothermal chemical reaction in RMFs acted as the main heating source to heat the charge particle,making the surface temperature of the charge particle,gas pressure,and gas temperature rise continuously.This result may yield significant advantages in providing a universal ignition model for miniaturized ignition devices.展开更多
The development of aqueous battery with dual mechanisms is now arousing more and more interest.The dual mechanisms of Zn^(2+)(de)intercalation and I^(-)/I_(2)redox bring unexpected effects.Herein,differing from previo...The development of aqueous battery with dual mechanisms is now arousing more and more interest.The dual mechanisms of Zn^(2+)(de)intercalation and I^(-)/I_(2)redox bring unexpected effects.Herein,differing from previous studies using Zn I_(2)additive,this work designs an aqueous Bi I_(3)-Zn battery with selfsupplied I^(-).Ex situ tests reveal the conversion of Bi I_(3)into Bi(discharge)and Bi OI(charge)at the 1st cycle and the dissolved I^(-)in electrolyte.The active I^(-)species enhances the specific capacity and discharge medium voltage of electrode as well as improves the generation of Zn dendrite and by-product.Furthermore,the porous hard carbon is introduced to enhance the electronic/ionic conductivity and adsorb iodine species,proven by experimental and theoretical studies.Accordingly,the well-designed Bi I_(3)-Zn battery delivers a high reversible capacity of 182 m A h g^(-1)at 0.2 A g^(-1),an excellent rate capability with 88 m A h g^(-1)at 10 A g^(-1),and an impressive cyclability with 63%capacity retention over 20 K cycles at 10 A g^(-1).An excellent electrochemical performance is obtained even at a high mass loading of 6 mg cm^(-2).Moreover,a flexible quasi-solid-state Bi I_(3)-Zn battery exhibits satisfactory battery performances.This work provides a new idea for designing high-performance aqueous battery with dual mechanisms.展开更多
Catastrophic geological disasters frequently occur on slopes with obliquely inclined bedding structures(also referred to as obliquely inclined bedding slopes),where the apparent dip sliding is not readily visible.This...Catastrophic geological disasters frequently occur on slopes with obliquely inclined bedding structures(also referred to as obliquely inclined bedding slopes),where the apparent dip sliding is not readily visible.This phenomenon has become a focal point in landslide research.Yet,there is a lack of studies on the failure modes and mechanisms of hidden,steep obliquely inclined bedding slopes.This study investigated the Shanyang landslide in Shaanxi Province,China.Using field investigations,laboratory tests of geotechnical parameters,and the 3DEC software,this study developed a numerical model of the landslide to analyze the failure process of such slopes.The findings indicate that the Shanyang landslide primarily crept along a weak interlayer under the action of gravity.The landslide,initially following a dip angle with the support of a stable inclined rock mass,shifted direction under the influence of argillization in the weak interlayer,moving towards the apparent dip angle.The slide resistance effect of the karstic dissolution zone was increasingly significant during this process,with lateral friction being the primary resistance force.A reduction in the lateral friction due to karstic dissolution made the apparent dip sliding characteristics of the Shanyang landslide more pronounced.Notably,deformations such as bending and uplift at the slope’s foot suggest that the main slide resistance shifts from lateral friction within the karstic dissolution zone to the slope foot’s resistance force,leading to the eventual buckling failure of the landslide.This study unveils a novel failure mode of apparent dip creep-buckling in the Shanyang landslide,highlighting the critical role of lateral friction from the karstic dissolution zone in its failure mechanism.These insights offer a valuable reference for mitigating risks and preventing disasters related to obliquely inclined bedding landslides.展开更多
Objective: To investigate the effects of Yanghe Pingchuan Granules on airway remodeling in asthmatic rats, and to explore the mechanism of Interleukin-6/Janus kinase 2/ Signal transducing activator of transcription 3(...Objective: To investigate the effects of Yanghe Pingchuan Granules on airway remodeling in asthmatic rats, and to explore the mechanism of Interleukin-6/Janus kinase 2/ Signal transducing activator of transcription 3(IL-6/JAK2/STAT3) signal axis. Methods: We separated 42 healthy male SD rats into two groups, a control group (7) and a model group (35).The model group was sensitized with a combination of ovalbumin (OVA) and aluminum hydroxide for 2 weeks, while the control group was given an equal amount of physiological saline.After 2 weeks, the modeling group was randomly divided into Model group, Yanghe Pingchuan Granules high, medium and low dose groups and Dexamethasone group, each group consisted of 7 animals. After 4 weeks, OVA atomization and gavage were used for stimulation and treatment. Yanghe Pingchuan Granules high, middle and low groups were given 15.48, 7.74, 3.87 g∙kg-1 Yanghe Pingchuan Granules daily, dexamethasone group was given 0.0625 mg∙kg-1 dexamethasone daily, and the other groups were given the same amount of normal saline. HE, PAS and Masson staining were used to observe the lung histopathological changes in rats. The levels of interleukin-6, IL-23 and IL-17A were detected by ELISA. The expression levels of JAK-2, P-JAK2, STAT3 and P-STAT3 in lung tissues were detected by Western blot. Real-time quantitative polymerase chain reaction (qRT-PCR) was used to detect the mRNA expression levels of IL-6, JAK2 and STAT3 in rat lung tissue. Results: The lung tissue structure of the model group was severely damaged compared to the control group, accompanied by a great many of inflammatory cell infiltration, goblet cell hyperplasia, subepithelial collagen fiber deposition and airway epithelial thickening were more obvious. The expressions of IL-6, IL- 23 and IL-17A in serum were significantly increased (P<0.01), the protein expression levels of JAK-2, P-JAK2, STAT3 and P-STAT3 and the mRNA expression levels of IL-6, JAK2 and STAT3 in lung tissue were significantly increased (P<0.01);Compared with the model group, inflammatory cell infiltration, goblet cell proliferation, subepithelial collagen fiber deposition and airway epithelial thickening were significantly reduced in each administration group, and the expressions of IL-6, IL-23 and IL-17A in serum were significantly decreased (P< 0.01). The protein expression levels of JAK-2, P-JAK2, STAT3 and P-STAT3 and mRNA expression levels of IL-6, JAK2 and STAT3 in lung tissue were significantly decreased (P<0.01). Conclusion: Yanghe Pingchuan Granules can significantly alleviate airway remodeling in asthmatic rats, and its mechanism may be through inhibiting the IL-6/JAK2/STAT3 signal axis.展开更多
The microstructure, mechanical properties and fracture behavior of sand-cast Mg-10Gd-3Y-0.5Zr alloy （mass fraction,%） under T6 condition （air cooling after solid solution and then aging heat treatment） were invest...The microstructure, mechanical properties and fracture behavior of sand-cast Mg-10Gd-3Y-0.5Zr alloy （mass fraction,%） under T6 condition （air cooling after solid solution and then aging heat treatment） were investigated. The optimum T6 heat treatments for sand-cast Mg-10Gd-3Y-0.5Zr alloy are （525 ℃, 12 h＋225 ℃, 14 h） and （525 ℃, 12 h＋250 ℃, 12 h） according to age hardening curve and mechanical properties, respectively. The ultimate tensile strength, yield strength and elongation of the Mg-10Gd-3Y-0.5Zr alloy treated by the two optimum T6 processes are 339.9 MPa, 251.6 MPa, 1.5%and 359.6 MPa, 247.3 MPa, 2.7%, respectively. The tensile fracture mode of peak-aged Mg-10Gd-3Y-0.5Zr alloy is transgranular quasi-cleavage fracture.展开更多
Al-3B master alloy is a kind of efficient grain refiner for hypoeutectic Al-Si alloys. Experiments were carried out to evaluate the effect of undissolved AlB2 particles in Al-3B master alloy on the grain refinement of...Al-3B master alloy is a kind of efficient grain refiner for hypoeutectic Al-Si alloys. Experiments were carried out to evaluate the effect of undissolved AlB2 particles in Al-3B master alloy on the grain refinement of Al-7Si. It is found that the number and the settlement of AlB2 particles in the melt all have effect on the grain refining efficiency. On the basis of experiments and theoretical analysis, a new grain refinement mechanism was proposed to explain the grain refinement action of Al-3B on hypoeutectic Al-Si alloys. The formation of ＇Al-AlB2＇ shell structure is the direct reason for grain refinement and the undissolved AlB2 particles is the indirect nucleating base for subsequent α（Al） phase.展开更多
In order to improve the destruction efficiency of dioxins and also for developing new dioxin control technology, the destruction mechanisms of 2,3,7,8-tetrachlorodihenzo-p-dioxin （2,3,7,8-TCDD） by O3 and NO3, were i...In order to improve the destruction efficiency of dioxins and also for developing new dioxin control technology, the destruction mechanisms of 2,3,7,8-tetrachlorodihenzo-p-dioxin （2,3,7,8-TCDD） by O3 and NO3, were investigated employing quantum chemical calculations. For involved reactions, the microcosmic reaction processes were analyzed and depicted in detail based on geometry optimizations made by the B3LYP/6-31G（d） method. At the same time, the reaction activation energies were also calculated at the MP2/6- 311G（d,p）//B3LYP/6-31G（d） level. Configuration analysis indicated that 2,3,7,8-TCDD could be destroyed by 03 and NO3 in two different ways. The destruction of 2,3,7,8-TCDD by 03 proceeded via the addition of 03 and the cleavage of C=C while the destruction of 2,3,7,8-TCDD by NO3 proceeded via the substitution of chlorine by NO3. Calculated results show that, the activation energy of the destruction reaction of 2,3,7,8-TCDD by NO3 （267.48 kJ/mol） is much larger than that of the destruction reaction of 2,3,7,8-TCDD by O3 （51.20 kJ/mol）. This indicated that the destruction of 2,3,7,8-TCDD by 03 is much more efficient than that of 2,3,7,8-TCDD by NO3. The reason why the activation energy for the destruction reaction of 2,3,7,8-TCDD by NO3 is so large, is also discussed.展开更多
One kind of movable-pair analysis method is adopted to analyze the configuration of a 3-7R （revolute-pair） parallel decoupling mechanism, and the mechanism＇s characteristics are summarized. The mechanism has three ...One kind of movable-pair analysis method is adopted to analyze the configuration of a 3-7R （revolute-pair） parallel decoupling mechanism, and the mechanism＇s characteristics are summarized. The mechanism has three orthogonal distributional branch-chains, and all movable pairs are rotational joints. The movable platform of the mechanism has x, y, z translational decoupling directions. Furthermore, in order to verify the mechanism＇s decoupling characteristics, the mechanism＇s kinematics analysis is solved, and the mechanism＇s direct/inverse kinematics model, input/output velocities and accelerations are deduced, which confirm its decoupling movement characteristics. Finally, one kind of mechanism link decomposed-integrated approach is adopted, and the mechanism＇s dynamics model is completed with the Lagrange method, which also proves its decoupling force characteristics. All of these works provide significant theory for the further study of the mechanism＇s control strategy, design, path planning etc.展开更多
In order to explore the effect mechanism of solvent on the synthesis of the metal organic framework materials, the microscopic interaction between solvent and framework and the effects of N,N-dimethyl-formamide(DMF) o...In order to explore the effect mechanism of solvent on the synthesis of the metal organic framework materials, the microscopic interaction between solvent and framework and the effects of N,N-dimethyl-formamide(DMF) or N-methyl- 2-pyrrolidone(NMP) on solvothermal synthesis of [Zn4O(BDC)3]8 were investigated through a combined DFT and experimental study. XRD and SEM showed that the absorbability of NMP in the pore of [Zn4O(BDC)3]8 was weaker than that of DMF. The thermal decomposition temperature of [Zn4O(BDC)3]8 synthesized in DMF was higher than that in NMP according to TG and FT-IR. In addition, the nitrogen sorption isotherms indicated that NMP improved gas sorption property of [Zn4O(BDC)3]8. The COSMO optimized calculations indicated that the total energy of Zn4O(BDC)3 in NMP was higher than that in DMF, and compared with non-solvent system, the charge of zinc atoms decreased and the charge value was the smallest in NMP. Furthermore, the interaction of DMF, NMP or DEF in [Zn4O(BDC)3]8 crystal model was calculated by DFT method. The results suggested that NMP should be easier to be removed from pore of materials than DMF from the point of view of energy state. It can be concluded that NMP was a favorable solvent to synthesize [Zn4O(BDC)3]8 and the microscopic mechanism was that the binding force between Zn4O(BDC)3 and NMP molecule was weaker than DMF.展开更多
Electrochemical behavior of layered LiNi0.5Mn0.5O2 in LiNO3 aqueous solution and its cyclic fading mechanism in electrolytes with different pH values were investigated. CV results show that LiNi0.5Mn0.5O2 has good ele...Electrochemical behavior of layered LiNi0.5Mn0.5O2 in LiNO3 aqueous solution and its cyclic fading mechanism in electrolytes with different pH values were investigated. CV results show that LiNi0.5Mn0.5O2 has good electrochemical reversible behaviors in 5 mol/L LiNO3 solution. Meanwhile, the electrode in 5 mol/L LiNO3 with pH value of 12 demonstrates the best electrochemical stability. Based on the electrochemical impedance spectroscopy （EIS）, X-ray diffraction （XRD） and scanning electron microscopy （SEM） results, it is proposed that suppressed charge-transfer resistance is the major reason, which is probably ascribed to the more stable electrode surface and less structure change.展开更多
Influence of multi-cycle cryogenic treatment and tensile temperature on microstructure, mechanical properties and fracture mechanism of as-extruded Mg-10Gd-3Y-0.5Zr magnesium alloy was investigated. The results show t...Influence of multi-cycle cryogenic treatment and tensile temperature on microstructure, mechanical properties and fracture mechanism of as-extruded Mg-10Gd-3Y-0.5Zr magnesium alloy was investigated. The results show that there have no significant changes in tensile properties of the tested alloy after 10 d in liquid nitrogen immersion or 10 cycles of high-low temperature treatment at all test temperatures. The room temperature ultimate tensile strength increases from 398 MPa to 417 MPa after 20 cycles of high-low temperature treatments. Compared with the room temperature, the tested alloys exhibit higher tensile properties at low temperatures. At -196 °C, the yield strength and ultimate tensile strength of the as-extruded-T5 Mg-10Gd-3Y-0.5Zr alloy are 349 MPa and 506 MPa, respectively, increasing by about 18% and 27%, respectively. The transgranular cleavage fracture mechanism is observed at room temperature, while at low temperatures both ductile fracture and cleavage fracture behaviors coexist.展开更多
基金supported by the National Natural Science Foundation of China(62201618).
文摘Nano-computed tomography(Nano-CT)is an emerging,high-resolution imaging technique.However,due to their low-light properties,tabletop Nano-CT has to be scanned under long exposure conditions,which the scanning process is time-consuming.For 3D reconstruction data,this paper proposed a lightweight 3D noise reduction method for desktop-level Nano-CT called AAD-ResNet(Axial Attention DeNoise ResNet).The network is framed by theU-net structure.The encoder and decoder are incorporated with the proposed 3D axial attention mechanism and residual dense block.Each layer of the residual dense block can directly access the features of the previous layer,which reduces the redundancy of parameters and improves the efficiency of network training.The 3D axial attention mechanism enhances the correlation between 3D information in the training process and captures the long-distance dependence.It can improve the noise reduction effect and avoid the loss of image structure details.Experimental results show that the network can effectively improve the image quality of a 0.1-s exposure scan to a level close to a 3-s exposure,significantly shortening the sample scanning time.
基金supported by the National Natural Science Foundation of China(Grant Nos.22275092,52102107 and 52372084)the Fundamental Research Funds for the Central Universities(Grant No.30923010920)。
文摘Energetic Semiconductor bridge(ESCB)based on reactive multilayered films(RMFs)has a promising application in the miniature and intelligence of initiator and pyrotechnics device.Understanding the ignition enhancement mechanism of RMFs on semiconductor bridge(SCB)during the ignition process is crucial for the engineering and practical application of advanced initiator and pyrotechnics devices.In this study,a one-dimensional(1D)gas-solid two-phase flow ignition model was established to study the ignition process of ESCB to charge particles based on the reactivity of Al/MoO_(3) RMFs.In order to fully consider the coupled exothermic between the RMFs and the SCB plasma during the ignition process,the heat release of chemical reaction in RMFs was used as an internal heat source in this model.It is found that the exothermal reaction in RMFs improved the ignition performance of SCB.In the process of plasma rapid condensation with heat release,the product of RMFs enhanced the heat transfer process between the gas phase and the solid charge particle,which accelerated the expansion of hot plasma,and heated the solid charge particle as well as gas phase region with low temperature.In addition,it made up for pressure loss in the gas phase.During the plasma dissipation process,the exothermal chemical reaction in RMFs acted as the main heating source to heat the charge particle,making the surface temperature of the charge particle,gas pressure,and gas temperature rise continuously.This result may yield significant advantages in providing a universal ignition model for miniaturized ignition devices.
基金funding from National Natural Science Foundation of China(52103053,52102312)Huxiang Young Talents of Hunan Province(2022RC1004)+1 种基金Macao Young Scholars Program(AM2021011)Foundation of State Key Laboratory of Utilization of Woody Oil Resource(GZKF202126)。
文摘The development of aqueous battery with dual mechanisms is now arousing more and more interest.The dual mechanisms of Zn^(2+)(de)intercalation and I^(-)/I_(2)redox bring unexpected effects.Herein,differing from previous studies using Zn I_(2)additive,this work designs an aqueous Bi I_(3)-Zn battery with selfsupplied I^(-).Ex situ tests reveal the conversion of Bi I_(3)into Bi(discharge)and Bi OI(charge)at the 1st cycle and the dissolved I^(-)in electrolyte.The active I^(-)species enhances the specific capacity and discharge medium voltage of electrode as well as improves the generation of Zn dendrite and by-product.Furthermore,the porous hard carbon is introduced to enhance the electronic/ionic conductivity and adsorb iodine species,proven by experimental and theoretical studies.Accordingly,the well-designed Bi I_(3)-Zn battery delivers a high reversible capacity of 182 m A h g^(-1)at 0.2 A g^(-1),an excellent rate capability with 88 m A h g^(-1)at 10 A g^(-1),and an impressive cyclability with 63%capacity retention over 20 K cycles at 10 A g^(-1).An excellent electrochemical performance is obtained even at a high mass loading of 6 mg cm^(-2).Moreover,a flexible quasi-solid-state Bi I_(3)-Zn battery exhibits satisfactory battery performances.This work provides a new idea for designing high-performance aqueous battery with dual mechanisms.
基金jointly supported by the projects of the China Geological Survey(DD20230092,DD20201119)。
文摘Catastrophic geological disasters frequently occur on slopes with obliquely inclined bedding structures(also referred to as obliquely inclined bedding slopes),where the apparent dip sliding is not readily visible.This phenomenon has become a focal point in landslide research.Yet,there is a lack of studies on the failure modes and mechanisms of hidden,steep obliquely inclined bedding slopes.This study investigated the Shanyang landslide in Shaanxi Province,China.Using field investigations,laboratory tests of geotechnical parameters,and the 3DEC software,this study developed a numerical model of the landslide to analyze the failure process of such slopes.The findings indicate that the Shanyang landslide primarily crept along a weak interlayer under the action of gravity.The landslide,initially following a dip angle with the support of a stable inclined rock mass,shifted direction under the influence of argillization in the weak interlayer,moving towards the apparent dip angle.The slide resistance effect of the karstic dissolution zone was increasingly significant during this process,with lateral friction being the primary resistance force.A reduction in the lateral friction due to karstic dissolution made the apparent dip sliding characteristics of the Shanyang landslide more pronounced.Notably,deformations such as bending and uplift at the slope’s foot suggest that the main slide resistance shifts from lateral friction within the karstic dissolution zone to the slope foot’s resistance force,leading to the eventual buckling failure of the landslide.This study unveils a novel failure mode of apparent dip creep-buckling in the Shanyang landslide,highlighting the critical role of lateral friction from the karstic dissolution zone in its failure mechanism.These insights offer a valuable reference for mitigating risks and preventing disasters related to obliquely inclined bedding landslides.
基金The Sixth Batch of Special Support Plans in Anhui Province(No.dlPtzjh20200050)Key Natural Science Research Project of Higher Education Institutions in Anhui Province(No.KJ2020A0426)。
文摘Objective: To investigate the effects of Yanghe Pingchuan Granules on airway remodeling in asthmatic rats, and to explore the mechanism of Interleukin-6/Janus kinase 2/ Signal transducing activator of transcription 3(IL-6/JAK2/STAT3) signal axis. Methods: We separated 42 healthy male SD rats into two groups, a control group (7) and a model group (35).The model group was sensitized with a combination of ovalbumin (OVA) and aluminum hydroxide for 2 weeks, while the control group was given an equal amount of physiological saline.After 2 weeks, the modeling group was randomly divided into Model group, Yanghe Pingchuan Granules high, medium and low dose groups and Dexamethasone group, each group consisted of 7 animals. After 4 weeks, OVA atomization and gavage were used for stimulation and treatment. Yanghe Pingchuan Granules high, middle and low groups were given 15.48, 7.74, 3.87 g∙kg-1 Yanghe Pingchuan Granules daily, dexamethasone group was given 0.0625 mg∙kg-1 dexamethasone daily, and the other groups were given the same amount of normal saline. HE, PAS and Masson staining were used to observe the lung histopathological changes in rats. The levels of interleukin-6, IL-23 and IL-17A were detected by ELISA. The expression levels of JAK-2, P-JAK2, STAT3 and P-STAT3 in lung tissues were detected by Western blot. Real-time quantitative polymerase chain reaction (qRT-PCR) was used to detect the mRNA expression levels of IL-6, JAK2 and STAT3 in rat lung tissue. Results: The lung tissue structure of the model group was severely damaged compared to the control group, accompanied by a great many of inflammatory cell infiltration, goblet cell hyperplasia, subepithelial collagen fiber deposition and airway epithelial thickening were more obvious. The expressions of IL-6, IL- 23 and IL-17A in serum were significantly increased (P<0.01), the protein expression levels of JAK-2, P-JAK2, STAT3 and P-STAT3 and the mRNA expression levels of IL-6, JAK2 and STAT3 in lung tissue were significantly increased (P<0.01);Compared with the model group, inflammatory cell infiltration, goblet cell proliferation, subepithelial collagen fiber deposition and airway epithelial thickening were significantly reduced in each administration group, and the expressions of IL-6, IL-23 and IL-17A in serum were significantly decreased (P< 0.01). The protein expression levels of JAK-2, P-JAK2, STAT3 and P-STAT3 and mRNA expression levels of IL-6, JAK2 and STAT3 in lung tissue were significantly decreased (P<0.01). Conclusion: Yanghe Pingchuan Granules can significantly alleviate airway remodeling in asthmatic rats, and its mechanism may be through inhibiting the IL-6/JAK2/STAT3 signal axis.
基金Project(51275295)supported by the National Natural Science Foundation of ChinaProject(USCAST2012-15)supported by the Funded Projects of SAST-SJTU Joint Research Centre of Advanced Aerospace Technology,ChinaProject(20120073120011)supported by the Research Fund for the Doctoral Program of Higher Education of China
文摘The microstructure, mechanical properties and fracture behavior of sand-cast Mg-10Gd-3Y-0.5Zr alloy （mass fraction,%） under T6 condition （air cooling after solid solution and then aging heat treatment） were investigated. The optimum T6 heat treatments for sand-cast Mg-10Gd-3Y-0.5Zr alloy are （525 ℃, 12 h＋225 ℃, 14 h） and （525 ℃, 12 h＋250 ℃, 12 h） according to age hardening curve and mechanical properties, respectively. The ultimate tensile strength, yield strength and elongation of the Mg-10Gd-3Y-0.5Zr alloy treated by the two optimum T6 processes are 339.9 MPa, 251.6 MPa, 1.5%and 359.6 MPa, 247.3 MPa, 2.7%, respectively. The tensile fracture mode of peak-aged Mg-10Gd-3Y-0.5Zr alloy is transgranular quasi-cleavage fracture.
基金Project supported by Tsinghua-Wuxi Science Foundation, China
文摘Al-3B master alloy is a kind of efficient grain refiner for hypoeutectic Al-Si alloys. Experiments were carried out to evaluate the effect of undissolved AlB2 particles in Al-3B master alloy on the grain refinement of Al-7Si. It is found that the number and the settlement of AlB2 particles in the melt all have effect on the grain refining efficiency. On the basis of experiments and theoretical analysis, a new grain refinement mechanism was proposed to explain the grain refinement action of Al-3B on hypoeutectic Al-Si alloys. The formation of ＇Al-AlB2＇ shell structure is the direct reason for grain refinement and the undissolved AlB2 particles is the indirect nucleating base for subsequent α（Al） phase.
文摘In order to improve the destruction efficiency of dioxins and also for developing new dioxin control technology, the destruction mechanisms of 2,3,7,8-tetrachlorodihenzo-p-dioxin （2,3,7,8-TCDD） by O3 and NO3, were investigated employing quantum chemical calculations. For involved reactions, the microcosmic reaction processes were analyzed and depicted in detail based on geometry optimizations made by the B3LYP/6-31G（d） method. At the same time, the reaction activation energies were also calculated at the MP2/6- 311G（d,p）//B3LYP/6-31G（d） level. Configuration analysis indicated that 2,3,7,8-TCDD could be destroyed by 03 and NO3 in two different ways. The destruction of 2,3,7,8-TCDD by 03 proceeded via the addition of 03 and the cleavage of C=C while the destruction of 2,3,7,8-TCDD by NO3 proceeded via the substitution of chlorine by NO3. Calculated results show that, the activation energy of the destruction reaction of 2,3,7,8-TCDD by NO3 （267.48 kJ/mol） is much larger than that of the destruction reaction of 2,3,7,8-TCDD by O3 （51.20 kJ/mol）. This indicated that the destruction of 2,3,7,8-TCDD by 03 is much more efficient than that of 2,3,7,8-TCDD by NO3. The reason why the activation energy for the destruction reaction of 2,3,7,8-TCDD by NO3 is so large, is also discussed.
基金The National High Technology Research and Development Program of China(863Program)(No.2006AA040202)
文摘One kind of movable-pair analysis method is adopted to analyze the configuration of a 3-7R （revolute-pair） parallel decoupling mechanism, and the mechanism＇s characteristics are summarized. The mechanism has three orthogonal distributional branch-chains, and all movable pairs are rotational joints. The movable platform of the mechanism has x, y, z translational decoupling directions. Furthermore, in order to verify the mechanism＇s decoupling characteristics, the mechanism＇s kinematics analysis is solved, and the mechanism＇s direct/inverse kinematics model, input/output velocities and accelerations are deduced, which confirm its decoupling movement characteristics. Finally, one kind of mechanism link decomposed-integrated approach is adopted, and the mechanism＇s dynamics model is completed with the Lagrange method, which also proves its decoupling force characteristics. All of these works provide significant theory for the further study of the mechanism＇s control strategy, design, path planning etc.
基金Project(51104185)supported by the National Natural Science Foundation of ChinaProject(2010QZZD003)supported by the Key Project of Central South University of Fundamental Research Funds for the Central Universities of China
文摘In order to explore the effect mechanism of solvent on the synthesis of the metal organic framework materials, the microscopic interaction between solvent and framework and the effects of N,N-dimethyl-formamide(DMF) or N-methyl- 2-pyrrolidone(NMP) on solvothermal synthesis of [Zn4O(BDC)3]8 were investigated through a combined DFT and experimental study. XRD and SEM showed that the absorbability of NMP in the pore of [Zn4O(BDC)3]8 was weaker than that of DMF. The thermal decomposition temperature of [Zn4O(BDC)3]8 synthesized in DMF was higher than that in NMP according to TG and FT-IR. In addition, the nitrogen sorption isotherms indicated that NMP improved gas sorption property of [Zn4O(BDC)3]8. The COSMO optimized calculations indicated that the total energy of Zn4O(BDC)3 in NMP was higher than that in DMF, and compared with non-solvent system, the charge of zinc atoms decreased and the charge value was the smallest in NMP. Furthermore, the interaction of DMF, NMP or DEF in [Zn4O(BDC)3]8 crystal model was calculated by DFT method. The results suggested that NMP should be easier to be removed from pore of materials than DMF from the point of view of energy state. It can be concluded that NMP was a favorable solvent to synthesize [Zn4O(BDC)3]8 and the microscopic mechanism was that the binding force between Zn4O(BDC)3 and NMP molecule was weaker than DMF.
基金Project(21301193)supported by the National Nature Science Foundation of ChinaProject(2013M530356)supported by the China Postdoctoral Science Foundation Funded+1 种基金Project(CUSZC201303)supported by the Scientific Research Foundation of Central South Universitythe Open-End Found for Valuable and Precision Instruments of Central South University
文摘Electrochemical behavior of layered LiNi0.5Mn0.5O2 in LiNO3 aqueous solution and its cyclic fading mechanism in electrolytes with different pH values were investigated. CV results show that LiNi0.5Mn0.5O2 has good electrochemical reversible behaviors in 5 mol/L LiNO3 solution. Meanwhile, the electrode in 5 mol/L LiNO3 with pH value of 12 demonstrates the best electrochemical stability. Based on the electrochemical impedance spectroscopy （EIS）, X-ray diffraction （XRD） and scanning electron microscopy （SEM） results, it is proposed that suppressed charge-transfer resistance is the major reason, which is probably ascribed to the more stable electrode surface and less structure change.
基金Project (51275295) supported by the National Natural Science Foundation of ChinaProject (USCAST2012-15) supported by the Funded Projects of SAST-SJTU Aerospace Advanced Technology Joint Research Centre, ChinaProject (20120073120011) supported by the Research Fund for the Doctoral Program of Higher Education of China
文摘Influence of multi-cycle cryogenic treatment and tensile temperature on microstructure, mechanical properties and fracture mechanism of as-extruded Mg-10Gd-3Y-0.5Zr magnesium alloy was investigated. The results show that there have no significant changes in tensile properties of the tested alloy after 10 d in liquid nitrogen immersion or 10 cycles of high-low temperature treatment at all test temperatures. The room temperature ultimate tensile strength increases from 398 MPa to 417 MPa after 20 cycles of high-low temperature treatments. Compared with the room temperature, the tested alloys exhibit higher tensile properties at low temperatures. At -196 °C, the yield strength and ultimate tensile strength of the as-extruded-T5 Mg-10Gd-3Y-0.5Zr alloy are 349 MPa and 506 MPa, respectively, increasing by about 18% and 27%, respectively. The transgranular cleavage fracture mechanism is observed at room temperature, while at low temperatures both ductile fracture and cleavage fracture behaviors coexist.
