An explicit polycrystal plasticity model was proposed to investigate the deformation mechanism of cold ring rolling in view of texture evolution. The model was created by deducing a set of linear incremental controlli...An explicit polycrystal plasticity model was proposed to investigate the deformation mechanism of cold ring rolling in view of texture evolution. The model was created by deducing a set of linear incremental controlling equations within the framework of crystal plasticity theory. It was directly solved by a linear algorithm within a two-level procedure so that its efficiency and stability were guaranteed. A subroutine VUMAT for ABAQUS/Explicit was developed to combine this model with the 3D FE model of cold ring rolling. Results indicate that the model is reliable in predictions of stress-strain response and texture evolution in the dynamic complicated forming process; the shear strain in RD of the ring is the critical deformation mode according to the sharp Goss component ({110}?100?) of deformed ring; texture and crystallographic structure of the ring blank do not affect texture type of the deformed ring;texture evolves rapidly at the later stage of rolling, which results in a dramatically increasing deformation of the ring.展开更多
The 2024Al/Gr/SiC hybrid composite plates with 5%-10% SiC particles (volume fraction) and 3%-6% flaky graphite (Gr) (volume fraction) were fabricated by vacuum hot pressing and hot extrusion processing. The effe...The 2024Al/Gr/SiC hybrid composite plates with 5%-10% SiC particles (volume fraction) and 3%-6% flaky graphite (Gr) (volume fraction) were fabricated by vacuum hot pressing and hot extrusion processing. The effects of SiC and Gr on the microstructures and mechanical properties of the composites aged at 160, 175 and 190℃ were studied by optical microscopy, scanning electron microscopy (SEM), and hardness and tensile tests. The results indicate that the SiC particles have a more obvious effect on accelerating the aging response as compared with the Gr. Both the tensile strength and elongation are reduced by the Gr and SiC particles added into the matrix, while the Gr has a more negative influence on the elongation than the SiC particles. The tensile strength (ab), yield stress (as) and elongation (δ) of the 2024Al/3Gr/10SiC composite aged at 165℃ for 8 h are 387 MPa, 280.3 MPa and 5.7%, respectively. The hybrid composites are characterized by ductile fracture, which is associated with the ductile fracture of the matrix and the tearing of the interface between the matrix and the particles.展开更多
Grain scale plasticity of NiTi shape memory alloy(SMA)during uniaxial compression deformation at 400℃was investigated through two-dimensional crystal plasticity finite element simulation and corresponding analysis ba...Grain scale plasticity of NiTi shape memory alloy(SMA)during uniaxial compression deformation at 400℃was investigated through two-dimensional crystal plasticity finite element simulation and corresponding analysis based on the obtained orientation data.Stress and strain distributions of the deformed NiTi SMA samples confirm that there exhibits a heterogeneous plastic deformation at grain scale.Statistically stored dislocation(SSD)density and geometrically necessary dislocation(GND)density were further used in order to illuminate the microstructure evolution during uniaxial compression.SSD is responsible for sustaining plastic deformation and it increases along with the increase of plastic strain.GND plays an important role in accommodating compatible deformation between individual grains and thus it is correlated with the misorientation between neighboring grains,namely,a high GND density corresponds to large misorientation between grains and a low GND density corresponds to small misorientation between grains.展开更多
Objective To evaluate and compare the ability to detect tumor by bis (N-ethoxy-N-ethyl dithiocarbamato) nitrido99mTc(V) [99mTcN(NOEt)2] and99mTc hexakis-2- methoxyisobutyl isonitrile [99mTc-MIBI]. Methods 99mTcN(NOE...Objective To evaluate and compare the ability to detect tumor by bis (N-ethoxy-N-ethyl dithiocarbamato) nitrido99mTc(V) [99mTcN(NOEt)2] and99mTc hexakis-2- methoxyisobutyl isonitrile [99mTc-MIBI]. Methods 99mTcN(NOEt)2 was prepared and quality control was performed using ascending thin-layer chromatography. Four mice bearing Ehrich ascites tumor cells underwent whole body planar imaging at 30 min, 2 h and 4 h after injection of99mTc-MIBI or99mTcN(NOEt)2. ROIs were drawn around the tumor, head, chest, and contralateral limbs in whole body planar images, and ratios of radioactivity in tumor in head (T/H), chest (T/C), and contralateral limbs (T/L) were calculated. The mice of99mTcN (NOEt)2 group were killed, then blood was collected, and the tumor and organs were excised, weighed and the radioactivity was measured. Results 99mTcN(NOEt)2 was stable after 4h at the room temperature.99mTcN(NOEt)2 was delivered to the tumor selectively and efficiently.99mTcN(NOEt)2 was found to provide excellent tumor-to-nontumor contrast for all the tissue except the abdomen. The T/L ratios increased to their maximums (4.87) at 2 h after injection. There was significant difference between the99mTcN(NOEt)2 imaging group and99mTc-MIBI imaging group. In vitro the radioactivity ratios per unit weight of tumor to blood, muscle, skeleton, lung, heart, and spleen were much higher than those of tumor to liver, instestine. Conclusion In mice bearing Ehrich ascites tumor,99mTcN(NOEt)2 exhibits a set of features essential for a good tracer for tumor imaging, including a rapid washout from blood, high uptake rate in tumor tissue, prolonged retention and high tumor-to-nontumor uptake ratio. The imaging quality of99mTcN(NOEt)2 was superior to that of99mTc-MIBI. These features indicate that99mTcN(NOEt)2 may be a better tracer to detect tumor than99mTc-MIBI. Key words tumor - radionuclide imaging - NOEt - MIBI展开更多
Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited monogenic kidney disease. Characterized by the development and growth of cysts that cause progressive kidney enlargement, it ultimate...Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited monogenic kidney disease. Characterized by the development and growth of cysts that cause progressive kidney enlargement, it ultimately leads to end-stage renal disease. Approximately 85% of ADPKD cases are caused by mutations in the PKD1 gene, while mutations in the PKD2 gene account for the remaining 15% of cases. The PKD1 gene encodes for polycystin-1 (PC1), a large multi-functional memb-rane receptor protein able to regulate ion channel complexes, whereas polycystin-2 (PC2), encoded by the PKD2 gene, is an integral membrane protein that functions as a calcium-permeable cation channel, located mainly in the endoplasmic reticulum (ER). In the primary cilia of the epithelial cells, PC1 interacts with PC2 to form a polycystin complex that acts as a mechanosensor, regulating signaling pathways involved in the differentiation of kidney tubular epithelial cells. Despite progress in understanding the function of these proteins, the molecular mechanisms associated with the pathogenesis of ADPKD remain unclear. In this review we discuss how an imbalance between functional PC1 and PC2 proteins may disrupt calcium channel activities in the cilium, plasma membrane and ER, thereby altering intracellular calcium signaling and leading to the aberrant cell proliferation and apoptosis associated with the development and growth of renal cysts. Research in this feld could lead to the discovery of new molecules able to rebalance intracellular calcium, thereby normalizing cell proliferation and reducing kidney cyst progression.展开更多
Land use structure optimization(LUSO) is an important issue for land use planning. In order for land use planning to have reasonable flexibility, uncertain optimization should be applied for LUSO. In this paper, the r...Land use structure optimization(LUSO) is an important issue for land use planning. In order for land use planning to have reasonable flexibility, uncertain optimization should be applied for LUSO. In this paper, the researcher first expounded the uncertainties of LUSO. Based on this, an interval programming model was developed, of which interval variables were to hold land use uncertainties. To solve the model, a heuristics based on Genetic Algorithm was designed according to Pareto Optimum principle with a confidence interval under given significance level to represent LUSO result. Proposed method was applied to a real case of Yangzhou, an eastern city in China. The following conclusions were reached. 1) Different forms of uncertainties ranged from certainty to indeterminacy lay in the five steps of LUSO, indicating necessary need of comprehensive approach to quantify them. 2) With regards to trade-offs of conflicted objectives and preferences to uncertainties, our proposed model displayed good ability of making planning decision process transparent, therefore providing an effective tool for flexible land use planning compiling. 3) Under uncertain conditions, land use planning effectiveness can be primarily enhanced by flexible management with reserved space to percept and hold uncertainties in advance.展开更多
To examine the influence of the structural parameters and working parameters of a double-drum regeneration mixing station on its mixing uniformity,the influence of the discrete element method and response surface meth...To examine the influence of the structural parameters and working parameters of a double-drum regeneration mixing station on its mixing uniformity,the influence of the discrete element method and response surface method on the uniformity of the aggregate mixing when the interaction between two different factors was analyzed.A mathematical model of the influence of various factors and interactions on the coefficient of variation of the aggregates was established.The matching of each parameter was optimized with the goal of minimizing the coefficient of variation.The results show that when the aggregate particle size is different,the significance of each parameter affecting its mixing uniformity is also different.Moreover,increasing the speed and reducing the axial installation angle of the blade can reduce the coefficient of variation of the three aggregates.To obtain a good mixing uniformity,the mixing-arm phase angle when the drum inclination angle is large should be smaller than the phase angle when the drum inclination angle is small,and the mixing of large particles should not be arranged with a large mixing-arm phase angle.With a blade radial installation angle of 38°,a blade axial installation angle of 35°,a drum inclination angle of 6°,a drum rotation speed of 10 r/min,and a mixing-arm phase angle of 32°,the aggregate as a whole can exhibit the best mixing uniformity.展开更多
Pure ZnS and Ni^2+-doped ZnS nanorods (Zn1-xNixS, x=0, 0.01, 0.03, 0.05 and 0.07, mole fraction,%) were synthesized by hydrothermal method. The effects of Ni2+ doping on the phase-structure, morphology, elemental comp...Pure ZnS and Ni^2+-doped ZnS nanorods (Zn1-xNixS, x=0, 0.01, 0.03, 0.05 and 0.07, mole fraction,%) were synthesized by hydrothermal method. The effects of Ni2+ doping on the phase-structure, morphology, elemental composition and optical properties of the samples were investigated by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), X-ray energy dispersive spectrometry (EDS) and ultraviolet–visible spectroscopy (UV-Vis), respectively. The photocatalytic activity of Zn1-xNixS nanorods was evaluated by the photodegradation of organic dyes Rhodamine B (RhB) in aqueous solution under UV light irradiation. The results show that all samples exhibit wurtzite structure with good crystallization. The morphologies are one-dimensional nanorods with good dispersion, and the distortion of the lattice constant occurs. The band gap of Zn1-xNixS samples is smaller than that of pure ZnS, thus red shift occurs. Ni^2+-doped ZnS nanocrystals can enhance photocatalytic activities for the photodegradation of RhB. Especially, Zn0.97Ni0.03S sample exhibits better photocatalytic performance and photocatalytic stability for the decomposition of RhB.展开更多
Rigid-viscoplastic3D finite element simulations(3D FEM)of the equal channel angular pressing(ECAP),thecombination of ECAP+extrusion with different extrusion ratios,and direct extrusion of pure aluminum were performed ...Rigid-viscoplastic3D finite element simulations(3D FEM)of the equal channel angular pressing(ECAP),thecombination of ECAP+extrusion with different extrusion ratios,and direct extrusion of pure aluminum were performed andanalyzed.The3D FEM simulations were carried out to investigate the load-displacement behavior,the plastic deformationcharacteristics and the effective plastic strain homogeneity of Al-1080deformed by different forming processes.The simulationresults were validated by microstructure observations,microhardness distribution maps and the correlation between the effectiveplastic strain and the microhardness values.The3D FEM simulations were performed successfully with a good agreement with theexperimental results.The load-displacement curves and the peak load values of the3D FEM simulations and the experimentalresults were close from each other.The microhardness distribution maps were in a good conformity with the effective plastic straincontours and verifying the3D FEM simulations results.The ECAP workpiece has a higher degree of deformation homogeneity thanthe other deformation processes.The microhardness values were calculated based on the average effective plastic strain.Thepredicted microhardness values fitted the experimental results well.The microstructure observations in the longitudinal andtransverse directions support the3D FEM effective plastic strain and microhardness distributions result in different formingprocesses.展开更多
The status of English grammar teaching in English teaching has weakened and even once disappeared in part English class; until the late 1980s, foreign English teachers had a consistent view of the importance of gramma...The status of English grammar teaching in English teaching has weakened and even once disappeared in part English class; until the late 1980s, foreign English teachers had a consistent view of the importance of grammar teaching. In recent years, more and more domestic scholars begin to think about the situation of China and explore the grammar teaching method. This article will review the explicit grammar instruction and implicit grammar teaching research, collect and analyze the integration of explicit grammar instruction and implicit grammar teaching strategy and its advantages in the grammar teaching.展开更多
In order to investigate the seismic performance of geosynthetic reinforced and pile supported(GRPS) embankment under seismic loads, an input method for three-dimensional oblique incidence of P wave was proposed. This ...In order to investigate the seismic performance of geosynthetic reinforced and pile supported(GRPS) embankment under seismic loads, an input method for three-dimensional oblique incidence of P wave was proposed. This method is based on the explicit finite element method while considering the viscous-spring artificial boundary(VSAB) condition. Using the proposed method, a numerical study was conducted, and the influence of oblique incidence on the seismic response of GRPS embankment under the oblique incident P waves was analyzed. The results indicate that in comparison with vertical incidence, the oblique incidence can significantly increase the displacement, velocity and acceleration of key locations in the GRPS embankment. The existence of geosynthetics can alleviate the impact of seismic load on the response of the embankment to a certain degree. Moreover, the number of reinforcement layers and modulus of geogrid also greatly influence the seismic performance of GRPS embankment.展开更多
Meckel's diverticulum is a common asymptomatic congenital gastrointestinal anomaly,but rarely it can present with hemorrhage.Over the last few years inverted Meckel's diverticulum has been reported in the lite...Meckel's diverticulum is a common asymptomatic congenital gastrointestinal anomaly,but rarely it can present with hemorrhage.Over the last few years inverted Meckel's diverticulum has been reported in the literature with increasing frequency as an occult source of lower gastrointestinal hemorrhage.Here,we report a case of a 54-year-old male,who was referred for surgical evaluation with persistent anemia and occult blood per rectum after a work up which failed to localize the source over 12 mo,including upper and capsule endoscopy,colonoscopy,enteroclysis,Meckel scan,and tagged nuclear red blood cell scan.An abdominal computed tomography scan showed a possible mid-ileal intussusception and intraluminal mass.During the abdominal exploration,inverted Meckel's diverticulum was diagnosed and resected.We review the literature,discuss the forms in which the disease presents,the diagnostic modalities utilized,pathological findings,and treatment.Although less than 40 cases have been reported in the English literature from 1978 to 2005,19 cases have been reported in the last 6 years alone(2006-2012) due to improved diagnostic modalities.Successful diagnosis and treatment of this disease requires a high index of clinical suspicion,which is becoming increasingly relevant to general gastroenterologists.展开更多
基金Project (51175428) supported by the National Natural Science Foundation of ChinaProject (B08040) supported by Program of Introducing Talents of Discipline to Universities ("111"Project),China
文摘An explicit polycrystal plasticity model was proposed to investigate the deformation mechanism of cold ring rolling in view of texture evolution. The model was created by deducing a set of linear incremental controlling equations within the framework of crystal plasticity theory. It was directly solved by a linear algorithm within a two-level procedure so that its efficiency and stability were guaranteed. A subroutine VUMAT for ABAQUS/Explicit was developed to combine this model with the 3D FE model of cold ring rolling. Results indicate that the model is reliable in predictions of stress-strain response and texture evolution in the dynamic complicated forming process; the shear strain in RD of the ring is the critical deformation mode according to the sharp Goss component ({110}?100?) of deformed ring; texture and crystallographic structure of the ring blank do not affect texture type of the deformed ring;texture evolves rapidly at the later stage of rolling, which results in a dramatically increasing deformation of the ring.
文摘The 2024Al/Gr/SiC hybrid composite plates with 5%-10% SiC particles (volume fraction) and 3%-6% flaky graphite (Gr) (volume fraction) were fabricated by vacuum hot pressing and hot extrusion processing. The effects of SiC and Gr on the microstructures and mechanical properties of the composites aged at 160, 175 and 190℃ were studied by optical microscopy, scanning electron microscopy (SEM), and hardness and tensile tests. The results indicate that the SiC particles have a more obvious effect on accelerating the aging response as compared with the Gr. Both the tensile strength and elongation are reduced by the Gr and SiC particles added into the matrix, while the Gr has a more negative influence on the elongation than the SiC particles. The tensile strength (ab), yield stress (as) and elongation (δ) of the 2024Al/3Gr/10SiC composite aged at 165℃ for 8 h are 387 MPa, 280.3 MPa and 5.7%, respectively. The hybrid composites are characterized by ductile fracture, which is associated with the ductile fracture of the matrix and the tearing of the interface between the matrix and the particles.
基金Projects(51475101,51305091,51305092)supported by the National Natural Science Foundation of China
文摘Grain scale plasticity of NiTi shape memory alloy(SMA)during uniaxial compression deformation at 400℃was investigated through two-dimensional crystal plasticity finite element simulation and corresponding analysis based on the obtained orientation data.Stress and strain distributions of the deformed NiTi SMA samples confirm that there exhibits a heterogeneous plastic deformation at grain scale.Statistically stored dislocation(SSD)density and geometrically necessary dislocation(GND)density were further used in order to illuminate the microstructure evolution during uniaxial compression.SSD is responsible for sustaining plastic deformation and it increases along with the increase of plastic strain.GND plays an important role in accommodating compatible deformation between individual grains and thus it is correlated with the misorientation between neighboring grains,namely,a high GND density corresponds to large misorientation between grains and a low GND density corresponds to small misorientation between grains.
文摘Objective To evaluate and compare the ability to detect tumor by bis (N-ethoxy-N-ethyl dithiocarbamato) nitrido99mTc(V) [99mTcN(NOEt)2] and99mTc hexakis-2- methoxyisobutyl isonitrile [99mTc-MIBI]. Methods 99mTcN(NOEt)2 was prepared and quality control was performed using ascending thin-layer chromatography. Four mice bearing Ehrich ascites tumor cells underwent whole body planar imaging at 30 min, 2 h and 4 h after injection of99mTc-MIBI or99mTcN(NOEt)2. ROIs were drawn around the tumor, head, chest, and contralateral limbs in whole body planar images, and ratios of radioactivity in tumor in head (T/H), chest (T/C), and contralateral limbs (T/L) were calculated. The mice of99mTcN (NOEt)2 group were killed, then blood was collected, and the tumor and organs were excised, weighed and the radioactivity was measured. Results 99mTcN(NOEt)2 was stable after 4h at the room temperature.99mTcN(NOEt)2 was delivered to the tumor selectively and efficiently.99mTcN(NOEt)2 was found to provide excellent tumor-to-nontumor contrast for all the tissue except the abdomen. The T/L ratios increased to their maximums (4.87) at 2 h after injection. There was significant difference between the99mTcN(NOEt)2 imaging group and99mTc-MIBI imaging group. In vitro the radioactivity ratios per unit weight of tumor to blood, muscle, skeleton, lung, heart, and spleen were much higher than those of tumor to liver, instestine. Conclusion In mice bearing Ehrich ascites tumor,99mTcN(NOEt)2 exhibits a set of features essential for a good tracer for tumor imaging, including a rapid washout from blood, high uptake rate in tumor tissue, prolonged retention and high tumor-to-nontumor uptake ratio. The imaging quality of99mTcN(NOEt)2 was superior to that of99mTc-MIBI. These features indicate that99mTcN(NOEt)2 may be a better tracer to detect tumor than99mTc-MIBI. Key words tumor - radionuclide imaging - NOEt - MIBI
基金Supported by University of Ferrara local funds:FAR 2012,2013,2014 and Regione Emilia Romagna grant(Ricerca Regione-Università)2007-2009
文摘Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited monogenic kidney disease. Characterized by the development and growth of cysts that cause progressive kidney enlargement, it ultimately leads to end-stage renal disease. Approximately 85% of ADPKD cases are caused by mutations in the PKD1 gene, while mutations in the PKD2 gene account for the remaining 15% of cases. The PKD1 gene encodes for polycystin-1 (PC1), a large multi-functional memb-rane receptor protein able to regulate ion channel complexes, whereas polycystin-2 (PC2), encoded by the PKD2 gene, is an integral membrane protein that functions as a calcium-permeable cation channel, located mainly in the endoplasmic reticulum (ER). In the primary cilia of the epithelial cells, PC1 interacts with PC2 to form a polycystin complex that acts as a mechanosensor, regulating signaling pathways involved in the differentiation of kidney tubular epithelial cells. Despite progress in understanding the function of these proteins, the molecular mechanisms associated with the pathogenesis of ADPKD remain unclear. In this review we discuss how an imbalance between functional PC1 and PC2 proteins may disrupt calcium channel activities in the cilium, plasma membrane and ER, thereby altering intracellular calcium signaling and leading to the aberrant cell proliferation and apoptosis associated with the development and growth of renal cysts. Research in this feld could lead to the discovery of new molecules able to rebalance intracellular calcium, thereby normalizing cell proliferation and reducing kidney cyst progression.
基金Under the auspices of National Natural Science Foundation of China(No.41401627,41471144)Foundation Research Project of Jiangsu Province(No.BK20140236)
文摘Land use structure optimization(LUSO) is an important issue for land use planning. In order for land use planning to have reasonable flexibility, uncertain optimization should be applied for LUSO. In this paper, the researcher first expounded the uncertainties of LUSO. Based on this, an interval programming model was developed, of which interval variables were to hold land use uncertainties. To solve the model, a heuristics based on Genetic Algorithm was designed according to Pareto Optimum principle with a confidence interval under given significance level to represent LUSO result. Proposed method was applied to a real case of Yangzhou, an eastern city in China. The following conclusions were reached. 1) Different forms of uncertainties ranged from certainty to indeterminacy lay in the five steps of LUSO, indicating necessary need of comprehensive approach to quantify them. 2) With regards to trade-offs of conflicted objectives and preferences to uncertainties, our proposed model displayed good ability of making planning decision process transparent, therefore providing an effective tool for flexible land use planning compiling. 3) Under uncertain conditions, land use planning effectiveness can be primarily enhanced by flexible management with reserved space to percept and hold uncertainties in advance.
基金The Natural Science Basic Research Plan in Shaanxi Province(No.2017JM5077)the Fundamental Research Funds for the Central Universities under Grant(No.300102259109).
文摘To examine the influence of the structural parameters and working parameters of a double-drum regeneration mixing station on its mixing uniformity,the influence of the discrete element method and response surface method on the uniformity of the aggregate mixing when the interaction between two different factors was analyzed.A mathematical model of the influence of various factors and interactions on the coefficient of variation of the aggregates was established.The matching of each parameter was optimized with the goal of minimizing the coefficient of variation.The results show that when the aggregate particle size is different,the significance of each parameter affecting its mixing uniformity is also different.Moreover,increasing the speed and reducing the axial installation angle of the blade can reduce the coefficient of variation of the three aggregates.To obtain a good mixing uniformity,the mixing-arm phase angle when the drum inclination angle is large should be smaller than the phase angle when the drum inclination angle is small,and the mixing of large particles should not be arranged with a large mixing-arm phase angle.With a blade radial installation angle of 38°,a blade axial installation angle of 35°,a drum inclination angle of 6°,a drum rotation speed of 10 r/min,and a mixing-arm phase angle of 32°,the aggregate as a whole can exhibit the best mixing uniformity.
基金Project(51261015)supported by the National Natural Science Foundation of ChinaProject(1308RJZA238)supported by the Natural Science Foundation of Gansu Province,China
文摘Pure ZnS and Ni^2+-doped ZnS nanorods (Zn1-xNixS, x=0, 0.01, 0.03, 0.05 and 0.07, mole fraction,%) were synthesized by hydrothermal method. The effects of Ni2+ doping on the phase-structure, morphology, elemental composition and optical properties of the samples were investigated by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), X-ray energy dispersive spectrometry (EDS) and ultraviolet–visible spectroscopy (UV-Vis), respectively. The photocatalytic activity of Zn1-xNixS nanorods was evaluated by the photodegradation of organic dyes Rhodamine B (RhB) in aqueous solution under UV light irradiation. The results show that all samples exhibit wurtzite structure with good crystallization. The morphologies are one-dimensional nanorods with good dispersion, and the distortion of the lattice constant occurs. The band gap of Zn1-xNixS samples is smaller than that of pure ZnS, thus red shift occurs. Ni^2+-doped ZnS nanocrystals can enhance photocatalytic activities for the photodegradation of RhB. Especially, Zn0.97Ni0.03S sample exhibits better photocatalytic performance and photocatalytic stability for the decomposition of RhB.
文摘Rigid-viscoplastic3D finite element simulations(3D FEM)of the equal channel angular pressing(ECAP),thecombination of ECAP+extrusion with different extrusion ratios,and direct extrusion of pure aluminum were performed andanalyzed.The3D FEM simulations were carried out to investigate the load-displacement behavior,the plastic deformationcharacteristics and the effective plastic strain homogeneity of Al-1080deformed by different forming processes.The simulationresults were validated by microstructure observations,microhardness distribution maps and the correlation between the effectiveplastic strain and the microhardness values.The3D FEM simulations were performed successfully with a good agreement with theexperimental results.The load-displacement curves and the peak load values of the3D FEM simulations and the experimentalresults were close from each other.The microhardness distribution maps were in a good conformity with the effective plastic straincontours and verifying the3D FEM simulations results.The ECAP workpiece has a higher degree of deformation homogeneity thanthe other deformation processes.The microhardness values were calculated based on the average effective plastic strain.Thepredicted microhardness values fitted the experimental results well.The microstructure observations in the longitudinal andtransverse directions support the3D FEM effective plastic strain and microhardness distributions result in different formingprocesses.
文摘The status of English grammar teaching in English teaching has weakened and even once disappeared in part English class; until the late 1980s, foreign English teachers had a consistent view of the importance of grammar teaching. In recent years, more and more domestic scholars begin to think about the situation of China and explore the grammar teaching method. This article will review the explicit grammar instruction and implicit grammar teaching research, collect and analyze the integration of explicit grammar instruction and implicit grammar teaching strategy and its advantages in the grammar teaching.
基金Projects(41202220,41472278,51478438)supported by the National Natural Science Foundation of ChinaProjects(20120022120003,20134101120009)supported by the Research Fund for the Doctoral Program of Higher Education,China+1 种基金Project(2652012065)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(14A560014)supported by the Key Project of Education Department in Henan Province,China
文摘In order to investigate the seismic performance of geosynthetic reinforced and pile supported(GRPS) embankment under seismic loads, an input method for three-dimensional oblique incidence of P wave was proposed. This method is based on the explicit finite element method while considering the viscous-spring artificial boundary(VSAB) condition. Using the proposed method, a numerical study was conducted, and the influence of oblique incidence on the seismic response of GRPS embankment under the oblique incident P waves was analyzed. The results indicate that in comparison with vertical incidence, the oblique incidence can significantly increase the displacement, velocity and acceleration of key locations in the GRPS embankment. The existence of geosynthetics can alleviate the impact of seismic load on the response of the embankment to a certain degree. Moreover, the number of reinforcement layers and modulus of geogrid also greatly influence the seismic performance of GRPS embankment.
基金Supported by United States National Institute of Health grants,K12HD055881 and R01CA160688,to Takabe KJapan Society for the Promotion of Science Postdoctoral Fellowship for Re-search Abroad,to Nagahashi M
文摘Meckel's diverticulum is a common asymptomatic congenital gastrointestinal anomaly,but rarely it can present with hemorrhage.Over the last few years inverted Meckel's diverticulum has been reported in the literature with increasing frequency as an occult source of lower gastrointestinal hemorrhage.Here,we report a case of a 54-year-old male,who was referred for surgical evaluation with persistent anemia and occult blood per rectum after a work up which failed to localize the source over 12 mo,including upper and capsule endoscopy,colonoscopy,enteroclysis,Meckel scan,and tagged nuclear red blood cell scan.An abdominal computed tomography scan showed a possible mid-ileal intussusception and intraluminal mass.During the abdominal exploration,inverted Meckel's diverticulum was diagnosed and resected.We review the literature,discuss the forms in which the disease presents,the diagnostic modalities utilized,pathological findings,and treatment.Although less than 40 cases have been reported in the English literature from 1978 to 2005,19 cases have been reported in the last 6 years alone(2006-2012) due to improved diagnostic modalities.Successful diagnosis and treatment of this disease requires a high index of clinical suspicion,which is becoming increasingly relevant to general gastroenterologists.