The microstructure and the characteristics of the inclusions embedded in ferrite matrix in simulated coarse-grain heat affected zone (CGHAZ) of a Ti-Zr-treated high strength low alloy (HSLA) steel have been investigat...The microstructure and the characteristics of the inclusions embedded in ferrite matrix in simulated coarse-grain heat affected zone (CGHAZ) of a Ti-Zr-treated high strength low alloy (HSLA) steel have been investigated. The microstructure of the simulated CGHAZ dominantly consisted of intragranular acicular ferrite (IAF) combining with a small amount of polygonal ferrite (PF), widmanst tten ferrite (WF), bainite ferrite (BF), pearlite and martensite-austenite (M-A) islands. The PF, WF and BF were generally observed at the prior austenite grain boundaries and the interlocking acicular ferrite was usually found intragranularly. It was found that the inclusions were composed of Ti2O3, ZrO2, Al2O3 locating at the center of the particles and MnS lying on the surface layer of the inclusions. The intragranular complex inclusions promoted the acicular ferrite formation and the refinement of microstructure whilst those at prior austenite grain boundaries caused PF formation on the inclusions. The simulated CGHAZ consisting of such complicated microstructure exhibited desired mechanical properties.展开更多
Rehearing furnace is an important device with complex dynamic characteristicsin steel plants. The temperature tracing control of reheating furnace has great importance both tothe quality of slabs and energy saving. A ...Rehearing furnace is an important device with complex dynamic characteristicsin steel plants. The temperature tracing control of reheating furnace has great importance both tothe quality of slabs and energy saving. A model-based control strategy, multivariable constrainedcontrol (MCC) for the reheating furnace control is used. With this control method, the furnace istreated as a six-input-six-output general model with loops coupled in nature. Compared with thetraditional control, the proposed control strategy gets better temperature tracing accuracy andexhibits some energy saving feature. The simulation results show that the performance of the furnaceis greatly improved.展开更多
The oxidation behavior of high speed steel (HSS) was researched by high temperature thermo balance at 500 to 800 °C in water vapor. The morphology was observed by scanning electron microscope, the microstructure ...The oxidation behavior of high speed steel (HSS) was researched by high temperature thermo balance at 500 to 800 °C in water vapor. The morphology was observed by scanning electron microscope, the microstructure of oxide scale was analyzed by energy dispersive spectrometer and X-ray diffraction spectrum. The results indicate that the mass gain of HSS increases with oxidation temperature rising, the effect of oxidation temperature on the morphology is obvious, water vapor temperature only affects mass gain and affects hardly morphology of oxide scale at the same oxidation temperature. The relevant oxidation mechanisms are also discussed.展开更多
A reputation mechanism is introduced in P2P- based Semantic Web to solve the problem of lacking trust. It enables Semantic Web to utilize reputation information based on semantic similarity of peers in the network. Th...A reputation mechanism is introduced in P2P- based Semantic Web to solve the problem of lacking trust. It enables Semantic Web to utilize reputation information based on semantic similarity of peers in the network. This approach is evaluated in a simulation of a content sharing system and the experiments show that the system with reputation mechanism outperforms the system without it.展开更多
The oxidation characteristics of high speed steel (HSS) were studied at 500 to 800°C. The non-isothermal oxidation and isothermal oxidation (500, 575, 650, 725, 800°C) of HSS were investigated by thermo-gra...The oxidation characteristics of high speed steel (HSS) were studied at 500 to 800°C. The non-isothermal oxidation and isothermal oxidation (500, 575, 650, 725, 800°C) of HSS were investigated by thermo-gravimetric analysis (TGA). The microstruc- ture, morphology and oxide scale thickness of the isothermal oxidation samples were analyzed by optical microscope (OM), electron probe micro analyzer (EPMA), X-ray diffraction spectrum (XRD) and scanning electron microscope (SEM). The results indicate that the oxidation rate of HSS is very slow at 500 to 650°C, increasing gradually at 650 to 750°C, and drastically at 750 to 800°C, be- cause the phase transformation happens at about 750°C.展开更多
In this paper,we present a strategy to implement multi-pose face detection in compressed domain.The strategy extracts firstly feature vectors from DCT domain,and then uses a boosting algorithm to build classificrs to ...In this paper,we present a strategy to implement multi-pose face detection in compressed domain.The strategy extracts firstly feature vectors from DCT domain,and then uses a boosting algorithm to build classificrs to distinguish faces and non-faces.Moreover,to get more accurate results of the face detection,we present a kernel function and a linear combination to build incrementally the strong classifiers based on the weak classifiers.Through comparing and analyzing results of some experiments on the synthetic data and the natural data,we can get more satisfied results by the strong classifiers than by the weak classifies.展开更多
A mathematical model describing the behavior of metal inert gas (MIG) welding isformulated in the paper. By means of numerical simulation, the influence of surface-active elements on fluid flow of MIG weldpool is stud...A mathematical model describing the behavior of metal inert gas (MIG) welding isformulated in the paper. By means of numerical simulation, the influence of surface-active elements on fluid flow of MIG weldpool is studied. The calculation resultsshow that by adding surface-active elements, the fluid flow behavior is drasticallychanged and the flow fluid flows from lower to upper in vertical direction at the rearof weldpool (w>0). The physical phenomenon is explained from the viewpoint of fluidflow behavior of weldpool that the properties of weld metal is greatly improved andthe content of diffused hydrogen is reduced, thus providing a basis for developing newwelding materials.展开更多
The paper describes the recent developing situation and the latest research achievements of refractory for hot metal pretreatment. The relationship among desiliconization, dephosphorization and desulphurization techni...The paper describes the recent developing situation and the latest research achievements of refractory for hot metal pretreatment. The relationship among desiliconization, dephosphorization and desulphurization techniques and the main corrosion reactions by various treating agents is analyzed. Some improving measures for several problems in practice are put forward while we anticipate the future developing direction of refractory for hot metal pretreatment.展开更多
Cells in vivo reside within a complex microenvironment that is rich in biological,chemical and mechanical cues,playing critical roles in regulating cellular activities(e.g.,proliferation,migration,differentiation)both...Cells in vivo reside within a complex microenvironment that is rich in biological,chemical and mechanical cues,playing critical roles in regulating cellular activities(e.g.,proliferation,migration,differentiation)both spatially and temporally.Although it is well accepted that biochemical cues can significantly influence cell functions,accumulating evidence has also shown that mechanical feedback from the cell microenvironment(e.g.,stiffness of ECM,morphology,and tension force)also plays an important role in controlling cell fate.Disequilibrium of the mechanical microenvironment is associated with a series of diseases,such as cancer migration and tissue fibrosis.Thus,there is a pressing need to understand how cells transduce these mechanobiological cues.The cell cytoskeleton is linked to both the nuclear lamina via LINC complexes and to focal adhesions.This enables the intriguing possibility that forces directly transduced by the nucleus might in fact affect gene expression.Can force transmitted to nucleus and associated alterations to the special organization of genome inside the nucleus modulate gene expression programmes and change cell behaviors? This kind of putative mechanotransduction dominated by the nucleus is termed as nuclear mechanotransduction.Evidence shows that isolated nuclei regulate their stiffness to in response to force applied on nesprin with integrated nuclear lamina and emerin required.Another example is that the force applied on integrins in focal adhesions can be transmitted through actin filaments to the LINC complex and then stretch the chromatin directly through lamina-chromatin interactions.However,the mechanism of nuclear mechanotransduction is still unclear.Three hypotheses have been proposed.The first proposed mechanism is that the proteins on the nuclear lamina are phosphorylated induced by force and their special organization is changed to regulate downstream signal transduction.Transcription factors like YAP and calcium ions would enter the nucleus in the context of force stretching the nuclear lamina and opening nuclear pore complexes(NPC)and calcium channels.Another proposed hypothesis in this case is that force propagated through the cytoskeleton stretches,opens or condenses chromatin directly,leading to an entirely different genome organization.Nevertheless,due to the lack of research methods and instruments,researchers have not reached a consensus on how cells sense external forces and react specifically through nucleus.In this study,we used micropatterned techniques to modify poly(N-isopropyl-acrylamide)(PA)hydrogel surface with fibronectin(FN)which promote cell adhesion to shape-engineer the cells to investigate the effects of matrix stiffness on nuclear mechanotransduction.To illustrate the impact on nuclear shape induced by matrix stiffness,the nuclei were stained byDAPI and observed by a laser confocal microscopy with small step sizes.The nuclear shape index(NSI),which indicate the variation of projected nuclear shape was firstly researched thoroughly.Meanwhile,the nuclear height,width and volume were characterized in this study.To investigate the force transmitted to the nuclei in cells cultured on hydrogels with multiple stiffness,the cell traction force was measured and the cytoskeleton like actin cap was studied by pharmacological treatments.We also found that the impacts of matrix stiffness on nuclear mechanics,which indicated by the condensation of chromatin and the overexpression of Lamin A/C.展开更多
文摘The microstructure and the characteristics of the inclusions embedded in ferrite matrix in simulated coarse-grain heat affected zone (CGHAZ) of a Ti-Zr-treated high strength low alloy (HSLA) steel have been investigated. The microstructure of the simulated CGHAZ dominantly consisted of intragranular acicular ferrite (IAF) combining with a small amount of polygonal ferrite (PF), widmanst tten ferrite (WF), bainite ferrite (BF), pearlite and martensite-austenite (M-A) islands. The PF, WF and BF were generally observed at the prior austenite grain boundaries and the interlocking acicular ferrite was usually found intragranularly. It was found that the inclusions were composed of Ti2O3, ZrO2, Al2O3 locating at the center of the particles and MnS lying on the surface layer of the inclusions. The intragranular complex inclusions promoted the acicular ferrite formation and the refinement of microstructure whilst those at prior austenite grain boundaries caused PF formation on the inclusions. The simulated CGHAZ consisting of such complicated microstructure exhibited desired mechanical properties.
基金This work was supported by a grant from State 863 High Technology R&D Project of China (No. 2001 AA413130) National Natural Science Foundation of China (No.60004001).]
文摘Rehearing furnace is an important device with complex dynamic characteristicsin steel plants. The temperature tracing control of reheating furnace has great importance both tothe quality of slabs and energy saving. A model-based control strategy, multivariable constrainedcontrol (MCC) for the reheating furnace control is used. With this control method, the furnace istreated as a six-input-six-output general model with loops coupled in nature. Compared with thetraditional control, the proposed control strategy gets better temperature tracing accuracy andexhibits some energy saving feature. The simulation results show that the performance of the furnaceis greatly improved.
文摘The oxidation behavior of high speed steel (HSS) was researched by high temperature thermo balance at 500 to 800 °C in water vapor. The morphology was observed by scanning electron microscope, the microstructure of oxide scale was analyzed by energy dispersive spectrometer and X-ray diffraction spectrum. The results indicate that the mass gain of HSS increases with oxidation temperature rising, the effect of oxidation temperature on the morphology is obvious, water vapor temperature only affects mass gain and affects hardly morphology of oxide scale at the same oxidation temperature. The relevant oxidation mechanisms are also discussed.
基金Supported by the National Natural Science Foun-dation of China (60173026) the Ministry of Education Key Project(105071) Foundation of E-Institute of Shanghai HighInstitutions(200301)
文摘A reputation mechanism is introduced in P2P- based Semantic Web to solve the problem of lacking trust. It enables Semantic Web to utilize reputation information based on semantic similarity of peers in the network. This approach is evaluated in a simulation of a content sharing system and the experiments show that the system with reputation mechanism outperforms the system without it.
基金This research was financially supported by the National Natural Science Foundation of China (No.50274028) and the Major StateBasic Research Development Program of China (973 Program No.G19990650).
文摘The oxidation characteristics of high speed steel (HSS) were studied at 500 to 800°C. The non-isothermal oxidation and isothermal oxidation (500, 575, 650, 725, 800°C) of HSS were investigated by thermo-gravimetric analysis (TGA). The microstruc- ture, morphology and oxide scale thickness of the isothermal oxidation samples were analyzed by optical microscope (OM), electron probe micro analyzer (EPMA), X-ray diffraction spectrum (XRD) and scanning electron microscope (SEM). The results indicate that the oxidation rate of HSS is very slow at 500 to 650°C, increasing gradually at 650 to 750°C, and drastically at 750 to 800°C, be- cause the phase transformation happens at about 750°C.
基金Supported by the National863Prugram(2002AA11101)Open Fand of State Teehnology Center uf Mult-media Software Engineering(621-273128)
文摘In this paper,we present a strategy to implement multi-pose face detection in compressed domain.The strategy extracts firstly feature vectors from DCT domain,and then uses a boosting algorithm to build classificrs to distinguish faces and non-faces.Moreover,to get more accurate results of the face detection,we present a kernel function and a linear combination to build incrementally the strong classifiers based on the weak classifiers.Through comparing and analyzing results of some experiments on the synthetic data and the natural data,we can get more satisfied results by the strong classifiers than by the weak classifies.
基金supported by the Foundation for Excellent Youth Scientist of Shandong province(No.03BS105)
文摘A mathematical model describing the behavior of metal inert gas (MIG) welding isformulated in the paper. By means of numerical simulation, the influence of surface-active elements on fluid flow of MIG weldpool is studied. The calculation resultsshow that by adding surface-active elements, the fluid flow behavior is drasticallychanged and the flow fluid flows from lower to upper in vertical direction at the rearof weldpool (w>0). The physical phenomenon is explained from the viewpoint of fluidflow behavior of weldpool that the properties of weld metal is greatly improved andthe content of diffused hydrogen is reduced, thus providing a basis for developing newwelding materials.
文摘The paper describes the recent developing situation and the latest research achievements of refractory for hot metal pretreatment. The relationship among desiliconization, dephosphorization and desulphurization techniques and the main corrosion reactions by various treating agents is analyzed. Some improving measures for several problems in practice are put forward while we anticipate the future developing direction of refractory for hot metal pretreatment.
基金supported by the National Natural Science Foundation of China ( 11522219,11532009)
文摘Cells in vivo reside within a complex microenvironment that is rich in biological,chemical and mechanical cues,playing critical roles in regulating cellular activities(e.g.,proliferation,migration,differentiation)both spatially and temporally.Although it is well accepted that biochemical cues can significantly influence cell functions,accumulating evidence has also shown that mechanical feedback from the cell microenvironment(e.g.,stiffness of ECM,morphology,and tension force)also plays an important role in controlling cell fate.Disequilibrium of the mechanical microenvironment is associated with a series of diseases,such as cancer migration and tissue fibrosis.Thus,there is a pressing need to understand how cells transduce these mechanobiological cues.The cell cytoskeleton is linked to both the nuclear lamina via LINC complexes and to focal adhesions.This enables the intriguing possibility that forces directly transduced by the nucleus might in fact affect gene expression.Can force transmitted to nucleus and associated alterations to the special organization of genome inside the nucleus modulate gene expression programmes and change cell behaviors? This kind of putative mechanotransduction dominated by the nucleus is termed as nuclear mechanotransduction.Evidence shows that isolated nuclei regulate their stiffness to in response to force applied on nesprin with integrated nuclear lamina and emerin required.Another example is that the force applied on integrins in focal adhesions can be transmitted through actin filaments to the LINC complex and then stretch the chromatin directly through lamina-chromatin interactions.However,the mechanism of nuclear mechanotransduction is still unclear.Three hypotheses have been proposed.The first proposed mechanism is that the proteins on the nuclear lamina are phosphorylated induced by force and their special organization is changed to regulate downstream signal transduction.Transcription factors like YAP and calcium ions would enter the nucleus in the context of force stretching the nuclear lamina and opening nuclear pore complexes(NPC)and calcium channels.Another proposed hypothesis in this case is that force propagated through the cytoskeleton stretches,opens or condenses chromatin directly,leading to an entirely different genome organization.Nevertheless,due to the lack of research methods and instruments,researchers have not reached a consensus on how cells sense external forces and react specifically through nucleus.In this study,we used micropatterned techniques to modify poly(N-isopropyl-acrylamide)(PA)hydrogel surface with fibronectin(FN)which promote cell adhesion to shape-engineer the cells to investigate the effects of matrix stiffness on nuclear mechanotransduction.To illustrate the impact on nuclear shape induced by matrix stiffness,the nuclei were stained byDAPI and observed by a laser confocal microscopy with small step sizes.The nuclear shape index(NSI),which indicate the variation of projected nuclear shape was firstly researched thoroughly.Meanwhile,the nuclear height,width and volume were characterized in this study.To investigate the force transmitted to the nuclei in cells cultured on hydrogels with multiple stiffness,the cell traction force was measured and the cytoskeleton like actin cap was studied by pharmacological treatments.We also found that the impacts of matrix stiffness on nuclear mechanics,which indicated by the condensation of chromatin and the overexpression of Lamin A/C.
