In the present investigation, a coupled crystal plasticity finite-element(CPFE) and cellular automaton(CA) model was developed to predict the microstructure of recrystallization in single-crystal(SX) Ni-based superall...In the present investigation, a coupled crystal plasticity finite-element(CPFE) and cellular automaton(CA) model was developed to predict the microstructure of recrystallization in single-crystal(SX) Ni-based superalloy.The quasi-static compressive tests of [001] orientated SX DD6 superalloy were conducted on Gleeble3500 tester to calibrate the CPFE model based on crystal slip kinematics.The simulated stress-strain curve agrees well with the experimental results. Quantitative deformation amount was introduced in the deformed samples of simulation and experiment, and these samples were subsequently subjected to the standard solution heat treatment(SSHT).Results of CA simulation show that the recrystallization(RX) nucleation tends to occur at the third stage of SSHT process due to the high critical temperature of RX nucleation for the samples deformed at room temperature. The inhomogeneous RX grains gradually coarsen and compete to reach more stable status by reducing the system energy.Simulated RX grain density decreases from 7.500 to1.875 mm,agreeing well with the value of 1.920 mmfrom electron backscattered diffraction(EBSD) detection of the experimental sample.展开更多
It is clarified by experimental examination and theoretical analysis that the transformation of crystal moorphology of the eutectic Al-Cu alloy composite-in-situ seems to be judged by not only the constitutional super...It is clarified by experimental examination and theoretical analysis that the transformation of crystal moorphology of the eutectic Al-Cu alloy composite-in-situ seems to be judged by not only the constitutional supercooling proposed in previous literatures but also the supercooling due to the effect of curved surfaces at the solidifying from.The greater entropy of fusion and the tendency to faceted face are important features of the non-metallic phase,which may con- tribute to the leading,role of the phase during solidification.It might be the change of leading phase that changes the morphology of crystals.展开更多
Dinoflagellates nuclei allow for liquid crystalline characterization without core histones. In this study, nuclei were isolated from the athecate Karenia dinoflagellate species with minimum destruction to their native...Dinoflagellates nuclei allow for liquid crystalline characterization without core histones. In this study, nuclei were isolated from the athecate Karenia dinoflagellate species with minimum destruction to their native structure during preparation procedures. The liquid crystalline nuclei were studied by microscopy techniques of Metripol birefringence microscopy, Confocal Laser Scanning Microscopy (CLSM) and synchrotron radiation-based hard X-ray Microscopy with computed tomography, respectively. The 3D reconstruction techniques of hard X-ray tomography and CLSM were also discussed. The important biophysical parameters of the interspaces between chromosomes, nuclear surface areas and chromosome-occupied volumes were calculated from a 3D rendering of a reconstructed nucleus. The results of calculated average chromosomal DNA concentration of dinoflagellate was consistent with the concentration which can spontaneously assemble into the cholesteric liquid crystal phase in vitro.展开更多
A new numerical model is developed using a Cellular Automata (CA) method to study the liquid-phase dissolution behavior of gap-filler powder particles in interlayer powder mixture during transient liquid phase (TLP) b...A new numerical model is developed using a Cellular Automata (CA) method to study the liquid-phase dissolution behavior of gap-filler powder particles in interlayer powder mixture during transient liquid phase (TLP) bonding process. The model prediction of microstructural evolution in TLP joint between single crystal substrates show that formation of misoriented stray-grains results from incomplete liquation of the gap-filler powder particles. In contrast to what is generally assumed and reported, numerical calculations coupled with experimental verification show that under properly selected process parameters, complete melting of the gap-filler powder particles is possible. This is imperative to prevent the formation of misoriented stray-grains and maintain single crystallinity during TLP bonding of single crystal materials. The dependence of complete melting of the gap-filler particles on salient TLP bonding parameters are analyzed and discussed.展开更多
This paper deals with the technology of computer graphics and its application in ana-lyzing complex nonlinear proceas. We have investigated metal crystallization, which is a complexnonlinear process and is difficult t...This paper deals with the technology of computer graphics and its application in ana-lyzing complex nonlinear proceas. We have investigated metal crystallization, which is a complexnonlinear process and is difficult to analyze by using the conventional numerical rnethod to estab-lish a complete and accurate mathematical modcl. Based on the principles of metal crystallizationand Cellular Automata algorithm, the author separated, in time and space, the process ofccystailization into periodically growing airays, so that the simulation of metal crystallization isrealized.展开更多
Solidification structure is critical in the control of the mechanical properties and quality during the continuous casting process. The thermo-physical properties of 13 Cr steel added some rare metals, such as Mo, V, ...Solidification structure is critical in the control of the mechanical properties and quality during the continuous casting process. The thermo-physical properties of 13 Cr steel added some rare metals, such as Mo, V, Nb, are measured to better understand the solidification structure of 13 Cr bloom. A computational model using CA-FE(cellular automation-finite element) method coupled with heat transfer model is developed to describe the solidification structure in continuous casting process. It is found that the calculated solidification structure is in good agreement with the observed data. The influence of casting speed and superheat on the solidification structure of the bloom is studied in detail. In order to obtain more equiaxed crystal ratio and low degree of the segregation in the bloom, the optimized casting speed 0.6 m/min and superheat less than 25 °C are determined for the caster. Using the optimized manufacturing parameters, these samples are 60% with the equiaxed zone ratio of 8%–10% and below the degree of segregation 1.05.展开更多
With the growing importance of the black soldier fly(Hermetia illucens)for both sustainable food production and waste management as well as for science,a great demand of understanding its immune system arises.Here,we ...With the growing importance of the black soldier fly(Hermetia illucens)for both sustainable food production and waste management as well as for science,a great demand of understanding its immune system arises.Here,we present the first description of the circulating larval hemocytes with special emphasis on uptake of microorganisms and distinguishing hemocyte types.With histological,zymographic,and cytometric methods and with a set of hemocyte binding lectins and antibodies,the hemocytes of H.illucens are identified as plasmatocytes,crystal cells,and putative prohemocytes.Total hemocyte counts(THC)are determined,and methods for THC determination are compared.Approximately 1100 hemocytes per microliter hemolymph are present in naive animals,while hemocyte density decreases dramatically shortly after wounding,indicating a role of hemocytes in response to wounding(and immune response in general).The determination of the relative abundance of each hemocyte type(differential hemocyte count,DHC)revealed that plasmatocytes are highly abundant,whereas prohemocytes and crystal cells make up only a small percentage of the circulating cells.Plasmatocytes are not only the most abundant but also the professional phagocytes in H.illucens.They rapidly engulf and take up bacteria both in vivo and in vitro,indicating a very potent cellular defense against invading pathogens.Larger bioparticles such as yeasts are also removed from circulation by phagocytosis,but slower than bacteria.This is the first analysis of the potent cellular immune response in the black soldier fly,and a first toolbox that helps to identify hemocyte(types)is presented.展开更多
基金financially supported by the National Key R&D Program of China (No.2017YFB0701503)the National Basic Research Program of China(No.2011CB706801)
文摘In the present investigation, a coupled crystal plasticity finite-element(CPFE) and cellular automaton(CA) model was developed to predict the microstructure of recrystallization in single-crystal(SX) Ni-based superalloy.The quasi-static compressive tests of [001] orientated SX DD6 superalloy were conducted on Gleeble3500 tester to calibrate the CPFE model based on crystal slip kinematics.The simulated stress-strain curve agrees well with the experimental results. Quantitative deformation amount was introduced in the deformed samples of simulation and experiment, and these samples were subsequently subjected to the standard solution heat treatment(SSHT).Results of CA simulation show that the recrystallization(RX) nucleation tends to occur at the third stage of SSHT process due to the high critical temperature of RX nucleation for the samples deformed at room temperature. The inhomogeneous RX grains gradually coarsen and compete to reach more stable status by reducing the system energy.Simulated RX grain density decreases from 7.500 to1.875 mm,agreeing well with the value of 1.920 mmfrom electron backscattered diffraction(EBSD) detection of the experimental sample.
文摘It is clarified by experimental examination and theoretical analysis that the transformation of crystal moorphology of the eutectic Al-Cu alloy composite-in-situ seems to be judged by not only the constitutional supercooling proposed in previous literatures but also the supercooling due to the effect of curved surfaces at the solidifying from.The greater entropy of fusion and the tendency to faceted face are important features of the non-metallic phase,which may con- tribute to the leading,role of the phase during solidification.It might be the change of leading phase that changes the morphology of crystals.
文摘Dinoflagellates nuclei allow for liquid crystalline characterization without core histones. In this study, nuclei were isolated from the athecate Karenia dinoflagellate species with minimum destruction to their native structure during preparation procedures. The liquid crystalline nuclei were studied by microscopy techniques of Metripol birefringence microscopy, Confocal Laser Scanning Microscopy (CLSM) and synchrotron radiation-based hard X-ray Microscopy with computed tomography, respectively. The 3D reconstruction techniques of hard X-ray tomography and CLSM were also discussed. The important biophysical parameters of the interspaces between chromosomes, nuclear surface areas and chromosome-occupied volumes were calculated from a 3D rendering of a reconstructed nucleus. The results of calculated average chromosomal DNA concentration of dinoflagellate was consistent with the concentration which can spontaneously assemble into the cholesteric liquid crystal phase in vitro.
文摘A new numerical model is developed using a Cellular Automata (CA) method to study the liquid-phase dissolution behavior of gap-filler powder particles in interlayer powder mixture during transient liquid phase (TLP) bonding process. The model prediction of microstructural evolution in TLP joint between single crystal substrates show that formation of misoriented stray-grains results from incomplete liquation of the gap-filler powder particles. In contrast to what is generally assumed and reported, numerical calculations coupled with experimental verification show that under properly selected process parameters, complete melting of the gap-filler powder particles is possible. This is imperative to prevent the formation of misoriented stray-grains and maintain single crystallinity during TLP bonding of single crystal materials. The dependence of complete melting of the gap-filler particles on salient TLP bonding parameters are analyzed and discussed.
文摘This paper deals with the technology of computer graphics and its application in ana-lyzing complex nonlinear proceas. We have investigated metal crystallization, which is a complexnonlinear process and is difficult to analyze by using the conventional numerical rnethod to estab-lish a complete and accurate mathematical modcl. Based on the principles of metal crystallizationand Cellular Automata algorithm, the author separated, in time and space, the process ofccystailization into periodically growing airays, so that the simulation of metal crystallization isrealized.
基金Projects(51274057,51474057) supported by the National Natural Science Foundation of ChinaProject(2012AA03A508) supported by the High-tech Research and Development Program of China
文摘Solidification structure is critical in the control of the mechanical properties and quality during the continuous casting process. The thermo-physical properties of 13 Cr steel added some rare metals, such as Mo, V, Nb, are measured to better understand the solidification structure of 13 Cr bloom. A computational model using CA-FE(cellular automation-finite element) method coupled with heat transfer model is developed to describe the solidification structure in continuous casting process. It is found that the calculated solidification structure is in good agreement with the observed data. The influence of casting speed and superheat on the solidification structure of the bloom is studied in detail. In order to obtain more equiaxed crystal ratio and low degree of the segregation in the bloom, the optimized casting speed 0.6 m/min and superheat less than 25 °C are determined for the caster. Using the optimized manufacturing parameters, these samples are 60% with the equiaxed zone ratio of 8%–10% and below the degree of segregation 1.05.
基金We wish to thank Prof.Herwig Gutzeit for valuable discussions and providing antibody stocks.We would like to express our gratitude to Dr.Alexander Froschauer and Prof.Klaus Reinhardt who hosted the work in their laboratories,to Prof.Thorsten Mascher and Prof.Christian Dahmann for allowing us to use their laboratory equipment,and Dr.Diana Wolf who provided bacteria strains.We thank Dr.Uwe Töpfer for valuable discussions and assistance in microscopy,Dennis Höfling for Hermetia breeding,and Katharina Starke,Yvonne Henker and Christin Froschauer for assistance in the laboratory.We thank the two anonymous reviewers for their helpful comments that improved the quality of the manuscript significantly.
文摘With the growing importance of the black soldier fly(Hermetia illucens)for both sustainable food production and waste management as well as for science,a great demand of understanding its immune system arises.Here,we present the first description of the circulating larval hemocytes with special emphasis on uptake of microorganisms and distinguishing hemocyte types.With histological,zymographic,and cytometric methods and with a set of hemocyte binding lectins and antibodies,the hemocytes of H.illucens are identified as plasmatocytes,crystal cells,and putative prohemocytes.Total hemocyte counts(THC)are determined,and methods for THC determination are compared.Approximately 1100 hemocytes per microliter hemolymph are present in naive animals,while hemocyte density decreases dramatically shortly after wounding,indicating a role of hemocytes in response to wounding(and immune response in general).The determination of the relative abundance of each hemocyte type(differential hemocyte count,DHC)revealed that plasmatocytes are highly abundant,whereas prohemocytes and crystal cells make up only a small percentage of the circulating cells.Plasmatocytes are not only the most abundant but also the professional phagocytes in H.illucens.They rapidly engulf and take up bacteria both in vivo and in vitro,indicating a very potent cellular defense against invading pathogens.Larger bioparticles such as yeasts are also removed from circulation by phagocytosis,but slower than bacteria.This is the first analysis of the potent cellular immune response in the black soldier fly,and a first toolbox that helps to identify hemocyte(types)is presented.
