The solidification process of a conventional superalloy, IN718, was investigated by confocal scanning laser microscope （CSLM）. The liquid fraction during solidification was obtained as a function of real time and te...The solidification process of a conventional superalloy, IN718, was investigated by confocal scanning laser microscope （CSLM）. The liquid fraction during solidification was obtained as a function of real time and temperature in reference with the in-situ observation. The characteristics of L→γ transformation were analyzed and the γ growing rate of each stage was also calculated. Scheil equation was employed to predict the segregation behavior, and the predict results are in consistence with the experimental results. As a result, the confocal scanning laser microscope shows a great potential for solidification process research.展开更多
To investigate the nucleation behavior during the single-phased metallic solidification process,the commercial ultrapure ferritic stainless steels with no(Initial steel)and various melt treatments(R1,MR1,Y2,MY1,and M1...To investigate the nucleation behavior during the single-phased metallic solidification process,the commercial ultrapure ferritic stainless steels with no(Initial steel)and various melt treatments(R1,MR1,Y2,MY1,and M1 steels)were used to carry out the differential scanning colorimetry(DSC)and high-temperature confocal laser scanning microscope(HT-CLSM)experiments.Based on the results of DSC experiments,the equilibrium solidification process as well as the relationship among the critical undercooling degree(△T_(c)^(DSC)),latent heat of fusion/crystallization(△H_(f)/△H_(c)),equiaxed grain ratio(ER),and average grain size(△_(ave)^(ingot))was revealed.ER is increased with the decreasing△T_(c)^(DSC)and increasing△H_(f)/△H_(c);however,△_(ave)^(ingot)is decreased with them.Referring to the results of HT-CLSM experiments,the average sizes of micro-/macrostructures(d_(ave)/D_(ave)/)are decreased with the increasing cooling rate,as well as the difference between and apparent critical undercooling degree(△T_(c)^(CLSM))was revealed.The heterogeneous nucleation of the crystal nuclei occurs only if△T_(c)^(CLSM)>△T_(c)^(DSC).Combining with the interfacial wetting-lattice mismatch heterogeneous nucleation model,the dynamic mechanism of the metallic solidification was revealed.The as-cast grains of the melt-treated samples were obviously refined,owing to the much higher actual heterogeneous nucleation rates(I_(heter.,i))obtained through melt treatments,and the heterogeneous nucleation rates(I_(heter.,ij))for all samples are increased with the cooling rates,firmly confirming that the as-cast grains of each sample could be refined by the increasing cooling rates.展开更多
To investigate the bacterial colonization on zirconium oxide and titanium surfaces in vivo quantitatively using a confocal laser scanning microscope （CLSM）. Ten samples of zirconium oxide ceramic and commercially pu...To investigate the bacterial colonization on zirconium oxide and titanium surfaces in vivo quantitatively using a confocal laser scanning microscope （CLSM）. Ten samples of zirconium oxide ceramic and commercially pure titanium were fabricated and polished using silicon carbide abrasive paper. One sample from each group was evaluated topographic pattern under a scanning electron microscope. One sample from each group was to evaluate roughness using a profilometer. Eight volunteers were selected. The samples were cemented at the buccal surfaces of upper first molars. All samples were removed after 48 hours, immersed in SYTO-9 and propidium iodide fluorescent to stain for adherent bacteria and obseIved with CLSM. Fewer bacteria were observed in zirconia group than titanium group. However, there was no statistical difference between two groups. The experimental results demonstrate that zirconium oxide may be considered as a promising material for dental implant abutments.展开更多
In this paper, the microstructure change of one step-draw PET fiber has been studied byvarious methods, such as, Laser Raman Microscope, Wide-angle X-ray, Density-gradient andPolarizing Microscope. The computer has be...In this paper, the microstructure change of one step-draw PET fiber has been studied byvarious methods, such as, Laser Raman Microscope, Wide-angle X-ray, Density-gradient andPolarizing Microscope. The computer has been used to resolve overlapped bands in the Ramanspectra. Then the band changes have been correlated with trans, gauche and stressed trans-conformations indicated by a conformational index. Based on these indices, the relationshipbetween the conformation change of glycol units in the fiber structure and the macromechanicalproperties of fiber is expounded.展开更多
A new Quantum Dots（Qdots） nanocrystal composed of semiconductor core and zinc sulfide shell, and its feasibility as labels in immunofluorescence analysis for the imaging of tumor biomarkers by laser scanning confoca...A new Quantum Dots（Qdots） nanocrystal composed of semiconductor core and zinc sulfide shell, and its feasibility as labels in immunofluorescence analysis for the imaging of tumor biomarkers by laser scanning confocal microscope（LSCM） was investigated. Qdots taged by mercaptoacetic acid were conjugated with second antibody, then imaging differences of Heat Shock Proteins 70（HSP70） in renal carcinoma tissure sections with immunofluorescence analysis method using Qdots bioconjugates and conventional organic dye FITC were observed by LSCM to assess the brightness and opticalstability of Qdots. The experimental results showed Qdots bioconjugates achieved the better results in demonstrating HSP70 with more brighter color and more clear picture than FITC labels. Moreover, the label signals of Qdots did not fade clearly after continued exposure to a 488 nm laser for 1 h. The Qdots bioconjugates have good feasibility in immunofluorescence analysis for the bioimaging by LSCM.展开更多
The high-temperature dissolution behavior of primary carbides in samples taken from GCr15 continuous-casting bloom was observed in-situ by confocal laser scanning microscopy.Equations were fitted to the dissolution ki...The high-temperature dissolution behavior of primary carbides in samples taken from GCr15 continuous-casting bloom was observed in-situ by confocal laser scanning microscopy.Equations were fitted to the dissolution kinetics of primary carbides during either heating or soaking.Dissolution of carbides proceeded in three stages(fast→slow→faster)as either temperature or holding time was increased.During the heating process and during the first and third stages of the soaking process,the original size of the carbides determined the steepness of the slope,but during the middle(“slow”)stage of the soaking process,the slope remained zero.The initial size of the carbides varied greatly,but their final dissolution temperature fell within the narrow range of 1210-1235℃,and the holding time remained within 50 min.Fractal analysis was used to study the morphological characteristics of small and medium-sized carbides during the dissolution process.According to changes in the fractal dimension before and after soaking,the carbides tended to evolve towards a more regular morphology.展开更多
The dissolution kinetics of Al_(2)O_(3) in CaO-Al_(2)O_(3) SiOslags was studied using a high-temperature confocal scanning laser microscope at 1773 to 1873 K.The results show that the controlling step during the Al_(2...The dissolution kinetics of Al_(2)O_(3) in CaO-Al_(2)O_(3) SiOslags was studied using a high-temperature confocal scanning laser microscope at 1773 to 1873 K.The results show that the controlling step during the Al_(2)O_(3) dissolution was the diffusionin molten slag.It was found that the dissolution curves of Al_(2)O_(3) particles were hardly agreed with the traditional boundary layer diffusion model with the increase of the CaO/Al_(2)O_(3) ratio of slag.A modified diffusion equation considering slag viscosity was developed to study the dissolution mechanism of Al_(2)O_(3) in slag.Diffusion coefficients of Al_(2)O_(3) in slag were calculated as 2.8×10to 4.1×10m~2/s at the temperature of 1773-1873 K.The dissolution rate of Al_(2)O_(3) increased with higher temperature,CaO/Al_(2)O_(3),and particle size.A new model was shown to be v_(Al_(2)O_(3))=0.16×r_(0)^(1.58)×x^(3.52)×(T-T_(mp))^(1.11)to predict the dissolution rate and the total dissolution time of Al_(2)O_(3) inclusions with various sizes,where vAl_(2)O_(3) is the dissolution rate of Al_(2)O_(3) in volume,μm^(3)/s;x is the value of CaO/Al_(2)O_(3) mass ratio;R_(0) is the initial radius of Al_(2)O_(3),μm;T is the temperature,K;T_(mp) is the melting point of slag,K.展开更多
Taking the mouse as a model, the experimental method of observing the morphology of meiotic spindles and chromosomes in mature oocytes were investigated in order to evaluate the effects of various interventions on the...Taking the mouse as a model, the experimental method of observing the morphology of meiotic spindles and chromosomes in mature oocytes were investigated in order to evaluate the effects of various interventions on the quality of oocytes accurately and rapidly. Laser scanning confocal microscope （LSCM） was used to examine the meiotic spindles and chromosomes by the technologies of optical section and three-dimensional （3D） image reconstruction. The results showed that the configurations of meiotic spindles and chromosomes could be observed clearly by LSCM. The normal rate of meiotic spindles and chromosomes was 82% and 86% respectively. It was concluded that the LSCM was a valid instrument to observe the meiotic spindles and chromosomes of mature oocytes and could be used as a valid method to evaluate the quality of MⅡocytes.展开更多
The dissolution behavior of complex inclusions in refining slag was studied using confocal laser scanning microscope.Based on the dissolution curve of complex inclusions,the main rate-limiting link of CaO-SiO_(2)-Al_(...The dissolution behavior of complex inclusions in refining slag was studied using confocal laser scanning microscope.Based on the dissolution curve of complex inclusions,the main rate-limiting link of CaO-SiO_(2)-Al_(2)O_(3)complex inclusions was the diffusion in the molten slag.The dissolution rate of CaO-SiO_(2)-Al_(2)O_(3)complex inclusions was affected by the composition and size of inclusion.The functional relationship between the dimensionless inclusion capacity(Zh)and the dimensionless dissolution rate(Ry)of CaO-SiO_(2)-Al_(2)O_(3)complex inclusions was calculated as Ry=2.10×10^(-6)Zh^(0.160),while it was Ry=2.10×10^(-6)Zh^(0.0087)for Al_(2)O_(3)-CaO complex inclusions.On this basis,the complete dissolution time and rate of the complex inclusions were calculated by using the function relation between the Zh and Ry numbers.展开更多
Dissolution kinetics of CaO·2Al_(2)O_(3)(CA_(2))particles in a synthetic CaO-Al_(2)O_(3)-SiO_(2)steelmaking slag system have been investigated using the high-temperature confocal laser scanning microscope.Effects...Dissolution kinetics of CaO·2Al_(2)O_(3)(CA_(2))particles in a synthetic CaO-Al_(2)O_(3)-SiO_(2)steelmaking slag system have been investigated using the high-temperature confocal laser scanning microscope.Effects of temperature(i.e.,1500,1550,and 1600℃)and slag composition on the dissolution time of CA_(2)particles are investigated,along with the time dependency of the projection area of the particle during the dissolution process.It is found that the dissolution rate was enhanced by either an increase in temperature or a decrease in slag viscosity.Moreover,a higher ratio of CaO/Al_(2)O_(3)(C/A)leads to an increased dissolution rate of CA_(2)particle at 1600℃.Thermodynamic calculations suggested the dissolution product,i.e.,melilite,formed on the surface of the CA_(2)particle during dissolution in slag with a C/A ratio of 3.8 at 1550℃.Scanning electron microscopy equipped with energy dispersive X-ray spectrometry analysis of as-quenched samples confirmed the dissolution path of CA_(2)particles in slags with C/A ratios of 1.8 and 3.8 as well as the melilite formed on the surface of CA_(2)particle.The formation of this layer during the dissolution process was identified as a hindrance,impeding the dissolution of CA_(2)particle.A valuable reference for designing or/and choosing the composition of top slag for clean steel production is provided,especially using calcium treatment during the secondary refining process.展开更多
The melting and solidification process of DZ411 superalloy at different cooling rates(50,200,500°C/min)was observed in situ by high-temperature confocal laser scanning microscopy.The solidification behaviour of t...The melting and solidification process of DZ411 superalloy at different cooling rates(50,200,500°C/min)was observed in situ by high-temperature confocal laser scanning microscopy.The solidification behaviour of this alloy was also studied through other methods such as differential scanning calorimetry and scanning electron microscopy.The results show that the precipitation sequence of the main phases during the solidification of DZ411 alloy isγmatrix phase,carbide phase and Laves phase.Besides,during the solidification process of DZ411 alloy,both the dendrite thickness and dendrite spacing decreased with the increasing of cooling rate.In addition,a large amount of Ta is enriched in the dendrite stems at the end of solidification,which is the main reason for the formation of Laves phase.As the cooling rate increases,the size of the Laves phase becomes smaller and the distribution becomes more dispersed,which effectively inhibits the segregation of the alloy.展开更多
The strip casts of cobalt-free maraging steel were fabricated using a twin-roll strip casting simulator,and its characteristics of sub-rapid solidification were studied.Subsequently,the confocal laser scanning microsc...The strip casts of cobalt-free maraging steel were fabricated using a twin-roll strip casting simulator,and its characteristics of sub-rapid solidification were studied.Subsequently,the confocal laser scanning microscope(CLSM)was employed to in situ observe the phase transformation during the heat treatment of maraging steel strip cast such as austenitization,solution treatment,and aging processes.It was found that due to the high cooling rate during the twin-roll strip casting process,the sub-rapid solidified strip cast possessed a full lath martensitic structure,weak macrosegregation,and evident microsegregation with a dendritic morphology.During austenitization of strip cast,the austenite grain size increased with the austenitization temperature.After holding at 1250℃for 250 s,the austenite grain size at the high temperature owned a high similarity to the prior austenite grain size of the strip cast,which effectively duplicates the microstructure of the strip cast after sub-rapid solidification.During the solution treatment process,the martensitic structure of the strip cast also underwent austenitic transformation,subsequently transformed into martensite again after quenching.Due to the low reheating temperature during solution treatment,the austenite grain size was refined,resulting in the fine martensitic microstructure after quenching.During the aging process of strip cast,some of martensite transformed into fine austenite,which was located in the interdendritic region and remained stable after air cooling,resulting in the dual-phase microstructure of martensite and austenite.The solute segregation of Ni and Mo elements during the sub-rapid solidification of strip cast caused the enrichment of Ni and Mo elements in the interdendritic region,which can expand the austenite phase region and thus enhance the stability of austenite,leading to the formation of austenite in the interdendritic region after aging treatment.展开更多
The solidification process of AISI 304 stainless steel during cooling at a rate of 0.05 K/s has been observed in situ using a confocal scanning laser microscope （CSLM）. The results show that the 8 phase appeared fir...The solidification process of AISI 304 stainless steel during cooling at a rate of 0.05 K/s has been observed in situ using a confocal scanning laser microscope （CSLM）. The results show that the 8 phase appeared first in liquid steel, as the temperature decreased, the γ phase precipitated prior at δ-grain boundary at 1452. 2 ℃, the liquid steel disappeared at 1 431.3 ℃, and then the γ phase precipitated on the δ ferrite. Based on the Scheil-Gulliver solidification model, the solidification processes of AISI 304 stainless steel are simulated using the Scheil model in Thermo Calc, and the simulation results agree well with the results observed in the experiment.展开更多
This study examined the effect of cholic acid （CA） on cultured cardiac myoeytes （CMs） from neonatal rats with an attempt to explore the possible mechanism of sudden fetal death in intra- hepatic cholestasis of pre...This study examined the effect of cholic acid （CA） on cultured cardiac myoeytes （CMs） from neonatal rats with an attempt to explore the possible mechanism of sudden fetal death in intra- hepatic cholestasis of pregnancy （ICP）. Inverted microscopy was performed to detect the impact of CA on the beating rates of rat CMs. MTT method was used to study the effect of CA on the viability of CMs. CMs cultured in vitro were incubated with 10 ~maol/L Ca2＋-sensitive fluorescence indicator fluo-3/AM. The fluorescence signals of free calcium induced by CA were measured under a laser scanning confocal microscope. The results showed that CA decreased the beating rates of the CMs in a dose-dependent manner. CA could suppress the activities of CMs in a time- and dose-dependent manner. CA increased the concentration of intracellular free calcium in a dose-dependent manner. Our study suggested that CA could inhibit the activity of CMs by causing calcium overload, thereby leading to the sudden fetal death in ICP.展开更多
A zwitterionic nanofiber film was constructed through combining zwitterionic polymer with anodic aluminum oxide template for anti-adhering typical marine corrosive microorganisms,i.e.Pseudomonas aeruginosa,Desulfovibr...A zwitterionic nanofiber film was constructed through combining zwitterionic polymer with anodic aluminum oxide template for anti-adhering typical marine corrosive microorganisms,i.e.Pseudomonas aeruginosa,Desulfovibrio vulgaris and Chaetoceros muelleri.Results showed that the fabricated zwitterionic polymers film has fibrous nanostructure with uniform distribution and super hydrophilia.This film has wide anti-adhering properties,and it can effectively reduce the attachment of these three microorganisms by more than 99%.Moreover,the adhesion of extracellular polymeric substances secreted from these three microorganisms are also inhibited,which is one reason for the fabricated nanofiber film with antiadhesion characteristic of microorganisms.This research provides valuable information for solving the problem of microbial adhesion on metal surfaces in the marine environment.展开更多
To investigate the effect of Myocardin related transcription factor A(MRTF-A)on apoptosis induced by ischemic/reperfusion(I/R),middle cerebral artery occlusion/reperfusion(MCAO/R)in rats were applied to mimic I/R.The ...To investigate the effect of Myocardin related transcription factor A(MRTF-A)on apoptosis induced by ischemic/reperfusion(I/R),middle cerebral artery occlusion/reperfusion(MCAO/R)in rats were applied to mimic I/R.The neurological deficit score,cerebral infarct size,cortical neuron apoptosis and cleaved caspase 3 level were evaluated to determine the effect and the level of apoptosis by TTC straining,terminal deoxynucleotidyl transferase dUTP nick end labeling(TUNEL)straining,Western blot and immunofuorescence staining.The myeloid cell leukemia-1(Mcl-1)expression,release of cytochrome C(Cyt C)and its colocalization with apoptotic pro-tease activating factor-1(Apaf-1)were analyzed by quantitative real-time PCR(qRT-PCR),Western blot,and immunofuorescence staining.The results showed that MRTF-A over-expression could decrease the neurological deficit score and reduce cerebral infarct size(P<0.01 versus Sham).In the MRTF-A-I/R group,TUNEL-positive cells and apoptosis ratio(%)(51.61±6.17%)were significantly decreased compared to the Neg-I/R group(76.45±8.77%)at 24 h reperfusion.Meanwhile,the cleaved caspase 3 expression revealed a similar trend while the expression of Mcl-1 was the opposite.Moreover,MRTF-A overexpression significantly enhanced Mcl-1 fAuorescence intensity,which up-regulated the mRNA and protein level(P<0.05or P<0.01 versus Neg-I/R).Furthermore,MRTF-A overexpression markedly inhibited the release of Cyt C,and decreased the colocalization with Apaf-1 in the cytoplasm(P<0.05 or P<0.01.versus Neg-I/R).All the data indicated that MRTF-A overexpression could improve the neu-rological function against cerebral I/R-induced apoptosis since underlying mechanism might be involved in the Mc-1/Cyt C/cleaved caspase 3 signaling pathway.展开更多
This study was to determine the patterns and levels of IGF family members'expression during postnatal mammary gland development.The authors investigated the protein expression profile of the major components of th...This study was to determine the patterns and levels of IGF family members'expression during postnatal mammary gland development.The authors investigated the protein expression profile of the major components of the IGF axis in murine mammary glands.All the proteins examined,IGF-Ⅰ,IGF-Ⅱ,and IGF-Ⅰreceptor(IGF-ⅠR)were expressed at greatly different levels and displayed unique expression profiles.IGF-Ⅱand IGF-ⅠR were always expressed at significantly higher levels than IGF-Ⅰ.IGF-Ⅰwas localized in adipocytes as well as the epithelial and stromal compartments,but just distinctly expressed where mammary cells aggregated to form ducts,in virgins.The IGF-Ⅱwas localized only on the basal layer epithelial cell membranes of ducts and alveoli,with a peak level on the initiation of lactation.The higher level of IGF-ⅠR compared with IGF-Ⅰwas also found in adipocytes as well as in the epithelial and stromal compartments,especially during pregnancy and late lactation.The IGF-ⅠR pathway was obviously significant for the development of the mammary parenchyma and stroma.Overall,the comparison of the expression profiles of these different proteins would strongly suggest that they were likely to have different functions throughout the mammary gland development,and it also highlighted the potential interactions and coregulation of the members of this axis.It seems that IGF-Ⅱwas the major local modulator rather than IGF-Ⅰby an IGF-ⅠR-independent pathway,especially for initiation of lactation.This study has demonstrated the importance and complexity of the IGF axis during mammary gland development and provides a valuable resource for future research in this area.展开更多
The microstructural changes of Fe83Si4B13 amorphous mother alloy during the heating process were investigated by Laser Scanning Confocal Microscopy （LSCM） ,and the phase transformation was determined by the Thermo-C...The microstructural changes of Fe83Si4B13 amorphous mother alloy during the heating process were investigated by Laser Scanning Confocal Microscopy （LSCM） ,and the phase transformation was determined by the Thermo-Calc calculations. The differences in the melting points measured by Differential Scanning Calorimetry （DSC） and LSCM, and those obtained by Thermo-Calc calculations were also discussed. It is found that the melting points measured by DSC and LSCM are relatively similar, whereas the onset and end of the melting temperatures calculated by Thermo-Calc software are higher than those measured by DSC and observed by LSCM.展开更多
The knife-edge and harmonic technique in the Scanning Laser Acoustic Microscope is studied in this paper. The operating frequency of the SLAM can be increased from 100MHz to 300MHz by using the harmonic technique. The...The knife-edge and harmonic technique in the Scanning Laser Acoustic Microscope is studied in this paper. The operating frequency of the SLAM can be increased from 100MHz to 300MHz by using the harmonic technique. The acoustic images of some samples are obtained on our SLAM at 300MHz.展开更多
Two different kinds of experimental techniques were used to in-situ study the austenite formation during intercritical annealing in C-Mn dual phase steel. The microstructure evolution was observed by confocal laser sc...Two different kinds of experimental techniques were used to in-situ study the austenite formation during intercritical annealing in C-Mn dual phase steel. The microstructure evolution was observed by confocal laser scanning microscope, and the austenite isothermal and non-isothermal transformation kinetics were studied by dilatometry. The results indicate that banded structure is produced for the reason of composition segregation and the competition between recrystallization and phase transformation. Austenite prefers to nucleate not only at ferrite/ferrite grain boundaries, but also inside the grains of ferrite.Furthermore, the austenitizing process is accomplished mainly via migration of the existing austenite/ferrite interface rather than nucleation of new grains. The incubation process can be divided into two stages which are controlled by carbon and manganese diffusion, respectively. During the incubation process, the nucleation rate of austenite decreases, and austenite growth changes from two-dimensional to one-dimensional. The partitioning coefficient, defined as the ratio of manganese content in the austenite to that in the adjacent ferrite, increases with increasing soaking time.展开更多
基金Project(08dj1400402) supported by the Major Program for the Fundamental Research of Shanghai Committee of Science and Technology, China
文摘The solidification process of a conventional superalloy, IN718, was investigated by confocal scanning laser microscope （CSLM）. The liquid fraction during solidification was obtained as a function of real time and temperature in reference with the in-situ observation. The characteristics of L→γ transformation were analyzed and the γ growing rate of each stage was also calculated. Scheil equation was employed to predict the segregation behavior, and the predict results are in consistence with the experimental results. As a result, the confocal scanning laser microscope shows a great potential for solidification process research.
基金supported by the National Natural Science Foundation of China(Grant Nos.52274339,52174321,52074186,and 52104337)Natural Science Foundation of Jiangsu Province(Grant No.BK20231317)China Baowu Low-Carbon Metallurgy Innovation Fund(Grant No.BWLCF202108).
文摘To investigate the nucleation behavior during the single-phased metallic solidification process,the commercial ultrapure ferritic stainless steels with no(Initial steel)and various melt treatments(R1,MR1,Y2,MY1,and M1 steels)were used to carry out the differential scanning colorimetry(DSC)and high-temperature confocal laser scanning microscope(HT-CLSM)experiments.Based on the results of DSC experiments,the equilibrium solidification process as well as the relationship among the critical undercooling degree(△T_(c)^(DSC)),latent heat of fusion/crystallization(△H_(f)/△H_(c)),equiaxed grain ratio(ER),and average grain size(△_(ave)^(ingot))was revealed.ER is increased with the decreasing△T_(c)^(DSC)and increasing△H_(f)/△H_(c);however,△_(ave)^(ingot)is decreased with them.Referring to the results of HT-CLSM experiments,the average sizes of micro-/macrostructures(d_(ave)/D_(ave)/)are decreased with the increasing cooling rate,as well as the difference between and apparent critical undercooling degree(△T_(c)^(CLSM))was revealed.The heterogeneous nucleation of the crystal nuclei occurs only if△T_(c)^(CLSM)>△T_(c)^(DSC).Combining with the interfacial wetting-lattice mismatch heterogeneous nucleation model,the dynamic mechanism of the metallic solidification was revealed.The as-cast grains of the melt-treated samples were obviously refined,owing to the much higher actual heterogeneous nucleation rates(I_(heter.,i))obtained through melt treatments,and the heterogeneous nucleation rates(I_(heter.,ij))for all samples are increased with the cooling rates,firmly confirming that the as-cast grains of each sample could be refined by the increasing cooling rates.
基金Funded by the National Natural Science Foundation of China(No.81271179)the Scientific Research Foundation for Returned Scholars,Ministry of Education of China(No.(2011)1568)the Science and Technology Program of Shanghai Pudong New Area Health Bureau(No.PW2010A-14)
文摘To investigate the bacterial colonization on zirconium oxide and titanium surfaces in vivo quantitatively using a confocal laser scanning microscope （CLSM）. Ten samples of zirconium oxide ceramic and commercially pure titanium were fabricated and polished using silicon carbide abrasive paper. One sample from each group was evaluated topographic pattern under a scanning electron microscope. One sample from each group was to evaluate roughness using a profilometer. Eight volunteers were selected. The samples were cemented at the buccal surfaces of upper first molars. All samples were removed after 48 hours, immersed in SYTO-9 and propidium iodide fluorescent to stain for adherent bacteria and obseIved with CLSM. Fewer bacteria were observed in zirconia group than titanium group. However, there was no statistical difference between two groups. The experimental results demonstrate that zirconium oxide may be considered as a promising material for dental implant abutments.
文摘In this paper, the microstructure change of one step-draw PET fiber has been studied byvarious methods, such as, Laser Raman Microscope, Wide-angle X-ray, Density-gradient andPolarizing Microscope. The computer has been used to resolve overlapped bands in the Ramanspectra. Then the band changes have been correlated with trans, gauche and stressed trans-conformations indicated by a conformational index. Based on these indices, the relationshipbetween the conformation change of glycol units in the fiber structure and the macromechanicalproperties of fiber is expounded.
基金Funded by the National Natural Science Foundation of China (No.303711325)
文摘A new Quantum Dots（Qdots） nanocrystal composed of semiconductor core and zinc sulfide shell, and its feasibility as labels in immunofluorescence analysis for the imaging of tumor biomarkers by laser scanning confocal microscope（LSCM） was investigated. Qdots taged by mercaptoacetic acid were conjugated with second antibody, then imaging differences of Heat Shock Proteins 70（HSP70） in renal carcinoma tissure sections with immunofluorescence analysis method using Qdots bioconjugates and conventional organic dye FITC were observed by LSCM to assess the brightness and opticalstability of Qdots. The experimental results showed Qdots bioconjugates achieved the better results in demonstrating HSP70 with more brighter color and more clear picture than FITC labels. Moreover, the label signals of Qdots did not fade clearly after continued exposure to a 488 nm laser for 1 h. The Qdots bioconjugates have good feasibility in immunofluorescence analysis for the bioimaging by LSCM.
基金supported by Independent Research Project of State Key Laboratory of Advanced Special Steel,Shanghai Key Laboratory of Advanced Ferrometallurgy,Shanghai University(SKLASS-2023-Z13)the Science and Technology Commission of Shanghai Municipality(No.19DZ2270200)+1 种基金A portion of the work was performed at US National High Magnetic Field Laboratory,which is supported by the National Science Foundation(Cooperative Agreement No.DMR-1157490 and DMR-1644779)the State of Florida.Thanks also to Mary Tyler for editing.
文摘The high-temperature dissolution behavior of primary carbides in samples taken from GCr15 continuous-casting bloom was observed in-situ by confocal laser scanning microscopy.Equations were fitted to the dissolution kinetics of primary carbides during either heating or soaking.Dissolution of carbides proceeded in three stages(fast→slow→faster)as either temperature or holding time was increased.During the heating process and during the first and third stages of the soaking process,the original size of the carbides determined the steepness of the slope,but during the middle(“slow”)stage of the soaking process,the slope remained zero.The initial size of the carbides varied greatly,but their final dissolution temperature fell within the narrow range of 1210-1235℃,and the holding time remained within 50 min.Fractal analysis was used to study the morphological characteristics of small and medium-sized carbides during the dissolution process.According to changes in the fractal dimension before and after soaking,the carbides tended to evolve towards a more regular morphology.
基金financially supported by the National Nature Science Foundation of China(Nos.U1860206,51725402)the Science and Technology Program of Hebei,China(Nos.20311006D,20591001D)。
文摘The dissolution kinetics of Al_(2)O_(3) in CaO-Al_(2)O_(3) SiOslags was studied using a high-temperature confocal scanning laser microscope at 1773 to 1873 K.The results show that the controlling step during the Al_(2)O_(3) dissolution was the diffusionin molten slag.It was found that the dissolution curves of Al_(2)O_(3) particles were hardly agreed with the traditional boundary layer diffusion model with the increase of the CaO/Al_(2)O_(3) ratio of slag.A modified diffusion equation considering slag viscosity was developed to study the dissolution mechanism of Al_(2)O_(3) in slag.Diffusion coefficients of Al_(2)O_(3) in slag were calculated as 2.8×10to 4.1×10m~2/s at the temperature of 1773-1873 K.The dissolution rate of Al_(2)O_(3) increased with higher temperature,CaO/Al_(2)O_(3),and particle size.A new model was shown to be v_(Al_(2)O_(3))=0.16×r_(0)^(1.58)×x^(3.52)×(T-T_(mp))^(1.11)to predict the dissolution rate and the total dissolution time of Al_(2)O_(3) inclusions with various sizes,where vAl_(2)O_(3) is the dissolution rate of Al_(2)O_(3) in volume,μm^(3)/s;x is the value of CaO/Al_(2)O_(3) mass ratio;R_(0) is the initial radius of Al_(2)O_(3),μm;T is the temperature,K;T_(mp) is the melting point of slag,K.
文摘Taking the mouse as a model, the experimental method of observing the morphology of meiotic spindles and chromosomes in mature oocytes were investigated in order to evaluate the effects of various interventions on the quality of oocytes accurately and rapidly. Laser scanning confocal microscope （LSCM） was used to examine the meiotic spindles and chromosomes by the technologies of optical section and three-dimensional （3D） image reconstruction. The results showed that the configurations of meiotic spindles and chromosomes could be observed clearly by LSCM. The normal rate of meiotic spindles and chromosomes was 82% and 86% respectively. It was concluded that the LSCM was a valid instrument to observe the meiotic spindles and chromosomes of mature oocytes and could be used as a valid method to evaluate the quality of MⅡocytes.
基金support from the National Key R&D Program(No.2023YFB3709900)the National Natural Science Foundation of China(Grant No.U22A20171)+1 种基金the High Steel Center at the North China University of Technologythe University of Science and Technology Beijing,China.
文摘The dissolution behavior of complex inclusions in refining slag was studied using confocal laser scanning microscope.Based on the dissolution curve of complex inclusions,the main rate-limiting link of CaO-SiO_(2)-Al_(2)O_(3)complex inclusions was the diffusion in the molten slag.The dissolution rate of CaO-SiO_(2)-Al_(2)O_(3)complex inclusions was affected by the composition and size of inclusion.The functional relationship between the dimensionless inclusion capacity(Zh)and the dimensionless dissolution rate(Ry)of CaO-SiO_(2)-Al_(2)O_(3)complex inclusions was calculated as Ry=2.10×10^(-6)Zh^(0.160),while it was Ry=2.10×10^(-6)Zh^(0.0087)for Al_(2)O_(3)-CaO complex inclusions.On this basis,the complete dissolution time and rate of the complex inclusions were calculated by using the function relation between the Zh and Ry numbers.
基金the Natural Sciences and Engineering Research Council of Canada(NSERC)for funding this researchThis research used a high temperature confocal laser scanning microscope-VL2000DX-SVF17SP funded by Canada Foundation for Innovation John Evans Leaders Fund(CFI JELF,Project Number:32826),a PANalytical X’Pert diffraction instrument located at the Centre for crystal growth,Brockhouse Institute for Materials Research,and a scanning electron microscope-JEOL 6610 located at the Canadian Centre for Electron Microscopy at McMaster University.W.Mu would like to acknowledge Swedish Iron and Steel Research Office(Jernkonteret),STINT and SSF for supporting the time for international collaboration research regarding clean steel.
文摘Dissolution kinetics of CaO·2Al_(2)O_(3)(CA_(2))particles in a synthetic CaO-Al_(2)O_(3)-SiO_(2)steelmaking slag system have been investigated using the high-temperature confocal laser scanning microscope.Effects of temperature(i.e.,1500,1550,and 1600℃)and slag composition on the dissolution time of CA_(2)particles are investigated,along with the time dependency of the projection area of the particle during the dissolution process.It is found that the dissolution rate was enhanced by either an increase in temperature or a decrease in slag viscosity.Moreover,a higher ratio of CaO/Al_(2)O_(3)(C/A)leads to an increased dissolution rate of CA_(2)particle at 1600℃.Thermodynamic calculations suggested the dissolution product,i.e.,melilite,formed on the surface of the CA_(2)particle during dissolution in slag with a C/A ratio of 3.8 at 1550℃.Scanning electron microscopy equipped with energy dispersive X-ray spectrometry analysis of as-quenched samples confirmed the dissolution path of CA_(2)particles in slags with C/A ratios of 1.8 and 3.8 as well as the melilite formed on the surface of CA_(2)particle.The formation of this layer during the dissolution process was identified as a hindrance,impeding the dissolution of CA_(2)particle.A valuable reference for designing or/and choosing the composition of top slag for clean steel production is provided,especially using calcium treatment during the secondary refining process.
基金funded by the Key Science and Technology Projects of Gansu Province(Grant No.252DGA006)Central Fund for Guiding Local Science and Technology Development Projects(Grant No.25ZYJB001)+3 种基金Gansu Key Research and Development Project(Grant No.23YFGA0003)Gansu Provincial Joint Research Fund(Grant No.24JRRB004)the Industry support plan of Gansu Universities(Grant No.2024CYZC-01)the Science and Technology Projects of Jiayuguan City(No.24-10,QKJ24-01,QKJ24-10).
文摘The melting and solidification process of DZ411 superalloy at different cooling rates(50,200,500°C/min)was observed in situ by high-temperature confocal laser scanning microscopy.The solidification behaviour of this alloy was also studied through other methods such as differential scanning calorimetry and scanning electron microscopy.The results show that the precipitation sequence of the main phases during the solidification of DZ411 alloy isγmatrix phase,carbide phase and Laves phase.Besides,during the solidification process of DZ411 alloy,both the dendrite thickness and dendrite spacing decreased with the increasing of cooling rate.In addition,a large amount of Ta is enriched in the dendrite stems at the end of solidification,which is the main reason for the formation of Laves phase.As the cooling rate increases,the size of the Laves phase becomes smaller and the distribution becomes more dispersed,which effectively inhibits the segregation of the alloy.
基金supported by National Natural Science Foundation of China(Nos.52130408 and 52304361)Natural Science Foundation of Hunan Province(No.2023JJ40737)the Open Project Program of Anhui Province Key Laboratory of Metallurgical Engineering&Resources Recycling(No.SKF23-02).
文摘The strip casts of cobalt-free maraging steel were fabricated using a twin-roll strip casting simulator,and its characteristics of sub-rapid solidification were studied.Subsequently,the confocal laser scanning microscope(CLSM)was employed to in situ observe the phase transformation during the heat treatment of maraging steel strip cast such as austenitization,solution treatment,and aging processes.It was found that due to the high cooling rate during the twin-roll strip casting process,the sub-rapid solidified strip cast possessed a full lath martensitic structure,weak macrosegregation,and evident microsegregation with a dendritic morphology.During austenitization of strip cast,the austenite grain size increased with the austenitization temperature.After holding at 1250℃for 250 s,the austenite grain size at the high temperature owned a high similarity to the prior austenite grain size of the strip cast,which effectively duplicates the microstructure of the strip cast after sub-rapid solidification.During the solution treatment process,the martensitic structure of the strip cast also underwent austenitic transformation,subsequently transformed into martensite again after quenching.Due to the low reheating temperature during solution treatment,the austenite grain size was refined,resulting in the fine martensitic microstructure after quenching.During the aging process of strip cast,some of martensite transformed into fine austenite,which was located in the interdendritic region and remained stable after air cooling,resulting in the dual-phase microstructure of martensite and austenite.The solute segregation of Ni and Mo elements during the sub-rapid solidification of strip cast caused the enrichment of Ni and Mo elements in the interdendritic region,which can expand the austenite phase region and thus enhance the stability of austenite,leading to the formation of austenite in the interdendritic region after aging treatment.
基金Item Sponsored by National Natural Science Foundation of China(50434040)
文摘The solidification process of AISI 304 stainless steel during cooling at a rate of 0.05 K/s has been observed in situ using a confocal scanning laser microscope （CSLM）. The results show that the 8 phase appeared first in liquid steel, as the temperature decreased, the γ phase precipitated prior at δ-grain boundary at 1452. 2 ℃, the liquid steel disappeared at 1 431.3 ℃, and then the γ phase precipitated on the δ ferrite. Based on the Scheil-Gulliver solidification model, the solidification processes of AISI 304 stainless steel are simulated using the Scheil model in Thermo Calc, and the simulation results agree well with the results observed in the experiment.
基金supported by a grant from Union Hospital,Tongji Medical College,Huazhong University of Science and Technology(No.Union-Grant 02.03.2012-03)
文摘This study examined the effect of cholic acid （CA） on cultured cardiac myoeytes （CMs） from neonatal rats with an attempt to explore the possible mechanism of sudden fetal death in intra- hepatic cholestasis of pregnancy （ICP）. Inverted microscopy was performed to detect the impact of CA on the beating rates of rat CMs. MTT method was used to study the effect of CA on the viability of CMs. CMs cultured in vitro were incubated with 10 ~maol/L Ca2＋-sensitive fluorescence indicator fluo-3/AM. The fluorescence signals of free calcium induced by CA were measured under a laser scanning confocal microscope. The results showed that CA decreased the beating rates of the CMs in a dose-dependent manner. CA could suppress the activities of CMs in a time- and dose-dependent manner. CA increased the concentration of intracellular free calcium in a dose-dependent manner. Our study suggested that CA could inhibit the activity of CMs by causing calcium overload, thereby leading to the sudden fetal death in ICP.
基金financially supported by the National Natural Science Foundation of China(No.41906039)the Key Research and Development Program of Shandong Province(No.2019JZZY010333)the Shandong University Future Plan for Young Scholars and Fundamental Research Funds of Shandong University。
文摘A zwitterionic nanofiber film was constructed through combining zwitterionic polymer with anodic aluminum oxide template for anti-adhering typical marine corrosive microorganisms,i.e.Pseudomonas aeruginosa,Desulfovibrio vulgaris and Chaetoceros muelleri.Results showed that the fabricated zwitterionic polymers film has fibrous nanostructure with uniform distribution and super hydrophilia.This film has wide anti-adhering properties,and it can effectively reduce the attachment of these three microorganisms by more than 99%.Moreover,the adhesion of extracellular polymeric substances secreted from these three microorganisms are also inhibited,which is one reason for the fabricated nanofiber film with antiadhesion characteristic of microorganisms.This research provides valuable information for solving the problem of microbial adhesion on metal surfaces in the marine environment.
基金supported by the National Nature Science Foundation of China(Nos.31171327 and 81770377)the Nature Science Foundation of Hubei Province(No.2017CFB448).
文摘To investigate the effect of Myocardin related transcription factor A(MRTF-A)on apoptosis induced by ischemic/reperfusion(I/R),middle cerebral artery occlusion/reperfusion(MCAO/R)in rats were applied to mimic I/R.The neurological deficit score,cerebral infarct size,cortical neuron apoptosis and cleaved caspase 3 level were evaluated to determine the effect and the level of apoptosis by TTC straining,terminal deoxynucleotidyl transferase dUTP nick end labeling(TUNEL)straining,Western blot and immunofuorescence staining.The myeloid cell leukemia-1(Mcl-1)expression,release of cytochrome C(Cyt C)and its colocalization with apoptotic pro-tease activating factor-1(Apaf-1)were analyzed by quantitative real-time PCR(qRT-PCR),Western blot,and immunofuorescence staining.The results showed that MRTF-A over-expression could decrease the neurological deficit score and reduce cerebral infarct size(P<0.01 versus Sham).In the MRTF-A-I/R group,TUNEL-positive cells and apoptosis ratio(%)(51.61±6.17%)were significantly decreased compared to the Neg-I/R group(76.45±8.77%)at 24 h reperfusion.Meanwhile,the cleaved caspase 3 expression revealed a similar trend while the expression of Mcl-1 was the opposite.Moreover,MRTF-A overexpression significantly enhanced Mcl-1 fAuorescence intensity,which up-regulated the mRNA and protein level(P<0.05or P<0.01 versus Neg-I/R).Furthermore,MRTF-A overexpression markedly inhibited the release of Cyt C,and decreased the colocalization with Apaf-1 in the cytoplasm(P<0.05 or P<0.01.versus Neg-I/R).All the data indicated that MRTF-A overexpression could improve the neu-rological function against cerebral I/R-induced apoptosis since underlying mechanism might be involved in the Mc-1/Cyt C/cleaved caspase 3 signaling pathway.
文摘This study was to determine the patterns and levels of IGF family members'expression during postnatal mammary gland development.The authors investigated the protein expression profile of the major components of the IGF axis in murine mammary glands.All the proteins examined,IGF-Ⅰ,IGF-Ⅱ,and IGF-Ⅰreceptor(IGF-ⅠR)were expressed at greatly different levels and displayed unique expression profiles.IGF-Ⅱand IGF-ⅠR were always expressed at significantly higher levels than IGF-Ⅰ.IGF-Ⅰwas localized in adipocytes as well as the epithelial and stromal compartments,but just distinctly expressed where mammary cells aggregated to form ducts,in virgins.The IGF-Ⅱwas localized only on the basal layer epithelial cell membranes of ducts and alveoli,with a peak level on the initiation of lactation.The higher level of IGF-ⅠR compared with IGF-Ⅰwas also found in adipocytes as well as in the epithelial and stromal compartments,especially during pregnancy and late lactation.The IGF-ⅠR pathway was obviously significant for the development of the mammary parenchyma and stroma.Overall,the comparison of the expression profiles of these different proteins would strongly suggest that they were likely to have different functions throughout the mammary gland development,and it also highlighted the potential interactions and coregulation of the members of this axis.It seems that IGF-Ⅱwas the major local modulator rather than IGF-Ⅰby an IGF-ⅠR-independent pathway,especially for initiation of lactation.This study has demonstrated the importance and complexity of the IGF axis during mammary gland development and provides a valuable resource for future research in this area.
文摘The microstructural changes of Fe83Si4B13 amorphous mother alloy during the heating process were investigated by Laser Scanning Confocal Microscopy （LSCM） ,and the phase transformation was determined by the Thermo-Calc calculations. The differences in the melting points measured by Differential Scanning Calorimetry （DSC） and LSCM, and those obtained by Thermo-Calc calculations were also discussed. It is found that the melting points measured by DSC and LSCM are relatively similar, whereas the onset and end of the melting temperatures calculated by Thermo-Calc software are higher than those measured by DSC and observed by LSCM.
文摘The knife-edge and harmonic technique in the Scanning Laser Acoustic Microscope is studied in this paper. The operating frequency of the SLAM can be increased from 100MHz to 300MHz by using the harmonic technique. The acoustic images of some samples are obtained on our SLAM at 300MHz.
基金Project(2013AA031601)supported by the National High Technology Research and Development Program of ChinaProject(2012BAF04B01)supported by the National Science and Technology Pillar Program During the 12th Five-year Plan Period of China
文摘Two different kinds of experimental techniques were used to in-situ study the austenite formation during intercritical annealing in C-Mn dual phase steel. The microstructure evolution was observed by confocal laser scanning microscope, and the austenite isothermal and non-isothermal transformation kinetics were studied by dilatometry. The results indicate that banded structure is produced for the reason of composition segregation and the competition between recrystallization and phase transformation. Austenite prefers to nucleate not only at ferrite/ferrite grain boundaries, but also inside the grains of ferrite.Furthermore, the austenitizing process is accomplished mainly via migration of the existing austenite/ferrite interface rather than nucleation of new grains. The incubation process can be divided into two stages which are controlled by carbon and manganese diffusion, respectively. During the incubation process, the nucleation rate of austenite decreases, and austenite growth changes from two-dimensional to one-dimensional. The partitioning coefficient, defined as the ratio of manganese content in the austenite to that in the adjacent ferrite, increases with increasing soaking time.
