In this study,the effects of Eu addition on the microstructures and mechanical properties of A390 alloy were investigated,along with the spheroidization mechanism of primary silicon with Eu.The results showed that whe...In this study,the effects of Eu addition on the microstructures and mechanical properties of A390 alloy were investigated,along with the spheroidization mechanism of primary silicon with Eu.The results showed that when the Eu addition reached 0.6 wt%,both refinement and spheroidization of primary silicon,alongside fibrous eutectic silicon can be obtained.Owing to such a microstructural modification,the ultimate tensile strength and elongation were increased by 24.9%and 101.2%,respectively.While in the unmodified alloy,the octahedral,plate-like,and five-star primary silicon particles exhibited fewΣ3 twin boundaries,whereas in the Eu-modified alloy,spheroidal primary silicon displayed curvedΣ3 twin boundaries,sub-grain boundaries,and specialΣ9 twin boundaries.Atom probe tomography analysis indicated that Al and Eu atoms were present in the spheroidal primary silicon as spheroidal,T-shaped,straight rod-like,and curved rod-like clusters,with the Al:Eu ratio of 2.92±0.46.The spheroidization mechanism of primary silicon was proposed through five aspects:(ⅰ)spheroidal clusters inducing parallel and intersectingΣ3 twins,(ⅱ)straight rod-like clusters causing poisoning of twin plane re-entrant edge,(ⅲ)T-shaped clusters leading to multithickness intersectingΣ3 twins,(ⅳ)curved rod-like clusters resulting in curvedΣ3 twins,and(ⅴ)curved rod-like clusters induce specialΣ9 twins.These mechanisms facilitate a transition from initially anisotropic to isotropic growth of primary silicon with Eu addition.The present work provides an important insight for the development of a novel way to achieve the primary Si spheroidization and the improvement of mechanical properties of hypereutectic Al-Si alloys.展开更多
The development of a new generation of high-performance Al alloys,achieved through Sc/Zr-modified Al-Mg-based alloys,is attracting growing attention.However,the significant cost associated with Sc presents a barrier t...The development of a new generation of high-performance Al alloys,achieved through Sc/Zr-modified Al-Mg-based alloys,is attracting growing attention.However,the significant cost associated with Sc presents a barrier to further advancement.In this study,the inclusion of trace heterogeneous TiB_(2)particles is employed to regulate the microstructural evolution process,thereby achieving high-performance aluminum alloys with optimal strength-ductility characteristics with minimal Sc addition.The ultimate tensile strength of Al-Mg-Sc-Zr-TiB_(2)alloy reached 442.4 MPa,with a elongation of 16.6%.The combined impact of TiB_(2)particles and Al_(3)(Sc,Zr)precipitates on the microstructure evolution of the Al-Mg alloy during hot deformation was investigated.It was observed that spherical Al_(3)(Sc,Zr)precipitates with sizes ranging from 5 to 10 nm dispersed in the matrix,during the hot deformation process,functioned as Zener pinning sites for dislocations,thus increasing the proportion of low-angle grain boundaries(LAGBs)and suppressing the dynamic recrystallization(DRX)process.The incorporation of trace TiB_(2)particles induced the particle-stimulated nucleation effect,accelerating DRX and refining the microstructure.The density of LAGBs further increased,and the proportion of continuous dynamic recrystallization also rose.Furthermore,the TiB_(2)particles mitigated the anisotropy of material and inhibited DRX grain growth,thereby expanding the subsequent processing window and offering more potential applications for the materials.This study provides new insights into the production of high-performance Al alloy products.展开更多
A nonionic waterborne polyurethane(WPU) was synthesized by the self-emulsification method using polyether diol(N220),isophorone diisocyanate(IPDI),trimethylolpropane poly(ethylene glycol monomethyl ether)(N120),1,4-bu...A nonionic waterborne polyurethane(WPU) was synthesized by the self-emulsification method using polyether diol(N220),isophorone diisocyanate(IPDI),trimethylolpropane poly(ethylene glycol monomethyl ether)(N120),1,4-butanediol(BDO) and trimethylolpropane(TMP) as the main materials.The effects of the NCO/OH ratio on the emulsion and film properties of NWPU were explored.The experimental results show that the NWPU prepared at an NCO/OH ratio of 1.1 has good emulsion stability and easy film formation,and the resultant film was elastic,soft,and transparent.The sample was used for wool finishing and the application performance was evaluated.When the NWPU dosage reached 40 g·L^(-1),the fabric area felt shrinkage rate reduced from 8.97% to 4.75%,the pilling rating raised from grade 2-3 to grade 4,and the whiteness value only decreased by 3.87%.展开更多
BACKGROUNI）： Hepatocellular adenoma （HCA） is a rare benign tumor of the liver. It is of clinical importance to dif- ferentiate HCA from other liver tumors, especially hepatocel- lular carcinoma （HCC）. This study...BACKGROUNI）： Hepatocellular adenoma （HCA） is a rare benign tumor of the liver. It is of clinical importance to dif- ferentiate HCA from other liver tumors, especially hepatocel- lular carcinoma （HCC）. This study aimed to evaluate the char- acteristic features of HCA by conventional ultrasound and contrast-enhanced ultrasound （CEUS） findings. METHODS： Twenty-six patients （10 males and 16 females; mean age 36.2＋5.0 years） with 26 histopathologically proven HCAs were retrospectively identified. According to the maxi- mum diameter of HCAs, they were divided into three groups： 〈30 mm, 30-50 mm, and 〉50 mm. Ultrasound examinations were performed with C5-2 broadband curved transducer of Philips iU22 unit （Philips Bothell, WA, USA）. For each lesion, a dose of 2.4 mL SonoVue~ （Bracco Imaging Spa, Milan, Italy） was injected as a quick bolus into the cubital vein. Lesions＇ echogenicity, color-Doppler flow imaging and contrast en- hancement patterns were recorded. RESULTS： Grayscale ultrasound revealed that most of HCAs were hypoechoic （73.1%, 19/26）. Spotty calcifications were detected in 26.9% （7/26） of the lesions. Color-Doppler flow imaging detected centripetal bulky color flow in 46.2% （12/26） of the HCAs. CEUS showed that 73.1% （19/26） of the HCAs displayed as rapid, complete and homogenous enhancement, and 53.8% （14/26） showed decreased contrast enhancement in the late phase. There was no significant difference in enhance- ment patterns among different sizes of HCAs （P〉0.05）. Centripetal enhancement with subcapsular tortuous arteries was common in larger HCAs.展开更多
Objective To assess recent trends and prognostic features in the treatment of pure mucinous carcinoma(PMC) of the breast.Methods Fifty-six patients diagnosed with PMC of the breast in our hospital from December 1982 t...Objective To assess recent trends and prognostic features in the treatment of pure mucinous carcinoma(PMC) of the breast.Methods Fifty-six patients diagnosed with PMC of the breast in our hospital from December 1982 to June 2008 were included.We evaluated the general information and tumor characteristics of the patients,examined the relationship between these factors and prognosis.Fisher's exact test was applied to analyze tumor characteristics.Results The mean age of the patients was 53.7 years.The majority of the patients presented with early stage disease.Tumor size was found not a significant prognostic factor in this study.Mean follow-up period was 39 months and no breast cancer-related deaths were identified in the patient cohort.Conclusions PMC of the breast has a favorable prognosis.Tumor size does not appear to significantly impact survival.展开更多
Three-layer6009/7050/6009aluminum alloy clad slab was fabricated by an innovative direct-chill casting process.To study the response of the clad slab to plastic deformation and heat treatments,homogenization annealing...Three-layer6009/7050/6009aluminum alloy clad slab was fabricated by an innovative direct-chill casting process.To study the response of the clad slab to plastic deformation and heat treatments,homogenization annealing,hot rolling,solution and aging were successively performed on the as-cast6009/7050/6009clad samples.The results revealed that excellent metallurgical bonding between7050alloy layer and6009alloy layer was achieved under optimal parameters.The clad ratio obviously decreased when the annealed sample was rolled to55%hot reduction level,and then changed slightly with further rolling.Furthermore,the content of rodlike Zn-rich phases increased significantly in7050alloy layer in the homogenized clad samples after rolling at55%,65%and75%hot reduction levels,and the higher level of hot reduction resulted in narrower diffusion layer.Subsequent solution and aging significantly improved the hardness in7050alloy layer,interfaces and6009alloy layers of the rolled samples except for the thin side for the75%hot reduction sample.展开更多
By Green＇s function method we show that the water hammer （WH） can be analytically predicted for both laminar and turbulent flows （for the latter, with an eddy vis- cosity depending solely on the space coordinates...By Green＇s function method we show that the water hammer （WH） can be analytically predicted for both laminar and turbulent flows （for the latter, with an eddy vis- cosity depending solely on the space coordinates）, and thus its hazardous effect can be rationally controlled and mini- mized. To this end, we generalize a laminar water hammer equation of Wang et al. （J. Hydrodynamics, B2, 51, 1995） to include arbitrary initial condition and variable viscosity, and obtain its solution by Green＇s function method. The pre- dicted characteristic WH behaviors by the solutions are in excellent agreement with both direct numerical simulation of the original governing equations and, by adjusting the eddy viscosity coefficient, experimentally measured turbulent flow data. Optimal WH control principle is thereby constructed and demonstrated.展开更多
This work attempts to extend the fundamental theory for classic gas dynamics to viscous compressible flow,of which aeroacoustics will naturally be a special branch.As a continuation of Part I.Unbounded fluid(Mao et al...This work attempts to extend the fundamental theory for classic gas dynamics to viscous compressible flow,of which aeroacoustics will naturally be a special branch.As a continuation of Part I.Unbounded fluid(Mao et al.,2022),this paper studies the source of longitudinal field at solid boundary,caused by the on-wall kinematic and viscous dynamic coupling of longitudinal and transverse processes.We find that at this situation the easiest choice for the two independent thermodynamic variables is the dimensionless pressure P and temperature T.The two-level structure of boundary dynamics of longitudinal field is obtained by applying the continuity equation and its normal derivative to the surface.We show that the boundary dilatation flux represents faithfully the boundary production of vortex sound and entropy sound,and the mutual generation mechanism of the longitudinal and transverse fields on the boundary does not occur symmetrically"at the samc level,but appears along a zigzag route.At the first level,it is the pressure gradient that generates vorticity unidirectionally;while at the second level,it is the vorticity that generates dilatation unidirectionally.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.52301046,U24A2028 and U22A20174)the Program for Science&Technology Innovation Talents in Universities of Henan Province(25HASTIT007)+2 种基金the Frontier Exploration Projects of Longmen Laboratory(No.LMQYT-SKT005)the Central Plains Talents Planthe support of Provincial and Ministerial Co-construction of Collaborative Innovation Center for Non-ferrous Metal New Materials and Advanced Processing Technology
文摘In this study,the effects of Eu addition on the microstructures and mechanical properties of A390 alloy were investigated,along with the spheroidization mechanism of primary silicon with Eu.The results showed that when the Eu addition reached 0.6 wt%,both refinement and spheroidization of primary silicon,alongside fibrous eutectic silicon can be obtained.Owing to such a microstructural modification,the ultimate tensile strength and elongation were increased by 24.9%and 101.2%,respectively.While in the unmodified alloy,the octahedral,plate-like,and five-star primary silicon particles exhibited fewΣ3 twin boundaries,whereas in the Eu-modified alloy,spheroidal primary silicon displayed curvedΣ3 twin boundaries,sub-grain boundaries,and specialΣ9 twin boundaries.Atom probe tomography analysis indicated that Al and Eu atoms were present in the spheroidal primary silicon as spheroidal,T-shaped,straight rod-like,and curved rod-like clusters,with the Al:Eu ratio of 2.92±0.46.The spheroidization mechanism of primary silicon was proposed through five aspects:(ⅰ)spheroidal clusters inducing parallel and intersectingΣ3 twins,(ⅱ)straight rod-like clusters causing poisoning of twin plane re-entrant edge,(ⅲ)T-shaped clusters leading to multithickness intersectingΣ3 twins,(ⅳ)curved rod-like clusters resulting in curvedΣ3 twins,and(ⅴ)curved rod-like clusters induce specialΣ9 twins.These mechanisms facilitate a transition from initially anisotropic to isotropic growth of primary silicon with Eu addition.The present work provides an important insight for the development of a novel way to achieve the primary Si spheroidization and the improvement of mechanical properties of hypereutectic Al-Si alloys.
基金supported by the National Key Research and Development Program of China(No.2022YFB3400142)the National Natural Science Foundation of China(Nos.52174356,51971051 and U22A20174)+2 种基金the Science and Technology Plan Project of Liaoning Province(Nos.2022010005-JH6/1001 and 2022JH2/1013)the Major Science and Technology Projects of Longmen Laboratory(No.231100220400)the Fundamental Research Funds for the Central Universities.
文摘The development of a new generation of high-performance Al alloys,achieved through Sc/Zr-modified Al-Mg-based alloys,is attracting growing attention.However,the significant cost associated with Sc presents a barrier to further advancement.In this study,the inclusion of trace heterogeneous TiB_(2)particles is employed to regulate the microstructural evolution process,thereby achieving high-performance aluminum alloys with optimal strength-ductility characteristics with minimal Sc addition.The ultimate tensile strength of Al-Mg-Sc-Zr-TiB_(2)alloy reached 442.4 MPa,with a elongation of 16.6%.The combined impact of TiB_(2)particles and Al_(3)(Sc,Zr)precipitates on the microstructure evolution of the Al-Mg alloy during hot deformation was investigated.It was observed that spherical Al_(3)(Sc,Zr)precipitates with sizes ranging from 5 to 10 nm dispersed in the matrix,during the hot deformation process,functioned as Zener pinning sites for dislocations,thus increasing the proportion of low-angle grain boundaries(LAGBs)and suppressing the dynamic recrystallization(DRX)process.The incorporation of trace TiB_(2)particles induced the particle-stimulated nucleation effect,accelerating DRX and refining the microstructure.The density of LAGBs further increased,and the proportion of continuous dynamic recrystallization also rose.Furthermore,the TiB_(2)particles mitigated the anisotropy of material and inhibited DRX grain growth,thereby expanding the subsequent processing window and offering more potential applications for the materials.This study provides new insights into the production of high-performance Al alloy products.
文摘A nonionic waterborne polyurethane(WPU) was synthesized by the self-emulsification method using polyether diol(N220),isophorone diisocyanate(IPDI),trimethylolpropane poly(ethylene glycol monomethyl ether)(N120),1,4-butanediol(BDO) and trimethylolpropane(TMP) as the main materials.The effects of the NCO/OH ratio on the emulsion and film properties of NWPU were explored.The experimental results show that the NWPU prepared at an NCO/OH ratio of 1.1 has good emulsion stability and easy film formation,and the resultant film was elastic,soft,and transparent.The sample was used for wool finishing and the application performance was evaluated.When the NWPU dosage reached 40 g·L^(-1),the fabric area felt shrinkage rate reduced from 8.97% to 4.75%,the pilling rating raised from grade 2-3 to grade 4,and the whiteness value only decreased by 3.87%.
基金supported by a grant from the National Natural Science Foundation of China(81371577)
文摘BACKGROUNI）： Hepatocellular adenoma （HCA） is a rare benign tumor of the liver. It is of clinical importance to dif- ferentiate HCA from other liver tumors, especially hepatocel- lular carcinoma （HCC）. This study aimed to evaluate the char- acteristic features of HCA by conventional ultrasound and contrast-enhanced ultrasound （CEUS） findings. METHODS： Twenty-six patients （10 males and 16 females; mean age 36.2＋5.0 years） with 26 histopathologically proven HCAs were retrospectively identified. According to the maxi- mum diameter of HCAs, they were divided into three groups： 〈30 mm, 30-50 mm, and 〉50 mm. Ultrasound examinations were performed with C5-2 broadband curved transducer of Philips iU22 unit （Philips Bothell, WA, USA）. For each lesion, a dose of 2.4 mL SonoVue~ （Bracco Imaging Spa, Milan, Italy） was injected as a quick bolus into the cubital vein. Lesions＇ echogenicity, color-Doppler flow imaging and contrast en- hancement patterns were recorded. RESULTS： Grayscale ultrasound revealed that most of HCAs were hypoechoic （73.1%, 19/26）. Spotty calcifications were detected in 26.9% （7/26） of the lesions. Color-Doppler flow imaging detected centripetal bulky color flow in 46.2% （12/26） of the HCAs. CEUS showed that 73.1% （19/26） of the HCAs displayed as rapid, complete and homogenous enhancement, and 53.8% （14/26） showed decreased contrast enhancement in the late phase. There was no significant difference in enhance- ment patterns among different sizes of HCAs （P〉0.05）. Centripetal enhancement with subcapsular tortuous arteries was common in larger HCAs.
文摘Objective To assess recent trends and prognostic features in the treatment of pure mucinous carcinoma(PMC) of the breast.Methods Fifty-six patients diagnosed with PMC of the breast in our hospital from December 1982 to June 2008 were included.We evaluated the general information and tumor characteristics of the patients,examined the relationship between these factors and prognosis.Fisher's exact test was applied to analyze tumor characteristics.Results The mean age of the patients was 53.7 years.The majority of the patients presented with early stage disease.Tumor size was found not a significant prognostic factor in this study.Mean follow-up period was 39 months and no breast cancer-related deaths were identified in the patient cohort.Conclusions PMC of the breast has a favorable prognosis.Tumor size does not appear to significantly impact survival.
基金Projects(51375070,51574058) supported by the National Natural Science Foundation of China
文摘Three-layer6009/7050/6009aluminum alloy clad slab was fabricated by an innovative direct-chill casting process.To study the response of the clad slab to plastic deformation and heat treatments,homogenization annealing,hot rolling,solution and aging were successively performed on the as-cast6009/7050/6009clad samples.The results revealed that excellent metallurgical bonding between7050alloy layer and6009alloy layer was achieved under optimal parameters.The clad ratio obviously decreased when the annealed sample was rolled to55%hot reduction level,and then changed slightly with further rolling.Furthermore,the content of rodlike Zn-rich phases increased significantly in7050alloy layer in the homogenized clad samples after rolling at55%,65%and75%hot reduction levels,and the higher level of hot reduction resulted in narrower diffusion layer.Subsequent solution and aging significantly improved the hardness in7050alloy layer,interfaces and6009alloy layers of the rolled samples except for the thin side for the75%hot reduction sample.
基金supported in part by the National Natural Science Foundation of China,Key Project (10532010)the Ministry of Science and Technology of China’s Turbulence Program(2009CB724101)+1 种基金the National Basic Research Program of China(2007CB714600)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(10921202/A0204)
文摘By Green＇s function method we show that the water hammer （WH） can be analytically predicted for both laminar and turbulent flows （for the latter, with an eddy vis- cosity depending solely on the space coordinates）, and thus its hazardous effect can be rationally controlled and mini- mized. To this end, we generalize a laminar water hammer equation of Wang et al. （J. Hydrodynamics, B2, 51, 1995） to include arbitrary initial condition and variable viscosity, and obtain its solution by Green＇s function method. The pre- dicted characteristic WH behaviors by the solutions are in excellent agreement with both direct numerical simulation of the original governing equations and, by adjusting the eddy viscosity coefficient, experimentally measured turbulent flow data. Optimal WH control principle is thereby constructed and demonstrated.
基金supported by the National Natural Science Foundation of China(Grant Nos.12102365,91752202,11472016,11621202,and 12272371).
文摘This work attempts to extend the fundamental theory for classic gas dynamics to viscous compressible flow,of which aeroacoustics will naturally be a special branch.As a continuation of Part I.Unbounded fluid(Mao et al.,2022),this paper studies the source of longitudinal field at solid boundary,caused by the on-wall kinematic and viscous dynamic coupling of longitudinal and transverse processes.We find that at this situation the easiest choice for the two independent thermodynamic variables is the dimensionless pressure P and temperature T.The two-level structure of boundary dynamics of longitudinal field is obtained by applying the continuity equation and its normal derivative to the surface.We show that the boundary dilatation flux represents faithfully the boundary production of vortex sound and entropy sound,and the mutual generation mechanism of the longitudinal and transverse fields on the boundary does not occur symmetrically"at the samc level,but appears along a zigzag route.At the first level,it is the pressure gradient that generates vorticity unidirectionally;while at the second level,it is the vorticity that generates dilatation unidirectionally.
