AIM: To explore the feasibility of non-invasive quantitative estimation of portal venous pressure by contrast-enhanced ultrasound(CEUS) in a canine model.METHODS: Liver fibrosis was established in adult canines(Beagle...AIM: To explore the feasibility of non-invasive quantitative estimation of portal venous pressure by contrast-enhanced ultrasound(CEUS) in a canine model.METHODS: Liver fibrosis was established in adult canines(Beagles; n = 14) by subcutaneous injection of carbon tetrachloride(CCl4). CEUS parameters, including the area under the time-intensity curve and intensity at portal/arterial phases(Qp/Qa and Ip/Ia, respectively), were used to quantitatively assess the blood flow ratio of the portal vein/hepatic artery at multiple time points. The free portal venous pressures(FPP) were measured by a multi-channel baroreceptor using a percutaneous approach at baseline and 8, 16, and 24 wk after CCl4 injections in each canine. Liver biopsies were obtained at the end of 8, 16, and 24 wk from each animal, and the stage of the fibrosis was assessed according to the Metavir scoring system. A Pearson correlation test was performed to compare the FPP with Q p/Q a and I p/I a.RESULTS: Pathologic examination of 42 biopsies from the 14 canines at weeks 8, 16, and 24 revealed that liver fibrosis was induced by CCl4 and represented various stages of liver fibrosis, including F0(n = 3), F1(n = 12), F2(n = 14), F3(n = 11), and F4(n = 2). There were significant differences in the measurements of Qp/Qa(19.85 ± 3.30 vs 10.43 ± 1.21, 9.63 ± 1.03, and 8.77 ± 0.96) and Ip/Ia(1.77 ± 0.37 vs 1.03 ± 0.12, 0.83 ± 0.10, and 0.69 ± 0.13) between control and canine fibrosis at 8, 16, and 24 wk, respectively(all P < 0.001). There were statistically significant negative correlations between FPP and Q p/Q a(r =-0.707, P < 0.001), and between FPP and Ip/Ia(r =-0.759, P < 0.001) in the canine fibrosis model. Prediction of elevated FPP based on Q p/Q a and I p/I a was highly sensitive, as assessed by the area under the receiveroperating curve(0.866 and 0.895, respectively).CONCLUSION: C E U S i s a p o t e n t i a l m e t h o d t o accurately, but non-invasively, estimate portal venous pressure through measurement of Qp/Qa and Ip/Ia parameters.展开更多
Shrinkage porosity exists more or less in heavy castings, and it plays an important role in the fatigue behavior of cast materials. In this study, fatigue tests were carried out on the QT400-18 cast iron specimens con...Shrinkage porosity exists more or less in heavy castings, and it plays an important role in the fatigue behavior of cast materials. In this study, fatigue tests were carried out on the QT400-18 cast iron specimens containing random degrees of shrinkage porosity defect. Experimental results showed that the order of magnitude of life scattered from 103 to 106 cycles when the shrinkage percentage ranged from 0.67% to 5.91%. SEM analyses were carried out on the shrinkage porosity region. The inter-granular discontinuous, micro cracks and inclusions interfered with the fatigue sliding or hindering process. The slip in shrinkage porosity region was not as orderly as the ordinary continuous medium. The shrinkage porosity area on fracture surface(SPAFS) and alternating stress intensity factor(ASIF) were applied to evaluate the tendency of residual life distribution; their relationship was fitted by negative exponent functions. Based on the intermediate variable of ASIF, a fatigue life prediction model of nodular cast iron containing shrinkage porosity defects was established. The modeling prediction was in agreement with the experimental results.展开更多
By incorporating the strain gradient elasticity into the classical Bernoulli-Euler beam and Timoshenko beam models, the size-dependent characteristics of wave propaga- tion in micro/nanobeams is studied. The formulati...By incorporating the strain gradient elasticity into the classical Bernoulli-Euler beam and Timoshenko beam models, the size-dependent characteristics of wave propaga- tion in micro/nanobeams is studied. The formulations of dis- persion relation are explicitly derived for both strain gradi- ent beam models, and presented for different material length scale parameters （MLSPs）. For both phenomenological size- dependent beam models, the angular frequency, phase veloc- ity and group velocity increase with increasing wave num- ber. However, the velocity ratios approach different values for different beam models, indicating an interesting behavior of the asymptotic velocity ratio. The present theory is also compared with the nonlocal continuum beam models.展开更多
Bi-metal material consisting of spray-formed Al-22 Si and ZL104 is a suitable candidate for applications in internal combustion engines. This research investigated the effects of surface treatment and appropriate gati...Bi-metal material consisting of spray-formed Al-22 Si and ZL104 is a suitable candidate for applications in internal combustion engines. This research investigated the effects of surface treatment and appropriate gating system on the microstructures and mechanical properties in evaluating the optimal strategy for producing high quality bi-metal materials. The bi-metal materials were prepared using ZL104 gravity casting by different pouring types around the spray-formed Al-22 Si with varied surface treatments. The wettability between Al-22 Si and ZL104 was significantly improved when Zn coating was used to remove the natural oxide layer. This research also obtained the improved interfacial microstructures and interfacial bonding strength for materials when applying the appropriate pouring method. The hardness profiles of Al-22Si/ZL104 bi-metal were consistent with the observed microstructures. The average tensile strength of the bi-metal material with zinc coating is ~42.3 MPa, which is much higher than that with oxide film at ~10 MPa. The process presented is a promising and effective approach for developing materials in the automotive industry.展开更多
Hemangiopericytoma is clinically rare and easily confused with meningioma.Right-sided aortic arch is also a rare disease of congenital cardiovascular variability.The intracranial hemangiopericytoma associated with the...Hemangiopericytoma is clinically rare and easily confused with meningioma.Right-sided aortic arch is also a rare disease of congenital cardiovascular variability.The intracranial hemangiopericytoma associated with the right-sided aortic arch has not been reported in the literature.We are here to register a case of right aortic arch concurrent with intracranial hemangiopericytoma;the patient was initially thought to be a simple meningioma,but he was eventually diagnosed as a hemangiopericytoma with right aortic arch and multiple intracranial vascular stenosis and malformation.Whether there was a genetic correlation between the two provides a potential research direction for us.Therefore,the diagnosis and treatment of some rare diseases should be a more comprehensive analysis and evaluation.Adequate examination and accurate diagnosis are crucial,which will directly affect the efficacy of surgery and the prognosis of patients.展开更多
Software intelligent development has become one of the most important research trends in software engineering. In this paper, we put forward two key concepts -- intelligent development environment （IntelliDE） and so...Software intelligent development has become one of the most important research trends in software engineering. In this paper, we put forward two key concepts -- intelligent development environment （IntelliDE） and software knowledge graph -- for the first time. IntelliDE is an ecosystem in which software big data are aggregated, mined and analyzed to provide intelligent assistance in the life cycle of software development. We present its architecture and discuss its key research issues and challenges. Software knowledge graph is a software knowledge representation and management framework, which plays an important role in IntelliDE. We study its concept and introduce some concrete details and examples to show how it could be constructed and leveraged.展开更多
The solidification behavior and intermetallic phase evolution during homogenization annealing of an Al-Zn-Mg-Cu alloy with 0.12 wt%Ce addition were examined.The residual Al_(2)CuMg phase is completely dissolved after ...The solidification behavior and intermetallic phase evolution during homogenization annealing of an Al-Zn-Mg-Cu alloy with 0.12 wt%Ce addition were examined.The residual Al_(2)CuMg phase is completely dissolved after homogenization and is replaced by a large number of dispersed micro/nanoscaled AlCuCe enrichment phases within Al matrix.This change occurs because of the formation of a large number of finer lamellar eutectic network structures which are more easily dissolved into Al matrix during the homogenization process.In addition,the trapping of Cu atoms in the stable AlCuCe phase also prevents the formation of Al_(2)CuMg phase,leading to the complete dissolution of Al_(2)CuMg phase in the Al-Zn-MgCu alloy.The grain refinement behavior in Al alloy with Ce addition is similar to that in alloys with the addition of Sc,because of the formation of primary Ce-enriched Al_(11)Ce_(3)phase as the nucleation agent ofα(Al)during solidification.展开更多
The Al22Si/ZL102 bimetal was designed and prepared by extrusion at near-eutectic temperature.The properties and fracture behaviors of different surface treatments between oxide film and zinc coating were compared betw...The Al22Si/ZL102 bimetal was designed and prepared by extrusion at near-eutectic temperature.The properties and fracture behaviors of different surface treatments between oxide film and zinc coating were compared between the Al22 Si and ZL102 bimetal.The average bonding strength of bimetal with intermittent oxide film interface was about 89.3MPa,which is higher than that of the bimetal fabricated by zinc coating method（about 76.3MPa）.During the process of extrusion,the oxidation film was extruded to crush and the metal was extruded through the micro-cracks of the oxidation film,then the two surfaces were joined together.Altogether,the results showed that extrusion at near-eutectic temperature is favorable for achieving a high-quality metallurgical bonded interface.展开更多
Legacy system migration to the cloud brings both great challenges and benefits, so there exist various academic research and industrial applications on legacy system migration to the cloud. By analyzing the research a...Legacy system migration to the cloud brings both great challenges and benefits, so there exist various academic research and industrial applications on legacy system migration to the cloud. By analyzing the research achievements and application status,we divide the existing migration methods into three strategies according to the cloud service models integrally. Different processes need to be considered for different migration strategies, and different tasks will be involved accordingly. The similarities and differences between the migration strategies are discussed, and the challenges and future work about legacy system migration to the cloud are proposed. The aim of this paper is to provide an overall presentation for legacy system migration to the cloud and identify important challenges and future research directions.展开更多
文摘AIM: To explore the feasibility of non-invasive quantitative estimation of portal venous pressure by contrast-enhanced ultrasound(CEUS) in a canine model.METHODS: Liver fibrosis was established in adult canines(Beagles; n = 14) by subcutaneous injection of carbon tetrachloride(CCl4). CEUS parameters, including the area under the time-intensity curve and intensity at portal/arterial phases(Qp/Qa and Ip/Ia, respectively), were used to quantitatively assess the blood flow ratio of the portal vein/hepatic artery at multiple time points. The free portal venous pressures(FPP) were measured by a multi-channel baroreceptor using a percutaneous approach at baseline and 8, 16, and 24 wk after CCl4 injections in each canine. Liver biopsies were obtained at the end of 8, 16, and 24 wk from each animal, and the stage of the fibrosis was assessed according to the Metavir scoring system. A Pearson correlation test was performed to compare the FPP with Q p/Q a and I p/I a.RESULTS: Pathologic examination of 42 biopsies from the 14 canines at weeks 8, 16, and 24 revealed that liver fibrosis was induced by CCl4 and represented various stages of liver fibrosis, including F0(n = 3), F1(n = 12), F2(n = 14), F3(n = 11), and F4(n = 2). There were significant differences in the measurements of Qp/Qa(19.85 ± 3.30 vs 10.43 ± 1.21, 9.63 ± 1.03, and 8.77 ± 0.96) and Ip/Ia(1.77 ± 0.37 vs 1.03 ± 0.12, 0.83 ± 0.10, and 0.69 ± 0.13) between control and canine fibrosis at 8, 16, and 24 wk, respectively(all P < 0.001). There were statistically significant negative correlations between FPP and Q p/Q a(r =-0.707, P < 0.001), and between FPP and Ip/Ia(r =-0.759, P < 0.001) in the canine fibrosis model. Prediction of elevated FPP based on Q p/Q a and I p/I a was highly sensitive, as assessed by the area under the receiveroperating curve(0.866 and 0.895, respectively).CONCLUSION: C E U S i s a p o t e n t i a l m e t h o d t o accurately, but non-invasively, estimate portal venous pressure through measurement of Qp/Qa and Ip/Ia parameters.
基金supported by the National Natural Science Foundation of China(Grant No.51305350)the Natural Science Foundation of Shaanxi Province(No.2013JM6011)the Basic Researches Foundation of NWPU(No.3102014JCQ01045)
文摘Shrinkage porosity exists more or less in heavy castings, and it plays an important role in the fatigue behavior of cast materials. In this study, fatigue tests were carried out on the QT400-18 cast iron specimens containing random degrees of shrinkage porosity defect. Experimental results showed that the order of magnitude of life scattered from 103 to 106 cycles when the shrinkage percentage ranged from 0.67% to 5.91%. SEM analyses were carried out on the shrinkage porosity region. The inter-granular discontinuous, micro cracks and inclusions interfered with the fatigue sliding or hindering process. The slip in shrinkage porosity region was not as orderly as the ordinary continuous medium. The shrinkage porosity area on fracture surface(SPAFS) and alternating stress intensity factor(ASIF) were applied to evaluate the tendency of residual life distribution; their relationship was fitted by negative exponent functions. Based on the intermediate variable of ASIF, a fatigue life prediction model of nodular cast iron containing shrinkage porosity defects was established. The modeling prediction was in agreement with the experimental results.
基金supported by the National Natural Science Foundation of China(11202117,11272186,11172231 and 50928601)the Postdoctoral Science Foundation of China(2012M521326)+3 种基金the Natural Science Fund of Shandong Province(ZR2012AM014 and BS2012ZZ006)Independent Innovation Fund of Shandong University(2011GN055)National Science Foundation(CMMI-0643726),DARPA(W91CRB-11-C-0112)Changjiang Scholar Program from Ministry of Education of China
文摘By incorporating the strain gradient elasticity into the classical Bernoulli-Euler beam and Timoshenko beam models, the size-dependent characteristics of wave propaga- tion in micro/nanobeams is studied. The formulations of dis- persion relation are explicitly derived for both strain gradi- ent beam models, and presented for different material length scale parameters （MLSPs）. For both phenomenological size- dependent beam models, the angular frequency, phase veloc- ity and group velocity increase with increasing wave num- ber. However, the velocity ratios approach different values for different beam models, indicating an interesting behavior of the asymptotic velocity ratio. The present theory is also compared with the nonlocal continuum beam models.
基金financially supported by the National Natural Science Foundation of China(No.51375110)
文摘Bi-metal material consisting of spray-formed Al-22 Si and ZL104 is a suitable candidate for applications in internal combustion engines. This research investigated the effects of surface treatment and appropriate gating system on the microstructures and mechanical properties in evaluating the optimal strategy for producing high quality bi-metal materials. The bi-metal materials were prepared using ZL104 gravity casting by different pouring types around the spray-formed Al-22 Si with varied surface treatments. The wettability between Al-22 Si and ZL104 was significantly improved when Zn coating was used to remove the natural oxide layer. This research also obtained the improved interfacial microstructures and interfacial bonding strength for materials when applying the appropriate pouring method. The hardness profiles of Al-22Si/ZL104 bi-metal were consistent with the observed microstructures. The average tensile strength of the bi-metal material with zinc coating is ~42.3 MPa, which is much higher than that with oxide film at ~10 MPa. The process presented is a promising and effective approach for developing materials in the automotive industry.
文摘Hemangiopericytoma is clinically rare and easily confused with meningioma.Right-sided aortic arch is also a rare disease of congenital cardiovascular variability.The intracranial hemangiopericytoma associated with the right-sided aortic arch has not been reported in the literature.We are here to register a case of right aortic arch concurrent with intracranial hemangiopericytoma;the patient was initially thought to be a simple meningioma,but he was eventually diagnosed as a hemangiopericytoma with right aortic arch and multiple intracranial vascular stenosis and malformation.Whether there was a genetic correlation between the two provides a potential research direction for us.Therefore,the diagnosis and treatment of some rare diseases should be a more comprehensive analysis and evaluation.Adequate examination and accurate diagnosis are crucial,which will directly affect the efficacy of surgery and the prognosis of patients.
文摘Software intelligent development has become one of the most important research trends in software engineering. In this paper, we put forward two key concepts -- intelligent development environment （IntelliDE） and software knowledge graph -- for the first time. IntelliDE is an ecosystem in which software big data are aggregated, mined and analyzed to provide intelligent assistance in the life cycle of software development. We present its architecture and discuss its key research issues and challenges. Software knowledge graph is a software knowledge representation and management framework, which plays an important role in IntelliDE. We study its concept and introduce some concrete details and examples to show how it could be constructed and leveraged.
基金the Natural Science Foundation of Shandong Province,China(Nos.ZR2017PEM005 and ZR2017MEM005)the Project of Scientific Research Development of Shandong Universities China(Nos.J17KA043 and J17KB076)+2 种基金the Key Research Program of Shandong Province,China(No.2015GGX102021)the Foundation for Applied Science and Technology Research and Development Program of Guangdong Province,China(No.2015B090926007)2015 Shandong Province Project of Outstanding Subject Talent Group。
文摘The solidification behavior and intermetallic phase evolution during homogenization annealing of an Al-Zn-Mg-Cu alloy with 0.12 wt%Ce addition were examined.The residual Al_(2)CuMg phase is completely dissolved after homogenization and is replaced by a large number of dispersed micro/nanoscaled AlCuCe enrichment phases within Al matrix.This change occurs because of the formation of a large number of finer lamellar eutectic network structures which are more easily dissolved into Al matrix during the homogenization process.In addition,the trapping of Cu atoms in the stable AlCuCe phase also prevents the formation of Al_(2)CuMg phase,leading to the complete dissolution of Al_(2)CuMg phase in the Al-Zn-MgCu alloy.The grain refinement behavior in Al alloy with Ce addition is similar to that in alloys with the addition of Sc,because of the formation of primary Ce-enriched Al_(11)Ce_(3)phase as the nucleation agent ofα(Al)during solidification.
文摘The Al22Si/ZL102 bimetal was designed and prepared by extrusion at near-eutectic temperature.The properties and fracture behaviors of different surface treatments between oxide film and zinc coating were compared between the Al22 Si and ZL102 bimetal.The average bonding strength of bimetal with intermittent oxide film interface was about 89.3MPa,which is higher than that of the bimetal fabricated by zinc coating method（about 76.3MPa）.During the process of extrusion,the oxidation film was extruded to crush and the metal was extruded through the micro-cracks of the oxidation film,then the two surfaces were joined together.Altogether,the results showed that extrusion at near-eutectic temperature is favorable for achieving a high-quality metallurgical bonded interface.
基金supported by National Natural Science Foundationof China(No.61262082)Key Project of Chinese Ministry of Education(No.212025)+2 种基金Inner Mongolia Science Foundation for Distinguished Young Scholars(No.2012JQ03)Inner Mongolia Natural Science Foundation of Inner Mongolia(No.2011MS0911)Postgraduate Scientific Research Innovation Project of Inner Mongolia(No.1402020201013)
文摘Legacy system migration to the cloud brings both great challenges and benefits, so there exist various academic research and industrial applications on legacy system migration to the cloud. By analyzing the research achievements and application status,we divide the existing migration methods into three strategies according to the cloud service models integrally. Different processes need to be considered for different migration strategies, and different tasks will be involved accordingly. The similarities and differences between the migration strategies are discussed, and the challenges and future work about legacy system migration to the cloud are proposed. The aim of this paper is to provide an overall presentation for legacy system migration to the cloud and identify important challenges and future research directions.
