The effect of Ru on γ＇ precipitation behavior and evolution in single crystal superalloys with different Ru contents were investigated by scanning electron microscopy with energy dispersive spectroscopy,3D atomic pr...The effect of Ru on γ＇ precipitation behavior and evolution in single crystal superalloys with different Ru contents were investigated by scanning electron microscopy with energy dispersive spectroscopy,3D atomic probing,differential scanning calorimetry.The results show that the solvus of the γ＇ phase decreases gradually with increasing Ru content in the alloys by casting or by the same solution and aging treatments,the alloy with a larger Ru content yields a smaller γ＇ phase.The addition of Ru increases the growth rate and coarsening rate of the γ＇ phase.Ru mainly distributes in the γ phase,which causes more Re and Mo partition into the γ＇ phase,increasing the absolute value of mismatch and the rafting rate of the γ＇ phase.展开更多
In order to study the influence of microstructural texture on the growth of short fatigue cracks in metals, the nonequilibrium statistical theory of fatigue fracture correlating a microscopic mechanism with the macros...In order to study the influence of microstructural texture on the growth of short fatigue cracks in metals, the nonequilibrium statistical theory of fatigue fracture correlating a microscopic mechanism with the macroscopic properties is modified to take into consideration the microstructural features of a material, thereby allowing a rationalisation of the experimental data of short fatigue crack growth and long fatigue crack growth. The nonequilibrium statistical theory thus developed relates the growth of cracks with a dislocation mechanism to simulate short fatigue crack growth with the long fatigue crack growth behaviour and predicts the fatigue crack growth rates throughout the fatigue lifetime. The results is finally compared with that of other fatigue theories.展开更多
The dinoflagellate Dinophysis acurninata Claparede ＆ Lachrnann is a toxic alga that causes diarrhetic shellfish poisoning. No Dinophysis species were maintained in culture for a long period of time until 2006 when Pa...The dinoflagellate Dinophysis acurninata Claparede ＆ Lachrnann is a toxic alga that causes diarrhetic shellfish poisoning. No Dinophysis species were maintained in culture for a long period of time until 2006 when Park successfully established D. acuminata in culture using a three-step feeding protocol in which the cryptophyte, Geminigera cryophila, is fed to Myrionecta rubra （=Mesodinium rubrum）, a ciliate that is in turn fed to D. acuminata. In this paper, we present the details of culturing D. acuminata from the Northeastern United States. The protocols described herein can be adopted for laboratory studies of this species. The effects of temperature on the growth and ingestion rates of D. acuminata were also examined. The results show that D. acuminata growth rate was 0.23/d at 10℃ and 0.11/d at 4℃when fed M. rubra prey. The maximum prey ingestion rate was 2.80 Dinophysis cell/d at 10℃, although the rate decreased slightly at 4℃. In overall, temperature showed a greater influence on growth rate of D. acuminata than on the ingestion rate under the study conditions, and the quantity of available food was also an important regulator to D. acurninata growth.展开更多
Lingwu Changzao （Ziziphus. jujube Mill） is a Ningxia local variety, it has a good table quality despite its short postharvest life. The respiration rate, the weight change of single fruit during growth development a...Lingwu Changzao （Ziziphus. jujube Mill） is a Ningxia local variety, it has a good table quality despite its short postharvest life. The respiration rate, the weight change of single fruit during growth development and the losing water of postharvest of fruit were studied. The results showed that the curve of fruit growth development was a double sigmoid characteristic. When the surface colour of fruit changed form jade-green to alizarin crimson, the respiration rate tended to fall during a entire growth development of fruit, which showed a fluctuation phenomenon. The respiration rate descended when the surface color changed from coloring to baby red, but after a crimson stage the respiration rate recurred to its original downtrend. With increasing of single fruit weight, phenomenon of respiration climacteric has not happened and the respiration rate curve showed a concavity characteristic at some stages. As a result, there was not a phenomenon of respiration climacteric with a double sigmoid growth development curve characteristic of fruit.展开更多
The fast densification method of combustion reaction plus quick pressing was adopted to prepare nanocrystalline ceramics.The densification process of magnesia compact with a particle size of 100 nm was investigated,un...The fast densification method of combustion reaction plus quick pressing was adopted to prepare nanocrystalline ceramics.The densification process of magnesia compact with a particle size of 100 nm was investigated,under the applied pressure of up to 170 MPa,and the temperature range of 1740–2080 K with ultra-high heating rate(above 1700 K/min).High-purity magnesia ceramics with a relative density of 98.8%and an average grain size of 120 nm was obtained at 1740 K,and the grain growth during the densification process was effectively restrained.The characteristic morphology of evaporation-condensation was observed in the compact prepared at 2080 K,which revealed the actual process of mass transfer by gas diffusion.Moreover,the investigation on the microstructure evolution and mechanism of grain growth was carried out,on the basis of as-preserved nanocrystalline ceramics.The result indicated that the grain growth of the nanocrystalline MgO was controlled by the mechanism of evaporation-condensation rather than surface diffusion.Furthermore,the pressure had an influence of restraining the grain growth based on solid diffusion and strengthening the effect of gas diffusion with the increasing temperature.Under the particular conditions,there existed an appropriate temperature for the densification of nanocrystalline magnesia,while the excessive temperature would exaggerate grain growth and impede densification.展开更多
Objective: To study the drug property differences of Shexiang (Moschus) and Bingpian (Borneolum Synthcticum) with biothermodynamics, and to verify the objectivity and authenticity of the drug property. Methods: The gr...Objective: To study the drug property differences of Shexiang (Moschus) and Bingpian (Borneolum Synthcticum) with biothermodynamics, and to verify the objectivity and authenticity of the drug property. Methods: The growth-thermogram curves of Escherichia coli (E. coli) affected by Shexiang (Moschus) and Bingpian (Borneolum Synthcticum) at different concentrations were determined with microcalorimetry, and the power-time curves (thermogram curves) of E. coli metabolism and characteristic parameters, such as growth rate constant (k), maximum output power (Pm), peak time (tp), total heat-output (Qt), etc. were analyzed with the principal component analysis (PCA) to find the close correlative parameters, so as to objectively reflect the drug property differences of Shexiang (Moschus) and Bingpian (Borneolum Synthcticum). Results: The values of P2 in the second exponential growth phase increased with the increase of the concentrations of Shexiang (Moschus) and Bingpian (Borneolum Synthcticum), and the P2 of Shexiang (Moschus) was larger than that of Bingpian (Borneolum Synthcticum); Q2 increased with the increase of the concentrations of Shexiang (Moschus), but for Bingpian (Borneolum Synthcticum) it was opposite. It is indicated that they have different effects on P2 and Q2 of E. coli in the second exponential growth phase, and have differences in warm and cold natures. Conclusion: The microcalorimetry can accurately and objectively appraise differences of the drug property of Shexiang (Moschus) and Bingpian (Borneolum Synthcticum) and verify the objectivity and authenticity of the drug property, so as to provide a new and useful method for studies of the drug property of Chinese drugs.展开更多
基金Project(U1037601) supported by the National Natural Science Foundation of China
文摘The effect of Ru on γ＇ precipitation behavior and evolution in single crystal superalloys with different Ru contents were investigated by scanning electron microscopy with energy dispersive spectroscopy,3D atomic probing,differential scanning calorimetry.The results show that the solvus of the γ＇ phase decreases gradually with increasing Ru content in the alloys by casting or by the same solution and aging treatments,the alloy with a larger Ru content yields a smaller γ＇ phase.The addition of Ru increases the growth rate and coarsening rate of the γ＇ phase.Ru mainly distributes in the γ phase,which causes more Re and Mo partition into the γ＇ phase,increasing the absolute value of mismatch and the rafting rate of the γ＇ phase.
文摘In order to study the influence of microstructural texture on the growth of short fatigue cracks in metals, the nonequilibrium statistical theory of fatigue fracture correlating a microscopic mechanism with the macroscopic properties is modified to take into consideration the microstructural features of a material, thereby allowing a rationalisation of the experimental data of short fatigue crack growth and long fatigue crack growth. The nonequilibrium statistical theory thus developed relates the growth of cracks with a dislocation mechanism to simulate short fatigue crack growth with the long fatigue crack growth behaviour and predicts the fatigue crack growth rates throughout the fatigue lifetime. The results is finally compared with that of other fatigue theories.
基金provided by a grand fostering project from the Ministry of Education,People’s Republic of China (No 707011)the China Scholarship Council(CSC)2007+2 种基金supported by grants (to ANDERSON M Donald) from the US. National Science Foundation (Nos. NSF OCE-0402707OCE-0850421)the Ocean Life Institute at the Woods Hole Oceanographic Institution
文摘The dinoflagellate Dinophysis acurninata Claparede ＆ Lachrnann is a toxic alga that causes diarrhetic shellfish poisoning. No Dinophysis species were maintained in culture for a long period of time until 2006 when Park successfully established D. acuminata in culture using a three-step feeding protocol in which the cryptophyte, Geminigera cryophila, is fed to Myrionecta rubra （=Mesodinium rubrum）, a ciliate that is in turn fed to D. acuminata. In this paper, we present the details of culturing D. acuminata from the Northeastern United States. The protocols described herein can be adopted for laboratory studies of this species. The effects of temperature on the growth and ingestion rates of D. acuminata were also examined. The results show that D. acuminata growth rate was 0.23/d at 10℃ and 0.11/d at 4℃when fed M. rubra prey. The maximum prey ingestion rate was 2.80 Dinophysis cell/d at 10℃, although the rate decreased slightly at 4℃. In overall, temperature showed a greater influence on growth rate of D. acuminata than on the ingestion rate under the study conditions, and the quantity of available food was also an important regulator to D. acurninata growth.
文摘Lingwu Changzao （Ziziphus. jujube Mill） is a Ningxia local variety, it has a good table quality despite its short postharvest life. The respiration rate, the weight change of single fruit during growth development and the losing water of postharvest of fruit were studied. The results showed that the curve of fruit growth development was a double sigmoid characteristic. When the surface colour of fruit changed form jade-green to alizarin crimson, the respiration rate tended to fall during a entire growth development of fruit, which showed a fluctuation phenomenon. The respiration rate descended when the surface color changed from coloring to baby red, but after a crimson stage the respiration rate recurred to its original downtrend. With increasing of single fruit weight, phenomenon of respiration climacteric has not happened and the respiration rate curve showed a concavity characteristic at some stages. As a result, there was not a phenomenon of respiration climacteric with a double sigmoid growth development curve characteristic of fruit.
基金supported by the Ministry of Science and Technology of China(Grant No.S2010GR0771)the National Natural Science Foundation of China(Grant No.51161140399)
文摘The fast densification method of combustion reaction plus quick pressing was adopted to prepare nanocrystalline ceramics.The densification process of magnesia compact with a particle size of 100 nm was investigated,under the applied pressure of up to 170 MPa,and the temperature range of 1740–2080 K with ultra-high heating rate(above 1700 K/min).High-purity magnesia ceramics with a relative density of 98.8%and an average grain size of 120 nm was obtained at 1740 K,and the grain growth during the densification process was effectively restrained.The characteristic morphology of evaporation-condensation was observed in the compact prepared at 2080 K,which revealed the actual process of mass transfer by gas diffusion.Moreover,the investigation on the microstructure evolution and mechanism of grain growth was carried out,on the basis of as-preserved nanocrystalline ceramics.The result indicated that the grain growth of the nanocrystalline MgO was controlled by the mechanism of evaporation-condensation rather than surface diffusion.Furthermore,the pressure had an influence of restraining the grain growth based on solid diffusion and strengthening the effect of gas diffusion with the increasing temperature.Under the particular conditions,there existed an appropriate temperature for the densification of nanocrystalline magnesia,while the excessive temperature would exaggerate grain growth and impede densification.
基金supported by National Key Basic Research and Development Plant (973),China (No. 2007CB512 606)
文摘Objective: To study the drug property differences of Shexiang (Moschus) and Bingpian (Borneolum Synthcticum) with biothermodynamics, and to verify the objectivity and authenticity of the drug property. Methods: The growth-thermogram curves of Escherichia coli (E. coli) affected by Shexiang (Moschus) and Bingpian (Borneolum Synthcticum) at different concentrations were determined with microcalorimetry, and the power-time curves (thermogram curves) of E. coli metabolism and characteristic parameters, such as growth rate constant (k), maximum output power (Pm), peak time (tp), total heat-output (Qt), etc. were analyzed with the principal component analysis (PCA) to find the close correlative parameters, so as to objectively reflect the drug property differences of Shexiang (Moschus) and Bingpian (Borneolum Synthcticum). Results: The values of P2 in the second exponential growth phase increased with the increase of the concentrations of Shexiang (Moschus) and Bingpian (Borneolum Synthcticum), and the P2 of Shexiang (Moschus) was larger than that of Bingpian (Borneolum Synthcticum); Q2 increased with the increase of the concentrations of Shexiang (Moschus), but for Bingpian (Borneolum Synthcticum) it was opposite. It is indicated that they have different effects on P2 and Q2 of E. coli in the second exponential growth phase, and have differences in warm and cold natures. Conclusion: The microcalorimetry can accurately and objectively appraise differences of the drug property of Shexiang (Moschus) and Bingpian (Borneolum Synthcticum) and verify the objectivity and authenticity of the drug property, so as to provide a new and useful method for studies of the drug property of Chinese drugs.
