The effects of the solid solution conditions on the microstructure and tensile properties of Al?Zn?Mg?Cu aluminum alloy were investigated by in-situ resistivity measurement, optical microscopy (OM), scanning electron ...The effects of the solid solution conditions on the microstructure and tensile properties of Al?Zn?Mg?Cu aluminum alloy were investigated by in-situ resistivity measurement, optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and tensile test. A radial basis function artificial neural network (RBF-ANN) model was developed for the analysis and prediction of the electrical resistivity of the tested alloy during the solid solution process. The results show that the model is capable of predicting the electrical resistivity with remarkable success. The correlation coefficient between the predicted results and experimental data is 0.9958 and the relative error is 0.33%. The predicted data were adopted to construct a novel physical picture which was defined as “solution resistivity map”. As revealed by the map, the optimum domain for the solid solution of the tested alloy is in the temperature range of 465?475 °C and solution time range of 50?60 min. In this domain, the solution of second particles and the recrystallization phenomenon will reach equilibrium.展开更多
The effects of pre-deformation following solution treatment on the microstructure and mechanical properties of aged high purity Al-Cu-Mg alloy were studied by tensile test, micro-hardness measurements, transmission el...The effects of pre-deformation following solution treatment on the microstructure and mechanical properties of aged high purity Al-Cu-Mg alloy were studied by tensile test, micro-hardness measurements, transmission electron microscopy and scanning electron microscopy. The micro-hardness measurements indicate that compared with un-deformed samples, the peak hardness is increased and the time to reach peak hardness is reduced with increasing pre-strain. Additionally, a double-peak hardness evolution behavior of cold-rolled （CR） samples was observed during aging. The results of TEM observation show that the number density of S′（Al2CuMg） phase is increased and the size is decreased in CR alloy with increase of pre-strain. The peak hardness and peak strength of the CR alloy are increased because of quantity increasing and refinement of S′ phase and high density dislocation.展开更多
Microsatellites or SSRs as powerful genetic markers have widely been used in genetics and evolutionary biology in common wheat. Because of the high polymorphism, newly synthesized hexaploid wheat has been used in the ...Microsatellites or SSRs as powerful genetic markers have widely been used in genetics and evolutionary biology in common wheat. Because of the high polymorphism, newly synthesized hexaploid wheat has been used in the construction of genetic segregation population for SSR markers, However, data on the evolution of microsatellites during the polyploidization event of hexaploid wheat are limited. In this study, 66 pairs of specific to A/B genome SSR patterns among newly synthesized hexaploid wheat, the donor tetraploid wheat and Aegilops tauschii were compared. The results indicated that most SSR markers were conserved during the polyploidization events of newly synthetic hexaploid wheat, from Triticum turgidum and Ae. tauschii. Over 70% A/B genome specific SSR markers could amplify the SSR sequences from the D genome ofAe. tauschii. Most amplified fragments from Ae, tauschii were detected in synthetic hexaploid at corresponding positions with the same sizes and patterns as in its parental Ae. tauschii. This suggested that these SSR markers, specific for A/B genome in common wheat, could amplify SSR products of D genome besides A/B genome in the newly synthesized hexaploid wheat, that is, these SSR primers specific for A/B genome in common wheat were nonspecific for the A/B genome in the synthetic hexaploid wheat. In addition, one amplified Ae. tauschii product was not detected in the newly synthetic hexaploid wheat. An extra-amplified product was found in the newly synthetic hexaploid wheat. These results suggested that caution should be taken when using SSR marker to genotype newly synthetic hexaploid wheat.展开更多
The feasibility of using an ANN method to predict the mercury emission and speciation in the flue gas of a power station under un-tested combustion/operational conditions is evaluated. Based on existing field testing ...The feasibility of using an ANN method to predict the mercury emission and speciation in the flue gas of a power station under un-tested combustion/operational conditions is evaluated. Based on existing field testing datasets for the emissions of three utility boilers, a 3-layer back-propagation network is applied to predict the mercury speciation at the stack. The whole prediction procedure includes： collection of data, structuring an artificial neural network （ANN） model, training process and error evaluation. A total of 59 parameters of coal and ash analyses and power plant operating conditions are treated as input variables, and the actual mercury emissions and their speciation data are used to supervise the training process and verify the performance of prediction modeling. The precision of model prediction （ root- mean-square error is 0. 8 μg/Nm3 for elemental mercury and 0. 9 μg/Nm3 for total mercury） is acceptable since the spikes of semi- mercury continuous emission monitor （SCEM） with wet conversion modules are taken into consideration.展开更多
In order to achieve good mechanical properties of Al-Cu alloys such as high strength and good toughness,precipitation hardening and artificial aging treatment were applied.As defined by the T6 heat treatment,the stand...In order to achieve good mechanical properties of Al-Cu alloys such as high strength and good toughness,precipitation hardening and artificial aging treatment were applied.As defined by the T6 heat treatment,the standard artificial aging treatment for Al-Cu alloy followed heat treatments of solution treatment at 510-530 ℃ for 2 h,quenching in water at 60 ℃ and then artificial aging at 160-190 ℃ for 2-8 h.The effects of solution treatment and artificial aging on the microstructure and mechanical properties of Al-Cu alloy were studied by optical microscopy（OM）,scanning electron microscopy（SEM）,energy dispersive X-ray spectroscopy（EDS）,transmission electron microscopy（TEM） and tensile test.The results of solution treatment indicate that the mechanical properties of Al-Cu alloy increase and then decrease with the increase of solution temperature.This is because the residual phases dissolve gradually into the matrix,and the fraction of the precipitation and the size of the re-crystallized grain increased.Compared to the solution temperature,the solution holding time has less effect on the microstructure and the mechanical properties of Al-Cu alloy.The artificial aging treatments were conducted at 160-180 ℃ for 2-8 h.The results show that the ultimate tensile strength can be obtained at 180 ℃ for 8 h.Ultimate tensile strength increased with increasing time or temperature.Yield strength was found as the same as the ultimate tensile strength result.展开更多
[Objective] This study aimed to investigate the histopathological changes in chickens artificially infected with infectious laryngotracheitis（ILT）. [Method] Through ar- tificial injection of allantoic liquid contain...[Objective] This study aimed to investigate the histopathological changes in chickens artificially infected with infectious laryngotracheitis（ILT）. [Method] Through ar- tificial injection of allantoic liquid containing ILTV into chickens to induce infectious laryngotracheitis, the clinical symptoms in infected chickens were observed; tissues of trachea, lungs, heart, liver, kidney and spleen were collected from dead chickens, and prepared into paraffin sections, followed by histopathological observation under a microscope. [Results] This disease occured in the inoculated chickens 3d later, with a morbidity rate of 95%. The main symptoms were dyspnea, asthma and coughing up of bloody exudate; yellowish-white pseudomembrane was observed on dissected larynx trachea; swelling, haemorrhage, and further erosion were observed on the in- fected tracheal mucosa, resulting in death of chickens, with the mortality rate of 25%; histopathological observation showed that parenchymal organs exhibited exuda- tive inflammation; swelling, degeneration, necrosis and shedding of epithelial cells were observed; disturbance of blood circulation occured.[Conclusion] This study pro- vides reference bases for the treatment of ILT.展开更多
We have constructed a full BAC library for the superior eaxly indica variety of OryZa sativa, Guang Lu Ai4. The MAX Efficiency DHlOB with increased stabilltyof inserts was used as BAC host cells. The potent pBelo BACI...We have constructed a full BAC library for the superior eaxly indica variety of OryZa sativa, Guang Lu Ai4. The MAX Efficiency DHlOB with increased stabilltyof inserts was used as BAC host cells. The potent pBelo BACII with double selection markers was used as cloning vector. The cloning efficiency we have reached was as high as 98%, and the transformation efficiency was raised up to 1Oo transformants / pg of large fragment DNA. The BAC recombinant transformants were picked at random and analyzed for the size of inserts, which turned out to be of 120 kb in length on average. We have obtained more than 20,000 such BAC clones. According to conventional probabillty equation, they covered the entire rice genome of 420,000 kb in length. The entire length of inserts of the library obtained has the 5- to 6- fold coverage of the genome. To our knowledge, this is the first reported full BAC library for a complex genome.展开更多
Objective To study if using autologous lung as a substitute of oxygenator in cardiopulmonary bypass is better than the conventional cardiopulmonary bypass with artificial oxygenator in pulmonary preservation. Methods ...Objective To study if using autologous lung as a substitute of oxygenator in cardiopulmonary bypass is better than the conventional cardiopulmonary bypass with artificial oxygenator in pulmonary preservation. Methods Twelve piglets were randomly divided into two groups （ n = 6）. The isolated lung perfusion model was established. The experimental animals underwent continuous lung perfusion for about 120 rain. While the control animals underwent 90 rain lung ischemia followed by 30 rain reperfusion. Another 12 piglets were randomly divided into two groups （ n =6）. The experimental animals underwent bi-ventricular bypass with autologous lung perfusion. While control animals underwent conventional cardiopulmonary bypass with artificial oxygenator. The bypass time and aortic cross clamping time were 135 rain and 60 rain respectively for each animal. The lung static compliance （Cstat）, alveolus-artery oxygen difference （PA-aO2 ） , TNF-α, IL-6 and wet to dry lung weight ratio （W/D） were measured. Histological and ultra-structural changes of the lung were also observed after bypass. Results After either isolated lung perfusion or cardiopulmonary bypass, the Cstat decreased, the PA-aO2 increased and the content of TNF-α increased for both groups, but the changes of experimental group were much less than those of control group. The lower W/D ratio and mild pathological changes in experimental group than those in control group were also demonstrated. Conclusion Autologous lung is able to tolerate the nonpulsatile perfusion. It can be used as a substitute to artificial ogygenator in cardiopulmonary bypass to minimize the inflammatory pulmonary injury caused mainly by ischemic reperfusion and interaction of the blood to the non-physiological surface of artificial oxygenator.展开更多
基金Project(51344004)supported by the National Natural Science Foundation of China
文摘The effects of the solid solution conditions on the microstructure and tensile properties of Al?Zn?Mg?Cu aluminum alloy were investigated by in-situ resistivity measurement, optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and tensile test. A radial basis function artificial neural network (RBF-ANN) model was developed for the analysis and prediction of the electrical resistivity of the tested alloy during the solid solution process. The results show that the model is capable of predicting the electrical resistivity with remarkable success. The correlation coefficient between the predicted results and experimental data is 0.9958 and the relative error is 0.33%. The predicted data were adopted to construct a novel physical picture which was defined as “solution resistivity map”. As revealed by the map, the optimum domain for the solid solution of the tested alloy is in the temperature range of 465?475 °C and solution time range of 50?60 min. In this domain, the solution of second particles and the recrystallization phenomenon will reach equilibrium.
基金Project(51301209)supported by the National Natural Science Foundation of China
文摘The effects of pre-deformation following solution treatment on the microstructure and mechanical properties of aged high purity Al-Cu-Mg alloy were studied by tensile test, micro-hardness measurements, transmission electron microscopy and scanning electron microscopy. The micro-hardness measurements indicate that compared with un-deformed samples, the peak hardness is increased and the time to reach peak hardness is reduced with increasing pre-strain. Additionally, a double-peak hardness evolution behavior of cold-rolled （CR） samples was observed during aging. The results of TEM observation show that the number density of S′（Al2CuMg） phase is increased and the size is decreased in CR alloy with increase of pre-strain. The peak hardness and peak strength of the CR alloy are increased because of quantity increasing and refinement of S′ phase and high density dislocation.
基金the project of Scientific Research Foundation for the Returned Overseas Chinese Scholars, New Century Excellent Talents in University (No. NCET-04-0908)Changjiang Scholars and Innovative Research Team in University (No. IRT0 453) of the Chinese Ministry of EducationNational Natural Science Foundation of China (No. 30270804), Education Department and Science and Technology Department of Sichuan Province.
文摘Microsatellites or SSRs as powerful genetic markers have widely been used in genetics and evolutionary biology in common wheat. Because of the high polymorphism, newly synthesized hexaploid wheat has been used in the construction of genetic segregation population for SSR markers, However, data on the evolution of microsatellites during the polyploidization event of hexaploid wheat are limited. In this study, 66 pairs of specific to A/B genome SSR patterns among newly synthesized hexaploid wheat, the donor tetraploid wheat and Aegilops tauschii were compared. The results indicated that most SSR markers were conserved during the polyploidization events of newly synthetic hexaploid wheat, from Triticum turgidum and Ae. tauschii. Over 70% A/B genome specific SSR markers could amplify the SSR sequences from the D genome ofAe. tauschii. Most amplified fragments from Ae, tauschii were detected in synthetic hexaploid at corresponding positions with the same sizes and patterns as in its parental Ae. tauschii. This suggested that these SSR markers, specific for A/B genome in common wheat, could amplify SSR products of D genome besides A/B genome in the newly synthesized hexaploid wheat, that is, these SSR primers specific for A/B genome in common wheat were nonspecific for the A/B genome in the synthetic hexaploid wheat. In addition, one amplified Ae. tauschii product was not detected in the newly synthetic hexaploid wheat. An extra-amplified product was found in the newly synthetic hexaploid wheat. These results suggested that caution should be taken when using SSR marker to genotype newly synthetic hexaploid wheat.
基金The National Basic Research Program of China (973Program) (No.2006CB200302)the Natural Science Foundation of JiangsuProvince (No.BK2007224).
文摘The feasibility of using an ANN method to predict the mercury emission and speciation in the flue gas of a power station under un-tested combustion/operational conditions is evaluated. Based on existing field testing datasets for the emissions of three utility boilers, a 3-layer back-propagation network is applied to predict the mercury speciation at the stack. The whole prediction procedure includes： collection of data, structuring an artificial neural network （ANN） model, training process and error evaluation. A total of 59 parameters of coal and ash analyses and power plant operating conditions are treated as input variables, and the actual mercury emissions and their speciation data are used to supervise the training process and verify the performance of prediction modeling. The precision of model prediction （ root- mean-square error is 0. 8 μg/Nm3 for elemental mercury and 0. 9 μg/Nm3 for total mercury） is acceptable since the spikes of semi- mercury continuous emission monitor （SCEM） with wet conversion modules are taken into consideration.
文摘In order to achieve good mechanical properties of Al-Cu alloys such as high strength and good toughness,precipitation hardening and artificial aging treatment were applied.As defined by the T6 heat treatment,the standard artificial aging treatment for Al-Cu alloy followed heat treatments of solution treatment at 510-530 ℃ for 2 h,quenching in water at 60 ℃ and then artificial aging at 160-190 ℃ for 2-8 h.The effects of solution treatment and artificial aging on the microstructure and mechanical properties of Al-Cu alloy were studied by optical microscopy（OM）,scanning electron microscopy（SEM）,energy dispersive X-ray spectroscopy（EDS）,transmission electron microscopy（TEM） and tensile test.The results of solution treatment indicate that the mechanical properties of Al-Cu alloy increase and then decrease with the increase of solution temperature.This is because the residual phases dissolve gradually into the matrix,and the fraction of the precipitation and the size of the re-crystallized grain increased.Compared to the solution temperature,the solution holding time has less effect on the microstructure and the mechanical properties of Al-Cu alloy.The artificial aging treatments were conducted at 160-180 ℃ for 2-8 h.The results show that the ultimate tensile strength can be obtained at 180 ℃ for 8 h.Ultimate tensile strength increased with increasing time or temperature.Yield strength was found as the same as the ultimate tensile strength result.
基金Supported by the Special Project of Department of Science and Technology of Hebei Province(08820412D)the Special Project of Qinhuangdao Municipal Bureau of Science and Technology[Qinkeji(2003)30-35]+1 种基金the Special Project of Shijiazhuang Municipal Bureau of Science and Technology(07150193A)the Scientific Research Innovation Team Project of Hebei Normal University of Science and Technology(TD201201)~~
文摘[Objective] This study aimed to investigate the histopathological changes in chickens artificially infected with infectious laryngotracheitis（ILT）. [Method] Through ar- tificial injection of allantoic liquid containing ILTV into chickens to induce infectious laryngotracheitis, the clinical symptoms in infected chickens were observed; tissues of trachea, lungs, heart, liver, kidney and spleen were collected from dead chickens, and prepared into paraffin sections, followed by histopathological observation under a microscope. [Results] This disease occured in the inoculated chickens 3d later, with a morbidity rate of 95%. The main symptoms were dyspnea, asthma and coughing up of bloody exudate; yellowish-white pseudomembrane was observed on dissected larynx trachea; swelling, haemorrhage, and further erosion were observed on the in- fected tracheal mucosa, resulting in death of chickens, with the mortality rate of 25%; histopathological observation showed that parenchymal organs exhibited exuda- tive inflammation; swelling, degeneration, necrosis and shedding of epithelial cells were observed; disturbance of blood circulation occured.[Conclusion] This study pro- vides reference bases for the treatment of ILT.
文摘We have constructed a full BAC library for the superior eaxly indica variety of OryZa sativa, Guang Lu Ai4. The MAX Efficiency DHlOB with increased stabilltyof inserts was used as BAC host cells. The potent pBelo BACII with double selection markers was used as cloning vector. The cloning efficiency we have reached was as high as 98%, and the transformation efficiency was raised up to 1Oo transformants / pg of large fragment DNA. The BAC recombinant transformants were picked at random and analyzed for the size of inserts, which turned out to be of 120 kb in length on average. We have obtained more than 20,000 such BAC clones. According to conventional probabillty equation, they covered the entire rice genome of 420,000 kb in length. The entire length of inserts of the library obtained has the 5- to 6- fold coverage of the genome. To our knowledge, this is the first reported full BAC library for a complex genome.
基金Supported by grants from National Natural Science Foundation of China (30170929).
文摘Objective To study if using autologous lung as a substitute of oxygenator in cardiopulmonary bypass is better than the conventional cardiopulmonary bypass with artificial oxygenator in pulmonary preservation. Methods Twelve piglets were randomly divided into two groups （ n = 6）. The isolated lung perfusion model was established. The experimental animals underwent continuous lung perfusion for about 120 rain. While the control animals underwent 90 rain lung ischemia followed by 30 rain reperfusion. Another 12 piglets were randomly divided into two groups （ n =6）. The experimental animals underwent bi-ventricular bypass with autologous lung perfusion. While control animals underwent conventional cardiopulmonary bypass with artificial oxygenator. The bypass time and aortic cross clamping time were 135 rain and 60 rain respectively for each animal. The lung static compliance （Cstat）, alveolus-artery oxygen difference （PA-aO2 ） , TNF-α, IL-6 and wet to dry lung weight ratio （W/D） were measured. Histological and ultra-structural changes of the lung were also observed after bypass. Results After either isolated lung perfusion or cardiopulmonary bypass, the Cstat decreased, the PA-aO2 increased and the content of TNF-α increased for both groups, but the changes of experimental group were much less than those of control group. The lower W/D ratio and mild pathological changes in experimental group than those in control group were also demonstrated. Conclusion Autologous lung is able to tolerate the nonpulsatile perfusion. It can be used as a substitute to artificial ogygenator in cardiopulmonary bypass to minimize the inflammatory pulmonary injury caused mainly by ischemic reperfusion and interaction of the blood to the non-physiological surface of artificial oxygenator.
