In this work, the main reasons for the breakage of 500 kV transmission line are studied. Under low temperature condition, the coverage of the ice results in the disconnection between the aluminum tube and the steel an...In this work, the main reasons for the breakage of 500 kV transmission line are studied. Under low temperature condition, the coverage of the ice results in the disconnection between the aluminum tube and the steel anchor of strain clamp. Using macroscopic analysis, structure stress analysis, force analysis and mechanical property test, the fractured strain clamps are investigated. The crimping of the aluminum tube on the polished rod not on the grooves of the steel anchor leads to the damage of the strain clamps, which is defined as improper crimping. When improper crimping emerges, there will be only friction force between the aluminum tube and the steel anchor without shear force, and the tension of the conductor will be mainly supported by the steel strands which should be supported by both the aluminum tube and steel stands. Therefore, the breaking force of the strain clamp will greatly decrease. The failure analysis helps to promote the proper hydraulic crimping process and the safe operation of the transmission line.展开更多
In this paper, the stress-strain curve of material is fitted by polygonal line composed of three lines. According to the theory of proportional loading in elastoplasticity, we simplify the complete stress-strain relat...In this paper, the stress-strain curve of material is fitted by polygonal line composed of three lines. According to the theory of proportional loading in elastoplasticity, we simplify the complete stress-strain relations, which are given by the increment theory of elastoplasticity. Thus, the finite element equation with the solution of displacement is derived. The assemblage elastoplastic stiffness matrix can be obtained by adding something to the elastic matrix, hence it will shorten the computing time. The determination of every loading increment follows the von Mises yield criteria. The iterative method is used in computation. It omits the redecomposition of the assemblage stiffness matrix and it will step further to shorten the computing time. Illustrations are given to the high-order element application departure from proportional loading, the computation of unloading fitting to the curve and the problem of load estimation.展开更多
The study and establishment of leukemia strains and leukemia cell lines have made great achievement in China.It has been extended from mice to rat model and related to explore human leukemia cell line and heterotransp...The study and establishment of leukemia strains and leukemia cell lines have made great achievement in China.It has been extended from mice to rat model and related to explore human leukemia cell line and heterotransplantable tumor strains. The cellular types of leukemia strain have included Iymphocytic,tmyelocytic,ecythroleukmia and megakaryoblastic cell strain.展开更多
Objective： To investigate the expression of cyclooxygenase-2 （COX-2） mRNA in drug-sensitive cell and drugresistant clones of ovarian cancer cell lines. Methods： RT-PCR and immunocytochemistry were used to investig...Objective： To investigate the expression of cyclooxygenase-2 （COX-2） mRNA in drug-sensitive cell and drugresistant clones of ovarian cancer cell lines. Methods： RT-PCR and immunocytochemistry were used to investigate the expression of cyclooxygenase-2 in 3 clones drug-sensitive and 5 clones drug-resistant ovarian cancer cell. Results： Strong COX-2 mRNA expressions were detected in 3 clones of drug-sensitive cell and weak expressions were detected in 5 clones of drug-resistant cell. The protein expression of COX-2 in drug-sensitive cell was strongly positive reaction in immunocytochemistry stain and there was a weak positive reaction in 5 clones of drug-resistant cell. Conclusion： The expression of COX-2 mRNA in drug-sensitive cell strains is much higher than that in drugresistant strains of ovarian cancer cell lines, providing a basis of the chemoprevention for ovarian cancer.展开更多
A set of near-isogenic rice lines withmonogenic resistance to bacterial blight weredeveloped by IRRI.The Cultivar IR24 wasused as the recurred parent.They wereevaluated with 6 races of Xanthomonascampestris pv.oryzae(...A set of near-isogenic rice lines withmonogenic resistance to bacterial blight weredeveloped by IRRI.The Cultivar IR24 wasused as the recurred parent.They wereevaluated with 6 races of Xanthomonascampestris pv.oryzae(Xco)in the Philip-pines at the maximum tillering and the bootingstages by ZHANG and MEW at IRRI in 1989.展开更多
Reproduction performance of 21 inbred experimental lines of White Leghorns was evaluated based on samples of reproduction records over a period of eight consecutive years. Two lines (63 and 72) have been extensively u...Reproduction performance of 21 inbred experimental lines of White Leghorns was evaluated based on samples of reproduction records over a period of eight consecutive years. Two lines (63 and 72) have been extensively used in studies, especially in research seeking for genetic and epigenetic factors underlying resistance to avian tumor virus-induced diseases in chickens. The other 19 lines are recombinant congenic strains (RCS), which were generated by crossing lines 63 and 72 followed by two consecutive backcrosses to the line 63 and then full-sib mating. In theory, each RCS processes 7/8 of progenitor background line 63 genome and a random sample (1/8) of the progenitor donor line 72 genome. All 21 inbred lines share a common major histocompatibility complex haplotype, B*2. The estimated average fertility of the 21 inbred lines ranged from 72.9% (RCS-J) up to 96.8% (RCS-P). Both progenitor lines 63 and 72 were observed with lower average fertility (82.4% and 81.6%, respectively) in comparison with the RCS except the RCS-J, suggesting a substantial polygenic component underlying the fertility phenotype. The average embryo mortality rate ranged from 14.5% (RCS-P) up to 47.0% (RCS-M). The background line 63 fell at about the middle of the range (28.3%) significantly higher than the donor line 72 (15.7%), which was among the group with the lowest embryo mortality. By definition, hatchability of fertile eggs is reversely correlated with embryo mortality. The average hatchability ranged from 26.5% (RCS-M) up to 66.8% (line 72) while the background line 63 remained (46.6%) at about the middle of the range. The variability of the average embryo mortality and hatchability observed among the 21 inbred lines indicated the two correlated traits also follow polygenic models of inheritance. Findings from this study paves the way for further investigation on genetic and environmental influence over reproductive performance of inbred lines of chickens, and particularly in understanding and improving the reproduction fitness of invaluable genetic resources like these inbred lines.展开更多
A new hydroforming process for manufacturing corrosion-resistant-alloy(CRA)-lined pipe is proposed to overcome the disadvantages in existing technologies, and a new kindof hydraulic expansion device for bimetallic CRA...A new hydroforming process for manufacturing corrosion-resistant-alloy(CRA)-lined pipe is proposed to overcome the disadvantages in existing technologies, and a new kindof hydraulic expansion device for bimetallic CRA-lined pipe has been researched and developed. Itsoperational principal and technical characteristic is also introduced. The stress and strain in theliner and outer pipe during the hydroforming process have been analyzed and the mechanism ofhydraulic expansion method is studied theoretically. The final forming pressure formula is suggestedand the theoretical analysis is verified by experimental investigation. The results indicate thatthe new technology is feasible and can be applied in industrial production.展开更多
According to the deformation state in skin stretch forming, an experiment was investigated to determine the critical strain, which make the slip line occur, and the strain criteria under different strain paths are obt...According to the deformation state in skin stretch forming, an experiment was investigated to determine the critical strain, which make the slip line occur, and the strain criteria under different strain paths are obtained. The uniaxial tension tests of different specimens were carried out to determine the critical strains of different strain paths. Then, the slip line limited curve(SLC) is available from these critical strains. Two kinds of aluminum alloys, 2024-T3 and 2524-T3, were studied, and two SLCs are gained. The application of the SLC to an airplane skin stretch forming simulation was investigated, and the results show that the SLC can be used to control the slip lines occurring in practice.展开更多
Wide-open V-shaped conjugate strike-slip faults in Asia are typically related to extrusion tectonics. However, the tectonic model based on the slip-line theory of plasticity has some critical problems associated with ...Wide-open V-shaped conjugate strike-slip faults in Asia are typically related to extrusion tectonics. However, the tectonic model based on the slip-line theory of plasticity has some critical problems associated with it. The conjugate sets of slip-lines in plane deformation, according to the theory of plasticity should be normal to each another but, in reality, the angles between the conjugate strike-slip faults, which are regarded as slip-lines in extrusion tectonics in the eastern Mediterranean, Tibet-middle Asia, China and the Indochina Peninsular regions, are always more than 90° （on average -110°） in the direction of contraction. Another problem is that the slip-line theory fails to explain how, in some cases, e.g., in the Anatolian area in the eastern Mediterranean, the extrusion rate is much higher than the indent rate. The two major problems are easy to solve in terms of the Maximum-Effective-Moment （MEM） Criterion that predicts that orientations of the shear zones are theoretically at an angle of 54.7° and practically at angles of 55°± 10° with the σ1- or contractional direction. The orientations of the strike-slip faults that accommodate extrusion tectonics are, therefore, fundamentally controlled by the MEM Criterion. When extrusion is along the MEM-orientations, the extruding rate is normally higher than the indenting rate.展开更多
文摘In this work, the main reasons for the breakage of 500 kV transmission line are studied. Under low temperature condition, the coverage of the ice results in the disconnection between the aluminum tube and the steel anchor of strain clamp. Using macroscopic analysis, structure stress analysis, force analysis and mechanical property test, the fractured strain clamps are investigated. The crimping of the aluminum tube on the polished rod not on the grooves of the steel anchor leads to the damage of the strain clamps, which is defined as improper crimping. When improper crimping emerges, there will be only friction force between the aluminum tube and the steel anchor without shear force, and the tension of the conductor will be mainly supported by the steel strands which should be supported by both the aluminum tube and steel stands. Therefore, the breaking force of the strain clamp will greatly decrease. The failure analysis helps to promote the proper hydraulic crimping process and the safe operation of the transmission line.
文摘In this paper, the stress-strain curve of material is fitted by polygonal line composed of three lines. According to the theory of proportional loading in elastoplasticity, we simplify the complete stress-strain relations, which are given by the increment theory of elastoplasticity. Thus, the finite element equation with the solution of displacement is derived. The assemblage elastoplastic stiffness matrix can be obtained by adding something to the elastic matrix, hence it will shorten the computing time. The determination of every loading increment follows the von Mises yield criteria. The iterative method is used in computation. It omits the redecomposition of the assemblage stiffness matrix and it will step further to shorten the computing time. Illustrations are given to the high-order element application departure from proportional loading, the computation of unloading fitting to the curve and the problem of load estimation.
文摘The study and establishment of leukemia strains and leukemia cell lines have made great achievement in China.It has been extended from mice to rat model and related to explore human leukemia cell line and heterotransplantable tumor strains. The cellular types of leukemia strain have included Iymphocytic,tmyelocytic,ecythroleukmia and megakaryoblastic cell strain.
基金National Natural Science Foundation of China (No.30070786)
文摘Objective： To investigate the expression of cyclooxygenase-2 （COX-2） mRNA in drug-sensitive cell and drugresistant clones of ovarian cancer cell lines. Methods： RT-PCR and immunocytochemistry were used to investigate the expression of cyclooxygenase-2 in 3 clones drug-sensitive and 5 clones drug-resistant ovarian cancer cell. Results： Strong COX-2 mRNA expressions were detected in 3 clones of drug-sensitive cell and weak expressions were detected in 5 clones of drug-resistant cell. The protein expression of COX-2 in drug-sensitive cell was strongly positive reaction in immunocytochemistry stain and there was a weak positive reaction in 5 clones of drug-resistant cell. Conclusion： The expression of COX-2 mRNA in drug-sensitive cell strains is much higher than that in drugresistant strains of ovarian cancer cell lines, providing a basis of the chemoprevention for ovarian cancer.
文摘A set of near-isogenic rice lines withmonogenic resistance to bacterial blight weredeveloped by IRRI.The Cultivar IR24 wasused as the recurred parent.They wereevaluated with 6 races of Xanthomonascampestris pv.oryzae(Xco)in the Philip-pines at the maximum tillering and the bootingstages by ZHANG and MEW at IRRI in 1989.
文摘Reproduction performance of 21 inbred experimental lines of White Leghorns was evaluated based on samples of reproduction records over a period of eight consecutive years. Two lines (63 and 72) have been extensively used in studies, especially in research seeking for genetic and epigenetic factors underlying resistance to avian tumor virus-induced diseases in chickens. The other 19 lines are recombinant congenic strains (RCS), which were generated by crossing lines 63 and 72 followed by two consecutive backcrosses to the line 63 and then full-sib mating. In theory, each RCS processes 7/8 of progenitor background line 63 genome and a random sample (1/8) of the progenitor donor line 72 genome. All 21 inbred lines share a common major histocompatibility complex haplotype, B*2. The estimated average fertility of the 21 inbred lines ranged from 72.9% (RCS-J) up to 96.8% (RCS-P). Both progenitor lines 63 and 72 were observed with lower average fertility (82.4% and 81.6%, respectively) in comparison with the RCS except the RCS-J, suggesting a substantial polygenic component underlying the fertility phenotype. The average embryo mortality rate ranged from 14.5% (RCS-P) up to 47.0% (RCS-M). The background line 63 fell at about the middle of the range (28.3%) significantly higher than the donor line 72 (15.7%), which was among the group with the lowest embryo mortality. By definition, hatchability of fertile eggs is reversely correlated with embryo mortality. The average hatchability ranged from 26.5% (RCS-M) up to 66.8% (line 72) while the background line 63 remained (46.6%) at about the middle of the range. The variability of the average embryo mortality and hatchability observed among the 21 inbred lines indicated the two correlated traits also follow polygenic models of inheritance. Findings from this study paves the way for further investigation on genetic and environmental influence over reproductive performance of inbred lines of chickens, and particularly in understanding and improving the reproduction fitness of invaluable genetic resources like these inbred lines.
基金This project is supported by National Science and Technology Foundation of China (No.96-918-02-03).
文摘A new hydroforming process for manufacturing corrosion-resistant-alloy(CRA)-lined pipe is proposed to overcome the disadvantages in existing technologies, and a new kindof hydraulic expansion device for bimetallic CRA-lined pipe has been researched and developed. Itsoperational principal and technical characteristic is also introduced. The stress and strain in theliner and outer pipe during the hydroforming process have been analyzed and the mechanism ofhydraulic expansion method is studied theoretically. The final forming pressure formula is suggestedand the theoretical analysis is verified by experimental investigation. The results indicate thatthe new technology is feasible and can be applied in industrial production.
基金Project(K0604020509) supported by Chengdu Aircraft Industrial Co. Ltd and National Foundation of Research of China
文摘According to the deformation state in skin stretch forming, an experiment was investigated to determine the critical strain, which make the slip line occur, and the strain criteria under different strain paths are obtained. The uniaxial tension tests of different specimens were carried out to determine the critical strains of different strain paths. Then, the slip line limited curve(SLC) is available from these critical strains. Two kinds of aluminum alloys, 2024-T3 and 2524-T3, were studied, and two SLCs are gained. The application of the SLC to an airplane skin stretch forming simulation was investigated, and the results show that the SLC can be used to control the slip lines occurring in practice.
基金supported by the National Nature Sciences Foundation of China(NNSFC/Grant Nos.90714006 and 40872133)
文摘Wide-open V-shaped conjugate strike-slip faults in Asia are typically related to extrusion tectonics. However, the tectonic model based on the slip-line theory of plasticity has some critical problems associated with it. The conjugate sets of slip-lines in plane deformation, according to the theory of plasticity should be normal to each another but, in reality, the angles between the conjugate strike-slip faults, which are regarded as slip-lines in extrusion tectonics in the eastern Mediterranean, Tibet-middle Asia, China and the Indochina Peninsular regions, are always more than 90° （on average -110°） in the direction of contraction. Another problem is that the slip-line theory fails to explain how, in some cases, e.g., in the Anatolian area in the eastern Mediterranean, the extrusion rate is much higher than the indent rate. The two major problems are easy to solve in terms of the Maximum-Effective-Moment （MEM） Criterion that predicts that orientations of the shear zones are theoretically at an angle of 54.7° and practically at angles of 55°± 10° with the σ1- or contractional direction. The orientations of the strike-slip faults that accommodate extrusion tectonics are, therefore, fundamentally controlled by the MEM Criterion. When extrusion is along the MEM-orientations, the extruding rate is normally higher than the indenting rate.
