On the basis of a one-by-one latitude-longitude grid three-dimensional seismic velocity model, the crustal P-wave velocity structure in eastern China (105-125°E and 18-41°N) is obtained, and a set of geother...On the basis of a one-by-one latitude-longitude grid three-dimensional seismic velocity model, the crustal P-wave velocity structure in eastern China (105-125°E and 18-41°N) is obtained, and a set of geotherms for each grid is established for P-T correction on P-wave velocities. The average depths of sub-crustal layers and their average P-wave velocities of 18 tectonic units in eastern China are exhibited. Our result presents a 32-34 km thick crust beneath eastern China, which is thinner than previous studies, with an average velocity of 6.54 km/s, corresponding to a 5 kg/m3 variation in crustal mean density. The thicker upper but thinner middle and lower crust results in a lower average seismic velocity of eastern China. An intermediate crustal composition with a SiO2 content of 59.7 wt% has been estimated. However, there exists a significant lateral variation in the crustal structures among the tectonic units of eastern China. The structure and composition features of some regions in eastern China indicate that extension has played an important role in the continental crust evolution of eastern China.展开更多
C. acuminata seedlings cultivated in greenhouse were transplanted into the fields with 5 designed planting densities (11, 16, 25,44 and 100 plants·m^-2) in May of 2004 and were harvested in the middle of Septembe...C. acuminata seedlings cultivated in greenhouse were transplanted into the fields with 5 designed planting densities (11, 16, 25,44 and 100 plants·m^-2) in May of 2004 and were harvested in the middle of September of 2004. The seedling growth indexes including plant height and crown width, biomass allocation, camptothecin (CPT) content and CPT yield of different organs (young leaf, old leaf, stem,and root) were studied. For the 5 selected planting densities, the plant biomass, height, crown width, and total leaf area of C. acuminata seedlings all showed highest values at the planting density of 25 plants ·m^-2. CPT content in young leaves was higher than that in other organs of seedlings and presented an obvious change with the variation of planting densities and with the highest value at density of 100plants·m-2, while for other organs no significant variation in CPT content was found with change of planting density. The accumulation of CPT was enhanced significantly at the planting density of 25 plants·m^-2. It is concluded that for the purpose to get raw materials with more CPT from C. acuminata, the optimal planting density of C. acuminata seedlings should be designed as 25 plants·m^-2.展开更多
Atrazine chlorohydrolase gene (atzA) was cloned from Arthrobacter sp. AD1. A plant expression plasmid was constructed under the control of CaMV35s promoter and was used in rice transformation. The target gene was succ...Atrazine chlorohydrolase gene (atzA) was cloned from Arthrobacter sp. AD1. A plant expression plasmid was constructed under the control of CaMV35s promoter and was used in rice transformation. The target gene was successfully introduced into mature embryos of a japonica rice cultivar Jindao 107 by Agrobacterium- mediated transformation and hundreds of transgenic plants were obtained. The exogenous atzA gene in the transgenic plants that expressed atrazine resistance was confirmed by Southern blot hybridization. The resistance experiments by spraying transgenic rice plants with 0.133% atrazine shown that most of the transgenic rice plants exhibited the resistance to herbicide atrazine. The segregation of exogenous atzA gene in T1 progeny corresponded to the Mendelian ratio.展开更多
The Bernoulli convolution ν λ measure is shown to be absolutely continuous with L 2 density for almost all 12<λ<1,and singular if λ -1 is a Pisot number. It is an open question whether the Pisot typ...The Bernoulli convolution ν λ measure is shown to be absolutely continuous with L 2 density for almost all 12<λ<1,and singular if λ -1 is a Pisot number. It is an open question whether the Pisot type Bernoulli convolutions are the only singular ones. In this paper,we construct a family of non-Pisot type Bernoulli convolutions ν λ such that their density functions,if they exist,are not L 2. We also construct other Bernolulli convolutions whose density functions,if they exist,behave rather badly.展开更多
On December 3rd, 2011, China Population Welfare Foundation Mercy Fund was launched in the Great Hall of People in Beijing. The Fund is establishe with the aim to improve child education,
In the new era of agricultural development, irrigation and water conservancy construction has played a vital role, greatly improving the level of agricultural development in our country and providing sufficient impetu...In the new era of agricultural development, irrigation and water conservancy construction has played a vital role, greatly improving the level of agricultural development in our country and providing sufficient impetus for the realization of modern agricultural construction. Therefore, the rapid development of irrigation and water conservancy construction has achieved effective results and brought many benefits to the agricultural production in the new era. However, the current development of irrigation and water conservancy construction is still facing many difficulties. Therefore, it is necessary to fully understand the significance of irrigation and water conservancy construction to agricultural production, conduct in-depth research and analysis on the existing problems at this stage, and put forward effective countermeasures to solve the difficulties in the development of irrigation and water conservancy construction.展开更多
基金supported by grants from the National Natural Science Foundation of China(No.40104003)China Post-doctoral Science Foundationthe Chinese Academy of Sciences K.C.Wong Post-doctoral Research Award
文摘On the basis of a one-by-one latitude-longitude grid three-dimensional seismic velocity model, the crustal P-wave velocity structure in eastern China (105-125°E and 18-41°N) is obtained, and a set of geotherms for each grid is established for P-T correction on P-wave velocities. The average depths of sub-crustal layers and their average P-wave velocities of 18 tectonic units in eastern China are exhibited. Our result presents a 32-34 km thick crust beneath eastern China, which is thinner than previous studies, with an average velocity of 6.54 km/s, corresponding to a 5 kg/m3 variation in crustal mean density. The thicker upper but thinner middle and lower crust results in a lower average seismic velocity of eastern China. An intermediate crustal composition with a SiO2 content of 59.7 wt% has been estimated. However, there exists a significant lateral variation in the crustal structures among the tectonic units of eastern China. The structure and composition features of some regions in eastern China indicate that extension has played an important role in the continental crust evolution of eastern China.
基金This paper was supported by the National Natural Science Foundation of China (No.3970086) and Heilongjiang Province Foundation for Distinguished Youth Scholars (JC-02-11)
文摘C. acuminata seedlings cultivated in greenhouse were transplanted into the fields with 5 designed planting densities (11, 16, 25,44 and 100 plants·m^-2) in May of 2004 and were harvested in the middle of September of 2004. The seedling growth indexes including plant height and crown width, biomass allocation, camptothecin (CPT) content and CPT yield of different organs (young leaf, old leaf, stem,and root) were studied. For the 5 selected planting densities, the plant biomass, height, crown width, and total leaf area of C. acuminata seedlings all showed highest values at the planting density of 25 plants ·m^-2. CPT content in young leaves was higher than that in other organs of seedlings and presented an obvious change with the variation of planting densities and with the highest value at density of 100plants·m-2, while for other organs no significant variation in CPT content was found with change of planting density. The accumulation of CPT was enhanced significantly at the planting density of 25 plants·m^-2. It is concluded that for the purpose to get raw materials with more CPT from C. acuminata, the optimal planting density of C. acuminata seedlings should be designed as 25 plants·m^-2.
基金This work was suppored by the Natural Foundation of Tianjin,China(013066 11)the Agricultural Bio—technology Center ofTianjin,China(00312201l一4).
文摘Atrazine chlorohydrolase gene (atzA) was cloned from Arthrobacter sp. AD1. A plant expression plasmid was constructed under the control of CaMV35s promoter and was used in rice transformation. The target gene was successfully introduced into mature embryos of a japonica rice cultivar Jindao 107 by Agrobacterium- mediated transformation and hundreds of transgenic plants were obtained. The exogenous atzA gene in the transgenic plants that expressed atrazine resistance was confirmed by Southern blot hybridization. The resistance experiments by spraying transgenic rice plants with 0.133% atrazine shown that most of the transgenic rice plants exhibited the resistance to herbicide atrazine. The segregation of exogenous atzA gene in T1 progeny corresponded to the Mendelian ratio.
文摘The Bernoulli convolution ν λ measure is shown to be absolutely continuous with L 2 density for almost all 12<λ<1,and singular if λ -1 is a Pisot number. It is an open question whether the Pisot type Bernoulli convolutions are the only singular ones. In this paper,we construct a family of non-Pisot type Bernoulli convolutions ν λ such that their density functions,if they exist,are not L 2. We also construct other Bernolulli convolutions whose density functions,if they exist,behave rather badly.
文摘On December 3rd, 2011, China Population Welfare Foundation Mercy Fund was launched in the Great Hall of People in Beijing. The Fund is establishe with the aim to improve child education,
文摘In the new era of agricultural development, irrigation and water conservancy construction has played a vital role, greatly improving the level of agricultural development in our country and providing sufficient impetus for the realization of modern agricultural construction. Therefore, the rapid development of irrigation and water conservancy construction has achieved effective results and brought many benefits to the agricultural production in the new era. However, the current development of irrigation and water conservancy construction is still facing many difficulties. Therefore, it is necessary to fully understand the significance of irrigation and water conservancy construction to agricultural production, conduct in-depth research and analysis on the existing problems at this stage, and put forward effective countermeasures to solve the difficulties in the development of irrigation and water conservancy construction.
