In order to obtain an effective and reliable grain refiner for Mg-Al alloys, 1% （mass fraction） Mg3N2 was added into AZ31 Mg alloy. The microstructures of the Mg alloys were studied by optical microscopy, scan elect...In order to obtain an effective and reliable grain refiner for Mg-Al alloys, 1% （mass fraction） Mg3N2 was added into AZ31 Mg alloy. The microstructures of the Mg alloys were studied by optical microscopy, scan electron microscopy and X-ray energy dispersive spectroscopy, and the mechanical properties were determined. The results show that adding a small amount of Mg3N2 to AZ31 Mg alloy can refine the grain size from 103 to 58 μm. The ultimate tensile strength and elongation of AZ31 Mg alloy are 174.1MPa and 8.3%, respectively. After the addition of 1% Mg3N2, the ultimate tensile strength and elongation of AZ31 Mg alloy are increased up to 198.7 MPa and 11.8%, respectively. The grain refinement mechanism is that AIN is formed after Mg3N2 is added. Both AIN and Mg phases are of HCP lattice structure, and the disregistry between Mg phases and AIN along （0001）Mg//（0001）AIN is 3.04%, which is very effective for heterogeneous nucleation.展开更多
The thyroid hormones L-thyroxine and triiodo-L-thyronine have profound effects on postembryonic development of most vertebrates. Analysis of their action in mammals is vitiated by the exposure of the developing foetus...The thyroid hormones L-thyroxine and triiodo-L-thyronine have profound effects on postembryonic development of most vertebrates. Analysis of their action in mammals is vitiated by the exposure of the developing foetus to a number of maternal factors which do not allow one to specifically define the role of thyroid hormone (TH)or that of other hormones and factors that modulate its action. Amphibian metamorphosis is obligatorily dependent on TH which can initiate all the diverse physiological manifestations of this postembryonic developmental process(morphogenesis, cell death, re-structuring, etc.) in free-living embryos and larvae of most anurans. This article will first describe the salient features of metamorphosis and its control by TH and other hormones. Emphasis will be laid on the key role played by TH receptor (TR), in particular the phenomenon of TR gene autoinduction, in initiating the developmental action of TH. Finally, it will be argued that the findings on the control of amphibian metamorphosis enhance our understanding of the regulation of postembryonic development by TH in other vertebrate species.展开更多
As a very important component of a coastal system, tidal flats come to be a focus of the studies on land-ocean interaction in the coastal zone because those areas are subjected to intense human activities and are high...As a very important component of a coastal system, tidal flats come to be a focus of the studies on land-ocean interaction in the coastal zone because those areas are subjected to intense human activities and are highly sensitive to the global change. The Quanzhou Bay, located along the middle part of Fujian coast of China, covers about 136.4km^2, and the area of coastal wetland in the entire bay from intertidal to subtidal with 6m of water depth accounts for 96% of the total area. Seven short cores were collected and divided in situ with the interval of 5cm on the coastal wetlands of Quanzhou Bay on April 19, 2006. The sediment samples were scattered and the grain sizes were measured by using Mastersizer 2000. Human beings＇ activities on tidal fiat have disturbed the vertical distribution of sediments in stratigraphic sequence and accelerated the sedimentation rates. Grain size analysis results show that the grain size diameters increase and sediment becomes worse sorted towards the sea under the strong human disturbance; Spartina alterniflora can play a role of trapping the fine sediment; but near the bank, the sediment becomes coarse and there are two peak values on frequency curve influenced by the sandpile. The trough formed by human activities along the coastline changes the transport path of water and suspended sediment. The sediments are transported through the trough and deposit in it during the flood; the ebb flow is retarded by the flow output through the adjacent trough, and the deposited sediment can not be re-suspended; then, the sedimentation rate increases. In situ observation show that the sedimentation rate is about 8-10cm/yr.展开更多
In this paper, we conduct research on the gender discrimination phenomenon and the primary cause in English and Chinese language. Language is a social phenomenon, so the restriction of the society but the culture is t...In this paper, we conduct research on the gender discrimination phenomenon and the primary cause in English and Chinese language. Language is a social phenomenon, so the restriction of the society but the culture is the foundation of the survival and development of human society cannot leave the culture at the same time. Due to physiological differences, men in the social practice play a more important role than woman burdened with a family. We analyze the gender discrimination phenomenon from different unique perspective to eventually understand the mechanism. In the future, we will combine the literature review to modify our proposed methodology.展开更多
Euphemism, as the linguistic and cultural phenomenon, is a lubricant in linguistic communication used in different aspects of social lives. With the rapid development of science and progress of human civilization, eup...Euphemism, as the linguistic and cultural phenomenon, is a lubricant in linguistic communication used in different aspects of social lives. With the rapid development of science and progress of human civilization, euphemism, as one of the most important components in English language, has the tendency of multiplying. This paper, based on the development of euphemism in modem American English, sums up the basic features of euphemism in modem American English and analyzes its formation and application in modem American society and culture with the objective of improving learners＇ communication ability in the context of cross cultural communication.展开更多
Chinese idioms are the essence of the Chinese language, the crystallization of human wisdom and the important cartier of national culture. Through the structure, content and meaning of Chinese idioms, we can see vario...Chinese idioms are the essence of the Chinese language, the crystallization of human wisdom and the important cartier of national culture. Through the structure, content and meaning of Chinese idioms, we can see various forms of the history and culture of the Han nationality. Observe national culture through the structure, content, meaning of Chinese idioms, namely the phenomenon of the linguistic phenomenon and culture phenomenon, we focus on elaborating Chinese idioms and cultural relationship between a Chinese idiom and Chinese culture.展开更多
An experiment was conducted and through distant hybridization a new promising forms of citruses were obtained. Namely, after hybridization of lemon Georgian and broad-leaved mandarin unshiu （mother components） with ...An experiment was conducted and through distant hybridization a new promising forms of citruses were obtained. Namely, after hybridization of lemon Georgian and broad-leaved mandarin unshiu （mother components） with early-ripening trifoliata and a hybrid of citrus ichangensis--＂Caucasus＂ （father components） a wide range of nucellar seedlings were obtained. It should be noted that nucellar seedlings of hybrid nature are practically closer to distant hybrids of sexual origin that are sharply inclined to the side of the mother component and produce good quality fruit. Unfortunately, such hybrids are either very rare or cannot be obtained at all. While, in the case of the study, through using new combinations in hybridization, the possibility of getting nucellar seedlings of the hybrid nature is much bigger. Distant hybridization turned out to be particularly interesting because of the polyembryony of citrus plants. Due to this, it gives opportunity to get new promising forms not only from the egg cell but from nucellar cells as well.展开更多
基金Project(2007430023)supported by the Office of Education,Henan Province,ChinaProject(0612002500)supported by the Excellent Young Scientists Foundation of Henan Province,China
文摘In order to obtain an effective and reliable grain refiner for Mg-Al alloys, 1% （mass fraction） Mg3N2 was added into AZ31 Mg alloy. The microstructures of the Mg alloys were studied by optical microscopy, scan electron microscopy and X-ray energy dispersive spectroscopy, and the mechanical properties were determined. The results show that adding a small amount of Mg3N2 to AZ31 Mg alloy can refine the grain size from 103 to 58 μm. The ultimate tensile strength and elongation of AZ31 Mg alloy are 174.1MPa and 8.3%, respectively. After the addition of 1% Mg3N2, the ultimate tensile strength and elongation of AZ31 Mg alloy are increased up to 198.7 MPa and 11.8%, respectively. The grain refinement mechanism is that AIN is formed after Mg3N2 is added. Both AIN and Mg phases are of HCP lattice structure, and the disregistry between Mg phases and AIN along （0001）Mg//（0001）AIN is 3.04%, which is very effective for heterogeneous nucleation.
文摘The thyroid hormones L-thyroxine and triiodo-L-thyronine have profound effects on postembryonic development of most vertebrates. Analysis of their action in mammals is vitiated by the exposure of the developing foetus to a number of maternal factors which do not allow one to specifically define the role of thyroid hormone (TH)or that of other hormones and factors that modulate its action. Amphibian metamorphosis is obligatorily dependent on TH which can initiate all the diverse physiological manifestations of this postembryonic developmental process(morphogenesis, cell death, re-structuring, etc.) in free-living embryos and larvae of most anurans. This article will first describe the salient features of metamorphosis and its control by TH and other hormones. Emphasis will be laid on the key role played by TH receptor (TR), in particular the phenomenon of TR gene autoinduction, in initiating the developmental action of TH. Finally, it will be argued that the findings on the control of amphibian metamorphosis enhance our understanding of the regulation of postembryonic development by TH in other vertebrate species.
基金Under the auspices of the National Natural Science Foundation of China(No.40606012)the Marine Science Youth Fund of State Oceanic Administration of China(No.2006312)the Natural Science Foundation of Fujian Province(No.D0510025)
文摘As a very important component of a coastal system, tidal flats come to be a focus of the studies on land-ocean interaction in the coastal zone because those areas are subjected to intense human activities and are highly sensitive to the global change. The Quanzhou Bay, located along the middle part of Fujian coast of China, covers about 136.4km^2, and the area of coastal wetland in the entire bay from intertidal to subtidal with 6m of water depth accounts for 96% of the total area. Seven short cores were collected and divided in situ with the interval of 5cm on the coastal wetlands of Quanzhou Bay on April 19, 2006. The sediment samples were scattered and the grain sizes were measured by using Mastersizer 2000. Human beings＇ activities on tidal fiat have disturbed the vertical distribution of sediments in stratigraphic sequence and accelerated the sedimentation rates. Grain size analysis results show that the grain size diameters increase and sediment becomes worse sorted towards the sea under the strong human disturbance; Spartina alterniflora can play a role of trapping the fine sediment; but near the bank, the sediment becomes coarse and there are two peak values on frequency curve influenced by the sandpile. The trough formed by human activities along the coastline changes the transport path of water and suspended sediment. The sediments are transported through the trough and deposit in it during the flood; the ebb flow is retarded by the flow output through the adjacent trough, and the deposited sediment can not be re-suspended; then, the sedimentation rate increases. In situ observation show that the sedimentation rate is about 8-10cm/yr.
文摘In this paper, we conduct research on the gender discrimination phenomenon and the primary cause in English and Chinese language. Language is a social phenomenon, so the restriction of the society but the culture is the foundation of the survival and development of human society cannot leave the culture at the same time. Due to physiological differences, men in the social practice play a more important role than woman burdened with a family. We analyze the gender discrimination phenomenon from different unique perspective to eventually understand the mechanism. In the future, we will combine the literature review to modify our proposed methodology.
文摘Euphemism, as the linguistic and cultural phenomenon, is a lubricant in linguistic communication used in different aspects of social lives. With the rapid development of science and progress of human civilization, euphemism, as one of the most important components in English language, has the tendency of multiplying. This paper, based on the development of euphemism in modem American English, sums up the basic features of euphemism in modem American English and analyzes its formation and application in modem American society and culture with the objective of improving learners＇ communication ability in the context of cross cultural communication.
文摘Chinese idioms are the essence of the Chinese language, the crystallization of human wisdom and the important cartier of national culture. Through the structure, content and meaning of Chinese idioms, we can see various forms of the history and culture of the Han nationality. Observe national culture through the structure, content, meaning of Chinese idioms, namely the phenomenon of the linguistic phenomenon and culture phenomenon, we focus on elaborating Chinese idioms and cultural relationship between a Chinese idiom and Chinese culture.
文摘An experiment was conducted and through distant hybridization a new promising forms of citruses were obtained. Namely, after hybridization of lemon Georgian and broad-leaved mandarin unshiu （mother components） with early-ripening trifoliata and a hybrid of citrus ichangensis--＂Caucasus＂ （father components） a wide range of nucellar seedlings were obtained. It should be noted that nucellar seedlings of hybrid nature are practically closer to distant hybrids of sexual origin that are sharply inclined to the side of the mother component and produce good quality fruit. Unfortunately, such hybrids are either very rare or cannot be obtained at all. While, in the case of the study, through using new combinations in hybridization, the possibility of getting nucellar seedlings of the hybrid nature is much bigger. Distant hybridization turned out to be particularly interesting because of the polyembryony of citrus plants. Due to this, it gives opportunity to get new promising forms not only from the egg cell but from nucellar cells as well.
