Magnetic refrigeration is a revolutionary, efficient, environmentally friendly cooling technology, which is on the threshold of commercialization. The magnetic rare earth materials are utilized as the magnetic refrige...Magnetic refrigeration is a revolutionary, efficient, environmentally friendly cooling technology, which is on the threshold of commercialization. The magnetic rare earth materials are utilized as the magnetic refrigerants in most cooling devices, and for many cooling application the Nd2Fe14B permanent magnets are employed as the source of the magnetic field. The status of the near room temperature magnetic cooling was reviewed.展开更多
[Objective] The study was to analyze the phylogenesis of Anas platyrhynchos. [Method] Complete sequence of mitochondrial ND2 gene of 4 Anas platyrhynchos was determined by direct DNA sequencing based on PCR products. ...[Objective] The study was to analyze the phylogenesis of Anas platyrhynchos. [Method] Complete sequence of mitochondrial ND2 gene of 4 Anas platyrhynchos was determined by direct DNA sequencing based on PCR products. Combined with ND2 gene sequences of the Anas Linnaeus accessed in GenBank, phylogenetic tree was constructed by Neighbor-joining and maximum parsimony methods. [Result] The ND2 gene sequences of 4 Anas platyrhynchos were identical(1 041 bp in length; the nucleotide contents of A, G, T, and C were 28.91%, 13.35%, 20.75% and 36.98% respectively; A+T content approximated to that of C+G). Sequences of ND2 gene of mallard were same as spotbill duck, and had high homology with others. The phylogenetic trees indicated mallard and spotbilled duck were close in genetic relationship, both shared a haplotype; then Philippine duck, green-winged teal and northern pintail fell into branch ''A". [Conclusion] The domestic duck may be domesticated from mallard and spotbilled duck.展开更多
We describe a new species of the genus Tylototriton from Ingyin Taung Mt.,Mohnyin Township,Kachin State,Myanmar,based on morphological and molecular evidence.The new species is assigned to the subgenus Tylototriton s....We describe a new species of the genus Tylototriton from Ingyin Taung Mt.,Mohnyin Township,Kachin State,Myanmar,based on morphological and molecular evidence.The new species is assigned to the subgenus Tylototriton s.str.and is clearly distinct from all known congeners by the following characters:medium body size;thin,long tail,lacking lateral grooves;rough skin;truncate snout;wide,protruding supratemporal bony ridges on head,beginning at anterior corner of orbit;weak,almost indistinct sagittal ridge;long,thin limbs,broadly overlapping when adpressed along body;distinct,wide,non-segmented vertebral ridge;13 or 14 rib nodules;brown to darkbrown background coloration with dull orange-brown to yellowish-brown markings on labial regions,parotoids,rib nodules,whole limbs,vent,and ventral tail ridge.We also briefly discuss biogeography and species diversity of the genus Tylototriton in Myanmar.展开更多
The red swamp crayfish,Procambarus clarkii,is a native species in north-eastern Mexico and south-central USA.P.clarkii was introduced to China in 1929 and has been used as an aquaculture species in China since 1983.It...The red swamp crayfish,Procambarus clarkii,is a native species in north-eastern Mexico and south-central USA.P.clarkii was introduced to China in 1929 and has been used as an aquaculture species in China since 1983.It currently exists in most of the provinces of China,but threatens local fish,crustaceans,aquatic plants and local freshwater ecosystems.We examined the genetic variation in partial mitochondrial ND2 gene of 831 individuals collected from 25 P.clarkii populations in 13 provinces of China to infer the expansion pathways and mechanisms.Six haplotypes were detected.All six haplotypes appeared in four populations in Nanjing and a population located near Nanjing whereas only 1–5 of the six haplotypes were present in other populations.These data suggest that the populations in Nanjing are probably the source of all other populations in China.There were no significant relationships between geographic distances and genetic distances in 25 populations,whereas significant relationship was found in four populations in Qinhuai River covering 50 km in Nanjing.These data suggest that the expansion mainly be human-mediated in large scale,and active disposal or non-anthropogenic passive dispersal might have played an important role in expansion at a smaller scale.In some places far away from Nanjing,several haplotypes existed,suggested multiple introduction events may have happened.Although aquaculture of this species could bring huge economic benefit,its potential to negatively affect native biota and entire ecosystems should not be ignored.展开更多
The complete mitochondrial NADH dehydrogenase subunit 2(ND2) gene sequences of two species of Thermophis, T. baileyi and T. zhaoermii, were sequenced and compared to those of 86 sequences from other snakes(74 from Cae...The complete mitochondrial NADH dehydrogenase subunit 2(ND2) gene sequences of two species of Thermophis, T. baileyi and T. zhaoermii, were sequenced and compared to those of 86 sequences from other snakes(74 from Caenophidia and 12 from Henophidia). By using Bayesian inference(BI) and maximum likehood(ML) approaches, Thermophis was demonstrated as the sister group to the North American relicts of Dipsadinae, and rooted in Central and South American members of this subfamily. The results suggest that the closest relatives of Thermophis are the North American relicts, and thus support the hypothesis for an Asian-North American origin of xenodontine snakes as suggested by Vidal et al.(2000). Extensive sampling of Asian snakes and American dipsadines is needed to further test this hypothesis in the future.展开更多
The melting behavior,solid state phase transformation and structure of pseudo-ternary compounds Nd_2(Fe_(1-x)Ni_x)_(14)B and Pr_2(Co_(1-y)Ni_y)_(14)B were studied using differential thermal analysis,optical microscopy...The melting behavior,solid state phase transformation and structure of pseudo-ternary compounds Nd_2(Fe_(1-x)Ni_x)_(14)B and Pr_2(Co_(1-y)Ni_y)_(14)B were studied using differential thermal analysis,optical microscopy X-ray diffraction,and electron probe micro-analysis techniques.At high temperature,eutectoid decomposition R_2(Ni,M)_(17)→R(Ni,M)_5+x-Ni(M) takes place in these two pseudo-ternary compounds,in the composition range x=0.6～1.0 and y=0.3～1.0,respectively.When x(or y)≤0.2,both Nd_2(Fe_(1-x)Ni_x)_(14)B and Pr_2(Co_(1-y)Ni_y)_(14)B are single phase tetragonal.The phase constitutents of these two systems at room tempera- ture are similar in the composition range 0.6≤x(or y)≤1.0.展开更多
基金Project supported bythe U.S .Department of Energy ,Office of Basic Energy Sciences , Materials Science and Engineering Division and Astronautics Corporation of America , Milwaukee , Wisconsin
文摘Magnetic refrigeration is a revolutionary, efficient, environmentally friendly cooling technology, which is on the threshold of commercialization. The magnetic rare earth materials are utilized as the magnetic refrigerants in most cooling devices, and for many cooling application the Nd2Fe14B permanent magnets are employed as the source of the magnetic field. The status of the near room temperature magnetic cooling was reviewed.
基金Supported by National Key Technology R&D program(2006BAD06B06)National Infrastructure of Natural Resources for Science and Technology(2004DKA30460)~~
文摘[Objective] The study was to analyze the phylogenesis of Anas platyrhynchos. [Method] Complete sequence of mitochondrial ND2 gene of 4 Anas platyrhynchos was determined by direct DNA sequencing based on PCR products. Combined with ND2 gene sequences of the Anas Linnaeus accessed in GenBank, phylogenetic tree was constructed by Neighbor-joining and maximum parsimony methods. [Result] The ND2 gene sequences of 4 Anas platyrhynchos were identical(1 041 bp in length; the nucleotide contents of A, G, T, and C were 28.91%, 13.35%, 20.75% and 36.98% respectively; A+T content approximated to that of C+G). Sequences of ND2 gene of mallard were same as spotbill duck, and had high homology with others. The phylogenetic trees indicated mallard and spotbilled duck were close in genetic relationship, both shared a haplotype; then Philippine duck, green-winged teal and northern pintail fell into branch ''A". [Conclusion] The domestic duck may be domesticated from mallard and spotbilled duck.
基金partially supported by the Russian Science Foundation(19-14-00050)
文摘We describe a new species of the genus Tylototriton from Ingyin Taung Mt.,Mohnyin Township,Kachin State,Myanmar,based on morphological and molecular evidence.The new species is assigned to the subgenus Tylototriton s.str.and is clearly distinct from all known congeners by the following characters:medium body size;thin,long tail,lacking lateral grooves;rough skin;truncate snout;wide,protruding supratemporal bony ridges on head,beginning at anterior corner of orbit;weak,almost indistinct sagittal ridge;long,thin limbs,broadly overlapping when adpressed along body;distinct,wide,non-segmented vertebral ridge;13 or 14 rib nodules;brown to darkbrown background coloration with dull orange-brown to yellowish-brown markings on labial regions,parotoids,rib nodules,whole limbs,vent,and ventral tail ridge.We also briefly discuss biogeography and species diversity of the genus Tylototriton in Myanmar.
基金The research was funded by the internal fund of the Temasek Life Sciences Laboratory(Fund number:5020).
文摘The red swamp crayfish,Procambarus clarkii,is a native species in north-eastern Mexico and south-central USA.P.clarkii was introduced to China in 1929 and has been used as an aquaculture species in China since 1983.It currently exists in most of the provinces of China,but threatens local fish,crustaceans,aquatic plants and local freshwater ecosystems.We examined the genetic variation in partial mitochondrial ND2 gene of 831 individuals collected from 25 P.clarkii populations in 13 provinces of China to infer the expansion pathways and mechanisms.Six haplotypes were detected.All six haplotypes appeared in four populations in Nanjing and a population located near Nanjing whereas only 1–5 of the six haplotypes were present in other populations.These data suggest that the populations in Nanjing are probably the source of all other populations in China.There were no significant relationships between geographic distances and genetic distances in 25 populations,whereas significant relationship was found in four populations in Qinhuai River covering 50 km in Nanjing.These data suggest that the expansion mainly be human-mediated in large scale,and active disposal or non-anthropogenic passive dispersal might have played an important role in expansion at a smaller scale.In some places far away from Nanjing,several haplotypes existed,suggested multiple introduction events may have happened.Although aquaculture of this species could bring huge economic benefit,its potential to negatively affect native biota and entire ecosystems should not be ignored.
基金funded by the National Natural Science Foundation of China(30870290,31071891)the Students Science Research Program of Huangshan University(2010xdkj012)
文摘The complete mitochondrial NADH dehydrogenase subunit 2(ND2) gene sequences of two species of Thermophis, T. baileyi and T. zhaoermii, were sequenced and compared to those of 86 sequences from other snakes(74 from Caenophidia and 12 from Henophidia). By using Bayesian inference(BI) and maximum likehood(ML) approaches, Thermophis was demonstrated as the sister group to the North American relicts of Dipsadinae, and rooted in Central and South American members of this subfamily. The results suggest that the closest relatives of Thermophis are the North American relicts, and thus support the hypothesis for an Asian-North American origin of xenodontine snakes as suggested by Vidal et al.(2000). Extensive sampling of Asian snakes and American dipsadines is needed to further test this hypothesis in the future.
基金the National Natural Science Fundation of China.
文摘The melting behavior,solid state phase transformation and structure of pseudo-ternary compounds Nd_2(Fe_(1-x)Ni_x)_(14)B and Pr_2(Co_(1-y)Ni_y)_(14)B were studied using differential thermal analysis,optical microscopy X-ray diffraction,and electron probe micro-analysis techniques.At high temperature,eutectoid decomposition R_2(Ni,M)_(17)→R(Ni,M)_5+x-Ni(M) takes place in these two pseudo-ternary compounds,in the composition range x=0.6～1.0 and y=0.3～1.0,respectively.When x(or y)≤0.2,both Nd_2(Fe_(1-x)Ni_x)_(14)B and Pr_2(Co_(1-y)Ni_y)_(14)B are single phase tetragonal.The phase constitutents of these two systems at room tempera- ture are similar in the composition range 0.6≤x(or y)≤1.0.
