Monodispersed MoS_2 nanospheres were successfully synthesized by using SiO_2 as hard template. The size and morphology of the MoS_2 nanospheres could be finely controlled by the content of SiO_2 and sulfur precursors....Monodispersed MoS_2 nanospheres were successfully synthesized by using SiO_2 as hard template. The size and morphology of the MoS_2 nanospheres could be finely controlled by the content of SiO_2 and sulfur precursors. Furthermore, higher surface area of monodispersed MoS_2 nanospheres exhibited high reaction rate for hydrodesulfurization(HDS) of dibenzenethiophene(DBT).展开更多
Comminution of coal to ultrafine sizes by high-pressure waterjet provides a novel method for preparation of coal-water fuels for next generation,near-zero emission electric power generation.The particle size distribut...Comminution of coal to ultrafine sizes by high-pressure waterjet provides a novel method for preparation of coal-water fuels for next generation,near-zero emission electric power generation.The particle size distribution(PSD)of ground coal is a key parameter in the preparation of slurries as it determines the settling behavior of the particles and viscosity of the coal-water mixture.There are several methods available for representation and evaluation of particle size analysis data.However,fractal theory provides a means by which the entire PSD of comminuted materials can be quantified by using of a specific and exact value.In this paper,a volume-based fractal model was deduced to characterize the PSD of the coal which is ground in a specially designed comminution cell.During the size reduction process,the inlet pressures up to 276 MPa were used.展开更多
Open-loop flow control method was used to affect the development of a turbulent wake behind a D-shaped bluff body.Loud speakers were embedded inside the bluff body to produce two zero-net-massflux jets through 2 mm-wi...Open-loop flow control method was used to affect the development of a turbulent wake behind a D-shaped bluff body.Loud speakers were embedded inside the bluff body to produce two zero-net-massflux jets through 2 mm-wide span-wise slots located along the upper and lower edges on the rear wall.The drag forces for different actuation amplitudes(C_μ the ratio between the momentum of the actuating jets and the moment deficit caused by the bluff body) and frequencies(Sr_A) were examined.The effects of the phase difference in the two jets(0 and π) were also studied.It was found that when C_μ was 0.1%,a drag reduction up to 5%was achieved when the velocities of the two jets varied in phase at a frequency of St_A = 0.16.When the velocities of the two jets varied rr out of phase,significant drag increase was observed.展开更多
Background: Passerida is the largest avian radiation within the order Passeriformes. Current understanding of the high-level relationships within Passerida is based on DNA–DNA hybridizations; however, the phylogeneti...Background: Passerida is the largest avian radiation within the order Passeriformes. Current understanding of the high-level relationships within Passerida is based on DNA–DNA hybridizations; however, the phylogenetic relationships within this assemblage have been the subject of many debates.Methods: We analyzed the 12 S ribosomal RNA gene from 49 species of Passerida, representing 14 currently recognized families, to outline the phylogenetic relationships within this group.Results: Our results identified the monophyly of the three superfamilies in Passerida: Sylvioidea, Muscicapoidea and Passeroidea. However, current delimitation of some species is at variance with our phylogeny estimate. First, the Parus major, which had been placed as a distinct clade sister to Sylvioidea was identified as a member of the super family;second, the genus Regulus was united with the Sturnidae and nested in the Muscicapoidea clade instead of being a clade of Passerida.Conclusion: Our results were consistent with Johansson's study of the three superfamilies except for the al ocation of two families, Paridae and Regulidae.展开更多
In order to study the roles of members of HKT gene family in wheat,TaH KT2; 2 was isolated by using homologous cloning strategy and screening genomic BAC library. TaHKT2; 2 genes were mapped on chromosomes 7 A,7 B and...In order to study the roles of members of HKT gene family in wheat,TaH KT2; 2 was isolated by using homologous cloning strategy and screening genomic BAC library. TaHKT2; 2 genes were mapped on chromosomes 7 A,7 B and 7 D,named as TaHKT2; 2-7 A,TaHKT2; 2-7 B,and TaHKT2; 2-7 D,respectively.TaHKT2; 2 and TaHKT2; 1 had the same genetic structure,composed of three exons and two introns,and formed a cluster with TaHKT2; 1 on the phylogenetic tree of plant HKT transporters. The coding sequences of TaHKT2; 2-7 A,TaHKT2; 2-7 B,and TaHKT2; 2-7 D were 1 602,1 602 and 1 596 bp long,respectively,but TaHKT2; 2-7 D cDNA sequence was not isolated by RT-PCR in eight wheat varieties. The natural diversity of TaHKT2; 2 genes was analyzed by cloning and sequencing from 12 wheat varieties. The results showed that TaHKT2; 2-7 A was found to be more diverse than TaHKT2; 2-7 B and TaHKT2; 2-7 D. Only a few bases changed in the alleles of TaH KT2; 2 genes in wheat. No amino-acid natural variation lay in the P-loops of deduced protein sequences of all alleles of TaHKT2;2 in 12 wheat varieties. The identity of coding sequences was much higher than that of 5' flanking regions of TaHKT2; 2 genes. TaHKT2; 2 might be selected over the course of wheat domestication and belonged to domestication gene.展开更多
基金Supported by the National Natural Science Foundation of China(21503023,21373034,U1463210)Hubei Key Lab of Novel Reactor&Green Chemical Technology,Key Laboratory for Green Chemical Process of Ministry of Education,School of Chemical Engineering and Pharmacy,Changzhou Science and Technology Bureau,Changzhou Key Laboratory of Respiratory System(CM20133005)Jiangsu Province Key and Advanced Laboratory of Catalytic Material and Technology in Changzhou University in Jiangsu Province,and Natural Science Fund of Changzhou Institute of Technology(YN1502,E3-6107-15-026)
文摘Monodispersed MoS_2 nanospheres were successfully synthesized by using SiO_2 as hard template. The size and morphology of the MoS_2 nanospheres could be finely controlled by the content of SiO_2 and sulfur precursors. Furthermore, higher surface area of monodispersed MoS_2 nanospheres exhibited high reaction rate for hydrodesulfurization(HDS) of dibenzenethiophene(DBT).
基金supported by the Missouri University of Science and Technology/Waterjet Laboratory and funded by the China Postdoctoral Science Foundation(Grant No.2014M552555XB)Doctoral Program in Xi’an University of Science and Technology(Grant No.2013QDJ039).
文摘Comminution of coal to ultrafine sizes by high-pressure waterjet provides a novel method for preparation of coal-water fuels for next generation,near-zero emission electric power generation.The particle size distribution(PSD)of ground coal is a key parameter in the preparation of slurries as it determines the settling behavior of the particles and viscosity of the coal-water mixture.There are several methods available for representation and evaluation of particle size analysis data.However,fractal theory provides a means by which the entire PSD of comminuted materials can be quantified by using of a specific and exact value.In this paper,a volume-based fractal model was deduced to characterize the PSD of the coal which is ground in a specially designed comminution cell.During the size reduction process,the inlet pressures up to 276 MPa were used.
基金supported by the National Basic Research Program(2014CB744100)State Key Laboratory of Aerodynamics(SKLA20130102)Dalian University of Technology(DUT14LK07)
文摘Open-loop flow control method was used to affect the development of a turbulent wake behind a D-shaped bluff body.Loud speakers were embedded inside the bluff body to produce two zero-net-massflux jets through 2 mm-wide span-wise slots located along the upper and lower edges on the rear wall.The drag forces for different actuation amplitudes(C_μ the ratio between the momentum of the actuating jets and the moment deficit caused by the bluff body) and frequencies(Sr_A) were examined.The effects of the phase difference in the two jets(0 and π) were also studied.It was found that when C_μ was 0.1%,a drag reduction up to 5%was achieved when the velocities of the two jets varied in phase at a frequency of St_A = 0.16.When the velocities of the two jets varied rr out of phase,significant drag increase was observed.
基金supported by the National Natural Science Foundation of China (NSFC, 31000191, 31330073)the Postdoctoral Science Foundation of China (2011 M500537)+2 种基金the Natural Science Foundation of Hebei Province (NSFHB, 2012205018)the Natural Science Foundation of the Department of Education, Hebei Province (YQ2014024) to D. LiNSFHB (2013205018) to Y. Wu
文摘Background: Passerida is the largest avian radiation within the order Passeriformes. Current understanding of the high-level relationships within Passerida is based on DNA–DNA hybridizations; however, the phylogenetic relationships within this assemblage have been the subject of many debates.Methods: We analyzed the 12 S ribosomal RNA gene from 49 species of Passerida, representing 14 currently recognized families, to outline the phylogenetic relationships within this group.Results: Our results identified the monophyly of the three superfamilies in Passerida: Sylvioidea, Muscicapoidea and Passeroidea. However, current delimitation of some species is at variance with our phylogeny estimate. First, the Parus major, which had been placed as a distinct clade sister to Sylvioidea was identified as a member of the super family;second, the genus Regulus was united with the Sturnidae and nested in the Muscicapoidea clade instead of being a clade of Passerida.Conclusion: Our results were consistent with Johansson's study of the three superfamilies except for the al ocation of two families, Paridae and Regulidae.
基金Supported by National Key Research and Development Program of China(2016YFD0101802)Modern Agricultural Science and Technology Innovation Engineering Project of Hebei Province(2017038997)National Natural Science Foundation of Hebei Province(C2014106075)
文摘In order to study the roles of members of HKT gene family in wheat,TaH KT2; 2 was isolated by using homologous cloning strategy and screening genomic BAC library. TaHKT2; 2 genes were mapped on chromosomes 7 A,7 B and 7 D,named as TaHKT2; 2-7 A,TaHKT2; 2-7 B,and TaHKT2; 2-7 D,respectively.TaHKT2; 2 and TaHKT2; 1 had the same genetic structure,composed of three exons and two introns,and formed a cluster with TaHKT2; 1 on the phylogenetic tree of plant HKT transporters. The coding sequences of TaHKT2; 2-7 A,TaHKT2; 2-7 B,and TaHKT2; 2-7 D were 1 602,1 602 and 1 596 bp long,respectively,but TaHKT2; 2-7 D cDNA sequence was not isolated by RT-PCR in eight wheat varieties. The natural diversity of TaHKT2; 2 genes was analyzed by cloning and sequencing from 12 wheat varieties. The results showed that TaHKT2; 2-7 A was found to be more diverse than TaHKT2; 2-7 B and TaHKT2; 2-7 D. Only a few bases changed in the alleles of TaH KT2; 2 genes in wheat. No amino-acid natural variation lay in the P-loops of deduced protein sequences of all alleles of TaHKT2;2 in 12 wheat varieties. The identity of coding sequences was much higher than that of 5' flanking regions of TaHKT2; 2 genes. TaHKT2; 2 might be selected over the course of wheat domestication and belonged to domestication gene.
文摘准确进行周期识别对于合理认识水文变异规律、开展中长期水文模拟预报、水安全评价等具有重要的意义.本文通过滑动改变周期长度和初相位,构造出多组模拟周期序列,并以相关系数作为模拟周期序列与原始序列拟合精度的判别指标,选择拟合程度最好的模拟周期作为最优周期识别结果,从而提出水文序列滑动周期识别方法.理论和公式推导表明:相关系数可表征水文序列中的周期波动程度,相关系数越大,说明拟合精度越高,对应的周期变异越显著.统计试验结果显示:相比于常用的周期识别方法,文中方法的周期识别效率更高,且在各因素影响下也最具稳定性和可靠性.最后,文中方法应用于澜沧江流域21个站的年降雨量序列进行周期识别,结果显示该流域的降雨周期存在多时间尺度特征,北部和中部的降雨周期长度较短,多数在2~5 a左右,而南部的降雨周期5~10 a居多,个别站点的周期长度达到了18 a.
