The multiple filamentation of terawatt femtosecond (fs) laser pulses is experimentally studied in a natural environment. A more than 30-m long plasma filament with a millimeter diameter is formed by the collimated f...The multiple filamentation of terawatt femtosecond (fs) laser pulses is experimentally studied in a natural environment. A more than 30-m long plasma filament with a millimeter diameter is formed by the collimated fs laser pulse freely propagating in an open atmosphere. This study provides the first quantitative experimental data about the electron density of a long range light filament in the atmosphere. The electron density of such a filament is quantitatively detected by using an electric method, showing that it is at the 1011-cm -3 level.展开更多
We demonstrate a high-quality cross-polarized-wave filter based on spectral phase modulation. Driven by Well- eompressed spectral-phase fully-compensated fundamental laser lmlses, the filter stretches the pulse bandwi...We demonstrate a high-quality cross-polarized-wave filter based on spectral phase modulation. Driven by Well- eompressed spectral-phase fully-compensated fundamental laser lmlses, the filter stretches the pulse bandwidth from 35 nm to 7Ohm with a conversion efficeiency of 20%.展开更多
[Objectives]This study was conducted to compare and analyze the chemical constituents of the volatile oils of the Yao medicine Thunbergia grandiflora from different habitats.[Methods]A quartz capillary column DB-1MS,a...[Objectives]This study was conducted to compare and analyze the chemical constituents of the volatile oils of the Yao medicine Thunbergia grandiflora from different habitats.[Methods]A quartz capillary column DB-1MS,an EI ion source and a quadrupole mass analyzer were used for analysis.The chromatographic and mass spectrum information obtained was automatically retrieved and analyzed by data processing system and its memory spectrum library(Nist.08).The relative content of each chemical component in the volatile oil was determined by the peak area normalization method.[Results]Forty nine chromatographic peaks were isolated from the sample produced in Shitun,Bailongtan Town,Mashan County,and 24 chemical constituents were identified,accounting for 88.78% of the total volatile oil.Forty nine chromatographic peaks were isolated from the sample produced in Hongdu Village,Chengjiang Town,Duan County,and 30 chemical constituents were identified,accounting for 88.38% of the total volatile oil.Forty eight chromatographic peaks were isolated from the sample produced in Longwan Township,Du'an County,and 25 chemical constituents were identified,accounting for 80.01% of the total volatile oil.Nine chemical constituents were common to the volatile oils of the samples from the three habitats.[Conclusions]It could be seen that the main components of volatile oils from T.grandiflora produced in different areas are different.展开更多
Structures with single gradient and dual gradients have been designed and fabricated in an Al_(0.5)Cr_(0.9)FeNi_(2.5)V_(0.2) medium entropy alloy.Structures with dual gradients(with increasing grain size and a decreas...Structures with single gradient and dual gradients have been designed and fabricated in an Al_(0.5)Cr_(0.9)FeNi_(2.5)V_(0.2) medium entropy alloy.Structures with dual gradients(with increasing grain size and a decreasing volume fraction of nanoprecipitates from the surface to the center)were observed to show much better dynamic shear properties compared to both structures with single grainsize gradient and coarse-grained structures with homogeneously distributed nanoprecipitates.Thus,the dual gradients have a synergetic strengthening/toughening effect as compared to the sole effect of a single gradient and the sole precipitation effect.Initiation of the adiabatic shear band(ASB)is delayed and propagation of ASB is slowed down in structures with dual gradients compared to structures with single gradients,resulting in better dynamic shear properties.A higher magnitude of strain gradient and higher density of geometrically necessary dislocations are induced in the structures with dual gradients,resulting in extra strain hardening.Higher density dislocations,stacking faults,and Lomer-Cottrell locks can be accumulated by the interactions between these defects and B2/L1_(2) precipitates,due to the higher volume fraction of nanoprecipitates in the surface layer of the structures with dual gradients,which could retard the early strain localization in the surface layer for better dynamic shear properties.展开更多
It has been well established that the gut microbiota has a substantial influence on the host immune system.By crosstalk between specific microorganism-associated molecular patterns and the immune system,in addition to...It has been well established that the gut microbiota has a substantial influence on the host immune system.By crosstalk between specific microorganism-associated molecular patterns and the immune system,in addition to bacterial metabolic activity,gut microbiota regulates local or systemic inflammation(1).Recently,the composition of gut microbiota has been presumed to be one of the factors affecting the cancer-immune set point of cancer patients,which subsequently determines the efficacy of immune checkpoint inhibitor(ICI)treatment(2).展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11574387,11404335,11474002,and 11535001)the National Basic Research Program of China(Grant Nos.2013CBA01501 and 2013CB922401)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grants Nos.XDB16010200 and XDB07030300)the Science Challenge Project,China(Grant No.TZ2016005)
文摘The multiple filamentation of terawatt femtosecond (fs) laser pulses is experimentally studied in a natural environment. A more than 30-m long plasma filament with a millimeter diameter is formed by the collimated fs laser pulse freely propagating in an open atmosphere. This study provides the first quantitative experimental data about the electron density of a long range light filament in the atmosphere. The electron density of such a filament is quantitatively detected by using an electric method, showing that it is at the 1011-cm -3 level.
基金Supported by the National Key Basic Research Program of China under Grant No 2013CB922402the National Natural Science Foundation of China under Grant Nos 61575217 and 11434016+1 种基金the Key Research Program of Frontier Sciences of Chinese Academy of Sciences under Grant Nos KJZD-EW-L11-03 and QYZDJ-SSW-JSC006the Strategic Priority Research Program of Chinese Academy of Sciences under Grant No XDB16030200
文摘We demonstrate a high-quality cross-polarized-wave filter based on spectral phase modulation. Driven by Well- eompressed spectral-phase fully-compensated fundamental laser lmlses, the filter stretches the pulse bandwidth from 35 nm to 7Ohm with a conversion efficeiency of 20%.
基金Supported by Undergraduate Innovation and Entrepreneurship Project of Department of Education of Guangxi Zhuang Autonomous Region(No:201813643063).
文摘[Objectives]This study was conducted to compare and analyze the chemical constituents of the volatile oils of the Yao medicine Thunbergia grandiflora from different habitats.[Methods]A quartz capillary column DB-1MS,an EI ion source and a quadrupole mass analyzer were used for analysis.The chromatographic and mass spectrum information obtained was automatically retrieved and analyzed by data processing system and its memory spectrum library(Nist.08).The relative content of each chemical component in the volatile oil was determined by the peak area normalization method.[Results]Forty nine chromatographic peaks were isolated from the sample produced in Shitun,Bailongtan Town,Mashan County,and 24 chemical constituents were identified,accounting for 88.78% of the total volatile oil.Forty nine chromatographic peaks were isolated from the sample produced in Hongdu Village,Chengjiang Town,Duan County,and 30 chemical constituents were identified,accounting for 88.38% of the total volatile oil.Forty eight chromatographic peaks were isolated from the sample produced in Longwan Township,Du'an County,and 25 chemical constituents were identified,accounting for 80.01% of the total volatile oil.Nine chemical constituents were common to the volatile oils of the samples from the three habitats.[Conclusions]It could be seen that the main components of volatile oils from T.grandiflora produced in different areas are different.
基金supported by the National Natural Science Foundation of China (Nos.52192591,12202459,and 11790293)the NSFC Basic Science Center Program for“Multiscale Problems in Nonlinear Mechanics” (No.11988102)the fellowship of China Postdoctoral Science Foundation (No.2021M703292).
文摘Structures with single gradient and dual gradients have been designed and fabricated in an Al_(0.5)Cr_(0.9)FeNi_(2.5)V_(0.2) medium entropy alloy.Structures with dual gradients(with increasing grain size and a decreasing volume fraction of nanoprecipitates from the surface to the center)were observed to show much better dynamic shear properties compared to both structures with single grainsize gradient and coarse-grained structures with homogeneously distributed nanoprecipitates.Thus,the dual gradients have a synergetic strengthening/toughening effect as compared to the sole effect of a single gradient and the sole precipitation effect.Initiation of the adiabatic shear band(ASB)is delayed and propagation of ASB is slowed down in structures with dual gradients compared to structures with single gradients,resulting in better dynamic shear properties.A higher magnitude of strain gradient and higher density of geometrically necessary dislocations are induced in the structures with dual gradients,resulting in extra strain hardening.Higher density dislocations,stacking faults,and Lomer-Cottrell locks can be accumulated by the interactions between these defects and B2/L1_(2) precipitates,due to the higher volume fraction of nanoprecipitates in the surface layer of the structures with dual gradients,which could retard the early strain localization in the surface layer for better dynamic shear properties.
基金We thank Dr.Tianye Li for the language editing assistance.Funding:This work was supported by the National Natural Science Foundation of China(No.81572608,81874120,81672984)the Wuhan Science and Technology Bureau(No.2017060201010170).
文摘It has been well established that the gut microbiota has a substantial influence on the host immune system.By crosstalk between specific microorganism-associated molecular patterns and the immune system,in addition to bacterial metabolic activity,gut microbiota regulates local or systemic inflammation(1).Recently,the composition of gut microbiota has been presumed to be one of the factors affecting the cancer-immune set point of cancer patients,which subsequently determines the efficacy of immune checkpoint inhibitor(ICI)treatment(2).