ABSTRACT Introduction:Mushroom poisoning was the leading cause of foodborne disease outbreaks and outbreak-associated deaths in China.Mushroom poisoning outbreak surveillance can provide insight into the epidemiologic...ABSTRACT Introduction:Mushroom poisoning was the leading cause of foodborne disease outbreaks and outbreak-associated deaths in China.Mushroom poisoning outbreak surveillance can provide insight into the epidemiological characteristics of mushroom poisonings and guide policymaking and health education to reduce illnesses and deaths.Methods:Foodborne Disease Outbreak Surveillance System was upgraded in 2011 to collect foodborne disease outbreaks in China.Mushroom poisoning outbreaks during 2010–2020 were selected to analyze geographical distribution,seasonal distribution,and setting of food preparation.Results:A total of 10,036 outbreaks,which resulted in 38,676 illnesses and 788 deaths,were reported in this period.Mushroom poisonings occurred all over the country,but with highest incidence in the southwest and central China.展开更多
Wild rice species is an important source of useful genes for cultivated rice improvement Some accessions of Oryza eichingeri (In = 24, CC) from Africa confer strong resistance to brown planthopper (BPH), whitebacked p...Wild rice species is an important source of useful genes for cultivated rice improvement Some accessions of Oryza eichingeri (In = 24, CC) from Africa confer strong resistance to brown planthopper (BPH), whitebacked planthopper (WBPH) and bacterial blight (KB). In the present study, restriction fragments length polymorphism (RFLP) and simple sequence repeats (SSR) analysis were performed on disomic backcross plants between Oryza saliva (2n =24, AA) and O. eichingeri in order to identify the presence of O, eichingeri segments and further to localize BPH-resistant gene. In the introgression lines, 1-6 O. eichingeri segments were detected on rice chromosomes 1, 2, 6, or/and 10. The dominant BPH resistant gene, tentatively named Bphl3(t), was mapped to chromosome 2, being 6.1 and 5.5 cM away from two microsatellite markers RM240 and RM250, respectively. The transfer and localization of this gene from O. eichingeri will contribute to the improvement of BPH resistance in cultivated rice.展开更多
The SG-Ⅲlaser facility(SG-Ⅲ)is the largest laser driver for inertial confinement fusion(ICF)researches in China,which has 48 beamlines and can deliver 180 kJ ultraviolet laser energy in 3 ns.In order to meet the req...The SG-Ⅲlaser facility(SG-Ⅲ)is the largest laser driver for inertial confinement fusion(ICF)researches in China,which has 48 beamlines and can deliver 180 kJ ultraviolet laser energy in 3 ns.In order to meet the requirements of precise physics experiments,some new functionalities need to be added to SG-Ⅲand some intrinsic laser performances need upgrade.So at the end of SG-Ⅲ's engineering construction,the 2-year laser performance upgrade project started.This paper will introduce the newly added functionalities and the latest laser performance of SG-Ⅲ.With these function extensions and performance upgrade,SG-Ⅲis now fully prepared for precise ICF experiments and solidly paves the way towards fusion ignition.展开更多
A method of slope reliability analysis was developed by imposing a state equation on the limit equilibrium theory, given the basis of a fixed safety factor technique. Among the many problems of reliability analysis, t...A method of slope reliability analysis was developed by imposing a state equation on the limit equilibrium theory, given the basis of a fixed safety factor technique. Among the many problems of reliability analysis, the most important problem is to find a performance function. We have created a new method of building a limit state equation for planar slip surfaces by applying the mathematical cusp catastrophe theory. This new technique overcomes the defects in the traditional rigid limit equilibrium theory and offers a new way for studying the reliability problem of planar slip surfaces. Consequently, we applied the technique to a case of an open-pit mine and compared our results with that of the traditional approach. From the results we conclude that both methods are essentially consistent, but the reliability index calculated by the traditional model is lower than that from the catastrophic model. The catastrophe model takes into consideration two possible situations of a slope being in the limit equilibrium condition, i.e., it may or may not slip. In the traditional method, however, a slope is definitely considered as slipping when it meets the condition of a limit equilibrium. We conclude that the catastrophe model has more actual and instructive importance compared to the traditional model.展开更多
Dendrobium officinale,an important medicinal plant of the genus Dendrobium in Orchidaceae family,has been used as traditional Chinese medicine(TCM)for nearly thousands of years.Here,we report the first chromosome-leve...Dendrobium officinale,an important medicinal plant of the genus Dendrobium in Orchidaceae family,has been used as traditional Chinese medicine(TCM)for nearly thousands of years.Here,we report the first chromosome-level reference genome of D.officinale,based on Pac Bio long-reads,Illumina short-reads and HiC data.The high-quality assembled genome is 1.23 Gb long,with contig N50 of 1.44 Mb.A total of 93.53%genome sequences were assembled into 19 pseudochromosomes with a super scaffold N50 of 63.07 Mb.Through comparative genomic analysis,we explored the expanded gene families of D.officinale,and also their impact on environmental adaptation and biosynthesis of secondary metabolites.We further performed detailed transcriptional analysis of D.officinale,and identified the candidate genes involved in the biosynthesis of three main active ingredients,including polysaccharides,alkaloids and flavonoids.In addition,the MODIFYING WALL LIGNIN-1(MWL1)gene,which inferred from Genome-Wide Association Studies(GWAS)based on the resequencing date from D.officinale and five related species and their morphologic features,may contribute to the plant production(yield of stems)of D.officinale.Therefore,the high-quality reference genome reported in this study could benefits functional genomics research and molecular breeding of D.officinale.展开更多
In this paper, the leader-following tracking problem of fractional-order multi-agent systems is addressed. The dynamics of each agent may be heterogeneous and has unknown nonlinearities. By assumptions that the intera...In this paper, the leader-following tracking problem of fractional-order multi-agent systems is addressed. The dynamics of each agent may be heterogeneous and has unknown nonlinearities. By assumptions that the interaction topology is undirected and connected and the unknown nonlinear uncertain dynamics can be parameterized by a neural network, an adaptive learning law is proposed to deal with unknown nonlinear dynamics, based on which a kind of cooperative tracking protocols are constructed. The feedback gain matrix is obtained to solve an algebraic Riccati equation. To construct the fully distributed cooperative tracking protocols, the adaptive law is also adopted to adjust the coupling weight. With the developed control laws,we can prove that all signals in the closed-loop systems are guaranteed to be uniformly ultimately bounded. Finally, a simple simulation example is provided to illustrate the established result.展开更多
SG-Ⅲ laser facility is now the largest laser driver for inertial confinement fusion research in China. The whole laser facility can deliver 180 kJ energy and 60 TW power ultraviolet laser onto target, with power bala...SG-Ⅲ laser facility is now the largest laser driver for inertial confinement fusion research in China. The whole laser facility can deliver 180 kJ energy and 60 TW power ultraviolet laser onto target, with power balance better than 10%.We review the laser system and introduce the SG-Ⅲ laser performance here.展开更多
This paper contributes to extracting information from signals of broadband ultrasonic attenuation spectrum for effective utilization in particle size characterization. The single particle scattering model and the coup...This paper contributes to extracting information from signals of broadband ultrasonic attenuation spectrum for effective utilization in particle size characterization. The single particle scattering model and the coupled-phase model are formulated simultaneously, the relationship between particle size distribution and ultrasonic spectrum is established, and a convergence criterion for calculation is quantified. Demonstration inversion by the optimum regularization factor method is carried out to yield typical numerical results for discussion. With the experimental set-up developed by the Institute of Particle and Two-Phase Flow Measurement (IPTFM) at the University of Shanghai for Science and Technology, sand sediment particle size is measured by attenuation spectrum and analyzed using the above inversion algorithm and theoretical models. To validate the proposed ultrasonic spectrum particle sizing method, results are compared with those obtained by microscopy.展开更多
Owing to its great medicinal and ornamental values, Dendrobium officinale is frequently adulterated with other Dendrobium species on the market. Unfortunately, the utilization of the common DNA markers ITS,ITS2, and m...Owing to its great medicinal and ornamental values, Dendrobium officinale is frequently adulterated with other Dendrobium species on the market. Unfortunately, the utilization of the common DNA markers ITS,ITS2, and mat Ktrbc L is unable to distinguish D. officinale from 5 closely related species of it(D. tosaense, D.shixingense, D. flexicaule, D. scoriarum and D. aduncum). Here, we compared 63 Dendrobium plastomes comprising 40 newly sequenced plastomes of the 6 species and 23 previously published plastomes. The plastomes of D. officinale and its closely related species were shown to have conserved genome structure and gene content. Comparative analyses revealed that small single copy region contained higher variation than large single copy and inverted repeat regions, which was mainly attributed to the loss/retention of ndh genes.Furthermore, the intraspecific sequence variability among different Dendrobium species was shown to be diversified, which necessitates a cautious evaluation of genetic markers specific for different Dendrobium species.By evaluating the maximum likelihood trees inferred from different datasets, we found that the complete plastome sequence dataset had the highest discriminatory power for D. officinale and its closely related species,indicating that complete plastome sequences can be used to accurately authenticate Dendrobium species.& 2018 Chinese Pharmaceutical Association and Institute of Materia Medica, Chinese Academy of Medical Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license(http://creativecommons.org/licenses/by-nc-nd/4.0/).展开更多
During the Yangtze Freshwater Dolphin Expedition 2012,Yangtze finless porpoises(Neophocaena asiaeorientalis)were acoustically monitored in 9 port areas at night.During 6566 min of nocturnal monitoring,porpoise sonar w...During the Yangtze Freshwater Dolphin Expedition 2012,Yangtze finless porpoises(Neophocaena asiaeorientalis)were acoustically monitored in 9 port areas at night.During 6566 min of nocturnal monitoring,porpoise sonar was detected for 488 min(7.43%of the total time).Of all 81 encounters,the longest echolocation span obtained was 102.9 min,suggesting frequent and prolonged porpoise occupation of the port areas.A combined total of 2091 click trains were recorded,with 129(6.2%)containing minimum inter-click intervals(ICIs)below 10 ms(termed a buzz).Buzzes with a decrease in ICIs and search and approach phases that resembled feeding echolocation signals accounted for 44.2%(N=52)of all buzzes.Buzzes with an increase in ICIs,suggesting a mirrored prey capture phase,accounted for 20.2%(N=26)and could reflect attempts to locate escaped prey because they were followed by approach-phase feeding buzzes.Anecdotal evidence of porpoises fleeing the proximity of vessels was observed.The recordings indicating clusters of porpoises feeding near the port areas suggest a forced choice for feeding due to the relatively higher prey availability in the port areas compared to other areas in the Yangtze River that are probably overfished.展开更多
An improved delayed detached eddy simulation （IDDES） method based on the k-x-SST （shear stress transport） turbulence model was applied to predict the unsteady vortex breakdown past an 80o/65o double-delta wing （...An improved delayed detached eddy simulation （IDDES） method based on the k-x-SST （shear stress transport） turbulence model was applied to predict the unsteady vortex breakdown past an 80o/65o double-delta wing （DDW）, where the angles of attack （AOAs） range from 30° to 40°. Firstly, the IDDES model and the relative numerical methods were validated by simulating the massively separated flow around an NACA0021 straight wing at the AOA of 60°. The fluctuation properties of the lift and pressure coefficients were analyzed and compared with the available measurements. For the DDW case, the computations were compared with such mea-surements as the mean lift, drag, pitching moment, pressure coefficients and breakdown locations. Furthermore, the unsteady properties were investigated in detail, such as the frequencies of force and moments, pressure fluctuation on the upper surface, typical vortex breakdown patterns at three moments, and the distributions of kinetic turbulence energy at a stream wise section. Two dominated modes are observed, in which their Strouhal numbers are 1.0 at the AOAs of 30°, 32° and 34° and 0.7 at the AOAs of 36o, 38° and 40°. The breakdown vortex always moves upstream and downstream and its types change alternatively. Furthermore, the vortex can be identified as breakdown or not through the mean pressure, root mean square of pressure, or even through correlation analysis.展开更多
A noise-sidebands-free and ultra-low relative intensity noise(RIN) 1.5 μm single-frequency fiber laser is demonstrated for the first time to our best knowledge. Utilizing a self-injection locking framework and a boos...A noise-sidebands-free and ultra-low relative intensity noise(RIN) 1.5 μm single-frequency fiber laser is demonstrated for the first time to our best knowledge. Utilizing a self-injection locking framework and a booster optical amplifier, the noise sidebands with relative amplitudes as high as 20 dB are completely suppressed.The RIN is remarkably reduced by more than 64 dB at the relaxation oscillation peak to retain below-150 dB∕Hz in a frequency range from 75 kHz to 50 MHz, while the quantum noise limit is -152.9 d B∕Hz.Furthermore, a laser linewidth narrower than 600 Hz, a polarization-extinction ratio of more than 23 dB, and an optical signal-to-noise ratio of more than 73 dB are acquired simultaneously. This noise-sidebands-free and ultralow-RIN single-frequency fiber laser is highly competitive in advanced coherent light detection fields including coherent Doppler wind lidar, high-speed coherent optical communication, and precise absolute distance coherent measurement.展开更多
Walsh-Hadamard transform （WriT） can solve linear error equations on Field F2, and the method can be used to recover the parameters of convolutional code. However, solving the equations with many unknowns needs enorm...Walsh-Hadamard transform （WriT） can solve linear error equations on Field F2, and the method can be used to recover the parameters of convolutional code. However, solving the equations with many unknowns needs enormous computer memory which limits the application of WriT. In order to solve this problem, a method based on segmented WriT is proposed in this paper. The coefficient vector of high dimension is reshaped and two vectors of lower dimension are obtained. Then the WriT is operated and the requirement for computer memory is much reduced. The code rate and the constraint length of convolutional code are detected from the Walsh spectrum. And the check vector is recovered from the peak position. The validity of the method is verified by the simulation result, and the performance is proved to be optimal.展开更多
Based on a partial postcranial skeleton collected from the Lower Cretaceous Napai Formation of Guangxi, China, we erect a new sauropod taxon, Fusuisaurus zhaoi gen. et sp. nov. The holotype specimen consists of the le...Based on a partial postcranial skeleton collected from the Lower Cretaceous Napai Formation of Guangxi, China, we erect a new sauropod taxon, Fusuisaurus zhaoi gen. et sp. nov. The holotype specimen consists of the left ilium, left pubis, anterior caudals, most of the dorsal ribs and distal end of the left femur. Fusuisaurus zhaoi is diagnosed by a unique combination of character states among the known sauropods. It displays several synapomorphies of Titanosauriformes but lacks many derived features seen in other titanosauriforms, suggesting that the new taxon represents the basalmost known titanosauriform and providing new evidence that Titanosauriformes originated from Asia. A size comparison suggests that Fusuisaurus zhaoi is among the largest Early Cretaceous sauropods, providing an important addition to the Early Cretaceous Chinese sauropod diversity.展开更多
A rotating pre-twisted and inclined cantilever beam model (RPICBM) with the flapwise-chordwise-axial-torsional coupling is established with the Hamilton principle and the finite element (FE) method. The effectiveness ...A rotating pre-twisted and inclined cantilever beam model (RPICBM) with the flapwise-chordwise-axial-torsional coupling is established with the Hamilton principle and the finite element (FE) method. The effectiveness of the model is verified via comparisons with the literatures and the FE models in ANSYS. The effects of the setting and pre-twisted angles on the dynamic responses of the RPICBM are analyzed. The results show that:(i) the increase in the setting or pre-twisted angle results in the increases in the first-order flapwise and torsional frequencies while the decrease in the first-order chordwise frequency under rotating conditions;(ii) a positive/negative setting angle leads to a positive/negative constant component, while a positive/negative pre-twisted angle leads to a negative/positive constant component;(iii) when the rotation speed is non-zero, the pre-twisted angle or non-zero setting angle will result in the coupled flapwise-chordwiseaxial- torsional vibration of the RPICBM under axial base excitation.展开更多
This paper deals with the blind separation of nonstation-ary sources and direction-of-arrival （DOA） estimation in the under-determined case, when there are more sources than sensors. We assume the sources to be time...This paper deals with the blind separation of nonstation-ary sources and direction-of-arrival （DOA） estimation in the under-determined case, when there are more sources than sensors. We assume the sources to be time-frequency （TF） disjoint to a certain extent. In particular, the number of sources presented at any TF neighborhood is strictly less than that of sensors. We can identify the real number of active sources and achieve separation in any TF neighborhood by the sparse representation method. Compared with the subspace-based algorithm under the same sparseness assumption, which suffers from the extra noise effect since it can-not estimate the true number of active sources, the proposed algorithm can estimate the number of active sources and their cor-responding TF values in any TF neighborhood simultaneously. An-other contribution of this paper is a new estimation procedure for the DOA of sources in the underdetermined case, which combines the TF sparseness of sources and the clustering technique. Sim-ulation results demonstrate the validity and high performance of the proposed algorithm in both blind source separation （BSS） and DOA estimation.展开更多
Frost heave experiments on saturated sandstone and tuff with an open crack are conducted under uniform and unidirectional freezing conditions.Frost heave of crack in sandstone with high permeability is more significan...Frost heave experiments on saturated sandstone and tuff with an open crack are conducted under uniform and unidirectional freezing conditions.Frost heave of crack in sandstone with high permeability is more significant under uniform freezing condition than that under unidirectional freezing condition.However,frost heave of crack in tuff with low permeability is more significant under unidirectional freezing condition.To illustrate the reasons for this phenomenon,a numerical model on the freezing processes of saturated rock with an open crack considering the latent heat of pore water and water in crack is proposed and confirmed to be reliable.Numerical results show that a frozen shell that blocks the migration of water in crack to rock develops first in the outer part of the rock before the freezing of water in crack under unifonn freezing condition.However,the migration path of water in crack to the unfrozen rock under freezing front exists under unidirectional freezing condition.The freezing process and permeability of rock together determine the migration of water in crack and lead to the different frost heave modes of crack for various permeable rocks under different freezing conditions.The frost heave modes of crack in rock with low or high permeability are similar under uniform freezing condition because water migration is blocked by a frozen shell and is irrelevant to rock permeability.For high permeability rock,the frost heave of crack will be weakened due to water migration under unidirectional freezing condition;however,the frost heave of crack would be more significant for low permeability rock because water migration is blocked under unidirectional freezing condition.Therefore,the freezing condition and rock permeability determine the frost heave of rock with crack together,and this should be concerned in cold regions engineering applications.展开更多
We study the determinants of China ＇s bilateral local currency swap lines that were established following the recent global finance crisis. It is found that economic factors, political considerations and institutiona...We study the determinants of China ＇s bilateral local currency swap lines that were established following the recent global finance crisis. It is found that economic factors, political considerations and institutional characteristics, including trade intensity, economic size, strategic partnership, free trade agreements, corruption and stability, affect the decision to sign a swap line agreement. Once a swap line agreement decision is made, the size of the swap line is then mainly affected by trade intensity, economic size and the presence of a free trade agreement. The results are quite robust with respect to the choices of the Heckman two-stage framework or the proportional hazard model. The gravity effect captured by distances between China and its counterparts, if present, is mainly observed during the early part of the sample period under consideration.展开更多
Achyranthes bidentata and Achyranthes aspera are saponin and steroid rich medicinal plants, used extensively for therapeutic treatments in Traditional Chinese Medicine(TCM) and Ayurveda. A. bidentata is reported to be...Achyranthes bidentata and Achyranthes aspera are saponin and steroid rich medicinal plants, used extensively for therapeutic treatments in Traditional Chinese Medicine(TCM) and Ayurveda. A. bidentata is reported to be one of the rare and extensively exploited medicinal plant species that face the issue of being endangered.Finding qualitative substitute with identical phyto-constituents contributing to similar composition and pharmacological benefits will help in reducing the burden of exploitation of the natural habitats of such plants.In the present study, a comparative metabolite analysis of the whole drug and specific tissues isolated by laser micro-dissection(LMD) was carried out for both the selected species, by use of ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry(UHPLC-QTOF MS). The results of the study indicate that the cortex and the medullary ray tissues are rich in their content of steroidal and saponin constituents such as(25 S)-inokosterone-20,22-acetonide, ginsenoside Ro, bidentatoside II and achyranthoside B.Metabolite profiling of the whole tissues of both the species indicates presence of identical constituents. Thus,it is inferred that A. bidentata and A. aspera can be used as qualitative substitutes for each other.展开更多
基金The National Key Research and Development Program of China(Grant number 2017YFC1601503).
文摘ABSTRACT Introduction:Mushroom poisoning was the leading cause of foodborne disease outbreaks and outbreak-associated deaths in China.Mushroom poisoning outbreak surveillance can provide insight into the epidemiological characteristics of mushroom poisonings and guide policymaking and health education to reduce illnesses and deaths.Methods:Foodborne Disease Outbreak Surveillance System was upgraded in 2011 to collect foodborne disease outbreaks in China.Mushroom poisoning outbreaks during 2010–2020 were selected to analyze geographical distribution,seasonal distribution,and setting of food preparation.Results:A total of 10,036 outbreaks,which resulted in 38,676 illnesses and 788 deaths,were reported in this period.Mushroom poisonings occurred all over the country,but with highest incidence in the southwest and central China.
文摘Wild rice species is an important source of useful genes for cultivated rice improvement Some accessions of Oryza eichingeri (In = 24, CC) from Africa confer strong resistance to brown planthopper (BPH), whitebacked planthopper (WBPH) and bacterial blight (KB). In the present study, restriction fragments length polymorphism (RFLP) and simple sequence repeats (SSR) analysis were performed on disomic backcross plants between Oryza saliva (2n =24, AA) and O. eichingeri in order to identify the presence of O, eichingeri segments and further to localize BPH-resistant gene. In the introgression lines, 1-6 O. eichingeri segments were detected on rice chromosomes 1, 2, 6, or/and 10. The dominant BPH resistant gene, tentatively named Bphl3(t), was mapped to chromosome 2, being 6.1 and 5.5 cM away from two microsatellite markers RM240 and RM250, respectively. The transfer and localization of this gene from O. eichingeri will contribute to the improvement of BPH resistance in cultivated rice.
基金This work is supported by the SG-Ⅲ performance upgrade project.
文摘The SG-Ⅲlaser facility(SG-Ⅲ)is the largest laser driver for inertial confinement fusion(ICF)researches in China,which has 48 beamlines and can deliver 180 kJ ultraviolet laser energy in 3 ns.In order to meet the requirements of precise physics experiments,some new functionalities need to be added to SG-Ⅲand some intrinsic laser performances need upgrade.So at the end of SG-Ⅲ's engineering construction,the 2-year laser performance upgrade project started.This paper will introduce the newly added functionalities and the latest laser performance of SG-Ⅲ.With these function extensions and performance upgrade,SG-Ⅲis now fully prepared for precise ICF experiments and solidly paves the way towards fusion ignition.
基金financial support from Changjiang Scholars and Innovative Research Team in University, and research project of ‘SUST Spring Bud’
文摘A method of slope reliability analysis was developed by imposing a state equation on the limit equilibrium theory, given the basis of a fixed safety factor technique. Among the many problems of reliability analysis, the most important problem is to find a performance function. We have created a new method of building a limit state equation for planar slip surfaces by applying the mathematical cusp catastrophe theory. This new technique overcomes the defects in the traditional rigid limit equilibrium theory and offers a new way for studying the reliability problem of planar slip surfaces. Consequently, we applied the technique to a case of an open-pit mine and compared our results with that of the traditional approach. From the results we conclude that both methods are essentially consistent, but the reliability index calculated by the traditional model is lower than that from the catastrophic model. The catastrophe model takes into consideration two possible situations of a slope being in the limit equilibrium condition, i.e., it may or may not slip. In the traditional method, however, a slope is definitely considered as slipping when it meets the condition of a limit equilibrium. We conclude that the catastrophe model has more actual and instructive importance compared to the traditional model.
基金supported by grants from the National Natural Science Foundation of China(Grant No.31900268,31670330 and 32070353)Natural Science Foundation of Jiangsu Province,China(BK20190699)Natural science fund for colleges and universities in Jiangsu Province,China(19KJB180005)
文摘Dendrobium officinale,an important medicinal plant of the genus Dendrobium in Orchidaceae family,has been used as traditional Chinese medicine(TCM)for nearly thousands of years.Here,we report the first chromosome-level reference genome of D.officinale,based on Pac Bio long-reads,Illumina short-reads and HiC data.The high-quality assembled genome is 1.23 Gb long,with contig N50 of 1.44 Mb.A total of 93.53%genome sequences were assembled into 19 pseudochromosomes with a super scaffold N50 of 63.07 Mb.Through comparative genomic analysis,we explored the expanded gene families of D.officinale,and also their impact on environmental adaptation and biosynthesis of secondary metabolites.We further performed detailed transcriptional analysis of D.officinale,and identified the candidate genes involved in the biosynthesis of three main active ingredients,including polysaccharides,alkaloids and flavonoids.In addition,the MODIFYING WALL LIGNIN-1(MWL1)gene,which inferred from Genome-Wide Association Studies(GWAS)based on the resequencing date from D.officinale and five related species and their morphologic features,may contribute to the plant production(yield of stems)of D.officinale.Therefore,the high-quality reference genome reported in this study could benefits functional genomics research and molecular breeding of D.officinale.
基金supported by the National Natural Science Foundation of China(61303211)Zhejiang Provincial Natural Science Foundation of China(LY17F030003,LY15F030009)
文摘In this paper, the leader-following tracking problem of fractional-order multi-agent systems is addressed. The dynamics of each agent may be heterogeneous and has unknown nonlinearities. By assumptions that the interaction topology is undirected and connected and the unknown nonlinear uncertain dynamics can be parameterized by a neural network, an adaptive learning law is proposed to deal with unknown nonlinear dynamics, based on which a kind of cooperative tracking protocols are constructed. The feedback gain matrix is obtained to solve an algebraic Riccati equation. To construct the fully distributed cooperative tracking protocols, the adaptive law is also adopted to adjust the coupling weight. With the developed control laws,we can prove that all signals in the closed-loop systems are guaranteed to be uniformly ultimately bounded. Finally, a simple simulation example is provided to illustrate the established result.
文摘SG-Ⅲ laser facility is now the largest laser driver for inertial confinement fusion research in China. The whole laser facility can deliver 180 kJ energy and 60 TW power ultraviolet laser onto target, with power balance better than 10%.We review the laser system and introduce the SG-Ⅲ laser performance here.
基金National High Technology Development 863 Program(2006AA03Z349)National Science Foundation of China (50706029)Shang-hai Education Committee Foundation (07ZZ88)
文摘This paper contributes to extracting information from signals of broadband ultrasonic attenuation spectrum for effective utilization in particle size characterization. The single particle scattering model and the coupled-phase model are formulated simultaneously, the relationship between particle size distribution and ultrasonic spectrum is established, and a convergence criterion for calculation is quantified. Demonstration inversion by the optimum regularization factor method is carried out to yield typical numerical results for discussion. With the experimental set-up developed by the Institute of Particle and Two-Phase Flow Measurement (IPTFM) at the University of Shanghai for Science and Technology, sand sediment particle size is measured by attenuation spectrum and analyzed using the above inversion algorithm and theoretical models. To validate the proposed ultrasonic spectrum particle sizing method, results are compared with those obtained by microscopy.
基金supported by the National Natural Science Foundation of China (Grant Nos. 31170300 and 31670330)the Priority Academic Program Development of Jiangsu Higher Education Institutions to Xiaoyu Ding (Grant No. 2015-SWYY-014)
文摘Owing to its great medicinal and ornamental values, Dendrobium officinale is frequently adulterated with other Dendrobium species on the market. Unfortunately, the utilization of the common DNA markers ITS,ITS2, and mat Ktrbc L is unable to distinguish D. officinale from 5 closely related species of it(D. tosaense, D.shixingense, D. flexicaule, D. scoriarum and D. aduncum). Here, we compared 63 Dendrobium plastomes comprising 40 newly sequenced plastomes of the 6 species and 23 previously published plastomes. The plastomes of D. officinale and its closely related species were shown to have conserved genome structure and gene content. Comparative analyses revealed that small single copy region contained higher variation than large single copy and inverted repeat regions, which was mainly attributed to the loss/retention of ndh genes.Furthermore, the intraspecific sequence variability among different Dendrobium species was shown to be diversified, which necessitates a cautious evaluation of genetic markers specific for different Dendrobium species.By evaluating the maximum likelihood trees inferred from different datasets, we found that the complete plastome sequence dataset had the highest discriminatory power for D. officinale and its closely related species,indicating that complete plastome sequences can be used to accurately authenticate Dendrobium species.& 2018 Chinese Pharmaceutical Association and Institute of Materia Medica, Chinese Academy of Medical Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license(http://creativecommons.org/licenses/by-nc-nd/4.0/).
基金suported by grants from the Knowledge Innovation Program of Chinese Academy of Sciences(No.KSCX2-EW-Z-4)the National Natural Science Foundation of China(No.31170501 and 31070347)+1 种基金the Special Fund for Agro-scientific Research in the Public Interest of the Ministry of Agriculture of China(No.201203086)the Ocean Park Conservation Foundation,Hong Kong.Some logistic support was provided by Wuhan Baiji Conservation Foundation and Societe Generale de Surveillance S.A.Special thanks are also extended to the academic editor and anonymous reviewers for their helpful critique of an earlier version of this manuscript.
文摘During the Yangtze Freshwater Dolphin Expedition 2012,Yangtze finless porpoises(Neophocaena asiaeorientalis)were acoustically monitored in 9 port areas at night.During 6566 min of nocturnal monitoring,porpoise sonar was detected for 488 min(7.43%of the total time).Of all 81 encounters,the longest echolocation span obtained was 102.9 min,suggesting frequent and prolonged porpoise occupation of the port areas.A combined total of 2091 click trains were recorded,with 129(6.2%)containing minimum inter-click intervals(ICIs)below 10 ms(termed a buzz).Buzzes with a decrease in ICIs and search and approach phases that resembled feeding echolocation signals accounted for 44.2%(N=52)of all buzzes.Buzzes with an increase in ICIs,suggesting a mirrored prey capture phase,accounted for 20.2%(N=26)and could reflect attempts to locate escaped prey because they were followed by approach-phase feeding buzzes.Anecdotal evidence of porpoises fleeing the proximity of vessels was observed.The recordings indicating clusters of porpoises feeding near the port areas suggest a forced choice for feeding due to the relatively higher prey availability in the port areas compared to other areas in the Yangtze River that are probably overfished.
基金co-supported by Innovative Foundation of CARDCthe National Natural Science Foundation of China (No. 11072129)
文摘An improved delayed detached eddy simulation （IDDES） method based on the k-x-SST （shear stress transport） turbulence model was applied to predict the unsteady vortex breakdown past an 80o/65o double-delta wing （DDW）, where the angles of attack （AOAs） range from 30° to 40°. Firstly, the IDDES model and the relative numerical methods were validated by simulating the massively separated flow around an NACA0021 straight wing at the AOA of 60°. The fluctuation properties of the lift and pressure coefficients were analyzed and compared with the available measurements. For the DDW case, the computations were compared with such mea-surements as the mean lift, drag, pitching moment, pressure coefficients and breakdown locations. Furthermore, the unsteady properties were investigated in detail, such as the frequencies of force and moments, pressure fluctuation on the upper surface, typical vortex breakdown patterns at three moments, and the distributions of kinetic turbulence energy at a stream wise section. Two dominated modes are observed, in which their Strouhal numbers are 1.0 at the AOAs of 30°, 32° and 34° and 0.7 at the AOAs of 36o, 38° and 40°. The breakdown vortex always moves upstream and downstream and its types change alternatively. Furthermore, the vortex can be identified as breakdown or not through the mean pressure, root mean square of pressure, or even through correlation analysis.
基金National Natural Science Foundation of China(NSFC)(11674103,61535014,61635004)Major Program of the National Natural Science Foundation of China(61790582)+3 种基金Fundamental Research Funds for Central Universities(2015ZM091,2017BQ002)China National Funds for Distinguished Young Scientists(61325024)Natural Science Foundation of Guangdong Province(2016A030310410,2017A030310007)Science and Technology Project of Guangdong(2014B050505007,2015B090926010,2016B090925004,2017B090911005)
文摘A noise-sidebands-free and ultra-low relative intensity noise(RIN) 1.5 μm single-frequency fiber laser is demonstrated for the first time to our best knowledge. Utilizing a self-injection locking framework and a booster optical amplifier, the noise sidebands with relative amplitudes as high as 20 dB are completely suppressed.The RIN is remarkably reduced by more than 64 dB at the relaxation oscillation peak to retain below-150 dB∕Hz in a frequency range from 75 kHz to 50 MHz, while the quantum noise limit is -152.9 d B∕Hz.Furthermore, a laser linewidth narrower than 600 Hz, a polarization-extinction ratio of more than 23 dB, and an optical signal-to-noise ratio of more than 73 dB are acquired simultaneously. This noise-sidebands-free and ultralow-RIN single-frequency fiber laser is highly competitive in advanced coherent light detection fields including coherent Doppler wind lidar, high-speed coherent optical communication, and precise absolute distance coherent measurement.
基金supported by the National Natural Science Foundation of China(61072120)
文摘Walsh-Hadamard transform （WriT） can solve linear error equations on Field F2, and the method can be used to recover the parameters of convolutional code. However, solving the equations with many unknowns needs enormous computer memory which limits the application of WriT. In order to solve this problem, a method based on segmented WriT is proposed in this paper. The coefficient vector of high dimension is reshaped and two vectors of lower dimension are obtained. Then the WriT is operated and the requirement for computer memory is much reduced. The code rate and the constraint length of convolutional code are detected from the Walsh spectrum. And the check vector is recovered from the peak position. The validity of the method is verified by the simulation result, and the performance is proved to be optimal.
文摘Based on a partial postcranial skeleton collected from the Lower Cretaceous Napai Formation of Guangxi, China, we erect a new sauropod taxon, Fusuisaurus zhaoi gen. et sp. nov. The holotype specimen consists of the left ilium, left pubis, anterior caudals, most of the dorsal ribs and distal end of the left femur. Fusuisaurus zhaoi is diagnosed by a unique combination of character states among the known sauropods. It displays several synapomorphies of Titanosauriformes but lacks many derived features seen in other titanosauriforms, suggesting that the new taxon represents the basalmost known titanosauriform and providing new evidence that Titanosauriformes originated from Asia. A size comparison suggests that Fusuisaurus zhaoi is among the largest Early Cretaceous sauropods, providing an important addition to the Early Cretaceous Chinese sauropod diversity.
基金Project supported by the National Natural Science Foundation of China(No.11772089)the Fundamental Research Funds for the Central Universities of China(Nos.N170308028 and N170306004)+1 种基金the Program for the Innovative Talents of Higher Learning Institutions of Liaoning of China(No.LR2017035)the Liaoning Revitalization Talents Program of China(No.XLYC1807008)
文摘A rotating pre-twisted and inclined cantilever beam model (RPICBM) with the flapwise-chordwise-axial-torsional coupling is established with the Hamilton principle and the finite element (FE) method. The effectiveness of the model is verified via comparisons with the literatures and the FE models in ANSYS. The effects of the setting and pre-twisted angles on the dynamic responses of the RPICBM are analyzed. The results show that:(i) the increase in the setting or pre-twisted angle results in the increases in the first-order flapwise and torsional frequencies while the decrease in the first-order chordwise frequency under rotating conditions;(ii) a positive/negative setting angle leads to a positive/negative constant component, while a positive/negative pre-twisted angle leads to a negative/positive constant component;(iii) when the rotation speed is non-zero, the pre-twisted angle or non-zero setting angle will result in the coupled flapwise-chordwiseaxial- torsional vibration of the RPICBM under axial base excitation.
基金supported by the National Natural Science Foundation of China(61072120)
文摘This paper deals with the blind separation of nonstation-ary sources and direction-of-arrival （DOA） estimation in the under-determined case, when there are more sources than sensors. We assume the sources to be time-frequency （TF） disjoint to a certain extent. In particular, the number of sources presented at any TF neighborhood is strictly less than that of sensors. We can identify the real number of active sources and achieve separation in any TF neighborhood by the sparse representation method. Compared with the subspace-based algorithm under the same sparseness assumption, which suffers from the extra noise effect since it can-not estimate the true number of active sources, the proposed algorithm can estimate the number of active sources and their cor-responding TF values in any TF neighborhood simultaneously. An-other contribution of this paper is a new estimation procedure for the DOA of sources in the underdetermined case, which combines the TF sparseness of sources and the clustering technique. Sim-ulation results demonstrate the validity and high performance of the proposed algorithm in both blind source separation （BSS） and DOA estimation.
基金This study was supported by the National Natural Science Foundation of China (Grant Nos.51778475 and 41472248).
文摘Frost heave experiments on saturated sandstone and tuff with an open crack are conducted under uniform and unidirectional freezing conditions.Frost heave of crack in sandstone with high permeability is more significant under uniform freezing condition than that under unidirectional freezing condition.However,frost heave of crack in tuff with low permeability is more significant under unidirectional freezing condition.To illustrate the reasons for this phenomenon,a numerical model on the freezing processes of saturated rock with an open crack considering the latent heat of pore water and water in crack is proposed and confirmed to be reliable.Numerical results show that a frozen shell that blocks the migration of water in crack to rock develops first in the outer part of the rock before the freezing of water in crack under unifonn freezing condition.However,the migration path of water in crack to the unfrozen rock under freezing front exists under unidirectional freezing condition.The freezing process and permeability of rock together determine the migration of water in crack and lead to the different frost heave modes of crack for various permeable rocks under different freezing conditions.The frost heave modes of crack in rock with low or high permeability are similar under uniform freezing condition because water migration is blocked by a frozen shell and is irrelevant to rock permeability.For high permeability rock,the frost heave of crack will be weakened due to water migration under unidirectional freezing condition;however,the frost heave of crack would be more significant for low permeability rock because water migration is blocked under unidirectional freezing condition.Therefore,the freezing condition and rock permeability determine the frost heave of rock with crack together,and this should be concerned in cold regions engineering applications.
文摘We study the determinants of China ＇s bilateral local currency swap lines that were established following the recent global finance crisis. It is found that economic factors, political considerations and institutional characteristics, including trade intensity, economic size, strategic partnership, free trade agreements, corruption and stability, affect the decision to sign a swap line agreement. Once a swap line agreement decision is made, the size of the swap line is then mainly affected by trade intensity, economic size and the presence of a free trade agreement. The results are quite robust with respect to the choices of the Heckman two-stage framework or the proportional hazard model. The gravity effect captured by distances between China and its counterparts, if present, is mainly observed during the early part of the sample period under consideration.
文摘Achyranthes bidentata and Achyranthes aspera are saponin and steroid rich medicinal plants, used extensively for therapeutic treatments in Traditional Chinese Medicine(TCM) and Ayurveda. A. bidentata is reported to be one of the rare and extensively exploited medicinal plant species that face the issue of being endangered.Finding qualitative substitute with identical phyto-constituents contributing to similar composition and pharmacological benefits will help in reducing the burden of exploitation of the natural habitats of such plants.In the present study, a comparative metabolite analysis of the whole drug and specific tissues isolated by laser micro-dissection(LMD) was carried out for both the selected species, by use of ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry(UHPLC-QTOF MS). The results of the study indicate that the cortex and the medullary ray tissues are rich in their content of steroidal and saponin constituents such as(25 S)-inokosterone-20,22-acetonide, ginsenoside Ro, bidentatoside II and achyranthoside B.Metabolite profiling of the whole tissues of both the species indicates presence of identical constituents. Thus,it is inferred that A. bidentata and A. aspera can be used as qualitative substitutes for each other.
