The horizontal structure of mangrove forests is an important characteristic that reflects a significant signal for coupling between mangroves and external drivers.While the loss and gain of mangroves has received much...The horizontal structure of mangrove forests is an important characteristic that reflects a significant signal for coupling between mangroves and external drivers.While the loss and gain of mangroves has received much attention,little information about how the horizontal structure of mangrove forests develops from the seedling stage to maturity has been presented.Here,remote sensing images taken over approximately 15 years,UVA images,nutrient elements,sediments,and Aegiceras corniculatum vegetation parameters of the ecological quadrats along the Nanliu Delta,the largest delta of the northern Beibu Gulf in China,are analyzed to reveal changes in the horizontal structure of mangroves and their associated driving factors.The results show that both discrete structures and agglomerated structures can often be found in A.corniculatum seedlings and saplings.However,the combination of seedlings growing into maturity and new seedlings filling in available gaps causes the discrete structure of A.corniculatum to gradually vanish and the agglomerate structure to become stable.The aggregated structure of seedlings,compared to the discrete structure,can enhance the elevation beneath mangroves by trapping significantly more sediments,providing available spaces and conditions for seedlings to continue growing.Furthermore,by catching fine sediments with enriched nutrients,the survival rate of A.corniculatum seedlings in the agglomerated structure can be much higher than that in the discrete structure.Our results highlight the significance of the agglomeration of A.corniculatum,which can be beneficial to coastal mangrove restoration and management.展开更多
In this paper, we report new whole-rock geochemical and zircon U–Pb data for monzogranites in the NE Xing'an block. These data constrained the petrogenesis of C type(high Sr/Y) adakitic rocks and showed the spati...In this paper, we report new whole-rock geochemical and zircon U–Pb data for monzogranites in the NE Xing'an block. These data constrained the petrogenesis of C type(high Sr/Y) adakitic rocks and showed the spatial extent of the influence of the Mongol-Okhostsk ocean tectonic regime and the collision between the Jiamusi Massif and Songliao Terrane. New zircon laser-ablation inductivity coupled plasma mass spectrometry(LA-ICP-MS) U–Pb data indicated that the monzogranites in the studied area were emplaced in the Early Jurassic(~180 Ma). These rocks were characterized by unusally high SiO_2(C67.49), and Sr(461–759 ppm), but strikingly low Y(4.63–8.06 ppm) and HREE(P HREE = 3.83–6.49 ppm, Yb = 0.5–0.77 ppm)contents, with therefore high Sr/Y(67.2–119) and(La/Yb)N(29.7–41.5) ratios, showing the geochemical characteristics of C type adakitic granite. The data displayed negligible Eu anomalies(Eu/Eu~ = 0.77–1.08), LREE-enriched and pronounced negative Nb and Ta anomalies. The C-typeadakites in the studied area were most likely derived from the partial melting of a thickened lower continental curst. The magma source is most likely dominated by amphibolites and garnet amphibolites. In combination with previously-reported data from igneous rocks from the Mesozoic in NE China, we conclude that the Xing'an block was influenced by the Mongol-Okhotsk subduction tectonic system, and experiences compressive settings from the amalgamation of the Jiamusi block in the east of the CAOB.展开更多
Fruit lignification is of significant economic importance because it affects the quality of fruit and the production of seed oil.The specified lignification pattern in Camellia chekiangoleosa fruits plays critical rol...Fruit lignification is of significant economic importance because it affects the quality of fruit and the production of seed oil.The specified lignification pattern in Camellia chekiangoleosa fruits plays critical roles in its seed oil yield,but little is known about how this lignification process is regulated.Here,we report on a comprehensive tissue-specific transcriptomics analysis conducted for C.chekiangoleosa fruit.By mining the differentially expressed genes,we found that lignin biosynthesis and transcriptional regulation pathways were significantly enriched in the lignified tissues.The homolog of NST-like transcription factor,CcNST1,was highly expressed in lignified seed coat and endocarp tissues;transgenic analyses of CcNST1 in Arabidopsis and hybrid poplar revealed the enhanced lignification levels of various tissues.Gene expression analysis of the transgenic lines uncovered potential downstream genes involved in the regulation of lignin biosynthesis.This work provides a valuable gene expression resource and identified the pivotal role of CcNST1 in regulating the lignin biosynthesis underlying fruit lignification.展开更多
Late Paleozoic pillow basalts are well preserved in the Youjiang Basin of SW China.In this study,we conducted geochemical and Sr-Nd isotopic study on the Late Devonian and Late Carboniferous basalts in Napo area,Youji...Late Paleozoic pillow basalts are well preserved in the Youjiang Basin of SW China.In this study,we conducted geochemical and Sr-Nd isotopic study on the Late Devonian and Late Carboniferous basalts in Napo area,Youjiang Basin.The analyzed samples comprise moderate SiO2,TiO2,Mg#,and REE contents,with slightly positive or negative Eu anomalies,similar to the chemical nature of OIB(Oceanic island basalt).All basalts show low(^(143)Nd/^(144)Nd)iand(^(87)Sr/^(86)Sr)ivalues,close to EMI-type(I-type Enriched Mantle)magma source.Late Carboniferous basalts display higher(^(87)Sr/^(86)Sr)i,Nb/Th,and lowerε_(Nd)(t),Zr/Nb values than those of the Late Devonian basalts,implying progressively decreased enrichment components in the magma source processes.Such evolution trend reflects a continuous lithospheric thinning event,supporting a progressive rifting setting of the Youjiang Basin along the southwestern margin of the Yangtze Block in Late Paleozoic.Combined with regional geological background,the Youjiang Basin is viewed as a continental rift basin related to the opening of the Paleo-Tethys Ocean in Late Devonian and became a passive continental margin basin in Carboniferous.The Paleo-Tethys branch ocean probably extended further to the southern Youjiang Basin,likely corresponding to the Song Ma suture zone.展开更多
By imitating the body structure and movement mode of the crab in nature,a novel stick–slip piezo-driven positioning platform was proposed by employing the bionic flexible hinge mechanism with a symmetrical structure ...By imitating the body structure and movement mode of the crab in nature,a novel stick–slip piezo-driven positioning platform was proposed by employing the bionic flexible hinge mechanism with a symmetrical structure and two piezoelectric stacks.The structural design and bionic motion principle were discussed,followed by analyzing the feasibility,safety,and output magnification ratio of the bionic flexible hinge mechanism via the stiffness matrix method and finite element simulation.To investigate the output performances of the positioning platform,a prototype was fabricated and an experiment system was established.Stepping characteristics of the positioning platform under various driving voltages were characterized,and the results indicated that the positioning platform could move steadily under various driving voltages.Within 1 s,the differences between the forward and reverse output displacement were less than 3%under different driving frequencies,proving the high bidirectional motion symmetry.The maximum driving speed of 5.44 mm/s was obtained under the driving voltage of 120 V and driving frequency of 5 Hz.In addition,the carrying load capacity of the positioning platform was tested by standard weights,and the results showed that when the carrying load reached 10 N,the driving speed could still reach 60μm/s.展开更多
Transverse stimulated Raman scattering(TSRS)in potassium dihydrogen phosphate(KDP)and deuterated potassium dihydrogen phosphate(DKDP)plates for large-aperture,inertial confinement fusion(ICF)-class laser systems is a ...Transverse stimulated Raman scattering(TSRS)in potassium dihydrogen phosphate(KDP)and deuterated potassium dihydrogen phosphate(DKDP)plates for large-aperture,inertial confinement fusion(ICF)-class laser systems is a well-recognized limitation giving rise to parasitic energy conversion and laser-induced damage.The onset of TSRS is manifested in plates exposed to the ultraviolet section of the beam.TSRS amplification is a coherent process that grows exponentially and is distributed nonuniformly in the crystal and at the crystal surfaces.To understand the growth and spatial distribution of TSRS energy in various configurations,a modeling approach has been developed to simulate the operational conditions relevant to ICF-class laser systems.Specific aspects explored in this work include(i)the behavior of TSRS in large-aperture crystal plates suitable for third-harmonic generation and use as wave plates for polarization control in current-generation ICF-class laser system configurations;(ii)methods,and their limitations,of TSRS suppression and(iii)optimal geometries to guide future designs.展开更多
Knowledge-based modeling is a trend in complex system modeling technology. To extract the process knowledge from an information system, an approach of knowledge modeling based on interval-valued fuzzy rough set is pre...Knowledge-based modeling is a trend in complex system modeling technology. To extract the process knowledge from an information system, an approach of knowledge modeling based on interval-valued fuzzy rough set is presented in this paper, in which attribute reduction is a key to obtain the simplified knowledge model. Through defining dependency and inclusion functions, algorithms for attribute reduction and rule extraction are obtained. The approximation inference plays an important role in the development of the fuzzy system. To improve the inference mechanism, we provide a method of similaritybased inference in an interval-valued fuzzy environment. Combining the conventional compositional rule of inference with similarity based approximate reasoning, an inference result is deduced via rule translation, similarity matching, relation modification, and projection operation. This approach is applied to the problem of predicting welding distortion in marine structures, and the experimental results validate the effectiveness of the proposed methods of knowledge modeling and similarity-based inference.展开更多
In this paper,a new numerical algorithm for solving the time fractional Fokker-Planck equation is proposed.The analysis of local truncation error and the stability of this method are investigated.Theoretical analysis ...In this paper,a new numerical algorithm for solving the time fractional Fokker-Planck equation is proposed.The analysis of local truncation error and the stability of this method are investigated.Theoretical analysis and numerical experiments show that the proposed method has higher order of accuracy for solving the time fractional Fokker-Planck equation.展开更多
基金The National Natural Science Key Foundation of China under contract No.41930537the Key Research Base of Humanities and Social Sciences in Guangxi Universities“Beibu Gulf Ocean Development Research Center”under contract No.10BHZKY2110+1 种基金the Key Research and Development Plan of Guangxi under contract No.Guike AB21076016the Marine Science Program for Guangxi First-Class Discipline,Beibu Gulf University.
文摘The horizontal structure of mangrove forests is an important characteristic that reflects a significant signal for coupling between mangroves and external drivers.While the loss and gain of mangroves has received much attention,little information about how the horizontal structure of mangrove forests develops from the seedling stage to maturity has been presented.Here,remote sensing images taken over approximately 15 years,UVA images,nutrient elements,sediments,and Aegiceras corniculatum vegetation parameters of the ecological quadrats along the Nanliu Delta,the largest delta of the northern Beibu Gulf in China,are analyzed to reveal changes in the horizontal structure of mangroves and their associated driving factors.The results show that both discrete structures and agglomerated structures can often be found in A.corniculatum seedlings and saplings.However,the combination of seedlings growing into maturity and new seedlings filling in available gaps causes the discrete structure of A.corniculatum to gradually vanish and the agglomerate structure to become stable.The aggregated structure of seedlings,compared to the discrete structure,can enhance the elevation beneath mangroves by trapping significantly more sediments,providing available spaces and conditions for seedlings to continue growing.Furthermore,by catching fine sediments with enriched nutrients,the survival rate of A.corniculatum seedlings in the agglomerated structure can be much higher than that in the discrete structure.Our results highlight the significance of the agglomeration of A.corniculatum,which can be beneficial to coastal mangrove restoration and management.
基金supported by the regional geology and mineralization research program of Heilongjiang province (HLJKD201417)
文摘In this paper, we report new whole-rock geochemical and zircon U–Pb data for monzogranites in the NE Xing'an block. These data constrained the petrogenesis of C type(high Sr/Y) adakitic rocks and showed the spatial extent of the influence of the Mongol-Okhostsk ocean tectonic regime and the collision between the Jiamusi Massif and Songliao Terrane. New zircon laser-ablation inductivity coupled plasma mass spectrometry(LA-ICP-MS) U–Pb data indicated that the monzogranites in the studied area were emplaced in the Early Jurassic(~180 Ma). These rocks were characterized by unusally high SiO_2(C67.49), and Sr(461–759 ppm), but strikingly low Y(4.63–8.06 ppm) and HREE(P HREE = 3.83–6.49 ppm, Yb = 0.5–0.77 ppm)contents, with therefore high Sr/Y(67.2–119) and(La/Yb)N(29.7–41.5) ratios, showing the geochemical characteristics of C type adakitic granite. The data displayed negligible Eu anomalies(Eu/Eu~ = 0.77–1.08), LREE-enriched and pronounced negative Nb and Ta anomalies. The C-typeadakites in the studied area were most likely derived from the partial melting of a thickened lower continental curst. The magma source is most likely dominated by amphibolites and garnet amphibolites. In combination with previously-reported data from igneous rocks from the Mesozoic in NE China, we conclude that the Xing'an block was influenced by the Mongol-Okhotsk subduction tectonic system, and experiences compressive settings from the amalgamation of the Jiamusi block in the east of the CAOB.
基金supported by Nonprofit Research Projects(CAFYBB2021QD001)of Chinese Academy of ForestryNational Key R&D Program of China(2019YFD1001602)。
文摘Fruit lignification is of significant economic importance because it affects the quality of fruit and the production of seed oil.The specified lignification pattern in Camellia chekiangoleosa fruits plays critical roles in its seed oil yield,but little is known about how this lignification process is regulated.Here,we report on a comprehensive tissue-specific transcriptomics analysis conducted for C.chekiangoleosa fruit.By mining the differentially expressed genes,we found that lignin biosynthesis and transcriptional regulation pathways were significantly enriched in the lignified tissues.The homolog of NST-like transcription factor,CcNST1,was highly expressed in lignified seed coat and endocarp tissues;transgenic analyses of CcNST1 in Arabidopsis and hybrid poplar revealed the enhanced lignification levels of various tissues.Gene expression analysis of the transgenic lines uncovered potential downstream genes involved in the regulation of lignin biosynthesis.This work provides a valuable gene expression resource and identified the pivotal role of CcNST1 in regulating the lignin biosynthesis underlying fruit lignification.
基金supported by the National Natural Science Foundation of China(No.41672106)China Postdoctoral Science Foundation(No.2020M672087)。
文摘Late Paleozoic pillow basalts are well preserved in the Youjiang Basin of SW China.In this study,we conducted geochemical and Sr-Nd isotopic study on the Late Devonian and Late Carboniferous basalts in Napo area,Youjiang Basin.The analyzed samples comprise moderate SiO2,TiO2,Mg#,and REE contents,with slightly positive or negative Eu anomalies,similar to the chemical nature of OIB(Oceanic island basalt).All basalts show low(^(143)Nd/^(144)Nd)iand(^(87)Sr/^(86)Sr)ivalues,close to EMI-type(I-type Enriched Mantle)magma source.Late Carboniferous basalts display higher(^(87)Sr/^(86)Sr)i,Nb/Th,and lowerε_(Nd)(t),Zr/Nb values than those of the Late Devonian basalts,implying progressively decreased enrichment components in the magma source processes.Such evolution trend reflects a continuous lithospheric thinning event,supporting a progressive rifting setting of the Youjiang Basin along the southwestern margin of the Yangtze Block in Late Paleozoic.Combined with regional geological background,the Youjiang Basin is viewed as a continental rift basin related to the opening of the Paleo-Tethys Ocean in Late Devonian and became a passive continental margin basin in Carboniferous.The Paleo-Tethys branch ocean probably extended further to the southern Youjiang Basin,likely corresponding to the Song Ma suture zone.
基金This work was supported by the National Natural Science Foundation of China(Grant No.52075221)the Research Foundation of Education Department of Jilin Province,China(Grant No.JJKH20231153KJ)the Fundamental Research Funds for the Central Universities(2019-2023).
文摘By imitating the body structure and movement mode of the crab in nature,a novel stick–slip piezo-driven positioning platform was proposed by employing the bionic flexible hinge mechanism with a symmetrical structure and two piezoelectric stacks.The structural design and bionic motion principle were discussed,followed by analyzing the feasibility,safety,and output magnification ratio of the bionic flexible hinge mechanism via the stiffness matrix method and finite element simulation.To investigate the output performances of the positioning platform,a prototype was fabricated and an experiment system was established.Stepping characteristics of the positioning platform under various driving voltages were characterized,and the results indicated that the positioning platform could move steadily under various driving voltages.Within 1 s,the differences between the forward and reverse output displacement were less than 3%under different driving frequencies,proving the high bidirectional motion symmetry.The maximum driving speed of 5.44 mm/s was obtained under the driving voltage of 120 V and driving frequency of 5 Hz.In addition,the carrying load capacity of the positioning platform was tested by standard weights,and the results showed that when the carrying load reached 10 N,the driving speed could still reach 60μm/s.
基金This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0003856,the University of Rochester and the New York State Energy Research and Development Authority。
文摘Transverse stimulated Raman scattering(TSRS)in potassium dihydrogen phosphate(KDP)and deuterated potassium dihydrogen phosphate(DKDP)plates for large-aperture,inertial confinement fusion(ICF)-class laser systems is a well-recognized limitation giving rise to parasitic energy conversion and laser-induced damage.The onset of TSRS is manifested in plates exposed to the ultraviolet section of the beam.TSRS amplification is a coherent process that grows exponentially and is distributed nonuniformly in the crystal and at the crystal surfaces.To understand the growth and spatial distribution of TSRS energy in various configurations,a modeling approach has been developed to simulate the operational conditions relevant to ICF-class laser systems.Specific aspects explored in this work include(i)the behavior of TSRS in large-aperture crystal plates suitable for third-harmonic generation and use as wave plates for polarization control in current-generation ICF-class laser system configurations;(ii)methods,and their limitations,of TSRS suppression and(iii)optimal geometries to guide future designs.
基金supported by 2013 Comprehensive Reform Pilot of Marine Engineering Specialty(No.ZG0434)
文摘Knowledge-based modeling is a trend in complex system modeling technology. To extract the process knowledge from an information system, an approach of knowledge modeling based on interval-valued fuzzy rough set is presented in this paper, in which attribute reduction is a key to obtain the simplified knowledge model. Through defining dependency and inclusion functions, algorithms for attribute reduction and rule extraction are obtained. The approximation inference plays an important role in the development of the fuzzy system. To improve the inference mechanism, we provide a method of similaritybased inference in an interval-valued fuzzy environment. Combining the conventional compositional rule of inference with similarity based approximate reasoning, an inference result is deduced via rule translation, similarity matching, relation modification, and projection operation. This approach is applied to the problem of predicting welding distortion in marine structures, and the experimental results validate the effectiveness of the proposed methods of knowledge modeling and similarity-based inference.
基金This work is supported by projects from Hunan Provincial Science and Technology Department(No.2010JT4054)the National Natural Science Foundation of China(No.11171282 and No.10971175).The authors wish to express their sincere thanks for the reviewer’s constructive suggestions.
文摘In this paper,a new numerical algorithm for solving the time fractional Fokker-Planck equation is proposed.The analysis of local truncation error and the stability of this method are investigated.Theoretical analysis and numerical experiments show that the proposed method has higher order of accuracy for solving the time fractional Fokker-Planck equation.
