The experiments of single factor evaluation method, principal component analysis and voronoi area weighting factor method on the sample data of Liangzi Lake in October 2012 combined with the national surface water env...The experiments of single factor evaluation method, principal component analysis and voronoi area weighting factor method on the sample data of Liangzi Lake in October 2012 combined with the national surface water environment quality standards can get the map of comprehensive water quality distribution by Kriging interpolation. The analysis shows, the grades of comprehensive water quality gained by three methods are all only class III or class IV, and the quality of water is different from east and west that the water quality of east is better. However, the percent of IV class water is higher in the result of single factor evaluation method means class IV is the main grade of water quality. The result of principal component analysis shows the percent of class Ⅲ water is higher than other classes. The result of voronoi area weighting factor method shows the percent of IV class is higher than other classes. COD<sub>Mn</sub> is the main factor that influences the method of singal factor evaluation and reduces the grade of water quality overall. The effect of single factor is reduced by principal component analysis, and the analysis on water quality is more accurate. The voronoi area weighing factor method reduces the effect of single factor and extends the content, can make a comprehensive evaluation on water quality.展开更多
Development and utilization of hydrogen energy is an effective way to achieve carbon neutrality,only hydrogen production through electrolytic water splitting meets the goal of zero carbon emission.To facilitate the la...Development and utilization of hydrogen energy is an effective way to achieve carbon neutrality,only hydrogen production through electrolytic water splitting meets the goal of zero carbon emission.To facilitate the large-scale commercialization of water splitting devices,the development of highly efficient and low-cost catalysts to reduce the energy consumption is essential.MoS_(2)has been regarded as a promising electrocatalyst to replace platinum in hydrogen evolution reaction due to its low price and unique 2D layered structure.However,the poor conductivity and inert basal planes of MoS_(2)limited its wide-spread application.Recently,researches have demonstrated that the conductivity and active sites of MoS_(2)can be improved by heteroatoms doping or constructing of heterogeneous structures.In this review,the recent progress of Mo-based catalysts are summarized centered on MoS_(2)based on interface engineering and anion engineering,including MoS_(2)–MoO_(2),MoS_(2)–Mo_(2)C,MoS_(2)–MoN_(x),MoS_(2)–MoP,and MoS_(2)–MoSe_(2).The preparation method,structure,and performance of the catalysts are introduced and the possible mechanism behind the improved catalytic activity are revealed to give readers an overall comprehension on the progress of the Mo-based electrocatalysts for hydrogen evolution reaction.In addition,an outlook on future opportunities and development directions of Mo-based catalysts are proposed to facilitate the development of Mo-based catalysts for hydrogen production.展开更多
Bacterial blight, caused by Xanthomonas oryzae pv. oryzae(Xoo), is one of the most destructive diseases of rice(Oryza sativa L.) worldwide. The type III secretion system(T3SS) of Xoo, encoded by the hrp(hypersensitive...Bacterial blight, caused by Xanthomonas oryzae pv. oryzae(Xoo), is one of the most destructive diseases of rice(Oryza sativa L.) worldwide. The type III secretion system(T3SS) of Xoo, encoded by the hrp(hypersensitive response and pathogenicity) genes, plays critical roles in conferring pathogenicity in host rice and triggering a hypersensitive response(HR) in non-host plants. To investigate the major genes conferring the pathogenicity and avirulence of Xoo, we previously constructed a random Tn5-insertion mutant library of Xoo strain PXO99A. We report here the isolation and characterization of a Tn5-insertion mutant PXM69. Tn5-insertion mutants were screened on indica rice JG30, which is highly susceptible to PXO99A, by leaf-cutting inoculation.Four mutants with reduced virulence were obtained after two rounds of screening. Among them, the mutant PXM69 had completely lost virulence to the rice host and ability to elicit HR in non-host tobacco. Southern blotting analysis showed a single copy of a Tn5-insertion in the genome of PXM69. PCR walking and sequencing analysis revealed that the Tn5 transposon was inserted at nucleotide position 70,192–70,201 in the genome of PXO99A, disrupting the type III hrc(hrp-conserved) gene hrcQ, the first gene in the D operon of the hrp cluster in Xoo. To confirm the relationship between the Tn5-insertion and the avirulence phenotype of PXM69, we used the marker exchange mutagenesis to create a PXO99Amutant, ΔhrcQ::KAN, in which the hrcQ was disrupted by a kanamycin-encoding gene cassette at the same site as that of the Tn5-insertion. ΔhrcQ::KAN showed the same phenotype as mutant PXM69. Reintroduction of the wild-type hrcQ gene partially complemented the pathogenic function of PXM69. RT-PCR and cellulase secretion assays showed that the Tn5-disruption of hrcQ did not affect transcription of downstream genes in the D operon and function of the type II secretion system. Our results provide new insights into the pathogenic functions of clustered hrp genes in Xoo.展开更多
Deep-ultraviolet(deep-UV)nonlinear optical(NLO)crystals are of current interest because they play an indis-pensable role in modern scientific equipment.Searching these crystals was traditionally limited toπ-conjugate...Deep-ultraviolet(deep-UV)nonlinear optical(NLO)crystals are of current interest because they play an indis-pensable role in modern scientific equipment.Searching these crystals was traditionally limited toπ-conjugated systems,such as borates and carbonates.In 2019,our group reported two non-π-conjugated sulfates as new sources of deep-UV NLO crystals for the first time.In this mini review,we provide a comprehensive overview of the recent development of non-π-conjugated NLO sulfates with deep-UV absorption edge in aspect of synthesis methods,crystal structures,thermal stability,and optical performance.Besides,we conclude the crucial structure-property relationships,and further give some prospects for exploring non-π-conjugated NLO sulfates with deep-UV absorption edge with high thermal stability,enhanced second-order NLO effects,birefringence,etc.We believe that this mini review will not only facilitate researchers to design superior non-π-conjugated NLO sulfates with deep-UV absorption edge but also shed useful insights on the explorations of other non-π-conjugated deep-UV NLO crystal systems.展开更多
High-performance bi-functional materials are in urgent demand for the next-generation integrated optical devices.In this work,we successfully synthesized the first tricyanomelaminate with bi-functional optical respons...High-performance bi-functional materials are in urgent demand for the next-generation integrated optical devices.In this work,we successfully synthesized the first tricyanomelaminate with bi-functional optical responses,namely Cs_(3)C_(6)N_(9)•H_(2)O(I),from its analogue Na_(3)C_(6)N_(9)•3H_(2)O by a facile ion exchange method.In contrast to Na_(3)C_(6)N_(9)•3H_(2)O,I realizes an optimal arrangement of𝜋π-conjugated(C_(6)N_(9))3−anion groups in its crystal structure.As a result,the second-order nonlinear optical(NLO)response is greatly enhanced from nearly zero of Na_(3)C_(6)N_(9)•3H_(2)O to∼9.8×KH_(2)PO_(4)of I.Furthermore,I exhibits a giant linear optical anisotropic response(i.e.birefringence)of 0.52 at the wavelength of 550 nm.Both responses are almost the largest among the inorganic compounds ofπ-conjugated rings,which indicates that I has great potential as a bi-functional optical crystal.Structural and theoretical analyses reveal the microscopic origin of excellent optical properties.This work would attract a lot of interest to the persistently neglected potential of tricyanomelaminates as linear optical and NLO crystals.展开更多
Solidification experiments were performed with Lead-Aluminum immiscible alloy under the effect of composite electric and magnetic fields(CEMFs).The results demonstrate that CEMFs not only decrease the size of minority...Solidification experiments were performed with Lead-Aluminum immiscible alloy under the effect of composite electric and magnetic fields(CEMFs).The results demonstrate that CEMFs not only decrease the size of minority phase particles(MPPs)but also promote a more uniform distribution of the MPPs.A theoretical model was built to describe the microstructure evolution during cooling the immiscible alloy.The solidification process of Pb-0.4 wt.%Al alloy under the effect of the CEMFs was simulated.The numerical results are well consistent with the experimental data.These results demonstrate that CEMFs affect the solidification process through changing melt convection and the nucleation behavior of minority phase droplets(MPDs).On one hand,the CEMFs can inhibit the convection and lead to the homogeneous distribution of MPPs along the radial direction of the sample.On the other hand,the CEMFs can increase the nucleation driving force for the MPDs,which decreases the average radius of MPDs and boosts the formation of dispersed solidification structures.This research indicates that the application of CEMFs is a promising strategy for controlling the microstructure of immiscible alloys.展开更多
1.Text 2D van der Waals materials possess intriguing features[1],especially optically,such as high nonlinear optical responses[2],broadband spectral response[3],and accessible exciton effects[4].Unlike conventional 2D...1.Text 2D van der Waals materials possess intriguing features[1],especially optically,such as high nonlinear optical responses[2],broadband spectral response[3],and accessible exciton effects[4].Unlike conventional 2D materials with in-plane isotropy,such as graphene and M0S_(2),2D van der Waals materials with in-plane anisotropic possess in-plane low symmetry structure,inducing the in-plane anisotropic physical properties.Meanwhile,they can be easily moved to various substrates without lattice-matching problems.展开更多
There is a pressing demand for the development of novel birefringent crystals tailored for compact optical components,especially for crystals exhibiting large birefringence across a range of temperatures.This has comm...There is a pressing demand for the development of novel birefringent crystals tailored for compact optical components,especially for crystals exhibiting large birefringence across a range of temperatures.This has commonly been achieved by introducing various deformable groups with high polarizability anisotropy.In this study,we combined both rigid and deformable groups to synthesise a new birefringent crystal,Al_(2)Te_(2)MoO_(10),which demonstrates an exceptional birefringence value of 0.29@550 nm at room temperature.Not only is this higher birefringence than that of commercial crystals,but Al_(2)Te_(2)MoO_(10)exhibits excellent birefringence stability over a wide temperature range,from 123 to 503 K.In addition,the first-principles theory calculations and structural analyses suggest that although the rigid AlO_(6)groups do not make much contribution to the prominent birefringence,they nonetheless played a role in maintaining the structural anisotropy at elevated temperatures.Based on these findings,this paper proposes a novel structural design strategy to complement conventional approaches for developing optimal birefringent crystals under various environmental conditions.展开更多
Nonlinear optical(NLO)switchable materials have attracted intense attention because of their promising applications in optoelectronic devices.However,previous studies are mainly limited to molecular-based compounds th...Nonlinear optical(NLO)switchable materials have attracted intense attention because of their promising applications in optoelectronic devices.However,previous studies are mainly limited to molecular-based compounds that usually exhibit narrow bandgaps.Here,we report all-inorganic Li_(9)Na_(3)Rb_(2)(SO_(4))_(7) as an ultrawide-bandgap NLO switchable material.展开更多
Single-atom catalysts with precise structure and tunable coordination nature provide opportunities for developing novel catalytic centers and understanding reaction mechanisms.Herein,hollow Co_(9)S_(8)polyhedrons with...Single-atom catalysts with precise structure and tunable coordination nature provide opportunities for developing novel catalytic centers and understanding reaction mechanisms.Herein,hollow Co_(9)S_(8)polyhedrons with lattice-confined Ru single atoms(Ru-Co_(9)S_(8))are fabricated.Aberration-corrected scanning transmission electron microscopy and X-ray absorption spectroscopy verify the isolated Ru atoms are confined in Co_(9)S_(8)to form Co-S-Ru catalytic centers.Theoretical calculations indicate that the oxygen evolution reaction(OER)and oxygen reduction reaction(ORR)energy barriers are extensively reduced,the d-band center of Co_(9)S_(8)downshifts from the Fermi level,therefore boosting the desorption of O-containing intermediates.Consequently,the Ru-Co_(9)S_(8)exhibits an ultralow overpotential of 163 mV at 10 mA·cm^(−2)for OER and could catalyze a rechargeable Zn-air battery with a high-power density of 92.0 mW·cm^(−2).This work provides a promising approach for designing novel bifunctional catalytic active centers for energy conversion.展开更多
The majority of plant disease resistance （R） genes encode proteins that share common structural features. However, the transcription activator-like effector （TALE）-associated executor type R genes show no consider...The majority of plant disease resistance （R） genes encode proteins that share common structural features. However, the transcription activator-like effector （TALE）-associated executor type R genes show no considerable sequence homology to any known R genes. We adopted a map-based cloning approach and TALE-based technology to isolate and characterize Xa23, a new executor R gene derived from wild rice （Oryza rufipogon） that confers an extremely broad spectrum of resistance to bacterial blight caused by Xanthomonas oryzae pv. oryzae （Xoo）. Xa23 encodes a 113 amino acid protein that shares 50% identity with the known executor R protein XA10. The predicted transmembrane helices in XA23 also overlap with those of XA10. Unlike XalO, however, Xa23 transcription is specifically activated by AvrXa23, a TALE present in all examined Xoo field isolates. Moreover, the susceptible xa23 allele has an identical open reading frame of Xa23 but differs in promoter region by lacking the TALE binding element （EBE） for AvrXa23. XA23 can trigger a strong hypersensitive response in rice, tobacco, and tomato. Our results provide the first evidence that plant genomes have an executor R gene family of which members execute their function and spectrum of disease resistance by recognizing the cognate TALEs in the pathogen.展开更多
Designing a highly efficient non-precious based oxygen reduction reaction(ORR)electrocatalyst is critical for the commercialization of various sustainable energy storage and conversion devices such as metal-air batter...Designing a highly efficient non-precious based oxygen reduction reaction(ORR)electrocatalyst is critical for the commercialization of various sustainable energy storage and conversion devices such as metal-air batteries and fuel cells.Herein,we report a convenient strategy to synthesis Fe3O4 embedded in N doped hollow carbon sphere(NHCS)for ORR.What's interesting is that the carbon microsphere is composed of two-dimensional(2D)nanoplate that could provide more exposed active sites.The usage of solid ZnO nanowires as zinc source is crucial to obtain this structure.The Fe3O4@NHCS-2 exhibits better catalytic activity and durability than the commercial PtC catalyst.Moreover,it further displays high-performance of Zn-air batteries as a cathode electrocatalyst with a high-power density of 133 mW·cm^-2 and high specific capacity of 701 mA·h·g^-1.The special hollow structure composed 2D nanoplate,high surface area,as well as synergistic effect between the high active Fe3O4 nanoparticles and N-doped matrix endows this outstanding catalytic activity.The work presented here can be easily extended to prepare metal compounds decorated carbon nanomaterials with special structure for a broad range of energy storage and conversion devices.展开更多
Conventional wisdom says that nonpolar structures do not favorably produce strong second-harmonic generation(SHG)responses since the polarization in their microscopic functional groups are counteracted.Herein,we repor...Conventional wisdom says that nonpolar structures do not favorably produce strong second-harmonic generation(SHG)responses since the polarization in their microscopic functional groups are counteracted.Herein,we report the first nonlinear optical thiosulfate,Na_(10)Cd(NO_(3))_(4)(SO_(3)S)_(4),which crystallizes in a nonpolar space group of P−4.However,this thiosulfate exhibits a strong SHG response of about 4.2 times that of the benchmark KH2PO4,which is larger than those of polar sulfates.According to first-principles calculations and a flexible dipole model,the SHG enhancement is mainly ascribed to the larger flexibility of the S=S bond in the SO_(3)S tetrahedra in comparison with the S–O bond in the SO4 tetrahedra.These findings indicate that constructing flexible bonds is an effective strategy to design highperformance nonlinear optical materials regardless of polarity.展开更多
Numerous studies of relationship between epigenomic features have focused on their strong correlation across the genome,likely because such relationship can be easily identified by many established methods for correla...Numerous studies of relationship between epigenomic features have focused on their strong correlation across the genome,likely because such relationship can be easily identified by many established methods for correlation analysis.However,two features with little correlation may still colocalize at many genomic sites to implement important functions.There is no bioinformatic tool for researchers to specifically identify such feature pairs.Here,we develop a method to identify feature pairs in which two features have maximal colocalization minimal correlation(MACMIC)across the genome.By MACMIC analysis of 3306 feature pairs in 16 human cell types,we reveal a dual role of CCCTC-binding factor(CTCF)in epigenetic regulation of cell identity genes.Although super-enhancers are associated with activation of target genes,only a subset of super-enhancers colocalized with CTCF regulate cell identity genes.At super-enhancers colocalized with CTCF,CTCF is required for the active marker H3 K27 ac in cell types requiring the activation,and also required for the repressive marker H3 K27 me3 in other cell types requiring repression.Our work demonstrates the biological utility of the MACMIC analysis and reveals a key role for CTCF in epigenetic regulation of cell identity.The code for MACMIC is available at https://github.com/bxia888/MACMIC.展开更多
Two fluoride sulfates,K_(2)Mn_(3)(SO_(4))_(3)F_(2)·4H_(2)O(Ⅰ) and Rb_(2)Mn_(3)(SO_(4))_(3)F_(2)·2H_(2)O (Ⅱ) are obtained by water solution method.Single-crystal X-ray diffraction analysis indicated that th...Two fluoride sulfates,K_(2)Mn_(3)(SO_(4))_(3)F_(2)·4H_(2)O(Ⅰ) and Rb_(2)Mn_(3)(SO_(4))_(3)F_(2)·2H_(2)O (Ⅱ) are obtained by water solution method.Single-crystal X-ray diffraction analysis indicated that they crystallize in space groups of Cmc2_(1.)Their structures feature a pseudo-KTP structure consisting of interconnecting[Mn_(3)(SO_(4))3F_(2)(H_(2)O)2]_(∞) layers,which are further packing along the a axis with alkali metal cations balancing the charges.The structure relationships between the two compounds are discussed.Secondharmonic generation measurements manifest that Ⅰ and Ⅱ have similar second-harmonic generation responses of about 0.2 and 0.25 times that of KH_(2)PO_(4).展开更多
文摘The experiments of single factor evaluation method, principal component analysis and voronoi area weighting factor method on the sample data of Liangzi Lake in October 2012 combined with the national surface water environment quality standards can get the map of comprehensive water quality distribution by Kriging interpolation. The analysis shows, the grades of comprehensive water quality gained by three methods are all only class III or class IV, and the quality of water is different from east and west that the water quality of east is better. However, the percent of IV class water is higher in the result of single factor evaluation method means class IV is the main grade of water quality. The result of principal component analysis shows the percent of class Ⅲ water is higher than other classes. The result of voronoi area weighting factor method shows the percent of IV class is higher than other classes. COD<sub>Mn</sub> is the main factor that influences the method of singal factor evaluation and reduces the grade of water quality overall. The effect of single factor is reduced by principal component analysis, and the analysis on water quality is more accurate. The voronoi area weighing factor method reduces the effect of single factor and extends the content, can make a comprehensive evaluation on water quality.
基金This work has been financially supported by the National Natural Science Foun-dation of China (No.51972293,51772039,and 21902189)Key Scientific Research Projects of Universities in Henan Province (21A150062)Young Backbone Teacher of Zhongyuan University of Technology.
文摘Development and utilization of hydrogen energy is an effective way to achieve carbon neutrality,only hydrogen production through electrolytic water splitting meets the goal of zero carbon emission.To facilitate the large-scale commercialization of water splitting devices,the development of highly efficient and low-cost catalysts to reduce the energy consumption is essential.MoS_(2)has been regarded as a promising electrocatalyst to replace platinum in hydrogen evolution reaction due to its low price and unique 2D layered structure.However,the poor conductivity and inert basal planes of MoS_(2)limited its wide-spread application.Recently,researches have demonstrated that the conductivity and active sites of MoS_(2)can be improved by heteroatoms doping or constructing of heterogeneous structures.In this review,the recent progress of Mo-based catalysts are summarized centered on MoS_(2)based on interface engineering and anion engineering,including MoS_(2)–MoO_(2),MoS_(2)–Mo_(2)C,MoS_(2)–MoN_(x),MoS_(2)–MoP,and MoS_(2)–MoSe_(2).The preparation method,structure,and performance of the catalysts are introduced and the possible mechanism behind the improved catalytic activity are revealed to give readers an overall comprehension on the progress of the Mo-based electrocatalysts for hydrogen evolution reaction.In addition,an outlook on future opportunities and development directions of Mo-based catalysts are proposed to facilitate the development of Mo-based catalysts for hydrogen production.
基金supported by the National Natural Science Foundation of China (No. 31171812)
文摘Bacterial blight, caused by Xanthomonas oryzae pv. oryzae(Xoo), is one of the most destructive diseases of rice(Oryza sativa L.) worldwide. The type III secretion system(T3SS) of Xoo, encoded by the hrp(hypersensitive response and pathogenicity) genes, plays critical roles in conferring pathogenicity in host rice and triggering a hypersensitive response(HR) in non-host plants. To investigate the major genes conferring the pathogenicity and avirulence of Xoo, we previously constructed a random Tn5-insertion mutant library of Xoo strain PXO99A. We report here the isolation and characterization of a Tn5-insertion mutant PXM69. Tn5-insertion mutants were screened on indica rice JG30, which is highly susceptible to PXO99A, by leaf-cutting inoculation.Four mutants with reduced virulence were obtained after two rounds of screening. Among them, the mutant PXM69 had completely lost virulence to the rice host and ability to elicit HR in non-host tobacco. Southern blotting analysis showed a single copy of a Tn5-insertion in the genome of PXM69. PCR walking and sequencing analysis revealed that the Tn5 transposon was inserted at nucleotide position 70,192–70,201 in the genome of PXO99A, disrupting the type III hrc(hrp-conserved) gene hrcQ, the first gene in the D operon of the hrp cluster in Xoo. To confirm the relationship between the Tn5-insertion and the avirulence phenotype of PXM69, we used the marker exchange mutagenesis to create a PXO99Amutant, ΔhrcQ::KAN, in which the hrcQ was disrupted by a kanamycin-encoding gene cassette at the same site as that of the Tn5-insertion. ΔhrcQ::KAN showed the same phenotype as mutant PXM69. Reintroduction of the wild-type hrcQ gene partially complemented the pathogenic function of PXM69. RT-PCR and cellulase secretion assays showed that the Tn5-disruption of hrcQ did not affect transcription of downstream genes in the D operon and function of the type II secretion system. Our results provide new insights into the pathogenic functions of clustered hrp genes in Xoo.
基金the National Natural Science Foundation of China(22122507,22193042,21833010,61975207,and 21921001)the Natural Science Foundation of Fujian Province(2022J02012)+2 种基金the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Y202069)the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(ZDBS-LY-SLH024)Fujian Institute of Innovation(FJCXY18010201)in Chinese Academy of Sciences.
文摘Deep-ultraviolet(deep-UV)nonlinear optical(NLO)crystals are of current interest because they play an indis-pensable role in modern scientific equipment.Searching these crystals was traditionally limited toπ-conjugated systems,such as borates and carbonates.In 2019,our group reported two non-π-conjugated sulfates as new sources of deep-UV NLO crystals for the first time.In this mini review,we provide a comprehensive overview of the recent development of non-π-conjugated NLO sulfates with deep-UV absorption edge in aspect of synthesis methods,crystal structures,thermal stability,and optical performance.Besides,we conclude the crucial structure-property relationships,and further give some prospects for exploring non-π-conjugated NLO sulfates with deep-UV absorption edge with high thermal stability,enhanced second-order NLO effects,birefringence,etc.We believe that this mini review will not only facilitate researchers to design superior non-π-conjugated NLO sulfates with deep-UV absorption edge but also shed useful insights on the explorations of other non-π-conjugated deep-UV NLO crystal systems.
基金the National Natural Science Foundation of China(22122507,21833010,61975207 and 21921001)the Youth Innovation Promotion of Chinese Academy of Sciences(Y202069)+1 种基金the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(ZDBS-LY-SLH024)Fujian Institute of Innovation(FJCXY18010201)in Chinese Academy of Sciences。
文摘High-performance bi-functional materials are in urgent demand for the next-generation integrated optical devices.In this work,we successfully synthesized the first tricyanomelaminate with bi-functional optical responses,namely Cs_(3)C_(6)N_(9)•H_(2)O(I),from its analogue Na_(3)C_(6)N_(9)•3H_(2)O by a facile ion exchange method.In contrast to Na_(3)C_(6)N_(9)•3H_(2)O,I realizes an optimal arrangement of𝜋π-conjugated(C_(6)N_(9))3−anion groups in its crystal structure.As a result,the second-order nonlinear optical(NLO)response is greatly enhanced from nearly zero of Na_(3)C_(6)N_(9)•3H_(2)O to∼9.8×KH_(2)PO_(4)of I.Furthermore,I exhibits a giant linear optical anisotropic response(i.e.birefringence)of 0.52 at the wavelength of 550 nm.Both responses are almost the largest among the inorganic compounds ofπ-conjugated rings,which indicates that I has great potential as a bi-functional optical crystal.Structural and theoretical analyses reveal the microscopic origin of excellent optical properties.This work would attract a lot of interest to the persistently neglected potential of tricyanomelaminates as linear optical and NLO crystals.
基金the financial support from the National Natural Science Foundation of China(grant Nos.51971227,51974288,and 52174380)the National Key Research and Development Program of China(grant No.2021YFA0716303)+1 种基金the Science and Technology Project of Fujian Province(grant No.2020T3037)China’s Manned Space Station Project,and the Space Utilization System of China Manned Space Engineering(grant No.KJZ-YY-NCL06).
文摘Solidification experiments were performed with Lead-Aluminum immiscible alloy under the effect of composite electric and magnetic fields(CEMFs).The results demonstrate that CEMFs not only decrease the size of minority phase particles(MPPs)but also promote a more uniform distribution of the MPPs.A theoretical model was built to describe the microstructure evolution during cooling the immiscible alloy.The solidification process of Pb-0.4 wt.%Al alloy under the effect of the CEMFs was simulated.The numerical results are well consistent with the experimental data.These results demonstrate that CEMFs affect the solidification process through changing melt convection and the nucleation behavior of minority phase droplets(MPDs).On one hand,the CEMFs can inhibit the convection and lead to the homogeneous distribution of MPPs along the radial direction of the sample.On the other hand,the CEMFs can increase the nucleation driving force for the MPDs,which decreases the average radius of MPDs and boosts the formation of dispersed solidification structures.This research indicates that the application of CEMFs is a promising strategy for controlling the microstructure of immiscible alloys.
基金the financial support from the National Natural Science Foundation of China(22122507,22193042,21833010,61975207,and 21921001)the Natural Science Foundation of Fujian Province(2022J02012)+2 种基金the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Y202069)the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(ZDBS-LY-SLH024)Fujian Institute of Innovation(FJCXY18010201)in Chinese Academy of Sciences.
文摘1.Text 2D van der Waals materials possess intriguing features[1],especially optically,such as high nonlinear optical responses[2],broadband spectral response[3],and accessible exciton effects[4].Unlike conventional 2D materials with in-plane isotropy,such as graphene and M0S_(2),2D van der Waals materials with in-plane anisotropic possess in-plane low symmetry structure,inducing the in-plane anisotropic physical properties.Meanwhile,they can be easily moved to various substrates without lattice-matching problems.
基金supported by the National Natural Science Foundation of China(22122507,61975207,22193042,21833010,and 21921001)the Natural Science Foundation of Fujian Province(2022J02012)+2 种基金the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Y202069)the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(ZDBS-LYSLH024)the China Postdoctoral Science Foundation(2023M743498)。
文摘There is a pressing demand for the development of novel birefringent crystals tailored for compact optical components,especially for crystals exhibiting large birefringence across a range of temperatures.This has commonly been achieved by introducing various deformable groups with high polarizability anisotropy.In this study,we combined both rigid and deformable groups to synthesise a new birefringent crystal,Al_(2)Te_(2)MoO_(10),which demonstrates an exceptional birefringence value of 0.29@550 nm at room temperature.Not only is this higher birefringence than that of commercial crystals,but Al_(2)Te_(2)MoO_(10)exhibits excellent birefringence stability over a wide temperature range,from 123 to 503 K.In addition,the first-principles theory calculations and structural analyses suggest that although the rigid AlO_(6)groups do not make much contribution to the prominent birefringence,they nonetheless played a role in maintaining the structural anisotropy at elevated temperatures.Based on these findings,this paper proposes a novel structural design strategy to complement conventional approaches for developing optimal birefringent crystals under various environmental conditions.
基金supported by the National Nature Science Foundation of China(21833010,61975207,21622101,21921001,21525104,and 51662013)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB20000000 and XDB20010200)+5 种基金the Natural Science Foundation of Fujian Province(2018H0047)the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(ZDBS-LY-SLH024)the Natural Science Foundation of Guangxi Province(2018GXNSFDA281015)the National Key Research and Development Program of China(2019YFA0210400)Key Laboratory of Functional Crystals and Laser Technology,TIPC,CAS(FCLT 202003)Key Laboratory of New Processing Technology for Nonferrous Metal&Materials,Ministry of Education/Guangxi Key Laboratory of Optical and Electronic Materials and Devices(20KF-11).
文摘Nonlinear optical(NLO)switchable materials have attracted intense attention because of their promising applications in optoelectronic devices.However,previous studies are mainly limited to molecular-based compounds that usually exhibit narrow bandgaps.Here,we report all-inorganic Li_(9)Na_(3)Rb_(2)(SO_(4))_(7) as an ultrawide-bandgap NLO switchable material.
基金the National Natural Science Foundation of China(No.21902189)Key Scientific Research Projects of Universities in Henan Province(No.21A150062)+1 种基金Young Backbone Teacher of Zhongyuan University of Technology(No.2020XQG09)the Fundamental Research Funds of Zhongyuan University of Technology(No.K2020YY003).
文摘Single-atom catalysts with precise structure and tunable coordination nature provide opportunities for developing novel catalytic centers and understanding reaction mechanisms.Herein,hollow Co_(9)S_(8)polyhedrons with lattice-confined Ru single atoms(Ru-Co_(9)S_(8))are fabricated.Aberration-corrected scanning transmission electron microscopy and X-ray absorption spectroscopy verify the isolated Ru atoms are confined in Co_(9)S_(8)to form Co-S-Ru catalytic centers.Theoretical calculations indicate that the oxygen evolution reaction(OER)and oxygen reduction reaction(ORR)energy barriers are extensively reduced,the d-band center of Co_(9)S_(8)downshifts from the Fermi level,therefore boosting the desorption of O-containing intermediates.Consequently,the Ru-Co_(9)S_(8)exhibits an ultralow overpotential of 163 mV at 10 mA·cm^(−2)for OER and could catalyze a rechargeable Zn-air battery with a high-power density of 92.0 mW·cm^(−2).This work provides a promising approach for designing novel bifunctional catalytic active centers for energy conversion.
基金This work was financially supported by the National Natural Science Foundation of China(22122507,21833010,61975207,22193042,and 21921001)the Natural Science Foundation of Fujian Province(2022J02012)+2 种基金the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Y202069)the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(ZDBS-LY-SLH024)as well as Fujian Institute of Innovation(FJCXY18010201)in the Chinese Academy of Sciences.
文摘The majority of plant disease resistance （R） genes encode proteins that share common structural features. However, the transcription activator-like effector （TALE）-associated executor type R genes show no considerable sequence homology to any known R genes. We adopted a map-based cloning approach and TALE-based technology to isolate and characterize Xa23, a new executor R gene derived from wild rice （Oryza rufipogon） that confers an extremely broad spectrum of resistance to bacterial blight caused by Xanthomonas oryzae pv. oryzae （Xoo）. Xa23 encodes a 113 amino acid protein that shares 50% identity with the known executor R protein XA10. The predicted transmembrane helices in XA23 also overlap with those of XA10. Unlike XalO, however, Xa23 transcription is specifically activated by AvrXa23, a TALE present in all examined Xoo field isolates. Moreover, the susceptible xa23 allele has an identical open reading frame of Xa23 but differs in promoter region by lacking the TALE binding element （EBE） for AvrXa23. XA23 can trigger a strong hypersensitive response in rice, tobacco, and tomato. Our results provide the first evidence that plant genomes have an executor R gene family of which members execute their function and spectrum of disease resistance by recognizing the cognate TALEs in the pathogen.
基金the National Natural Science Foundation of China(No.51772039)the Fundamental Research Funds for the Central University(No.DUT18LK13)The Research Center for Solar Light Energy Conversion,Kyushu Institute of Technology,Japan also supports this work financially.
文摘Designing a highly efficient non-precious based oxygen reduction reaction(ORR)electrocatalyst is critical for the commercialization of various sustainable energy storage and conversion devices such as metal-air batteries and fuel cells.Herein,we report a convenient strategy to synthesis Fe3O4 embedded in N doped hollow carbon sphere(NHCS)for ORR.What's interesting is that the carbon microsphere is composed of two-dimensional(2D)nanoplate that could provide more exposed active sites.The usage of solid ZnO nanowires as zinc source is crucial to obtain this structure.The Fe3O4@NHCS-2 exhibits better catalytic activity and durability than the commercial PtC catalyst.Moreover,it further displays high-performance of Zn-air batteries as a cathode electrocatalyst with a high-power density of 133 mW·cm^-2 and high specific capacity of 701 mA·h·g^-1.The special hollow structure composed 2D nanoplate,high surface area,as well as synergistic effect between the high active Fe3O4 nanoparticles and N-doped matrix endows this outstanding catalytic activity.The work presented here can be easily extended to prepare metal compounds decorated carbon nanomaterials with special structure for a broad range of energy storage and conversion devices.
基金supported by the National Natural Science Foundation of China(nos.21833010,61975207,21921001,21971238,51872297,and 51890864)the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(no.ZDBS-LY-SLH024)+3 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(nos.XDB20010200 and XDB20000000)Fujian Institute of Innovation(no.FJCXY18010201)in Chinese Academy of Sciences,the National Key Research and Development Program of China(no.2019YFA0210400)Key Laboratory of Functional Crystals and Laser Tech-nology,TIPC,CAS(no.FCLT 202003)as well as Key Laboratory of New Processing Technology for Nonferrous Metal&Materials,Ministry of Education/Guangxi Key Laboratory of Optical and Electronic Materials and Devices(no.20KF-11).
文摘Conventional wisdom says that nonpolar structures do not favorably produce strong second-harmonic generation(SHG)responses since the polarization in their microscopic functional groups are counteracted.Herein,we report the first nonlinear optical thiosulfate,Na_(10)Cd(NO_(3))_(4)(SO_(3)S)_(4),which crystallizes in a nonpolar space group of P−4.However,this thiosulfate exhibits a strong SHG response of about 4.2 times that of the benchmark KH2PO4,which is larger than those of polar sulfates.According to first-principles calculations and a flexible dipole model,the SHG enhancement is mainly ascribed to the larger flexibility of the S=S bond in the SO_(3)S tetrahedra in comparison with the S–O bond in the SO4 tetrahedra.These findings indicate that constructing flexible bonds is an effective strategy to design highperformance nonlinear optical materials regardless of polarity.
基金supported in part by the grants from National Institutes of Health(NIH)(Grant Nos.R01GM125632 to KC,R01HL133254 and R01HL148338 to JPC and KC,R01CA207098 and R01CA207109 to ML)QC is supported by the U.S.Department of Defense(Grant Nos.W81XWH17-1-0357 and W81XWH-19-1-0563)+2 种基金the American Cancer Society(Grant No.RSG-15-192-01)the National Cancer Institute(NCI),NIH(Grant Nos.R01CA208257 and P50CA180995 DRP)the Northwestern University Polsky Urologic Cancer Institute,USA
文摘Numerous studies of relationship between epigenomic features have focused on their strong correlation across the genome,likely because such relationship can be easily identified by many established methods for correlation analysis.However,two features with little correlation may still colocalize at many genomic sites to implement important functions.There is no bioinformatic tool for researchers to specifically identify such feature pairs.Here,we develop a method to identify feature pairs in which two features have maximal colocalization minimal correlation(MACMIC)across the genome.By MACMIC analysis of 3306 feature pairs in 16 human cell types,we reveal a dual role of CCCTC-binding factor(CTCF)in epigenetic regulation of cell identity genes.Although super-enhancers are associated with activation of target genes,only a subset of super-enhancers colocalized with CTCF regulate cell identity genes.At super-enhancers colocalized with CTCF,CTCF is required for the active marker H3 K27 ac in cell types requiring the activation,and also required for the repressive marker H3 K27 me3 in other cell types requiring repression.Our work demonstrates the biological utility of the MACMIC analysis and reveals a key role for CTCF in epigenetic regulation of cell identity.The code for MACMIC is available at https://github.com/bxia888/MACMIC.
基金financially supported by the National Natural Science Foundation of China(Nos.21833010,21525104,21971238,61975207,21921001)the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(No.ZDBS-LYSLH024)+1 种基金Key Laboratory of Functional Crystals and Laser Technology,TIPC,CAS(No.FCLT 202003)Key Laboratory of New Processing Technology for Nonferrous Metal&Materials,Ministry of Education/Guangxi Key Laboratory of Optical and Electronic Materials and Devices(No.20KF-11)。
文摘Two fluoride sulfates,K_(2)Mn_(3)(SO_(4))_(3)F_(2)·4H_(2)O(Ⅰ) and Rb_(2)Mn_(3)(SO_(4))_(3)F_(2)·2H_(2)O (Ⅱ) are obtained by water solution method.Single-crystal X-ray diffraction analysis indicated that they crystallize in space groups of Cmc2_(1.)Their structures feature a pseudo-KTP structure consisting of interconnecting[Mn_(3)(SO_(4))3F_(2)(H_(2)O)2]_(∞) layers,which are further packing along the a axis with alkali metal cations balancing the charges.The structure relationships between the two compounds are discussed.Secondharmonic generation measurements manifest that Ⅰ and Ⅱ have similar second-harmonic generation responses of about 0.2 and 0.25 times that of KH_(2)PO_(4).
