Herein we demonstrate the construction of three types of parallel gold nanorod(AuNR) clusters using a DNA origami rod(DOR) as the template. Based on the precise control over the position of capture strands on DOR, num...Herein we demonstrate the construction of three types of parallel gold nanorod(AuNR) clusters using a DNA origami rod(DOR) as the template. Based on the precise control over the position of capture strands on DOR, number and orientation of the AuNR clusters can be well engineered, as evidenced by biological transmission electron microscope(TEM). Importantly, the AuNR clusters exhibit chiroptical responses which are strongly affected by the number of AuNR on rod-like DNA origami.展开更多
Self-assembly cluster compound [WS4Cu3(PPh2Py)3Br]2·CH3OH (1) was synthesized by the reaction of (NH4)2WS4, CuBr and diphenyl-2-pyridyl-phosphine (PPh2Py) in CH3OH solution under a purified nitrogen atmosphere us...Self-assembly cluster compound [WS4Cu3(PPh2Py)3Br]2·CH3OH (1) was synthesized by the reaction of (NH4)2WS4, CuBr and diphenyl-2-pyridyl-phosphine (PPh2Py) in CH3OH solution under a purified nitrogen atmosphere using standard Schlenk techniques. Its structure was determined by X-ray crystallography. It crystallizes in the triclinic crystal system P-1 space group with a=1.178 6 (1) nm, b=1.302 6 (1) nm, c=1.991 7 (2) nm, α=74.671 (7)-, β=86.188 (8)-, γ=64.141 (6)-, V=2.649 5 (5) nm3, Z=1. The W center is slightly distorted from tetrahedral coordination geometry, and the structure is built up from three [Cu(PPh2Py)]+ units bridged by WS 24- multifunctional ligand to form a tetranuclear symmetrical cube-like molecule. Measurement of the nonlinear optical (NLO) properties using the Z-scan technique with an 8 ns pulsed laser at 532 nm shows that the compound possesses NLO absorption and effective self-focusing effect at α2=6.7×10-11 m/W and n2=5.64×10-18 m2/W in a 1.5×10-4 mol/L DMF solution.展开更多
With the rapid development of space technology and the increasing demand for space missions,the traditional spacecraft manufacturing,deployment and launch methods have been unable to meet existing needs.In-space assem...With the rapid development of space technology and the increasing demand for space missions,the traditional spacecraft manufacturing,deployment and launch methods have been unable to meet existing needs.In-space assembly(ISA)technologies can effectively adapt to the assembly of large space structures,improve spacecraft performance,and reduce operating costs.In this paper,the development and technologies for ISA are reviewed.ISA is classified from multiple angles,and the research status of ISA is shown clearly through the visual mapping knowledge domain.Then the development status of autonomous robot assembly in the United States,Europe,Japan,Canada and China is reviewed.Furthermore,the key technologies of ISA are analyzed from three aspects:assembly structure design,robot technologies and integrated management technologies.ISA technologies are still facing major challenges and need to be further explored to promote future development.Finally,future development trends and potential applications of ISA are given,which show that ISA will play a vital role in human space exploration in the future.展开更多
The self-assembly of clusters in inorganic systems is an interesting subject. The self-assembly of big molecules has been well established in biological systems. In addition, the coordination chemistry of metal-sulfur...The self-assembly of clusters in inorganic systems is an interesting subject. The self-assembly of big molecules has been well established in biological systems. In addition, the coordination chemistry of metal-sulfur-nitrogen cluster complexes has been a very active and attracting field for many years as a result of the novelty and versatility of the crystal structures and reactivities of such clusters, as well as their potential applications as the models for the active sites in non-heme proteins. At the same time, there is currently considerable interest in the formation of metal complexes with heterocyclic ligands because of the diverse characteristics of ligands and their consequential wide range of applications.展开更多
The coupling dynamics problem between the walking robot and large space structures during on-orbit assembly is investigated in this paper.The quadruped walking robot is first chosen as the assembly robot,which is equi...The coupling dynamics problem between the walking robot and large space structures during on-orbit assembly is investigated in this paper.The quadruped walking robot is first chosen as the assembly robot,which is equivalent to a spring-mass-damper system with seven degrees of freedom.The primary goal of the robot is to stably walk on a large space structure while carrying an assembly module to a designated location for assembly.Combining with the characteristic of incrementally increasing of the large space structure,a revival dynamic modeling method is then presented.On this basis,the coupled dynamic model of the robot and the space truss structure is developed.To simulate robot walking,the motion gait of the quadruped walking robot is designed as a diagonal alternating gait.The moving load are considered as disturbance inputs associated with the truss,and an active vibration controller is developed to deal with the disturbance.The numerical simulation of a quadruped walking robot moving on a space truss structure is finally presented with different cases.The results demonstrate that the quadruped walking robot movement has a significant influence on the space truss structure,and the mutual disturbances between the two are effectively suppressed by the proposed controller.展开更多
The elucidation of hierarchical assembly structure of metal nanoclusters is of fundamental importance in the context of bottom-up fabrication and functionalization.While recent studies have provided valuable insights ...The elucidation of hierarchical assembly structure of metal nanoclusters is of fundamental importance in the context of bottom-up fabrication and functionalization.While recent studies have provided valuable insights into the multiscale assembly patterns of gold or silver-based nanoclusters,the success in achieving similar results for copper analogues has been notably limited.Herein,by virtue of a slow-ligand-release strategy,a copper nanocluster denoted as[Cu_(66)Cl_(8)(PPh_(3))_(8)(SC_(2)H_(5))_(32)H_(24)](SbF_(6))_(2)was synthesized,resulting in the formation of fresh hierarchical assembly structures in one-pot.The arrangement of the metal atoms within the cluster reveals an orderly of 16 Cu4 squares,representing a rare copper nanocluster comprising square motifs.Additionally,the ligands(phosphine,thiolate,and halide)coordinate to the surface of the cluster in a regiospecific manner,displaying square patterns as well.The self-assembly facilitated by the C-H⋅⋅⋅F interaction between the cluster moieties and SbF_(6)−anions further induces the formation of three-dimensional cubes and eventually large nanocrystals.Density functional theoretical(DFT)calculations reveal that hydride atoms with low chemical shifts typically exhibit short Cu-H distances.The cluster demonstrates moderate stability and high catalytic activity in the chemoselective hydrogenation of cyclohexanone under mild conditions.展开更多
Circularly polarized luminescence(CPL)materials have been extensively studied in recent years owing to their widespread applications in 3D display,optical storage,optical anti-counterfeiting,and biological imaging,etc...Circularly polarized luminescence(CPL)materials have been extensively studied in recent years owing to their widespread applications in 3D display,optical storage,optical anti-counterfeiting,and biological imaging,etc.Copper(Ⅰ)clusters have emerged as a promising candidate for CPL materials,driven by their cost-effectiveness,superior luminescent properties,precise structure,and low toxicity.Nevertheless,the poor environmental stability of copper(Ⅰ)clusters renders their synthesis and preservation challenging,thereby significantly impeding their advancement.Herein,we have designed and synthesised a chiral double-coordinated ligand in order to construct copper(Ⅰ)cluster nodes that can be further assembled.As anticipated,by utilizing stepwise assembly strategy,a Cu_(4)cluster node co-modified by chiral alkynyl ligands and triphenylphosphine was further assembled with Cd^(2+)ions to obtain 2D layers structure,L/D-Cu_(4)-Cd.The L/D-Cu_(4)-Cd exhibits excellent stability and optical properties,including bright yellow emission,solvent-responsive luminescence,and CPL activity with a maximum glumup to 2.0×10^(-3),which shows potential applications in the WLED and WCP-light.More interestingly,the material also exhibits deflection ability towards different wavelengths of linearly polarized light,showing certain potential in the preparation of circular polarizer.展开更多
Aggregation-induced emission(AIE)and thermally activated delayed fluorescence(TADF)are two optoelectronic properties with great potential for applications.However,metal nanoclusters exhibiting both AIE and TADF charac...Aggregation-induced emission(AIE)and thermally activated delayed fluorescence(TADF)are two optoelectronic properties with great potential for applications.However,metal nanoclusters exhibiting both AIE and TADF characteristics have not been extensively studied.This study investigates a binary cocrystal system based on silver nanoclusters—Ag_(6)(Et_(2)NCS_(2))6·[Ag_(11)(AdmS)_(3)(Et_(2)NCS_(2))6]_(2)(1-Ag_(6)·(Ag_(11))_(2)),aiming to explore the synergistic effects between flexible-alkyl dithiol and rigid monothiol ligands.Due to the introduction of Ag_(6)structures,the system exhibits enhanced stability and modulated optical properties.The binary tricluster 1-Ag_(6)·(Ag_(11))_(2)demonstrates significant AIE behavior,with an approximately 15-fold increase in intensity when the water volume fraction(fw)is 60%.Single-crystal X-ray diffraction analysis indicates that the enhanced AIE effect originates from intercluster hydrogen bonding interactions,which drive the self-assembly of sub-clusters and form hierarchical structures,thereby suppressing ligand rotation.In addition,the system exhibits the TADF phenomenon in the temperature range of 100−175 K.In order to further investigate the effect of ligand variations on optical properties,two unitary clusters,Ag_(11)(AdmS)_(3)(Et_(2)NCS_(2))6(2-Ag_(11)-AS)and Ag_(11)(tBuS)_(3)(Et_(2)NCS_(2))6(3-Ag_(11)-BS),are synthesized,and their roles in regulating optoelectronic properties are explored through ligand exchange reactions.This study provides important insights for the development of efficient luminescent materials with AIE and TADF properties,highlighting the critical roles of ligand exchange and structural configuration.展开更多
Understanding the mechanisms of community assembly is a key question in ecology.Metal pollution may result in significant changes in bird community structure and diversity,with implications for ecosystem processes and...Understanding the mechanisms of community assembly is a key question in ecology.Metal pollution may result in significant changes in bird community structure and diversity,with implications for ecosystem processes and function.However,the relative importance of these pro-cesses in shaping the bird community at the polluted area is still not clear.Here,we explored bird species richness,functional,and phylogenetic diversity,and the assembly processes of community at the mine region of southwest China.Our results showed that the 3 dimensions of diversity at the mine area were lower than that at the reference sites.In the community assembly,the result was O<NRI/NFR1<1.96,which indicated deterministic processes(environmental filtering)might drive community clustering.The results of the neutral community model,and normalized stochasticity ratio,showed the dominant role of stochastic processes in shaping the bird community assembly.We further quanti-fied the community-level habitat niche breadth(Bcom),and we found that there was no difference in Bcom-value between the mine area and reference sites.This indicates that the bird communities at the mine area and 3 reference sites were not subjected to extreme environmental selection(same or different resource allocation)to form a highly specialized niche.These findings provide insights into the distribution patterns and dominant ecological processes of bird communities under metal exposure,and extend the knowledge in community assembly mechanisms of bird communities living in the mine area.展开更多
A new copper-thiolate cluster assembled framework[Cu2(μ4-SCH3)Cl]n(1),has been solvothermally synthesized through in situ reaction viz.,in situ ligand generation and metal reduction.Compound 1 represents the first 3 ...A new copper-thiolate cluster assembled framework[Cu2(μ4-SCH3)Cl]n(1),has been solvothermally synthesized through in situ reaction viz.,in situ ligand generation and metal reduction.Compound 1 represents the first 3 D framework based on Atlas-sphere functionalized by singleμ2-Cl groups.DOS calculation reveals the interaction of electronic structures.It is found that the HOMO is mainly distributed on Cl,Cu and S bonding orbitals,while the LUMO is dominated by Cu-Cl antibonding orbitals.展开更多
This is a further development work on grouping of printed circuit boards(PCBs)for Surface Mount Assembly in the electronic industry.The arrangement of PCBs among several surface mount machine lines is a typical kind o...This is a further development work on grouping of printed circuit boards(PCBs)for Surface Mount Assembly in the electronic industry.The arrangement of PCBs among several surface mount machine lines is a typical kind of group technology(GT)problem.From literatures,there are various clustering techniques developed to solve the clustering problems.In this paper,fuzzy c-means clustering(FCM)is used to solve the PCBs grouping problem.Applying them in a real problem compares the results of the two methods.The result shows that there should be a systematic method to arrange the scheduling of PCB assemblies in electronic industry to improve the operations planning process.展开更多
Cobalt doped ZnO film assembled by the nanoparticles was prepared by low energy cluster beam deposition.The microstructure,phase structure and optical properties were investigated for the nanostructured films.The resu...Cobalt doped ZnO film assembled by the nanoparticles was prepared by low energy cluster beam deposition.The microstructure,phase structure and optical properties were investigated for the nanostructured films.The results show that the nanostructured film was assembled by monodisperse spherical nanoparticles with average diameter of about 29.3 nm which are distributed uniformly and compactly.The results of X-ray diffraction(XRD)show that cobalt doped ZnO nanostructured film is indexed to a wurtzite structure of ZnO,and no Co-phase structure and other phases are observed.The UV-visible absorption spectra show that the optical band-gap of the film is broadened after doping.展开更多
Streptomyces has enormous potential to produce novel natural products(NPs)as it harbors a huge reservoir of uncharacterized and silent natural product biosynthetic gene clusters(BGCs).However,the lack of efficient gen...Streptomyces has enormous potential to produce novel natural products(NPs)as it harbors a huge reservoir of uncharacterized and silent natural product biosynthetic gene clusters(BGCs).However,the lack of efficient gene cluster engineering strategies has hampered the pace of new drug discovery.Here,we developed an easy-to-use,highly flexible DNA assembly toolkit for gene cluster engineering.The DNA assembly toolkit is compatible with various DNA assembling approaches including Biobrick,Golden Gate,CATCH,yeast homologous recombination-based DNA assembly and homing endonuclease-mediated assembly.This compatibility offers great flexibility in handling multiple genetic parts or refactoring large gene clusters.To demonstrate the utility of this toolkit,we quantified a library of modular regulatory parts,and engineered a gene cluster(act)using characterized promoters that led to increased production.Overall,this work provides a powerful part assembly toolkit that can be used for natural product discovery and optimization in Streptomyces.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 21504053, 21661162001, 21673139, 91527304, 21722502)Shanghai Pujiang Talent Project (No. 16PJ1402700)+1 种基金the Innovation Fund from Joint Research Center for Precision Medicine set up by Shanghai Jiao Tong University & Affiliated Sixth People's Hospital South Campus (No. IFPM 2016B001)the special program for collaborative innovation in Shanghai University of Medicine & Health Sciences (SPCI-17-15-001)
文摘Herein we demonstrate the construction of three types of parallel gold nanorod(AuNR) clusters using a DNA origami rod(DOR) as the template. Based on the precise control over the position of capture strands on DOR, number and orientation of the AuNR clusters can be well engineered, as evidenced by biological transmission electron microscope(TEM). Importantly, the AuNR clusters exhibit chiroptical responses which are strongly affected by the number of AuNR on rod-like DNA origami.
基金Project(2006FJ4235) supported by the Post-Doctoral Foundation of Hunan Province, China
文摘Self-assembly cluster compound [WS4Cu3(PPh2Py)3Br]2·CH3OH (1) was synthesized by the reaction of (NH4)2WS4, CuBr and diphenyl-2-pyridyl-phosphine (PPh2Py) in CH3OH solution under a purified nitrogen atmosphere using standard Schlenk techniques. Its structure was determined by X-ray crystallography. It crystallizes in the triclinic crystal system P-1 space group with a=1.178 6 (1) nm, b=1.302 6 (1) nm, c=1.991 7 (2) nm, α=74.671 (7)-, β=86.188 (8)-, γ=64.141 (6)-, V=2.649 5 (5) nm3, Z=1. The W center is slightly distorted from tetrahedral coordination geometry, and the structure is built up from three [Cu(PPh2Py)]+ units bridged by WS 24- multifunctional ligand to form a tetranuclear symmetrical cube-like molecule. Measurement of the nonlinear optical (NLO) properties using the Z-scan technique with an 8 ns pulsed laser at 532 nm shows that the compound possesses NLO absorption and effective self-focusing effect at α2=6.7×10-11 m/W and n2=5.64×10-18 m2/W in a 1.5×10-4 mol/L DMF solution.
基金supported in part by National Key R&D Program of China(No.2018YFB1304600)the Natural Science Foundation of China(No.51775541)CAS Interdisciplinary Innovation Team(No.JCTD-2018-11)。
文摘With the rapid development of space technology and the increasing demand for space missions,the traditional spacecraft manufacturing,deployment and launch methods have been unable to meet existing needs.In-space assembly(ISA)technologies can effectively adapt to the assembly of large space structures,improve spacecraft performance,and reduce operating costs.In this paper,the development and technologies for ISA are reviewed.ISA is classified from multiple angles,and the research status of ISA is shown clearly through the visual mapping knowledge domain.Then the development status of autonomous robot assembly in the United States,Europe,Japan,Canada and China is reviewed.Furthermore,the key technologies of ISA are analyzed from three aspects:assembly structure design,robot technologies and integrated management technologies.ISA technologies are still facing major challenges and need to be further explored to promote future development.Finally,future development trends and potential applications of ISA are given,which show that ISA will play a vital role in human space exploration in the future.
基金Supported by the National Natural Science Foundation of China(Nos. 20476011 and 20371007).
文摘The self-assembly of clusters in inorganic systems is an interesting subject. The self-assembly of big molecules has been well established in biological systems. In addition, the coordination chemistry of metal-sulfur-nitrogen cluster complexes has been a very active and attracting field for many years as a result of the novelty and versatility of the crystal structures and reactivities of such clusters, as well as their potential applications as the models for the active sites in non-heme proteins. At the same time, there is currently considerable interest in the formation of metal complexes with heterocyclic ligands because of the diverse characteristics of ligands and their consequential wide range of applications.
基金supported by the National Natural Science Foundation of China(grant numbers 12472049,12232015)Guangdong Basic and Applied Basic Research Foundation(2024A1515010634).
文摘The coupling dynamics problem between the walking robot and large space structures during on-orbit assembly is investigated in this paper.The quadruped walking robot is first chosen as the assembly robot,which is equivalent to a spring-mass-damper system with seven degrees of freedom.The primary goal of the robot is to stably walk on a large space structure while carrying an assembly module to a designated location for assembly.Combining with the characteristic of incrementally increasing of the large space structure,a revival dynamic modeling method is then presented.On this basis,the coupled dynamic model of the robot and the space truss structure is developed.To simulate robot walking,the motion gait of the quadruped walking robot is designed as a diagonal alternating gait.The moving load are considered as disturbance inputs associated with the truss,and an active vibration controller is developed to deal with the disturbance.The numerical simulation of a quadruped walking robot moving on a space truss structure is finally presented with different cases.The results demonstrate that the quadruped walking robot movement has a significant influence on the space truss structure,and the mutual disturbances between the two are effectively suppressed by the proposed controller.
基金support from the National Key R&D Program of China(2023YFB3507100)National Natural Science Foundation of China(22301149)+6 种基金Program for Young Talents of Science and Technology in Universities of Inner Mongolia Autonomous Region(NJYT23035)start-up funding of Inner Mongolia University(10000-23112101/043)support from the National Natural Science Foundation of China(grant no.92261207,and NSFC Center for Single-Atom Catalysis under grant no.22388102)the New Cornerstone Science Foundation.Q.Y.W.thanks the China Postdoctoral Science Foundation Project(2023M732946)the Postdoctoral Fellowship Program of CPSF(GZB20230380)supported by the National Science Foundation(CHE-1905048)of the United Statesthe Beocat Research Cluster at Kansas State University,which is funded in part by NSF grants CHE-1726332,CNS-1006860,EPS-1006860,and EPS-0919443.
文摘The elucidation of hierarchical assembly structure of metal nanoclusters is of fundamental importance in the context of bottom-up fabrication and functionalization.While recent studies have provided valuable insights into the multiscale assembly patterns of gold or silver-based nanoclusters,the success in achieving similar results for copper analogues has been notably limited.Herein,by virtue of a slow-ligand-release strategy,a copper nanocluster denoted as[Cu_(66)Cl_(8)(PPh_(3))_(8)(SC_(2)H_(5))_(32)H_(24)](SbF_(6))_(2)was synthesized,resulting in the formation of fresh hierarchical assembly structures in one-pot.The arrangement of the metal atoms within the cluster reveals an orderly of 16 Cu4 squares,representing a rare copper nanocluster comprising square motifs.Additionally,the ligands(phosphine,thiolate,and halide)coordinate to the surface of the cluster in a regiospecific manner,displaying square patterns as well.The self-assembly facilitated by the C-H⋅⋅⋅F interaction between the cluster moieties and SbF_(6)−anions further induces the formation of three-dimensional cubes and eventually large nanocrystals.Density functional theoretical(DFT)calculations reveal that hydride atoms with low chemical shifts typically exhibit short Cu-H distances.The cluster demonstrates moderate stability and high catalytic activity in the chemoselective hydrogenation of cyclohexanone under mild conditions.
基金supported by the National Natural Science Foundation of China(92356304,92061201,21825106,U21A20277,22101264 and 22271130)China Postdoctoral Science Foundation(2021TQ0292)+1 种基金Zhongyuan Thousand Talents(Zhongyuan Scholars)Program of Henan Province(234000510007)Zhengzhou University。
文摘Circularly polarized luminescence(CPL)materials have been extensively studied in recent years owing to their widespread applications in 3D display,optical storage,optical anti-counterfeiting,and biological imaging,etc.Copper(Ⅰ)clusters have emerged as a promising candidate for CPL materials,driven by their cost-effectiveness,superior luminescent properties,precise structure,and low toxicity.Nevertheless,the poor environmental stability of copper(Ⅰ)clusters renders their synthesis and preservation challenging,thereby significantly impeding their advancement.Herein,we have designed and synthesised a chiral double-coordinated ligand in order to construct copper(Ⅰ)cluster nodes that can be further assembled.As anticipated,by utilizing stepwise assembly strategy,a Cu_(4)cluster node co-modified by chiral alkynyl ligands and triphenylphosphine was further assembled with Cd^(2+)ions to obtain 2D layers structure,L/D-Cu_(4)-Cd.The L/D-Cu_(4)-Cd exhibits excellent stability and optical properties,including bright yellow emission,solvent-responsive luminescence,and CPL activity with a maximum glumup to 2.0×10^(-3),which shows potential applications in the WLED and WCP-light.More interestingly,the material also exhibits deflection ability towards different wavelengths of linearly polarized light,showing certain potential in the preparation of circular polarizer.
基金supported by the National Natural Science Foundation of China(Nos.22488101 and 22071274).
文摘Aggregation-induced emission(AIE)and thermally activated delayed fluorescence(TADF)are two optoelectronic properties with great potential for applications.However,metal nanoclusters exhibiting both AIE and TADF characteristics have not been extensively studied.This study investigates a binary cocrystal system based on silver nanoclusters—Ag_(6)(Et_(2)NCS_(2))6·[Ag_(11)(AdmS)_(3)(Et_(2)NCS_(2))6]_(2)(1-Ag_(6)·(Ag_(11))_(2)),aiming to explore the synergistic effects between flexible-alkyl dithiol and rigid monothiol ligands.Due to the introduction of Ag_(6)structures,the system exhibits enhanced stability and modulated optical properties.The binary tricluster 1-Ag_(6)·(Ag_(11))_(2)demonstrates significant AIE behavior,with an approximately 15-fold increase in intensity when the water volume fraction(fw)is 60%.Single-crystal X-ray diffraction analysis indicates that the enhanced AIE effect originates from intercluster hydrogen bonding interactions,which drive the self-assembly of sub-clusters and form hierarchical structures,thereby suppressing ligand rotation.In addition,the system exhibits the TADF phenomenon in the temperature range of 100−175 K.In order to further investigate the effect of ligand variations on optical properties,two unitary clusters,Ag_(11)(AdmS)_(3)(Et_(2)NCS_(2))6(2-Ag_(11)-AS)and Ag_(11)(tBuS)_(3)(Et_(2)NCS_(2))6(3-Ag_(11)-BS),are synthesized,and their roles in regulating optoelectronic properties are explored through ligand exchange reactions.This study provides important insights for the development of efficient luminescent materials with AIE and TADF properties,highlighting the critical roles of ligand exchange and structural configuration.
文摘Understanding the mechanisms of community assembly is a key question in ecology.Metal pollution may result in significant changes in bird community structure and diversity,with implications for ecosystem processes and function.However,the relative importance of these pro-cesses in shaping the bird community at the polluted area is still not clear.Here,we explored bird species richness,functional,and phylogenetic diversity,and the assembly processes of community at the mine region of southwest China.Our results showed that the 3 dimensions of diversity at the mine area were lower than that at the reference sites.In the community assembly,the result was O<NRI/NFR1<1.96,which indicated deterministic processes(environmental filtering)might drive community clustering.The results of the neutral community model,and normalized stochasticity ratio,showed the dominant role of stochastic processes in shaping the bird community assembly.We further quanti-fied the community-level habitat niche breadth(Bcom),and we found that there was no difference in Bcom-value between the mine area and reference sites.This indicates that the bird communities at the mine area and 3 reference sites were not subjected to extreme environmental selection(same or different resource allocation)to form a highly specialized niche.These findings provide insights into the distribution patterns and dominant ecological processes of bird communities under metal exposure,and extend the knowledge in community assembly mechanisms of bird communities living in the mine area.
基金the National Natural Science Foundation of China(Nos.21861012 and 21603109)the Henan Joint Fund of the National Natural Science Foundation of China(No.U1404216)+6 种基金the Natural Science Foundation of Guizhou Education Commission(Nos.2018148 and 2018016)Guizhou Science&Technology Commission(Nos.20201Z005,20191157 and 20191156)the Natural Science Foundation of Shandong Provinceof China(No.ZR2016BM14)Tai’an Science&Technology Project(No.2016GX1046)the Postgraduate Foundation of Taishan University(No.Y2015-1-011)the Natural Science Foundation of Guizhou Minzu University(No.GZMU2019YB06)the Natural Science Foundation of Liaoning Shihua University(No.2019XJJL019)。
文摘A new copper-thiolate cluster assembled framework[Cu2(μ4-SCH3)Cl]n(1),has been solvothermally synthesized through in situ reaction viz.,in situ ligand generation and metal reduction.Compound 1 represents the first 3 D framework based on Atlas-sphere functionalized by singleμ2-Cl groups.DOS calculation reveals the interaction of electronic structures.It is found that the HOMO is mainly distributed on Cl,Cu and S bonding orbitals,while the LUMO is dominated by Cu-Cl antibonding orbitals.
文摘This is a further development work on grouping of printed circuit boards(PCBs)for Surface Mount Assembly in the electronic industry.The arrangement of PCBs among several surface mount machine lines is a typical kind of group technology(GT)problem.From literatures,there are various clustering techniques developed to solve the clustering problems.In this paper,fuzzy c-means clustering(FCM)is used to solve the PCBs grouping problem.Applying them in a real problem compares the results of the two methods.The result shows that there should be a systematic method to arrange the scheduling of PCB assemblies in electronic industry to improve the operations planning process.
基金Projects(1090406510674056+5 种基金1077407090606002)supported by the National Natural Science Foundation of ChinaProject(20080441042)supported by China Postdoctoral Science FoundationProject(200926)supported by Tonghua Normal University FoundationProject(2010CB923401)supported by the National Basic Research Program of ChinaProject(BK2008024)supported by the Natural Science Foundation of Jiangsu of Province,China
文摘Cobalt doped ZnO film assembled by the nanoparticles was prepared by low energy cluster beam deposition.The microstructure,phase structure and optical properties were investigated for the nanostructured films.The results show that the nanostructured film was assembled by monodisperse spherical nanoparticles with average diameter of about 29.3 nm which are distributed uniformly and compactly.The results of X-ray diffraction(XRD)show that cobalt doped ZnO nanostructured film is indexed to a wurtzite structure of ZnO,and no Co-phase structure and other phases are observed.The UV-visible absorption spectra show that the optical band-gap of the film is broadened after doping.
基金supported by the National Key Research and Development Program of China[2020YFA0906900,2018YFA0900700]Natural Science Foundation of China[31500069]+1 种基金the Chinese Academy of Sciences[No.QYZDB-SSW-SMC050,No.XDB0480000 of the Strategic Priority Research Program]CAS Youth Interdisciplinary Team and the Shenzhen Science and Technology Innovation Committee[No.JCYJ20180507182241844,JCHZ20200005,DWKF20190009].
文摘Streptomyces has enormous potential to produce novel natural products(NPs)as it harbors a huge reservoir of uncharacterized and silent natural product biosynthetic gene clusters(BGCs).However,the lack of efficient gene cluster engineering strategies has hampered the pace of new drug discovery.Here,we developed an easy-to-use,highly flexible DNA assembly toolkit for gene cluster engineering.The DNA assembly toolkit is compatible with various DNA assembling approaches including Biobrick,Golden Gate,CATCH,yeast homologous recombination-based DNA assembly and homing endonuclease-mediated assembly.This compatibility offers great flexibility in handling multiple genetic parts or refactoring large gene clusters.To demonstrate the utility of this toolkit,we quantified a library of modular regulatory parts,and engineered a gene cluster(act)using characterized promoters that led to increased production.Overall,this work provides a powerful part assembly toolkit that can be used for natural product discovery and optimization in Streptomyces.
