Structure-based virtual screening（molecular docking）is now one of the most pragmatic techniques to leverage target structure for ligand discovery.Accurate binding pose prediction is critical to molecular docking.Her...Structure-based virtual screening（molecular docking）is now one of the most pragmatic techniques to leverage target structure for ligand discovery.Accurate binding pose prediction is critical to molecular docking.Here,we describe a general strategy to improve the accuracy of docking pose prediction by implementing the structural descriptor-based fltering and KGS-penalty function-based conformational clustering in an unbiased manner.We assessed our method against 150 high-quality protein–ligand complex structures.Surprisingly,such simple components are suffcient to improve the accuracy of docking pose prediction.The success rate of predicting near-native docking pose increased from 53%of the targets to 78%.We expect that our strategy may have general usage in improving currently available molecular docking programs.展开更多
Modal analysis,which provides modal parameters including frequencies,damping ratios,and mode shapes,is essential for assessing structural safety in structural health monitoring.Automated operational modal analysis(AOM...Modal analysis,which provides modal parameters including frequencies,damping ratios,and mode shapes,is essential for assessing structural safety in structural health monitoring.Automated operational modal analysis(AOMA)offers a promising alternative to traditional methods that depend heavily on human intervention and engineering judgment.However,estimating structural dynamic properties and managing spurious modes remain challenging due to uncertainties in practical application conditions.To address this issue,we propose an automated modal identification approach comprising three key aspects:(1)identification of modal parameters using covariance-driven stochastic subspace identification;(2)automated interpretation of the stabilization diagram;(3)an improved self-adaptive algorithm for grouping physical modes based on ordering points to identify the clustering structure(OPTICS)combined with k-nearest neighbors(KNN).The proposed approach can play a crucial role in enabling real-time structural health monitoring without human intervention.A simulated 10-story shear frame was used to verify the methodology.Identification results from a cable-stayed bridge demonstrate the practicality of the proposed method for conducting AOMA in engineering practice.The proposed approach can automatically identify modal parameters with high accuracy,making it suitable for a real-time structural health monitoring framework.展开更多
Nucleus is essentially composed of protons and neutrons,which are commonly known as nucleons.Interestingly,some of nucleons may group together and exhibit collective behavior inside a nucleus.Such clustering efects ha...Nucleus is essentially composed of protons and neutrons,which are commonly known as nucleons.Interestingly,some of nucleons may group together and exhibit collective behavior inside a nucleus.Such clustering efects have been known since the early stages of nuclear physics because of the observation and description ofα-cluster decay from many heavy nuclei.Subsequent studies demonstrated that cluster structures exist in many nuclear systems,especially in weakly bound or excited states,and are complementary to the shell-like structures.In this review article,we provide a brief historical recall of the feld,and follow it with a conceptual and logical description of the major theoretical models that have been frequently applied in the literature to describe nuclear clustering.Experimental methods and progress are outlined,recent outcomes are emphasized,and perspectives relevant to future studies of heavy neutron-rich systems are discussed.展开更多
A new mixed-metal sulfido incomplete cubane cluster [(MoCuS3) (O) (μ-dtp) (PPh3)3] Cdtp = S2P (OC2H5)2] has been prepared by reaction of (NH4)2MoOS3 with Cu(dtp) (PPh3)2 in dimethylformamide solution. It crystallizes...A new mixed-metal sulfido incomplete cubane cluster [(MoCuS3) (O) (μ-dtp) (PPh3)3] Cdtp = S2P (OC2H5)2] has been prepared by reaction of (NH4)2MoOS3 with Cu(dtp) (PPh3)2 in dimethylformamide solution. It crystallizes in the triclinic space group P1, a = 13.810(5), b = 19. 753(5), c=11. 719(4) A. α=99. 42(2), β=107. 24(3),γ=88. 05(3)°, V = 3012(2)A3, Dc = l. 51g/cm3and Z = 2. Final R=0. 046, Rw = 0. 056 for 7700 unique intensity data(I≥3σ(I)). The central unit [MoCu3S3]3+ can be described as a distorted incomplete cube with one missing corner. The Mo atom is tetrahedrally coordinated by three μ3-S atoms and one terminal O atom. Two Cu atoms are tetrahedrally coordinated whereas the third Cu atom has a highly distorted trigonal environment. The mean Mo - Cu bond length is 2. 752A. The Cu...Cu distances are in the range of 3. 200(1) -3. 740(1) A which are too long to form bonds.展开更多
The fusion dynamics of ^(6)Li and ^(7)Li projectiles incident on the ^(13)C and ^(12)C targets,respectively,near the Coulomb barrier,were investigated theoretically using the antisymmetrized molecular dynamics(AMD)mod...The fusion dynamics of ^(6)Li and ^(7)Li projectiles incident on the ^(13)C and ^(12)C targets,respectively,near the Coulomb barrier,were investigated theoretically using the antisymmetrized molecular dynamics(AMD)model.Within the AMD framework,the ground-state configurations of ^(6)Li and ^(7)Li exhibit pronounced deformation characterized by well-developed d+α and t+α clustering structures,respectively.Reaction simulations were performed across a center-of-mass energy range of 3−7.6MeV,encompassing the fusion barrier region.The total fusion cross sections computed as a function of collision energy demon-strate favorable quantitative agreement with the experimental values at energies above the Coulomb barrier.Additionally,a detailed comparison was made of the partial cross sections into specific residual fragments predicted by AMD at different center-of-mass energies.The AMD model provides a robust microscopic description of light-heavy-ion fusion dynamics and captures the role of extended density distributions and cluster correlations within interacting nuclei.展开更多
The hydrothermal reaction of 5-methoxyisophthalic acid（MeO-H2ip）, 1,3-bis（2-methylimidazol-1-yl）propane（bmip） and Zn（NO3）2·6H2O in the presence of NaOCH3 gave rise to a three-dimensional（3-D） metal-orga...The hydrothermal reaction of 5-methoxyisophthalic acid（MeO-H2ip）, 1,3-bis（2-methylimidazol-1-yl）propane（bmip） and Zn（NO3）2·6H2O in the presence of NaOCH3 gave rise to a three-dimensional（3-D） metal-organic framework containing octanuclear Zn（II） units, [Zn4（MeO-ip）3（OH）2（bmip）]n. Single-crystal X-ray diffraction analysis reveals that the complex crystallizes in the triclinic space group P1 with a = 11.348（3）, b = 14.163（4）, c = 15.088（4） , α = 108.537（2）, β = 106.542（2）, γ = 103.106（1）o, V = 2065.4（9） -3, Z = 2, Mr = 334.62, Dc = 1.740 g·cm-（-3）, μ = 2.375 mm-（-1）, S = 1.015, F（000） = 1096, the final R = 0.0272 and w R = 0.0715 for 8929 observed reflections（I 〉 2σ（I））. The complex is thermally stable up to 370 oC, and exhibits photoluminescent emission at 450 nm on 350 nm excitation.展开更多
In conjunction with association rules for data mining, the connections between testing indices and strong and weak association rules were determined, and new derivative rules were obtained by further reasoning. Associ...In conjunction with association rules for data mining, the connections between testing indices and strong and weak association rules were determined, and new derivative rules were obtained by further reasoning. Association rules were used to analyze correlation and check consistency between indices. This study shows that the judgment obtained by weak association rules or non-association rules is more accurate and more credible than that obtained by strong association rules. When the testing grades of two indices in the weak association rules are inconsistent, the testing grades of indices are more likely to be erroneous, and the mistakes are often caused by human factors. Clustering data mining technology was used to analyze the reliability of a diagnosis, or to perform health diagnosis directly. Analysis showed that the clustering results are related to the indices selected, and that if the indices selected are more significant, the characteristics of clustering results are also more significant, and the analysis or diagnosis is more credible. The indices and diagnosis analysis function produced by this study provide a necessary theoretical foundation and new ideas for the development of hydraulic metal structure health diagnosis technology.展开更多
The structure and magnetic properties of Osn （n=11～22） clusters are systematically studied by using density functional theory （DFT）. For each size, the average binding energy per atom, the second-order difference...The structure and magnetic properties of Osn （n=11～22） clusters are systematically studied by using density functional theory （DFT）. For each size, the average binding energy per atom, the second-order differences of total energies and the highest occupied molecular orbital （HOMO）–the lowest unoccupied molecular orbital （LUMO） gaps are calculated to analyze the stability of the cluster. The structures of Os14 and Os18 clusters are based on a close-packed hexagonal structure, and they have maximum stabilities, so n=14, 18 are the magic numbers. The 5d electrons play a dominant role in the chemical reaction of Osn clusters. The magnetic moments of Osn clusters are quenched around n=12, and when n=18～22 the value approximates to zero, due to the difference of electron transfer.展开更多
A novel Dy^（3＋） coordination compound,（H_2pipz）（H_3O）[Dy（pydc）_3]·11H_2O（1,pipz = piperazine and H_2pydc = pyridine-2,6-dicarboxylic acid）,has been hydrothermally synthesized and characterized by X-ray...A novel Dy^（3＋） coordination compound,（H_2pipz）（H_3O）[Dy（pydc）_3]·11H_2O（1,pipz = piperazine and H_2pydc = pyridine-2,6-dicarboxylic acid）,has been hydrothermally synthesized and characterized by X-ray single-crystal diffraction,elemental analysis. It is interesting that the packing structure of compound 1 contains 22-core water clusters. Compound 1 is extended into a threedimensional supramolecular structure via O···H···O hydrogen bonding interactions. Furthermore,the luminescent property of compound 1 was also investigated.展开更多
The study of inelastic scattering and multi-nucleon transfer reactions was performed by bombarding a 9Be target with a 3He beam at the incident energy of 30 MeV. Angular distributions for 9Be(3He, 3He) 9Be, 9Be (3He, ...The study of inelastic scattering and multi-nucleon transfer reactions was performed by bombarding a 9Be target with a 3He beam at the incident energy of 30 MeV. Angular distributions for 9Be(3He, 3He) 9Be, 9Be (3He, 3He) 8Be, 9Be (3He, 7Be) 5He, 9Be (3He, 6Li) 6Li and 9Be (3He, 7Li) 5Li reaction channels were measured. Experimental angular distributions for the corresponding ground states (g.s.) were analyzed within the framework of the optical model, the coupled-channel approach and the distorted-wave Born approximation. Cross sections for channels leading to unbound 5Heg.s., 5Lig.s. and 8Be systems were obtained from singles measurements where the relationship between the energy and the scattering angle of the observed stable ejectile was constrained by two-body kinematics. Information on the cluster structure of 9Be was obtained from the transfer channels. It was concluded that cluster transfer was an important mechanism in the investigated nuclear reaction channels. In the present work an attempt was made to estimate the relative strengths of the interesting (n + 8Be) and (α + 5He) cluster configurations in 9Be. The contributions of different exit channels have been determined confirming that the (α + 5He) configuration plays an important role. The configuration of 8Be consisting of two bound helium clusters (5He + 6He) is significantly suppressed, whereas the two-body configurations (n + 8Be) and (α + 5He) including unbound 8Be and 5He are found more probable.展开更多
The structures of Pt clusters on nitrogen-, boron-,silicon- doped graphenes are theoretically studied using densityfunctional theory. These dopants （nitrogen, boron and silicon） each do not induce a local curvature ...The structures of Pt clusters on nitrogen-, boron-,silicon- doped graphenes are theoretically studied using densityfunctional theory. These dopants （nitrogen, boron and silicon） each do not induce a local curvature in the graphene and the doped graphenes all retain their planar form. The formation energy of the silicon-graphene system is lower than those of the nitrogen-, boron-doped graphenes, indicating that the silicon atom is easier to incorporate into the graphene. All the substitutional impurities enhance the interaction between the Pt atom and the graphene. The adsorption energy of a Pt adsorbed on the silicon-doped graphene is much higher than those on the nitrogen-and boron-doped graphenes. The doped silicon atom can provide more charges to enhance the Pt-graphene interaction and the formation of Pt clusters each with a large size. The stable structures of Pt clusters on the doped-graphenes are dimeric, triangle and tetrahedron with the increase of the Pt coverage. Of all the studied structures, the tetrahedron is the most stable cluster which has the least influence on the olanar surface of doned-graohene.展开更多
The sixth Data Release （DR6） of the Sloan Digital Sky Survey （SDSS） provides more photometric regions, new features and more accurate data around globular cluster Palomar 5. A new method, Back Propagation Neural N...The sixth Data Release （DR6） of the Sloan Digital Sky Survey （SDSS） provides more photometric regions, new features and more accurate data around globular cluster Palomar 5. A new method, Back Propagation Neural Network （BPNN）, is used to estimate the cluster membership probability in order to detect its tidal tails. Cluster and field stars, used for training the networks, are extracted over a 40 × 20 deg^2 field by color-magnitude diagrams （CMDs）. The best BPNNs with two hidden layers and a Levenberg-Marquardt （LM） training algorithm are determined by the chosen cluster and field samples. The membership probabilities of stars in the whole field are obtained with the BPNNs, and contour maps of the probability distribution show that a tail extends .5.42° to the north of the cluster and another tail extends 3.77° to the south. The tails are similar to those detected by Odenkirchen et al., but no more debris from the cluster is found to the northeast in the sky. The radial density profiles are investigated both along the tails and near the cluster center. Quite a few substructures are discovered in the tails. The number density profile of the cluster is fitted with the King model and the tidal radius is determined as 14.28＇. However, the King model cannot fit the observed profile at the outer regions （R 〉 8＇） because of the tidal tails generated by the tidal force. Luminosity functions of the cluster and the tidal tails are calculated, which confirm that the tails originate from Palomar 5.展开更多
A tetranuclear copper (I) complex of the ditholate ligand fused with a TTF moiety hasbeen synthesized and characterized crystallographically. This is the first example of a metaJ clustercoordinated with the new type l...A tetranuclear copper (I) complex of the ditholate ligand fused with a TTF moiety hasbeen synthesized and characterized crystallographically. This is the first example of a metaJ clustercoordinated with the new type ligand. The complex shows interesting redox and radical properties.展开更多
The electronic structure of the clusters containing oxygen, the stacking fault and the complex in the transition metal Ni are calculated by the multiple-scattering Xa method. Energy levels,density of states and transf...The electronic structure of the clusters containing oxygen, the stacking fault and the complex in the transition metal Ni are calculated by the multiple-scattering Xa method. Energy levels,density of states and transfer of charge are obtained. Based on the calculation and analysis,the influences of impurity oxygen and structure defect on the electronic structure of the clusters are discussed, and it is found that the local Ni-o cluster with the interstitial oxygen is a stable atomic configuration.展开更多
The Ira （n=1-13） clusters are studied using the relativistic density functional method with generalized gradient approximation. A series of low-lying structures with different spin multiplicities have been considere...The Ira （n=1-13） clusters are studied using the relativistic density functional method with generalized gradient approximation. A series of low-lying structures with different spin multiplicities have been considered. It is found that all the lowest-energy Ira （n=4-13） geometries prefer non-compact structures rather than compact structure growth pattern. And the cube structure is a very stable cell for the lowest-energy Ira （n 〉 8） clusters. The second-order difference of energy, the vertical ionization potentials, the electron affinities and the atomic average magnetic moments for the lowest-energy Ira geometries all show odd even alternative behaviours.展开更多
By use of self-consistent field Xα scattered-wave (SCF-Xα-SW) method, the electronic structure was calculated for four models of Ti4Al14X (X=Al, Fe, Ni and Cu) clusters. The Ti4Al14X cluster was developed based on L...By use of self-consistent field Xα scattered-wave (SCF-Xα-SW) method, the electronic structure was calculated for four models of Ti4Al14X (X=Al, Fe, Ni and Cu) clusters. The Ti4Al14X cluster was developed based on L12 Al3Ti-base intermetallic compound. The results are presented using the density of states (DOS) and one-electron properties, such as relative binding tendency between the atom and the model cluster, and hybrid bonding tendency between the alloying element and the host atoms. By comparing the four models of Ti4Al14X cluster, the effect of the Fe, Ni or Cu atom on the physical properties of Al3Ti-based L12 intermetallic compounds is analyzed. The results indicate that the addition of the Fe, Ni or Cu atom intensifies the relative binding tendency between Ti atom and Ti4Al14X cluster. It was found that the Fermi level (EF) lies in a maximum in the DOS for Ti4Al14Al cluster; on the contrary, the EF comes near a minimum tn the DOS for Ti4Al14X (X=Fe, Ni and Cu) cluster. Thus the L12 crystal structure for binary Al3Ti alloy is unstable, and the addition of the Fe, Ni or Cu atom to Al3Ti is benefical to stabilize L12 crystal structure. The calculation also shows that the Fe, Ni or Cu atom strengthens the hybrid bonding tendency between the central atom and the host atoms for Ti4Al14X cluster and thereby may lead to the constriction of the lattice of Al3Ti-base intermetallic compounds.展开更多
Two new metal-organic frameworks（MOFs）, namely, [Co_2（L_1）（bix）（μ_3-OH）]·2H_2O（1） and [Co_2（L_2）（bix）（μ_3-OH）]·2.5H_2O（2）（H_3L_1 = 5-oxyacetate isophthalic acid, H_3L_2 = 3,5-bis-oxyacet...Two new metal-organic frameworks（MOFs）, namely, [Co_2（L_1）（bix）（μ_3-OH）]·2H_2O（1） and [Co_2（L_2）（bix）（μ_3-OH）]·2.5H_2O（2）（H_3L_1 = 5-oxyacetate isophthalic acid, H_3L_2 = 3,5-bis-oxyacetate-benzoic acid, bix = 1,4-bis（imidazol-1-ylmethyl）benzene）, have been synthesized under hydrothermal conditions. Their structures were determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, IR spectra, and powder X-ray diffraction（PXRD） analysis. Both complexes 1 and 2 demonstrate identical three-dimensional（3D）（3,8）-connected tfz-d nets with（4~3）_2（4~6·6^（18）·8~4） topologies, where the tetranuclear [Co_4（μ_3-OH）_2] clusters act as 8-connected nodes and aromatic multicarboxylic ligands as 3-connected nodes. The results show that the ligands with different geometrical conformations can form products with the same topological structures. Their thermal and magnetic properties were also investigated.展开更多
The cluster compound[Mo_4S_4(μ-O_2CC_5H_5)_2(dtp)_4](dtp=S_2P(OEt)_2)was obtained by the ligand substitution reaction of tetranuclear molybdenum cluster [Mo_4S_4(μ-dtp)_2(dtp)_4]in the mixed solvent of acetone,ethan...The cluster compound[Mo_4S_4(μ-O_2CC_5H_5)_2(dtp)_4](dtp=S_2P(OEt)_2)was obtained by the ligand substitution reaction of tetranuclear molybdenum cluster [Mo_4S_4(μ-dtp)_2(dtp)_4]in the mixed solvent of acetone,ethanol and water in the presence of C_6H_5CO_2Na.It is monoclinic and crystallizes in space group C2/c, Mr=1495.09,a=12.175(5),b=22.01(1),c=20.875(9),β=99.04(4)°;V=5575(5);Z=4; Dc=1.78g/cm^3.Final R factor is 0.066.The result reveals that the[Mo_4S_4]cluster core and t-(dtp)^(-1)ligands are retained and only μ-bridged(dtp)^(-1)ligands are substituted by(C_6H_5CO_2)^(-1)in the substitution reaction,thus producing the new title cluster compound,the structure of which contains two species of bidentate ligand.展开更多
The new cluster[Mo_4(μ_3-O)_2O_4Cl_2(o-CH_3C_6H_4COO)_6]has been prepared by the reaction of molybdenum pentachloride and o-methylbenzoic acid.The crystal and molecular structures were determined by the X-ray diffrac...The new cluster[Mo_4(μ_3-O)_2O_4Cl_2(o-CH_3C_6H_4COO)_6]has been prepared by the reaction of molybdenum pentachloride and o-methylbenzoic acid.The crystal and molecular structures were determined by the X-ray diffraction method.It crystallizes in the orthorhombic space group Pnna with cell parameters:Mr=1361.6,a=13.792(4), b=17.957(3),c=20.974(9) ,V=5194(2) ~3,Z=4,Dc=1.74/cm^3,F(OOO)=2704,μ(MoK ) =11.0/cm,R=0.074.展开更多
Reaction of (NH_4)_2MoS_4 with AgI in α-MePy gives the title com- pound,an X-ray analysis of which shows that the molecule forms a one-dimensional polymeric chain with continuous metal-metal bonds.
文摘Structure-based virtual screening（molecular docking）is now one of the most pragmatic techniques to leverage target structure for ligand discovery.Accurate binding pose prediction is critical to molecular docking.Here,we describe a general strategy to improve the accuracy of docking pose prediction by implementing the structural descriptor-based fltering and KGS-penalty function-based conformational clustering in an unbiased manner.We assessed our method against 150 high-quality protein–ligand complex structures.Surprisingly,such simple components are suffcient to improve the accuracy of docking pose prediction.The success rate of predicting near-native docking pose increased from 53%of the targets to 78%.We expect that our strategy may have general usage in improving currently available molecular docking programs.
基金supported by the National Natural Science Foundation of China(No.52408200)the Natural Science Foundation of Jiangsu Province(No.BK20240996)+1 种基金China,the Suzhou Science and Technology Plan(Basic Research)Project(No.SJC2023002)China,and the Natural Science Research Projects of Colleges and Universities in Jiangsu Province(No.24KJB560022),China.
文摘Modal analysis,which provides modal parameters including frequencies,damping ratios,and mode shapes,is essential for assessing structural safety in structural health monitoring.Automated operational modal analysis(AOMA)offers a promising alternative to traditional methods that depend heavily on human intervention and engineering judgment.However,estimating structural dynamic properties and managing spurious modes remain challenging due to uncertainties in practical application conditions.To address this issue,we propose an automated modal identification approach comprising three key aspects:(1)identification of modal parameters using covariance-driven stochastic subspace identification;(2)automated interpretation of the stabilization diagram;(3)an improved self-adaptive algorithm for grouping physical modes based on ordering points to identify the clustering structure(OPTICS)combined with k-nearest neighbors(KNN).The proposed approach can play a crucial role in enabling real-time structural health monitoring without human intervention.A simulated 10-story shear frame was used to verify the methodology.Identification results from a cable-stayed bridge demonstrate the practicality of the proposed method for conducting AOMA in engineering practice.The proposed approach can automatically identify modal parameters with high accuracy,making it suitable for a real-time structural health monitoring framework.
基金National Key R&D Program of China(Nos.2023YFA1606403,2023YFE0101600,2022YFA1605100,and 2023YFE0101500)National Natural Science Foundation of China(Nos.12027809,11961141003,and 12275006)。
文摘Nucleus is essentially composed of protons and neutrons,which are commonly known as nucleons.Interestingly,some of nucleons may group together and exhibit collective behavior inside a nucleus.Such clustering efects have been known since the early stages of nuclear physics because of the observation and description ofα-cluster decay from many heavy nuclei.Subsequent studies demonstrated that cluster structures exist in many nuclear systems,especially in weakly bound or excited states,and are complementary to the shell-like structures.In this review article,we provide a brief historical recall of the feld,and follow it with a conceptual and logical description of the major theoretical models that have been frequently applied in the literature to describe nuclear clustering.Experimental methods and progress are outlined,recent outcomes are emphasized,and perspectives relevant to future studies of heavy neutron-rich systems are discussed.
文摘A new mixed-metal sulfido incomplete cubane cluster [(MoCuS3) (O) (μ-dtp) (PPh3)3] Cdtp = S2P (OC2H5)2] has been prepared by reaction of (NH4)2MoOS3 with Cu(dtp) (PPh3)2 in dimethylformamide solution. It crystallizes in the triclinic space group P1, a = 13.810(5), b = 19. 753(5), c=11. 719(4) A. α=99. 42(2), β=107. 24(3),γ=88. 05(3)°, V = 3012(2)A3, Dc = l. 51g/cm3and Z = 2. Final R=0. 046, Rw = 0. 056 for 7700 unique intensity data(I≥3σ(I)). The central unit [MoCu3S3]3+ can be described as a distorted incomplete cube with one missing corner. The Mo atom is tetrahedrally coordinated by three μ3-S atoms and one terminal O atom. Two Cu atoms are tetrahedrally coordinated whereas the third Cu atom has a highly distorted trigonal environment. The mean Mo - Cu bond length is 2. 752A. The Cu...Cu distances are in the range of 3. 200(1) -3. 740(1) A which are too long to form bonds.
基金supported by the National Natural Science Foundation of China(Nos.12465024 and 12365018)Natural Science Foundation of Inner Mongolia(Nos.2024ZD23,2024FX30 and 2023MS01005)+1 种基金the program of Innovative Research Team and Young Talents of Science and Technology in Universities of Inner Mongolia Autonomous Region(Nos.NMGIRT2217 and NJYT23109)the Central Government Guidance for Local Science and Technology Development Funds Project(No.2025ZY0067).
文摘The fusion dynamics of ^(6)Li and ^(7)Li projectiles incident on the ^(13)C and ^(12)C targets,respectively,near the Coulomb barrier,were investigated theoretically using the antisymmetrized molecular dynamics(AMD)model.Within the AMD framework,the ground-state configurations of ^(6)Li and ^(7)Li exhibit pronounced deformation characterized by well-developed d+α and t+α clustering structures,respectively.Reaction simulations were performed across a center-of-mass energy range of 3−7.6MeV,encompassing the fusion barrier region.The total fusion cross sections computed as a function of collision energy demon-strate favorable quantitative agreement with the experimental values at energies above the Coulomb barrier.Additionally,a detailed comparison was made of the partial cross sections into specific residual fragments predicted by AMD at different center-of-mass energies.The AMD model provides a robust microscopic description of light-heavy-ion fusion dynamics and captures the role of extended density distributions and cluster correlations within interacting nuclei.
基金supported by the Natural Science Foundation of Fujian Province(2015J01038)Provincial Education Department of Fujian(JA12070)State Key Laboratory of Structural Chemistry(20150015)
文摘The hydrothermal reaction of 5-methoxyisophthalic acid（MeO-H2ip）, 1,3-bis（2-methylimidazol-1-yl）propane（bmip） and Zn（NO3）2·6H2O in the presence of NaOCH3 gave rise to a three-dimensional（3-D） metal-organic framework containing octanuclear Zn（II） units, [Zn4（MeO-ip）3（OH）2（bmip）]n. Single-crystal X-ray diffraction analysis reveals that the complex crystallizes in the triclinic space group P1 with a = 11.348（3）, b = 14.163（4）, c = 15.088（4） , α = 108.537（2）, β = 106.542（2）, γ = 103.106（1）o, V = 2065.4（9） -3, Z = 2, Mr = 334.62, Dc = 1.740 g·cm-（-3）, μ = 2.375 mm-（-1）, S = 1.015, F（000） = 1096, the final R = 0.0272 and w R = 0.0715 for 8929 observed reflections（I 〉 2σ（I））. The complex is thermally stable up to 370 oC, and exhibits photoluminescent emission at 450 nm on 350 nm excitation.
基金supported by the Key Program of the National Natural Science Foundation of China(Grant No.50539010)the Special Fund for Public Welfare Industry of the Ministry of Water Resources of China(Grant No.200801019)
文摘In conjunction with association rules for data mining, the connections between testing indices and strong and weak association rules were determined, and new derivative rules were obtained by further reasoning. Association rules were used to analyze correlation and check consistency between indices. This study shows that the judgment obtained by weak association rules or non-association rules is more accurate and more credible than that obtained by strong association rules. When the testing grades of two indices in the weak association rules are inconsistent, the testing grades of indices are more likely to be erroneous, and the mistakes are often caused by human factors. Clustering data mining technology was used to analyze the reliability of a diagnosis, or to perform health diagnosis directly. Analysis showed that the clustering results are related to the indices selected, and that if the indices selected are more significant, the characteristics of clustering results are also more significant, and the analysis or diagnosis is more credible. The indices and diagnosis analysis function produced by this study provide a necessary theoretical foundation and new ideas for the development of hydraulic metal structure health diagnosis technology.
基金Project supported by the National Natural Science Foundation of China(Grant No.51072072)
文摘The structure and magnetic properties of Osn （n=11～22） clusters are systematically studied by using density functional theory （DFT）. For each size, the average binding energy per atom, the second-order differences of total energies and the highest occupied molecular orbital （HOMO）–the lowest unoccupied molecular orbital （LUMO） gaps are calculated to analyze the stability of the cluster. The structures of Os14 and Os18 clusters are based on a close-packed hexagonal structure, and they have maximum stabilities, so n=14, 18 are the magic numbers. The 5d electrons play a dominant role in the chemical reaction of Osn clusters. The magnetic moments of Osn clusters are quenched around n=12, and when n=18～22 the value approximates to zero, due to the difference of electron transfer.
基金financially supported by the Foundation of Fujian Educational Committee(JA14348)
文摘A novel Dy^（3＋） coordination compound,（H_2pipz）（H_3O）[Dy（pydc）_3]·11H_2O（1,pipz = piperazine and H_2pydc = pyridine-2,6-dicarboxylic acid）,has been hydrothermally synthesized and characterized by X-ray single-crystal diffraction,elemental analysis. It is interesting that the packing structure of compound 1 contains 22-core water clusters. Compound 1 is extended into a threedimensional supramolecular structure via O···H···O hydrogen bonding interactions. Furthermore,the luminescent property of compound 1 was also investigated.
基金supported in part by the Russian Foundation for Basic Research(project numbers:13-02-00533 and 14-02-91053),the CANAM(IPN ASCR)by the grants to JINR(Dubna)from the Czech Republic,the Republic of Poland and the mobility grant from the Academy of Finland.
文摘The study of inelastic scattering and multi-nucleon transfer reactions was performed by bombarding a 9Be target with a 3He beam at the incident energy of 30 MeV. Angular distributions for 9Be(3He, 3He) 9Be, 9Be (3He, 3He) 8Be, 9Be (3He, 7Be) 5He, 9Be (3He, 6Li) 6Li and 9Be (3He, 7Li) 5Li reaction channels were measured. Experimental angular distributions for the corresponding ground states (g.s.) were analyzed within the framework of the optical model, the coupled-channel approach and the distorted-wave Born approximation. Cross sections for channels leading to unbound 5Heg.s., 5Lig.s. and 8Be systems were obtained from singles measurements where the relationship between the energy and the scattering angle of the observed stable ejectile was constrained by two-body kinematics. Information on the cluster structure of 9Be was obtained from the transfer channels. It was concluded that cluster transfer was an important mechanism in the investigated nuclear reaction channels. In the present work an attempt was made to estimate the relative strengths of the interesting (n + 8Be) and (α + 5He) cluster configurations in 9Be. The contributions of different exit channels have been determined confirming that the (α + 5He) configuration plays an important role. The configuration of 8Be consisting of two bound helium clusters (5He + 6He) is significantly suppressed, whereas the two-body configurations (n + 8Be) and (α + 5He) including unbound 8Be and 5He are found more probable.
基金Project supported by the National Natural Science Foundation of China (Grant No. 60476047)the Henan Science and Technology Innovation Talent Support Program,China (Grant No. 2008HASTIT030)the Innovation Scientists and Technicians Troop Construction Projects of Henan Province,China (Grant No. 104200510014)
文摘The structures of Pt clusters on nitrogen-, boron-,silicon- doped graphenes are theoretically studied using densityfunctional theory. These dopants （nitrogen, boron and silicon） each do not induce a local curvature in the graphene and the doped graphenes all retain their planar form. The formation energy of the silicon-graphene system is lower than those of the nitrogen-, boron-doped graphenes, indicating that the silicon atom is easier to incorporate into the graphene. All the substitutional impurities enhance the interaction between the Pt atom and the graphene. The adsorption energy of a Pt adsorbed on the silicon-doped graphene is much higher than those on the nitrogen-and boron-doped graphenes. The doped silicon atom can provide more charges to enhance the Pt-graphene interaction and the formation of Pt clusters each with a large size. The stable structures of Pt clusters on the doped-graphenes are dimeric, triangle and tetrahedron with the increase of the Pt coverage. Of all the studied structures, the tetrahedron is the most stable cluster which has the least influence on the olanar surface of doned-graohene.
基金Supported by the National Natural Science Foundation of China
文摘The sixth Data Release （DR6） of the Sloan Digital Sky Survey （SDSS） provides more photometric regions, new features and more accurate data around globular cluster Palomar 5. A new method, Back Propagation Neural Network （BPNN）, is used to estimate the cluster membership probability in order to detect its tidal tails. Cluster and field stars, used for training the networks, are extracted over a 40 × 20 deg^2 field by color-magnitude diagrams （CMDs）. The best BPNNs with two hidden layers and a Levenberg-Marquardt （LM） training algorithm are determined by the chosen cluster and field samples. The membership probabilities of stars in the whole field are obtained with the BPNNs, and contour maps of the probability distribution show that a tail extends .5.42° to the north of the cluster and another tail extends 3.77° to the south. The tails are similar to those detected by Odenkirchen et al., but no more debris from the cluster is found to the northeast in the sky. The radial density profiles are investigated both along the tails and near the cluster center. Quite a few substructures are discovered in the tails. The number density profile of the cluster is fitted with the King model and the tidal radius is determined as 14.28＇. However, the King model cannot fit the observed profile at the outer regions （R 〉 8＇） because of the tidal tails generated by the tidal force. Luminosity functions of the cluster and the tidal tails are calculated, which confirm that the tails originate from Palomar 5.
文摘A tetranuclear copper (I) complex of the ditholate ligand fused with a TTF moiety hasbeen synthesized and characterized crystallographically. This is the first example of a metaJ clustercoordinated with the new type ligand. The complex shows interesting redox and radical properties.
文摘The electronic structure of the clusters containing oxygen, the stacking fault and the complex in the transition metal Ni are calculated by the multiple-scattering Xa method. Energy levels,density of states and transfer of charge are obtained. Based on the calculation and analysis,the influences of impurity oxygen and structure defect on the electronic structure of the clusters are discussed, and it is found that the local Ni-o cluster with the interstitial oxygen is a stable atomic configuration.
基金Project supported by the National Natural Science Foundation of China for Young Scientists(Grant No.10904123)the National Natural Science Foundation of China(Grant Nos.10774118 and 10974152)the Special Item Foundation of Educational Committee of Shaanxi Province,China(Grant No.08JK471)
文摘The Ira （n=1-13） clusters are studied using the relativistic density functional method with generalized gradient approximation. A series of low-lying structures with different spin multiplicities have been considered. It is found that all the lowest-energy Ira （n=4-13） geometries prefer non-compact structures rather than compact structure growth pattern. And the cube structure is a very stable cell for the lowest-energy Ira （n 〉 8） clusters. The second-order difference of energy, the vertical ionization potentials, the electron affinities and the atomic average magnetic moments for the lowest-energy Ira geometries all show odd even alternative behaviours.
文摘By use of self-consistent field Xα scattered-wave (SCF-Xα-SW) method, the electronic structure was calculated for four models of Ti4Al14X (X=Al, Fe, Ni and Cu) clusters. The Ti4Al14X cluster was developed based on L12 Al3Ti-base intermetallic compound. The results are presented using the density of states (DOS) and one-electron properties, such as relative binding tendency between the atom and the model cluster, and hybrid bonding tendency between the alloying element and the host atoms. By comparing the four models of Ti4Al14X cluster, the effect of the Fe, Ni or Cu atom on the physical properties of Al3Ti-based L12 intermetallic compounds is analyzed. The results indicate that the addition of the Fe, Ni or Cu atom intensifies the relative binding tendency between Ti atom and Ti4Al14X cluster. It was found that the Fermi level (EF) lies in a maximum in the DOS for Ti4Al14Al cluster; on the contrary, the EF comes near a minimum tn the DOS for Ti4Al14X (X=Fe, Ni and Cu) cluster. Thus the L12 crystal structure for binary Al3Ti alloy is unstable, and the addition of the Fe, Ni or Cu atom to Al3Ti is benefical to stabilize L12 crystal structure. The calculation also shows that the Fe, Ni or Cu atom strengthens the hybrid bonding tendency between the central atom and the host atoms for Ti4Al14X cluster and thereby may lead to the constriction of the lattice of Al3Ti-base intermetallic compounds.
基金supported by the application basis research key project of Yunnan Province science and technology department(201401CB00299)the major project of Qujing Normal University(2012ZD002)
文摘Two new metal-organic frameworks（MOFs）, namely, [Co_2（L_1）（bix）（μ_3-OH）]·2H_2O（1） and [Co_2（L_2）（bix）（μ_3-OH）]·2.5H_2O（2）（H_3L_1 = 5-oxyacetate isophthalic acid, H_3L_2 = 3,5-bis-oxyacetate-benzoic acid, bix = 1,4-bis（imidazol-1-ylmethyl）benzene）, have been synthesized under hydrothermal conditions. Their structures were determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, IR spectra, and powder X-ray diffraction（PXRD） analysis. Both complexes 1 and 2 demonstrate identical three-dimensional（3D）（3,8）-connected tfz-d nets with（4~3）_2（4~6·6^（18）·8~4） topologies, where the tetranuclear [Co_4（μ_3-OH）_2] clusters act as 8-connected nodes and aromatic multicarboxylic ligands as 3-connected nodes. The results show that the ligands with different geometrical conformations can form products with the same topological structures. Their thermal and magnetic properties were also investigated.
文摘The cluster compound[Mo_4S_4(μ-O_2CC_5H_5)_2(dtp)_4](dtp=S_2P(OEt)_2)was obtained by the ligand substitution reaction of tetranuclear molybdenum cluster [Mo_4S_4(μ-dtp)_2(dtp)_4]in the mixed solvent of acetone,ethanol and water in the presence of C_6H_5CO_2Na.It is monoclinic and crystallizes in space group C2/c, Mr=1495.09,a=12.175(5),b=22.01(1),c=20.875(9),β=99.04(4)°;V=5575(5);Z=4; Dc=1.78g/cm^3.Final R factor is 0.066.The result reveals that the[Mo_4S_4]cluster core and t-(dtp)^(-1)ligands are retained and only μ-bridged(dtp)^(-1)ligands are substituted by(C_6H_5CO_2)^(-1)in the substitution reaction,thus producing the new title cluster compound,the structure of which contains two species of bidentate ligand.
基金Work supported by the National Natural Science Foundation of China(NNSFC)
文摘The new cluster[Mo_4(μ_3-O)_2O_4Cl_2(o-CH_3C_6H_4COO)_6]has been prepared by the reaction of molybdenum pentachloride and o-methylbenzoic acid.The crystal and molecular structures were determined by the X-ray diffraction method.It crystallizes in the orthorhombic space group Pnna with cell parameters:Mr=1361.6,a=13.792(4), b=17.957(3),c=20.974(9) ,V=5194(2) ~3,Z=4,Dc=1.74/cm^3,F(OOO)=2704,μ(MoK ) =11.0/cm,R=0.074.
文摘Reaction of (NH_4)_2MoS_4 with AgI in α-MePy gives the title com- pound,an X-ray analysis of which shows that the molecule forms a one-dimensional polymeric chain with continuous metal-metal bonds.
