The title complex Mn(H2O)2(HNic)2 (C22H12MnN2O8, Mr = 367.18) crystallizes in monoclinic, space group P21/c with a = 7.5735(8), b = 12.5295(13), c = 7.6466(8)A.β = 101.2790(10)°, Z = 2, V= 711.59...The title complex Mn(H2O)2(HNic)2 (C22H12MnN2O8, Mr = 367.18) crystallizes in monoclinic, space group P21/c with a = 7.5735(8), b = 12.5295(13), c = 7.6466(8)A.β = 101.2790(10)°, Z = 2, V= 711.59(13) A^3, D, = 1.714 g/cm^3,μ(MoKa) = 0.974 mm^-1, F(000) = 374, R1 (1255 observed reflections (Ⅰ 〉 2σ(Ⅰ)) = 0.0250) and wR2 = 0.0662 (all data). In this paper, we report the complexation of Mn(Ⅱ) by the bidentate ligand 2-hydroxynicotinic acid (HNic). In the crystal the Mn(Ⅱ) ion exhibits a deformed octahedron structure. The title complex Mn(H2O)2(HNic)2 has a three-dimensional (3D) network structure extended by hydrogen bonds, which are formed by two typical eight-membered hydrogen-bonded rings.展开更多
Several challenging issues,such as the poor conductivity of sulfur,shuttle effects,large volume change of cathode,and the dendritic lithium in anode,have led to the low utilization of sulfur and hampered the commercia...Several challenging issues,such as the poor conductivity of sulfur,shuttle effects,large volume change of cathode,and the dendritic lithium in anode,have led to the low utilization of sulfur and hampered the commercialization of lithium–sulfur batteries.In this study,a novel three-dimensionally interconnected network structure comprising Co9 S8 and multiwalled carbon nanotubes(MWCNTs)was synthesized by a solvothermal route and used as the sulfur host.The assembled batteries delivered a specific capacity of1154 m Ah g-1 at 0.1 C,and the retention was 64%after 400 cycles at 0.5 C.The polar and catalytic Co9 S8 nanoparticles have a strong adsorbent effect for polysulfide,which can effectively reduce the shuttling effect.Meanwhile,the three-dimensionally interconnected CNT networks improve the overall conductivity and increase the contact with the electrolyte,thus enhancing the transport of electrons and Li ions.Polysulfide adsorption is greatly increased with the synergistic effect of polar Co9 S8 and MWCNTs in the three-dimensionally interconnected composites,which contributes to their promising performance for the lithium–sulfur batteries.展开更多
The title compound (C10H12N2O7, Mr = 272.22) crystallizes in triclinic, space group P1 with a = 5.532(2), b = 9.760(4), c = 11.731(5) ?, α = 68.107(7), β = 89.179(7), γ = 77.830(7)o, V = 573.1(4) ?3, Z = 2, Dc = 1....The title compound (C10H12N2O7, Mr = 272.22) crystallizes in triclinic, space group P1 with a = 5.532(2), b = 9.760(4), c = 11.731(5) ?, α = 68.107(7), β = 89.179(7), γ = 77.830(7)o, V = 573.1(4) ?3, Z = 2, Dc = 1.578 g/cm3, F(000) = 284 and μ(MoKa) = 0.136 mm-1. The final R = 0.0400 and wR = 0.0951 for 1468 observed reflections with I > 2σ(I). The title compound is a 1:1 adduct of sarcosine and 5-nitrosalicylic acid. The nitrogen atom of sarcosine is protonated, and the proton is from the carboxyl group of sarcosine and 5-nitrosalicylic acid with the probability of 50 percent for each. The 5-nitrosalicylic acid and sarcosine molecule of the title adduct are ABAB arranged along the c axis. There exist a lot of hydrogen bonds in the structure, linking sarcosine and 5-nitrosalicylic acid to form a three-dimensional network.展开更多
The crystal structure of the title compound, [enH2][Fe{MoⅤ6O12(OH)3(HPO4)- (H2PO4)3}2]6en6H2O (en = H2NCH2CH2NH2), hydrothermally synthesized from a mixture of Na2MoO42H2O, Fe2(SO4)3, H3PO4, H2N(CH2)2NH2 and water, h...The crystal structure of the title compound, [enH2][Fe{MoⅤ6O12(OH)3(HPO4)- (H2PO4)3}2]6en6H2O (en = H2NCH2CH2NH2), hydrothermally synthesized from a mixture of Na2MoO42H2O, Fe2(SO4)3, H3PO4, H2N(CH2)2NH2 and water, has been determined by single- crystal X-ray diffraction. The crystal is of triclinic, space group P?with a = 11.9014(1), b = 13.4246(2), c = 13.8719(2) , a = 87.465(1), b = 69.981(1), g = 64.960(1)? V = 1873.46(4) 3, Z = 1, Mr = 2997.89, F(000) = 1466, m = 2.427 mm-1 and Dc = 2.657 g/cm3. The final R = 0.0404 for 5570 observed reflections (I > 2s(I)). The structural analysis reveals that each cluster anion contains two coplanar {Mo6} rings of six edge-sharing Mo(O5OH) octahedra, and the two {Mo6} rings are linked together through one octahedral FeⅡ ion to generate a sandwich-type cluster with rigorous () symmetry. Moreover, these clusters are further linked into a three-dimensional frame- work by hydrogen bonds.展开更多
The crystal and molecular structures of O-ethyl-N-(2,3,4-tri-O-acetyl-β-D-xylopyranosyl)-thiocarbamate were determined by X-ray crystallography. It crystallizes in the orthorhombic system with space group P2(1)2(1)2(...The crystal and molecular structures of O-ethyl-N-(2,3,4-tri-O-acetyl-β-D-xylopyranosyl)-thiocarbamate were determined by X-ray crystallography. It crystallizes in the orthorhombic system with space group P2(1)2(1)2(1), lattice parameters a=0.90636(18) nm, b=0.94716(19) nm, c=2.1855(4) nm, V=1.8762(7) nm 3, and Z=4. All the substituents are in equatorial positions. There are four intramolecular interactions, each forming a five-membered ring. The molecules are linked by interactions to form three-dimensional framework. Atoms O6 and O8 show positional disorder.展开更多
Design and fabrication of the micro/nanostructures of the network units is a critical issue for porous nanonetwork structured materials. Significant progress has been attained in construction of the network units with...Design and fabrication of the micro/nanostructures of the network units is a critical issue for porous nanonetwork structured materials. Significant progress has been attained in construction of the network units with zero-dimensional spherical shapes.However, owing to the limitations of synthetic methods, construction of porous building blocks in one dimension featuring high aspect ratios for porous nanonetwork structured polymer(PNSP) remains largely unexplored. Here we present the successful design and preparation of PNSP with a novel type of one-dimensional network unit, i.e., microporous heterogeneous nanowire. Well-defined core-shell polymer nanoobjects prepared from a gelable block copolymer, poly(3-(triethoxysilyl)propyl methacrylate)-block-polystyrene are employed as building blocks, and facilely transformed into PNSP via hypercrosslinking of polystyrene shell. The as-prepared PNSP exhibits unique three-dimensional hierarchical nanonetwork morphologies with large surface area. These findings could provide a new avenue for fabrication of unique well-defined PNSP, and thus generate valuable breakthroughs in many applications.展开更多
Background There have been no detailed reports of the three-dimensional structure and the relationship between the external and internal vascularizations observed successively for a long duration in the rat fetus, alt...Background There have been no detailed reports of the three-dimensional structure and the relationship between the external and internal vascularizations observed successively for a long duration in the rat fetus, although many authors have studied the vascular morphology of the developing brain. This study examined the three-dimensional structure of both the external and internal vascularizations of the prenatal rat telencephalon from embryonic days 12 (E12) to 20 (E20).Method A microvascular casting method for scanning electron microscopy (SEM) was used in this study, along with vascular staining using gold-gelatine solution-autometallography (GGS-AMG) after intravascular injection of colloidal gold, as well as hematoxylin-eosin ( HE) staining for paraffin embedded specimens.Results In GGS-AMG stains, E16 fetuses had a few short perforating cortical blood vessels (SPCVs); E17 fetuses had long perforating cortico-medullary vessels (LPCVs). Older fetuses had specific patterns of vascular networks in the cortex and the deeper subcortical part of the telencephalon. In the cortex, fine longitudinal blood vessels were connected by transverse channels. The deep telencephalon had fine blood vessels running in all directions. Using SEM, the external vascularization was already visible in E12 fetuses as arborizations of arterial branches, forming a mesh of fine vascular networks covering the telencephalon. A coralliform fine venous plexus was observed in the external vascularization of E16 fetuses. There were ring-like anastomoses and bud-like protrusions in the network of small blood vessels, most likely the angiogenesis of fetal vessels. From E12 to E16, an immature and incomplete internal vascularization began to appear. There were short blood vessels with ballooned terminals branching from the external vascularization. They penetrated the brain tissue to form networks in the superficial layer, comparable to SPCVs. In E17 to E20 fetuses, tortuous venous branches, straight arterial blood vessels, and a fine network of small blood vessels formed the external vascularization. There were fewer arterial than venous branches connecting to the fine networks of small blood vessels. LPCVs were noted at E17, at the time the white matter emerged. They branched from the external vascularization, and perpendicularly penetrated the brain surface, traversing the cortical plate, and entering into the deep brain. At E17, arterial and venous blood vessels could be clearly distinguished in the external vascularization. At E20, the cortex and white matter contained specific arrangements of networks of fine blood vessels, as seen by GGS-AMG staining.Conclusion These findings show that the development of both the external and internalvascularization follows the development of thetelencephalon. In particular, the emergence ofthe cortical plate and white matter on E16 andE17 influence the development of both theinternal and the external vascularization. Thelaminal arrangement of blood vessels was notobserved corresponding to the respective laminalneuronal layers.展开更多
Easy fabrication of super-stretchable electrodes can pave the way for smart and wearable electronics.Using drop casting unidirectional nickel nanowires with polyurethane matrix,we fabricated a super-stretchable film w...Easy fabrication of super-stretchable electrodes can pave the way for smart and wearable electronics.Using drop casting unidirectional nickel nanowires with polyurethane matrix,we fabricated a super-stretchable film with high electric conductivity.The as-fabricated film can withstand a 300%tensile strain in the direction perpendicular to nanowires,owing to the transformation of percolating nanowire network from 2D to 3D.In contrast to the decreased film conductivities under large tension in most stretchable electrodes,which usually associate with fractures and irreversible deformations,our film conductivity can increase with the applied strain.This probably benefits from the enhanced electrical contacts between twisted nanowires under tension.The developed super-stretchable film with unprecedented behavior in this work sheds light on the facile fabrication of super-stretchable electrodes with durable performance.展开更多
Thermally stable nano-size ceramic particles are the preferred reinforcements for superalloys as they improve the alloys'microstructural stability and high-temperature properties.In this work,very dense and crack-...Thermally stable nano-size ceramic particles are the preferred reinforcements for superalloys as they improve the alloys'microstructural stability and high-temperature properties.In this work,very dense and crack-free carbidereinforced GTD222(nickel-based superalloy)composites were prepared via selective laser melting(SLM).The distribution of TiC nanoparticles presents a three-dimensional(3D)network structure in the SLMed TiC/GTD222 composite.Mechanical testing revealed that the SLMed TiC/GTD222 composite has superior strength(UTS?1320 MPa,YS?1100 MPa)compared to the SLMed GTD222 superalloy.The GTD22 alloy reinforced with carbide nanoparticles’distinctive microstructure and its excellent mechanical properties for is discussed.展开更多
The reaction of an aqueous solution of sodium molybdate with iron powder at low pH (~0.184) gives rise to the formation of a six-member Mo ring-shape cluster with an Fe (II) encapsulated at the center, [Na4(H2O)7][Fe...The reaction of an aqueous solution of sodium molybdate with iron powder at low pH (~0.184) gives rise to the formation of a six-member Mo ring-shape cluster with an Fe (II) encapsulated at the center, [Na4(H2O)7][Fe(OH)6Mo6O18](1), which is further linked to a remarkable three-dimensional network via sodium ions.展开更多
In an attempt to synthesize a new pyrimidine complex of copper(II) in a solution reaction of CuBr2 with 2,2'-bis(hexahydropyrimidine) and hydro-chloric acid, we unexpectedly obtained a bright yellow chip-like crys...In an attempt to synthesize a new pyrimidine complex of copper(II) in a solution reaction of CuBr2 with 2,2'-bis(hexahydropyrimidine) and hydro-chloric acid, we unexpectedly obtained a bright yellow chip-like crystal of CuCl4(H2tn) [H2tn=(H3NCH2CH2CH2NH3)2+]. Its structure was determined by single-crystal X-ray diffraction analysis. The crystal belongs to orthorhombic system, space group Pnma, with cell parameters: a=0.7216(2) nm, b=1.8308(6) nm, c=0.7553(3) nm, V=0.9953(6) nm3, Z=4, F(000)=564, Mr=281.49, Dc=1.879 g/cm3. (Mo Ka)=3.204 mm-1, R1=0.0248, wR2=0.0575. The analysis of the crystal structure indicates that the complex has a three-dimensional network structure, which is formed by hydrogen bonds and electrostatic interaction.展开更多
A novel La(Ⅲ)-Cu(Ⅱ)heterometallic coordination polymer {[LaCu2(NTA)2(4,4'-bpy)(H2O)3]NO3 5H2O}n,where H3NTA denotes nitrilotriacetic acid and 4,4'-bpy denotes 4,4'-bipyridine,was synthesized and characte...A novel La(Ⅲ)-Cu(Ⅱ)heterometallic coordination polymer {[LaCu2(NTA)2(4,4'-bpy)(H2O)3]NO3 5H2O}n,where H3NTA denotes nitrilotriacetic acid and 4,4'-bpy denotes 4,4'-bipyridine,was synthesized and characterized by IR spectrum,elemental analysis and X-ray diffraction.The complex crystallizes in the triclnic space group PT with cell parameters a=1.33710(10)nm,b=1.44530(10)nm,c=1.0949(2)nm,α=71.905(7),β=74.327(7),γ=64.427(9),V=1.7912(4)nm3 and Z=2.It consists of heterometallic units,in which each La(Ⅲ)ion is coordinated in a distorted mono-capped square antiprism by three oxygen atoms from water molecules and six carboxyl oxygen atoms from five NTA3-ions,and each Cu(Ⅱ)ion is coordinated by one nitrogen atom from 4,4'-bpy and one nitrogen atom,three oxygen atoms from NTA3-.In the title complex,La(Ⅲ)ions and Cu(Ⅱ)ions are connected by the heterometallic bridging of NTA3-,constructing a two-dimensional network structure along the [110].And it is extended into an infinite three-dimensional network structure by the formation of homometallic bridging of Cu-4,4'-bpy-Cu,exhibiting a certain inclusion ability.展开更多
Trees are spread worldwide,as the watchmen that experience the intricate ecological effects caused by various environmental factors.In order to better understand such effects,it is preferential to achieve finely and f...Trees are spread worldwide,as the watchmen that experience the intricate ecological effects caused by various environmental factors.In order to better understand such effects,it is preferential to achieve finely and fully mapped global trees and their environments.For this task,aerial and satellite-based remote sensing(RS)methods have been developed.However,a critical branch regarding the apparent forms of trees has significantly fallen behind due to the technical deficiency found within their globalscale surveying methods.Now,terrestrial laser scanning(TLS),a state-of-the-art RS technology,is useful for the in situ three-dimensional(3D)mapping of trees and their environments.Thus,we proposed co-developing an international TLS network as a macroscale ecotechnology to increase the 3D ecological understanding of global trees.First,we generated the system architecture and tested the available RS models to deepen its ground stakes.Then,we verified the ecotechnology regarding the identification of its theoretical feasibility,a review of its technical preparations,and a case testification based on a prototype we designed.Next,we conducted its functional prospects by previewing its scientific and technical potentials and its functional extensibility.Finally,we summarized its technical and scientific challenges,which can be used as the cutting points to promote the improvement of this technology in future studies.Overall,with the implication of establishing a novel cornerstone-sense ecotechnology,the co-development of an international TLS network can revolutionize the 3D ecological understanding of global trees and create new fields of research from 3D global tree structural ecology to 3D macroecology.展开更多
Stretchable electronics are in high demand for next-generation wearable devices, but their fabrication is still challenging. Stretchable conductors, flexible pressure sensors, and foldable light-emitting diodes (LEDs...Stretchable electronics are in high demand for next-generation wearable devices, but their fabrication is still challenging. Stretchable conductors, flexible pressure sensors, and foldable light-emitting diodes (LEDs) have been reported; however, the fabrication of stable stretchable batteries, as power suppliers for wearable devices, is significantly behind the development of other stretchable electronics. Several stretchable lithium-ion batteries and primary batteries have been fabricated, but their low capacities and complicated manufacturing processes are obstacles for practical applications. Herein, we report a stretchable zinc/manganese-oxide (Zn-MnO2) full battery based on a silver-nanowire- coated sponge prepared via a facile dip-coating process. The spongy electrode, with a three-dimensional (3D) binary network structure, provided not only high conductivity and stretchability, but also enabled a high mass loading of electrochemically active materials (Zn and MnO2 particles). The fabricated Zn-MnO2 battery exhibited an areal capacity as high as 3.6 mAh·cm^-2 and could accommodate tensile strains of up to 100% while retaining 89% of its original capacity. The facile solution-based strategy of dip-coating active materials onto a cheap sponge-based stretchable current collector opens up a new avenue for fabricating stretchable batteries.展开更多
The elastic conductor is crucial in wearable electronics and soft robotics.The ideal intrinsic elastic bulk conductors show uniform three-dimensional conductive networks and stable resistance during large stretch.A ch...The elastic conductor is crucial in wearable electronics and soft robotics.The ideal intrinsic elastic bulk conductors show uniform three-dimensional conductive networks and stable resistance during large stretch.A challenge is that the variation of resistance is high under deformation due to disconnection of conductive pathway for bulk elastic conductors.Our strategy is to introduce buckled structure into the conductive network,by self-assembly of a carbon nanotube layer on the interconnecting micropore surface of a prestrained foam,followed by strain relaxation.Both unfolding of buckles and flattening of micropores contributed to the stability of the resistance under deformation(2.0%resistance variation under 70%strain).Microstructural analysis and finite element analysis illustrated different patterns of two-dimensional buckling structures could be obtained due to the imperfections in the conductive layer.Applications as all-directional interconnects,stretchable electromagnetic interference shielding and electrothermal tumor ablation were demonstrated.展开更多
锂硫电池因其能量密度高、成本低等优势被认为是最具希望的下一代储能器件之一,然而其正极材料的发展和应用仍面临诸多挑战.本文通过将剥离的Ti_(3)C_(2)纳米片在NaOH溶液中刻蚀得到具有交联结构的Ti_(3)C_(2)纳米线,并利用熔融浸渍法...锂硫电池因其能量密度高、成本低等优势被认为是最具希望的下一代储能器件之一,然而其正极材料的发展和应用仍面临诸多挑战.本文通过将剥离的Ti_(3)C_(2)纳米片在NaOH溶液中刻蚀得到具有交联结构的Ti_(3)C_(2)纳米线,并利用熔融浸渍法负载硫颗粒,用作锂硫电池的正极材料.具有极性表面的Ti_(3)C_(2)可有效捕获多硫化锂中间体,从而抑制多硫化锂的穿梭效应.与Ti_(3)C_(2)纳米片相比,具有交联网络状结构的Ti_(3)C_(2)纳米线具有更大的比表面积和多孔结构,可以有效提供固硫所需的空间,并容纳硫在锂化过程中的体积膨胀.其较大的比表面积有利于Ti_(3)C_(2)纳米线对多硫化锂的捕获,其多孔结构有利于锂离子的扩散.Ti_(3)C_(2)纳米线/硫复合物展现出优异的电化学性能,在0.2 C的倍率下,100次循环后,其可逆容量为658 mAh g^(−1);在1 C倍率下,300次循环后,Ti_(3)C_(2)纳米线/硫复合物仍能保持436 mAh g^(−1)的可逆容量.展开更多
High-performance nanogrease manufactured from carbon nanomaterials is observed to be stable and homogeneous and have superb physical properties,such as thermal and electrical conductivities,compared with current comme...High-performance nanogrease manufactured from carbon nanomaterials is observed to be stable and homogeneous and have superb physical properties,such as thermal and electrical conductivities,compared with current commercial greases made of lithium,calcium,and aluminum.For the first time,carbon nanomaterials have been observed to disperse well as the sole thickeners in oil systems,e.g.,polyalphaolefin and polyester(ROYCO),without the aid of any chemical surfactants.Three-dimensional percolation network structures that exist among carbon nanomaterials are easily scalable,which can be attributed to the intermolecular van der Waals forces.Moreover,the introduction of hydrogen bonding in any form to grease significantly increases its thermal and electrical conductivities and substantially reduces the weight percentage of carbon nanomaterials needed to fabricate stable grease.For example,loading of only 1.4 wt%hydroxyl-functionalized multiwalled carbon nanotube(MWNT-OH)with Krytox XHT750 oil leads to a 37.8%increase in thermal conductivity.Moreover,75%glycerol,25% water,and 4.5 wt% MWNT-OH yielded the lowest electrical resistivity of 10.0 Ω cm.This finding can be extended to hydrogen bonding materials with functional groups,such as OH,COOH,F,and NH.The nanogrease reported in this study has been manufactured using the three-roll mill method,which is an easy and cost-effective method,as the loading weight percentage of carbon nanomaterials to fabricate stable grease decreases from 12 wt% to 3-4 wt%.Furthermore,the process is easily scalable,reproduced,and optimized.This novel high-performance nanogrease has a high commercial value and numerous applications and could replace current commercial greases.展开更多
基金This work was supported by the National Natural Science Foundation of China (No. 50572040)
文摘The title complex Mn(H2O)2(HNic)2 (C22H12MnN2O8, Mr = 367.18) crystallizes in monoclinic, space group P21/c with a = 7.5735(8), b = 12.5295(13), c = 7.6466(8)A.β = 101.2790(10)°, Z = 2, V= 711.59(13) A^3, D, = 1.714 g/cm^3,μ(MoKa) = 0.974 mm^-1, F(000) = 374, R1 (1255 observed reflections (Ⅰ 〉 2σ(Ⅰ)) = 0.0250) and wR2 = 0.0662 (all data). In this paper, we report the complexation of Mn(Ⅱ) by the bidentate ligand 2-hydroxynicotinic acid (HNic). In the crystal the Mn(Ⅱ) ion exhibits a deformed octahedron structure. The title complex Mn(H2O)2(HNic)2 has a three-dimensional (3D) network structure extended by hydrogen bonds, which are formed by two typical eight-membered hydrogen-bonded rings.
基金National Natural Science Foundation of China(No.51974209)the Natural Science Foundation of Hubei Province of China(Nos.2013CFA021,2017CFB401,2018CFA022)。
文摘Several challenging issues,such as the poor conductivity of sulfur,shuttle effects,large volume change of cathode,and the dendritic lithium in anode,have led to the low utilization of sulfur and hampered the commercialization of lithium–sulfur batteries.In this study,a novel three-dimensionally interconnected network structure comprising Co9 S8 and multiwalled carbon nanotubes(MWCNTs)was synthesized by a solvothermal route and used as the sulfur host.The assembled batteries delivered a specific capacity of1154 m Ah g-1 at 0.1 C,and the retention was 64%after 400 cycles at 0.5 C.The polar and catalytic Co9 S8 nanoparticles have a strong adsorbent effect for polysulfide,which can effectively reduce the shuttling effect.Meanwhile,the three-dimensionally interconnected CNT networks improve the overall conductivity and increase the contact with the electrolyte,thus enhancing the transport of electrons and Li ions.Polysulfide adsorption is greatly increased with the synergistic effect of polar Co9 S8 and MWCNTs in the three-dimensionally interconnected composites,which contributes to their promising performance for the lithium–sulfur batteries.
文摘The title compound (C10H12N2O7, Mr = 272.22) crystallizes in triclinic, space group P1 with a = 5.532(2), b = 9.760(4), c = 11.731(5) ?, α = 68.107(7), β = 89.179(7), γ = 77.830(7)o, V = 573.1(4) ?3, Z = 2, Dc = 1.578 g/cm3, F(000) = 284 and μ(MoKa) = 0.136 mm-1. The final R = 0.0400 and wR = 0.0951 for 1468 observed reflections with I > 2σ(I). The title compound is a 1:1 adduct of sarcosine and 5-nitrosalicylic acid. The nitrogen atom of sarcosine is protonated, and the proton is from the carboxyl group of sarcosine and 5-nitrosalicylic acid with the probability of 50 percent for each. The 5-nitrosalicylic acid and sarcosine molecule of the title adduct are ABAB arranged along the c axis. There exist a lot of hydrogen bonds in the structure, linking sarcosine and 5-nitrosalicylic acid to form a three-dimensional network.
基金This work was supported by the State Key Laboratory of Structural Chemistry (030065) the Chinese Academy of Sciences the NNSFC (20073048) and the NSF of Fujian province (2002F015)
文摘The crystal structure of the title compound, [enH2][Fe{MoⅤ6O12(OH)3(HPO4)- (H2PO4)3}2]6en6H2O (en = H2NCH2CH2NH2), hydrothermally synthesized from a mixture of Na2MoO42H2O, Fe2(SO4)3, H3PO4, H2N(CH2)2NH2 and water, has been determined by single- crystal X-ray diffraction. The crystal is of triclinic, space group P?with a = 11.9014(1), b = 13.4246(2), c = 13.8719(2) , a = 87.465(1), b = 69.981(1), g = 64.960(1)? V = 1873.46(4) 3, Z = 1, Mr = 2997.89, F(000) = 1466, m = 2.427 mm-1 and Dc = 2.657 g/cm3. The final R = 0.0404 for 5570 observed reflections (I > 2s(I)). The structural analysis reveals that each cluster anion contains two coplanar {Mo6} rings of six edge-sharing Mo(O5OH) octahedra, and the two {Mo6} rings are linked together through one octahedral FeⅡ ion to generate a sandwich-type cluster with rigorous () symmetry. Moreover, these clusters are further linked into a three-dimensional frame- work by hydrogen bonds.
文摘The crystal and molecular structures of O-ethyl-N-(2,3,4-tri-O-acetyl-β-D-xylopyranosyl)-thiocarbamate were determined by X-ray crystallography. It crystallizes in the orthorhombic system with space group P2(1)2(1)2(1), lattice parameters a=0.90636(18) nm, b=0.94716(19) nm, c=2.1855(4) nm, V=1.8762(7) nm 3, and Z=4. All the substituents are in equatorial positions. There are four intramolecular interactions, each forming a five-membered ring. The molecules are linked by interactions to form three-dimensional framework. Atoms O6 and O8 show positional disorder.
基金supported by the National Natural Science Foundation of China(51422307,51372280,51232005)National Program for Support of Top-notch Young Professionals,Guangdong Natural Science Funds for Distinguished Young Scholar(S2013050014408),Tip-top Scientific and Technical Innovative Youth Talents of Guangdong Special Support Program(2014TQ01C337)+1 种基金Fundamental Research Funds for the Central Universities(15lgjc17)National Key Basic Research Program of China(2014CB932400)
文摘Design and fabrication of the micro/nanostructures of the network units is a critical issue for porous nanonetwork structured materials. Significant progress has been attained in construction of the network units with zero-dimensional spherical shapes.However, owing to the limitations of synthetic methods, construction of porous building blocks in one dimension featuring high aspect ratios for porous nanonetwork structured polymer(PNSP) remains largely unexplored. Here we present the successful design and preparation of PNSP with a novel type of one-dimensional network unit, i.e., microporous heterogeneous nanowire. Well-defined core-shell polymer nanoobjects prepared from a gelable block copolymer, poly(3-(triethoxysilyl)propyl methacrylate)-block-polystyrene are employed as building blocks, and facilely transformed into PNSP via hypercrosslinking of polystyrene shell. The as-prepared PNSP exhibits unique three-dimensional hierarchical nanonetwork morphologies with large surface area. These findings could provide a new avenue for fabrication of unique well-defined PNSP, and thus generate valuable breakthroughs in many applications.
文摘Background There have been no detailed reports of the three-dimensional structure and the relationship between the external and internal vascularizations observed successively for a long duration in the rat fetus, although many authors have studied the vascular morphology of the developing brain. This study examined the three-dimensional structure of both the external and internal vascularizations of the prenatal rat telencephalon from embryonic days 12 (E12) to 20 (E20).Method A microvascular casting method for scanning electron microscopy (SEM) was used in this study, along with vascular staining using gold-gelatine solution-autometallography (GGS-AMG) after intravascular injection of colloidal gold, as well as hematoxylin-eosin ( HE) staining for paraffin embedded specimens.Results In GGS-AMG stains, E16 fetuses had a few short perforating cortical blood vessels (SPCVs); E17 fetuses had long perforating cortico-medullary vessels (LPCVs). Older fetuses had specific patterns of vascular networks in the cortex and the deeper subcortical part of the telencephalon. In the cortex, fine longitudinal blood vessels were connected by transverse channels. The deep telencephalon had fine blood vessels running in all directions. Using SEM, the external vascularization was already visible in E12 fetuses as arborizations of arterial branches, forming a mesh of fine vascular networks covering the telencephalon. A coralliform fine venous plexus was observed in the external vascularization of E16 fetuses. There were ring-like anastomoses and bud-like protrusions in the network of small blood vessels, most likely the angiogenesis of fetal vessels. From E12 to E16, an immature and incomplete internal vascularization began to appear. There were short blood vessels with ballooned terminals branching from the external vascularization. They penetrated the brain tissue to form networks in the superficial layer, comparable to SPCVs. In E17 to E20 fetuses, tortuous venous branches, straight arterial blood vessels, and a fine network of small blood vessels formed the external vascularization. There were fewer arterial than venous branches connecting to the fine networks of small blood vessels. LPCVs were noted at E17, at the time the white matter emerged. They branched from the external vascularization, and perpendicularly penetrated the brain surface, traversing the cortical plate, and entering into the deep brain. At E17, arterial and venous blood vessels could be clearly distinguished in the external vascularization. At E20, the cortex and white matter contained specific arrangements of networks of fine blood vessels, as seen by GGS-AMG staining.Conclusion These findings show that the development of both the external and internalvascularization follows the development of thetelencephalon. In particular, the emergence ofthe cortical plate and white matter on E16 andE17 influence the development of both theinternal and the external vascularization. Thelaminal arrangement of blood vessels was notobserved corresponding to the respective laminalneuronal layers.
基金the National Key Research and Development Program of China(Grant No.2019YFA0705400)National Natural Science Foundation of China(Grant Nos.51535005,51472117,51702159)+4 种基金the Research Fund of State Key Laboratory of Mechanics and Control of Mechanical Structures(Grant Nos.MCMS-I-0418K01,MCMS-I-0419K01)the Fundamental Research Funds for the Central Universities(Grant Nos.NC2018001,NP2019301,NJ2019002)Natural Science Foundation of Jiangsu Province(Grant Nos.BK20170791,BK20180416)National and Jiangsu Postdoctoral Research Funds(Grant Nos.2017M610328,2018T110494 and 1701141B)A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘Easy fabrication of super-stretchable electrodes can pave the way for smart and wearable electronics.Using drop casting unidirectional nickel nanowires with polyurethane matrix,we fabricated a super-stretchable film with high electric conductivity.The as-fabricated film can withstand a 300%tensile strain in the direction perpendicular to nanowires,owing to the transformation of percolating nanowire network from 2D to 3D.In contrast to the decreased film conductivities under large tension in most stretchable electrodes,which usually associate with fractures and irreversible deformations,our film conductivity can increase with the applied strain.This probably benefits from the enhanced electrical contacts between twisted nanowires under tension.The developed super-stretchable film with unprecedented behavior in this work sheds light on the facile fabrication of super-stretchable electrodes with durable performance.
基金The authors grateful acknowledge the financial support of the National Natural Science Foundation of China under Projects No.51871147 and 51704195the China Postdoctoral Science Foundation under Project No.19Z102060057+2 种基金the National Science and Technology Major Project under Project No.2017-VI-0013-0085the Science Fund for Creative Research Groups of the National Natural Science Foundation of China under Project No.51821001the Aviation Power Fund under Project No.6141B090324.
文摘Thermally stable nano-size ceramic particles are the preferred reinforcements for superalloys as they improve the alloys'microstructural stability and high-temperature properties.In this work,very dense and crack-free carbidereinforced GTD222(nickel-based superalloy)composites were prepared via selective laser melting(SLM).The distribution of TiC nanoparticles presents a three-dimensional(3D)network structure in the SLMed TiC/GTD222 composite.Mechanical testing revealed that the SLMed TiC/GTD222 composite has superior strength(UTS?1320 MPa,YS?1100 MPa)compared to the SLMed GTD222 superalloy.The GTD22 alloy reinforced with carbide nanoparticles’distinctive microstructure and its excellent mechanical properties for is discussed.
基金the State Key Lab. of Structural Chemistry, the Chinese Academy of Sciences and the State Personnel Ministry.
文摘The reaction of an aqueous solution of sodium molybdate with iron powder at low pH (~0.184) gives rise to the formation of a six-member Mo ring-shape cluster with an Fe (II) encapsulated at the center, [Na4(H2O)7][Fe(OH)6Mo6O18](1), which is further linked to a remarkable three-dimensional network via sodium ions.
基金the National Natural Science Foundation of China (No. 20371039),the Major State Basic Research Program (the 973 Program, No. 2003CB214606), and the Key Laboratory Research and Establishment Program of Shaanxi Education Section (
文摘In an attempt to synthesize a new pyrimidine complex of copper(II) in a solution reaction of CuBr2 with 2,2'-bis(hexahydropyrimidine) and hydro-chloric acid, we unexpectedly obtained a bright yellow chip-like crystal of CuCl4(H2tn) [H2tn=(H3NCH2CH2CH2NH3)2+]. Its structure was determined by single-crystal X-ray diffraction analysis. The crystal belongs to orthorhombic system, space group Pnma, with cell parameters: a=0.7216(2) nm, b=1.8308(6) nm, c=0.7553(3) nm, V=0.9953(6) nm3, Z=4, F(000)=564, Mr=281.49, Dc=1.879 g/cm3. (Mo Ka)=3.204 mm-1, R1=0.0248, wR2=0.0575. The analysis of the crystal structure indicates that the complex has a three-dimensional network structure, which is formed by hydrogen bonds and electrostatic interaction.
基金Project supported by the National Natural Science Foundation of China (No. 29761002)the Ten, Hundred or Thousand Distinguished Person Foundation of Guangxi, China
文摘A novel La(Ⅲ)-Cu(Ⅱ)heterometallic coordination polymer {[LaCu2(NTA)2(4,4'-bpy)(H2O)3]NO3 5H2O}n,where H3NTA denotes nitrilotriacetic acid and 4,4'-bpy denotes 4,4'-bipyridine,was synthesized and characterized by IR spectrum,elemental analysis and X-ray diffraction.The complex crystallizes in the triclnic space group PT with cell parameters a=1.33710(10)nm,b=1.44530(10)nm,c=1.0949(2)nm,α=71.905(7),β=74.327(7),γ=64.427(9),V=1.7912(4)nm3 and Z=2.It consists of heterometallic units,in which each La(Ⅲ)ion is coordinated in a distorted mono-capped square antiprism by three oxygen atoms from water molecules and six carboxyl oxygen atoms from five NTA3-ions,and each Cu(Ⅱ)ion is coordinated by one nitrogen atom from 4,4'-bpy and one nitrogen atom,three oxygen atoms from NTA3-.In the title complex,La(Ⅲ)ions and Cu(Ⅱ)ions are connected by the heterometallic bridging of NTA3-,constructing a two-dimensional network structure along the [110].And it is extended into an infinite three-dimensional network structure by the formation of homometallic bridging of Cu-4,4'-bpy-Cu,exhibiting a certain inclusion ability.
基金The work was financially supported by the National Key Research and Development Program of China(No.2022YFE0112700)the National Natural Science Foundation of China(No.32171782 and 31870531).
文摘Trees are spread worldwide,as the watchmen that experience the intricate ecological effects caused by various environmental factors.In order to better understand such effects,it is preferential to achieve finely and fully mapped global trees and their environments.For this task,aerial and satellite-based remote sensing(RS)methods have been developed.However,a critical branch regarding the apparent forms of trees has significantly fallen behind due to the technical deficiency found within their globalscale surveying methods.Now,terrestrial laser scanning(TLS),a state-of-the-art RS technology,is useful for the in situ three-dimensional(3D)mapping of trees and their environments.Thus,we proposed co-developing an international TLS network as a macroscale ecotechnology to increase the 3D ecological understanding of global trees.First,we generated the system architecture and tested the available RS models to deepen its ground stakes.Then,we verified the ecotechnology regarding the identification of its theoretical feasibility,a review of its technical preparations,and a case testification based on a prototype we designed.Next,we conducted its functional prospects by previewing its scientific and technical potentials and its functional extensibility.Finally,we summarized its technical and scientific challenges,which can be used as the cutting points to promote the improvement of this technology in future studies.Overall,with the implication of establishing a novel cornerstone-sense ecotechnology,the co-development of an international TLS network can revolutionize the 3D ecological understanding of global trees and create new fields of research from 3D global tree structural ecology to 3D macroecology.
基金We acknowledge the funding support from the National Natural Science Foundation of China (Nos. 21431006 and 21761132008), the Foundation for Innovative Research Groups of the National Natural Science Foundation of China (No. 21521001), Key Research Program of Frontier Sciences, CAS (No. QYZDJ-SSW- SLH036), the National Basic Research Program of China (No. 2014CB931800), and the Users with Excellence and Scientific Research Grant of Hefei Science Center of CAS (No. 2015HSC-UE007).
文摘Stretchable electronics are in high demand for next-generation wearable devices, but their fabrication is still challenging. Stretchable conductors, flexible pressure sensors, and foldable light-emitting diodes (LEDs) have been reported; however, the fabrication of stable stretchable batteries, as power suppliers for wearable devices, is significantly behind the development of other stretchable electronics. Several stretchable lithium-ion batteries and primary batteries have been fabricated, but their low capacities and complicated manufacturing processes are obstacles for practical applications. Herein, we report a stretchable zinc/manganese-oxide (Zn-MnO2) full battery based on a silver-nanowire- coated sponge prepared via a facile dip-coating process. The spongy electrode, with a three-dimensional (3D) binary network structure, provided not only high conductivity and stretchability, but also enabled a high mass loading of electrochemically active materials (Zn and MnO2 particles). The fabricated Zn-MnO2 battery exhibited an areal capacity as high as 3.6 mAh·cm^-2 and could accommodate tensile strains of up to 100% while retaining 89% of its original capacity. The facile solution-based strategy of dip-coating active materials onto a cheap sponge-based stretchable current collector opens up a new avenue for fabricating stretchable batteries.
基金supported by the National Key Research and Development Program of China(2017YFB0307000)the National Natural Science Foundation of China(51973093,U1533122 and 51773094)+5 种基金the Natural Science Foundation of Tianjin(18JCZDJC36800)the Science Foundation for Distinguished Young Scholars of Tianjin(18JCJQJC46600)the Fundamental Research Funds for the Central Universities(63171219)the State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,Donghua University(LK1704)the National Special Support Plan for High-level Talents people(C041800902)the Eugene McDermott Graduate Fellows Program。
文摘The elastic conductor is crucial in wearable electronics and soft robotics.The ideal intrinsic elastic bulk conductors show uniform three-dimensional conductive networks and stable resistance during large stretch.A challenge is that the variation of resistance is high under deformation due to disconnection of conductive pathway for bulk elastic conductors.Our strategy is to introduce buckled structure into the conductive network,by self-assembly of a carbon nanotube layer on the interconnecting micropore surface of a prestrained foam,followed by strain relaxation.Both unfolding of buckles and flattening of micropores contributed to the stability of the resistance under deformation(2.0%resistance variation under 70%strain).Microstructural analysis and finite element analysis illustrated different patterns of two-dimensional buckling structures could be obtained due to the imperfections in the conductive layer.Applications as all-directional interconnects,stretchable electromagnetic interference shielding and electrothermal tumor ablation were demonstrated.
文摘锂硫电池因其能量密度高、成本低等优势被认为是最具希望的下一代储能器件之一,然而其正极材料的发展和应用仍面临诸多挑战.本文通过将剥离的Ti_(3)C_(2)纳米片在NaOH溶液中刻蚀得到具有交联结构的Ti_(3)C_(2)纳米线,并利用熔融浸渍法负载硫颗粒,用作锂硫电池的正极材料.具有极性表面的Ti_(3)C_(2)可有效捕获多硫化锂中间体,从而抑制多硫化锂的穿梭效应.与Ti_(3)C_(2)纳米片相比,具有交联网络状结构的Ti_(3)C_(2)纳米线具有更大的比表面积和多孔结构,可以有效提供固硫所需的空间,并容纳硫在锂化过程中的体积膨胀.其较大的比表面积有利于Ti_(3)C_(2)纳米线对多硫化锂的捕获,其多孔结构有利于锂离子的扩散.Ti_(3)C_(2)纳米线/硫复合物展现出优异的电化学性能,在0.2 C的倍率下,100次循环后,其可逆容量为658 mAh g^(−1);在1 C倍率下,300次循环后,Ti_(3)C_(2)纳米线/硫复合物仍能保持436 mAh g^(−1)的可逆容量.
基金This research was funded by the South Dakota Board of Regent(Proof of Concept).
文摘High-performance nanogrease manufactured from carbon nanomaterials is observed to be stable and homogeneous and have superb physical properties,such as thermal and electrical conductivities,compared with current commercial greases made of lithium,calcium,and aluminum.For the first time,carbon nanomaterials have been observed to disperse well as the sole thickeners in oil systems,e.g.,polyalphaolefin and polyester(ROYCO),without the aid of any chemical surfactants.Three-dimensional percolation network structures that exist among carbon nanomaterials are easily scalable,which can be attributed to the intermolecular van der Waals forces.Moreover,the introduction of hydrogen bonding in any form to grease significantly increases its thermal and electrical conductivities and substantially reduces the weight percentage of carbon nanomaterials needed to fabricate stable grease.For example,loading of only 1.4 wt%hydroxyl-functionalized multiwalled carbon nanotube(MWNT-OH)with Krytox XHT750 oil leads to a 37.8%increase in thermal conductivity.Moreover,75%glycerol,25% water,and 4.5 wt% MWNT-OH yielded the lowest electrical resistivity of 10.0 Ω cm.This finding can be extended to hydrogen bonding materials with functional groups,such as OH,COOH,F,and NH.The nanogrease reported in this study has been manufactured using the three-roll mill method,which is an easy and cost-effective method,as the loading weight percentage of carbon nanomaterials to fabricate stable grease decreases from 12 wt% to 3-4 wt%.Furthermore,the process is easily scalable,reproduced,and optimized.This novel high-performance nanogrease has a high commercial value and numerous applications and could replace current commercial greases.