分类: 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间: 2017-05-08
摘要: MoS2 nanoflowers consisting of nanosheets are synthesized by a one-step hydrothermal method. The interlayer distances of the MoS2 nanosheets, accompanied with the changes of crystallinity, defects, specific surface areas as well as the thickness of the MoS2 nanosheets, can be well controlled via simply altering hydrothermal reaction temperatures. The effect of interlayer distances on the lithium storage capability for lithium ion batteries is investigated. The results show that MoS2 synthesized under 200 C with an interlayer distance of 0.65 nm exhibit the highest lithium storage capacity and the best rate capability, showing a high discharge capacity of 814.2 mA h g 1 at 100 mA g 1 after 50 cycles and as highas652.2mAhg 1 and547.3mAhg 1 atcurrentdensitiesof1Ag 1 and2Ag 1 at25 C, respectively. The excellent lithium storage properties of the resultant MoS2 nanoflowers are attributed to its controllable optimized interplanar distance with good crystallinity, appropriate surface area and defects as well as thickness of the nanosheets.
分类: 化学 >> 物理化学 提交时间: 2017-11-05 合作期刊: 《结构化学》
摘要: A new complex [Cd2(L)2(Cl)2(H2O)]n (1) was synthesized by reacting CdCl2·2.5H2O with 4-(1,2,4-triazol-4-yl)phenylacetic acid (HL) ligand. The structure of the complex was characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental analysis and PXRD. Complex 1 crystallizes in triclinic, space group P21/c with a = 11.4303(8), b = 14.1792(10), c = 14.6857(10) Å, β = 96.3780(10)º, V = 2365.4(3) Å3, Z = 4, C20H16Cl2N6O5Cd2, Mr = 716.09, Dc = 2.011 g/cm3, μ = 2.069-1, S = 1.051, F(000) = 1392, the final R = 0.0458 and wR = 0.0949 for 5402 observed reflections (I > 2σ(I)). Complex 1 is a two-dimensional (2D) layer structure and non-covalent bonding interactions such as C–H···π and π···π extend the 2D to form a three-dimensional supramolecular polymer.
分类: 化学 >> 物理化学 提交时间: 2017-11-05 合作期刊: 《结构化学》
摘要: The title compound, ethyl (R)-2-(biphenyl-4-carbonyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4- b]indole-1-carboxylate (C27H24N2O3) has been synthesized, and its structure was characterized by 1H-NMR, 13C-NMR, ESI-MS and single-crystal X-ray diffraction. It crystallizes in the orthorhombic system, space group Pbca with a = 16.9950(8), b = 9.5445(4), c = 28.3188(3) Å, V = 4593.6(3) Å3, Z = 8, T = 294.64(10) K, μ(MoKα) = 0.08 mm-1, Dc = 1.228 g/cm3, F(000) = 1792.0 and GOOF = 1.036. 11836 reflections were measured (7.04≤2θ≤52.04°), and 4506 were unique (Rint = 0.0393, Rsigma = 0.0546) and used in all calculations. The final R = 0.0576 (I > 2σ(I)) and wR = 0.1563 (all data). The preliminary biological tests show that the title compound has a good antitumor activity against Hela in vitro with the IC50 value of 4.71 μmol/L.
分类: 核科学技术 >> 核材料与工艺技术 提交时间: 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要: Magnetically assisted chemical separation process is an efficient method used widely in separating radionuclides and heavy metals in environmental samples. It is simple, compact and cost-effective, with less secondary waste streams. Tributyl phosphate (TBP)-coated magnetic poly (styrene-divinylbenzene) (Pst-DVB) nano-particles were synthesized and characterized by transmission electron microscopy, scanning electron microscopy, vibrating sample magnetometer, thermogravimetry and Fourier transform infrared spectrometry. The application of TBP-coated magnetic Pst-DVB particles in separating low concentration of uranium from aqueous media was evaluated, and the equilibrium adsorption isotherm was investigated. Our results indicate that the TBP-coated magnetic Pst-DVB particles may be of potential application for uranium separation.
分类: 化学 >> 物理化学 提交时间: 2017-11-05 合作期刊: 《结构化学》
摘要: Two coordination polymers (CPs), {[Ag(ADA)0.5(DPE)]·H2O}n (1) and {[Ag(ADA)0.5(Bipy)0.5]·H2O}n (2), (H2ADA = 3,3-azodibenzoic acid, DPE = 1,2-di(4-pyridyl)- ethylene, Bipy = 4,4΄-bipyridine), have been synthesized via solvothermal reactions of Ag+ with ADA2- and/or DPE, Bipy. CPs 1 and 2 were characterized by elemental analyses, IR spectra, thermal behaviors, and X-ray single-crystal diffraction. CPs 1 and 2 feature “Ag···Ag” subunits. CP 1 shows a 3D construction, in which the “Ag···Ag” subunits extend through ADA2- and DPE ligands using μ6-kO,O;kO;kO;kO,O;kO;kO and μ2-kO;kO coordination modes, respectively. It crystallizes in triclinic system, space group P, with a = 0.3808(18), b = 1.2476(6), c = 1.309(6) nm, α = 76.757(5), β = 84.649(5), γ = 86.809(5)º, V = 0.6024(5) nm3, Z = 2, Mr = 351.11, C13H11AgN2O3, Dc = 1.936 g/cm3, F(000) = 348, S = 1.064, R = 0.0323 and wR = 0.0689. CP 2 exhibits a 3D supramolecular structure, in which the “Ag···Ag” subunits are connected by ADA2- and DPE ligands with μ6-kO;kO;kO,O;kO;kO and μ2-kO;kO coordination modes, respectively. Ultimately, through hydrogen bond and π···π interaction, the “Ag···Ag” subunits stabilize the 3D supramolecular structure of 2. It crystallizes in monoclinic, space group C2/c, with a = 25.301(15), b = 13.197(8), c = 6.970(4) nm, β = 102.597(7)º, V = 2.271(2) nm3, Z = 8, C12H10AgN2O2.50, Mr = 330.09, Dc = 1.931 g/cm3, F(000) = 1304, S = 1.082, R = 0.1107 and wR = 0.2984. The fluorescence properties of CPs 1 and 2 have been also investigated.
分类: 化学 >> 物理化学 提交时间: 2017-11-05 合作期刊: 《结构化学》
摘要: Two new inorganic-organic hybrid vanadogermanates H[Cd(en)(phen)(H2O)][Cd(en)(phen)]{[Cd(phen)]2[Ge8V12O41(OH)7]}�H2O (1) and [Cd(dien)2][Cd(dien)]2{[Cd(phen)]2Ge8V12O42(H2O)(OH)6}�.5H2O (2) (en = ethylenediamine, dien = diethylenetriamine, phen = 1,10-phenanthroline) have been synthesized by hydrothermal method. Their structures were measured by single-crystal X-ray diffractions, thermogravimetric analysis, powder X-ray diffractions and infrared spectra. Structural analysis reveals that compound 1 is an infrequent dimeric structure based on di-Cd-substituted Ge-V-O cluster and transition-metal complex bridges, while compound 2 is an infinite 1-D chain constructed from di-Cd-substituted Ge-V-O clusters and dinuclear bridging complexes. Magnetic measurement indicated that both 1 and 2 exhibit antiferromagnetic behaviors.
分类: 化学 >> 物理化学 提交时间: 2017-11-05 合作期刊: 《结构化学》
摘要: Four new coordination compounds, [Zn(bppc)2(H2O)2]·3H2O (1), [Zn2(bppc)2(m-bdc)(H2O)4]·7H2O (2), [Zn(bppc)2(H2O)2]n·n(m-Hbdc)·n(H2O) (3), [Zn2(bppc)(btc)(H2O)3]n·5nH2O (4) (Hbppc = 2,6-bis(pyrazin-2-yl)pyridine-4-carboxylate, H2(m-bdc) = 1,3-benzenedicarboxylic acid, H3btc = 1,3,5-benzene-tricarboxylic acid), have been hydrothermally synthesized and structurally characterized. Compound 1 shows a mononuclear structure and 2 shows a dinuclear structure. Compound 3 is a one-dimensional chain structure, which is extended into a 3D supramolecular network by intermolecular hydrogen interactions. In 4, a 1D loop-like chain is connected by (btc)3- anions to generate a 2D layer structure. The structure differences of 1~4 show that the pH and aromatic acid as auxiliary ligand have important influence on the final structures.[1]Additionally, the luminescent properties of 1~4 have been investigated with fluorescent spectra in the solid state, and 1~4 display a strong fluorescent emission at room temperature and have potential applications as fluorescent-emitting materials.
分类: 化学 >> 物理化学 提交时间: 2017-11-05 合作期刊: 《结构化学》
摘要: One novel phenoxyacetamide derivative (C22H28N2O3, Mr = 368.47) has been synthesized and determined by means of NMR spectroscopy, high resolution mass spectra and single-crystal X-ray diffraction. The single crystal belongs to the monoclinic system, space group Cc with a = 14.910(3), b = 14.592(3), c = 38.683(8) Å, β = 100.37(3)°, V = 8279(3) Å3, Z = 16, Dc = 1.183 g/cm3, F(000) = 3168, μ = 0.079 mm-1, MoKα radiation (λ = 0.71073 Å), the final R = 0.0508 and wR = 0.0666 for 4120 observed reflections with I > 2σ(I). There are four independent molecules in an asymmetric unit cell. The four symmetry-independent molecules have a variety of different conformations indicating considerable conformational freedom. The bioassay results indicated that the title compound displayed effective activities against glutamine-induced neurotoxicity in PC12 cells and significantly prolonged the survival time of mice subjected to acute cerebral ischemia.
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间: 2017-05-02
摘要: This paper reported the synthesis of bio-based unsaturated poly(ester- urethane)s via a nonisocyanate route, by metal-catalyzed melt poly- condensation of itaconic acid with urethanediols. Three novel types of bio-based unsaturated poly(ester-urethane)s, namely, poly- (urethanediol 2-itaconic acid), poly(urethanediol 4-itaconic acid) and poly(urethanediol 6-itaconic acid) (poly(U2-IA), poly(U4-IA) and poly (U6-IA) for short code, respectively), were prepared by a green synthetic route. The urethane linkage was formed by the reaction of two equivalent of ethylene carbonate with 1,6-hexanediamine, 1,4- butanediamine and 1,2-ethanediamine to form urethanediols. The urethanediols underwent polymerization with itaconic acid (IA) in the presence of metal catalyst dibutyltin dilaurate (DBTL) to produce low- molecular-weight bio-based unsaturated polyurethanes. Then, these bio-based unsaturated poly(ester-urethane)s were formulated with free radical photoinitiator and curing promoter to prepare UV curable polyurethane systems. After UV curing, the tensile properties, thermal properties and general coating properties of the three UV-cured polyurethane films were similar to that of UV cured polyurethane films prepared by polyurethane-acrylate (PUA). The results suggested that the obtained bio-based unsaturated polyurethanes could serve as coating materials.
分类: 材料科学 >> 纳米科学和纳米技术 提交时间: 2017-05-07
摘要: In this paper a kind of copper oxide material of copper–polyphenols complex nanoparticles (Cu–P NPs) were synthesized by Cinnamomum pedunculatum leaves extract, which have different morphology and appearance compared with usual copper oxides Cu2O and CuO. For better understanding about this material, the Cu–P NPs were characterized using scanning electron microscopy (SEM), X-ray absorption spectroscopy (XAS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). It was found that synthesized Cu–P NPs were amorphous with spherical particles ranged from 80 to 500 nm. XAS data analysis indicated that the synthesized Cu–P NPs has different molecular structure with Cu2O and CuO. It is assumed that the copper ions chelated with polyphenol molecule. The nanoparticles showed a clear anti Escherichia coli activity in this study, and may also be used in fields of semiconductor, ceramic, catalyst, and sensor. This synthesis approach provided a novel route to manufacture copper oxide nanomaterial.
提交时间: 2017-05-02
摘要: Intermediate tin oxide [Sn3O4] crystals have been successfully synthesized through a simple one-pot hydrothermal route by employing SnCl2 center dot 2H[2]O and NaOH as raw materials. The crystmlline structure, morphology and optical properties of Sn3O4 ma
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间: 2017-05-02
摘要: Titania-hydroxyapatite (HA) nanocomposites were fabricated by wet chemical synthesis approach. HA exhibited crystallographic orientation of nucleation on nano titania particle, forming the composite particles with titania being partially enwrapped with HA. Microstructural characterization by high res- olution transmission electron microscopy revealed coherent interfacial bond of (110) and (222) planes of HA crystal with (101) plane of anatase. The HA layer promoted significantly recruitment of Escherichia coli bacteria onto the titania-based particles for subsequent photocatalytic killing. Less extent of enwrapping of HA on titania particle, as accomplished by increasing the aging time of HA suspension, gave rise to better capability of photocatalytic degradation of methylene blue and sterilization of the bacteria. The novel HA-enwrapped titania powder shows great potential for environmental applications.
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间: 2017-05-02
摘要: Porous silicon/carbon (Si/C) structure has been proved of great help to enhance the electrochemical cycling performance of Si-based anode materials. Current fabrication of porous Si based anodes usually relies on the complicated chemical etching process with unavoidable pollution problem. Herein, a na- noporous Si/C composite was successfully fabricated by a facile spray drying and carbonization process. The environmentally benign NaCl is used as the sacrificing template for the generation of embedded nanopores, which can be easily removed by routine washing process. The as-prepared nanoporous Si/C anode exhibits a high reversible specific capacity of around 900 mAh g 1 with 78.2% capacity retention after 100 cycles. This synthetic method paves a simple and environment-friendly way to build porous Si based anode with improved electrochemical performance which is significantly important for the in- dustrial production.
分类: 计算机科学 >> 自然语言理解与机器翻译 提交时间: 2016-06-18
摘要: This letter presents a perceptually weighted analysis -by-synthesis vector quantization (VQ) algorithm for low bit rate MFCC codec. Different from conventional VQ of MFCCs vector, this algorithm uses an analysis-by-synthesis technique and aims to minimize the perceptually weighted spectral reconstruction distortion rather than the distortion of MFCCs vector itself. Also, to reduce the computational complexity, we propose a practical suboptimal codebook searching technique and embed it into the split and multistage vector quantization framework. Objective and subjective experimental results for Mandarin speech show that the proposed algorithm yields intelligible and natural sounding speech for speech coding at 600--2400 bit/s. Compared to current VQ in MFCC codec, the output speech quality is substantially improved in terms of frequency-weighted segmental SNR, STOI, PESQ and MOS score.
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间: 2017-05-02
摘要: An intrinsically flame retardant bio-based benzoxazine (diphenolic acid pentaerythritol caged phosphate benzoxazine, DPA-PEPA-Boz) monomer was synthesized from bio-based diphenolic acid (DPA) using a four-step process. The monomer of DPA-PEPA-Boz was characterized by FT-IR, 1H NMR and 13C NMR. The curing behavior of DPA-PEPA-boz was studied and compared with those of DPA based benzoxazine (DPA- Boz) and DPA ester derivative (MDP) based benzoxazine (MDP-Boz) without PEPA by means of non- isothermal differential scanning calorimetry. The results indicated that DPA-PEPA-Boz system showed a two-stage curing, assigned to the exothermic opening reactions of oxazine rings and PeOeC ring in PEPA respectively, while the DPA-Boz and MDP-Boz showed a one-stage curing. In addition, the effect of the introduction of PEPA on thermal and inflammable properties of the resin was evaluated. The residual char of the cured DPA-PEPA-Boz (P-DPA-PEPA-Boz) after 400 C was much higher than those of cured DPA-Boz (P-DPA-Boz) and cured MDP-Boz (P-MDP-Boz) under nitrogen and air atmospheres. Meanwhile, total heat release (THR), peak heat release rate (PHRR) and heat release capacity (HRC) of P-DPA-PEPA- Boz were about half of those of P-DPA-Boz and P-MDP-Boz. P-DPA-PEPA-Boz had a limiting oxygen index (LOI) of 33.5% and achieved V0 rating in UL94 test. P-DPA-PEPA-Boz behaved as a very good intrinsic thermal and flame retardant bio-based benoxazine resin.
分类: 材料科学 >> 材料科学(综合) 提交时间: 2023-12-05
摘要: This study synthesized copper-substituted lead apatite using the hydrothermal method, starting from hydroxyapatite precursors. For stability, it is recommended to maintain copper substitution below x=2 in the Pb10-xCux(PO4)O apatite. The introduction of copper appropriately reduces the lattice constant, in line with DFT theoretical calculations. Non-equilibrium heat treatment introduces additional charge carriers; oxygen-rich tempering shifts the sample to paramagnetism, while anaerobic tempering leads to complex and unique hysteresis loops. Non-equilibrium annealing can increase carrier concentration, but its efficacy is limited. Although some improvements have been observed, further exploration involving additional element doping or seeking interfaces with suitable conductive phases is needed to achieve superconductivity.
分类: 化学 >> 物理化学 提交时间: 2017-11-05 合作期刊: 《结构化学》
摘要: A new metal-organic cadmium coordination polymer [Cd(pzdc)0.5(L)]n·nH2O (1, H2pzdc = pyrazine-2,3-dicarboxylic acid, HL = 3-(2-pyridyl)pyrazole) has been successfully synthesized under hydrothermal conditions. The structure has been determined by single-crystal X-ray diffraction analysis, elemental analyses, IR and fluorescence spectrum. Brown crystals crystallize in the orthorhombic system, space group Fdd2 with a = 11.2636(9), b = 38.296(3), c = 10.5795(8) Å, V = 4563.5(6) Å3, C11H9CdN4O3, Mr = 357.62, Dc = 2.082 g/cm3, μ(MoKα) = 1.924 mm-1, F(000) = 2800, Z = 16, the final R = 0.0169 and wR = 0.0443 for 2106 observed reflections (I > 2s(I)). It shows a two-dimensional network structure and extends into a three-dimensional supramolecular framework through π-π stacking interactions. Moreover, we analyzed Natural Bond Orbital (NBO) by using the PBE0/LANL2DZ method built in Gaussian 03 Program. The calculation results showed obvious covalent interaction between the coordinated atoms and Cd(II) ion.
分类: 化学 >> 物理化学 提交时间: 2017-11-05 合作期刊: 《结构化学》
摘要: A new Mn(II) complex, [Mn0.5(tdc)0.5(L)]2n (1, H2tdc = 2,5-thiophenedicarboxylic acid, L = 3-(2-pyridyl)pyrazole), has been successfully synthesized under hydrothermal conditions. Its structure has been determined by single-crystal X-ray diffraction analysis, elemental analyses, IR, TG and UV spectrum. Single-crystal X-ray diffraction analysis reveals that complex 1 belongs to the orthorhombic system, space group Pnna with a = 11.5184(6), b = 16.8399(8), c = 11.7249(5) Å, V = 2274.26(19) Å3, Z = 4, Dc = 1.505 g/cm3, μ = 0.715 mm-1, Mr = 515.41, F(000) = 1052, the final R = 0.0336 and wR = 0.0802 with I > 2σ(I). It exhibits a one-dimensional zigzag-chain structure, which was stabilized through intermolecular C–H···O and intramolecular N–H···O hydrogen bonding interactions. Moreover, we analyzed Natural Bond Orbital (NBO) by using the PBE0/LANL2DZ method built in Gaussian 09 Program. The calculation results showed obvious covalent interaction between the coordinated atoms and Mn(II) ion.
分类: 化学 >> 物理化学 提交时间: 2017-11-05 合作期刊: 《结构化学》
摘要: Two new complexes [Ag(bix)]n·nNAA·nH2O (1) and [Cd(NAA)(phen)2(H2O)]2·2CH3COO-·H2O (2) (bix = 1,4-bis(imidazol-1-ylmethyl)benzene, HNAA = α-naphthylacetic acid, phen = 1,10-phenanthroline) have been successfully synthesized under hydrothermal conditions. Their structures have been determined by elemental analyses, IR spectroscopy, TG and single-crystal X-ray diffraction analysis. The intermolecular hydrogen bonding or π-π stacking interactions extend the complexes into a 3D supramolecular structure. Moreover, the luminescent properties of complex 2 have been investigated in the solid state.
分类: 化学 >> 物理化学 提交时间: 2017-11-05 合作期刊: 《结构化学》
摘要: A new complex [Zn(4-nph)(bib)]2n·nH2O (1) has been obtained by the reaction of metal (Zn(II)), 1,4-bis(imidazol-1-yl)-butane (bib) with 4-nitrophthalic acid (4-H2nph). The crystal structure of 1 has been determined by single-crystal X-ray diffraction analysis. Compound 1 is of triclinic system, space group P with a = 10.3251, b = 12.4503, c = 16.6497 Å, α = 88.487(3), β = 72.529(3), γ = 79.991(3)°, V = 2009.8(5) Å3 and Mr = 945.47. Complex 1 shows a three-dimensional (3D) framework. Moreover, through intermolecular hydrogen bonds, compound 1 is assembled into a supramolecular structure. The thermal stability and luminescent properties of 1 are also investigated.