混凝土薄壳球形水窖结构的优化设计

分析球形水窖空间结构的应力分布情况并进行几何尺寸优化,避免建设者根据经验来确定球形水窖的厚度、构造及混凝土标号,以节省建窖材料,同时防止应力不足而发生破坏。【方法】利用基于ANSYS平台新开发的窖体有限元分析软件,对实际中窖壁厚度为4和11 cm的混凝土薄壳球形水窖进行空间结构应力分析,同时以水窖耗材量最小为目标函数,以许用应力和变形量为约束条件,对其进行几何尺寸优化。【结果】计算得出窖壁厚度为4和11 cm的水窖最大拉应力分别为1 380.00和447.31 kPa,最大压应力分别为5 153.20和1 896.70 kPa;优化出空窖不利工况下容积为20,30和40 m3的球形水窖窖壁最佳厚度,即栗钙土地区分别为0.051,0.061和0.065m,黄土地区分别为0.050,0.059和0.062 m。【结论】经软件优化计算后的球形水窖结构,既能满足强度和刚度的要求,同时也最大限度地节约了材料用量;利用新开发的窖体结构优化分析软件,能够对球形水窖进行空间应力分析与结构优化,可以作为球形水窖设计软件。

Finite element simulation of the physical gelation of rennet casein(酶凝干酪素物理凝胶化过程的有限元模拟)

以酶凝干酪素的凝胶化过程为对象,利用有限元方法数值分析了在凝胶化过程中温度场的空间分布和时间演变规律.在此基础上,基于一阶的凝胶化动力学方程,数值模拟了凝胶体系的复剪切模量场,进而分析了材料配方、体系尺寸与冷却方案对复剪切模量场的影响规律.模拟结果表明,由于热阻的差异,体系表面的冷却速率大于内部,表面首先发生凝胶化;而由于预凝胶化阶段的平均冷却速率决定了无穷复剪切模量的值,最终体系内部的复剪切模量超过表面的.

A multifunctional iridium carbazolyl orange phosphor for high performance two-element WOLED exploiting exciton-managed fluorescence/phosphorescence

By attaching a bulky, inductively electron-with drawing trifluoromethyl (CF3) group on the pyridyl ring of the rigid 2-[3(N-phenylcarbazolyl)]pyridine cyclometalated ligand, we successfully synthesized a new heteroleptic orange-emitting phosphorescent iridium(III) complex [Ir(L-1)(2)(acac)] 1 (HL1=5-trifluoromethyl-2-[3-(N-phenylcarbazolyl)]pyridine, Hacac = acetylacetone) in good yield.

Synthesis of novel star-like hyperbranched polymers with poly(amido amine) core and poly(L-lysine) shell

Hyperbranched poly(amido amine)s containing vinyl and hydroxyl groups were successfully synthesized via Michael addition polymerization of triacrylamide (TT) and 3-amino-1,2-propanediol (APD) with equal molar ratio in feed. H-1, C-13 and HSQC NMR techniques were used to clarify the structure of hyperbranched polymers and polymerization mechanism.

Fabrication and luminescent properties of the core-shell structured YNbO4 : Eu3+/Tb3+@SiO2 spherical particles

The core-shell structured YNbO4:Eu3+/Tb3+@SiO2 particles were realized by coating the YNbO4:Etr(3+)/Tb3+ phosphors onto the surface of spherical silica via a sol-gel process. The obtained materials were characterized by means of X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transform IR spectroscopy (FT-IR), photoluminescence (PL) spectra, and cathodoluminescence (CL) spectra.

Formation of reversible shell cross-linked micelles from the biodegradable amphiphilic diblock copolymer poly(L-cysteine)-block-poly(L-lactide)

A novel biodegradable diblock copolymer, poly(L-cysteine)-b-Poly(L-lactide) (PLC-b-PLLA), was synthesized by ring-opening polymerization (ROP) of N-carboxyanhydride of beta-benzyloxycarbonyl-L-Cysteine (ZLC-NCA) with amino-terminated Poly(L-lactide) (NH2-PLLA) as a macroinitiator in a convenient way. The diblock copolymer and its precursor were characterized by H-1 NMR, Fourier transform infrared (FT-IR), gel permeation chromatography (GPC), and X-ray photoelectron spectroscopy (XPS) measurements. The length of each block polymer could be tailored by molecular design and the ratios of feeding monomers.

Amphiphilic Core-Shell Nanocarriers Based On Hyperbranched Poly(ester amide)-star-PCL: Synthesis, Characterization, and Potential as Efficient Phase Transfer Agent

Amphiphilic biodegradable star-shaped polymer was conveniently prepared by the Sn(Oct)(2)-catalyzed ring opening polymerization of c-caprolactone (CL) with hyperbranched poly(ester amide) (PEA) as a macroinitiator. Various monomer/initiator ratios were employed to vary the length of the PCL arms. H-1 NMR and FTIR characterizations showed the successful synthesis of star polymer with high initiation efficiency. SEC analysis using triple detectors, RI, light scattering, and viscosity confirmed the controlled manner of polymerization and the star architecture.

Synthesis of magnetite core-shell nanoparticles by surface-initiated ring-opening polymerization of L-lactide

Fe3O4-polylactide (PLA) core-shell nanoparticles were perpared by surface functionalization of Fe3O4 nanoparticles and subsequent surface-initiated ring-opening polymerization of L-lactide. PLA was directly connected onto the magnetic nanoparticles surface through a chemical linkage. Fourier transform infrared (FT-IR) spectra directly provided evidence of the PLA on the surface of the magnetic nanoparticles. Transmission electron microscopy images (TEM) showed that the magnetic nanoparticles were coated by PLA with a 3-nm-thick shell.

Multilayered core-shell structure of the dispersed phase in high-impact polypropylene

The multiphase morphology of high impact polypropylene (hiPP), which is a reactor blend of polypropylene (PP) with ethylene-propylene copolymer, was investigated by transmission electron microscopy, selected area electron diffraction, atomic force microscopy, and field-emission scanning electron microscopy techniques in conjunction with an analysis of the hiPP composition and chain structure based on solvent fractionation, C-13-NMR, and differential scanning calorimetry measurements.

A facile pathway to prepare enzymatically degradable microcapsules with tunable capsule shell properties

Dextran sulfate (DS)/poly-L-lysine (PLL) microcapsules are fabricated by an in situ coacervation method using DS-doped CaCO3 microparticles as templates. Twinned superstructures or spherical CaCO3 microparticles are produced depending on DS concentration in the starting Solution. DS/PLL microcapsules with ellipsoidal or spherical outline are obtained after removal of templates in disodium ethylene diamine tetraacetate dehydrate (EDTA) without PLL. Their shell thickness and negative surface charges increase with the DS weight percentage in the templates. The surface potential of DS/PLL microcapsules.

Novel Hybrid Electrocatalyst with Enhanced Performance in Alkaline Media: Hollow Au/Pd Core/Shell Nanostructures with a Raspberry Surface

In this paper, a hollow Au/Pd core/shell nanostructure with a raspberry surface was developed for methanol, ethanol, and formic acid oxidation in alkaline media. The results showed that it possessed better electrocatalyst performance than hollow Au nanospheres or Pd nanoparticles. The nanostructure was fabricated via a two-step method. Hollow Au nanospheres were first synthesized by a galvanic replacement reaction, and then they were coated with a layer of Pd grains. Several characterizations such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS) were used to investigate the prepared nanostructures.

Fabrication of Iron Oxide Core/Gold Shell Submicrometer Spheres with Nanoscale Surface Roughness for Efficient Surface-Enhanced Raman Scattering

A method to synthesize Fe3O4 core/Au shell submicrometer structures with very rough surfaces on the nanoscale is reported. The Fe3O4 particles were first modified with uniform polymers through the layer-by-layer technique and then adsorbed a lot of gold nanoseeds for further Au shell formation. The shell was composed of a large number of irregular nanoscale An particles arranged randomly, and there were well-defined boundaries between these Au nanoparticles. The Fe3O4 core/Au shell particles showed strong plasmon resonance absorption in the near-infrared range, and can be separated quickly from solution by an external magnet.

A magnetic, luminescent and mesoporous core-shell structured composite material as drug carrier

In this paper, hydrothermal synthesized Fe3O4 microspheres have been encapsulated with nonporous silica and a further layer of ordered mesoporous silica through a simple sol-gel process. The surface of the outer silica shell was further functionalized by the deposition of YVO4:Eu3+ phosphors, realizing a sandwich structured material with mesoporous, magnetic and luminescent properties. The multifunctional system was used as drug carrier to investigate the storage and release properties using ibuprofen (IBU) as model drug by the surface modification. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS), Fourier transform infrared spectroscopy (FT-IR), N-2 adsorption/desorption, photoluminescence (PL) spectra, and superconducting quantum interference device (SQUID) were used to characterized the samples.

Preparation and characterization of poly (N-isopropylacrylamide)/polyvinylamine core-shell microgels

In this paper, well-defined temperature- and pH-sensitive core-shell microgels were synthesized by graft copolymerization in the absence of surfactant and stabilizer. The microgel particles consisted of poly (N-isopropylacrylamide (NIPAm)) core crosslinked with N, N'-methylene-bisacrylamide (MBA) and polyvinylamine (PVAm) shell. The effect of MBA content and NIPAm/PVAm ratio on microgel size was investigated. SEM showed that the microgels were spherical and had narrow particle-size distribution. TEM images of the microgels clearly displayed well-defined core-shell morphologies. Zeta-potential measurement further elucidated that the microgels possessed positively charged PVAm molecules on the microgel surface. Turbidity measurement and H-1-nuclear magnetic resonance (NMR) experiments indicated that the VPTT of microgels was the same as the LCST of PNIPAm.

Synthesis and characterization of monodisperse spherical SiO2@RE2O3 (RE = rare earth elements) and SiO2@Gd2O3:Ln(3+) (Ln = Eu, Tb, Dy, Sm, Er, Ho) particles with core-shell structure

Spherical SiO2 particles have been coated with rare earth oxide layers by a Pechini sol-gel process, leading to the formation of core-shell structured SiO2@RE2O3 (RE = rare earth elements) and SiO2@Gd2O3:Ln(3+) (Ln = Eu, Tb, Dy, Sm, Er, Ho) particles. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), photoluminescence (PL), and cathodoluminescence spectra as well as lifetimes were used to characterize the resulting SiO2@RE2O3 (RE = rare earth elements) and SiO2@Gd2O3:Ln(3+) (Eu3+, Tb3+, Dy3+, Sm3+, Er3+, Ho3+) samples. The obtained core-shell phosphors have perfect spherical shape with narrow size distribution (average size ca. 380 nm), smooth surface and non-agglomeration. The thickness of shells could be easily controlled by changing the number of deposition cycles (40 nm for two deposition cycles).