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1.
高层间距的羟基硅铝交联蒙托土的合成与表征 总被引:2,自引:0,他引:2
采用溶胶分散法合成了一系列高层间距(2.6nm)的羟基硅铝交联蒙托土(SiAl-CLM),并用~(27)Al NMR、XRD、DTA、XPS、吡啶吸附-IR、正丁胺吸附-TPD等技术进行了表征,用脉冲反应技术考察了其催化活性。结果表明:SiAl-CLM层间存在氧化硅胶团与羟基铝聚体形成的复合Si-Al柱.SiAl-CLM的热稳定性较好,对异丙苯的裂解活性(76.8%)较高。Si的引入增加了交联蒙托土的表面酸性,尤其增加了Bronsted酸性。 相似文献
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以低硅铝比焙烧后的硅铝胶固体为初始原料,在含F-近中性与低含水量体系下晶化合成出相对高结晶度的纳米富铝β沸石。实验考察了合成条件、硅铝胶焙烧对晶化产物的影响和晶化过程中Al配位状况变化,并采用XRD、XRF、SEM/TEM2、7AlMAS NMR物化方法对晶化产物进行表征。结果表明,含F-离子、H2O/SiO2摩尔比为2.4~6.0以及高温焙烧硅铝胶有利于合成高结晶度的纳米富铝β沸石;硅铝胶固体焙烧后能产生易于转化为β沸石晶核的Al四配位结构,而部分六配位Al在晶化过程中缓慢溶入β沸石晶核中而最终生成纳米富铝β沸石。 相似文献
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以自制不对称双子季铵盐表面活性剂为模板, 在水热合成体系中控制合成系列硅铝比纳米薄层ZSM-5分子筛.采用X射线衍射(XRD)、N2吸附-脱附、X射线荧光光谱(XRF)、扫描电镜(SEM)和27Al魔角旋转核磁共振(27Al MAS-NMR)对合成的样品进行了表征. 详细研究了晶化温度、晶化时间、结构导向剂(SDA)用量、碱度等对合成的影响和纳米薄层ZSM-5分子筛的形成过程. 结果表明: 分子筛硅铝比越高, 结构导向剂用量越大, 所需的晶化时间越短; 晶化温度越高, 晶化时间越短; 且不同硅铝比纳米薄层ZSM-5分子筛的形貌规整度、比表面积和介孔/微孔孔容比例随着硅铝比而变化. 相似文献
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Pt/Au双金属纳米粒子的制备及表征 总被引:6,自引:1,他引:6
Poly (N-vinyl-2-pyrrolidone)-protected Pt/Au bimetallic nanoparticles were obtained by reducing the mixture of HAuCl4 and H2PtCl6 with sodium borohydride. UV-vis spectra, transmission electronic microscopy and X-my diffraction reveal that the prepared bimetallic nanoparticles are of alloy structure. 相似文献
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新型催化剂载体材料—镁铝复合氧化物的制备及其物理化学性质 总被引:39,自引:2,他引:39
以NaOH,Na2CO3混合或以NH4OH,(NH4)2CO3混合液为沉淀制备了Mg/Al=3-6.7的Mg-Al为滑石。将水滑石在500-600℃下焙烧制得了具有与Mgo相同的晶体结构的Mg(Al)L复合氧化物,它们的比表面积大于或接近γ-Al2O3,而且具有良好的热稳定性。 相似文献
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Diblock and multiblock copolymers composed of a poly(D,L-lactide) (PLA) or poly(trimethylene carbonate) (PTMC) core with a hydrophilic chain of poly(ethylene glycol) (PEG) were prepared. These copolymers, in which the core is connected to PEG through a polyfunctional molecule such as citric, mucic, or tartaric acid, may be used to form nanoparticles for drug delivery applications. Branched copolymers were prepared by direct amidation between the polyfunctional acid and methoxy PEGamine, followed by ring-opening polymerization of lactide or trimethyl carbonate to form the PLA and PTMC block copolymers. In addition, a complex multiblock copolymer of biotin-PEG-poly[lactic-co-(glycolic acid)] (PLGA) for application in an avidin-biotin system was prepared for possible design of nanospheres with targeting properties. Studies of drug release from polymeric systems containing multiblock copolymers and studies of polymer degradation were also performed. 相似文献
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Sheykhan M Heydari A Ma'mani L Badiei A 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,83(1):379-383
Pure homogeneous nano sized biocompatible fluorapatite (FAp) particles were synthesized by a wet chemical procedure using water soluble tetra-butylammonium fluoride (TBAF) without using high temperatures and any purification processes. Combination of the Bragg's law and the plane-spacing equation for the two high intensity lines, namely, (002) and (300), gives a=9.3531 ?, c=6.8841 ?, confirms the identity of the highly crystalline synthetic material as well as its purity. The effect of various pH's in crystal formation and on their size was also evaluated. The calculated crystallinities were excellent with a rate around 5.0. The synthesized nano FAp was fully characterized by spectroscopic techniques (XRD, SEM, EDS, BET, FT-IR and ICP-AES). The nitrogen adsorption-desorption isotherm showed a type IV diagram and calculation of the surface area was investigated as well. 相似文献
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Shiva Tavakoli Sayed Ali Ahmadi Dadkhoda Ghazanfari Enayatollah Sheikhhosseini 《印度化学会志》2022,99(7):100561
In recent years, fullerene nanoparticles have received extensive attention due to their unique physical and chemical properties. Properly modified fullerene nanoparticles have excellent biocompatibility and significant anti-tumor activity and anti-depression, which makes them have broad application prospects in the field of cancer anti-depression. The present study used the density functional theory (DFT) calculations to perform a theoretical examination of the interaction of fluoxetine (F) as medicine with the functionalized fullerene O and NO (F–O and F–NO surface in gas phase physiological media. According to DFT calculations, adsorption energies were ?3396.6350645, ?3540.2952907, ?6778.526894, and ?6952.251487 kJ for F/P complexes (fullerene O and NO (F–O and F–NO surface) respectively, proposing the possibility of the adsorption process of F molecule onto the fullerene surface concerning the energetic perspective. Calculations of electronic parameters aimed at determining the molecule's reactivity. Bandgap of F–O and F–NO were 0.03715, 0.04328 respectively, by this value we can recognize the reactivity of complexes. 相似文献
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T. P. Shakhtshneider M. A. Vasilchenko A. A. Politov V. V. Boldyrev 《Journal of Thermal Analysis and Calorimetry》1997,48(3):491-501
The method of mechanical activation was used to obtain solid-state dispersions of some drugs in polyvinylpyrrolidone, polyethylene glycol and talc as carriers. Solid dispersions obtained by mechanical activation were found to have higher apparent solubilities and dissolution rates than mechanically activated drugs or their physical or eutectic mixtures with carriers used. It was shown by IR-spectroscopy and fluorescence measurements that mechanical treatment gave rise to an interaction between components which was apparently responsible for the solubilization effects observed. 相似文献
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Core–shell, Au–Pt bimetal nanoparticles were successfully synthesized by a simple two-step method. Ultraviolet–visible spectra
and transmission electron microscopy were used to characterize the nanoparticles. In the formation of Au-core/Pt-shell bimetal
nanoparticles, the poly(N-vinyl-2-pyrrolidone) replacement of citrate and the existence of H2C2O4 play key roles. 相似文献
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H.C. Clark S.S. McBride N.C. Payne C.S. Wong 《Journal of organometallic chemistry》1979,178(2):393-408
The reaction of [Pt((F3C)CCH(CF3))(P(C2H5)3)2CH3OH]PF6 with allene in methanol affords a novel metallocyclic ethereal complex [CH3)(P(C2H5)3)2]PF6, which has been characterized by 1H, 2H, 19F and 31P NMR spectroscopy. Its structure has also been determined by a single crystal X-ray analysis. The crystal are monoclinic, space group P21/n, with cell dimensions a 20.012(5), b 17.222(5), c 8.902(3) Å and β 91.54(5)°. The structure was refined by full matrix least-squares methods on F, using 3097 unique observations collected by automated four circle diffractometer. Refinement converged at R 0.066. The Pt atom has a distorted square-planar coordination geometry, with cis P atoms, and PtP distances of 2.219(4) Å (trans to O) and 2.324(4) Å (trans to C). These results show the ethereal group is a weak ligand to platinum(II) but because of the chelating effect, its displacement by other ligands is thermodynamically not favorable. The mechanism of formation of the ethereal complex is also discussed. 相似文献
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Guanylurea nitrate (GUN) and guanylurea perchlorate (GUP) were prepared from cyanoguanidine (CG) and concentrated nitric or perchloric acid, respectively. Both compounds were fully characterized by analytical and spectroscopic methods. Crystals of GUP were grown from water, and its crystal structure was determined by single‐crystal X‐ray diffraction. GUP crystallizes in the monoclinic space group P21/c with four molecules in the unit cell; different unit cell parameters are a = 8.0115(2) Å, b = 9.7328(2) Å c = 9.5770(2) Å and β = 105.89(1)°. The heats of combustion of both compounds were determined using oxygen bomb calori‐metry. Finally, the EXPLO5 computer code was used to determine the detonation velocity (D = 5734 m s−1) and pressure (P = 10.6 GPa) of GUN as well as those of formulations with ammonium nitrate and dinitramide. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:301–306, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20419 相似文献
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HanWen Sun LianYing Zhang XinJun Zhu ChunYan Kong CunLan Zhang SiDe Yao 《中国科学B辑(英文版)》2009,52(1):69-75
One-pot synthesis of magnetic nanogels with excellent biocompatibility via the photochemical method is reported in this paper.
Poly(PEGMA) modified superparamagnetic nanogels (poly(PEGMA) magnetic nanogels) were synthesized by in-situ polymerization using poly(ethylene glycol) methacrylate (PEGMA) as the monomer and N, N′-methylene-bis-(acrylamide) (MBA) as the cross-linking agent in magnetite aqueous suspension under UV irradiation. The surface
functional groups and components of magnetic nanogels were analyzed by Fourier transform infrared spectroscopy (FTIR) and
a thermogravimetric analyzer (TGA). The results indicated that the poly(PEGMA) magnetic nanogels were synthesized successfully
by coating poly(PEGMA) on the Fe3O4 nanoparticles under UV irradiation, and the Fe3O4 nanoparticles content in this nanogels was above 50 wt%. The morphology, size, zeta-potential and magnetic property were
also characterized. The magnetic nanogels had a nearly spherical shape and core-shell structure, the average size in aqueous
system measured by photon correlation spectroscopy (PCS) was 68.4 nm, which was much bigger than that in the dry state, the
nanogels behaved superparamagnetically with saturated magnetization of 58.6 emu/g, and the zeta-potential was −16.3–−17.3
mV at physiological pH (6.8–7.4) which could help to maintain stability in blood. The preliminary application as drug carrier
was made and the doxorubicin-loaded magnetic nanogels had an excellent property in slow-release. The experiment indicated
that the magnetic nanogel was an ideal candidate carrier in target drug delivery systems and other biomedical application.
Supported by the Natural Science Foundation of Shandong Province (Grant No. Q2006F01), Scientific and Technological Project
of Shandong Province (Grant No. 2007GG3WZ02066) and Scientific and Technological Project of Department of Education, Shandong
(Grant No. J07WC01) 相似文献
20.
M. Hussain M. Mazhara T. Hussainb N. A. Khan 《Journal of the Iranian Chemical Society》2010,7(2):S59-S69
Ultra fine thin films of pure and SnO doped ZnO nanosensor were grown on gold digitated ceramic substrate from bis(2, 4- pentanedionate)dimethylethanolamine zinc (II) using bis(2, 4-pentanedionate) tin(II) chloride as a dopant by ultrasonic aerosol assisted chemical vapor deposition technique (UAACVD) at temperature range of 400–450 °C under oxygen atmosphere at 5 Pa pressure. The sensitivity, selectivity, fast recovery, and reliability test performed on nanosensor suggested that both doped and undoped ZnO thin films are suitable for detecting ethanol vapor in the temperature range of at 60 to 150 °C, whereas at room temperature (25 °C) response and recovery time of the sensor increases many folds compared to 60 °C. Sensitivity of the ZnO sensor shows linear relationship with the increase of gas concentration. Electrical properties show that 1 % SnO doped ZnO enhanced the sensitivity of the film drastically and thus improved its detecting efficiency. Physico-chemical techniques like, CHNS-O, atomic absorption analyzer, and infra red and multinuclear nuclear magnetic resonance spectrometers were used for precursor characterization. X-ray diffractometer, scanning electron microscope, sigma scan analyzer and energy dispersive x-ray techniques were used for thin film characterization. 相似文献