γ-Al2O3柔性纳米纤维膜的制备及机械性能

以氯化铝和异丙醇铝为原料, 水和乙醇为溶剂, 通过溶胶凝胶结合静电纺丝法制备了柔性γ-Al2O3纳米纤维膜.表征了纤维膜的形貌和机械性质, 并研究了纤维膜的形成过程.组成纤维膜的纤维直径均匀, 平均直径188 nm, 纤维由粒径在15~30 nm的纳米颗粒组成且表面光滑.制备的纤维膜具有较好的柔性及抗拉强度(1.01 MPa).     

γ-Al_2O_3柔性纳米纤维膜的制备及机械性能（英文）

以氯化铝和异丙醇铝为原料,水和乙醇为溶剂,通过溶胶凝胶结合静电纺丝法制备了柔性γ-Al_2O_3纳米纤维膜.表征了纤维膜的形貌和机械性质,并研究了纤维膜的形成过程.组成纤维膜的纤维直径均匀,平均直径188 nm,纤维由粒径在15~30 nm的纳米颗粒组成且表面光滑.制备的纤维膜具有较好的柔性及抗拉强度(1.01 MPa).     

柔性透明自支撑氧化锡锑电纺纳米纤维膜的制备与表征

以四氯化锡和三氯化锑为前驱体,通过静电纺丝技术制备了柔性透明的自支撑氧化锡锑(ATO)纳米纤维膜.研究结果表明,该柔性ATO纤维膜具有四方相金红石晶体结构,且呈无规的纤维网状分布.当前驱体煅烧温度分别为520℃和700℃时,纤维的平均直径为200和150 nm;组成纤维的颗粒的平均粒径为10和19 nm;可见光透过率为72%和80%;电阻率为5.23和2.20Ω·cm.该自支撑ATO纳米纤维膜还显示出优异的柔韧性,在弯曲500次后其电阻率基本不变.     

在一种新的溶剂体系中通过静电纺丝制备TiO2纳米纤维

以钛酸四丁酯为前驱体, 醋酸纤维素为模板纤维, 丙酮/N,N-二甲基乙酰胺为溶剂, 通过静电纺丝, 水解和450 ℃煅烧制备了直径约为80 nm的锐钛矿型TiO₂纳米纤维. 通过扫描电镜(SEM)、透射电镜(TEM)、X射线衍射(XRD)和N₂吸脱附法表征了TiO₂纳米纤维的形貌、直径大小、晶态、比表面积、孔结构及分布. 研究表明该纳米纤维由大小为9.2 nm的颗粒组成, 纤维内含有大量直径为1.7～21 nm的介孔. 它具有与直径为25 nm的商业化Degussa P25相似的高比表面积, 约为50 m²/g. 研究了TiO₂纳米纤维对有机小分子化合物罗丹明B (RhB)和苯酚的光催化降解. 结果表明: 以6 mg/L的RhB和10 mg/L的苯酚水溶液为母液, 以质量分数为0.05%的TiO₂纳米纤维膜为催化剂, 在500 W的紫外灯照射下, 2 h内约90%的RhB和75%的苯酚能被光催化降解.     

γ-Fe2O3纳米纤维的丙酮敏感特性

采用静电纺丝法制备了PVP/FeC₆H₅O₇复合纳米纤维, 并将复合纤维在500 ℃高温烧结3 h, X射线衍射分析(XRD)表明, 烧结后的产物为正尖晶石结构的γ-Fe₂O₃晶体. 扫描电子显微镜(SEM)观测结果表明, 制得了直径均匀、 连续的复合纳米纤维, 其平均直径约为1000 nm; 烧结后的γ-Fe₂O₃纳米纤维保持了其连续性, 但纤维发生了收缩, 直径较烧结前小, 平均约为600 nm. 比表面积分析表明, γ-Fe₂O₃纳米纤维比表面积为57.18 m²/g. 气敏性能测试结果表明, 230 ℃为γ-Fe₂O₃纳米纤维检测丙酮气体的最佳工作温度. 在此温度下, γ-Fe₂O₃纳米纤维对丙酮气体表现出高响应度[S=6.9, c(Acetone)=7.88×10⁴ mg/m³]和线性度(7.88×10²~1.58×10⁵ mg/m³浓度范围内). 同时, γ-Fe₂O₃纳米纤维气体传感器件还表现出良好的长期稳定性.     

高透明的柔性金纳米纤维膜

通过静电纺丝技术与离子溅射镀膜法,以电纺聚乙烯吡咯烷酮(PVP)为模板,制备了高透明的柔性金(Au)纳米纤维膜.研究表明,该柔性Au纳米纤维膜呈现无规网状分布,纤维的平均直径为291~322 nm.当Au的溅射时间为75 s时,所得薄膜的可见光透过率为92%,近红外反射率为7%,电阻率为2.9×10-3Ω·cm.该Au纳米纤维膜可转移到任何柔性基底上,且显示出优异的柔韧性,在弯曲500次后其电阻率基本不变.     

YF3:Eu3+纳米纤维/高分子复合纳米纤维的制备与表征

采用静电纺丝技术制备了Y2O3:Eu3+纳米纤维,使用NH4HF2为氟化剂,经双坩埚法氟化和脱氨后得到YF3:Eu3+纳米纤维,再采用静电纺丝技术制备了YF3:Eu3+纳米纤维/PVP复合纳米纤维. XRD分析表明,立方相的Y2O3:Eu3+氟化后,得到了正交相的YF3:Eu3+纳米纤维,空间群为Pnma;YF3:Eu3+纳米纤维/PVP复合纳米纤维具有明显的YF3:Eu3+的衍射峰. SEM分析表明,YF3:Eu3+纳米纤维与YF3:Eu3+纳米纤维/PVP复合纳米纤维的直径分别为91±11 nm、319±43 nm,表面光滑. 用Shapiro-Wilk方法检验,纤维直径属于正态分布. 荧光光谱分析表明,YF3:Eu3+纳米纤维和YF3:Eu3+纳米纤维/PVP复合纳米纤维的最强发射峰均位于588 nm和595 nm,属于Eu3+的5D0→7F1跃迁,表明Eu3+占据YF3基质中Y3+晶格点的C2对称格位. PVP对YF3:Eu3+发光峰位没有影响,但发光强度降低;YF3:Eu3+的含量与YF3:Eu3+纳米纤维/PVP复合纳米纤维的发光强度成线性关系.     

Ag/AgCl复合纳米粒子/聚丙烯腈纳米纤维膜的制备及可见光催化降解甲基橙

通过电纺丝法结合原位还原及原位氧化反应, 成功制备了均匀负载Ag/AgCl复合纳米粒子/聚丙烯腈(PAN)复合纳米纤维膜. 首先利用电纺丝技术制备了PAN/AgNO₃复合纳米纤维, 然后用乙二醇将硝酸银还原成银纳米粒子, 最后采用三氯化铁溶液对材料进行原位氧化. 所得纤维膜材料可以作为高效的可见光催化剂, 具有高可见光利用率, 优异的柔性和高光催化动力学等特性.     

静电纺丝法制备SrTiO3多晶微纳米纤维

应用静电纺丝法并结合Sol-gel 技术制备了SrTiO3微纳米纤维. SEM, TEM及电子衍射分析结果显示, 于900 ℃煅烧获得的纤维直径分布在50~400 nm之间, 其典型直径约为280 nm. XRD分析结果表明, 纤维由立方结构的SrTiO3晶粒组成, 平均晶粒尺寸为33 nm.     

EVOH纳米纤维及其功能膜的制备与性能研究北大核心CSCD

利用熔融纺丝相分离行为制备乙烯-乙烯醇共聚树脂(EVOH)纳米纤维,并利用湿法成网的方法制备EVOH纳米纤维膜,分析表征了EVOH纳米纤维的形态、结构、结晶性能及纤维膜的形态、孔隙率、孔径大小和分布、比表面积等。结果表明:乙烯-乙烯醇共聚树脂/乙酸丁酸纤维素酯(EVOH/CAB)经双螺杆熔融挤出去除CAB后所制备的EVOH纳米纤维平均直径为162～260nm,加工条件和方法对EVOH的结构和结晶性能没有明显影响。随着纤维膜厚度增加,EVOH纳米纤维膜的孔径减小、孔径分布变窄;随着纳米纤维制备过程中EVOH/CAB体系中EVOH含量增大,EVOH纳米纤维直径增大,其功能膜的孔隙率增大、比表面积减小。     

Al源种类对微乳液法制备固体超强酸催化剂异构化性能的影响

分别以拟薄水铝石、γ-Al₂O₃、Al₂O₃、Al(NO₃)₃·9H₂O为Al源,通过微乳液法制备了一系列Pt-S₂₈O^2-/ZrO₂-Al₂O₃催化剂,并利用XRD、FT-IR、BET、H₂-TPR等手段对其进行了表征,考察了Al源种类对Pt-S₂₈O^2-/ZrO₂-Al₂O₃固体超强酸催化剂结构和酸性的影响,并以正戊烷异构化反应为探针,考察了Al源种类对催化剂异构化性能的影响。结果表明,不同Al源制备的催化剂均能够稳定ZrO₂四方晶相,增大催化剂的比表面积;除以拟薄水铝石为Al源制备的催化剂外,其他催化剂的氧化还原性能均有所提高。以Al(NO₃)₃·9H₂O为Al源制备的催化剂具有最大的比表面积和更多的超强酸,表现出最佳的异构化性能,在反应压力2.0 MPa、氢烃物质的量比4∶1、质量空速(WHSV)1.0 h^-1、反应温度220 ℃条件下,异戊烷产率达到59.5%。     

铝源对Ni/Al2 O3催化剂结构及其CO2-CH4重整性能的影响

以三种不同铝源采用溶液燃烧法制备了系列Ni/Al_2O_3催化剂,通过XRD、H_2-TPR、NH_3-TPD、N_2吸附-脱附、TGDTG和TPH等分析方法对反应前后催化剂进行了表征,研究了铝源对Ni/Al_2O_3催化剂结构、表面性质及其CO_2-CH_4重整性能的影响。结果表明,以Al(NO_3)_3·9H_2O为铝源制备的NiNO-AlNO催化剂比表面积较大,达102 m~2/g;高温还原峰面积大,峰型更为弥散;且载体Al_2_O_3具有一定的结晶性。而以Al_2(SO_4)_3·18H_2O和AlCl_3·6H_2O为铝源制备的NiNO-AlSO和NiNO-AlCl催化剂,其载体以无定型Al_2O_3存在,活性组分Ni晶粒粒径大、分散性差,还原峰面积较小,与载体的相互作用较弱。其中,由于硫酸铝较为稳定,需要在更高温度下才能转化为Al_2O_3,且所制备NiNO-AlSO催化剂中残留有含硫物质,使得其表面酸性较强。评价结果显示,NiNO-AlNO催化剂活性较高,稳定性好,CH4转化率为31.21%,CO_2转化率为48.97%。积炭分析结果发现,NiNO-AlNO催化剂表面积炭量最少,沉积炭主要以无定型态存在,具有良好的抗积炭性能。     

High-temperature High-pressure Hydrothermal Synthesis of Dy3＋-doped YNbO4 Single Crystal and Its Luminescence Properties

Single crystal Dy3＋ doped YNbO4phosphors were prepared via a high-temperature high-pressure hydrothermal procedure. Under excitation at 270 nm, the Dy3＋-doped YNbO4 phosphor shows bright white emission, which is composed of two strong bands at 492 and 576 nm corresponding to the characteristic 4F9/2→6H15/2 and aF9/2→6H13/2 transitions of Dy3＋, respectively. The dominant band was observed at 352 nm, which corresponds to the 6H15/2→6p7/2 transition of Dy3＋. Nearly white light was achieved at 2ex 270, 310 and 388 nm and the CIE（International Commission on Illumination） values were （0.3135, 0.3421）, （0.3088, 0.3380） and （0.3146, 0.3296）, respectively.     

Preparation and characterization of silicalite-1 membranes prepared by secondary growth of seeds with different crystal sizes

MFI-type zeolite particles of 0.1–1 μm in diameter were prepared by adjusting tetra-n-propylammonium hydroxide (TPAOH) and water contents in synthesis mixtures. Using those particles as seeds, MFI-type zeolite membranes were prepared on the surface of a porous mullite tube by secondary growth. The membranes were formed as polycrystalline zeolite layers on and inside the porous support, and the membranes were composed of the [h 0 h]-oriented crystallites. The membrane consisting of a-oriented crystallites could be also prepared. However, the a-oriented zeolite layers were not active on the permeation properties of butanes. Rather the size and loaded amount of the seed particles influenced on the permeation properties through the membranes. As a result, the n-C₄H₁₀/i-C₄H₁₀ permselectivity could be increased to 220 by adjusting the size and the loaded amount of particles. These results suggest that the number of loaded particles affects on the permeation properties through the membranes.     

Bio-ceramic hollow fiber membranes for immunoisolation and gene delivery: I: Membrane development

Zirconia bio-ceramic hollow fiber membranes were developed using a sequence of mixing, extrusion, phase inversion and sintering steps. ZrO₂ partially stabilized by Y₂O₃ was chosen as the starting membrane material. The prepared membranes were characterized by SEM, EDX, XRD and gas permeation techniques. Effects of the starting ZrO₂ particle size and sintering temperature on the physical properties of the resulted hollow fiber membranes were extensively studied. Sintered at 1400 °C for 10 h, membranes made from 80 nm sized ZrO₂ particles display cubic fluorite as the major crystalline phase and give rise to interesting microstructure for cell response. Without any surface modification, this tailor-made membrane with high mechanical strength and pore size less than 1 μm was selected for further test of osteoblast attachment. In vitro bio-compatibility was evaluated by using mouse MC-3T3-E1 osteoblast cell culture. A series of cell interactions with fiber surface (i.e. cell adhesion, proliferation, formation of bone nodules, mineralization, etc.) verified the bio-compatibility of the prepared membranes.     

六棱柱状多晶γ-Al2O3的制备、表征及其形成机制研究

以AlCl₃·6H₂O为前驱物,在氨水介质中用水热法制备了具有新颖形貌特征的六棱柱状多晶γ-Al₂O₃颗粒。采用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)及N₂物理吸脱附等方法对所制备的γ-Al₂O₃颗粒进行了表征,并对其形貌形成机制进行了分析。结果表明,铝前驱物在氨水介质中通过水热处理后,经焙烧可以形成形貌规整的六棱柱状γ-Al₂O₃颗粒,其边长与长度分别约为0.3 μm和2.5 μm。TEM图片显示,六棱柱颗粒是由尺寸在10 nm左右的粒子聚集而成,因而具有多晶γ相特征。所制备的γ-Al₂O₃材料具有发达的孔隙结构,比表面积为274 cm²/g,孔容为0.51 cm³/g,孔径集中分布在5.5 nm周围。研究发现,γ-Al₂O₃六棱柱形貌的形成机制与AlOOH二次粒子在NH₄⁺正电荷作用下发生的最稳态排列形式具有密切的关联。     

Preparation of water and alkali durable porous glass membrane coated on porous alumina tubing by sol-gel method

Composite porous glass membranes were prepared by the sol-gel method. A thin porous glass layer, about 2 μm thick, was coated on the surface of the porous ceramic tubing (Al₂O₃:99.9 wt.%, pore diameter: 200 nm). The composition of the porous glass layer of the composite membrane was SiO₂-ZrO₂. Considering from the fact that the desalination ratio of the feed aqueous NaCl solution (NaCl 0.5 wt.%) was about 90% by use of these membranes, they were defect-free. The best composition of the porous glass layer was 70 SiO₂-30 ZrO₂ from the standpoint of preparing membranes. These membranes had a large water and alkali durability. These membranes can be expected to apply to recovering dyes and paints from organic solvents and to be used as a gas separation membrane.     

Preparation of YSZ Microporous Membranes on Porous a-Alumina with Metal Chlorides as Precursor

A sol-gel process for YSZ membrane prepared with less expensive chemicals, ZrOCI₂·8H₂0 and YC1₃, has been developed. The sol viscosity as a function of concentration, acidity and temperature was brane formation processes were also studied. investigated. And gelation and Based on an optimized procedure memhole and crack-free YSZ membranes with the pore size less than 100 nm have obtained on coarse porous a-alumina.     

PHOTOBLEACHING OF A CYANINE DYE IN SOLUTION AND IN MEMBRANES

Abstract— N,N'-bis(2-ethyl-1,3-dioxolane)-kryptocyanine (EDKC), a lipophilic dye with a delocalized positive charge, photosensitizes cells to visible irradiation. In phosphate-buffered saline (PBS), EDKC absorbs maximally at 700 nm (ε= 1.2 × 10⁵ M⁻¹ cm⁻¹) and in methanol, the absorption maximum is at 706 nm (ε= 2.3 × 10⁵ M⁻¹ cm⁻¹). EDKC partitions from PBS into small unilamellar liposomes prepared from saturated phospholipids and into membranes prepared from red blood cells (RBC) and binds to human serum albumin (HSA). The EDKC fluorescence maximum red shifts from 713 nm in PBS to 720–725 nm in liposomes and RBC membranes and the fluorescence intensity is enhanced by factors of 14–35 compared to PBS (φ= 0.0046). EDKC is thermally unstable in PBS (T_1/2= 2 h at 1.3 × 10⁻⁵ M EDKC), but stable in methanol. In liposomes and RBC membranes, EDKC is 10 times more stable than in PBS, indicating that it is only partially exposed to the aqueous phase. Quenching of EDKC fluorescence in liposomes and RBC membranes by trinitrobenzene sulfonate also indicates that EDKC is not buried within the membranes. Photodecomposition of EDKC was oxygen-dependent and occurred with a low quantum yield (6.4 × 10⁻⁴ in PBS). Singlet oxygen was not detected upon irradiation of EDKC in membranes or with HSA since the self-sensitized oxidation of EDKC occurred at the same rate in D₂O as in H₂O and was not quenched by sodium azide or histidine.