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1.
Using cheap n‐butylamine as template, ZSM‐5 zeolites have been successfully synthesized and coated on monolithic interconnected macroporous Al2O3 by the secondary growth method. The use of cheap n‐butylamine could significantly reduce the synthesis cost. Hierarchical monolithic ZSM‐5 zeolites were prepared from synthetic mixtures with different H2O/Na2O or SiO2/Al2O3 ratio. The synthesized samples were characterized by scanning electron microscopy (SEM), X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FT‐IR) and N2 adsorption‐desorption. The results show that the hierarchical monolithic zeolites were obtained with cheap n‐butylamine template as template. During the hydrothermal reaction process, the morphology of the micrometer‐sized support was well maintained. The irregular crystals were formed in a wide range of the H2O/Na2O or SiO2/Al2O3 ratio of synthetic mixtures and coated on monolithic Al2O3. The relative crystallinity of the zeolites was highest at H2O/Na2O=250 or SiO2/Al2O3=160. This type of composites exhibited hierarchical porous structures and relatively high specific surface areas. 相似文献
2.
Glycosyl‐Templated Chiral Helix Stapling of Ethynylpyridine Oligomers by Alkene Metathesis between Inter‐Pitch Side Chains 下载免费PDF全文
Dr. Hajime Abe Dr. Fumihiro Kayamori Prof. Dr. Masahiko Inouye 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(26):9405-9413
Ethynylpyridine polymers and oligomers consisting of 4‐substituted pyridine rings linked by acetylene bonds at the 2‐ and 6‐positions have been investigated. Ethynylpyridine oligomers covalently linked with a glycosyl chiral template form chiral helical complexes by intramolecular hydrogen bonding, in which the chirality of the template is translated to the helix. With a view to fixation of the chiral architecture, D /L ‐galactosyl‐ and D /L ‐mannosyl‐linked ethynylpyridine oligomers have been developed with 4‐(3‐butenyloxy)pyridine units having alkene side chains. The helical structures are successfully stapled by alkene metathesis of the side chains. Subsequent removal of the chiral templates by acidolysis produces template‐free stapled oligomers. The chiral, template‐free, stapled oligomers show chiral helicity, which is resistant to polar solvents and heating. 相似文献
3.
线型脲醛树脂的半结晶模板化作用 总被引:2,自引:0,他引:2
酸性条件下硅溶胶体系中尿素和甲醛聚合反应会产生脲醛树脂-氧化硅杂化沉淀. 沉淀的质量随有机组分比例的增加而增加, 当尿素和甲醛物质的量比≥1.0时生成沉淀的量为恒定最大值. 红外分析表明杂化材料在3348, 1635, 1572和784 cm-1处产生了可被归结为线型结构(—[NHCONHCH2]n—)的特征吸收. XRD分析表明这种线型分子可形成氢键(C=O…H—N)导向型的半结晶. 微分热重和XRD结果证明结晶物种在290 ℃完全分解. SEM表征显示半结晶杂化沉淀以三维网络结构为特征, 具有层状结晶的各向异性, 其初级粒子即使在室温下干燥也容易开裂. 随着反应时间的延长、酸性的增加或无机组分量的相对增加杂化粒子变得更加致密. 液氮吸附结果证明沉淀焙烧后所得氧化硅材料的结构具有层状孔结构性质, 其比表面积、孔尺寸和孔体积可以达到510 m2/g, 14.3 nm和1.68 cm3/g. 改变反应体系的酸性和反应组分配比等条件可以方便地控制杂化材料的结构. 相似文献
4.
Considerable progress has been made in the prediction methods of 3D structures of RNAs. In contrast, no such methods are available for DNAs. The determination of 3D structures of the latter is also increasingly needed for understanding their functions and designing new DNA molecules. Since the number of experimental structures of DNA is limited at present, here, we propose a computational and template-based method, 3dDNA, which combines DNA and RNA template libraries to predict DNA 3D structures. It was benchmarked on three test sets with different numbers of chains, and the results show that 3dDNA can predict DNA 3D structures with a mean RMSD of about 2.36 Å for those with one or two chains and fewer than 4 Å with three or more chains. 相似文献
5.
Alexander Marin Marc B. Taraban Vanshika Patel Y. Bruce Yu Alexander K. Andrianov 《Molecules (Basel, Switzerland)》2022,27(21)
The in vivo potency of polyphosphazene immunoadjuvants is inherently linked to the ability of these ionic macromolecules to assemble with antigenic proteins in aqueous solutions and form physiologically stable supramolecular complexes. Therefore, in-depth knowledge of interactions in this biologically relevant system is a prerequisite for a better understanding of mechanism of immunoadjuvant activity. Present study explores a self-assembly of polyphosphazene immunoadjuvant—PCPP and a model antigen—lysozyme in a physiologically relevant environment—saline solution and neutral pH. Three analytical techniques were employed to characterize reaction thermodynamics, water-solute structural organization, and supramolecular dimensions: isothermal titration calorimetry (ITC), water proton nuclear magnetic resonance (wNMR), and dynamic light scattering (DLS). The formation of lysozyme–PCPP complexes at near physiological conditions was detected by all methods and the avidity was modulated by a physical state and dimensions of the assemblies. Thermodynamic analysis revealed the dissociation constant in micromolar range and the dominance of enthalpy factor in interactions, which is in line with previously suggested model of protein charge anisotropy and small persistence length of the polymer favoring the formation of high affinity complexes. The paper reports advantageous use of wNMR method for studying protein-polymer interactions, especially for low protein-load complexes. 相似文献
7.
采用聚苯乙烯(PS)空心微球为模板,间苯二酚-甲醛(RF)为前驱体溶液,邻苯二甲酸二丁酯为分散剂,以界面聚合反应为基础初步总结出一条PS-RF双层聚合物空心微球的制备工艺,并就制备过程中RF溶液与分散剂油相的选择、预聚时间、搅拌速率、固化温度等影响因素进行了讨论。当RF溶液质量分数为25%,间苯二酚与碳酸钠的物质的量之比为100,预聚24 h,搅拌速率120~200 r/min,固化温度35 ℃时,制得了球形度和同心度达到95%以上,表面粗糙度小于10 nm的PS-RF双层空心微球。 相似文献
8.
The interactions between Trichoderma reesei cellulase and an anionic surfactant, sodium dodecyl sulfate (SDS), at critical micelle concentration level have been investigated using isothermal titration calorimetry, fluorescence spectroscopy, and circular dichroism. SDS micelles have dual interactions with cellulase: electrostatic at first and then hydrophobic interactions. When the concentration of SDS is smaller than 45.0 mM, SDS micelles cause a partial loss in the hydrolytic activity together with a steep decrease in the -helical content of cellulase. With further increasing the concentration of SDS, however, a re-formation of the -helical structure and a partial recovery of the hydrolytic activity of cellulase induced by SDS micelles are observed. Taken together, these results indicate that SDS micelles exert dual effects on cellulase through binding as both a denaturant and a recovery reagent. 相似文献
9.
《Analytical letters》2012,45(10):709-720
Abstract The performance of a liquid-membrane electrode using a synthetic, neutral carrier in o-nitro-phenyl-n-octyl-ether as membrane component in a PVC matrix, in the presence of sodium tetra-phenyl-borate, is described. Selectivities, working range, lifetime and anion interference are discussed. The electrode makes possible the measurement of calcium ion activities in the range 10?1M to 10?6M in unbuffered and in the range 10?1M to 10?8M in calcium buffered systems respectively. The selectivities of calcium over protons, magnesium, sodium and zinc are 25,000, 26,000, 2,800 and 7,100, respectively, and are far superior than those reported for other calcium sensors. 相似文献
10.
利用磁过滤等离子体结合氧化铝模板(AA0)技术在室温下制备了具有优异场发射性能的铜掺杂类金刚石(DLC)纳米点阵列.微观分析表明,铜掺杂类金刚石纳米点阵列分布均匀,密度高达109cm-2;利用X射线光电子能谱对制备的铜掺杂类金刚石纳米点阵列进行结构分析,测得铜的掺杂量为3.6;且sp3键含量高达60;;通过对铜掺杂类金刚石纳米点阵列的场发射性能测试,试验结果表明,铜掺杂类金刚石纳米点阵列开启电场和阈值电场分别为0.08V/μm,0.42V/μm,并且在电场值为0.67V/μm时,发射电流密度高达95mA/cm2,场发射性能明显优于无掺杂类金刚石纳米点阵列. 相似文献