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991.
Mesoporous carbon catalyst supports are attractive due to their wide chemical stability while potentially increasing mass-transport through and providing a path for larger molecules to access catalytic sites. Herein we report the synthesis of a phosphorylated mesoporous carbon solid-acid catalyst characterized by NH(3)-TPD and isopropanol dehydration. 相似文献
992.
Guo J Baker GA Hillesheim PC Dai S Shaw RW Mahurin SM 《Physical chemistry chemical physics : PCCP》2011,13(27):12395-12398
In this work, we provide new experimental evidence for chain length-dependent self-aggregation in room temperature ionic liquids (RTILs) using fluorescence correlation spectroscopy (FCS). In studying a homologous series of N-alkyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl) imide, [C(n)MPy][Tf(2)N] RTILs of varying alkyl chain length (n = 3, 4, 6, 8, and 10), biphasic rhodamine 6G solute diffusion dynamics were observed; both the fast and slow diffusion coefficients decreased with increasing alkyl chain length, with the relative contribution from slower diffusion increasing for longer-chain [C(n)MPy][Tf(2)N]. We propose that the biphasic diffusion dynamics originate from self-aggregation of the nonpolar alkyl chains in the cationic [C(n)MPy](+). 相似文献
993.
Gui‐Ge Hou Li‐Ying Ma Xian‐Ping Dai 《Acta Crystallographica. Section C, Structural Chemistry》2011,67(10):m321-m323
The title compound, [Zn(C9H7N3)2(H2O)4](CF3O3S)2, contains an octahedral [ZnL2(H2O)4]2+ cationic complex with trans geometry (Zn site symmetry ), and each 5‐(3‐pyridyl)pyrimidine (L) ligand is coordinated in a monodentate fashion through the pyridine N atom. In the extended structure, these complexes, with both hydrogen‐bond acceptor (pyrimidine) and donor (H2O) functions, are linked to each other by intermolecular water–pyrimidine O—H...N hydrogen‐bonding interactions, resulting in a double chain along the crystallographic a axis. The trifluoromethanesulfonate anions are integrated into the chains via O—H...O hydrogen bonds between the coordinated water and sulfonate O atoms. These double chains are associated into a novel three‐dimensional network through interchain water–pyrimidine O—H...N hydrogen bonds. The asymmetric ligand plays an important role in constructing this unusual supramolecular structure. 相似文献
994.
提出了以圆筒扭转力学模型为基础, 预测周期性多孔材料等效剪切模量及其研究尺寸效
应的一种简单有效计算方法. 以方形孔和圆形孔两种典型多孔材料为例进行了数值计算求解;
同时, 建立了几何参数随体胞尺寸缩放因子$n$的解析关系, 证明了两种构型的周期性多孔材
料的等效剪切模量均随尺寸缩放因子$n$的增大而减小. 当$n \to \infty
$时, 即体胞尺寸相对整体结构无限小时, 多孔材料的等效剪切模量趋近收敛于一个恒定值;
当体胞的材料体分比增大时, 多孔材料等效剪切模量也随之增大. 此外, 依据周
期性多孔材料的结构对称特性, 使用体胞子结构有限元计算模型进行等效剪切模量及其尺寸
效应的预测, 极大地提高了计算效率. 相似文献
995.
Yucheng Du a Shuli Shi a Hong He b Hongxing Dai b a Key Laboratory of Advanced Functional Materials Ministry of Education Beijing University of Technology Beijing China b 《中国颗粒学报》2011,9(1)
Nanorod-like Ce 0.7 Zr 0.3 O 2 solid solutions were synthesized by a sodium dodecyl sulfate-assisted precipi- tation method. The samples were characterized by means of scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and specific surface area measurement. Typical Ce 0.7 Zr 0.3 O 2 nanorods were 40 nm in average diameter and 450 nm in length, with specific surface area and oxygen storage capacity of 194 m 2 /g and 374 mol/g, respectiv... 相似文献
996.
997.
Highly Conductive Microfiber of Graphene Oxide Templated Carbonization of Nanofibrillated Cellulose 下载免费PDF全文
Fei Shen Jiayu Wan Xiaogang Han Jiaqi Dai Hongqi Dai Liangbing Hu 《Advanced functional materials》2014,24(46):7366-7372
Microfibers with conductivity of 649 ± 60 S/cm are introduced through a carbonization of well‐aligned graphene oxide (GO) – nanofibrillated cellulose (NFC) hybrid fibers. GO acts as a template for NFC carbonization, which changes the morphology of carbonized NFC from microspheres to sheets while improving the carbonization of NFC. Meanwhile, the carbonized NFC repairs the defects of reduced GO (rGO) and links rGO sheets together. The GO templated carbonization of NFC as well as the alignment of the building blocks along the fiber direction leads to excellent conductivity. Conductive microfibers are evaluated as lithium ion battery anodes, which can be applied in wearable electronics. This approach to make conductive microfibers and the low cost raw materials used in this work may be applied to other carbon based conductive structures. 相似文献
998.
Dandan Zheng Mingang Hua Junfeng Chen Cunkang Bian Weili Dai 《Mathematical Methods in the Applied Sciences》2019,42(3):982-998
This paper studies the robust partially mode‐dependent H∞ filtering for nonhomogeneous Markovian jump neural networks with additive gain perturbations. The discrete time‐varying jump transition probability matrix is considered to be a polytope set. A partially mode‐dependent filter with additive gain perturbations is constructed to increase the robustness of the filter, which is subjects to H∞ performance index. Based on the Lyapunov function approach, sufficient conditions are established such that the filtering error system is robustly stochastically stable. The efficiency of the new technique is illustrated by an illustrative example and a biological network example. 相似文献
999.
This paper is concerned with the spreading and vanishing phenomena in a diffusive intraguild (IG) predation model with intraspecific competition and free boundary in one dimensional space. The main objective is to obtain the asymptotic behavior of spread of an invasive or new IG prey species via a free boundary. In two cases, we prove a spreading‐vanishing dichotomy for this model, specifically, the IG prey species either successfully spreads to infinity as t→∞ at the front and survives in the new environment or spreads within a bounded area and dies out in the long run. The long time behavior of (R,N,P) and criteria for spreading and vanishing are also obtained. And then, we estimate the asymptotic spreading speed of the free boundary when spreading happens. Besides, two numerical examples are given to illustrate the impacts of initial occupying area and expanding capability on the free boundary. 相似文献
1000.
Ultrasmall Graphene Oxide Supported Gold Nanoparticles as Adjuvants Improve Humoral and Cellular Immunity in Mice 下载免费PDF全文
Yuhua Cao Yufei Ma Mengxin Zhang Haiming Wang Xiaolong Tu He Shen Jianwu Dai Huichen Guo Zhijun Zhang 《Advanced functional materials》2014,24(44):6963-6971
Adjuvants play an important role in vaccines. Alum and MF59 are two dominant kinds of adjuvants used in humans. Both of them, however, have limited capacity to generate the cellular immune response required for vaccines against cancers and viral diseases. It is desirable to develop new and efficient adjuvants with the aim of improving the cellular immune response against the antigen. Here, the feasibility and efficiency of ultrasmall graphene oxide supported gold nanoparticles (usGO‐Au) as a new immune adjuvant to improve immune responses are explored. usGO‐Au is obtained from reduction of chloroauric acid using usGO and then decorated with ovalbumin (OVA, a model antigen) through physical adsorption to construct usGO‐Au@OVA. As the results show, the as‐synthesized usGO‐Au@OVA can efficiently stimulate RAW264.7 cells to secrete tumor necrosis factor‐α (TNF‐α), a mediator for cellular immune response. In vivo studies demonstrate that usGO‐Au@OVA can also promote robust OVA specific antibody response, CD8+ T cells proliferation, and different cytokines secretion. The results indicate that using usGO‐Au as an adjuvant can stimulate potent humoral and cellular immune responses against antigens, which may promote better understanding of cellular immune response and facilitate potential applications for cancer and viral vaccines. 相似文献