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921.
Multiscale aspects of heat and mass transfer during drying 总被引:1,自引:0,他引:1
Patrick Perré 《Transport in Porous Media》2007,66(1-2):59-76
The macroscopic formulation of coupled heat and mass transfer has been widely used during the past two decades to model and
simulate the drying of one single piece of product, including the case of internal vaporization. However, more often than
expected, the macroscopic approach fails and several scales have to be considered at the same time. This paper is devoted
to multiscale approaches to transfer in porous media, with particular attention to drying. The change of scale, namely homogenization,
is presented first and used as a generic approach able to supply parameter values to the macroscopic formulation. The need
for a real multiscale approach is then exemplified by some experimental observations. Such an approach is required as soon
as thermodynamic equilibrium is not ensured at the microscopic scale. A stepwise presentation is proposed to formulate such
situations. 相似文献
922.
采用双波长高效液相色谱法同时测定对二甲苯及其氧化产物的含量。通过二极管阵列检测器进行光谱扫描,选择在210nm下检测对甲基苯甲醇和对二甲苯,在254nm检测其余物质。优化了流动相及其梯度洗脱程序,将流动相乙腈比例降至20%~30%,各色谱峰能实现较好的分离。采用液相色谱法和气相色谱-质谱法研究了溶剂对对羧基苯甲醛和对甲基苯甲醛的影响。对羧基苯甲醛和对甲基苯甲醛可与溶剂甲醇反应生成缩醛。方法的检出限(3S/N)为0.07~0.8mg·L-1。各物质的回收率在99.2%~100%之间,相对标准偏差(n=6)小于2.5%。 相似文献
923.
Poly(glycidyl methacrylate‐co‐N‐methylolacrylamide‐co‐ethylene dimethacrylate) monolith coupled to high‐performance liquid chromatography for the determination of adenosine phosphates in royal jelly
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A polymer monolith microextraction method coupled with high‐performance liquid chromatography was developed for the determination of adenosine triphosphate, adenosine diphosphate, and adenosine monophosphate. The monolithic column was synthesized inside fused‐silica capillaries using thermal initiation free‐radical polymerization with glycidyl methacrylate as the monomer, ethylene dimethacrylate as the cross‐linker, cyclohexanol, and 1‐dodecanol as the porogen. N‐Methylolacrylamide, an important hydrophilic monomer, was incorporated into the polymerization mixture to enhance the hydrophilicity of the poly(glycidyl methacrylate‐co‐ethylene dimethacrylate) column. The obtained poly(glycidyl methacrylate‐co‐N‐methylolacrylamide‐co‐ethylene dimethacrylate) monolith was characterized by scanning electron microscopy, Fourier‐transform infrared spectra, and X‐ray photoelectron spectroscopy. Optimum conditions for the preconcentration and separation of the target adenosines were also investigated. Under the optimum conditions, we obtained acceptable linearities, low limits of detection, and good relative standard deviations. The developed polymer monolith microextraction with high‐performance liquid chromatography method exhibited a good performance with recovery values in the range of 76.9?104.7% when applied to the determination of the adenosines in five royal jelly samples. 相似文献
924.
Chih‐Hui Yang Chih‐Yu Wang Alexandru Mihai Grumezescu Andrew H.‐J. Wang Ching‐Ju Hsiao Zu‐Yu Chen Keng‐Shiang Huang 《Electrophoresis》2014,35(18):2673-2680
We report dual pH‐responsive microcapsules manufactured by combining electrostatic droplets (ESD) and microfluidic droplets (MFD) techniques to produce monodisperse core (alginate)‐shell (chitosan) structure with dual pH‐responsive drug release function. The fabricated core‐shell microcapsules were size controllable by tuning the synthesis parameters of the ESD and MFD systems, and were responsive in both acidic and alkaline environment, We used two model drugs (ampicillin loaded in the chitosan shell and diclofenac loaded in the alginate core) for drug delivery study. The results show that core‐shell structure microcapsules have better drug release efficiency than respective core or shell particles. A biocompatibility test showed that the core‐shell structure microcapsules presented positive cell viability (above 80%) when evaluated by the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay. The results indicate that the synthesized core‐shell microcapsules were a potential candidate of dual‐drug carriers. 相似文献
925.
Progressive functions at time t involve only the progressive functions at time before t and some nice compactly supported function at time t. We give sufficient conditions and explicit formulas to construct progressive functions with exponential decay and characterize the conditions on which the positive integer translates of a progressive function are orthonormal or a Riesz sequence. We provide explicit ways for construction of orthonormal progressive functions and for construction of the biorthogonal functions of nonorthogonal progressive functions. Such progressive functions can be used to construct wavelets with arbitrary smoothness on the half line if they are generated by a smooth refinable compactly supported function. 相似文献
926.
In this paper, the authors define a harmonic Orlicz combination and a dual
Orlicz mixed volume of star bodies, and then establish the dual
Orlicz-Minkowski mixed-volume inequality and the dual
Orlicz-Brunn-Minkowksi inequality. 相似文献
927.
神经元轴突分化和生长等行为受到物理和化学梯度调控。本文通过调节纳米金和基底之间的静电作用及化学因子在基底上的吸附,在玻璃基底上构建了高分辨率的纳米金密度梯度及物理-化学双重梯度,用来研究海马神经元轴突导向和生长规律。统计结果显示,轴突更倾向沿着纳米金密度增加的方向生长,表明纳米金密度梯度对轴突生长具有导向作用。引入化学因子梯度后,神经元轴突分化及生长等行为受到物理-化学梯度协同调控。本文建立的方法及研究结果可望为神经元发育和修复研究提供重要信息以及有力的工具。 相似文献
928.
S. R. K. Vedula T. S. Lim P. J. Kausalya E. B. Lane G. Rajagopal W. Hunziker C. T. Lim 《Experimental Mechanics》2009,49(1):3-9
Cellular adhesion and barriers formed by intercellular adhesion proteins [tight junctions (occludin and claudins) and adherens
junction (E-cadherin)] are important in maintaining tissue homeostasis. However, disruption of these junction proteins is
associated with diseases in the organ systems such as multiple sclerosis, diarrhea, asthma, and gastro-intestinal tract carcinomas
among others. In this paper, the separation force needed to separate two cells expressing some of these proteins was measured
using the dual micropipette assay. Results show that L-fibroblasts transfected with claudin-1 and claudin-2 exhibit higher
separation force (~2.8 nN and 2.3 nN, respectively) as compared to control cells or cells transfected with occludin (~1 nN).
Furthermore, the separation force was not affected on addition of calcium chelating agent (ethylene diamine tetra acetic acid,
EDTA). The separation force was, however, significantly decreased on treating cells with the actin disrupting agent Cytochalasin-D.
These results show that the dual micropipette assay is a simple and useful experimental technique for quantifying cell–cell
adhesion. 相似文献
929.
Joseph Park Jaemoon Yang Jaemin Lee Eun-Kyung Lim Jin-Suck Suh Yong-Min Huh Seungjoo Haam 《Journal of colloid and interface science》2009,340(2):57
Novel bifunctional fluorescent magneto polymeric nanoprobes (FMPNs) were synthesized to provide simultaneous diagnostic information via magnetic resonance imaging (MRI) and optical imaging. FMPNs consist of ultra-sensitive magnetic nanocrystals that function as MR probes combined with Nile Red, which functions as a fluorescent probe. FMPNs were encapsulated by a nano-emulsion method in polyvinyl alcohol (PVA, 87–89% hydrolyzed) through a matrix of polymethyl methacrylate (PMMA). FMPNs exhibited excellent colloidal stability and monodispersity. The production of MR and optical images demonstrated that FMPNs have potential as dual-mode imaging agents. 相似文献
930.
Yasuhide Numata 《Journal of Algebraic Combinatorics》2007,26(1):27-45
Young's lattice, the lattice of all Young diagrams, has the Robinson-Schensted-Knuth correspondence, the correspondence between
certain matrices and pairs of semi-standard Young tableaux with the same shape. Fomin introduced generalized Schur operators
to generalize the Robinson-Schensted-Knuth correspondence. In this sense, generalized Schur operators are generalizations
of semi-standard Young tableaux. We define a generalization of Schur polynomials as expansion coefficients of generalized
Schur operators. We show that the commutation relation of generalized Schur operators implies Pieri's formula for generalized
Schur polynomials. 相似文献