Modification of the surfaces of polycarbonate (PC) with the use of a solution of tin (II) chloride renders them hydrophilic. The surface draping is stable against exposure to water and to alcohols. Exposure to alkanes reduces but does not diminish the effect. The method is compatible—in using the same solvent and temperature—with the hydrophobic modification of PC Jankowski et al. ( Lab Chip 11:748–752, 2011). The combination of these methods makes it possible to generate single and multiple monodisperse emulsions with the use of flow-focusing junctions in systems made in PC—material that is suitable for fabrication of multilayer, high throughput microfluidic devices. 相似文献
In this paper we present new control algorithms for robots with dynamics described in terms of quasi-velocities (Kozłowski,
Identification of articulated body inertias and decoupled control of robots in terms of quasi-coordinates. In: Proc. of the
1996 IEEE International Conference on Robotics and Automation, pp. 317–322. IEEE, Piscataway, 1996a; Zeitschrift für Angewandte Mathematik und Mechanik 76(S3):479–480, 1996c; Robot control algorithms in terms of quasi-coordinates. In: Proc. of the 34 Conference on Decision and Control, pp. 3020–3025,
Kobe, 11–13 December 1996, 1996d). The equations of motion are written using spatial quantities such as spatial velocities, accelerations, forces, and articulated
body inertia matrices (Kozłowski, Standard and diagonalized Lagrangian dynamics: a comparison. In: Proc. of the 1995 IEEE
Int. Conf. on Robotics and Automation, pp. 2823–2828. IEEE, Piscataway, 1995b; Rodriguez and Kreutz, Recursive Mass Matrix Factorization and Inversion, An Operator Approach to Open- and Closed-Chain
Multibody Dynamics, pp. 88–11. JPL, Dartmouth, 1998). The forward dynamics algorithms incorporate new control laws in terms of normalized quasi-velocities. Two cases are considered:
end point trajectory tracking and trajectory tracking algorithm, in general. It is shown that by properly choosing the Lyapunov
function candidate a dynamic system with appropriate feedback can be made asymptotically stable and follows the desired trajectory
in the task space. All of the control laws have a new architecture in the sense that they are derived, in the so-called quasi-velocity
and quasi-force space, and at any instant of time generalized positions and forces can be recovered from order recursions, where denotes the number of degrees of freedom of the manipulator. This paper also contains the proposition of a sliding mode control,
originally introduced by Slotine and Li (Int J Rob Res 6(3):49–59, 1987), which has been extended to the sliding mode control in the quasi-velocity and quasi-force space. Experimental results illustrate
behavior of the new control schemes and show the potential of the approach in the quasi-velocity and quasi-force space.
Authors are with Chair of Control and Systems Engineering. 相似文献
Samples of -Fe (Armco) have been deformed by 50% in compression. These have then been annealed at 400 °C, considerably below the conventional recrystallization temperature, and the evolution of grain size and shape quantified. Initially the grain size is found to decrease whilst, at the same time, the grain-shape anisotropy also decreases. It is suggested that a continuous recrystallization process which favours the generation of higher angle grain boundaries is the underlying mechanism. Annealing for longer times gives rise to an increase in grain size with the development of undulations on the grain surfaces. The mechanism suggested for this behaviour involves the annihilation of segments of sub-boundaries on to a pre-existing boundary from either side of the boundary. 相似文献
Using the wide-angle X-ray scattering method, the degree of crystallinity of suspension copolymers and terpolymers of acrylonitrile (AN) and divinylbenzene (DVB) were determined. Copolymers with various degrees of cross-linking (5%–50% DVB) were prepared in the presence of thermodynamically different solvents added in order to obtain porous structure. It was found that copolymers with a degree of cross-linking of 0.1% DVB have a crystallinity index below 0.2, although the crystallinity index of PAN obtained under the same conditions is 0.5. Owing to the solvation conditions, even in copolymers with a degree of cross-linking of 20% DVB, ordered regions occur, and dilution of the polymerization mixture with poor solvents cause a decrease in the degree of crystallinity of these copolymers. Terpolymers AN, butyl acrylate (BA) or vinyl acetate (VA) have less ordered structure for the same amount of DVB. Methacrylonitrile and DVB copolymers obtained under the same conditions as AN and DVB are amorphous. 相似文献
In this paper it has been shown that, with the advent of lasers with a very short pulse duration, the effect of thermal wave propagation becomes important. To consider this effect, hyperbolic heat conduction in thin gold films was studied. It was shown that for heat fluxes of the order 108 W·cm–2, a thermal wave is generated in thin gold films. The consideration of the hyperbolicity of heat transfer enables one to describe the temperature profile with one value of fluence. 相似文献
Versatile optimization of the synthesis method and composition of Yb3+ and Tm3+ co-doped CaF2 nanoparticles as well as a novel biofunctionalization method were developed and evaluated.Through multistep synthesis,the luminescence intensity of the Tm3+ activator was enhanced by more than 10-fold compared to standard one-step synthesis.The proposed methods were used to homogenously distribute the doping ions within the nanoparticle's volume and thus reduce luminescence quenching.Optimization of dopant ions concentration led to the selection of the most efficient visible and near-infrared up-converting nanoparticles,which were CaF2 doped with 10% Yb3+ 0.05% Tm3+ and 20% Yb3+ 0.5% Tm3+,respectively.To illustrate the suitability of the synthesized nanoparticles as bio-labels,a dedicated biofunctionalization method was used,and the nanoparticles were applied for labeling and imaging of Candida albicans cells.This method shows great promise because of extremely low background and high specificity because of the presence of the attached molecules. 相似文献
Context: Continuous processing is an innovative production concept well known and successfully used in other industries for many years. The modern pharmaceutical industry is facing the challenge of transition from a traditional manufacturing approach based on batch-wise production to a continuous manufacturing model.
Objective: The aim of this article is to present technological progress in manufacturing based on continuous and semi-continuous processing of the solid oral dosage forms.
Methods: Single unit processes possessing an alternative processing pathway to batch-wise technology or, with some modification, an altered approach that may run continuously, and are thus able to seamlessly switch to continuous manufacturing are briefly presented. Furthermore, the concept of semi-continuous processing is discussed. Subsequently, more sophisticated production systems created by coupling single unit processes and comprising all the steps of production, from powder to final dosage form, were reviewed. Finally, attempts of end-to-end production approach, meaning the linking of continuous synthesis of API from intermediates with the production of final dosage form, are described.
Results: There are a growing number of scientific articles showing an increasing interest in changing the approach to the production of pharmaceuticals in recent years. Numerous scientific publications are a source of information on the progress of knowledge and achievements of continuous processing. These works often deal with issues of how to modify or replace the unit processes in order to enable seamlessly switching them into continuous processing. A growing number of research papers concentrate on integrated continuous manufacturing lines in which the production concept of “from powder to tablet” is realized. Four main domains are under investigation: influence of process parameters on intermediates or final dosage forms properties, implementation of process analytical tools, control-managing system responsible for keeping continuous materials flow through the whole manufacturing process and the development of new computational methods to assess or simulate these new manufacturing techniques. The attempt to connect the primary and secondary production steps proves that development of continuously operating lines is possible.
Conclusion: A mind-set change is needed to be able to face, and fully assess, the advantages and disadvantages of switching from batch to continuous mode production. 相似文献
The specific heat C(T) of the monoclinic RbDy(WO4)2crystal has been studied at very low temperatures 0.2T1.9 K and in magnetic fields 0H0.38 T. The Neel temperature was shown to be equal to TN = 0.818 ± 0.005 K. The experimental value of the effective exchange parameter was obtained to be equal to J/k = – 0.798 K. The C T) dependence below Neel temperature 0.5TN0.99TN) is well described by 2D Ising model, whereas in the temperature region close above TN(1.01 TN2TN) it can be described by neither 2D, nor 3D Ising model. The experimental and theoretical H-TNdiagrams for fieldHaare in a reasonable agreement for simple quadratic lattice.相似文献