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61.
62.
纳米尺寸硫化镍化学增感剂 总被引:4,自引:3,他引:4
本文发现了硫化镍纳米粒子对卤化银乳剂的化学增感作用,采用水不溶性的硫化镍纳米粒子作为化学增感剂,与水溶性的硫代硫酸钠增感剂相比,可以在乳剂灰雾增加不大的条件下明显提高乳剂的感光度和反差。 相似文献
63.
Solvent assisted spreading of CoO over monolayer MoO3/Al2O3 catalysts has been studied. CoCO3 · Co(OH)2 and CoCO3 reacted with MoO3/Al2O3 in water slurries. CoO deposition over MoO3/Al2O3 extrudates was followed by EPMA. In the set of eleven MoO3/Al2O3 catalysts, the amount of CoO adsorbed was roughly proportional to the surface area of MoO3 monolayer. The adsorbed Co species efficiently enhanced the HDS activity. 相似文献
64.
Halil Akçakaya 《Advanced Robotics》2014,28(9):601-611
Set point tracking control of autonomous underwater vehicle (AUV) via robust model predictive control (RMPC) is considered. Input-constrained RMPC with integral action, which has been developed in our previous work, is used to control the AUV in this study. In order to derive a RMPC control rule, non-linear dynamics of AUV with six degree of freedom is linearized at certain operating points. So, horizontal and vertical plane dynamics of system are represented by linear models which have polytopic uncertainties. Since the derived control rule will be used in real time, the computation time should be reduced. To overcome this computational time problem and get rid of trial–error step of Algorithm 1, a new algorithm is proposed here. The simulations are carried out using the control rule based on this algorithm and these results are presented. 相似文献
65.
This paper is the first one of the two papers entitled “modeling and solving mixed-model assembly line balancing problem with setups”, which has the aim of developing the mathematical programming formulation of the problem and solving it with a hybrid meta-heuristic approach. In this current part, a mixed-integer linear mathematical programming (MILP) model for mixed-model assembly line balancing problem with setups is developed. The proposed MILP model considers some particular features of the real world problems such as parallel workstations, zoning constraints, and sequence dependent setup times between tasks, which is an actual framework in assembly line balancing problems. The main endeavor of Part-I is to formulate the sequence dependent setup times between tasks in type-I mixed-model assembly line balancing problem. The proposed model considers the setups between the tasks of the same model and the setups because of the model switches in any workstation. The capability of our MILP is tested through a set of computational experiments. Part-II tackles the problem with a multiple colony hybrid bees algorithm. A set of computational experiments is also carried out for the proposed approach in Part-II. 相似文献
66.
Martin Saska Tomáš Krajník Vojtěch Vonásek Zdeněk Kasl Vojtěch Spurný Libor Přeučil 《Journal of Intelligent and Robotic Systems》2014,73(1-4):603-622
A fault-tolerant method for stabilization and navigation of 3D heterogeneous formations is proposed in this paper. The presented Model Predictive Control (MPC) based approach enables to deploy compact formations of closely cooperating autonomous aerial and ground robots in surveillance scenarios without the necessity of a precise external localization. Instead, the proposed method relies on a top-view visual relative localization provided by the micro aerial vehicles flying above the ground robots and on a simple yet stable visual based navigation using images from an onboard monocular camera. The MPC based schema together with a fault detection and recovery mechanism provide a robust solution applicable in complex environments with static and dynamic obstacles. The core of the proposed leader-follower based formation driving method consists in a representation of the entire 3D formation as a convex hull projected along a desired path that has to be followed by the group. Such an approach provides non-collision solution and respects requirements of the direct visibility between the team members. The uninterrupted visibility is crucial for the employed top-view localization and therefore for the stabilization of the group. The proposed formation driving method and the fault recovery mechanisms are verified by simulations and hardware experiments presented in the paper. 相似文献
67.
Stéphane Roux Hugo Leclerc François Hild 《Journal of Mathematical Imaging and Vision》2014,49(2):335-351
Tomographic reconstruction of a binary image from few projections is considered. A novel heuristic algorithm is proposed, the central element of which is a nonlinear transformation ψ(p)=log(p/(1?p)) of the probability p that a pixel of the sought image be 1-valued. It consists of backprojections based on ψ(p) and iterative corrections. Application of this algorithm to a series of artificial test cases leads to exact binary reconstructions, (i.e., recovery of the binary image for each single pixel) from the knowledge of projection data over a few directions. Images up to 106 pixels are reconstructed in a few seconds. A series of test cases is performed for comparison with previous methods, showing a better efficiency and reduced computation times. 相似文献
68.
François Chapeau-Blondeau Christian Jeanguillaume 《Journal of Mathematical Imaging and Vision》2014,49(2):467-480
For photon emission tomography, the maximum likelihood (ML) estimator for image reconstruction is generally solution to a nonlinear equation involving the vector of measured data. No explicit closed-form solution is known in general for such a nonlinear ML equation, and numerical resolution is usually implemented, with a very popular iterative method formed by the expectation-maximization algorithm. The numerical character of such resolutions usually makes it difficult to obtain a general characterization of the performance of the ML solution. We show that the nonlinear ML equation can be replaced by an equivalent system of two dual linear equations nonlinearly coupled. This formulation allows us to exhibit explicit (to some extent) forms for the solutions to the ML equation, in general conditions corresponding to the various possible configurations of the imaging system, and to characterize their performance with expressions for the mean-squared error, bias and Cramér-Rao bound. The approach especially applies to characterize the ML solutions obtained numerically, and offers a theoretical framework to contribute to better appreciation of the capabilities of ML reconstruction in photon emission tomography. 相似文献
69.
70.
Jan Pospíil 《大分子材料与工程》1988,158(1):221-231
Inherent chemical activity, physical persistence and good compatibility are factors determining the efficiency of a stabilizer observed during the degradation of amorphous and crystalline synthetic polymers. Synthesis of macromolecular stabilizers is one of the ways used to solve the problem of physical persistency of stabilizers under severe aggressive environmental attacks on polymers. General types of macromolecular stabilizers, routes to their synthesis and characteristic examples of macromolecular antioxidants, UV absorbers, hindered amine light stabilizers, flame retarders and biostabilizers, as well as of polyfunctional systems are given. Problems connected with the use of macromolecular stabilizers are mentioned. 相似文献