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Notes: Abstract Directional and orientational components usually coexist and are mixed in the cell's overall responses when moving optical stimuli are used to study the response characteristics of visual neurons. While these two properties were quantified with all the previous methods for data analysis, their effects could not be efficiently separated from each other, and thus the analyses were imperfect. In this paper, theoretical evidence and examples are provided to show the defects of the old methods. In order to separate the two components completely, we propose to apply optimal regression analysis with the sine-cosine function series as the fundamental variables. Based on this separation, we defined the orientational selectivity as variation of response strength with orientation and performed integration and averaging to quantify the two properties [cf. Eqs. (5) and (6)]. The present method has the advantages of completeness and accuracy, and can detect some details which would have been missed by other methods. An explanation of the intrinsic implications of the method and our comprehension of directional and orientational selectivities and preferred direction and orientation are also given.

Notes: Abstract. Directional and orientational components usually coexist and are mixed in the cell's overall responses when moving optical stimuli are used to study the response characteristics of visual neurons. While these two properties were quantified with all the previous methods for data analysis, their effects could not be efficiently separated from each other, and thus the analyses were imperfect. In this paper, theoretical evidence and examples are provided to show the defects of the old methods. In order to separate the two components completely, we propose to apply optimal regression analysis with the sine-cosine function series as the fundamental variables. Based on this separation, we defined the orientational selectivity as variation of response strength with orientation and performed integration and averaging to quantify the two properties [cf. Eqs. (5) and (6)]. The present method has the advantages of completeness and accuracy, and can detect some details which would have been missed by other methods. An explanation of the intrinsic implications of the method and our comprehension of directional and orientational selectivities and preferred direction and orientation are also given.

Notes: Abstract  The robust behavior, the degree of response linearity, and the aspect of contrast gain control in visual cortical simple cells are (amongst others) the result of the interplay between excitatory and inhibitory afferent and intracortical connections. The goal of this study was to suggest a simple intracortical connection pattern, which could also play a role in other cortical substructures, in order to generically obtain these desired effects within large physiological parameter ranges. To this end we explored the degree of linearity of spatial summation in visual simple cells experimentally and in different models based on half-wave rectifying cells (’’push-pull models’’). Visual cortical push-pull connection schemes originated from antagonistic motor-control models. Thus, this model class is widely applicable but normally requires a rather specific design. On the other hand we showed that a more generic version of a push-pull model, the so-called cascaded inhibitory intracortical connection scheme, which we implemented in a biologically realistic simulation, naturally explains much of the experimental data. We investigated the influence of the afferent and intracortical connection structure on the measured linearity of spatial summation in simple cells. The analysis made use of the relative modulation measure, which is easy to apply but is limited to moving sinusoidal grating stimuli. We introduced two basic push-pull models, where the order of threshold nonlinearity and linear summation is reversed. Very little difference is observed with the relative modulation measure for these models. Alterative models, like half-wave squaring models, were also briefly discussed. Of all model parameters, the ratio of excitation to inhibition in the simple cell exerts the most crucial influence on the relative modulation. Linearity deteriorates as soon as excitatory and inhibitory inputs are imbalanced and the relative modulation drops. This prediction was tested experimentally by extracellular recordings from cat area 17 simple cells and we found that about 62% showed a significant deviation from linear behavior. The problem that individual basic push-pull models are hard to distinguish experimentally led us to suggest a different solution. In order to generically account for the observed behavior (e.g., imbalance of excitation versus inhibition), we suggested a rather generic version of a push-pull model where it no longer mattered about (the hard-to-distinguish) fine differences in connectivity. Thus, we introduced a new class of biophysically realistic models (’’cascaded inhibition’’). This model class requires very little connection specificity and is therefore highly robust against parameter variations. Up to 25 cells are connected to each target cell. Thereby a highly interconnected network is generated, which also leads to disinhibition at some parts of an individual receptive field. We showed that the performance of these models simulates the degree of linearity and its variability in recal simple cells with comparatively high accuracy. This behavior can be explained by the self-regulating properties of a cascaded inhibitory connection scheme by which the balance between excitation and inhibition at a given cell is improved by the joint network effects. The virtues and the generic design of this connection pattern, therefore, allow to speculate that it is used also in other parts of the cortex.

Notes: In recent years, chitosan/inorganic composites have attracted increasing attention due toits fascinating properties and potential applications in biodegradable materials, drug release,electrochemical sensor, packaging materials and so on. Chitosan/inorganic composites are expectedto be as an effective way to overcome shortcomings of slow flocculating speed of chitosan particles,not good enough to meet those wide range of applications in wasterwater treatment. In this study,novel chitosan/clay/PAC (polyaluminium chloride) composite was prepared, and it was used intreating effluent from dying and finishing process. One set of orthogonal experiments wereconducted to optimize the experimental condition, and the results showed that removal of waste dyeis affected by the dosage of chitosan, PAC, clay, pH and treatment time. The experiments resultsindicated that the effluent from dying and finishing process treated by the prepared compositesbecame obviously fade, and its COD (chemical oxygen demand) decreased from original1398.2mg/L to 197.6mg/L, the removing rate reached 85.9%

Notes: Rapid reverse technology is one of the key technologies with which the enterprisesdevelop new product and occupy the market rapidly. How to realize the reverse measurement andCAD geometry reconstruction rapidly and accurately is always the most important focus for theresearchers. Based on the laser scanning technology, the realization principle of the laser linescanning measuring system is presented and the approaches to improve the precision are alsoanalysed in the paper. The self-adaptation adjustment of the probe position can move the light knifeimage to the optimal imaging area of the CCD according to the calibration result, which will ensurethe measurement precision of the CCD image. With the inner velocity loop and outer position loopfeedback control, the simple axis position precision of the mechanical system can be controlledwithin 5um. In order to pick up the points of the light knife centre rationally and exactly, thereconstruction-disperse iteration algorithm is put forward. After processed by different iterationtimes, the optimal points can be obtained. The reconstruction method of curve and surface based onNURBS is also given. The paper presents the application and realization of the system at last, whichrealizes the curve and surface measurement with high precision

Notes: It was shown that chitosan and hydroxy-aluminum pillared montmorillonites wereexcellent materials for the removal of dyes and metal ions from effluent of dying and finishing.Chitosan/ hydroxy-aluminum pillared montmorillonite nanocomposites are expected to play amultiplex role in the treating process. In this study, the nanocomposite was prepared by incorporatinghydroxy-aluminum pillared montmorillonite into chitosan solution that diluted acetic acid was usedas solvent for dissolving the chitosan. The ratio of chitosan to the cationic exchange capacity of themontmorillonite was about 1:1, 2:1, 3:1, 4:1 and 6:1, respectively. The nanocomposites werecharacterized by XRD (X-ray diffraction), SEM (Scanning Electron Microscopy). The experimentalresults indicated that the presence of hydroxy-aluminum cation was in favor of the chitosanintercalation and the interlayers of MMT was intercalated with the bilayers of chitosan sheets. andthey can be used in absorption of organic and metal ions for dying and finishing effluent

Notes: The explicit numerical method is used to trace the impact procedure of the tube columnsimpacted by a rigid body. The bar and rectangle tube models are both used to simulate the tubecolumn. The elastic and elas-plastic impact load with different mass ratio and impact speed areobtained. The calculation results show that: for elastic models, the bigger the mass ratio and thehigher the rigid body speed, the bigger the peak value of elastic impact load; at the same time, themore obvious the reduction effect of local buckling of rectangle tube on the peak value of impact loadand the longer the contact time of tube model; so the peak value of impact load of the rectangle tube isnot proportional to the rigid body speed. The stress wave in the tube causes a little difference betweenthe load curves of tube model and bar model. For elas-plastic models, the higher the rigid body speedand the smaller the mass ratio, the bigger the peak value of impact load and the longer the contacttime. The higher the rigid body speed, the bigger the difference between elastic and elas-plasticimpact load peak value due to the expanding of plasticity. Because of the effect of local buckling, thepeak value of elas-plastic impact load of rectangle tube is always lower than that of bar

Notes: Biomechanical models of implanting prostheses into femora by means of press fit, i.e. themechanics of non-homogeneous layer-like composites, have been used to quantify the press-fit strengthand circumferential stress of the interface, when femora are partially replaced by different thicknesses ofbioactive ceramic coatings on a prosthesis surface during the initial implant stage. The maximum press-fitstrength appears on the interface between femora and Ti alloy prostheses with non-coating; the press-fitstrength decreases with the increased thickness of the coating. The circumferential stress displayed as thelarge tensile stress at the femoral side of the interface; the compressive stress, appeared at the side of thecoating and Ti alloy prosthesis. The shearing strength, jointing between the prostheses and femora wouldbe bigger with the thinner bioactive ceramic coatings. Considering the biodegradability of bioactiveceramic coatings, e.g. hydroxyapatite, HA, it is concluded that the optimum thickness of the bioactiveceramic coatings will be about 50-60 microns