Design of a freeform, luminance spreading illumination lens with a continuous surface

2018 ◽  
Author(s):  
Karel Desnijder ◽  
Ward Deketelaere ◽  
Michael Vervaeke ◽  
Hugo Thienpont ◽  
Peter Hanselaer ◽  
...  
Keyword(s):  
Continuous Surface

Antithrombin III Binding to Surface Immobilized Heparin and Its Relation to F Xa Inhibition

1987 ◽  
Vol 58 (04) ◽  
pp. 1064-1067 ◽  
Author(s):  
K Kodama ◽  
B Pasche ◽  
P Olsson ◽  
J Swedenborg ◽  
L Adolfsson ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Ionic Strength ◽  
Surface Coating ◽  
Antithrombin Iii ◽  
Lower Class ◽  
Biologically Active ◽  
High Affinity ◽  
Heparin Coating ◽  
Continuous Surface ◽  
Approximate Molecular Weight

SummaryThe mode of F Xa inhibition was investigated on a thromboresistant surface with end-point attached partially depoly-merized heparin of an approximate molecular weight of 8000. Affinity chromatography revealed that one fourth of the heparin used in surface coating had high affinity for antithrombin III (AT). The heparin surface adsorbed AT from both human plasma and solutions of purified AT. By increasing the ionic strength in the AT solution the existence of high and low affinity sites could be shown. The uptake of AT was measured and the density of available high and low affinity sites was found to be in the range of 5 HTid 11 pic.omoles/cmf, respectively Thus the estimated density of biologically active high and low ailmity heparm respectively would be 40 and 90 ng/cm2 The heparin coating did not take up or exert F Xa inhibition by itself. With AT adsorbed on both high and low affinity heparin the surface had the capacity to inhibit several consecutive aliquots of F Xa exposed to the surface. When mainly high affinity sites were saturated with AT the inhibition capacity was considerably lower. Tt was demonstrated that the density of AT on both high and low affinity heparin determines the F Xa inhibition capacity whereas the amount of AT on high affinity sites limits the rate of the reaction. This implies that during the inhibition of F Xa there is a continuous surface-diffusion of AT from sites of a lower class to the high affinity sites where the F Xa/AT complex is formed and leaves the surface. The ability of the immobilized heparin to catalyze inhibition of F Xa is likely to be an important component for the thromboresistant properties of a heparin coating with non-compromized AT binding sequences.

A Local Approach for Computing Smooth B-spline Surfaces for Arbitrary Quadrilateral Base Meshes

2021 ◽  
pp. 1-28
Author(s):  
Dennis Mosbach ◽  
Katja Schladitz ◽  
Bernd Hamann ◽  
Hans Hagen
Keyword(s):  
Degrees Of Freedom ◽  
Tangent Plane ◽  
Local Approach ◽  
Approximation Process ◽  
Surface Approximation ◽  
B Spline ◽  
Spline Surfaces ◽  
Continuous Surface ◽  
Normal Vectors ◽  
The Individual

Abstract We present a method for approximating surface data of arbitrary topology by a model of smoothly connected B-spline surfaces. Most of the existing solutions for this problem use constructions with limited degrees of freedom or they address smoothness between surfaces in a post-processing step, often leading to undesirable surface behavior in proximity of the boundaries. Our contribution is the design of a local method for the approximation process. We compute a smooth B-spline surface approximation without imposing restrictions on the topology of a quadrilateral base mesh defining the individual B-spline surfaces, the used B-spline knot vectors, or the number of B-spline control points. Exact tangent plane continuity can generally not be achieved for a set of B-spline surfaces for an arbitrary underlying quadrilateral base mesh. Our method generates a set of B-spline surfaces that lead to a nearly tangent plane continuous surface approximation and is watertight, i.e., continuous. The presented examples demonstrate that we can generate B-spline approximations with differences of normal vectors along shared boundary curves of less than one degree. Our approach can also be adapted to locally utilize other approximation methods leading to higher orders of continuity.

scholarly journals Rapid Fabrication of Continuous Surface Fresnel Microlens Array by Femtosecond Laser Focal Field Engineering

Micromachines ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 112 ◽  
Author(s):  
Linyu Yan ◽  
Dong Yang ◽  
Qihuang Gong ◽  
Yan Li
Keyword(s):  
Femtosecond Laser ◽  
Three Dimensional ◽  
Fresnel Lens ◽  
Two Dimensional ◽  
Direct Writing ◽  
Lens Array ◽  
Two Photon ◽  
Rapid Fabrication ◽  
Continuous Surface ◽  
Two Photon Polymerization

Femtosecond laser direct writing through two-photon polymerization has been widely used in precision fabrication of three-dimensional microstructures but is usually time consuming. In this article, we report the rapid fabrication of continuous surface Fresnel lens array through femtosecond laser three-dimensional focal field engineering. Each Fresnel lens is formed by continuous two-photon polymerization of the two-dimensional slices of the whole structure with one-dimensional scan of the corresponding two-dimensional engineered intensity distribution. Moreover, we anneal the lens array to improve its focusing and imaging performance.

scholarly journals Transport analysis of ozone enhancement in Southern Ontario during BAQS-Met

2011 ◽  
Vol 11 (6) ◽  
pp. 2569-2583 ◽  
Author(s):  
H. He ◽  
D. W. Tarasick ◽  
W. K. Hocking ◽  
T. K. Carey-Smith ◽  
Y. Rochon ◽  
...  
Keyword(s):  
Air Quality ◽  
Numerical Models ◽  
Stratospheric Ozone ◽  
Weather Prediction ◽  
Surface Ozone ◽  
Air Quality Model ◽  
Quality Model ◽  
Stratospheric Intrusion ◽  
Continuous Surface ◽  
Consistent Picture

Abstract. Twice-daily ozonesondes were launched from Harrow, in southwestern Ontario, Canada, during the BAQS-Met (Border Air Quality and Meteorology Study) field campaign in June and July of 2007. A co-located radar windprofiler measured tropopause height continuously. These data, in combination with continuous surface ozone measurements and geo-statistical interpolation of satellite ozone observations, present a consistent picture and indicate that a number of significant ozone enhancements in the troposphere were observed that were the result of stratospheric intrusion events. The combined observations have also been compared with results from two Environment Canada numerical models, the operational weather prediction model GEM (as input to FLEXPART), and a new version of the regional air quality model AURAMS, in order to examine the ability of these models to accurately represent sporadic cross-tropopause ozone transport events. The models appear to reproduce intrusion events with some skill, implying that GEM dynamics (which also drive AURAMS) are able to represent such events well. There are important differences in the quantitative comparison, however; in particular, the poor vertical resolution of AURAMS around the tropopause causes it to bring down too much ozone in individual intrusions. These campaign results imply that stratospheric intrusions are important to the ozone budget of the mid-latitude troposphere, and appear to be responsible for much of the variability of ozone in the free troposphere. GEM-FLEXPART calculations indicate that stratospheric ozone intrusions contributed significantly to surface ozone on several occasions during the BAQS-Met campaign, and made a moderate but significant contribution to the overall tropospheric ozone budget.

scholarly journals From felt tip to technology: the challenges of representing traditional knowledge in a GIS platform to create a knowledge surface

2021 ◽  
Author(s):  
Julie B. Robertson
Keyword(s):  
Knowledge Representation ◽  
Traditional Knowledge ◽  
Indigenous Peoples ◽  
The Arctic ◽  
Vector Data ◽  
Collective Knowledge ◽  
Vector Maps ◽  
Spatial Dimensions ◽  
Continuous Surface ◽  
Forms Of Knowledge

Traditional knowledge (TK) has been the keystone to survival in the Arctic for thousands of years. Caribou are integral to the society, health and culture of the Inuit, the Indigenous peoples of the Arctic. There is a lack of research regarding caribou on King William Island (KWI), Nunavut. Through a project in Gjoa Haven, located on KWI, Inuit Elders and hunters used maps to help represent their knowledge of caribou in the region. These 32 maps were processed in a GIS to explore the spatial dimensions of TK, and different forms of knowledge representation. Using vector data the features drawn were separated into lines and polygons to show hotspots of caribou knowledge. Using a fuzzy raster methodology, all caribou data was summed to create a collective knowledge surface of the caribou features. These maps refine the data from the vector maps and create a continuous surface that aims to better reflect the collective nature of TK. This research explores the challenges of representing TK using western technologies, and application of fuzzy methodologies for improving the representation.

scholarly journals Optical method for measuring bed topography and flow depth in an experimental flume

Solid Earth ◽  
2011 ◽  
Vol 2 (2) ◽  
pp. 143-154 ◽  
Author(s):  
A. Limare ◽  
M. Tal ◽  
M. D. Reitz ◽  
E. Lajeunesse ◽  
F. Métivier
Keyword(s):  
Optical Method ◽  
Full Range ◽  
Reference Plane ◽  
Flow Depth ◽  
Bed Topography ◽  
Braided Channel ◽  
Continuous Surface ◽  
Commercial Software Package ◽  
Moire Method ◽  
Very High

Abstract. We describe an optical method known as moiré for acquiring quasi-simultaneous measurements of bed topography and flow depth in laboratory experiments. The moiré method is based on projecting a fringe pattern (grating) on the bed and analyzing the deformation of the pattern caused by the topography with respect to a reference plane. The height of the object is encoded in the phase of the pattern and can be retrieved either through Fourier transform or phase shifting algorithms. The methodology enables image-based non-contact measurements over a continuous surface at very high spatial and temporal resolutions. We use a commercial software package of a moiré method called Light3D to map bed topography and flow depth in an experimental braided channel and demonstrate how the method can be used to characterize a full range of statistics not previously possible.

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