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141.
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The Laplace–Beltrami mesh enhancement algorithm of Hansen et al. , and has been implemented and broadened to include meshes containing dendritic elements and allowing for boundary node movement. This implementation operates on an unstructured two-dimensional mesh by forming an equivalent weak statement using finite element interpolation, assembly, and solution ideas to iteratively place those nodes allowed to move. Moving boundary nodes are constrained to follow the boundary geometry described as a Wilson–Fowler spline (e.g., [3, Section 2.1.3.1]). Implementation details concerning the element basis set modifications, the metric tensor for dendritic element treatment and boundary node movement are presented. Laplacian (e.g., [6]) enhancement is included as a special case. Results are presented which illustrate the algorithm for three test problems. 相似文献
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In order to guide the needle to the correct location in 3D US-guided brachytherapy, the needle is continuously tracked as it is being inserted. A pre-scan before the needle insertion and a post-scan after the needle insertion are subtracted to obtain a difference image containing the needle. The image is projected along two orthogonal directions approximately perpendicular to the needle, and the 3D needle is reconstructed from the segmented needles in the two projected images. The seeds implanted with the needle are located in the cropped volume along the needle. Thus, the seeds are segmented using a tri-bar model and 3D line segment patterns. Finally, the positions of the seeds are determined using a peak detection technique. Experiments with agar and turkey/chicken phantoms as well as patient data demonstrated that our needle segmentation technique could segment the needle in near real-time with an accuracy of 0.6 mm in position and 1.0 degrees in orientation. The true-positive rate for seed segmentation is 100% for the agar phantom and 93% for the chicken phantom. The average distance to manual seed segmentation was 1.0mm for the agar phantom and 1.7 mm for the chicken phantom. 相似文献
145.
N. D. Lowhorn W. Wong-Ng W. Zhang Z. Q. Lu M. Otani E. Thomas M. Green T. N. Tran N. Dilley S. Ghamaty N. Elsner T. Hogan A. D. Downey Q. Jie Q. Li H. Obara J. Sharp C. Caylor R. Venkatasubramanian R. Willigan J. Yang J. Martin G. Nolas B. Edwards T. Tritt 《Applied Physics A: Materials Science & Processing》2009,94(2):231-234
A Standard Reference Material (SRM™) for the Seebeck coefficient is critical for inter-laboratory data comparison and for instrument calibration. To develop
this SRM™, we have conducted an international round-robin measurement survey of two candidate materials—undoped Bi2Te3 and constantan (55% Cu and 45% Ni alloy). Measurements were performed in two rounds by twelve laboratories involved in active
thermoelectric research using a number of commercial and custom-built measurement systems and techniques. We report the results
of these measurements and the statistical analysis performed. Based on this extensive study, we have selected Bi2Te3 as the prototype standard material. 相似文献
146.
A fast handheld two-photon fiber-optic fluorescence endoscope for three-dimensional (3D) in vivo cellular imaging is developed. The compact handheld probe of the two-photon endoscope can simply be placed into contact with the target tissue to reveal clear 3D surface and subsurface histological images without biopsy. The new system has, to the best of our knowledge, the largest field of view (FOV) of 475 microm x 475 microm and a 3D imaging volume larger than 475 microm x 475 microm x 250 microm. A real-time two-photon fluorescence image is displayed at 0.4 mm(2)/s. The lateral and axial resolutions of the two-photon fluorescence endoscope are better than 1 and 14.5 microm, respectively. 相似文献
147.
We quantify correlations (quantum and/or classical) between two continuous-variable modes as the maximal number of correlated bits extracted via local quadrature measurements. On Gaussian states, such "bit quadrature correlations" majorize entanglement, reducing to an entanglement monotone for pure states. For non-Gaussian states, such as photonic Bell states, photon-subtracted states, and mixtures of Gaussian states, the bit correlations are shown to be a monotonic function of the negativity. This quantification yields a feasible, operational way to measure non-Gaussian entanglement in current experiments by means of direct homodyne detection, without a complete state tomography. 相似文献
148.
Martin J. Farncombe Keith R. Jennings Rod S. Mason Urs P. Schlunegger 《Journal of mass spectrometry : JMS》1983,18(12):612-616
The amino acid sequence of three simple peptides has been determined by the technique of metastable mapping. The products of decompositions in the first field free region of a forward geometry double focussing mass spectrometer are studied by decreasing the electric sector field between scans of the magnetic field. 相似文献
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