We introduce a new algebraic approach dealing with the problem of computing the topology of an arrangement of a finite set of real algebraic plane curves presented implicitly. The main achievement of the presented met...We introduce a new algebraic approach dealing with the problem of computing the topology of an arrangement of a finite set of real algebraic plane curves presented implicitly. The main achievement of the presented method is a complete avoidance of irrational numbers that appear when using the sweeping method in the classical way for solving the problem at hand. Therefore, it is worth mentioning that the efficiency of the proposed method is only assured for low-degree curves.展开更多
Hastening transmission by efficiently providing compression is our goal in this work. Image compression consists in reducing information size representing an image. Elimination of redundancies and non-pertinent inform...Hastening transmission by efficiently providing compression is our goal in this work. Image compression consists in reducing information size representing an image. Elimination of redundancies and non-pertinent information enables memory space minimization and thus fast data transmission. Optics can offer an alternative choice to overcome the limitation of numerical compression algorithms. In this paper, we propose real-time optical image compression using a real Fourier plane to save time required for compression by using the principles of coherent optics. Digital and optical simulation results are presented and analyzed. An optical compression decompression setup is demonstrated using two different SLMs (SEIKO and DisplayTech). The purpose of this method is to simplify our earlier method, improve the quality of reconstructed image, and avoid the disadvantages of numerical algorithms.展开更多
We prove the non-existence of Hopf real hypersurfaces in complex two-plane Grassmannians whose Jacobi operators or the Jacobi corresponding to the directions in the distribution are of Codazzi type if they satisfy a f...We prove the non-existence of Hopf real hypersurfaces in complex two-plane Grassmannians whose Jacobi operators or the Jacobi corresponding to the directions in the distribution are of Codazzi type if they satisfy a further condition. We obtain that that they must be either of type (A) or of type (B) (see [2]), but no one of these satisfies our condition. As a consequence, we obtain the non-existence of Hopf real hypersurfaces in such ambient spaces whose Jacobi operators corresponding to -directions are parallel with the same further condition.展开更多
It has been shown, under certain conditions on the Gauss curvature, every totally real surface of the Cayley projective plane with parallel mean curvature vector is either flat or totally geodesic.
The optimal plane for measurement of the right ventricular (RV) volumes by real-time three-dimensional echocardiography (RT3DE) was determined and the feasibility and accuracy of RT3DE in studying RV systolic function...The optimal plane for measurement of the right ventricular (RV) volumes by real-time three-dimensional echocardiography (RT3DE) was determined and the feasibility and accuracy of RT3DE in studying RV systolic function was assessed. RV “Full volume” images were acquired by RT3DE in 22 healthy subjects. RV end-diastolic volumes (RVEDV) and end-systolic volumes (RVESV) were outlined using apical biplane, 4-plane, 8-plane, 16-plane offline separately. RVSV and RVEF were calculated. Meanwhile tricuspid annual systolic excursion (TASE) was measured by M-mode echo. LVSV was outlined by 2-D echo according to the biplane Simpson's rule. The results showed: (1) There was a good correlation between RVSV measured from series planes and LVSV from 2-D echo (r=0.73; r=0.69; r=0.63; r=0.66, P<0.25—0.0025); (2) There were significant differences between RVEDV in biplane and those in 4-, 8-, 16-plane (P<0.001). There was also difference between RV volume in 4-plane and that in 8-plane (P<0.05), but there was no significant difference between RV volume in 8-plane and that in 16-plane (P>0.05); (3) Inter-observers and intro-observers variability analysis showed that there were close agreements and relations for RV volumes (r=0.986, P<0.001; r=0.93, P<0.001); (4) There was a significantly positive correlation of TASE to RVSV and RVEF from RT3DE (r=0.83; r=0.90). So RV volume measures with RT3DE are rapid, accurate and reproducible. In view of RV's complex shape, apical 8-plane method is better in clinical use. It may allow early detection of RV systolic function.展开更多
Room-temperature terahertz （THz） detectors indicate a great potential in the imaging application because of their real-time, compact bulk, and wide spectral band responding characteristics. THz detectors with differ...Room-temperature terahertz （THz） detectors indicate a great potential in the imaging application because of their real-time, compact bulk, and wide spectral band responding characteristics. THz detectors with different dimensions based on a micro-bridge structure have been designed and fabricated to get optimized micro-bolometer parameters from the test results of membrane deformation. A nanostructured titanium （Ti） thin film absorber is integrated in the micro-bridge structure of the VOx micro-bolometer by a combined process of magnetron sputtering and reactive ion etching （RIE）, and its improvement of THz absorption is verified by an optical characteristics mesurement. Continuous-wave THz detection and imaging are demonstrated by using a 2.52 THz far infrared CO2 laser and a 320x240 vanadium oxide micro-bolometer focal plane array with an optimized cell structure. With this detecting system, THz imaging of metal concealed in a wiping cloth and an envelope is demonstrated, respectively.展开更多
目的探讨实时三平面超声心动图(RT-3PE)测量离体猪心室壁瘤心模型的左室容积,分析此方法的可行性与准确性。方法应用10%福尔马林液固定17个模拟室壁瘤形成的离体猪心,将其浸入水槽中,用二维超声心动图的双平面Simpson法RT-3PE测量左室容...目的探讨实时三平面超声心动图(RT-3PE)测量离体猪心室壁瘤心模型的左室容积,分析此方法的可行性与准确性。方法应用10%福尔马林液固定17个模拟室壁瘤形成的离体猪心,将其浸入水槽中,用二维超声心动图的双平面Simpson法RT-3PE测量左室容积,其值分别与左室注水的真实容积进行对比研究。结果线性回归分析表明实时三平面成像所测左室容积与其真实容积相关性较好(r=0.92,P<0.01);方差分析表明两者间差异无统计学意义(P>0.05)。二维超声心动图双平面Simpson法所测左室容积与真实容积亦具有良好的相关性(r=0.82,P<0.01),但两者间有显著性差异(P<0.05)。Altman and Bland一致性分析显示RT-3PE所测容积与实测容积之间的一致性明显高于二维超声心动图。结论RT-3PE是一快速、准确测量左室室壁瘤左室容积的新方法。展开更多
基金Project (No. MTM2005-08690-C02-02) partially supported by the Spanish Ministry of Science and Innovation Grant
文摘We introduce a new algebraic approach dealing with the problem of computing the topology of an arrangement of a finite set of real algebraic plane curves presented implicitly. The main achievement of the presented method is a complete avoidance of irrational numbers that appear when using the sweeping method in the classical way for solving the problem at hand. Therefore, it is worth mentioning that the efficiency of the proposed method is only assured for low-degree curves.
文摘Hastening transmission by efficiently providing compression is our goal in this work. Image compression consists in reducing information size representing an image. Elimination of redundancies and non-pertinent information enables memory space minimization and thus fast data transmission. Optics can offer an alternative choice to overcome the limitation of numerical compression algorithms. In this paper, we propose real-time optical image compression using a real Fourier plane to save time required for compression by using the principles of coherent optics. Digital and optical simulation results are presented and analyzed. An optical compression decompression setup is demonstrated using two different SLMs (SEIKO and DisplayTech). The purpose of this method is to simplify our earlier method, improve the quality of reconstructed image, and avoid the disadvantages of numerical algorithms.
文摘We prove the non-existence of Hopf real hypersurfaces in complex two-plane Grassmannians whose Jacobi operators or the Jacobi corresponding to the directions in the distribution are of Codazzi type if they satisfy a further condition. We obtain that that they must be either of type (A) or of type (B) (see [2]), but no one of these satisfies our condition. As a consequence, we obtain the non-existence of Hopf real hypersurfaces in such ambient spaces whose Jacobi operators corresponding to -directions are parallel with the same further condition.
文摘It has been shown, under certain conditions on the Gauss curvature, every totally real surface of the Cayley projective plane with parallel mean curvature vector is either flat or totally geodesic.
文摘The optimal plane for measurement of the right ventricular (RV) volumes by real-time three-dimensional echocardiography (RT3DE) was determined and the feasibility and accuracy of RT3DE in studying RV systolic function was assessed. RV “Full volume” images were acquired by RT3DE in 22 healthy subjects. RV end-diastolic volumes (RVEDV) and end-systolic volumes (RVESV) were outlined using apical biplane, 4-plane, 8-plane, 16-plane offline separately. RVSV and RVEF were calculated. Meanwhile tricuspid annual systolic excursion (TASE) was measured by M-mode echo. LVSV was outlined by 2-D echo according to the biplane Simpson's rule. The results showed: (1) There was a good correlation between RVSV measured from series planes and LVSV from 2-D echo (r=0.73; r=0.69; r=0.63; r=0.66, P<0.25—0.0025); (2) There were significant differences between RVEDV in biplane and those in 4-, 8-, 16-plane (P<0.001). There was also difference between RV volume in 4-plane and that in 8-plane (P<0.05), but there was no significant difference between RV volume in 8-plane and that in 16-plane (P>0.05); (3) Inter-observers and intro-observers variability analysis showed that there were close agreements and relations for RV volumes (r=0.986, P<0.001; r=0.93, P<0.001); (4) There was a significantly positive correlation of TASE to RVSV and RVEF from RT3DE (r=0.83; r=0.90). So RV volume measures with RT3DE are rapid, accurate and reproducible. In view of RV's complex shape, apical 8-plane method is better in clinical use. It may allow early detection of RV systolic function.
基金supported by the National Science Funds for Creative Research Groups of China under Grant No.61421002National High Technology Research and Development Program under Grant No.2015AA8123014
文摘Room-temperature terahertz （THz） detectors indicate a great potential in the imaging application because of their real-time, compact bulk, and wide spectral band responding characteristics. THz detectors with different dimensions based on a micro-bridge structure have been designed and fabricated to get optimized micro-bolometer parameters from the test results of membrane deformation. A nanostructured titanium （Ti） thin film absorber is integrated in the micro-bridge structure of the VOx micro-bolometer by a combined process of magnetron sputtering and reactive ion etching （RIE）, and its improvement of THz absorption is verified by an optical characteristics mesurement. Continuous-wave THz detection and imaging are demonstrated by using a 2.52 THz far infrared CO2 laser and a 320x240 vanadium oxide micro-bolometer focal plane array with an optimized cell structure. With this detecting system, THz imaging of metal concealed in a wiping cloth and an envelope is demonstrated, respectively.
文摘目的探讨实时三平面超声心动图(RT-3PE)测量离体猪心室壁瘤心模型的左室容积,分析此方法的可行性与准确性。方法应用10%福尔马林液固定17个模拟室壁瘤形成的离体猪心,将其浸入水槽中,用二维超声心动图的双平面Simpson法RT-3PE测量左室容积,其值分别与左室注水的真实容积进行对比研究。结果线性回归分析表明实时三平面成像所测左室容积与其真实容积相关性较好(r=0.92,P<0.01);方差分析表明两者间差异无统计学意义(P>0.05)。二维超声心动图双平面Simpson法所测左室容积与真实容积亦具有良好的相关性(r=0.82,P<0.01),但两者间有显著性差异(P<0.05)。Altman and Bland一致性分析显示RT-3PE所测容积与实测容积之间的一致性明显高于二维超声心动图。结论RT-3PE是一快速、准确测量左室室壁瘤左室容积的新方法。
