共查询到20条相似文献,搜索用时 31 毫秒
1.
High-Q factor three-dimensional inductors 总被引:2,自引:0,他引:2
Piernas B. Nishikawa K. Kamogawa K. Nakagawa T. Araki K. 《Microwave Theory and Techniques》2002,50(8):1942-1949
In this paper, the great flexibility of three-dimensional (3-D) monolithic-microwave integrated-circuit technology is used to improve the performance of on-chip inductors. A novel topology for high-Q factor spiral inductor that can be implemented in a single or multilevel configuration is proposed. Several inductors were fabricated on either silicon substrate (/spl rho/ = 30 /spl Omega/ /spl middot/ cm) or semi-insulating gallium-arsenide substrate demonstrating, more particularly, for GaAs technology, the interest of the multilevel configuration. A 1.38-nH double-level 3-D inductor formed on an Si substrate exhibits a very high peak Q factor of 52.8 at 13.6 GHz and a self-resonant frequency as high as 24.7 GHz. Our 4.9-nH double-level GaAs 3-D inductor achieves a peak Q factor of 35.9 at 4.7 GHz and a self-resonant frequency of 8 GHz. For each technology, the performance limits of the proposed inductors in terms of quality factor are discussed. Guidelines for the optimum design of 3-D inductors are provided for Si and GaAs technologies. 相似文献
2.
建立了HgCdTe红外焦平面器件的多膜层理论模型,利用有限元分析的方法,对10.6μm激光辐照下HgCdTe红外焦平面器件的升温情况与热应力分布情况进行模拟,并通过参考已有文献的实验结果,验证了理论模型的合理性。理论分析结果表明:激光作用时探测器的温度场变化剧烈,200 W/cm2连续激光作用1 s后,HgCdTe感光层所受热应力为-986 MPa;脉宽100 ns,功率密度15 MW/cm2脉冲激光作用后,HgCdTe感光层所受热应力为-1300 MPa,都比器件制造过程中由于热失配而产生的热应力大;应力损伤发生的概率增大,可能比热损伤先发生,是HgCdTe红外焦平面器件激光损伤中的重要原因。 相似文献
3.
《IEEE transactions on medical imaging》1997,16(5):630-641
The recovery of a three-dimensional (3-D) model from a sequence of two-dimensional (2-D) images is very useful in medical image analysis. Image sequences obtained from the relative motion between the object and the camera or the scanner contain more 3-D information than a single image. Methods to visualize the computed tomograms can be divided into two approaches: the surface rendering approach and the volume rendering approach. In this paper, a new surface rendering method using optical flow is proposed. Optical flow is the apparent motion in the image plane produced by the projection of real 3-D motion onto the 2-D image. The 3-D motion of an object can be recovered from the optical-flow field using additional constraints. By extracting the surface information from 3-D motion, it is possible to obtain an accurate 3-D model of the object. Both synthetic and real image sequences have been used to illustrate the feasibility of the proposed method. The experimental results suggest that the proposed method is suitable for the reconstruction of 3-D models from ultrasound medical images as well as other computed tomograms 相似文献
4.
Tai Suk Kim Min Young Chung Dan Keun Sung Sengoku M. 《Vehicular Technology, IEEE Transactions on》1998,47(2):546-557
To efficiently plan future personal communications services (PCSs), we need to solve various mobility/traffic problems in one-dimensional (1-D), two-dimensional (2-D), and three-dimensional (3-D) micro or picocell environments. However, mobility/traffic problems have thus far primarily been studied in 1-D and 2-D cell structures. In this paper, we extend the previous mobility modeling from 1-D or 2-D space to 3-D indoor building environments by considering the proper boundary conditions on each floor and analytically modeling mobility in multi-story buildings to estimate the number of handoffs. We then propose a blocking probability model with mobility as a traffic model in 3-D indoor environments. Utilizing this model, we can obtain the required number of channels per cell under the given blocking probability constraint. These results can be utilized in planning the networks of future PCSs 相似文献
5.
Camera constraint-free view-based 3-D object retrieval 总被引:1,自引:0,他引:1
Gao Y Tang J Hong R Yan S Dai Q Zhang N Chua TS 《IEEE transactions on image processing》2012,21(4):2269-2281
Recently, extensive research efforts have been dedicated to view-based methods for 3-D object retrieval due to the highly discriminative property of multiviews for 3-D object representation. However, most of state-of-the-art approaches highly depend on their own camera array settings for capturing views of 3-D objects. In order to move toward a general framework for 3-D object retrieval without the limitation of camera array restriction, a camera constraint-free view-based (CCFV) 3-D object retrieval algorithm is proposed in this paper. In this framework, each object is represented by a free set of views, which means that these views can be captured from any direction without camera constraint. For each query object, we first cluster all query views to generate the view clusters, which are then used to build the query models. For a more accurate 3-D object comparison, a positive matching model and a negative matching model are individually trained using positive and negative matched samples, respectively. The CCFV model is generated on the basis of the query Gaussian models by combining the positive matching model and the negative matching model. The CCFV removes the constraint of static camera array settings for view capturing and can be applied to any view-based 3-D object database. We conduct experiments on the National Taiwan University 3-D model database and the ETH 3-D object database. Experimental results show that the proposed scheme can achieve better performance than state-of-the-art methods. 相似文献
6.
Pole-Shang Lin Ching-Yuan Wu 《Electron Devices, IEEE Transactions on》1991,38(6):1376-1383
A new simplified two-dimensional model for the threshold voltage of MOSFETs is derived in terms of simple characteristic functions. These characteristic functions are transformed from the exact series solution of the two-dimensional Poisson's equation, in which the effects of a nonuniformly doped substrate and a finite graded source-drain junction depth are included. In this model, charge-screening effects are proposed to account for the weak dependence of the threshold voltage on the substrate bias for short-channel MOSFETs, and exact source and drain boundary potentials can be approximated by their equivalent power functions. The accuracy of the simplified 2-D model is verified by 2-D numerical analysis. Moreover, comparisons between the simplified 2-D model and the experimental results are made, and good agreement is obtained for wide ranges of channel lengths, applied substrate, and drain biases 相似文献
7.
Tai Suk Kim Jae Kyun Kwon San Keun Sung 《Vehicular Technology, IEEE Transactions on》2000,49(5):1633-1640
To efficiently plan future personal communications services, we need to solve various mobility/traffic problems in one-dimensional (1-D), two-dimensional (2-D), and three-dimensional (3-D) micro- or pico-cell environments. Although many users exhibit vertical motion inside elevators in high-rise buildings, there have been no studies regarding cell planning which take into account vertical motion with elevators. We extend the previous 3-D indoor mobility modeling by considering the proper boundary conditions on each floor and vertical motions through elevators and modeling mobility in high-rise buildings in order to estimate the number of handoffs. We then propose a blocking probability model with mobility as a traffic model in 3-D indoor environments. Using this model, we can obtain the required number of channels per cell under the given blocking probability constraint. These results can be used in planning the networks of future personal communications services 相似文献
8.
《Microwave and Wireless Components Letters, IEEE》2009,19(6):365-367
9.
A MAP framework for tag line detection in SPAMM data using Markov random fields on the B-spline solid 总被引:1,自引:0,他引:1
Magnetic resonance (MR) tagging is a technique for measuring heart deformations through creation of a stripe grid pattern on cardiac images. In this paper, we present a maximum a posteriori (MAP) framework for detecting tag lines using a Markov random field (MRF) defined on the lattice generated by three-dimensional (3-D) and four-dimensional (4-D) (3-D + t) uniform sampling of B-spline models. In the 3-D case, MAP estimation is cast for detecting present tag features in the current image given an initial solid from the previous frame (the initial undeformed solid is manually positioned by clicking on corner points of a cube). The method also allows the parameters of the solid model, including the number of knots and the spline order, to be adjusted within the same framework. Fitting can start with a solid with less knots and lower spline order and proceed to one with more knots and/or higher order so as to achieve more accuracy and/or higher order of smoothness. In the 4-D case, the initial model is considered to be the linear interpolation of a sequence of optimal solids obtained from 3-D tracking. The same framework proposed for the 3-D case can once again be applied to arrive at a 4-D B-spline model with a higher temporal order. 相似文献
10.
Kuo-Feng You Ching-Yuan Wu 《Electron Devices, IEEE Transactions on》1999,46(6):1174-1179
A significant mismatch occurs when we predict the gate-induced drain leakage current (GIDL) by using existing one-dimensional (l-D) models. It's found that the gate-induced drain leakage current is attributed to not only the vertical field but also the lateral field near the drain-to-gate overlap region. Therefore, a new quasi-two-dimensional (quasi-2-D) model considering both the lateral and vertical fields for predicting the gate-induced drain leakage current is proposed by using the drain-induced energy-barrier reduction in our model. The calculated results using the developed quasi-2-D model are in good agreement with measured values for a wide range of gate and drain biases. Therefore, the proposed new model can be used to simulate the hot-carrier band-to-band tunneling current for p-channel flash memory device 相似文献
11.
The initial conception of a model-based analysis synthesis image coding (MBASIC) system is described and a construction method for a three-dimensional (3-D) facial model that includes synthesis methods for facial expressions is presented. The proposed MBASIC system is an image coding method that utilizes a 3-D model of the object which is to be reproduced. An input image is first analyzed and an output image using the 3-D model is then synthesized. A very low bit rate image transmission can be realized because the encoder sends only the required analysis parameters. Output images can be reconstructed without the noise corruption that reduces naturalness because the decoder synthesizes images from a similar 3-D model.
In order to construct a 3-D model of a person's face, a method is developed which uses a 3-D wire frame face model. A full-face image is then projected onto this wire frame model. For the synthesis of facial expressions two different methods are proposed; a clip-and-paste method and a facial structure deformation method. 相似文献
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Power supply noise in three-dimensional integrated circuits (3-D ICs) considering scaled CMOS and through silicon via (TSV) technologies is the focus of this paper. A TSV and inductance aware cell-based 3-D power network model is proposed and evaluated. Constant TSV aspect ratio and constant TSV area penalty scaling, as two scenarios of TSV technology scaling, are discussed. A comparison of power noise among via-first, via-middle, and via-last TSV technologies with CMOS scaling is also presented. When the TSV technology is a primary bottleneck in high performance 3-D ICs, an increasing TSV area penalty should be adopted to produce lower power noise. As a promising TSV technology, via-middle TSVs are shown to produce the lowest power noise with CMOS technology scaling. 相似文献
15.
Reconstruction of a 3-D face model from a single 2-D face image is fundamentally important for face recognition and animation because the 3-D face model is invariant to changes of viewpoint, illumination, background clutter, and occlusions. Given a coupled training set that contains pairs of 2-D faces and the corresponding 3-D faces, we train a novel coupled radial basis function network (C-RBF) to recover the 3-D face model from a single 2-D face image. The C-RBF network explores: 1) the intrinsic representations of 3-D face models and those of 2-D face images; 2) mappings between a 3-D face model and its intrinsic representation; and 3) mappings between a 2-D face image and its intrinsic representation. Since a particular face can be reconstructed by its nearest neighbors, we can assume that the linear combination coefficients for a particular 2-D face image reconstruction are identical to those for the corresponding 3-D face model reconstruction. Therefore, we can reconstruct a 3-D face model by using a single 2-D face image based on the C-RBF network. Extensive experimental results on the BU3D database indicate the effectiveness of the proposed C-RBF network for recovering the 3-D face model from a single 2-D face image. 相似文献
16.
A novel approach is proposed to image 3-D cardiac electrical activity from intracavity electrical recordings with the aid of a catheter. The feasibility and performance were evaluated by computer simulation studies, where a 3-D cellular-automaton heart model and a finite-element thorax volume conductor model were utilized. The finite-element method (FEM) was used to simulate the intracavity recordings induced by a single-site and dual-site pacing protocol. The 3-D ventricular activation sequences as well as the locations of the initial activation sites were inversely estimated by minimizing the dissimilarity between the intracavity potential "measurements" and the model-generated intracavity potentials. Under single-site pacing, the relative error (RE) between the true and estimated activation sequences was 0.03 +/- 0.01 and the localization error (LE) (of the initiation site) was 1.88 +/- 0.92 mm, as averaged over 12 pacing trials when considering 25 microV additive measurement noise using 64 catheter electrodes. Under dual-site pacing, the RE was 0.04 +/- 0.01 over 12 pacing trials and the LE over 24 initial pacing sites was 2.28 +/- 1.15 mm, when considering 25 microV additive measurement noise using 64 catheter electrodes. The proposed 3-D cardiac electrical imaging approach using intracavity electrical recordings was also tested under various simulated conditions and robust inverse solutions obtained. The present promising simulation results suggest the feasibility of obtaining 3-D information of cardiac electrical activity from intracavity recordings. The application of this inverse method has the potential of enhancing electrocardiographic mapping by catheters in electrophysiology laboratories, aiding cardiac resynchronization therapy, and other clinical applications. 相似文献
17.
Ernst T. Ritzenthaler R. Faynot O. Cristoloveanu S. 《Electron Devices, IEEE Transactions on》2007,54(6):1366-1375
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Seung Wook Yoon Lim S.Y.L. Viswanath A.G.K. Thew S. Tai Chong Chai Kripesh V. 《Advanced Packaging, IEEE Transactions on》2008,31(1):127-134
Solder joint reliability of 3-D silicon carrier module were investigated with temperature cycle and drop impact test. Mechanical simulation was carried out to investigate the solder joint stress using finite element method (FEM), whose 3-D model was generated and solder fatigue model was used. According to the simulation results, the stress involved between flip chip and Si substrate was negligible but stress is more concentrated between Si carriers to printed circuit board (PCB) solder joint area. Test vehicles were fabricated using silicon fabrication processes such as DRIE, Cu via plating, SiO deposition, metal deposition, lithography, and dry or wet etching. After flip chip die and silicon substrate fabrication, they were assembled by flip chip bonding equipment and 3-D silicon stacked modules with three silicon substrate and flip chip dies were fabricated. Daisy chains were formed between flip chip dies and silicon substrate and resistance measurement was carried out with temperature cycle test (C, 2 cycles/h). The tested flip chip test vehicles passed T/C 5000 cycles and showed robust solder joint reliability without any underfill material. Drop test was also carried out by JEDEC standard method. More details on test vehicle fabrication and reliability test results would be presented in the paper. 相似文献
20.
Brost A Wimmer A Liao R Bourier F Koch M Strobel N Kurzidim K Hornegger J 《IEEE transactions on medical imaging》2012,31(4):870-881
Fluoroscopic overlay images rendered from preoperative volumetric data can provide additional anatomical details to guide physicians during catheter ablation procedures for treatment of atrial fibrillation (AFib). As these overlay images are often compromised by cardiac and respiratory motion, motion compensation methods are needed to keep the overlay images in sync with the fluoroscopic images. So far, these approaches have either required simultaneous biplane imaging for 3-D motion compensation, or in case of monoplane X-ray imaging, provided only a limited 2-D functionality. To overcome the downsides of the previously suggested methods, we propose an approach that facilitates a full 3-D motion compensation even if only monoplane X-ray images are available. To this end, we use a training phase that employs a biplane sequence to establish a patient specific motion model. Afterwards, a constrained model-based 2-D/3-D registration method is used to track a circumferential mapping catheter. This device is commonly used for AFib catheter ablation procedures. Based on the experiments on real patient data, we found that our constrained monoplane 2-D/3-D registration outperformed the unconstrained counterpart and yielded an average 2-D tracking error of 0.6 mm and an average 3-D tracking error of 1.6 mm. The unconstrained 2-D/3-D registration technique yielded a similar 2-D performance, but the 3-D tracking error increased to 3.2 mm mostly due to wrongly estimated 3-D motion components in X-ray view direction. Compared to the conventional 2-D monoplane method, the proposed method provides a more seamless workflow by removing the need for catheter model re-initialization otherwise required when the C-arm view orientation changes. In addition, the proposed method can be straightforwardly combined with the previously introduced biplane motion compensation technique to obtain a good trade-off between accuracy and radiation dose reduction. 相似文献