- 标题
- 摘要
- 关键词
- 实验方案
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Cu/Sb Codoping for Tuning Carrier Concentration and Thermoelectric Performance of GeTe-Based Alloys with Ultralow Lattice Thermal Conductivity
摘要： Pristine GeTe shows promising thermoelectric performance but is limited by the high carrier concentration (nH) from Ge vacancies and thermal conductivity. Herein, Cu/Sb was chosen as codopants to suppress the high nH and to decrease thermal conductivity. In this condition, a promising zT of ～1.62 under 773 K was acquired in the Ge0.85Te(CuSb)0.075 system proposed in this paper/work. Results show that as the dopant concentration increases, the power factor rises due to the reduction of the nH to ～1 × 1020 cm?3. Apart from this, the total thermal conductivity also declines from ～7.4 W m?1 K?1 to ～1.59 W m?1 K?1 originating from an ultralow lattice thermal conductivity, in which the multiscatter mechanism from grain boundaries and point defect disperses the frequency phonons di?erently. The ?ndings in this paper combine thermal and electronic strategies and lay the foundation to develop Pb-free thermoelectric materials.
关键词： multiscatter mechanism,Cu/Sb codoped GeTe,thermoelectric materials,ultralow lattice thermal conductivity,zT value,carrier concentration,Seebeck coefficient
更新于2025-11-14 17:03:37
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Image Denoising Using Block-Rotation-Based SVD Filtering in Wavelet Domain
摘要： This paper proposes an image denoising method using singular value decomposition (SVD) with block-rotation-based operations in wavelet domain. First, we decompose a noisy image to some sub-blocks, and use the single-level discrete 2-D wavelet transform to decompose each sub-block into the low-frequency image part and the high-frequency parts. Then, we use SVD and rotation-based SVD with the rank-1 approximation to filter the noise of the different high-frequency parts, and get the denoised sub-blocks. Finally, we reconstruct the sub-block from the low-frequency part and the filtered the high-frequency parts by the inverse wavelet transform, and reorganize each denoised sub-blocks to obtain the final denoised image. Experiments show the effectiveness of this method, compared with relevant methods.
关键词： singular value decomposition,threshold denoising,structural similarity index,position,peak signal-to-noise ratio,image denoising
更新于2025-09-23 15:23:52
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Non-destructive assessment of the oxidative stability of intact macadamia nuts during the drying process by near-infrared spectroscopy
摘要： We have developed a rapid non-destructive method to assess the oxidative stability of intact macadamia nuts using near-infrared spectroscopy (NIRS). Intact macadamia nuts of the cultivars HAES 344 'Kau', HAES 660 'Keaau', IAC 4-12 B, and IAC Campinas B were harvested and immediately oven-dried for 4 days at 30 °C, 2 days at 40 °C, and 1 day at 60 °C to achieve 1.5% kernel moisture content. At each drying step nuts were withdrawn and their moisture content, peroxide value (PV), and acidity index (AI) determined. The best partial least square model for PV prediction was obtained using the Savitzky-Golay (SG) second derivative resulting in a standard error of prediction (SEP) of 0.55 meq·kg?1 and a coefficient of determination (R2 C) of 0.57. The best AI prediction-model result was obtained using the SG second derivative (SEP = 0.14%, R2 C = 0.29). Based on the maximum quality limits of 3 meq·kg?1 for PV and 0.5% for AI, the SEP values represented 18% and 28%, respectively. Therefore, the prediction method can be considered useful since the errors are lower than the quality limits. Thus, NIRS can be used to assess the oxidative stability of intact macadamia kernels.
关键词： principal component analysis,peroxide value,Macadamia integrifolia Maiden & Betche,acidity index
更新于2025-09-23 15:23:52
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Quaternion-based weighted nuclear norm minimization for color image denoising
摘要： The quaternion method plays an important role in color image processing, because it represents the color image as a whole rather than as a separate color space component, thus naturally handling the coupling among color channels. The weighted nuclear norm minimization (WNNM) scheme assigns different weights to different singular values, leading to more reasonable image representation method. In this paper, we propose a novel quaternion weighted nuclear norm minimization (QWNNM) model and algorithm under the low rank sparse framework. The proposed model represents the color image as a low rank quaternion matrix, where quaternion singular value decomposition can be calculated by its equivalent complex matrix. We solve the QWNNM by adaptively assigning different singular values with different weights. Color image denoising is implemented by QWNNM based on non-local similarity priors. In this new color space, the inherent color structure can be well preserved during image reconstruction. For high noise levels, we apply a Gaussian lowpass filter (LPF) to the noisy image as a preprocessing before QWNNM, which reduces the iteration numbers and improves the denoised results. The experimental results clearly show that the proposed method outperforms K-SVD, QKSVD and WNNM in terms of both quantitative criteria and visual perceptual.
关键词： Quaternion singular value decomposition,Non-local similarity priors,Quaternion weighted nuclear norm minimization,Low rank,Color image denoising
更新于2025-09-23 15:23:52
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An Alternative Formulation for Optimum TMD Parameters Based on Equal Eigen Value Criteria
摘要： Closed form expressions for optimum Tuned Mass Damper (TMD) parameters are obtained by equating Eigen values of two modes and there is no need of any trial and error approach as used in earlier studies. For certain values of damping of main system and mass ratio, two sets of optimum parameters exist. For some other range of damping and mass ratio, modes become fully damped. In this range, optimum TMDs do not exist, and this happens for TMDs with large mass. The optimum TMD is shown to be quite robust and gives lesser TMD displacement as compared to optimum TMDs of earlier studies.
关键词： Equal modal frequency,Equal Eigen Value,Fully damped modes,Frequency response function,Optimum Tuned Mass Damper,Equal modal damping
更新于2025-09-23 15:23:52
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Weak-value amplification of photon-number operators in the optomechanical interaction
摘要： An experimental proposal is presented in which dark port postselection together with weak measurements are used to enlarge the radiation pressure effect of a single photon on a mechanical oscillator placed in the middle of a Fabry-Pérot cavity and initialized in the ground state. By preparing and postselecting the photon (the system) in two quasiorthogonal states, the weak value of the radiation force operator can lie outside the eigenvalue spectrum, producing a large shift on the wave function of the mechanical oscillator (the measuring device) in the position representation. Consequently, the effect of a single photon on the average position of the oscillator can be amplified as compared to the effect caused by a photon without postselection, i.e., only preselected. The strong measurement scenario is also analyzed. In this case, a higher amplification effect is achieved and the mean position of the oscillator can reach the level of the zero-point fluctuations, but the postselection probabilities are smaller. Finally, the situation in which the oscillator starts in a thermal equilibrium state is studied. In this case, the amplification of the average position remains the same, i.e., proportional to the weak value, but the signal-to-noise ratio is reduced by a factor that depends on the average number of thermal phonons.
关键词： weak measurements,weak-value amplification,optomechanics,postselection,radiation pressure
更新于2025-09-23 15:23:52
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Interference Suppression of Partially Overlapped Signals Using GSVD and Orthogonal Projection
摘要： In order to solve the problem in Automatic Identification System (AIS) that the signal in the target slot cannot be correctly received due to partial overlap of signals in adjacent time slots, the paper introduces a new criterion: maximum expected signal power (MESP) and proposes a novel beamforming algorithm based on generalized singular value decomposition (GSVD) and orthogonal projection. The algorithm employs GSVD to estimate the signal subspace, and adopts orthogonal projection to project the received signal onto the orthogonal subspace of the non-target signal. Then, beamforming technique is used to maximize the output power of the target signal on the basis of MESP. Theoretical analysis and simulation results show the effectiveness of the proposed algorithm.
关键词： blind beamforming,automatic identification system,partial overlapping,generalized singular value decomposition,orthogonal projection
更新于2025-09-23 15:23:52
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Adaptive LSB quantum watermarking method using tri-way pixel value differencing
摘要： As an important way to protect copyright by embedding watermark in digital images, quantum watermarking catches more and more attentions. In this study, a novel quantum watermarking method on the basis of tri-way pixel value differencing and modified least significant bit (LSB) substitution is proposed. A quantum cover image using the novel-enhanced quantum image representation is partitioned into non-overlapping 2 × 2 blocks with four pixels firstly. To classify the block as a smooth area or an edge area, the tri-way pixel value differences are calculated and compared with a predefined threshold. The quantum watermark image, which is expanded and scrambled, is then embedded into a quantum cover image by the k-bit LSB substitution method, where k is decided by the level of each block. The embedded quantum watermark can be extracted from the quantum stego-image without the assistance of original quantum cover image. Theoretical analysis and simulation-based experiments demonstrate both the feasibility and capabilities of the proposed quantum watermarking method, which has good visual quality, better robustness, and higher security.
关键词： Pixel value difference,Visual quality,Quantum image watermarking,Least significant bit
更新于2025-09-23 15:23:52
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Clinical Value of Positron Emission Tomography-Computed Tomography Combined with Ultrasound in Detection of Primary Tumors in Patients with Malignant Ascites
摘要： Objective: To investigate and discuss the clinical value of positron emission tomography-computed tomography (PET-CT) combined with ultrasound in detection of primary tumors in patients with malignant ascites (MA). Materials and Methods: A total of 122 malignant tumor patients with ascites as the initial symptom and 48 patients with benign ascites were enrolled in this study. All patients underwent PET-CT and abdominal B-ultrasound examinations. The corresponding specificity, sensitivity, accuracy rate, positive predictive value, and negative predictive value of PET-CT, abdominal B-ultrasound, and combined detection group were recorded, respectively, with pathological findings as the gold standards. Statistical Product and Service Solutions 17.0 software was used for statistical analysis. p < 0.05 suggested that the difference was statistically significant. Results: The detection rate of primary foci through PET-CT was 79.5%, of which the detection rate of primary foci of MA derived from gastric cancer was the highest. The detection rate of primary foci through B-ultrasound was 62.5%, which is the highest for MA derived from ovarian cancer. B-ultrasound had the highest specificity in diagnosing the primary foci of MA (73.2%), PET-CT had the highest sensitivity in diagnosing the primary foci of MA (91.7%), and PET-CT combined with abdominal B-ultrasound had the highest sensitivity and accuracy in diagnosing the primary foci of MA (98.1% and 89.1%, respectively). The diagnostic accuracy rate of B-ultrasound was the highest in detecting tumors >5 cm (77.0%), whereas that of PET-CT was the highest in detecting tumors of 3–5 cm (84.2%). Conclusion: The PET-CT combined with ultrasound is conducive to improving the diagnostic efficiency for primary tumors in patients with MA.
关键词： ultrasound,malignant ascites,PET-CT,clinical value
更新于2025-09-23 15:23:52
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[IEEE 2018 3rd International Conference for Convergence in Technology (I2CT) - Pune (2018.4.6-2018.4.8)] 2018 3rd International Conference for Convergence in Technology (I2CT) - Generalized Method for Stego Pixel Optimization Using Slide Value Algorithm
摘要： This paper presents a general algorithm for optimization of pixel value after data is embedded into the pixel. The simplest method is least-significant-bit substitution, embeds data in the least significant bits of the cover image. It introduces a small distortion in the cover image with the disadvantage that post processing may destroy the hidden data easily. Many data hiding techniques use higher bit position to hide data for security reasons at the cost of increased cover distortion. Distortion is increased by twice the value as hiding bit location is shifted one position towards the most significant bit. Many techniques involving bit manipulation are used to optimize the value of stego pixel byte without affecting the hidden data so that the stego byte value has minimum distortion as compared to the original value in cover image. The proposed method uses sliding value algorithm to optimize the stego pixel byte. It is divided into two parts, slide up and slide down algorithm. The best value obtained from these two sub-algorithms is taken as the final optimized value. The algorithm completely minimizes the distortion of stego byte hence increasing robustness and security. The method leaves no scope for further optimization of stego pixel value and the results show better performance.
关键词： Data hiding,Up-slide,Down-slide,Sliding value,moderate bit
更新于2025-09-23 15:23:52