分类： 物理学 >> 凝聚态:结构、力学和热性能 提交时间： 2025-04-09
摘要： Electron-diffraction patterns with 5-fold rotational symmetry of experimental alloy phases are assumed to be produced by periodic structures. One three-dimensional periodic structure is pre sented based on two kind polyhedrons. The structure can be used as one orthorhombic cell atomic model to describe the alloy phases. The Fourier-transform patterns of the model are simulated along six “symmetry directions”. The chemical composition of the model is similar to that of the Al-Mn alloy phase. Details of the motivations and approaches that lead to these models are discussed. This study suggests that non classical periodic structures are also well candidates to describe quasicrystals. Further studies in this area are encouraged.
分类： 计算机科学 >> 自然语言理解与机器翻译 提交时间： 2024-11-25
摘要： Large language models (LLMs) have showcased exceptional capabilities across various natural language processing (NLP) tasks in recent years, such as machine translation, text summarization, and question answering. Despite their impressive performance, the deployment of these models on edge devices, such as mobile phones, IoT devices, and edge computing nodes, is significantly hindered by their substantial computational and memory requirements. This survey provides a comprehensive overview of the state-of-the-art techniques and strategies for enabling efficient inference of LLMs on edge devices. We explore approaches including the development of small language models (SLMs), model compression techniques, inference optimization strategies, and dedicated frameworks for edge deployment. Our goal is to highlight the advancements and ongoing challenges in this field, offering valuable insights for researchers and practitioners striving to bring the power of LLMs to edge environments.
分类： 数学 >> 应用数学 分类： 物理学 >> 交叉学科物理及相关领域的科学与技术 提交时间： 2023-07-04
摘要： 伪随机数发生器（PRNG）广泛应用于许多领域，尤其是在密码应用中。设计欠佳的PRNG生成的序列将导致其密钥较弱从而可能泄漏被隐藏的信息。基于Golomb对理想伪随机序列的假设和FIPS 140-2随机性检验准则，本文首次提出了一种改进伪随机序列伪随机性能的新方法。其次，用广义同步定理、Henon映射、logistic映射和tube射构造了一个新的8维混沌广义同步系统（8DCGSS）。然后使用8DCGSS设计了一个混沌PRNG（CPRNG）。CPRNG的密钥空间大于2^{1117}。用FIPS 140-2随机性测试规范和广义FIPS 140-2随机性测试规范分别检测了CPRNG、Matlab PRNG、RC4算法和m序列分别生成的1000条20 000比特长的密钥流的通过率，应用广义FIPS 140-2随机性测试规范分别评估了改进的密钥流流的通过率（伪随机性）。用FIPS 140-2和广义FIPS 140-2伪随机性测试规范分别评估了4个PRNG产生的1000条100 000比特长的密钥流和1000条1 000 000比特长的密钥流和改进的密钥流的通过率。结果表明，本文的方法能够显著提高四个PRNGs生成的密钥流的伪随机性。m序列伪随机数发生器生成的长度小于100 000比特的密钥流的伪随机性能不佳。
分类： 物理学 >> 核物理学 提交时间： 2025-04-22
Xu, Dr. Shoulong
Li, Mr. Qinxin
Wei, Miss Cuiyue
WANG, Mr. YuBo
Wang, Mr. Zhi ling
Huang, Dr. You-Jun
Wei, Dr. Qingyang
ZOU, Prof. Shu-liang
摘要： This paper conducts research on β -ray detection methods based on complementary metal-oxy-semiconductor (CMOS) active pixel sensors (APS), analyzes the mechanism and characteristics of β -radiation response and damage, discusses the nonlinear influence characteristics of annealing effect on sensor damage, and proposes a gain optimization method based on double-threshold constraints and develops a noise suppression technique utilizing temporal differences. Additionally, it establishes a β-ray detection model correlating visual imaging with radiation absorption dose. Through 63Ni β radioactive source irradiation experiments and Geant4 Monte Carlo simulations, the characteristics of β -ray radiation response events of CMOS APS at different gains, the average pixel values of dark images at different integration times, energy deposition, damage modes and room-temperature annealing effects are studied. The experimental results show that the β -radiation response event is characterized by the near-saturation of the pixel value of a single pixel and affects the sharp increase of the pixel values of a very small number of surrounding pixels. The optimal gain for β -ray measurement was obtained as 43dB through the double-threshold constraint gain optimization method. When it is lower than 43dB, the sensor does not amplify the charge signal generated by β -rays sufficiently, and the effective signal intensity is weak. When the gain is higher than 43dB, the response signal is distorted due to charge overflow. With the increase of irradiation time, the damage of CMOS APS keeps intensifying. The room-temperature annealing effect leads to a nonlinear change in its damage trend. During the annealing process, the reduction in the number of dark signals is partly due to the sensor's self-recovery to the pedestal noise level, and partly because of the intermittent failure of the pixels, temporarily losing the charge collection ability, manifested as a pixel value of 0. The temporal difference filtering method can well remove noise and effectively retain β response events. Its retention rate reaches 99.75%, the signal-to-noise ratio has increased by 5.17 times compared with that before noise reduction. When the sensor is in the low-integration time region below 5.625ms, the matching degree between the calculated energy deposition and the simulated energy deposition is relatively high. However, in the high-integration time region above 5.625ms, the charge saturation effect occurs in the sensor pixels, the error increases significantly. The gray value - dose detection model based on piecewise exponential attenuation correction can achieve the quantification of the absorbed dose of β -rays.
分类： 核科学技术 >> 核材料与工艺技术 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要： Three kinds of amphiphilic PMADAB gels were prepared through radiation-induced polymerization and crosslinking of methacryloxyethyl dimethylalkane ammonium bromide (MADAB) with different alkyl side chains (butyl, octyl and dodecyl). The length of alkyl side chains had significant influence on swelling behavior of the PMADAB gels in alcohol/water solvent. Equilibrium swelling degree (EDS) of PMBDAB (butyl) gel in water was ca. 160 and decreased with increasing alcohol content (x), whereas EDS of PMODAB (octyl) and PMDDDAB (dodecyl) gels showed a convex-upward function of x, i.e., these two gels barely swelled in pure water and swelled with increasing x and then shrank gradually. This phenomenon was explained by the hydrophobic association of long alkyl chains and a cosolvency effect of PMADAB in alcohol and water. The swelling behavior of PMADAB gels in methanol, ethanol and isopropanol were similar, and their EDS are related with the dielectric constant of alcohol solvents. The results suggest that PMADAB gels may be potential absorbents for various kinds of alcohols.
分类： 物理学 >> 凝聚态:结构、力学和热性能 提交时间： 2017-03-26
摘要： The vacancy-type defects induced by co-implantation of He and H ions in China Low Activation Martensitic (CLAM) steel at room temperature were investigated with a variable-energy position beam Doppler broadening spectra (DBS). The co- implantation contained two patterns: one was implanted by He ions firstly, and then followed by H-ions implantation; the other was implanted by H ions in the first place, after that followed by He-ions implantation. The S parameters of implanted samples became larger than un-implanted one under different implantation fluences, and the S parameters of pre-implanted H were larger than pre-implanted He regardless of fluence. The difference of S parameters between pre-implanted H and He decreased with increasing fluence. He-H-vacancy complex is the reason that the S parameter of pre-implanted H is higher than pre-implanted He
分类： 核科学技术 >> 核材料与工艺技术 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要： Poor mechanical properties of PNIPAAm hydrogels have limited their applications. Nanocomposite hydrogels (NC gels) which incorporate inorganic clay possess high mechanical strength and other desirable properties. In this paper, we report a facile approach to synthesize NC gels using radiation technique. With exfoliated clay sheets acting as crosslinkers, N-isopropylacrylamide monomers are polymerized and crosslinked to form NC gels under -irradiation at room temperature. Apart from regular swelling behavior and interesting performance in thermo sensitivity, the radiation synthesized NC gel (RNC gel) has good optical transparency, high strength and flexibility. Through Micro-FTIR, XPS and TG analyses, a particular chemically crosslinked organic/inorganic network was identified in the RNC gel.
分类： 材料科学 >> 材料科学（综合） 提交时间： 2023-12-05
Wang Hongyang
Wu Hao
Wu Zhixing
Geng Zhihui
Zhou Juncheng
Deng Ziqi
Yan Liqin
Qian Peng
Ye Shufeng
Shi Ke
Chen Ning
摘要： This study synthesized copper-substituted lead apatite using the hydrothermal method, starting from hydroxyapatite precursors. For stability, it is recommended to maintain copper substitution below x=2 in the Pb10-xCux(PO4)O apatite. The introduction of copper appropriately reduces the lattice constant, in line with DFT theoretical calculations. Non-equilibrium heat treatment introduces additional charge carriers; oxygen-rich tempering shifts the sample to paramagnetism, while anaerobic tempering leads to complex and unique hysteresis loops. Non-equilibrium annealing can increase carrier concentration, but its efficacy is limited. Although some improvements have been observed, further exploration involving additional element doping or seeking interfaces with suitable conductive phases is needed to achieve superconductivity.
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