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关键词： 可调谐二极管激光吸收光谱   二次谐波   波形恢复   调节因子  

摘要： 针对微弱气体吸收光谱线的二次谐波信号检测过程中存在的噪声干扰问题,提出利用频率分解(FD)和Savitzky-Golay滤波(SG滤波)相结合方法(简记为FD-SG滤波)对含噪信号进行降噪。频率分解是一种用于分解复杂信号的数学方法,其优点是能够自主选择分解个数或者采用非递归方式求解。SG滤波能够对成组的数据进行处理,在维持信号变化趋势和宽度的同时提高数据的精准度。首先对含噪信号进行频率分解,再进行SG滤波二次降噪处理,最后将滤波后的有效层分量进行重构,得到降噪后的二次谐波信号。讨论分析了频率分解后各层分量的分布情况,验证有效信号主要分布在第一层分量内,并且仍会含有残余噪声;通过构建调节因子P选取最优的SG滤波框长,使得有效层残留噪声得到有效去除。针对空气中的CO_(2),采用1578.222 nm的吸收光谱线进行实验,结果显示二次谐波信号中存在大量噪声,尤其在扫描周期交界处出现大尖峰噪声。通过拟合曲线扣除处理和频率分解,发现大尖峰噪声未明显减弱。随后结合SG滤波处理并比较了二次谐波与大尖峰峰值的关系,结果表明SG滤波能够有效减弱大尖峰噪声,选择合适滤波框长即可得到较为理想的降噪效果。在对人体呼出CO_(2)的二次谐波信号进行检测时,发现吹气引起的湍流导致信号幅值增大并抖动,通过FD-SG滤波处理成功抑制了噪声,恢复出较为平滑的二次谐波信号。验证了该算法对实际微弱气体检测的二次谐波信号降噪的性能,在实现噪声抑制及大尖峰结构噪声的减弱方面表现出较突出的优势。这对微弱气体检测方面提高信号质量和系统精度有积极意义。

关键词： 计量学   辐射源   检定规程  

摘要： 文章介绍了JG1028—2024《放射治疗模拟定位X射线辐射源》的修订背景、修订的主要内容、规程实施过程中的注意事项等,旨在指导计量检定人员正确理解并规范执行该规程。

关键词： 科技变革   原子弹   社会结构   熊培云  

摘要： 2024年熊培云出版《人的消逝:从原子弹、互联网到人工智能》(以下简称《人的消逝》)一书。读者发现爱热闹的熊培云回来了,他同样关注时下最热的科技变革。技术正在重塑社会的结构,成为反思时代问题的重要切面。当机器在很多方面都已经做得比人类更好,人类与科技最好的关系是什么?科技至上还是文化至上?我们就相关问题与熊培云进行了一番笔谈。

关键词： 作战经验   导弹巡洋舰   原子弹   核武器   海军  

摘要： 第二次世界大战结束时,美国海军是世界上规模最大、装备最先进和作战经验最丰富的海军力量。但随着战争结束,这支大规模常规海军面临转型。1949年和1953年苏联相继试爆原子弹和氢弹成功,在核武器方面美国已不再是一家独大。

关键词： 宽禁带   半导体   X射线探测器   碳化硅   氮化镓   金刚石  

摘要： 高性能半导体X射线探测器应具备低检测限、低暗电流、高灵敏度、快速响应、强抗辐照性能等特点。碳化硅、氮化镓、金刚石、氧化镓和氧化锌等宽禁带半导体因具有宽禁带宽度、高电子迁移率、高击穿场强、高饱和载流子漂移速度、大离位能等特性,在X射线探测中展现出优异性能,符合高性能半导体X射线探测器的特点要求,成为极具前景的X射线探测器。本文介绍了碳化硅、氮化镓、金刚石、氧化镓和氧化锌等宽禁带半导体材料特性、制备技术和X射线探测器研究的最新进展,为医学成像、工业检测和太空探索等未来研究方向和潜在应用提供了参考。

关键词： 计算机断层扫描   X射线   CT  

摘要： 在现代医学的浩瀚星空中,CT(计算机断层扫描)技术以非凡的透视能力,为医生们打开了一扇洞察人体奥秘的大门。CT技术的基础是什么CT技术的诞生源自科学家对精准医疗影像的不懈追求。CT技术的核心是X射线与计算机技术的完美结合。它利用X射线对人体进行多层面、多角度的扫描,每经过一层,X射线都会穿透人体并被探测器接收。这些接收到的数据就像是拼图的一块块碎片,经过计算机的高速运算和图像重建算法,最终被编织成一幅幅清晰的人体内部结构图像。

关键词： Transient absorption spectroscopy  

摘要： Organic solar cells involve processes such as the generation, separation, and transmission of photogenerated charges, which directly affect their efficiency and stability. Femtosecond transient absorption spectroscopy (fs-TAS) is an effective technique for understanding the dynamics of photogenerated electron transfer. By measuring the response to femtosecond laser pulses, fs-TAS provides deep insights into the photoexcitation and energy transfer mechanisms in optoelectronic materials, helping optimize material performance. This review summarizes research on femtosecond timeresolved absorption spectroscopy in organic solar cells and contributes to the understanding of this research field both domestically and internationally. It comprehensively introduces the working principles, hardware equipment, and data processing of fs-TAS and two-dimensional electronic spectroscopy, followed by discussing their application progress in the photogenerated charge dynamics process of organic solar cells. Finally, future developments in organic solar cells are discussed. © 2025 Universitat zu Koln. All rights reserved.

关键词： Qubits  

摘要： Objective Due to long coherence time and exceptional controllabilhy, trapped-ion Systems have become a fundamental experimental platform for frontier research fields, including large-scale quantum Computing, high-precision atomic clocks, and weak force measurements. Among the various ions suilable for experimental research, 1/1Yb+ has gained significant attention in recent years düe to its nonzero nuclear spin and complex electronic structure of the excited states, which give rise to a rieh energy level spectrum. A detailed investigation of its level structure deepens the understanding of its transition mechanisms. In particular, its long-lived metastable states serve as ideal reference for clock transitions and enable qubit encoding. The electric quadrupole (E2) transition between the ground and metastable states is more complex than electric dipole transitions, as it is influenced by the polarization and external magnetic field geometry. Consequently, a comprehensive study of E2 transitions in 1/1Yb+ not only provides crucial experimental guidance for optimizing energy-level selection and transition efficiency in high-precision optical clocks but also expands precision measurement techniques based on quadrupole transitions. These techniques can be applied to probing potential variations in fundamental physical constants in fundamental physics. Moreover, the long-lived metastable states and multi-level structure of 1/1Yb+ hold significant potential for quantum information processing. In contrast to Standard qubit encoding that relies on two-level Systems, utilizing the metastable states allows for qudit encoding, thereby enhancing storage capacity and computational efficiency in quantum Computing. Additionally, the dependence of E2 transitions on light field polarization can be exploited to engineer highly controllable photon-atom interactions, which enables the Simulation of topological phases and non-Hermitian quantum Systems. Methods We investigate the E2 transi

关键词： Photointerpretation  

摘要： Aiming at the existing high grayscale image enhancement algorithms with poor robustness and insufficient adaptive capability, an enhancement algorithm capable of adaptively enhancing the processed high-bit images was proposed. To compensate for the brightness and darkness of the original film, an adaptive correction algorithm based on the grayscale prior was designed, and a new high-level HSV pseudo-color enhancement algorithm was presented. In addition, to ensure the balance of the enhanced image, an adaptive balance processing algorithm based on the brightness Channel was proposed. Finally, the enhancement effect was performed on the 12-bit X-ray negative image generated in the industrial welding manufacturing field. The experimental results showed that the proposed method could achieve the best enhancement effect on many different test samples without significantly increasing the complexity of the algorithm. © 2025 CIMS. All rights reserved.

关键词： Frequency   Status   X-ray diagnosis  

摘要： Objective To investigate the current status of diagnostic X-ray resources in Jinan in order to provide theoretical basis for continuously optimizing the allocation of diagnostic resources and strengthening the management of radiological health and radiation protection. Methods In accordance with the 2023 Jinan radiation protection monitoring program of medical and health institutions, a survey was carried out for medical institutions involved in diagnostic X-ray examinations (excluding military hospitals and dental clinics) in Jinan by using uniform questionnaires. The survey included the basic situation of diagnostic X-ray institutions, the allocation of diagnostic X-ray equipment, the number of diagnostic staff, and the frequency of diagnositic X-ray examinations. Results In 2023, there were 298 diagnostic X-ray institutions in Jinan, with 3 494 diagnostic workers and 1 387 items of diagnostic X-ray equipment. The included were 41 tertiary hospitals, 57 secondary hospitals, 110 primary hospitals and 90 unrated hospitals. The tertiary hospitals possessed the largest number of the diagnostic workers and equipment, accounting for 60.99% and 45.35% of the total, respectively. Among all the items of diagnostic X-ray equipment, the number of items of digital radiography equipment ranked top (34.37%), followed by CT machines (24.44%). There were 147.32 items of diagnostic X-ray equipment per million population on average. A total of 8 180 363 individuals received various types of diagnostic X-ray examinations, with CT diagnosis accounting for 46.93% and X-ray for 34.41%. The frequency of diagnostic X-ray examinations was 868.86/1 000 population, including the frequency of CT examinations of 407.76 per 1 000 population. Conclusions The per capita possession of medical X-ray equipment in Jinan is at a high level. The frequency of medical exposure has increased significantly, especially CT examinations. There is a big gap in diagnostic X-ray resource allocation between diff