分类： 农、林、牧、渔 >> 农、林、牧、渔业科学其他学科 提交时间： 2024-06-26 合作期刊: 《农业图书情报学报》
摘要： 目的/ 意义 探究大语言模型渊Large Language Models，LLMs冤等人工智能生成技术对用户信息检索行为产成的 影响，为信息检索系统和信息资源建设建言献策。 方法/ 过程 以ChatGPT 等LLMs 的蓬勃发展为背景，结合大语言模型的技 术特点与现有产品的特征，从用户信息行为的视角，通过探讨现有文献和大型语言模型，分析该技术的不断普及对信息检索 系统与用户检索行为的影响。 结果/ 结论 LLMs 用作信息检索系统具有传统产品无法比拟的优势，其对用户信息检索行为的 底层逻辑、行动重点与检索期望等方面都会产成影响。然而LLMs 现有可靠性、准确度等缺陷仍难以使其立刻取代传统信息检 索方式。建议在信息检索系统和信息资源建设中重视该技术，探索LLMs 与信息服务智能结合，以应对未来用户信息需求的变 化，并进一步充分利用已有信息资源的价值。
分类： 农、林、牧、渔 >> 农、林、牧、渔业科学其他学科 提交时间： 2024-06-26 合作期刊: 《农业图书情报学报》
摘要： 目的/ 意义 进入到大数据推荐时代，图书馆的信息呈现渠道从线下实体转向线上数字化，在此过程中科学数据的 使用频次呈现出指数级增长。本研究旨在分析科学数据的知识产权的服务保障影响数字图书馆发展的内在机理。 方法/ 过 程 以问卷调查法为基础，对高知群体进行问卷调查。采用问卷调查法调研获得样本252 份有效样本，并利用验证性因子进行 分析检验，发现问卷各因子信度介于0.724~0.913 之间，问卷通过验证性因子分析检验证明具备较好效度。 结果/ 结论 政 策法规落实效率、人才队伍建设、数据管理技术、服务模式多样化、数据产权共享协议数量5 类因素均会显著正向影响科学 数据知识产权服务，基于此为图书馆在科学数据知识产权服务领域提出5 项优化策略。
分类： 核科学技术 >> 核科学与技术 提交时间： 2024-06-20
摘要： 近年来我国能源清洁化率不断提高，以风电和光伏为代表的规模化新能源出力存在明显的波动性和不确定性，另一方面，电网的负荷需求、增长和总量达不到预期，这对电网的调峰能力提出了新的考验和挑战，为确保厂网安全，核电机组参与调峰越来越频繁,这对核电机组的核安全又带来了新的挑战，甚至可能会影响中国核电事业的长远发展。本文对核电机组参与电网调峰可能给电厂安全及系统设备造成的影响进行了分析，重点分析了参与电网调峰对电厂安全性、可靠性、经济性以及对三废处理的影响，并提出了合理化建议和改进方向，为我国核电机组的运行和参与调峰提供了示范思路。
分类： 农、林、牧、渔 >> 农、林、牧、渔业科学其他学科 提交时间： 2024-06-26 合作期刊: 《农业图书情报学报》
摘要： 目的/ 意义 面向学生视角对高校图书馆服务进行科学的衡量与评价是明晰图书馆提升价值影响关键路径的重要方 式，有助于图书馆自身优化服务，完善发展框架，提升自身价值。 过程/ 方法 研究通过结构方程模型分析方法对获得的 985 份有效调研数据进行分析，构建了以“情境- 作用- 成效”为主线的面向学生视角的高校图书馆价值影响模型，挖掘了 关键的影响因素。 结果/ 结论 建议高校图书馆在以下4 个方面提升价值影响：增强政策引领提升高校图书馆服务使用率； 重视高校图书馆在服务“双一流”建设中的贡献与价值；研究并构建与用户需求相契合的服务体系；增强对高校“双一流” 的服务支持。
分类： 护理学 >> 护理学 提交时间： 2024-06-26
摘要： 本文总结1例应用银翘三黄膏调制金黄散外敷治疗亚急性甲状腺炎的护理体会。通过开展科学护理评估，掌握患者甲状腺疼痛、及肿大程度，辩证后给予银翘三黄膏调制金黄散外敷治疗，通过10天治疗患者疼痛及甲状腺肿大症状明显改善。
分类： 护理学 >> 护理学 提交时间： 2024-06-26
摘要： 本文总结1例帕金森病高热综合征患者运用中医传统疗法联合常规治疗的护理体会。通过开展护理评估，在常规护理基础之上，实施刺络放血、穴位按摩、穴位贴敷、八髎压灸、康复导引术的中医传统疗法，有效的提高了治疗效率，使帕金森病高热综合征患者的症状得到了明显的改善。
分类： 计算机科学 >> 计算机科学技术其他学科 分类： 生物学 >> 分子生物学 分类： 数学 >> 逻辑 提交时间： 2024-06-26
摘要： Polymer aggregates and molecular polymers are written as computable numbers, realizing the unity of cells and universal Turing machines with the Entscheidungsproblem. However, whether the Entscheidungsproblem of cells really exists remains elusive. Alan Turing found universal Turing machines read only computable numbers written by humans who further differentiate transcendental numbers from the set of computable numbers by Georg Cantor’s diagonal process. It follows that the decidability of the Entscheidungsproblem derived from humans eliminates the independence of computable numbers from each other and enables computable numbers to be fused with each other into the set of computable numbers, with the result that humans are endowed with a capacity to read of the fusion of computable numbers with each other into the set of computable numbers by humans to read the set of computable numbers by being endowed with a capacity to write computable numbers. Accordingly, it is shown here how humans write cell backbones as complex numbers read by artificial intelligence machines emulated by cells by writing polyribonucleotides as computable numbers read by universal Turing machines emulated by extracellular ribosomes to extend Georg Cantor’s continuum hypothesis by extending Alan Turing’s work on the Entscheidungsproblem, realizing the unity of humans, cells, and artificial intelligence machines without the Entscheidungsproblem.
提交时间： 2024-06-26
摘要： 本研究综述了体育锻炼对改善大学生特质焦虑的影响。大学生作为心理健康问题的高发群体，面对学业和社会的多重压力，常常表现出较高水平的特质焦虑。通过分析大量相关文献，我们发现适度的体育活动对降低焦虑水平、提高心理健康状况具有显著的积极作用。不同类型的体育活动在缓解焦虑方面的效果有所不同，研究表明有氧运动、团队运动以及一些特定项目均能有效缓解特质焦虑。然而，目前的研究多采用自评量表评估焦虑，存在主观偏差，且不同体育项目的具体影响机制尚需进一步探讨。未来研究应着重细化不同类型体育活动的具体影响机制，探索个性化的体育干预方案，并通过长时间的纵向研究验证其长期效果。高校应积极推广体育锻炼，营造健康的校园环境，帮助大学生更好地应对心理压力，实现身心全面发展。
分类： 核科学技术 >> 核科学与技术 提交时间： 2024-06-21
摘要： 氦氙冷却反应堆以氦氙混合气体作为布雷顿循环运行工质，具有循环效率高、功率质量比高和运行可靠等特点，在深空大功率核反应堆电源和无人潜航器核动力等领域具有广阔的应用前景。针对氦氙布雷顿循环系统运行特性，本文建立了涡轮机、压缩机、紧凑型换热器等氦氙布雷顿循环热力设备仿真模型，开发了氦氙冷却反应堆布雷顿循环运行性能分析仿真工具。以“普罗米修斯”氦氙冷却反应堆布雷顿循环系统为研究对象，分析循环各点参数与各部件性能对系统效率和系统比功的影响。结果表明：系统效率与系统比功均存在最佳压比，循环最高温度越高、最低温度越低，系统效率与系统比功越大；压力对循环的影响不明显，压力越大，系统效率与系统比功略微减小；回热器总热导率越大，系统效率越大，系统比功不变。
分类： 核科学技术 >> 核动力工程技术 提交时间： 2024-06-23
摘要： 为了进一步提高球床式高温气冷堆堆芯物理计算精度，西安交通大学核工程计算物理（Nuclear Engineering Computational Physics, NECP）实验室自主研发了适用于球床式高温气冷堆物理热工计算程序NECP-Panda的中子学计算模块。本文介绍了NECP-Panda的计算框架，重点阐述了中子学计算部分的理论方法并进行了验证计算。计算问题包括简化混合球床堆算例以及高温气冷堆核电示范工程（High Temperature Reactor Pebble-bed Module, HTR-PM）的净堆装料和吸收体价值计算。数值结果表明，NECP-Panda对简化混合球床堆的keff计算与蒙特卡罗连续能量结果符合良好，计算的HTR-PM临界装料高度与蒙特卡罗连续能量结果高度一致，吸收体价值非常吻合，证明了NECP-Panda针对球床式高温气冷堆的中子学计算具有良好的计算能力和精度，为后续模块的开发奠定了坚实基础。
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： Polarization vectors of light traveling in a coiled optical fiber rotate around its propagating axis even in the absence of birefringence. This rotation was usually explained due to the Pancharatnam-Berry phase of spin-1 photons. Here, we use a purely geometric method to understand this rotation. We show that similar geometric rotations also exist for twisted light carrying orbital angular momentum (OAM). The corresponding geometric phase can be applied in photonic OAM-state-based quantum computation and quantum sensing.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： How migratory birds can find the right way in navigating over thousand miles is an intriguing question, which much interested researchers in both fields of biology and physics for centuries. There several putative proposals that sound intuitively plausible all remain contested so far because those hypothesis-models of magnetoreceptor to sense geomagnetic field need either extremely high sensitivity or humankind-like intelligence to guide. Here we explore theoretically that the birds can navigate to their destination through an entirely new scenario to sense the geomagnetic field. Our proposal is based on separate peaks of the resonance-fluorescence spectrum of a four-level system derived from the ferric sulfide cluster which exists in a protein complex (Drosophila CG8198) of migratory birds. As the separation of spectral peaks contains information about geomagnetic field at both current location and birthland, the change of such separation cues the bird to choose a right direction to move and double-resonance emerges once arrived the destination. Our theoretical mechanism can explain previous experiments on the disorientation of migratory birds caused by oscillating magnetic field naturally and more precisely. This work provides insight to explain migratory navigation and motivates possible manmade practical devices.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： Conventional coherent absorption occurs only when two incident beams exhibit mirror symmetry with respect to the absorbing surface, i.e., the two beams have the same incident angles, phases, and amplitudes. In this work, we propose a more general metasurface paradigm for coherent perfect absorption, with impinging waves from arbitrary asymmetric directions. By exploiting excitation of unidirectional evanescent waves, the output can be fixed at one reflection direction for any amplitude and phase of the control wave. We show theoretically and confirm experimentally that the relative amplitude of the reflected wave can be tuned continuously from zero to unity by changing the phase difference between the two beams, i.e. switching from coherent perfect absorption to full reflection. We hope that this work will open up promising possibilities for wave manipulation via evanescent waves engineering with applications in optical switches, one-side sensing, and radar cross section control.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： We show that the time-averaged Poynting vector in parity-time (PT ) symmetric coupled waveguides is always positive and cannot explain the stopped light at exceptional points (EPs). In order to solve this paradox, we must accept the fact that the fields E and H and the Poynting vector in non-Hermitian systems are in general complex. Based on the original definition of the instantaneous Poynting vector, a formula on the group velocity is proposed, which agrees perfectly well with that calculated directly from the dispersion curves. It explains not only the stopped light at EPs, but also the fast-light effect near it. This investigation bridges a gap between the classic electrodynamics and the non-Hermitian physics, and highlights the novelty of non-Hermitian optics.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： Traditional lasers function using resonant cavities, in which the round-trip optical path is exactly equal to an integer multiple of the intracavity wavelengths to constructively enhance the spontaneous emission rate. By taking advantage of the enhancement from the resonant cavity, the narrowest sub-10-mHz-linewidth laser and a $10^{-16}$-fractional-frequency-stability superradiant active optical clock (AOC) have been achieved. However, a laser with atomic spontaneous radiation being destructively inhibited in an anti-resonant cavity, where the atomic resonance is exactly between two adjacent cavity resonances, has not been reported. Herein, we experimentally demonstrate inhibited stimulated emission and termed it an inhibited laser. Compared with traditional superradiant AOCs, which exhibit superiority in terms of the high suppression of cavity noise, the suppression of the cavity-pulling effect of an inhibited laser can be further improved by a factor of $(2F/pi)^2$, i.e., 2.07 in this work, which was improved from 26 to 53 times. This study will guide further development of AOCs with better stability, and thus, it is significant for quantum metrology and may lead to new research in the laser physics and cavity quantum electrodynamics fields.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： Resampling by interpolation is the traditional method to process sample in nonunform sampling Fourier transform spectrometer. Nonuniform discrete Fourier transform is an alternative to interpolation that has not been overlooked before. With the aid of experiment, we systematically compare the NUFFT method with resampling by interpolation FFT method in nonuniform sampling Fourier transform spectrometer. We found that NUFFT is comparable to interpolation in spectral profile and spectral noise levels and is better in spectral amplitudes. We also found that It has significant advantage in under-sampling and anti-aliasing property which is offered by the unique non-periodic nature of nonuniform sampling. It is faster and consumes less computer memory in our python implementation. Overall, we found that NUFFT is superior to traditional interpolation method with mostly better performances as well as additional capabilities.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
Xiao Sun
Song Liang
Weiqing Cheng
Shengwei Ye
Yiming Sun
Yongguang Huang
Ruikang Zhang
Jichuan Xiong
Xuefeng Liu
John H. Marsh
Lianping Hou
摘要： We report an AlGaInAs multiple quantum well integrated source of polarization controlled light consisting of a polarization mode converter PMC, differential phase shifter(DPS), and a side wall grating distributed-feedback DFB laser. We demonstrate an asymmetrical stepped-height ridge waveguide PMC to realize TE to TM polarization conversion and a symmetrical straight waveguide DPS to enable polarization rotation from approximately counterclockwise circular polarization to linear polarization. Based on the identical epitaxial layer scheme, all of the PMC, DPS, and DFB laser can be integrated monolithically using only a single step of metalorganic vapor phase epitaxy and two steps of III V material dry etching. For the DFB-PMC device, a high TE to TM polarization conversion efficiency 98% over a wide range of DFB injection currents is reported at 1555 nm wavelength. For the DFB-PMC-DPS device, a 60 degree rotation of the Stokes vector was obtained on the Poincar\'e sphere with a range of bias voltage from 0 V to -4.0 V at IDFB is 170 mA.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： Light-matter coupling strength and optical loss are two key physical quantities in cavity quantum electrodynamics (cQED), and their interplay determines whether light-matter hybrid states can be formed or not in chemical systems. In this study, by using macroscopic quantum electrodynamics (mQED) combined with a pseudomode approach, we present a simple but accurate method which allows us to quickly estimate the light-matter coupling strength and optical loss without free parameters. Moreover, for a molecular emitter coupled with photonic modes (including cavity modes and plasmon polartion modes), we analytically and numerically prove that the dynamics derived from the mQED-based wavefunction approach is mathematically equivalent to the dynamics governed by the cQED-based Lindblad master equation when the Purcell factor behaves like Lorentzians.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： One of the fundamental challenges in nanophotonics is to gain full control over nanoscale optical elements. The precise spatiotemporal arrangement determines their interactions and collective behavior. To this end, DNA nanotechnology is employed as an unprecedented tool to create nanophotonic devices with excellent spatial addressability and temporal programmability. However, most of the current DNA-assembled nanophotonic devices can only reconfigure among random or very few defined states. Here, we demonstrate a DNA-assembled rotary plasmonic nanoclock. In this system, a rotor gold nanorod can carry out directional and reversible 360 degree rotation with respect to a stator gold nanorod, transitioning among 16 well-defined configurations powered by DNA fuels. The full-turn rotation process is monitored by optical spectroscopy in real time. We further demonstrate autonomous rotation of the plasmonic nanoclock powered by DNAzyme-RNA interactions. Such assembly approaches pave a viable route towards advanced nanophotonic systems entirely from the bottom-up.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： We study the geometric response of three-dimensional non-Hermitian crystalline systems with nontrivial point-gap topology. For systems with fourfold rotation symmetry, we show that in the presence of disclination lines with a total Frank angle which is an integer multiple of $2\pi$, there can be nontrivial one-dimensional point-gap topology along the direction of the disclination lines. This results in disclination-induced non-Hermitian skin effects. By doubling a non-Hermitian Hamiltonian to a Hermitian three-dimensional chiral topological insulator, we show that the disclination-induced skin modes are zero modes of the effective surface Dirac fermion(s) in the presence of a pseudomagnetic flux induced by disclinations. Furthermore, we find that our results have a field theoretic description, and the corresponding geometric response actions (e.g., the Euclidean Wen-Zee action) enrich the topological field theory of non-Hermitian systems.
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