分类： 图书馆学、情报学 >> 情报学 提交时间： 2024-04-16
摘要： 数字经济时代最特殊的一种资产就是数据，数据作为生产要素和企业资产，已成为新时代我国的生产核心要素，是数字经济的核心引擎，数据要素不仅推动传统生产要素革命性聚变与裂变进而产生倍增效应，而且提高了传统要素的配置效率，驱动经济加快创新发展。然而数据流通交易作为数据要素市场化配置的关键环节却缺乏有效实践，本文从信息管理的角度出发，以上海数据交易所为例，从制度保障、基础设施建设以及平台运营机制这三个方面为企业数据资产化的实现路径提供一个样本参考，通过这一研究，旨在提高企业更加重视数据要素的意识，重视数据资产的价值挖掘和使用，致力于有效实现资源统筹优化，从而有效推动我国经济高质量发展。
分类： 图书馆学、情报学 >> 读者工作 提交时间： 2024-04-16
摘要： 本文探讨近年来国内外图书馆读者荐购的研究热点并分析现有读者荐购服务的痛点和挑战，并对未来荐购管理模式创新和荐购系统建设提出设想，以期提高图书馆读者荐购服务质量，推动传统图书馆服务向智慧化转型。采用文献计量法，对国内外图书馆读者荐购相关研究进行梳理，分析了国内外读荐购的最新研究成果并对发文主体进行概述分析。采用SWOT法对读者荐购进行分析，探讨现行荐购管理模式的优缺点。研究发现，传统的荐购模式已不能完全适应智慧图书馆建设的要求。图书馆应着力利用资源优势围绕用户需求搭建智能化、个性化荐购平台，将信息技术运用于读者荐购服务场景中。
分类： 图书馆学、情报学 >> 图书馆学 提交时间： 2024-04-16
摘要： 目的/意义］为促进数智时代交易场所强化合规管理，打造安全可信流通环境，围绕数据交易平台经营者的安全保障义务进行制度设计尤为重要。［方法/过程］数据交易平台作为新型经营场所，其经营者的安全保障义务的正当性可由获利报偿理论、控制力理论与信赖保护等理论得以证成。［结果/结论］从传统经营场所、电子商务平台到数据交易平台，由于经营者的风险控制力等因素差异，三者呈现出安全保障义务与民事责任水平递增的类型序列。数据交易平台经营者的安全保障义务的内容应包括资质资格审核、提供安全可靠的交易环境、记录交易痕迹等交易前、中、后义务。在有其他侵权人介入时，对数据交易平台责任形态的认定应通过部分连带责任进行规范续造，以合理确定数据交易平台经营者的民事责任。
分类： 生物学 >> 植物学 >> 应用植物学 提交时间： 2024-04-17 合作期刊: 《广西植物》
摘要： 为探讨外源多胺（PAs）对荔枝胚性愈伤组织（EC）增殖及体胚分化的影响机制， 该研究以“妃子笑”荔枝EC 为材料，采用单因素法在增殖培养基中添加腐胺（Put）、亚 精胺（Spd）及精胺（Spm），分析了不同PAs 处理后EC 形态、结构、内源PAs 含量及相 关酶指标的变化。结果表明：（1）外源Put、Spd 和Spm 处理均显著提高了EC 增殖率，降 低了体胚诱导及萌发数量。经外源PAs 处理增殖的EC 胚性细胞大小较一致，染色深且均匀， 多细胞原胚减少，可见已经分化完全的早期子叶胚。（2）外源PAs 处理均显著提高了EC 中内源PAs 含量，其中Put 处理EC 中各类内源PAs 及总PAs 含量最高；当在含外源PAs 培养基上增殖的EC 转入不含外源PAs 的培养基上增殖时（恢复培养），EC 中的Put 含量 仍然显著高于对照，内源Spd 和Spm 则显著降低。（3）外源Put 处理显著提高了EC 中的 鸟氨酸脱羧酶（ODC）、精氨酸脱羧酶（ADC）和二胺氧化酶（DAO）活性，而外源Spd、 Spm 处理显著降低了EC 中的ODC 及ADC 活性，外源Spd 显著提高了多胺氧化酶（PAO） 活性；恢复培养后，EC 中ADC 和DAO 活性比恢复培养前显著降低，ODC、PAO 无显著 性差异。综上认为，外源PAs 可以通过调节PAs 代谢相关酶活性影响内源PAs 含量，进而 影响荔枝EC 增殖和体胚诱导。该研究结果为进一步研究PAs 调节荔枝体胚发生机制，提高 荔枝离体再生效率提供了基础。
分类： 生物学 >> 植物学 >> 应用植物学 提交时间： 2024-04-17 合作期刊: 《广西植物》
摘要： 膨胀素（expansin，EXP）通过调控细胞壁的松弛在植物应对环境胁迫过程中起着 重要作用。为研究EXP 基因在大豆应对非生物胁迫过程中的作用，对大豆中的两个EXP 基 因（GmEXPB5 和GmEXPB7）及其蛋白序列进行生物信息学分析，通过实时荧光定量PCR （qRT-PCR）检测基因表达量。结果表明：(1) GmEXPB5 和GmEXPB7 分别位于大豆第10 和12 号染色体上，编码的蛋白序列长度分别为272 和267 个氨基酸。GmEXPB5 蛋白分子 量为29.07 kD，理论等电点为7.51；GmEXPB7 蛋白分子量为29.09 kD，理论等电点为8.66。 GmEXPB5 和GmEXPB7 均为稳定的亲水蛋白且定位于细胞壁中。GmEXPB5 和GmEXPB7 蛋白均含有一段信号肽序列和一个保守的DPBB_1 结构域。(2) GmEXPB5 蛋白与鹰嘴豆 CaEXPB15 蛋白亲缘关系最近，GmEXPB7 蛋白与密花豆、赤豆和豇豆的EXPB3 蛋白有着 较近的亲缘关系。(3) GmEXPB5 和GmEXPB7 在大豆根、茎和叶中均表达且它们在根和叶中 的表达量均显著高于茎中的表达量。(4) GmEXPB5 和GmEXPB7 在大豆幼苗中可以响应盐、 干旱和低温胁迫。(5) GmEXPB5 启动子区域含有两种与逆境相关的顺式作用元件（ABRE 和 ARE）；GmEXPB7 启动子区域含有五种与逆境相关的顺式作用元件（ABRE、ARE、 CGTCA-motif、TC-rich repeats 和MBS）。上述结果表明，GmEXPB5 和GmEXPB7 能够参 与大豆对非生物胁迫的应答。
分类： 生物学 >> 植物学 >> 应用植物学 提交时间： 2024-04-17 合作期刊: 《广西植物》
摘要： 为研究和明确贵州兔眼蓝莓不同品种的果实香气成分及含量，该研究采用顶空固相 微萃取和气相色谱-气质联用（HS-SPME/GC-MS）方法，对贵州主栽兔眼蓝莓‘杰兔’‘灿烂’ ‘顶峰’‘梯芙蓝’和‘粉蓝’等品种的果实香气组分含量进行检测分析。结果表明：（1）5 个品种共检测出7 大类46 种香气成分，其中醇类有8 种、萜类有13 种、苯环类有9 个、醛 类仅3 种、酯类5 种、烷烃类有4 种、其他类有4 种。（2）‘顶峰’的香气成分最多，有33 种，‘粉蓝’最少，仅24 种；各品种香气组分中，醛类占比最大，其次为苯环类，‘灿烂’醛 类含量最高（59.32%），‘粉蓝’苯环类含量最高（42.58%）。（3）5 个品种中，‘杰兔’的香气 成分总含量最高，为172 872.20 ng‧g-1，其次是‘灿烂’，为162 200.87 ng‧g-1；‘顶峰’和‘粉 蓝’的香气成分总含量较低，分别为91 284.45 ng‧g-1 和97 511.10 ng‧g-1。5 个兔眼蓝莓品种在 香气成分和含量上表现出显著差异，这些差异为蓝莓品种的优选和深加工原料的选择提供了 重要依据。
分类： 护理学 >> 护理学 提交时间： 2024-04-14
摘要： 目的 总结TCD发泡试验在缺血性脑卒中患者人群中应用的操作及护理经验。方法 回顾性分析2023年1月-2023年7月，我院40名神经内科缺血性脑卒中患者群体进行TCD发泡试验的资料，分析总结对缺血性脑卒中患者人群的操作及护理要点。结果 40例患者中11名患者为卵圆孔未闭，TCD发泡试验阳性，结论 TCD发泡试验可及时发现患者潜在脑梗死危险因素，对预防脑梗死的复发、提高患者的生活质量具有重大意义。对患者进行针对性护理可有效缓解患者在试验中的紧张情绪，提高患者配合程度。
分类： 生物学 >> 生物物理学 分类： 化学 >> 物理化学 分类： 生物学 >> 生物物理学 提交时间： 2024-04-16
摘要： Transcription factor (TF) are proteins that regulates the transcription of genetic information from DNA to messenger RNA by binding to a specific DNA sequence.Nucleic acid-protein interactions are crucial in regulating transcription in biological systems. This work presents a quick and convenient method for constructing tight-binding models and offers physical insights into the electronic structure properties of transcription factor complexes and DNA motifs. The tight binding Hamiltonian parameters are generated using the random forest regression algorithm, which reproduces the given ab-initiolevel calculations with reasonable accuracy. We present a library of residue-level parameters derived from extensive electronic structure calculations over various possible combinations of nucleobases and amino acid side chains from high-quality DNA-protein complex structures. As an example, our approach can reasonably generate the subtle electronic structure details for the orthologous transcription factors human AP-1 and Epstein-Barr virus Zta within a few seconds on a laptop. This method potentially enhances our understanding of the electronic structure variationsof gene-protein interaction complexes, even those involving dozens of proteins and genes. We hope this study offers a powerful tool for analyzing transcription regulation mechanisms at an electronic structural level.
分类： 图书馆学、情报学 >> 图书馆学 提交时间： 2024-04-15
摘要： 目的/意义 开放科学强调科研成果的社会影响力，学术图书作为哲学社会科学研究成果的重要表现形式，有必要对其社会影响力进行评价研究。 方法/过程 结合已有研究和开放科学环境下学术图书在线交流特点，基于国内网络媒体平台挖掘Altmetrics指标，探索建立一套评价哲学社会科学学术图书社会影响力的指标体系，并以14-16届江苏省哲学社会科学优秀成果奖获奖图书为研究样本，采用主成分分析法进行赋权分析。 结果/结论 哲学社会科学学术图书Altmetrics指标数据相差较大，不同平台指标之间相关性偏低；高质量学术图书的社会影响力存在较大差距；不同评价维度下，哲学社会科学学术图书的影响力存在明显差别。作者需增强开放科学理念，重视并主动通过多种网络平台宣传学术图书；推动建立社会影响力数据集成平台，保障数据有效性和稳定性；加强图书社会影响力的评价，更全面评价哲社学术图书影响力；建议出台相关政策，激励学术图书社会影响力的提升。
分类： 图书馆学、情报学 >> 读者工作 提交时间： 2024-04-16
摘要： 目的/意义］早期互联网的免费逻辑导致大量“潜水用户”形成了一种心理惯性，即认为互联网上的问答内容应当是免费的。这严重影响了用户从免费到付费的转移，因此揭示用户从免费知识问答转向付费知识问答的影响因素意义重大。［方法/过程］基于推-拉-锚定模型（PPM）和现状偏见理论（SQB），将不满意、知识焦虑作为推力，感知相对优势和服务质量作为拉力，免费心理惯性作为锚定力，构建了用户转移意愿影响因素模型。通过回收391份调研问卷，运用结构方程模型对模型进行假设检验。［结果/结论］拉力（不满意与知识焦虑）和推力（感知相对优势与服务质量）均正向影响用户转移意愿；而免费心理作为锚定力不仅直接阻碍用户转移还负向调节感知相对优势、服务质量与转移意愿之间的关系；此外，研究发现免费心理是由习惯、不确定性成本和沉没成本相互作用形成的。研究结论为在线问答平台制定差异化营销策略提供了有价值的见解。
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： we investigate the transmission of probe laser beam in a coupled-cavity system with polaritons by using standard input-output relation of optical fields, and proposed a theoretical schema for realizing a polariton-based photonic transistor. On account of effects of exciton-photon coupling and single-photon optomechanical coupling, a probe laser field can be either amplified or attenuated by another pump laser field when it passes through a coupled-cavity system with polaritons. The Stokes and anti-Stokes scattered effect of output prober laser can also be modulated. Our results open up exciting possibilities for designing photonic transistors.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： The miniaturization and mobility of computer vision systems are limited by the heavy computational burden and the size of optical lenses. Here, we propose to use a ultra-thin diffractive optical element to implement passive optical convolution. A division adjoint opto-electronic co-design method is also proposed. In our simulation experiments, the first few convolutional layers of the neural network can be replaced by optical convolution in a classification task on the CIFAR-10 dataset with no power consumption, while similar performance can be obtained.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： Diffraction gratings with high upward diffraction efficiency and large effective length are required for chip-scale light detection and ranging. In this paper, we propose a diffraction grating based on a multilayer silicon nitride waveguide, which theoretically achieves an upward diffraction efficiency of 92$\%$, a near-field effective length of 376 $\mu m$ and a far-field divergence angle of 0.105$^{\circ}$ at a wavelength of 850 nm. The diffraction grating has a high tolerance to process variations based on Monte Carlo Analysis. When the conditions are $\pm$5$\%$ layer thickness variation, $\pm$50 nm lithographic variation and $\pm$20 nm wavelength drift, more than 71$\%$ of the grating samples have a diffraction efficiency higher than 80$\%$, and 100$\%$ of the samples have an effective length larger than 200 $\mu m$ (corresponding to a far-field divergence <0.2$ ^{\circ}$). Furthermore, the near-field effective length of the grating with an upward diffraction efficiency above 90$\%$ can be adjusted from hundreds of microns to centimeters by changing the etching layer thickness and the grating duty cycle. This diffraction grating has potential application in optical sensing and imaging from visible to near-infrared wavelengths.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： Electromagnetic spins, including longitudinal and transverse ones, have been playing important roles in light-matter interactions. Here, we formulate a unified equation to uncover the physical origins and topological properties of longitudinal and transverse spins in a generic electromagnetic field. The equation reveals universally that the transverse spin is locked with the kinetic momentum and originated from the transverse inhomogeneities of field, whereas the helix-dependent longitudinal spin orients parallel to the local wavevector. Remarkably, a hidden extraordinary helix-dependent transverse spin possessing helix-dependent spin-momentum locking is discovered and the number of locking states consistent with the nontrivial topological spin Chern number. Furthermore, this spin which determines the inverted helical components is related to the Berry curvature closely. The findings, which are demonstrated experimentally by measuring the three-dimensional spin components in the focusing configuration, will deepen the understanding the underlying physics of spins and open an avenue for chiral quantum optical applications.
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： Optical forces in the near fields have important applications in on-chip optical manipulations of small particles and molecules. Here, we report a study of optical force and torque on small particles induced by the optical polarization singularities of a gold cylinder. We show that the scattering of the cylinder generates both electric and magnetic C lines (i.e., lines of polarization singularities) in the near fields, and the C lines can induce complex force and torque on a dielectric/magnetic particle. The force and torque manifest dramatic spatial variations with interesting symmetry properties, providing rich degrees of freedom for near-field optical manipulations. The study, for the first time to our knowledge, uncovers the effect of optical polarization singularities on light-induced force and torque on small particles. The results contribute to the understanding of chiral light-matter interactions and can find applications in on-chip optical manipulations and optical 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： Narrow linewidth laser(NLL) of high frequency stability and small form factor is essential to enable applications in long range sensing, quantum information and atomic clocks. Various high performance NLL have been demonstrated by Pound-Drever Hall(PDH) lock or self injection lock(SIL) of a seed laser to a vaccum-stabilized FP cavity of ultrahigh quality factor(Q). However they are often complicated lab setups due to the sophisticated stabilizing system and locking electronics. Here we report a compact NLL of 68mL volume, realized by SIL of a diode laser to a miniature FP cavity of 7.7x108 Q and 0.5mL volume, bypassing table-size vaccum, thermal and vibration isolation. We characterized the NLL with a self-delayed heterodyne system, the Lorentzian linewidth reaches 60mHz, and the integrated linewidth is ~80Hz. The frequency noise performance exceeds that of commercial NLLs and the best reported hybrid-integrated NLL realized by SIL to high Q on-chip ring resonators. Our work marks a major step toward a field-deployable NLL of superior performance utilizing ultra-high Q FP cavity.
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
Lingya Yu
Zengbo Wang
Lizhou Xu
Liyang Yue
Bing Yan
Igor V. Minin
Oleg V. Minin
Baidong Wu
Yiduo Chen
摘要： Photonic hook (PH) is a new type of artificial self-bending beam focused by a dielectric particle-lens with a curved waist smaller than the wavelength, which has the potential to revolutionize mesoscale photonics in many applications, e.g., optical trapping, signal switching, imaging, etc. In this paper, we discover a new mechanism that the highly curved PHs can be realised by the light interaction with the fully or partially metal-coated microchannels. The generated W-shaped and J-shaped PHs have bending angles exceeding 80-degree. Compared to other PH setups, the proposed design has a larger range to flexibly control the bending angle through the coating process and can be easily integrated with the established microfluidic systems.
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