太赫兹(THz)技术是一个不断发展的科学领域,其特征是频谱为0.1到10 THz。太赫兹(THz)波具有独特的物理特性,可产生多种生物学效应,如刺激细胞增殖、触发细胞凋亡、提高DNA甲基化水平、增强细胞膜通透性、增强基因表达、增强细胞炎症反...太赫兹(THz)技术是一个不断发展的科学领域,其特征是频谱为0.1到10 THz。太赫兹(THz)波具有独特的物理特性,可产生多种生物学效应,如刺激细胞增殖、触发细胞凋亡、提高DNA甲基化水平、增强细胞膜通透性、增强基因表达、增强细胞炎症反应、影响神经元调控等。本文综述了THz波与生物分子的相互作用,重点阐述了THz辐射对肿瘤细胞生长抑制、诱导凋亡、生物分子甲基化等方面的影响。着重对电磁生物学的生物学效应进行研究,为电磁生物学的研究提供帮助和启示。Terahertz (THz) technology is a growing scientific field characterized by a spectrum of 0.1 to 10 THz. Terahertz (THz) waves have unique physical properties and can produce a variety of biological effects, such as stimulating cell proliferation, triggering apoptosis, increasing DNA methylation level, enhancing cell membrane permeability, enhancing gene expression, and enhancing cellular inflammatory response. This paper reviews the interaction between THz waves and biomolecules, focusing on the effects of THz radiation on tumor cell growth inhibition, apoptosis induction, and methylation of biomolecules. This paper focuses on the biological effects of electromagnetic biology to provide help and enlightenment for the research of electromagnetic biology.展开更多
高温超导体因其独特的电子性质和非常规超导行为而备受关注。尤其是高能离子注入、压力、电磁场等外部场引起的高温超导材料相变,已成为研究的热点。然而,相关的内在机理仍未完全被揭示。第一性原理计算被广泛认为是一种有效的方法,用...高温超导体因其独特的电子性质和非常规超导行为而备受关注。尤其是高能离子注入、压力、电磁场等外部场引起的高温超导材料相变,已成为研究的热点。然而,相关的内在机理仍未完全被揭示。第一性原理计算被广泛认为是一种有效的方法,用以深入探究其内在机理。本研究利用第一性原理计算,探讨了不同泛函(PBE, PBE + U, HSE06)对YBa2Cu3O7 (YBCO7)中氧缺失现象对电子转移性质及超导性能的影响。结果表明,氧的缺失显著改变能带结构,不同泛函预测的结果有很大偏差,三种不同泛函预测的YBa2Cu3O6 (YBCO6)的能隙范围分别为0 eV、0.88 eV和1.69 eV。较大的能隙表明材料呈现绝缘态,而没有能隙则表明材料仍保持金属性。通过与实验结果对比,我们发现HSE06泛函在描述该材料的金属–绝缘性相变方面较为合理,且能隙的存在与否主要受铜的dz2轨道影响,从PBE泛函计算中发现YBCO6没有带隙是因为Cu的dyz轨道占据。此外,O(4)缺失可导致材料c轴伸长,这一现象与实验中He离子辐照后材料的X射线衍射(XRD)分析结果趋势一致。我们的发现将有助于解释YBCO7在外部场作用下,尤其是He离子辐照引发的金属绝缘相变现象,将为高温超导材料及其器件应用提供理论基础和新思路。High-temperature superconductors have attracted significant attention due to their unique electronic properties and unconventional superconducting behavior. In particular, phase transitions of high-temperature superconducting materials induced by external fields such as high-energy ion implantation, pressure, and electromagnetic fields have become a research hotspot. However, the underlying mechanisms remain not fully understood. First-principles calculations are widely regarded as an effective method to explore these intrinsic mechanisms in depth. In this study, first-principles calculations are employed to investigate the effects of oxygen vacancy phenomena on the electronic transfer properties and superconducting performance of YBa2Cu3O7 (YBCO7) under different functionals (PBE, PBE + U, HSE06). The results show that oxygen vacancies significantly alter the band structure, with considerable discrepancies observed in the predictions of different functionals. The calculated band gap for YBa2Cu3O6 (YBCO6) ranges from 0 to 1.69 eV. A larger band gap suggests an insulating state, while the absence of a band gap indicates that the material remains metallic. By comparing the results with the experimental results, we find that the HSE06 functional provides the most reasonable predictions. The presence or absence of a band gap is primarily influenced by copper orbitals. Oxygen vacancy at O(4) can cause the material’s c-axis to elongate, which is consistent with the trends observed in X-ray diffraction (XRD) analysis of materials after He-ion irradiation in experiments. Our findings contribute to explaining the metal-insulator phase transition of YBCO₇ under external fields, especially He-ion irradiation, and provide a theoretical foundation and new insights for the development of high-temperature superconducting materials and their device applications.展开更多
精准测量满载和卸料时颗粒物质对筒仓内壁的法向应力,掌握应力随时间和高度的变化规律,与筒仓的安全运行密切相关。本文设计了一种基于全桥电路的电阻应变式传感器,通过搭建筒仓应力测量系统,采用均值粒径为1.29 mm的透明玻璃珠进行实验...精准测量满载和卸料时颗粒物质对筒仓内壁的法向应力,掌握应力随时间和高度的变化规律,与筒仓的安全运行密切相关。本文设计了一种基于全桥电路的电阻应变式传感器,通过搭建筒仓应力测量系统,采用均值粒径为1.29 mm的透明玻璃珠进行实验,测量筒仓静态堆积和卸料过程中的壁面法向应力。静态应力的测量结果表明,颗粒填充完成后,在圆柱形部分出现了静态应力随着高度的降低而减小的区域,这与Janssen模型不一致。然后我们分析了每一个检测点在卸料过程中动态应力最大值的时空分布,结果表明,动态应力最大值出现在圆柱形中下部分,而不是筒仓几何转变处。最后我们计算了最大动态应力与静态应力的比值,得到了每个检测点的超压系数,发现超压系数最大值出现在H = 215 mm处。该研究对筒仓结构设计具有重要意义,有助于对应力增幅显著的区域进行结构优化,为提高筒仓的安全性和耐久性提供了关键参考。Accurately measuring the normal pressure exerted by granular materials on the inner walls of silos during loading and unloading, and understanding the variation of pressure over time and height, is closely related to the safe operation of silos. This study designed a resistive strain gauge sensor based on a full-bridge circuit and constructed a silo pressure measurement system. Experiments were conducted using transparent glass beads with an average particle size of 1.29 mm to measure the normal pressure on the silo walls during static filling and unloading processes. The results of static pressure measurements showed that, after filling, a region in the cylindrical section exhibited a decrease in static pressure with decreasing height, which is inconsistent with the predictions of the Janssen model. Subsequently, we analyzed the spatiotemporal distribution of the maximum dynamic pressure at each measurement point during unloading. The results showed that the maximum dynamic pressure occurred in the lower-middle part of the cylindrical section rather than at the geometric transition of the silo. Finally, we calculated the ratio of the maximum dynamic pressure to the static pressure at each measurement point to obtain the overpressure coefficient, and found that the maximum overpressure coefficient appeared at H = 215 mm. This study is of great significance to the structural design of silos, as it helps optimize the structure in regions with significant pressure amplification during unloading, providing key references for improving the safety and durability of silo operations.展开更多
为了减缓温室效应,减少二氧化碳的排放量,二氧化碳的资源化利用无疑是有效加快实现“碳达峰”和“碳中和”目标的关键。通过综述目前二氧化碳的分离利用方法和封存技术,分析了二氧化碳在各个领域中的主要应用,并对二氧化碳的资源化研究...为了减缓温室效应,减少二氧化碳的排放量,二氧化碳的资源化利用无疑是有效加快实现“碳达峰”和“碳中和”目标的关键。通过综述目前二氧化碳的分离利用方法和封存技术,分析了二氧化碳在各个领域中的主要应用,并对二氧化碳的资源化研究发展方向进行了展望。In order to reduce the greenhouse effect and carbon dioxide emissions, the resource utilization of carbon dioxide is undoubtedly the key to effectively accelerating the realization of the goal of “carbon peak” and “carbon neutrality”. In this paper, the separation and utilization methods and storage technologies of carbon dioxide are reviewed, the main applications of carbon dioxide in various fields are analyzed, and the research and development direction of carbon dioxide resource utilization has prospected.展开更多
基于相变材料的热能储存系统被认为是提高能源效率和可持续性的最有效方法之一,近年来备受关注。由于相变材料储放热速率低,导热系数小,极大的限制了其实际应用。目前常用复合手段增强体系的导热性能,如插入翅片,引入高导热填料等。本...基于相变材料的热能储存系统被认为是提高能源效率和可持续性的最有效方法之一,近年来备受关注。由于相变材料储放热速率低,导热系数小,极大的限制了其实际应用。目前常用复合手段增强体系的导热性能,如插入翅片,引入高导热填料等。本文综述了国内外复合相变材料导热性能方面的研究进展,分类归纳了提高复合相变材料热导率的方法和导热增强机理,并对复合相变材料导热性能增强研究的挑战和前景进行了展望。Thermal energy storage systems based on phase change materials (PCMs) are considered to be one of the most effective approaches for improving energy efficiency and sustainability, and have attracted significant attention in recent years. However, their practical application is greatly limited due to the low heat storage and release rate as well as the small thermal conductivity of PCMs. Currently, composite methods such as the addition of fins and high thermal conductivity fillers are commonly employed to enhance the thermal conductivity of these systems. In this review, the research progress on thermal conductivity of composite phase change materials at home and abroad is presented, and the methods and mechanisms of improving thermal conductivity of composite phase change materials are classified and summarized. Finally, the main challenges and outlooks of composite phase change materials were outlined.展开更多
刺激响应水凝胶软致动器作为一种具备自适应变形能力的智能材料,近年来在软体机器人、生物医学、智能控制等领域引起了广泛关注。本文综述了刺激响应水凝胶软致动器的最新研究进展,重点分析了不同外界刺激(包括热、光、电、磁、pH、离...刺激响应水凝胶软致动器作为一种具备自适应变形能力的智能材料,近年来在软体机器人、生物医学、智能控制等领域引起了广泛关注。本文综述了刺激响应水凝胶软致动器的最新研究进展,重点分析了不同外界刺激(包括热、光、电、磁、pH、离子、氧化还原反应、溶剂等)对其性能的影响。同时,总结了水凝胶软致动器在智能夹具、智能开关、智能窗帘、仿生软体机器人及药物输送等应用领域的最新研究进展。最后,本文讨论了提升其性能和拓展应用的潜在途径,并对未来发展前景进行展望。Stimuli-responsive hydrogel actuators, as intelligent materials with adaptive deformation capabilities, have attracted widespread attention in recent years across various fields, including soft robotics, biomedical applications, and smart control. This review summarizes the latest research advancements in stimuli-responsive hydrogel actuators, with a particular focus on the impact of various external stimuli (such as temperature, light, electric fields, magnetic fields, pH, ions, redox reactions, and solvent) on their performance. Furthermore, the article provides an overview of recent progress in the application of hydrogel actuators in intelligent grippers, smart switches, smart curtains, biomimetic soft robots, and drug delivery systems. Finally, potential strategies for enhancing their performance and expanding their applications are discussed, along with an outlook on future development trends.展开更多
基于密度泛函理论的第一性原理计算方法,我们深入探索了石墨烯,锗烯以及二维类石墨烯碳化锗(2D-GeC)这一新兴材料的电子结构。我们具体分析了这三者材料的电子结构,能带性质以及电子态密度。基于密度泛函理论的第一性原理计算,发现单层...基于密度泛函理论的第一性原理计算方法,我们深入探索了石墨烯,锗烯以及二维类石墨烯碳化锗(2D-GeC)这一新兴材料的电子结构。我们具体分析了这三者材料的电子结构,能带性质以及电子态密度。基于密度泛函理论的第一性原理计算,发现单层GeC展现出了独特的直接带隙特性,其直接带隙宽度被精确计算为2.21 eV。通过单层面内应变,发现单层GeC具有可调节的能带结构。研究结果表明,二维GeC可能是光电子学(如发光二极管、光电二极管和太阳能电池)的理想候选材料。Using first-principles calculation methods based on density functional theory, we conducted an in-depth exploration of the electronic structures of graphene, germanene, and the emerging material of two-dimensional graphene-like germanium carbide (2D-GeC). We specifically analyzed the electronic structures, band properties, and electron density of states for these three materials. Based on first-principles calculations within the framework of density functional theory, we found that monolayer GeC exhibits unique direct bandgap characteristics, with its direct bandgap width precisely calculated to be 2.21 eV. Through the application of in-plane strain to the monolayer, we discovered that monolayer GeC possesses tunable band structures. The research results indicate that two-dimensional GeC may be an ideal candidate material for optoelectronics, such as light-emitting diodes, photodiodes, and solar cells.展开更多
基于密度泛函理论的第一性原理计算研究了WS2/AlN异质双层的电子结构和能带性质。在本文所考虑的六种WS2/AlN异质双层体系中,A1堆叠构型(W原子排列在N原子上,S原子排列在Al原子上)是最稳定的结构。所有WS2/AlN异质双层体系都具有Ⅱ型能...基于密度泛函理论的第一性原理计算研究了WS2/AlN异质双层的电子结构和能带性质。在本文所考虑的六种WS2/AlN异质双层体系中,A1堆叠构型(W原子排列在N原子上,S原子排列在Al原子上)是最稳定的结构。所有WS2/AlN异质双层体系都具有Ⅱ型能带结构,其本征带隙值范围为1.45~1.82 eV,可以有效地分离光和电子–空穴对。从我们的研究结果来看,可以通过不同的堆叠方式来调节电子性质和带隙宽度,同时还能保证Ⅱ型能带对准。对结合能和层间距的计算也揭示了稳定性与不同堆叠方式之间的关系。这种控制表明了WS2/AlN异质结构在未来原子尺度的电子器件中的应用潜能。First-principles calculations based on density functional theory (DFT) have been employed to investigate the electronic structure and band properties of WS2/AlN heterobilayers. Among the six WS2/AlN heterobilayers configurations considered in this study, the A1 stacking configuration (where W atoms are aligned above N atoms and S atoms are aligned above Al atoms) is identified as the most stable structure. All WS2/AlN heterobilayer systems exhibit type-II band alignment, with intrinsic band gap values ranging from 1.45 eV to 1.82 eV, enabling efficient separation of photons and electron-hole pairs. According to our findings, electronic properties and band gap widths can be tuned through different stacking configurations while maintaining type-II band alignment. Calculations of binding energy and interlayer spacing also reveal the relationship between stability and various stacking patterns. This degree of control indicates the potential application of WS2/AlN heterobilayers in future atomic-scale electronic devices.展开更多
本文介绍了WO3薄膜电致变色机理,总结了电致变色器件的性能四项评价指标:光学调制幅度、响应时间、着色效率和循环稳定性,其中光学调制幅度是评价电致变色器件性能的关键参数。概述了WO3薄膜四种主要制备技术:溶胶–凝胶技术、电化学沉...本文介绍了WO3薄膜电致变色机理,总结了电致变色器件的性能四项评价指标:光学调制幅度、响应时间、着色效率和循环稳定性,其中光学调制幅度是评价电致变色器件性能的关键参数。概述了WO3薄膜四种主要制备技术:溶胶–凝胶技术、电化学沉积技术、电子束蒸发技术和磁控溅射技术,并综述了近几年使用这几种技术制备WO3薄膜的研究工作,通过对比分析,磁控溅射技术制备的WO3薄膜附着力强,光学调制幅度高,循环稳定性好,是最有前景的一项WO3薄膜制备技术。最后,文章对该电致变色技术领域未来的研究方向进行了展望:柔性衬底以及全固态电解质可能会被广泛使用。In this paper, the electrochromic mechanism of WO3 thin films is introduced, and four evaluation indexes of the performance of electrochromic devices are summarized: optical modulation amplitude, response time, coloring efficiency and cycling stability, among which optical modulation amplitude is the key parameter to evaluate the performance of electrochromic devices. This paper summarizes the four main preparation technologies of WO3 films: sol-gel technology, electrochemical deposition technology, electron beam evaporation technology and magnetron sputtering technology, and summarizes the research work on the preparation of WO3 films using these technologies in recent years. Finally, the paper looks forward to future research in the field of electrochromic technology, where flexible substrates and all-solid-state electrolytes may be widely used.展开更多
碘量法是测试天然气硫化氢含量的重要方法,测试过程会存在滴定速率的影响、吸收速率的影响、吸收临界的控制、井口吸收不充分,冬季受限大,流量计与吸收液结冰等问题,通过大量实验分析各种影响因素,对装置进行改进,使用气瓶代替井口吸收...碘量法是测试天然气硫化氢含量的重要方法,测试过程会存在滴定速率的影响、吸收速率的影响、吸收临界的控制、井口吸收不充分,冬季受限大,流量计与吸收液结冰等问题,通过大量实验分析各种影响因素,对装置进行改进,使用气瓶代替井口吸收,在室内通风环境下进行测试,控制滴定速率与吸收速率、用乙酸铬代替乙酸锌作吸收剂。实验证明,改进后的方法消除了上述影响,使测试结果更加准确有效。The iodine quantity method is an important method for testing the content of natural gas sulfide. The test process will have an impact on the titration rate, the impact of absorption rate, the control of the absorption of critical, the good absorption of the well is large, the winter is limited, the flowmeter and the absorption solution knot Ice and other issues, through a large number of experimental analysis of various influencing factors, improve the device, use gas cylinders instead of the well absorption, test in the indoor ventilation environment, control the fixed rate and absorption rate, and use chromium to replace zinc acetate as an absorbent. Experiments have shown that the improved method eliminates the above effects and makes the test results more accurate and effective.展开更多
大规模的石墨烯生产具有很高的商业价值,广泛应用于各个领域。将石墨剥离以得到石墨烯可以以极低的成本实现大规模生产,是当前最有前途的方法之一。本文综述了不同种类的机械剥离,对剥离机制的深入了解可以为实现高质量的石墨烯剥离技...大规模的石墨烯生产具有很高的商业价值,广泛应用于各个领域。将石墨剥离以得到石墨烯可以以极低的成本实现大规模生产,是当前最有前途的方法之一。本文综述了不同种类的机械剥离,对剥离机制的深入了解可以为实现高质量的石墨烯剥离技术的优化提供有效的指导。我们收集分析了近年来在石墨烯生产的机械剥离方面的最新进展,如已经广泛应用的超声剥离法,球磨剥离法,利用流体动力学实现剥离的方法,以及具有创新性的超临界剥离法。同时我们还展望了如何利用机械剥离技术获取高质量的石墨烯,希望这篇综述可以为石墨烯的生产发展指明一个方向。Large-scale graphene production holds significant commercial value and is widely used across various fields. The exfoliation of graphite to obtain graphene can achieve large-scale production at a very low cost, making it one of the most promising methods currently available. This article reviews different types of mechanical exfoliation. A deep understanding of the exfoliation mechanisms can provide effective guidance for optimizing high-quality graphene exfoliation technology. We have collected and analyzed the latest advancements in mechanical exfoliation for graphene production in recent years, such as the widely used ultrasonic exfoliation method, ball milling exfoliation, methods utilizing fluid dynamics for exfoliation, and the innovative supercritical exfoliation method. Additionally, we look forward to how mechanical exfoliation technology can be utilized to obtain high-quality graphene. We hope this review can provide a direction for the development of graphene production.展开更多
本文通过搅拌铸造法制备了碳纤维/6061铝基复合材料,采用电子万能试验机和霍普金森压杆实验装置进行准静态与动态压缩性能。采用二波法处理动态压缩实验数据得到材料的应力应变曲线。实验结果表明,对金属铝进行合金化处理能够有效的提...本文通过搅拌铸造法制备了碳纤维/6061铝基复合材料,采用电子万能试验机和霍普金森压杆实验装置进行准静态与动态压缩性能。采用二波法处理动态压缩实验数据得到材料的应力应变曲线。实验结果表明,对金属铝进行合金化处理能够有效的提高其动态力学性能,同一冲击气压下未添加碳纤维的6061铝合金材料的最大应力低于碳纤维/6061铝合金复合材料,且在一定情况下随碳纤维的含量成正比变化。In this paper, carbon fibers/6061 aluminum matrix composite was prepared by stirring casting method. The quasi-static and dynamic compression properties were studied by electronic universal testing machine and Hopkinson pressure bar test device. The stress-strain curve of the material was obtained by using two-wave method to process the experimental data of dynamic compression. The experimental results show that alloying can effectively improve the dynamic mechanical properties of aluminum. Under the same impact pressure, the maximum stress of 6061 aluminum alloy without adding carbon fiber is lower than that of carbon fibers/6061 aluminum matrix composites, and it is proportional to the content of carbon fiber under certain circumstances.展开更多
采用水热法合成了Mo-Nb2O5/C纳米片复合材料,对该材料进行形貌、结构表征和电化学性能测试。结果表明,通过钼掺杂碳复合提高了Nb2O5纳米片材料的电子电导率,从而改善了Nb2O5材料的电化学性能。3% Mo-Nb2O5/C-8复合材料具有最佳的电化学...采用水热法合成了Mo-Nb2O5/C纳米片复合材料,对该材料进行形貌、结构表征和电化学性能测试。结果表明,通过钼掺杂碳复合提高了Nb2O5纳米片材料的电子电导率,从而改善了Nb2O5材料的电化学性能。3% Mo-Nb2O5/C-8复合材料具有最佳的电化学性能,表现出优异的循环稳定性及倍率性能。在电流密度为100 mA g−1、电压范围在0.01~3.0 V的条件下,100周循环后,放电比容量为172.8 mAh g−1,容量保持率为84.9%;在500 mA g−1的高电流密度下,500周循环后,仍有119.2 mAh g−1的放电比容量,容量保持率为76.0%。展开更多
片上集成光学模块具有集成小型化、低成本等优点,可在芯片尺度上实现“样品进、结果出”的即时定点检测。本文研制了一个工作波长为647 nm的荧光激发模块,集成聚合酶链式反应(PCR)生物微流控芯片和光电探测器,实现了片上荧光激发和病原...片上集成光学模块具有集成小型化、低成本等优点,可在芯片尺度上实现“样品进、结果出”的即时定点检测。本文研制了一个工作波长为647 nm的荧光激发模块,集成聚合酶链式反应(PCR)生物微流控芯片和光电探测器,实现了片上荧光激发和病原体核酸检测。该荧光激发模块主要由光栅和多模干涉器两个微纳器件构成,经有限时域差分法优化,光栅激发效率可达26.3%,多模干涉器损耗低至2.8%。结合生物微流控芯片,采用等浓度梯度的Cyanine 5 (Cy5)荧光素溶液对荧光激发模块性能进行验证,光电探测器输出电压值与Cy5荧光素溶液浓度之间成线性关系,拟合曲线方差为0.9944,最低检测下限为0.0625 µmol/L。利用200 copies/μL的新型冠状病毒质粒做生物应用测试,结果表明本文所提出的荧光激发模块能满足实际PCR应用中对荧光信号激发的要求。本系统在生物荧光定量PCR、数字PCR、蛋白等实时生物荧光检测方面具有应用前景。On-chip integrated optical modules have the advantages of integrated miniaturization, low cost, etc., and can realize “sample in, result out” real-time fixed-point detection on a chip scale. In this paper, a fluorescence excitation module with an operating wavelength of 647 nm was developed to achieve on-chip fluorescence excitation and pathogen nucleic acid detection by integrating a polymerase chain reaction (PCR) bio-microfluidic chip and a photodetector. The fluorescence excitation module is mainly composed of two micro-nano devices, grating and multimode interferometer (MMI). Optimized by the Finite-difference time-domain method, the grating excitation efficiency can reach 26.3%, and the multimode interferometer loss is as low as 2.8%. The performance of the fluorescence excitation module was verified by using an equal concentration gradient of Cyanine 5 (Cy5) fluorescein solution in combination with a bio-microfluidic chip. The output voltage value of the photodetector and the concentration of Cy5 fluorescein solution were linearly correlated with the variance of the fitted curve being 0.9944, and the lowest limit of detection being 0.0625 µmol/L. Biological application tests were performed with 200 copies/μL of the SARS-CoV-2 plasmid, and the results show that the fluorescence excitation module proposed in this paper can meet the requirements for fluorescence signal excitation in practical PCR applications. This module has promising applications in real-time biofluorescence detection of biofluorescence quantitative PCR, digital PCR, and proteins.展开更多
文摘太赫兹(THz)技术是一个不断发展的科学领域,其特征是频谱为0.1到10 THz。太赫兹(THz)波具有独特的物理特性,可产生多种生物学效应,如刺激细胞增殖、触发细胞凋亡、提高DNA甲基化水平、增强细胞膜通透性、增强基因表达、增强细胞炎症反应、影响神经元调控等。本文综述了THz波与生物分子的相互作用,重点阐述了THz辐射对肿瘤细胞生长抑制、诱导凋亡、生物分子甲基化等方面的影响。着重对电磁生物学的生物学效应进行研究,为电磁生物学的研究提供帮助和启示。Terahertz (THz) technology is a growing scientific field characterized by a spectrum of 0.1 to 10 THz. Terahertz (THz) waves have unique physical properties and can produce a variety of biological effects, such as stimulating cell proliferation, triggering apoptosis, increasing DNA methylation level, enhancing cell membrane permeability, enhancing gene expression, and enhancing cellular inflammatory response. This paper reviews the interaction between THz waves and biomolecules, focusing on the effects of THz radiation on tumor cell growth inhibition, apoptosis induction, and methylation of biomolecules. This paper focuses on the biological effects of electromagnetic biology to provide help and enlightenment for the research of electromagnetic biology.
文摘高温超导体因其独特的电子性质和非常规超导行为而备受关注。尤其是高能离子注入、压力、电磁场等外部场引起的高温超导材料相变,已成为研究的热点。然而,相关的内在机理仍未完全被揭示。第一性原理计算被广泛认为是一种有效的方法,用以深入探究其内在机理。本研究利用第一性原理计算,探讨了不同泛函(PBE, PBE + U, HSE06)对YBa2Cu3O7 (YBCO7)中氧缺失现象对电子转移性质及超导性能的影响。结果表明,氧的缺失显著改变能带结构,不同泛函预测的结果有很大偏差,三种不同泛函预测的YBa2Cu3O6 (YBCO6)的能隙范围分别为0 eV、0.88 eV和1.69 eV。较大的能隙表明材料呈现绝缘态,而没有能隙则表明材料仍保持金属性。通过与实验结果对比,我们发现HSE06泛函在描述该材料的金属–绝缘性相变方面较为合理,且能隙的存在与否主要受铜的dz2轨道影响,从PBE泛函计算中发现YBCO6没有带隙是因为Cu的dyz轨道占据。此外,O(4)缺失可导致材料c轴伸长,这一现象与实验中He离子辐照后材料的X射线衍射(XRD)分析结果趋势一致。我们的发现将有助于解释YBCO7在外部场作用下,尤其是He离子辐照引发的金属绝缘相变现象,将为高温超导材料及其器件应用提供理论基础和新思路。High-temperature superconductors have attracted significant attention due to their unique electronic properties and unconventional superconducting behavior. In particular, phase transitions of high-temperature superconducting materials induced by external fields such as high-energy ion implantation, pressure, and electromagnetic fields have become a research hotspot. However, the underlying mechanisms remain not fully understood. First-principles calculations are widely regarded as an effective method to explore these intrinsic mechanisms in depth. In this study, first-principles calculations are employed to investigate the effects of oxygen vacancy phenomena on the electronic transfer properties and superconducting performance of YBa2Cu3O7 (YBCO7) under different functionals (PBE, PBE + U, HSE06). The results show that oxygen vacancies significantly alter the band structure, with considerable discrepancies observed in the predictions of different functionals. The calculated band gap for YBa2Cu3O6 (YBCO6) ranges from 0 to 1.69 eV. A larger band gap suggests an insulating state, while the absence of a band gap indicates that the material remains metallic. By comparing the results with the experimental results, we find that the HSE06 functional provides the most reasonable predictions. The presence or absence of a band gap is primarily influenced by copper orbitals. Oxygen vacancy at O(4) can cause the material’s c-axis to elongate, which is consistent with the trends observed in X-ray diffraction (XRD) analysis of materials after He-ion irradiation in experiments. Our findings contribute to explaining the metal-insulator phase transition of YBCO₇ under external fields, especially He-ion irradiation, and provide a theoretical foundation and new insights for the development of high-temperature superconducting materials and their device applications.
文摘精准测量满载和卸料时颗粒物质对筒仓内壁的法向应力,掌握应力随时间和高度的变化规律,与筒仓的安全运行密切相关。本文设计了一种基于全桥电路的电阻应变式传感器,通过搭建筒仓应力测量系统,采用均值粒径为1.29 mm的透明玻璃珠进行实验,测量筒仓静态堆积和卸料过程中的壁面法向应力。静态应力的测量结果表明,颗粒填充完成后,在圆柱形部分出现了静态应力随着高度的降低而减小的区域,这与Janssen模型不一致。然后我们分析了每一个检测点在卸料过程中动态应力最大值的时空分布,结果表明,动态应力最大值出现在圆柱形中下部分,而不是筒仓几何转变处。最后我们计算了最大动态应力与静态应力的比值,得到了每个检测点的超压系数,发现超压系数最大值出现在H = 215 mm处。该研究对筒仓结构设计具有重要意义,有助于对应力增幅显著的区域进行结构优化,为提高筒仓的安全性和耐久性提供了关键参考。Accurately measuring the normal pressure exerted by granular materials on the inner walls of silos during loading and unloading, and understanding the variation of pressure over time and height, is closely related to the safe operation of silos. This study designed a resistive strain gauge sensor based on a full-bridge circuit and constructed a silo pressure measurement system. Experiments were conducted using transparent glass beads with an average particle size of 1.29 mm to measure the normal pressure on the silo walls during static filling and unloading processes. The results of static pressure measurements showed that, after filling, a region in the cylindrical section exhibited a decrease in static pressure with decreasing height, which is inconsistent with the predictions of the Janssen model. Subsequently, we analyzed the spatiotemporal distribution of the maximum dynamic pressure at each measurement point during unloading. The results showed that the maximum dynamic pressure occurred in the lower-middle part of the cylindrical section rather than at the geometric transition of the silo. Finally, we calculated the ratio of the maximum dynamic pressure to the static pressure at each measurement point to obtain the overpressure coefficient, and found that the maximum overpressure coefficient appeared at H = 215 mm. This study is of great significance to the structural design of silos, as it helps optimize the structure in regions with significant pressure amplification during unloading, providing key references for improving the safety and durability of silo operations.
文摘为了减缓温室效应,减少二氧化碳的排放量,二氧化碳的资源化利用无疑是有效加快实现“碳达峰”和“碳中和”目标的关键。通过综述目前二氧化碳的分离利用方法和封存技术,分析了二氧化碳在各个领域中的主要应用,并对二氧化碳的资源化研究发展方向进行了展望。In order to reduce the greenhouse effect and carbon dioxide emissions, the resource utilization of carbon dioxide is undoubtedly the key to effectively accelerating the realization of the goal of “carbon peak” and “carbon neutrality”. In this paper, the separation and utilization methods and storage technologies of carbon dioxide are reviewed, the main applications of carbon dioxide in various fields are analyzed, and the research and development direction of carbon dioxide resource utilization has prospected.
文摘基于相变材料的热能储存系统被认为是提高能源效率和可持续性的最有效方法之一,近年来备受关注。由于相变材料储放热速率低,导热系数小,极大的限制了其实际应用。目前常用复合手段增强体系的导热性能,如插入翅片,引入高导热填料等。本文综述了国内外复合相变材料导热性能方面的研究进展,分类归纳了提高复合相变材料热导率的方法和导热增强机理,并对复合相变材料导热性能增强研究的挑战和前景进行了展望。Thermal energy storage systems based on phase change materials (PCMs) are considered to be one of the most effective approaches for improving energy efficiency and sustainability, and have attracted significant attention in recent years. However, their practical application is greatly limited due to the low heat storage and release rate as well as the small thermal conductivity of PCMs. Currently, composite methods such as the addition of fins and high thermal conductivity fillers are commonly employed to enhance the thermal conductivity of these systems. In this review, the research progress on thermal conductivity of composite phase change materials at home and abroad is presented, and the methods and mechanisms of improving thermal conductivity of composite phase change materials are classified and summarized. Finally, the main challenges and outlooks of composite phase change materials were outlined.
文摘刺激响应水凝胶软致动器作为一种具备自适应变形能力的智能材料,近年来在软体机器人、生物医学、智能控制等领域引起了广泛关注。本文综述了刺激响应水凝胶软致动器的最新研究进展,重点分析了不同外界刺激(包括热、光、电、磁、pH、离子、氧化还原反应、溶剂等)对其性能的影响。同时,总结了水凝胶软致动器在智能夹具、智能开关、智能窗帘、仿生软体机器人及药物输送等应用领域的最新研究进展。最后,本文讨论了提升其性能和拓展应用的潜在途径,并对未来发展前景进行展望。Stimuli-responsive hydrogel actuators, as intelligent materials with adaptive deformation capabilities, have attracted widespread attention in recent years across various fields, including soft robotics, biomedical applications, and smart control. This review summarizes the latest research advancements in stimuli-responsive hydrogel actuators, with a particular focus on the impact of various external stimuli (such as temperature, light, electric fields, magnetic fields, pH, ions, redox reactions, and solvent) on their performance. Furthermore, the article provides an overview of recent progress in the application of hydrogel actuators in intelligent grippers, smart switches, smart curtains, biomimetic soft robots, and drug delivery systems. Finally, potential strategies for enhancing their performance and expanding their applications are discussed, along with an outlook on future development trends.
文摘基于密度泛函理论的第一性原理计算方法,我们深入探索了石墨烯,锗烯以及二维类石墨烯碳化锗(2D-GeC)这一新兴材料的电子结构。我们具体分析了这三者材料的电子结构,能带性质以及电子态密度。基于密度泛函理论的第一性原理计算,发现单层GeC展现出了独特的直接带隙特性,其直接带隙宽度被精确计算为2.21 eV。通过单层面内应变,发现单层GeC具有可调节的能带结构。研究结果表明,二维GeC可能是光电子学(如发光二极管、光电二极管和太阳能电池)的理想候选材料。Using first-principles calculation methods based on density functional theory, we conducted an in-depth exploration of the electronic structures of graphene, germanene, and the emerging material of two-dimensional graphene-like germanium carbide (2D-GeC). We specifically analyzed the electronic structures, band properties, and electron density of states for these three materials. Based on first-principles calculations within the framework of density functional theory, we found that monolayer GeC exhibits unique direct bandgap characteristics, with its direct bandgap width precisely calculated to be 2.21 eV. Through the application of in-plane strain to the monolayer, we discovered that monolayer GeC possesses tunable band structures. The research results indicate that two-dimensional GeC may be an ideal candidate material for optoelectronics, such as light-emitting diodes, photodiodes, and solar cells.
文摘基于密度泛函理论的第一性原理计算研究了WS2/AlN异质双层的电子结构和能带性质。在本文所考虑的六种WS2/AlN异质双层体系中,A1堆叠构型(W原子排列在N原子上,S原子排列在Al原子上)是最稳定的结构。所有WS2/AlN异质双层体系都具有Ⅱ型能带结构,其本征带隙值范围为1.45~1.82 eV,可以有效地分离光和电子–空穴对。从我们的研究结果来看,可以通过不同的堆叠方式来调节电子性质和带隙宽度,同时还能保证Ⅱ型能带对准。对结合能和层间距的计算也揭示了稳定性与不同堆叠方式之间的关系。这种控制表明了WS2/AlN异质结构在未来原子尺度的电子器件中的应用潜能。First-principles calculations based on density functional theory (DFT) have been employed to investigate the electronic structure and band properties of WS2/AlN heterobilayers. Among the six WS2/AlN heterobilayers configurations considered in this study, the A1 stacking configuration (where W atoms are aligned above N atoms and S atoms are aligned above Al atoms) is identified as the most stable structure. All WS2/AlN heterobilayer systems exhibit type-II band alignment, with intrinsic band gap values ranging from 1.45 eV to 1.82 eV, enabling efficient separation of photons and electron-hole pairs. According to our findings, electronic properties and band gap widths can be tuned through different stacking configurations while maintaining type-II band alignment. Calculations of binding energy and interlayer spacing also reveal the relationship between stability and various stacking patterns. This degree of control indicates the potential application of WS2/AlN heterobilayers in future atomic-scale electronic devices.
文摘本文介绍了WO3薄膜电致变色机理,总结了电致变色器件的性能四项评价指标:光学调制幅度、响应时间、着色效率和循环稳定性,其中光学调制幅度是评价电致变色器件性能的关键参数。概述了WO3薄膜四种主要制备技术:溶胶–凝胶技术、电化学沉积技术、电子束蒸发技术和磁控溅射技术,并综述了近几年使用这几种技术制备WO3薄膜的研究工作,通过对比分析,磁控溅射技术制备的WO3薄膜附着力强,光学调制幅度高,循环稳定性好,是最有前景的一项WO3薄膜制备技术。最后,文章对该电致变色技术领域未来的研究方向进行了展望:柔性衬底以及全固态电解质可能会被广泛使用。In this paper, the electrochromic mechanism of WO3 thin films is introduced, and four evaluation indexes of the performance of electrochromic devices are summarized: optical modulation amplitude, response time, coloring efficiency and cycling stability, among which optical modulation amplitude is the key parameter to evaluate the performance of electrochromic devices. This paper summarizes the four main preparation technologies of WO3 films: sol-gel technology, electrochemical deposition technology, electron beam evaporation technology and magnetron sputtering technology, and summarizes the research work on the preparation of WO3 films using these technologies in recent years. Finally, the paper looks forward to future research in the field of electrochromic technology, where flexible substrates and all-solid-state electrolytes may be widely used.
文摘碘量法是测试天然气硫化氢含量的重要方法,测试过程会存在滴定速率的影响、吸收速率的影响、吸收临界的控制、井口吸收不充分,冬季受限大,流量计与吸收液结冰等问题,通过大量实验分析各种影响因素,对装置进行改进,使用气瓶代替井口吸收,在室内通风环境下进行测试,控制滴定速率与吸收速率、用乙酸铬代替乙酸锌作吸收剂。实验证明,改进后的方法消除了上述影响,使测试结果更加准确有效。The iodine quantity method is an important method for testing the content of natural gas sulfide. The test process will have an impact on the titration rate, the impact of absorption rate, the control of the absorption of critical, the good absorption of the well is large, the winter is limited, the flowmeter and the absorption solution knot Ice and other issues, through a large number of experimental analysis of various influencing factors, improve the device, use gas cylinders instead of the well absorption, test in the indoor ventilation environment, control the fixed rate and absorption rate, and use chromium to replace zinc acetate as an absorbent. Experiments have shown that the improved method eliminates the above effects and makes the test results more accurate and effective.
文摘大规模的石墨烯生产具有很高的商业价值,广泛应用于各个领域。将石墨剥离以得到石墨烯可以以极低的成本实现大规模生产,是当前最有前途的方法之一。本文综述了不同种类的机械剥离,对剥离机制的深入了解可以为实现高质量的石墨烯剥离技术的优化提供有效的指导。我们收集分析了近年来在石墨烯生产的机械剥离方面的最新进展,如已经广泛应用的超声剥离法,球磨剥离法,利用流体动力学实现剥离的方法,以及具有创新性的超临界剥离法。同时我们还展望了如何利用机械剥离技术获取高质量的石墨烯,希望这篇综述可以为石墨烯的生产发展指明一个方向。Large-scale graphene production holds significant commercial value and is widely used across various fields. The exfoliation of graphite to obtain graphene can achieve large-scale production at a very low cost, making it one of the most promising methods currently available. This article reviews different types of mechanical exfoliation. A deep understanding of the exfoliation mechanisms can provide effective guidance for optimizing high-quality graphene exfoliation technology. We have collected and analyzed the latest advancements in mechanical exfoliation for graphene production in recent years, such as the widely used ultrasonic exfoliation method, ball milling exfoliation, methods utilizing fluid dynamics for exfoliation, and the innovative supercritical exfoliation method. Additionally, we look forward to how mechanical exfoliation technology can be utilized to obtain high-quality graphene. We hope this review can provide a direction for the development of graphene production.
文摘本文通过搅拌铸造法制备了碳纤维/6061铝基复合材料,采用电子万能试验机和霍普金森压杆实验装置进行准静态与动态压缩性能。采用二波法处理动态压缩实验数据得到材料的应力应变曲线。实验结果表明,对金属铝进行合金化处理能够有效的提高其动态力学性能,同一冲击气压下未添加碳纤维的6061铝合金材料的最大应力低于碳纤维/6061铝合金复合材料,且在一定情况下随碳纤维的含量成正比变化。In this paper, carbon fibers/6061 aluminum matrix composite was prepared by stirring casting method. The quasi-static and dynamic compression properties were studied by electronic universal testing machine and Hopkinson pressure bar test device. The stress-strain curve of the material was obtained by using two-wave method to process the experimental data of dynamic compression. The experimental results show that alloying can effectively improve the dynamic mechanical properties of aluminum. Under the same impact pressure, the maximum stress of 6061 aluminum alloy without adding carbon fiber is lower than that of carbon fibers/6061 aluminum matrix composites, and it is proportional to the content of carbon fiber under certain circumstances.
文摘采用水热法合成了Mo-Nb2O5/C纳米片复合材料,对该材料进行形貌、结构表征和电化学性能测试。结果表明,通过钼掺杂碳复合提高了Nb2O5纳米片材料的电子电导率,从而改善了Nb2O5材料的电化学性能。3% Mo-Nb2O5/C-8复合材料具有最佳的电化学性能,表现出优异的循环稳定性及倍率性能。在电流密度为100 mA g−1、电压范围在0.01~3.0 V的条件下,100周循环后,放电比容量为172.8 mAh g−1,容量保持率为84.9%;在500 mA g−1的高电流密度下,500周循环后,仍有119.2 mAh g−1的放电比容量,容量保持率为76.0%。
文摘片上集成光学模块具有集成小型化、低成本等优点,可在芯片尺度上实现“样品进、结果出”的即时定点检测。本文研制了一个工作波长为647 nm的荧光激发模块,集成聚合酶链式反应(PCR)生物微流控芯片和光电探测器,实现了片上荧光激发和病原体核酸检测。该荧光激发模块主要由光栅和多模干涉器两个微纳器件构成,经有限时域差分法优化,光栅激发效率可达26.3%,多模干涉器损耗低至2.8%。结合生物微流控芯片,采用等浓度梯度的Cyanine 5 (Cy5)荧光素溶液对荧光激发模块性能进行验证,光电探测器输出电压值与Cy5荧光素溶液浓度之间成线性关系,拟合曲线方差为0.9944,最低检测下限为0.0625 µmol/L。利用200 copies/μL的新型冠状病毒质粒做生物应用测试,结果表明本文所提出的荧光激发模块能满足实际PCR应用中对荧光信号激发的要求。本系统在生物荧光定量PCR、数字PCR、蛋白等实时生物荧光检测方面具有应用前景。On-chip integrated optical modules have the advantages of integrated miniaturization, low cost, etc., and can realize “sample in, result out” real-time fixed-point detection on a chip scale. In this paper, a fluorescence excitation module with an operating wavelength of 647 nm was developed to achieve on-chip fluorescence excitation and pathogen nucleic acid detection by integrating a polymerase chain reaction (PCR) bio-microfluidic chip and a photodetector. The fluorescence excitation module is mainly composed of two micro-nano devices, grating and multimode interferometer (MMI). Optimized by the Finite-difference time-domain method, the grating excitation efficiency can reach 26.3%, and the multimode interferometer loss is as low as 2.8%. The performance of the fluorescence excitation module was verified by using an equal concentration gradient of Cyanine 5 (Cy5) fluorescein solution in combination with a bio-microfluidic chip. The output voltage value of the photodetector and the concentration of Cy5 fluorescein solution were linearly correlated with the variance of the fitted curve being 0.9944, and the lowest limit of detection being 0.0625 µmol/L. Biological application tests were performed with 200 copies/μL of the SARS-CoV-2 plasmid, and the results show that the fluorescence excitation module proposed in this paper can meet the requirements for fluorescence signal excitation in practical PCR applications. This module has promising applications in real-time biofluorescence detection of biofluorescence quantitative PCR, digital PCR, and proteins.
