electromagnetic field

电磁场
  • 文章类型: Journal Article
    功能性神经元是神经系统的基本组成部分,负责在身体不同部位之间传递信息。然而,关于神经元和磁场之间的相互作用知之甚少。在这项工作中,我们通过在FitzHugh-Nagumo神经元模型中引入通量控制的忆阻器,提出了一种新的功能神经元,场效应由忆阻器估计。我们研究了神经元的动力学和能量特征,并通过应用加性高斯噪声来考虑随机共振。在引入忆阻器之后,神经元的固有能量被放大。此外,随着忆阻器相关参数的变化,周期性振荡的能量大于相邻混沌振荡的能量,通过改变刺激相关参数可以获得相同的结果。此外,能量被证明是估计随机共振和逆随机共振的另一种有效方法。此外,模拟实现是为神经元的物理实现而实现的。这些结果为了解神经元检测电磁场的激发机制提供了启示。
    The functional neurons are basic building blocks of the nervous system and are responsible for transmitting information between different parts of the body. However, it is less known about the interaction between the neuron and the field. In this work, we propose a novel functional neuron by introducing a flux-controlled memristor into the FitzHugh-Nagumo neuron model, and the field effect is estimated by the memristor. We investigate the dynamics and energy characteristics of the neuron, and the stochastic resonance is also considered by applying the additive Gaussian noise. The intrinsic energy of the neuron is enlarged after introducing the memristor. Moreover, the energy of the periodic oscillation is larger than that of the adjacent chaotic oscillation with the changing of memristor-related parameters, and same results is obtained by varying stimuli-related parameters. In addition, the energy is proved to be another effective method to estimate stochastic resonance and inverse stochastic resonance. Furthermore, the analog implementation is achieved for the physical realization of the neuron. These results shed lights on the understanding of the firing mechanism for neurons detecting electromagnetic field.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    为了优化感应加热(IH)中间包的应用效果,以四通道IH中间包为研究对象。基于数值模拟方法,感应加热器和通道的不同相对放置角度对电磁场的影响,研究了中间包的流场和温度场。我们专注于比较通道的磁通密度(B)和电磁力(EMF)分布。结果表明,无论加热器和通道之间的相对放置角度如何,B在通道的中心圆形横截面中的分布是偏心的。当加热器绕通道1向中间包底部旋转时,B在通道的中心圆形横截面中的分布从水平偏心变为垂直偏心。通过对通道纵截面中B轮廓的分析,可以获得通道上部和下部之间的有效磁通密度面积差(ΔAB),从而定量分析B在本节中的分布。ΔAB的分布模式与电磁力在通道中心线的垂直方向(FZ)上的分布模式一致。随着加热器向下旋转,通道1的ΔAB和FZ逐渐增加。而通道2的那些在旋转角度为60°时达到最大值。与常规放置相比,当加热器旋转角度为60°时,通道1和通道2的出口流速分别下降15%和12%,分别。然而,通道2处的出口温度增加1.96K,并且在通道1和通道2的出口处的钢水流不再表现出显著的向下流动。这表明,当加热器旋转角度为60°时,它有双重优势。一方面,有助于减少钢水对槽道和出料室底部的侵蚀,另一方面,能更有效地发挥感应加热器对槽钢的加热作用。这为提高IH中间包的应用效果提供了新的途径。
    In order to optimize the application effect of induction heating (IH) tundishes, a four-channel IH tundish is taken as the research object. Based on numerical simulation methods, the influence of different relative placement angles of induction heaters and channels on the electromagnetic field, flow field and temperature field of the tundish is investigated. We focus on comparing the magnetic flux density (B) and electromagnetic force (EMF) distribution of the channel. The results show that regardless of the relative placement angle between the heater and the channel, the distribution of B in the central circular cross-section of the channel is eccentric. When the heater rotates around channel 1 towards the bottom of the tundish, the distribution of B in the central circular cross-section of the channel changes from a horizontal eccentricity to a vertical one. Through the analysis of the B contour in the longitudinal section of the channel, the difference in effective magnetic flux density area (ΔAB) between the upper and lower parts of the channel can be obtained, thereby quantitatively analyzing the distribution of B in this section. The distribution pattern of ΔAB is consistent with the distribution pattern of the electromagnetic force in the vertical direction (FZ) of the channel centerline. The ΔAB and FZ of channel 1 gradually increase as the heater rotates downwards, while those of channel 2 reach their maximum value at a rotation angle of 60°. Compared to the conventional placement, when the heater rotation angle is 60°, the outlet flow velocities at channel 1 and channel 2 decrease by 15% and 12%, respectively. However, the outlet temperature at channel 2 increases by 1.96 K, and the molten steel flow at the outlet of channel 1 and channel 2 no longer exhibits significant downward flow. This shows that when the heater rotation angle is 60°, it has a dual advantage. On the one hand, it is helpful to reduce the erosion of the molten steel on the channel and the bottom of the discharging chamber, and on the other hand, it can more effectively exert the heating effect of the induction heater on the molten steel in the channel. This presents a new approach to enhance the application effectiveness of IH tundish.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    磁性纳米材料修饰的微生物混杂体系在磁场的刺激下可以增强界面电子转移和能量转化。然而,混合系统的生物电催化性能仍有待提高,磁场诱导的生物电催化增强机制尚不清楚。在这项工作中,将γ-Fe2O3磁性纳米颗粒涂覆在希瓦氏菌CN32细胞表面上,然后放置在电磁场中。结果表明,电磁场能极大地促进细胞外电子传递,在电磁场作用下,CN32@γ-Fe2O3的氧化峰电流增加到2.24倍。其增强机制主要是由于表面修饰的微生物为细胞外膜细胞色素的高微生物催化活性提供了升高的接触面积,而磁性纳米颗粒在细胞质和外膜之间提供了一个网络接口,用于增强磁场中的快速多维电子传输路径。这项工作为磁场耦合的电活性微生物的合理设计以及用于快速电子转移过程的最佳界面结构的基本原理提供了新的科学思路。高效的生物能量转换。
    The microbial hybrid system modified by magnetic nanomaterials can enhance the interfacial electron transfer and energy conversion under the stimulation of a magnetic field. However, the bioelectrocatalytic performance of a hybrid system still needs to be improved, and the mechanism of magnetic field-induced bioelectrocatalytic enhancements is still unclear. In this work, γ-Fe2O3 magnetic nanoparticles were coated on a Shewanella putrefaciens CN32 cell surface and followed by placing in an electromagnetic field. The results showed that the electromagnetic field can greatly boost the extracellular electron transfer, and the oxidation peak current of CN32@γ-Fe2O3 increased to 2.24 times under an electromagnetic field. The enhancement mechanism is mainly due to the fact that the surface modified microorganism provides an elevated contact area for the high microbial catalytic activity of the outer cell membrane\'s cytochrome, while the magnetic nanoparticles provide a networked interface between the cytoplasm and the outer membrane for boosting the fast multidimensional electron transport path in the magnetic field. This work sheds fresh scientific light on the rational design of magnetic-field-coupled electroactive microorganisms and the fundamentals of an optimal interfacial structure for a fast electron transfer process toward an efficient bioenergy conversion.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    食用花由于其独特的感官特性和健康益处而成为人类饮食的异国情调的部分。由于消费者要求食用花卉及其产品具有天然的新鲜度和较高的营养价值,关于绿色高效食用花卉加工技术的应用研究日益增多。本文回顾了包括超声在内的许多物理领域的应用,微波炉,红外线,紫外线,电离辐射,脉冲电场,高静水压力,并降低压力,旨在提高食用花卉的加工和产品质量。作用机制,影响因素,并对每个物理能量场的应用状况进行了严格评估。此外,评估了每个能量场的优缺点,并强调了他们未来前景的趋势。预计未来的研究将集中在对基于物理场的技术应用于食用花卉加工时的机理作用的更多了解,并为拓宽基于物理场的技术在工业领域的应用提供基础。
    Edible flowers are an exotic part of the human diet due to their distinct sensorial properties and health benefits. Due to consumers demand edible flowers and their products with natural freshness and high nutritional value, there is increasing research on the application of green and efficient edible flower processing technologies. This paper reviews the application of a number of physical fields including ultrasound, microwave, infrared, ultraviolet, ionizing radiation, pulse electric field, high hydrostatic pressure, and reduced pressure aiming to improve the processing and product quality of edible flowers. The mechanism of action, influencing factors, and status on application of each physical energy field are critically evaluated. In addition, the advantages and disadvantages of each of these energy fields are evaluated, and trends on their future prospects are highlighted. Future research is expected to focus on gaining greater understanding of the mechanism action of physical field-based technologies when applied to processing of edible flowers and to provide the basis for broaden the application of physical field-based technologies in industrial realm.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    骨关节炎(OA)是一种严重损害生活质量的退行性疾病。迫切需要创新的OA疗法。虽然小的细胞外囊泡(sEV)对OA显示出有希望的治疗效果,它们有限的产量限制了临床翻译。这里,我们设计了一种新型的sEV生产系统,可以提高其产量和治疗性能。通过使用电磁场(EMF)结合超小超顺磁性氧化铁(USPIO)颗粒刺激间充质干细胞(MSC),我们获得了提高的EMF-USPIO-sEV产量。这些囊泡不仅激活合成代谢途径,而且抑制分解代谢活性,至关重要的是,它们促进M2巨噬细胞极化,辅助软骨再生。在前交叉韧带横断手术引发的OA小鼠模型中,EMF-USPIO-sEV降低OA严重程度,和增广矩阵合成。此外,他们通过microRNA-99b/MFG-E8/NF-κB信号轴减缓OA的进展.因此,EMF-USPIO-sEV为OA提供了一种潜在的治疗选择,通过调节基质稳态和巨噬细胞极化。
    Osteoarthritis (OA) is a degenerative disease that significantly impairs quality of life. There is a pressing need for innovative OA therapies. While small extracellular vesicles (sEVs) show promising therapeutic effects against OA, their limited yield restricts clinical translation. Here, we devised a novel production system for sEVs that enhances both their yield and therapeutic properties. By stimulating mesenchymal stem cells (MSCs) using electromagnetic field (EMF) combined with ultrasmall superparamagnetic iron oxide (USPIO) particles, we procured an augmented yield of EMF-USPIO-sEVs. These vesicles not only activate anabolic pathways but also inhibit catabolic activities, and crucially, they promote M2 macrophage polarization, aiding cartilage regeneration. In an OA mouse model triggered by anterior cruciate ligament transection surgery, EMF-USPIO-sEVs reduced OA severity, and augmented matrix synthesis. Moreover, they decelerated OA progression through the microRNA-99b/MFG-E8/NF-κB signaling axis. Consequently, EMF-USPIO-sEVs present a potential therapeutic option for OA, acting by modulating matrix homeostasis and macrophage polarization.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: English Abstract
    With the widespread use of electrical equipment, cognitive functions such as working memory (WM) could be severely affected when people are exposed to 50 Hz electromagnetic fields (EMF) for long term. However, the effects of EMF exposure on WM and its neural mechanism remain unclear. In the present paper, 15 rats were randomly assigned to three groups, and exposed to an EMF environment at 50 Hz and 2 mT for a different duration: 0 days (control group), 24 days (experimental group I), and 48 days (experimental group II). Then, their WM function was assessed by the T-maze task. Besides, their local field potential (LFP) in the media prefrontal cortex (mPFC) was recorded by the in vivo multichannel electrophysiological recording system to study the power spectral density (PSD) of θ and γ oscillations and the phase-amplitude coupling (PAC) intensity of θ-γ oscillations during the T-maze task. The results showed that the PSD of θ and γ oscillations decreased in experimental groups I and II, and the PAC intensity between θ and high-frequency γ (hγ) decreased significantly compared to the control group. The number of days needed to meet the task criterion was more in experimental groups I and II than that of control group. The results indicate that long-term exposure to EMF could impair WM function. The possible reason may be the impaired communication between different rhythmic oscillations caused by a decrease in θ-hγ PAC intensity. This paper demonstrates the negative effects of EMF on WM and reveals the potential neural mechanisms from the changes of PAC intensity, which provides important support for further investigation of the biological effects of EMF and its mechanisms.
    随着电气设备的广泛应用,长期处于50 Hz的电磁场(EMF)环境可能会使工作记忆(WM)等认知功能受到严重影响。然而,EMF影响WM的效应及其神经机制尚不明确。为此本文将15只大鼠随机分为三组,分别暴露于50 Hz、2 mT的EMF环境0 d(对照组)、24 d(实验Ⅰ组)和48 d(实验Ⅱ组),通过T-迷宫任务评估其WM水平,并基于在体多通道电生理记录系统获取内侧前额叶皮层(mPFC)的局部场电位(LFP),分析任务过程中θ和γ节律振荡的功率谱密度(PSD)变化,以及θ-γ节律的相位幅值耦合(PAC)强度变化。结果显示,实验Ⅰ组和Ⅱ组大鼠的θ和γ节律PSD均有不同程度下降,θ和高频γ(hγ)之间的PAC强度下降;实验Ⅰ组和Ⅱ组大鼠达到WM任务标准所需时长均高于对照组。结果表明EMF长期暴露损害了WM功能,可能的原因是θ-hγ的PAC强度下降引起的mPFC不同节律振荡之间的信息交流受损。本文从PAC强度变化的角度揭示了EMF对WM造成负面影响的潜在神经机制,为进一步探究EMF生物效应及其作用机制提供了重要支持。.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    探索电磁场(EMF)对功能性骨软骨组织构建的影响至关重要,骨软骨损伤的治疗具有一定的临床意义。目前,关于EMF方向对细胞的影响的研究很少。本研究旨在探讨EMF偶联对不同参数在2D水平和3D水平上控制脂肪干细胞(ADSCs)增殖和特异性软骨和成骨分化的影响。EMF诱导的ADSCs的增殖和分化受EMF和空间结构共同调控。在这项研究中,制备的Cs7/Gel3/nHAP支架具有良好的降解率(86.75±4.96%)和吸水性(1100%),孔径为195.63±54.72μm。获得了孔径为267.17±129.18μm的骨衍生支架,其主要成分为羟基磷灰石。Cs7/Gel3/nHAP支架和骨源支架适合作为3D级材料。最佳EMF强度为2mT用于软骨分化和增殖,1mT用于成骨分化和增殖。值得注意的是,在2D水平上,EMF与ADSCs在垂直方向上的增殖呈负相关,同时与3D水平的ADSCs增殖呈正相关。EMF介导的3D骨软骨支架为骨软骨组织工程构建提供了良好的策略。
    It is critical to explore the effects of electromagnetic field (EMF) on the construction of functional osteochondral tissue, which has shown certain clinical significance for the treatment of osteochondral injury. At present, there are few studies on the effect of the direction of EMF on cells. This study aimed to investigate the effects of EMF coupling on different parameters to control adipose-derived stem cells (ADSCs) proliferation and specific chondrogenic and osteogenic differentiation at 2D level and 3D level. The proliferation and differentiation of EMF-induced ADSCs are jointly regulated by EMF and space structure. In this study, Cs7/Gel3/nHAP scaffolds were prepared with good degradation rate (86.75 ± 4.96 %) and absorb water (1100 %), and the pore size was 195.63 ± 54.72 μm. The bone-derived scaffold with a pore size of 267.17 ± 129.18 μm was obtained and its main component was hydroxyapatite. Cs7/Gel3/nHAP scaffolds and bone-derived scaffolds are suitable as 3D level materials. The optimal EMF intensity was 2 mT for chondrogenic differentiation and proliferation and 1 mT for osteogenic differentiation and proliferation. It is noteworthy that EMF has a negative correlation with ADSCs proliferation in the vertical direction at 2D level, while it has a positive correlation with ADSCs proliferation at 3D level. EMF mediated 3D osteochondral scaffold provide good strategy for osteochondral tissue engineering construction.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    MXenes已被证明是先进的电磁干扰(EMI)屏蔽材料的出色损耗阶段。然而,它们对氧和水的耐受性差导致原始二维(2D)纳米结构的快速降解和功能性能的衰减。在这里,在这项研究中,天然抗氧化剂(例如,褪黑激素,茶多酚,和植酸)用于保护Ti3C2TxMXene免受其降解,以实现EMI屏蔽性能的长期稳定性。结果表明,由抗氧化剂和Ti3C2Tx组成的合成复合材料表现出减速的降解速率,从而改善了EMI屏蔽有效(SE)稳定性。关于Ti3C2TxMXene的纳米结构演变,讨论了所应用抗氧化剂的抗氧化机理。这项工作为进一步开发用于EM领域稳定应用的先进MXenes奠定了基础。
    MXenes have been proven to be outstanding lossy phase of advanced electromagnetic interference (EMI) shielding materials. However, their poor tolerance to oxygen and water results in fast degradation of the pristine two-dimensional (2D) nanostructure and fading of the functional performance. Herein, in this research, natural antioxidants (e.g., melatonin, tea polyphenols, and phytic acid) were employed to protect the Ti3C2Tx MXene from its degradation in order to achieve a long-term stability of the EMI shielding performance. The results showed that the synthesized composites comprised of antioxidants and Ti3C2Tx exhibited a decelerating degradation rate resulting in an improved EMI shielding effective (SE) stability. The antioxidation mechanism of the applied antioxidants is discussed with respect to the nanostructure evolution of the Ti3C2Tx MXene. This work contributes to the basic foundations for the further development of advanced MXenes for stable applications in the EM field.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    主动控制的纳升流体回路是电子学中迫切需要的技术,生物医学,化学合成,和生物传感。困难在于如何在玻璃晶片中以隔离和气密的方式驱动微流体。我们使用磁振荡泵来实现循环方向的切换和控制10nL流体的流量。二维数值模拟结果表明,流场可以达到稳定状态,可以获得稳定的流动。每个振动周期对流量的贡献与频率成正比,随粘度呈指数衰减,与振幅的4.2幂成比例,并且与半径成正比。与现有的流体技术相比,该技术首次在硬质材料中实现了小至10nL的全封闭磁控流体回路的转向和流量控制。
    Actively controlled nanoliter fluid circuits are an urgently needed technology in electronics, biomedicine, chemical synthesis, and biosensing. The difficulty lies in how to drive the microfluid in an isolated and airtight manner in glass wafer. We used a magnetic oscillator pump to realize the switching of the circulation direction and controlling the flow rate of the 10nL fluid. Results of two-dimensional numerical simulations shows that the flow field can reach a steady state and a stable flow can be obtained. The contribution of each vibration cycle to the flow rate is proportional to the frequency, decays exponentially with the viscosity, is proportional to the 4.2 power of the amplitude, and is proportional to the radius. Compared with the existing fluid technology, this technology realizes the steering and flow control of a fully enclosed magnetic control fluid circuit as small as 10nL in hard materials for the first time.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    在这项研究中,研究了具有不同电磁频率的螺线管结构的轴向电磁场处理装置(AEFTD)对管壳式换热器管侧碳酸钙(CaCO3)结晶污垢的影响。实验结果表明,AEFTD的应用可以有效降低污垢阻力,减缓CaCO3污垢的生长速度。结垢阻力与实验流体出口温度之间的相反趋势表明,应用AEFTD可以增强传热。同时,通过扫描电子显微镜(SEM)分析了污垢样品的晶体形貌。与方解石相反,轴向电磁场有利于球陨石的形成。非粘性球特石不易聚集成簇,并大量悬浮形成泥状污垢,可被湍流带走。此外,详细讨论了轴向电磁场的防污机理。在这项研究中,AEFTD对CaCO3污垢的防污作用表现出极端的特征。因此,AEFTD的有效性取决于电磁参数的选择。
    In this study, the influence of an axial-electromagnetic field treatment device (AEFTD) with a solenoid structure using different electromagnetic frequencies on calcium carbonate (CaCO3) crystallization fouling on the tube side of a shell-and-tube heat exchanger was investigated. The experimental results indicated that the application of the AEFTD could effectively reduce fouling resistance and decelerate the growth rate of CaCO3 fouling. The opposite trend between fouling resistance and the outlet temperature of an experimental fluid indicated that the application of the AEFTD could enhance heat transfer. Meanwhile, the crystal morphologies of the fouling samples were analyzed by means of scanning electron microscopy (SEM). The axial-electromagnetic field favored the formation of vaterite as opposed to calcite. Non-adhesive vaterite did not easily aggregate into clusters and was suspended in bulk to form muddy fouling that could be carried away by turbulent flow. Furthermore, the anti-fouling mechanism of the axial-electromagnetic field is discussed in detail. The anti-fouling effect of the AEFTD on CaCO3 fouling exhibited extreme characteristics in this study. Therefore, the effectiveness of the AEFTD is contingent upon the selection of the electromagnetic parameters.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

公众号