关键词： THz antenna   multi-beam   graphene   dual-band   reconfigurable  

摘要： In this paper,a dual-band graphene-based frequency selective surface(GFSS)is investigated and the operating mechanism of this GFSS is *** adjusting the bias voltage to control the graphene chemical po-tential between 0 eV and 0.5 eV,the GFSS can achieve four working states:dual-band passband,high-pass lowimpedance,low-pass high-impedance,and *** on this GFSS,a hexagonal radome on a broadband omnidirectional monopole antenna is proposed,which can achieve independent 360°six-beam omnidirectional scanning at 1.08 THz and 1.58 THz dual *** addition,while increasing the directionality,the peak gains of the dual bands reach 7.44 dBi and 6.67 dBi,*** work provides a simple method for realizing multi-band terahertz multi-beam reconfigurable antennas.

关键词： 石墨烯   离子辐照   界面热导   晶格结构   吸附作用  

摘要： 作为一种二维材料,石墨烯因其超高的导热系数而被广泛研究,特别是在电子器件散热领域。然而,石墨烯界面的低热导限制了石墨烯在散热领域中应用。为了提高石墨烯界面的热传导效率,文章通过聚焦镓离子束对石墨烯进行离子辐照,研究了离子辐照能量对石墨烯界面热输运的影响。实验测量结果显示,随着离子辐照能量的增加,Al/graphene/SiO2的界面热导呈现上升的趋势,并且在30 kV能量下升高了近3倍。实验表征及理论计算结果显示,镓离子辐照破坏了石墨烯原有的晶格结构,导致离子辐照石墨烯表面上的C/O化学官能团发生了重构,提高了铝膜与离子辐照石墨烯之间界面的吸附作用,进而增加了界面上的声子透射率,最终提升了Al/graphene/SiO2的界面热导。As a two-dimensional material, graphene has been widely studied for its ultra-high thermal conductivity, especially in the field of electronic device cooling. However, the high thermal resistance at the graphene interface limits the application of graphene in the field of heat dissipation. In order to improve the heat conduction efficiency of graphene interface, the effects of energy of ion irradiation on the thermal transport across the graphene interface are investigated in this paper after graphene irradiated by focusing gallium ion beams. It is demonstrated that the interfacial thermal conductance of Al/graphene/SiO2 shows an upward trend with increasing energy and increases up to nearly 3 times at the energy of 30 kV. The experimental characterization and theoretical calculation results show that Ga ion irradiation destroys the original lattice structure of graphene, leading to the reconstruction of C/O chemical functional groups on the ion-irradiated graphene surface, which intensifies the adsorption strength between Al film and ion-irradiated graphene. The increased interfacial adsorption strength is beneficial to more phonons being able to transport across the interface, and finally leads to the increased thermal conductance of Al/graphene/SiO2.

关键词： 氧化石墨烯   光学性质   电子结构   密度泛函理论  

摘要： 为了研究不同位置O原子对氧化石墨烯(GO)性能的影响,基于密度泛函理论(DFT),模拟计算了3种氧原子吸附位对GO的电子结构和光学性质的影响。结果表明,在加入O原子之后,石墨烯的电子性质主要受O原子2p轨道的影响,3种不同吸附位置O原子的氧化石墨烯的光学性质也有差别,O原子吸附于石墨烯C—C键上的GO在波长为300~600 nm可见光表现出良好的光吸收性能,O原子吸附于碳六元环空位及石墨烯边缘的GO在可见光波长大于600 nm至近红外范围的光吸收性能更好。

关键词： Ultra-thin BN   Fe doping   BN-Fe-graphene   Mild polarization electric field   Nitrogen reduction reaction  

摘要： The electrocatalytic N_(2)reduction reaction(NRR)is expected to supersede the traditional Haber-Bosch technology for NH3 production under ambient *** activity and selectivity of electrochemical NRR are restricted to a strong polarized electric field induced by the catalyst,correct electron transfer direction,and electron tunneling distance between bare electrode and active *** coupling the chemical vapor deposition method with the poly(methyl methacylate)-transfer method,an ultrathin sandwich catalyst,i.e.,Fe atoms(polarized electric field layer)sandwiched between ultrathin(within electron tunneling distance)BN(catalyst layer)and graphene film(conducting layer),is fabricated for electrocatalytic *** sandwich catalyst not only controls the transfer of electrons to the BN surface in the correct direction under applied voltage but also suppresses hydrogen evolution reaction by constructing a neutral polarization electric field without metal *** sandwich electrocatalyst NRR system achieve NH3 yield of 8.9μg h^(−1)cm^(−2)and Faradaic Efficiency of 21.7%.The N_(2)adsorption,activation,and polarization electric field changes of three sandwich catalysts(BN-Fe-G,BN-Fe-BN,and G-Fe-G)during the electrocatalytic NRR are investigated by experiments and density functional theory *** by applied voltage,the neutral polarized electric field induced by BN-Fe-G leads to the high activity of electrocatalytic NRR.

关键词： Single-molecule switch   Spin filtering effect   Odd-even effect   Nonequilibrium Green's function method   Density functional theory  

摘要： Moleculardeviceswith highswitchingperformance and/or the perfect spin filtering effect have always been the pursuit with the development of molecular ***,yusingthe 2001.0V ***'s function method in combination with the density functionaltheory,the switching performance and spin filtering properties of dimethyldihydropyrene(DHP)/cyclophanediene(CPD)photoswitchable molecule connected by carbon atomic chains(CACs)to two zigzag graphene nanoribbon electrodes have been theoretically *** results show that DHP is more conductive than CPD and therefore an evident switching effect is demonstrated,and the switching ratio(RON/OFF)can reach 4.5×*** is further revealed that the RoON/OF of DHP/CPD closely depends on the length of *** specifically,the RoN/OFF values of DHP/CPD with odd-numbered CACs are larger than those with even-numbered *** interestingly,a high or even perfect spin filtering effect can be obtained in these investigated DHP/CPD single-molecule *** study is helpful for future design of single-molecule switches and spin filters and provides a way to optimize their performance by means of varying the length of bridging CACs.

关键词： 铜基复合材料   碳纳米管   石墨烯   导电性   力学性能   微观结构  

摘要： 本文回顾了碳纳米管(CNT)和石墨烯(Gr)增强铜基复合材料的研究进展,探讨了这些复合材料的制备方法、性能提升机制及潜在应用前景。CNT和Gr因独特的物理化学特性,作为铜基复合材料的理想增强相,显著提升了材料的力学性能、导电性和热导率。首先回顾了铜基复合材料的传统制备技术,包括粉末冶金法和机械合金化法,随后介绍了新兴的化学气相沉积(CVD)和电沉积法,这些技术通过直接生长或电化学沉积实现更好的界面结合。对比分析了不同方法的优缺点,指出粉末冶金和机械合金化的成本较低但可能引起增强相分布不均,而CVD法虽能制备高质量材料但成本较高且环境影响敏感。进一步分析了CNT和Gr在铜基体中的分散性及界面结合对性能的影响,强调了良好分散性和强界面结合的重要性。在力学性能方面,CNT和Gr的分散性和界面结合对复合材料的强化机制起着关键作用,包括载荷转移、晶粒细化和Orowan强化等。此外,讨论了CNT和Gr增强铜基复合材料在耐腐蚀性、磨损性能及热管理等方面的应用潜力。尽管存在挑战,但这些复合材料在电力传输、电子器件和航空航天等领域显示出巨大应用前景。未来的研究将集中于微观结构控制、制备工艺创新和多功能复合材料开发,以实现更高性能的工业应用。

关键词： 石墨烯热声发声器   BP神经网络   GA遗传算法   声压级  

摘要： 为了解决传统石墨烯发声器物理模型计算量大、精度不高的问题,提出了一种基于GA遗传算法的BP神经网络模型,该算法模型具有更高的精度和适应性。首先,介绍了石墨烯热声发声原理以及实验设计,建立了GA-BP神经网络模型。其次,对模型的参数进行了调节,并对比了基于dropout、基于正则化、基于正则化和GA遗传算法的三种神经网络模型。随后在模型中输入石墨烯发声器的正弦激励幅值、频率以及测量距离,使用GA遗传算法对隐藏层的权值和偏置进行全局寻优,将寻优结果代入BP神经网络,最终预测出给定条件下的声压级。结果表明,在均使用正则化的条件下,BP神经网络预测准确度为98.05%,均方差为0.23;GA-BP神经网络预测准确度达到98.62%,均方差仅为0.14。优化后精准度提高了0.57%,均方差降低了41.36%,展现出更加优异的准确性和适应性。该研究为预测多类特征传感器的非线性输出结果提供了一种高精准度、高适应性的方案。

关键词： 石墨烯   硫化钴钼   超级电容器  

摘要： 石墨烯负载的Co-Mo-S复合材料(Co-Mo-S/G)作为超级电容器的电极材料具有巨大的发展潜力。本研究采用简单的水热法制备了Co-Mo-S复合材料,并对所制得的Co-Mo-S/G复合材料的形貌结构和电学性能进行了分析。结果表明,硫化钴钼粒子均匀地分布在石墨烯片层上,材料的比表面积为140.793 m 2/g,较大的比表面积有利于电解液离子和活性位点间的接触,从而增加电极材料的电学性能;在电流密度为1 A/g时,Co-Mo-S/G复合材料的比电容为1162 F/g,远高于单金属复合材料Co-S/G和Mo-S/G的比电容量。

关键词： Cu-BTC   三维网状石墨烯   染料敏化太阳能电池   光阳极  

摘要： 采用Cu-BTC和三维网状石墨烯(3DGNs)对光阳极材料进行改性,通过提高光阳极的比表面积以及提供光生电子的快速输运通道,器件的短路电流和光电转换效率实现了显著的提高。采用SEM和XRD对复合光阳极的微结构进行分析,通过电流-电压曲线和入射光电流转化效率分析其光伏特性。通过调整光阳极中Cu-BTC,3DGNs和TiO 2的质量分数实现各种组分的协同作用。优化后,器件的短路电流为(20.5±0.1)mA/cm^(2),开路电压为(680±2)mV,填充因子为(61.9±0.1)%,能量转换效率为(8.63±0.1)%。

关键词： 硅烷偶联剂   纳米炭黑   聚二甲基硅氧烷   电磁屏蔽   石墨烯   屏蔽效果   屏蔽材料   方法和应用  

摘要： 申请公布号(CN 112322041 A)提供了一种电磁屏蔽橡胶及其制备方法和应用。该电磁屏蔽橡胶的原料组成包括以下组分:二羟基聚二甲基硅氧烷30~55份、填料26~45份、纳米炭黑5~10份、石墨烯0.6~1.2份、硅烷偶联剂0.05~0.15份、屏蔽材料201E 0.05~3份、固化剂0.5~2.5份。本发明还提供了上述电磁屏蔽橡胶的制备方法。本发明的电磁屏蔽橡胶的原料成本低、屏蔽效果优异。