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1.
As one of the most attractive non-radiative power transfer mechanisms without cables,efficient magnetic resonance wireless power transfer(WPT)in the near field has been extensively developed in recent years,and promoted a variety of practical applications,such as mobile phones,medical implant devices and electric vehicles.However,the physical mechanism behind some key limitations of the resonance WPT,such as frequency splitting and size-dependent efficiency,is not very clear under the widely used circuit model.Here,we review the recently developed efficient and stable resonance WPT based on non-Hermitian physics,which starts from a completely different avenue(utilizing loss and gain)to introduce novel functionalities to the resonance WPT.From the perspective of non-Hermitian photonics,the coherent and incoherent effects compete and coexist in the WPT system,and the weak stable of energy transfer mainly comes from the broken phase associated with the phase transition of parity-time symmetry.Based on this basic physical framework,some optimization schemes are proposed,including using nonlinear effect,using bound states in the continuum,or resorting to the system with high-order parity-time symmetry.Moreover,the combination of non-Hermitian physics and topological photonics in multi-coil system also provides a versatile platform for long-range robust WPT with topological protection.Therefore,the non-Hermitian physics can not only exactly predict the main results of current WPT systems,but also provide new ways to solve the difficulties of previous designs.  相似文献   
2.
级间加气是乙烯工业节能增产的重要手段,特别是百万吨乙烯压缩机加气量高达8倍于上游通流流量,对下游叶轮气动匹配及整机性能影响巨大。目前关于压缩机加气特性及与通流相互影响的研究鲜有报道。本文基于计算流体动力学方法,建立了通流部件与径向加气室内部流动的耦合模型,并以百万吨乙烯压缩机为研究对象,通过分析上一级通流特性、通流-加气侧流耦合特性、通流为射流的加气侧流特性,研究通流与侧流相互作用机理。结果表明:通流性能曲线的流动计算结果与压缩机选型程序结果吻合较好;侧流流量远高于通流流量时,通流为射流的加气侧流模型可替代复杂耗时的通流-侧流耦合模型。研究工作为压缩机级间加气的设计优化提供了快速准确的流动计算模型。  相似文献   
3.
Zhengran Wang 《中国物理 B》2022,31(4):48202-048202
Excited-state double proton transfer (ESDPT) in the 1-[(2-hydroxy-3-methoxy-benzylidene)-hydrazonomethyl]-naphthalen-2-ol (HYDRAVH2) ligand was studied by the density functional theory and time-dependent density functional theory method. The analysis of frontier molecular orbitals, infrared spectra, and non-covalent interactions have cross-validated that the asymmetric structure has an influence on the proton transfer, which makes the proton transfer ability of the two hydrogen protons different. The potential energy surfaces in both S0 and S1 states were scanned with varying O-H bond lengths. The results of potential energy surface analysis adequately proved that the HYDRAVH2 can undergo the ESDPT process in the S1 state and the double proton transfer process is a stepwise proton transfer mechanism. Our work can pave the way towards the design and synthesis of new molecules.  相似文献   
4.
“线段、射线、直线”是《义务教育数学课程标准(2011年版)》中“图形与几何”板块最基本的概念之一.本文采用内容分析法对人教版与北师大版“线段、直线、射线”及其相关内容进行了分析.  相似文献   
5.
Shortening the distance between the depletion region and the electrodes to reduce the trapped probability of carriers is a useful approach for improving the performance of heterojunction.The CdS/Si nanofilm heterojunctions are fabricated by using the radio frequency magnetron sputtering method to deposit the amorphous silicon nanofilms and Cd S nanofilms on the ITO glass in turn.The relation of current density to applied voltage(I-V)shows the obvious rectification effect.From the analysis of the double logarithm I-V curve it follows that below~2.73 V the electron behaviors obey the Ohmic mechanism and above~2.73 V the electron behaviors conform to the space charge limited current(SCLC)mechanism.In the SCLC region part of the traps between the Fermi level and conduction band are occupied,and with the increase of voltage most of the traps are occupied.It is believed that Cd S/Si nanofilm heterojunction is a potential candidate in the field of nano electronic and optoelectronic devices by optimizing its fabricating procedure.  相似文献   
6.
二硫化钼纳米带按边界结构特征可分为锯齿型和扶手型,在制备过程中,不可避免地会存在一定的缺陷,其中硫空位(VS)最为常见,它将改变纳米结构,进而影响其电子性质。本文采用密度泛函理论来研究S空位对扶手型二硫化钼纳米带性质的影响。计算结果表明:纯扶手型二硫化钼纳米带(AMoS2NRs)为非磁性半导体,但其物性受S空位的位置及浓度所调制。当S空位出现在纳米带内部时,其性质不变。但当S空位在纳米带边缘时,AMoS2NRs被调节成半金属;并随着S空位的浓度的增加,其物性从半金属转变为稀磁半导体。这一有趣的发现将使得低维MoS2纳米材料在自旋电子学上有更宽广的应用。  相似文献   
7.
Guang-Tong Zhou 《中国物理 B》2022,31(6):68103-068103
The synergistic influences of boron, oxygen, and titanium on growing large single-crystal diamonds are studied using different concentrations of B2O3 in a solvent-carbon system under 5.5 GPa-5.7 GPa and 1300 ℃-1500 ℃. It is found that the boron atoms are difficult to enter into the crystal when boron and oxygen impurities are doped using B2O3 without the addition of Ti atoms. However, high boron content is achieved in the doped diamonds that were synthesized with the addition of Ti. Additionally, boron-oxygen complexes are found on the surface of the crystal, and oxygen-related impurities appear in the crystal interior when Ti atoms are added into the FeNi-C system. The results show that the introduction of Ti atoms into the synthesis cavity can effectively control the number of boron atoms and the number of oxygen atoms in the crystal. This has important scientific significance not only for understanding the synergistic influence of boron, oxygen, and titanium atoms on the growth of diamond in the earth, but also for preparing the high-concentration boron or oxygen containing semiconductor diamond technologies.  相似文献   
8.
New experimental cross-section data for the180 W(n,2 n)179 mW,186 W(n,2 n)185 mW and186 W(n,p)186 Ta reactions at the neutron energies of 13.5 and 14.4 MeV are obtained by the activation technique. The neutron beams are produced by means of the3 H(d,n)4 He reaction. The gamma activities of the product nuclei are measured by a high-resolution gamma-ray spectrometer with a coaxial high-purity germanium detector. The neutron fluence is determined using the monitor reaction93 Nb(n,2 n)92 mNb. The results in the current work are discussed and compared with the measurement results found in the literature. It is shown that these higher accuracy experimental cross-section data around the neutron energy of 14 MeV agree with some previous experimental values from the literature within experimental uncertainties.  相似文献   
9.
合成出了1个新的苯并咪唑-酰腙衍生物,N'-(2-羟基-1-萘基)亚甲基-2-[2-(4-甲基苯磺酰基甲基)-1H-苯并咪唑-1-基]乙酰肼(L),并利用IR,~1H NMR,~(13)C NMR,HRMS和元素分析对其结构进行了表征.利用裸眼、紫外-可见与荧光光谱研究了L对阴离子的识别性能.研究结果表明,向化合物L的CH_3CN溶液中加入F~-,Ac O~-和H _2PO_4~-后,溶液由无色变为亮黄色.在紫外灯下(λ=365 nm),加入F~-和AcO~-后,L的溶液发射出黄色荧光.表明化合物L可作为裸眼识别F~-,AcO~-和H_2PO_4~-的探针.紫外和荧光光谱实验结果显示,探针L可高选择性和高灵敏性识别F~-和AcO~-.探针L与F~-和AcO~-的结合常数(K_a)分别为4.25×10~3和2.96×10~4 L·mol~(-1),检出限(DL)分别为3.63×10~(-7)和8.51×10~(-8) mol·L~(-1).Job曲线和密度泛函理论(DFT)计算证明,探针L与F~-/AcO~-是1∶1配位.通过~1H NMR滴定确定了探针L与F~-/Ac O~-的络合机理.实验结果表明,化合物L可作为检测F~-和AcO~-的比色和荧光探针.  相似文献   
10.
针对工业实际项目提出一种高效、准确的二维码识别方法,并开发了基于机器视觉的二维码高速、批量识别系统。首先根据被测二维码在目标子空间内的位置,提出利用几何关系定位每个二维码感兴趣区域并批量处理二维码的方法。在此基础上,采用添加高斯噪声的方式模拟生产实际中可能产生的噪声,评估系统抗噪能力。最后分析系统识别率与二维码运动速度的关系并比较实验结果。通过实验验证,在1800张的测试数据集中,二维码移动速度在296.8 mm/s情况下,无噪声图像中每个二维码定位识别平均时间为17.8 ms,有噪声图像为21.3 ms,识别率均为100%,该系统满足实时在线检测需求。  相似文献   
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