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161.
We present preparation of asymmetric grating with higher diffraction efficiency in quantum dot molecules by combining the tunneling effect and parity-time antisymmetry.In the presence of tunneling between two quantum dots,the system exhibits the striking PT antisymmetry via spatially modulating the driving field and the detuning with respect to the driven transition.For this reason,the asymmetric grating could be achieved.The results show that the diffraction efficiency can be adjustable via changing the driving intensity,detuning,tunneling strength,and interaction length,and then the high-order diffraction can be reached.The scheme provides a feasible way to obtain the direction-controlled diffraction grating,which can be helpful for optical information processing and realization of controllable optical self-image. 相似文献
162.
Hai-Xiao Zhang 《中国物理 B》2022,31(12):124301-124301
The explorations of parity-time ($\mathcal{PT}$)-symmetric acoustics have resided at the frontier in physics, and the pre-existing accessing of exceptional points typically depends on Fabry-Perot resonances of the coupling interlayer sandwiched between balanced gain and loss components. Nevertheless, the concise $\mathcal{PT}$-symmetric acoustic heterostructure, eliminating extra interactions caused by the interlayer, has not been researched in depth. Here we derive the generalized unitary relation for one-dimensional (1D) $\mathcal{PT}$-symmetric heterostructure of arbitrary complexity, and demonstrate four disparate patterns of anisotropic transmission resonances (ATRs) accompanied by corresponding spontaneous phase transitions. As a special case of ATR, the occasional bidirectional transmission resonance reconsolidates the ATR frequencies that split when waves incident from opposite directions, whose spatial profiles distinguish from a unitary structure. The derived theoretical relation can serve as a predominant signature for the presence of $\mathcal{PT}$ symmetry and $\mathcal{PT}$-symmetry-breaking transition, which may provide substantial support for the development of prototype devices with asymmetric acoustic responses. 相似文献
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介绍了以C8051F020单片机为主要控制芯片,同时采用编解码芯片组PT2262/PT2272,配以射频发射、接收模块实现脉搏测试仪的无线遥控。 相似文献
165.
Nawal Mecherout Naima Boussekkine Thierry Ramond Johannes Sjöstrand 《Mathematische Nachrichten》2016,289(7):854-887
We study a class of ‐symmetric semiclassical Schrödinger operators, which are perturbations of a selfadjoint one. Here, we treat the case where the unperturbed operator has a double‐well potential. In the simple well case, two of the authors have proved in 6 that, when the potential is analytic, the eigenvalues stay real for a perturbation of size . We show here, in the double‐well case, that the eigenvalues stay real only for exponentially small perturbations, then bifurcate into the complex domain when the perturbation increases and we get precise asymptotic expansions. The proof uses complex WKB‐analysis, leading to a fairly explicit quantization condition. 相似文献
166.
Proficiency testing (PT) results have been used to improve traceability in chemical drinking water analysis. With a generalized
least-square regression the mass concentrations of As and Sb were calculated in a drinking water that had been used to prepare
proficiency testing samples by a spiking procedure. From the mass concentrations in the matrix and the spiked amounts, reference
values with an uncertainty budget could be calculated without the need for reference measurements. The degree to which these
reference values can be regarded as traceable is discussed. The results showed slight deviations in some samples between reference
values and consensus means. 相似文献
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G. Singh I. Bhaumik S. Ganesamoorthy A. K. Karnal V. S. Tiwari 《Crystal Research and Technology》2007,42(4):378-383
Domain structure and phase transition sequence of 0.91PZN‐0.09PT single crystal, grown from high temperature solution, have been analysed using polarised light microscopy. The domain structure of (001)cub cut single crystal exhibit co‐existence of rhombohedral and tetragonal phases. The sequence and phase transition temperatures have been determined from temperature dependence of birefringence. Birefringence measurements during heating and cooling reveal a first order nature of phase transition between rhombohedral (R3m) and tetragonal (P4mm). The birefringence was measured with accuracy of 10‐3. However, dielectric measurement does not provide any evidence of R3m ‐ P4mm phase transition. It is shown that in‐situ analysis of domain structure and phase transition can be used as non‐destructive analytical tool for determination of local composition and phase transition sequence. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献