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1.
《中国物理 B》2021,30(6):60314-060314
Besides its fundamental importance, non-reciprocity has also found many potential applications in quantum technology. Recently, many quantum systems have been proposed to realize non-reciprocity, but stable non-reciprocal process is still experimentally difficult in general, due to the needed cyclical interactions in artificial systems or operational difficulties in solid state materials. Here, we propose a new kind of interaction induced non-reciprocal operation, based on the conventional stimulated-Raman-adiabatic-passage(STIRAP) setup, which removes the experimental difficulty of requiring cyclical interaction, and thus it is directly implementable in various quantum systems. Furthermore, we also illustrate our proposal on a chain of three coupled superconducting transmons, which can lead to a non-reciprocal circulator with high fidelity without a ring coupling configuration as in the previous schemes or implementations. Therefore, our protocol provides a promising way to explore fundamental non-reciprocal quantum physics as well as realize non-reciprocal quantum device. 相似文献
2.
Screw rotors play a crucial role in the performance of compressors. For the large-batch production of small- or medium-sized rotors, continuously rotor hobbing or grinding may be more efficient than form machining. In this study, a general mathematical model was developed for the generating machining of screw rotors with a worm-shaped tool. A two-parameter enveloping theory was applied to simulate the cutting process as the tool conducts polynomial feed motion considering its cutting edge. The normal errors of the generated cutting lines were computed and presented on the rotor tooth surface topologies to show the correctness and practicability of the proposed model. 相似文献
3.
Prof. Dr. Mingoo Jin Satsuki Matsuura Hikaru Yamamoto Prof. Dr. Motohiro Mizuno Prof. Dr. Hajime Ito 《European journal of organic chemistry》2023,26(12):e202201468
We report multidynamic molecular rotations in crystals using a concave-shape N-heterocyclic carbene (NHC) binuclear Au(I) complex rotor bearing pyrazine and tetrahydrofuran (THF) molecules as multicomponent rotators. Single-crystal X-ray diffraction (XRD) measurements revealed that two THF molecules are located near the central pyrazine encapsulated by two bulky NHC ligands. From 2H solid-state NMR analysis, it was observed that the pyrazine rotated in a 2-fold site exchange with a 180° rotational angle and a 31 kJ mol−1 energy barrier, while the THF molecules showed a 23°-38° libration with a lower energy barrier (14 kJ mol−1). Interestingly, the pyrazine rotation was accelerated when the THF molecules rotated in fast site exchange with a large angle of libration, suggesting that the rotators exhibit multidynamics in a correlated manner. 相似文献
4.
High‐temperature superconductivity and long‐range order in strongly correlated electronic systems 下载免费PDF全文
Lawrence J. Dunne 《International journal of quantum chemistry》2015,115(20):1443-1458
A selective review of the question of how repulsive electron correlations might give rise to off‐diagonal long‐range order (ODLRO) in high‐temperature superconductors is presented. The article makes detailed explanations of the relevance to superconductivity of reduced electronic density matrices and how these can be used to understand whether ODLRO might arise from Coulombic repulsions in strongly correlated electronic systems. Time‐reversed electron pairs on alternant Cuprate and the iron‐based pnictide and chalcogenide lattices may have a weak long‐range attractive tail and much stronger short‐range repulsive Coulomb interaction. The long‐range attractive tail may find its origin in one of the many suggested proposals for high‐Tc superconductivity and thus has an uncertain origin. A phenomenological Hamiltonian is invoked whose model parameters are obtained by fitting to experimental data. A detailed summary is given of the arguments that such interacting electrons can cooperate to produce a superconducting state in which time‐reversed pairs of electrons effectively avoid the repulsive hard‐core of the Coulomb interaction but reside on average in the attractive well of the long‐range potential. Thus, the pairing of electrons itself provides an enhanced screening mechanism. The alternant lattice structure is the key to achieving robust high‐temperature superconductivity with dx2‐y2 or sign alternating s‐wave or s± condensate symmetries in cuprates and iron‐based compounds. Some attention is also given to the question first raised by Leggett as to where the Coulombic energy is saved in the superconducting transition in cuprates. A mean‐field‐type model in which the condensate density serves as an order parameter is discussed. Many of the observed trends in the thermal properties of cuprate superconductors are reproduced giving strong support for the proposed model for high‐temperature superconductivity in such strongly correlated electronic systems. © 2015 Wiley Periodicals, Inc. 相似文献
5.
旋翼尾流与地面干扰时地面涡现象的研究 总被引:1,自引:0,他引:1
用N-S方程对近地飞行时旋翼尾流与地面干扰时产生的地面涡现象进行了数值计算旋翼对流场的作用由分布在特定区域内的动量源项模拟结果表明,旋翼尾流撞到地面后的卷起和轴向流动的拉伸作用是形成地面涡的原因;地面边界层形成的二次分离涡向地面涡内输入(与尾流所携带的涡量)相反的涡量,而使地面涡保持平衡;地面涡的存在和运动使旋翼附近流场大大改变 相似文献
6.
7.
Effect of parameters on the rubbing condition of an unbalanced rotor system with initial permanent deflection 总被引:1,自引:0,他引:1
Xiaoyao Shen Jiuhong Jia Mei Zhao 《Archive of Applied Mechanics (Ingenieur Archiv)》2007,77(12):883-892
A rotor-stator rubbing Jeffcott model of a rotor system with mass unbalance including the mass eccentricity and the initial
permanent deflection was set up and the corresponding governing motion equation was derived by d’Alembert principle. Through
the analytical method, the rubbing condition was analyzed. Whether the rub would happen and when the rub would happen were
well solved. The amplitude of the rotor center was calculated, and the rubbing factor was introduced to determine whether
the rub would happen or not for all rotating speeds. Rubbing speeds when rub began to happen were obtained. Parameters such
as the mass eccentricity, the initial permanent deflection, damping coefficients, and the phase angle between the mass eccentricity
and the permanent deflection were used to analyze their effect on the rubbing condition. Results were obtained and could be
used to prevent the rubbing fault or decrease the damage of the rub and diagnose or balance the initial permanent deflection
fault. 相似文献
8.
HT-7U托克马克装置的纵场线圈是由多种材料组成的具有周期性分布的大型复杂结构,线圈可视为由超导线、支撑结构和绝缘材料组成的复合材料,结构极其复杂。整个线圈工作在液氦温区。在设计阶段对其宏观等效力学性能进行数值分析计算是十分必要的,但要对整个线圈直接进行有限元分析或实验是极其困难的,主要利用均匀化方法对其进行等效处理,从而分析计算其宏观等效模量,为线圈的设计和评估提供参考依据。另外本文对均匀化方法的边界条件进行了一些改进,提出了更加合理的三维边界条件。 相似文献
9.
10.
利用积分变换法导出了蒸汽温升率连续变化时汽轮机转子的温度场和热应力场计算公式。本公式可直接应用于转子的应力监测与控制。和差分法相比,解析法的数据处理速度快,能满足快速监测、及时跟踪与控制的要求。关键词:汽轮机转子;温度场;热应力场 相似文献