Hanle detection for optical clocks

Considering the strong inhomogeneous spatial polarization and intensity distribution of spontaneous decay fluorescence due to the Hanle effect, we propose and demonstrate a universe Hanle detection configuration of electron-shelving method for optical clocks. Experimental results from Ca atomic beam optical frequency standard with 423 nm electron-shelving method show that a designed Hanle detection geometry with optimized magnetic field direction, detection laser beam propagation and polarization direction, and detector position can improve the fluorescence collection rate by more than one order of magnitude comparing with that of inefficient geometry. With the fixed 423 nm fluorescence, the improved 657 nm optical frequency standard signal intensity is presented. And the potential application of the Hanle detection geometry designed for facilitating the fluorescence collection for optical lattice clock with a limited solid angle of the fluorescence collection has been discussed. This Hanle detection configuration is also effective for ion detection in ion optical clock and quantum information experiments. Besides, a cylinder fluorescence collection structure is designed to increase the solid angle of the fluorescence collection in Ca atomic beam optical frequency standard.Comment: 5 pages, 6 figure

Shuttle-like supramolecular nanostructures formed by self-assembly of a porphyrin via an oil/water system

In this paper, in terms of the concentration of an aqueous solution of a surfactant, we investigate the self-assembly behavior of a porphyrin, 5, 10, 15, 20-tetra(4-pyridyl)-21H, 23H-porphine [H2TPyP], by using an oil/water system as the medium. We find that when a chloroform solution of H2TPyP is dropwise added into an aqueous solution of cetyltrimethylammonium bromide [CTAB] with a lower concentration, a large amount of irregular nanoarchitectures, together with a small amount of well-defined shuttle-like nanostructures, hollow nanospheres, and nanotubes, could be produced. While a moderate amount of shuttle-like nanostructures accompanied by a few irregular nanoarchitectures, solid nanospheres, and nanorods are produced when a CTAB aqueous solution in moderate concentration is employed, in contrast, a great quantity of shuttle-like nanostructures together with a negligible amount of solid nanospheres, nanofibers, and irregular nanostructures are manufactured when a high-concentration CTAB aqueous solution is involved. An explanation on the basis of the molecular geometry of H2TPyP and in terms of the intermolecular π-π interactions between H2TPyP units, and hydrophobic interactions between CTAB and H2TPyP has been proposed. The investigation gives deep insights into the self-assembly behavior of porphyrins in an oil/water system and provides important clues concerning the design of appropriate porphyrins when related subjects are addressed. Our investigation suggests that an oil/aqueous system might be an efficient medium for producing unique organic-based nanostructures

Research on Ecological Assessment and Dynamic Optimization of Energy-saving and New Energy Vehicle Business Model Based on Full Life Cycle Theory

The rapid development of China's automobile industry has brought ever-increasing impact on resources, energy and environment, the energy-saving and new energy vehicles come into being accordingly. This article firstly systematically introduces the technical route of energy-saving and new energy vehicles of China, focusing on the key bottleneck problems arising from  the construction process of current assessment system of the technical route for energy-saving and new energy vehicles, establishes the energy-saving and new energy vehicle business model assessment index system afterward based on the comparative analysis on energy-saving and new energy vehicle business assessment model and the full life cycle theory, and finally makes prospects and forecasts on vital problems of system boundary, dynamic optimization, simulation system of full life cycle assessment of energy-saving and new energy vehicle

Asynchronous vibration response characteristics of connectors with looseness fault and its verification

For the universal phenomenon of the aero-engine connectors with the looseness fault, a single degree of freedom lumped mass model was established and a looseness fault model was introduced. The response of the system was obtained by numerical integration methods and the asynchronous response characteristics were analyzed. The experiments were conducted on the connectors with looseness clearance. It is found that the acceleration response of the mass block after noise reduction has up-down asymmetrical impact characteristics in the waveform, also the pseudo-critical subharmonic resonance and the pseudo-critical ultra-harmonic resonance appear in frequency spectrum. These characteristics are in agreement with the results of the numerical simulation, which can be identified as the characteristics of the looseness fault. The reason leading to the looseness characteristics is that the period of stiffness changes in the period of the rotating speed. When the changing period of stiffness is equivalent to the vibration period, frequency multiplication will appear and the natural frequency of the system will be excited at specific speeds. When the changing period of stiffness is equivalent to n times the vibration period, 1/n frequency division and frequency multiplication will appear and the natural frequency of the system will be excited at specific speeds