Imaging and spectral study on the null point of a fan-spine structure during a solar flare

Using the multi-instrument observations, we make the first simultaneous imaging and spectral study on the null point of a fan-spine magnetic topology during a solar flare. When magnetic reconnection occurs at the null point, the fan-spine configuration brightens in the (extreme-)ultraviolet channels. In the H$\alpha$ images, the fan-spine structure is partly filled and outlined by the bi-directional material flows ejected from the reconnection site. The extrapolated coronal magnetic field confirms the existence of the fan-spine topology. Before and after the flare peak, the total velocity of the outflows is estimated to be about 60 km s$^{-1}$. During the flare, the Si IV line profile at the reconnection region is enhanced both in the blue-wing and red-wing. At the flare peak time, the total velocity of the outflows is found to be 144 km s$^{-1}$. Superposed on the Si IV profile, there are several deep absorption lines with the blueshift of several tens of km s$^{-1}$. The reason is inferred to be that the bright reconnection region observed in Si IV channel is located under the cooler material appearing as dark features in the H$\alpha$ line. The blueshifted absorption lines indicate the movement of the cooler material toward the observer. The depth of the absorption lines also depends on the amount of cooler material. These results imply that this kind of spectral profiles can be used as a tool to diagnose the properties of cooler material above reconnection site.Comment: Accepted for publication in Ap

The Design of Tension Test Sensor and its Finite Element Analysis and Test Research

The tension test method of strip steel on stretching winding straightener tension roll group was elaborated. The material and paster form of resistance strain foil in tension test sensor were designed. The measure circuit of tension test sensor was designed. The material and structural form of elastic body of tension test sensor were designed. Strength computation was made on elastic body of tension test sensor. Three-dimensional entity model of elastic body of tension test sensor was built by SolidWorks software. Finite element analysis was made on relative model by ANSYS software. Relative stress figure and displacement figure of elastic body of tension test sensor were obtained. Tension test sensor was manufactured based on design. Static state compression rigidity test of elastic body of tension test sensor was made. Relative test system constitution, test method and test process were elaborated. Relative test data were disposed. This research provides reliable base for the design of tension test sensor

Observation of reentrant metal-insulator transition in a random-dimer disordered SSH lattice

The interrelationship between localization, quantum transport, and disorder has remained a fascinating focus in scientific research. Traditionally, it has been widely accepted in the physics community that in one-dimensional systems, as disorder increases, localization intensifies, triggering a metal-insulator transition. However, a recent theoretical investigation [Phys. Rev. Lett. 126, 106803] has revealed that the interplay between dimerization and disorder leads to a reentrant localization transition, constituting a remarkable theoretical advancement in the field. Here, we present the experimental observation of reentrant localization using an experimentally friendly model, a photonic SSH lattice with random-dimer disorder, achieved by incrementally adjusting synthetic potentials. In the presence of correlated on-site potentials, certain eigenstates exhibit extended behavior following the localization transition as the disorder continues to increase. We directly probe the wave function in disordered lattices by exciting specific lattice sites and recording the light distribution. This reentrant phenomenon is further verified by observing an anomalous peak in the normalized participation ratio. Our study enriches the understanding of transport in disordered mediums and accentuates the substantial potential of integrated photonics for the simulation of intricate condensed matter physics phenomena

The Design of Seamless Steel Tube Ultrasonic Flaw Detection System

In recent years, ultrasonic nondestructive detection technology has definite application in seamless steel tube flaw detection. Seamless steel tube ultrasonic flaw detection system was designed in this paper. The constitution and function of relative machine system, electron test system and electron control system were elaborated. Some ultrasonic echo circuits were designed. They are first rank damping circuit of first rank attenuator, second rank damping circuit of first rank attenuator, first rank damping circuit of second rank attenuator, first rank amplification circuit, second rank amplification circuit and restraint circuit respectively. The feasibility of above circuits has been proven by engineering application. The research provides important references base for designing seamless steel tube ultrasonic flaw detection system, enhancing test process reliability and increasing test efficiency

The Test System Design and Actual Test of Motor Axis Torque During Seamless Steel Tube Rolling

The gear break fault of reduction box was arisen often because of the motor axis torque amplification during seamless steel tube rolling. So, the motor axis of certain seamless steel tube factory was regarded as research object. The test system of motor axis torque during seamless steel tube rolling was designed. Test position was confirmed. Strain foils, torque track 9000 digital telemetry system and vision digital record device were adopted on the actual test of motor axis torque during seamless steel tube rolling. The strain oscillograms and relative compute results during rolling from the first steel tube to the ninth steel tube were obtained. The full range torque compute formula during actual test was obtained. The actual output torque compute formula was obtained. The relative actual output of mean torque and maximum torque was obtained. The research provides important references base for real time motor axis torque test and effective gear break fault prevention of reduction box during seamless steel tube rolling