Narrow Results

In nature, living organisms move in a collective state of aggregation, this collective motion is influenced by the nature of the environment, the obstacles refocused during the movement and the local interaction between individuals, this interaction is responsible for avoiding collision between each individual. In this paper, we study numerically the collective motion of self-organized organisms by expanding the Langevin dynamics, in which we have modeled the interaction between individuals by an elastic force. Modeling the interaction between individuals using an elastic force gives remarkable results. This interaction has an important effect if the individuals are dispersed a lot in space, but if a certain number of particles N is exceeded, this force is of no importance and the saturation velocity becomes constant. The results of the numerical simulation show that the average velocity of the individuals goes through a transient regime before reaching the permanent regime. Moreover, the results show that the system represents a transition from a nonequilibrium state to an equilibrium state, which is similar to a second-phase transition (paramagnetic/ferromagnetic) in the absence of the magnetic field; this phase transition is observable if the distance between two individuals is greater than a critical radius noted $R_c$.

The mechanical property is one of the important parameters for evaluating micro/nano-scale materials. The measurement of micro/nano-mechanical property usually involves measurements of small displacement and force. To provide a traceable force standard in micro/nano-newton level, we have developed a force measurement system based on electrostatic sensing and actuation techniques. The system mainly consists of a monolithic flexure stage, a three-electrode capacitor and a digital controller. The three-electrode capacitor is utilized as a position sensor, and at the same time an electrostatic force actuator. The force under measurement is balanced by a compensation electrostatic force which is traceable to electrical and length standards. A commercial cantilever-type micro-force probe was used in this calibration experiment. The force probe was brought to contact with and press into the load button (a ruby sphere) of the force measurement system by a closed-loop controlled z-scanner. The spring constant was obtained from the average slope determined from measured force-displacement curves and was found to be (2.26 ± 0.01) N/m where the given uncertainty is one standard deviation. We have successfully demonstrated the calibration of the microforce probe using our self-developed electrostatic sensing and actuating force measurement system. The measured spring constant is consistent with the manufacturer's specification, and the relative standard deviation is less than 0.5%.

Note from Publisher: This article contains the abstract only.

A novel use of the LiDAR sensor of a smartphone spring in introductory physics experiments is discussed in this paper. We have determined the spring constant for various combinations of springs using the LiDAR sensor of a smartphone through the phyphox application. An electrical heater coil is used as a spring, and the period of oscillation of a vertical spring–mass system is measured using a LiDAR sensor. The experimental values of spring constants agree with the theoretical values. A high school student can perform this simple experiment in a smart way at home.

In this study, in order to make a wide range displacement amount of nanopositioning stage and precision positioning, so design a flexible nanopositioning stage structure to meet this requirement. In this study, three different shape of the spring with four different shapes of the rib to analyze various combinations of, seen from the analysis results, when spring appearance as a cross-type (S1 type), the displacement of the shape of a wave-shaped rib (R1 type) portfolio the minimum amount of errors, and successfully analyze its spring constant and the resonant modal. The results were available for follow-up production when the reference platform.