Ultramacrocyclization in water via external templation

Condensing a bisaldehyde and a bisacylhydrazide in water in the presence of cucurbit[8]uril, produced an ultra-large ring whose framework contains more than one hundred atoms.

Study on dynamic mechanical properties of O-ring with large ring diameter ratio based on metal rubber

The demand for High temperature resistant metal rubber seals (MRS) with large ring-to-diameter ratio is very urgent in the industrial field. In this work, an O-type MRS with a large ring-to-diameter ratio was developed by embedding the spiral network metal rubber into the stainless steel ring with a special preparation process. The effects of frequency, porosity, and amplitude on the dynamic experimental performance of O-type MRS were studied in detail. The mechanical properties of the MRS were characterized by dynamic tests, and the damping sensitivity were analyzed by orthogonal tests. The results show that MRS has better stability under different frequencies of vibration. The energy consumption and loss factor of the sample increase with increases of porosity. With an increase in loading amplitude, the energy consumption and loss factor of the same porosity test sample increases, whereas the dynamic average stiffness of the specimen gradually decreases. Furthermore, the range analysis of the orthogonal experiment shows that the factors affecting the damping performance of the seal are porosity>amplitude>frequency. This study fills in the dynamic mechanical properties of O-shaped MRS, and provides a certain foundation for the engineering application of O-shaped MRS.

The Study of the Metal’s Flow Distribution during Rolling in Cutout Strikers for Different Schemes of the Stress State

In the forging industry, rolling is used to produce ring forgings, which are widely used in power and nuclear engineering. According to the technical conditions and established practice, large ring forgings are made using the operations of precipitation, piercing and rolling out with a striker on the mandrel.

A Comparison of Beat Frequency Estimation Methods for Large Ring Laser

Autoregressive (AR2) technique has always been used to estimate frequency of the output signal from Large ring laser. However, the acquisition rate is not at near real time which is the requirement and noise level still challenge the process resulting to errors in the final estimation. A research was done to compare the Autoregressive (AR2) with the counterparts such as Pisarenko, Quinn, Hilbert and Phase looking for a better technique that will estimate the frequency at near real time to minimize errors. Secondary data from G and C – II ring laser were used during the comparison between the techniques and Autoregressive (AR2). Results shows that, the output characteristics from the counterpart does not depict the oscillations of the Earth rotation as expected contrast to that of Autoregressive (AR2) which does. Moreover, there were much deviation from the expected true value for the techniques contrast to that of AR2 which is very minimum. On the other hand, when the C – II data were used, it was observed that both techniques resemble on their output characteristics though AR2 was still better in the acquisition rate expect for Hilbert transform which does not resemble with others. Following the scope of this paper, Autoregressive (AR2) technique still emerge as a favorite frequency estimation technique contrast to the four counterparts due to its robustness, high acquisition rate as well as low noise level.