Simplified Method and Influence Factors of Vibration Characteristics of Isolated Curved Girder Bridge

The isolated curved girder bridge's vibration characteristics play a major part in the seismic responses of structures and anti-seismic properties.A clear analytic relationship between design parameters and the system's vibration characteristics could be established by its simplified dynamic analysis model,making it convenient for providing a reference to the optimization of design and safety analysis.A double-mass six-degree-of-freedom model for curved girder bridges with isolation bearings installed at the top of the bridge piers is built and a simplified analysis method for the vibration characteristics of the system is provided.Combined with the Matlab programming,the influences of radius of curvature,central angle,bridge deck width and damping ratio of the isolation layer and circular frequency of the isolation layer of isolated curved girder bridges on the pseudo-undamped natural circular frequency(called pseudo-frequency for short)and system damping ratio are systematically analyzed,and the sensitivity of vibration characteristics of isolated curved girder bridges is studied.The results show that the vibration characteristics of isolated curved girder bridges can be reflected well with this simplified model and calculation method.The pseudo-frequency of curved girder and system damping ratios increases with the increase of the isolation layer.The third-order vibration characteristic is more sensitive to the parameters of a curved girder,and the first-order vibration characteristic is sensitive to both central angle and radius of curvature to some extent while insensitive to the width of the bridge deck.Furthermore,the second-order vibration characteristic is not sensitive to the parameters of a curved girder.

Skills for Translating Onomatopoeia in English Poems

Skills for Translating Onomatopoeia in English Poems aims for a better comprehension of translating skills for onomatopoeia in English poems. By introducing the definition of onomatopoeia, it proposes several methods of translating onomatopoeia. It suggests, it's better to keep the part of speech of onomatopoeia when translate an English poem for fully expressing the meaning of the original author;or change the part of speech of onomatopoeia if it is necessary, which are definitely explained by methods and examples including turning nouns into verbs, turning verbs into nouns and turning adjectives into verbs. It also points out one can add onomatopoeia to a text without onomatopoeia for other purposes.

Novel Concentric Tube Robot Based on Double-Threaded Helical Gear Tube

Nasopharyngeal carcinoma is a malignant tumor originating from the nasal mucosa. It is a malignanttumor of the head and neck. Concentric tube robot (CTR), as it can form a complicated shape and access hardto-reach lesions, is often used in minimally invasive surgeries. However, some CTRs are bulky because of theirtransmission design. In this paper, a light CTR based on double-threaded helical gear tube is proposed. Sucha CTR is less cumbersome than the traditional CTR as its actuation unit is compact and miniaturized. Themapping relationship between the gear tube attitude and motor output angle is obtained by kinematic analysis.The precision, stability, and repeatability of the driving mechanism are tested. The experimental results showthat the positioning error in the translation test is less than 0.3 mm, the rolling angle error in the stability testis less than 0.6◦, and the error in the translation repeatability test is less than 0.005 mm. Finally, a tip-targetingtest is performed using the new CTR, which verifies the feasibility of the CTR for surgeries.