A Symmetric-Actuating Linear Piezoceramic Ultrasonic Motor Capable of Producing a Scissoring Effect.

Conventionally, to produce a linear motion, one motor's stator is employed to drive one runner moving forward or backward. So far, there is almost no report of one electromechanical motor or piezoelectric ultrasonic motor that can directly generate two symmetrical linear motions, while this function is desired for precise scissoring and grasping in the minimally invasive surgery field. Herein, we report a brand-new symmetric-actuating linear piezoceramic ultrasonic motor capable of generating symmetrical linear motions of two outputs directly without additional mechanical transmission mechanisms.

Emission trading scheme, technological innovation, and competitiveness: Evidence from China's thermal power enterprises.

As flagship climate policy instruments, emission trading schemes (ETSs) are spreading, accelerating and strengthening globally. This study aims to explore whether the Porter hypothesis is present in China's ETS. Using the most recent data from 351 thermal power enterprises, the proposed agent-based model (ABM) creates a virtual decision-making and trading mechanism to identify ETS policy effects on enterprise technological innovation and competitiveness.

A 4D x-ray computer microtomography for high-temperature electrochemistry.

High-temperature electrochemistry is widely used in many fields. However, real-time observations and an in-depth understanding of the inside evolution of this system from an experimental perspective remain limited because of harsh reaction conditions and multiphysics fields. Here, we tackled this challenge with a high-temperature electrolysis facility developed in-house.

An in situ microtomography apparatus with a laboratory x-ray source for elevated temperatures of up to 1000 °C.

An elevated-temperature in situ microtomography apparatus that can measure internal damage parameters under tensile loads at high temperatures up to 1000 °C is developed using a laboratory x-ray source. The maximum resolution of the apparatus can reach 3 µm by a reasonable design. A high-temperature environment is accomplished by means of a heating chamber based on a radiation technique using four halogen lamps with ellipsoidal reflectors.

Polybenzoxazines: Thermal Responsiveness of Hydrogen Bonds and Application as Latent Curing Agents for Thermosetting Resins.

This work aims at exploring the application of polybenzoxazines as thermal latent curing agents for epoxy resins. Thorough studies have shown that hydrogen bonds of polybenzoxazines block the reactivity of phenolic hydroxyl at ambient temperatures and break at elevated temperatures to release the free phenolic hydroxyl. On the basis of these findings, polybenzoxazines are used as thermal latent curing agents.

Influence of substituent on equilibrium of benzoxazine synthesis from Mannich base and formaldehyde.

N-Substituted aminomethylphenol (Mannich base) and 3,4-dihydro-2H-3-substituted 1,3-benzoxazine (benzoxazine) were synthesized from substituted phenol (p-cresol, phenol, p-chlorophenol), substituted aniline (p-toluidine, aniline, p-chloroaniline) and formaldehyde to study influence of substituent on equilibrium of benzoxazine synthesis from Mannich base and formaldehyde. (1)H-NMR and charges of nitrogen and oxygen atoms illustrate effect of substituent on reactivity of Mannich base, while oxazine ring stability is characterized by differential scanning calorimetry (DSC) and C-O bond order. Equilibrium constants were tested from 50 °C to 80 °C, and the results show that substituent attached to phenol or aniline has same impact on reactivity of Mannich base; however, it has opposite influence on oxazine ring stability and equilibrium constant.

Reaction-induced phase separation in a bisphenol A-aniline benzoxazine-N,N'-(2,2,4-trimethylhexane-1,6-diyl)bis(maleimide)-imidazole blend: the effect of changing the concentration on morphology.

The effect of the concentration changes on morphology was researched by modulating the molar ratio of bisphenol A-aniline benzoxazine (BA-a) and N,N'-(2,2,4-trimethylhexane-1,6-diyl)bis(maleimide) (TBMI); the relationships between the concentration changes, the curing rate, rheological properties, and morphologies of blends were examined in this paper. The cured blends showed different morphologies at different concentrations, and the morphologies changed from a sea-island structure to a bi-continuous structure followed by a homogeneous structure when the molar ratio of BA-a was decreased. This effect was caused by the relative rates of the phase separation and the curing reaction.