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Mechanical tests were carried out at room temperature to reveal the effect of hydrogen content (0.2–1.2 wt.%) on the compressive properties of TC21 alloy. Results show that different hydrogen contents have distinct effects on microstructures and compressive properties of TC21 alloy. With the increase of hydrogen content, the amounts of α phase and acicular α′ martensite phase decrease, while the amounts of β phase and δ hydride increase, δ hydrides distribute along phase/grain boundaries first and then precipitate in β phase. As hydrogen content increases, the yield strength and microhardness decrease first and then increase, and the ultimate compressive strength decreases. The ultimate compression changes little first, and then increases up to a maximum, and finally decreases with the increase of hydrogen content. The optimum hydrogen content is about 0.9 wt.%, with which TC21 alloy exhibits higher plasticity and lower flow stress. Moreover, the fracture mode of TC21 alloys with hydrogen content less than 1.0 wt.% is a ductile fracture, while the fracture mode of the alloy with 1.2 wt.% hydrogen is a transgranular brittle fracture caused by hydride. Reasons for the distinct effect of hydrogen content on the room-temperature compressive properties are discussed. Keywords: TC21 alloy, Hydrogen content, Compressive properties, Microstructure, Fractography

High temperature superconducting (HTS) power cable shows high application prospect in modern power transmission, as it is superior over conventional transmission lines in high engineering current density and environmental friendliness. Its configuration is generally composed of several HTS layers designed with the principle of uniform current distribution, but there are few experimental results to verify the distribution. In this paper, a HTS cable model was designed based on the principle of uniform current, and the current distributions among layers in an HTS cable model were measured by Rogowski coils. The results provide an important basis for design of multi-layer HTS cable.

The main goal of this paper is to develop a novel approach for vibration control on a piezoelectric rotating truss structure. This study will analyze the dynamics and control of a flexible structure system with multiple degrees of freedom, represented in this research as a clamped–free–free–free truss type plate rotated by motors. The controller has two separate feedback loops for tracking and damping, and the vibration suppression controller is independent of position tracking control. In addition to stabilizing the actual system, the proposed proportional–derivative (PD) control, based on genetic algorithm (GA) to seek the primary optimal control gain, must supplement a fuzzy control law to ensure a stable nonlinear system. This is done by using an intelligent fuzzy controller based on adaptive neuro-fuzzy inference system (ANFIS) with GA tuning to increase the efficiency of fuzzy control. The PD controller, in its assisting role, easily stabilized the linear system. The fuzzy controller rule base was then constructed based on PD performance-related knowledge. Experimental validation for such a structure demonstrates the effectiveness of the proposed controller. The broad range of problems discussed in this research will be found useful in civil, mechanical, and aerospace engineering, for flexible structures with multiple degree-of-freedom motion.

Background: DNA methylation has been implicated in the pathogenesis of allergy and atopy. This study aimed to identify whether DNA methylation also plays an important role in the pathogenesis of nasal polyps (NP). Methodology: NP tissues were obtained from 32 patients with chronic rhinosinusitis with bilateral NP. Biopsies of inferior turbinate mucosa (ITM) were taken from 18 patients who underwent rhinoseptoplasty (control group). The methylated genes, which were detected by DNA methylation microarray, were validated by methylation-specific polymerase chain reaction, bisulphite sequencing, real-time polymerase chain reaction and immunohistochemistry. Results: DNA methylation microarray identified 8,008 CpG islands in 2,848 genes. One hundred and ninety-eight genes were found to have a methylated signal in the promoter region in NP samples compared with ITM samples. The four top genes that changed, COL18A1, EP300, GNAS and SMURF1, were selected for further study. The methylation frequency of COL18A1 was significantly higher in NP samples than in ITM samples. Conclusions: DNA methylation might play an important role in the pathogenesis of NP. Promoter methylation of COL18A1 was found to be significantly increased in NP tissues, further studies are necessary to confirm the significance of these epigenetic factors in the mechanisms underlying the development or persistence of NP.

This study will analyze the dynamics and control of a flexible structure system with multiple degrees of freedom, represented in this research as a clamped-free-free-free truss type plate rotated by motors. The controller has two separate feedback loops for tracking and damping, and the vibration suppression controller is independent of position tracking control. In addition to stabilizing the actual system, the proposed proportional-derivative (PD) control, based on genetic algorithm (GA) to seek the primary optimal control gain, must supplement a fuzzy control law to ensure a stable nonlinear system. This is done by using an intelligent fuzzy controller based on adaptive neuro-fuzzy inference system (ANFIS) with GA tuning to increase the efficiency of fuzzy control. The PD controller, in its assisting role, easily stabilized the linear system. The fuzzy controller rule base was then constructed based on PD performance-related knowledge.

Novel poly(aryl ether ketone)s were synthesized by nucleophilic substitution reactions of difluoromonomer with 4,4'-biphenol and substituted hydroquinone. The results showed that the novel polymers exhibited multiple phase transitions and formed optical birefringence textures above their melting transitions.