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In this paper, (0.2–1 wt%) Yb was added to improve the tensile properties and high-cycle fatigue behavior of the as-cast and as-extruded Mg-10Li-5Zn-0.5Er alloys. It is found that Yb mainly affects the mechanical properties of the alloy by changing the grain size, type and morphology of the second phases. Yb mainly exists in the formation of Mg2Yb and Mg-Zn-Yb phases in the metallographic structure. With the addition of Yb, the grains are refined and these Yb-containing phases replace the large-sized MgLiZn phase to be enriched at the grain boundaries. While the addition of excess Yb reduces the number of small-sized MgLiZn phases in the grain, thus reducing the alloys’ mechanical performance. After extrusion, the small-sized MgLiZn phase is refined and the number increases, which effectively improves the tensile and fatigue strength of the alloy. The fatigue strength is mainly affected by the number and morphology of the second phase, positively correlated with the strength. Balanced in grain size and number and size of second phases, the extruded alloy with 0.2Yb added exhibits excellent mechanical properties with the yield strength, ultimate tensile strength and elongation of 292 MPa, 303 MPa and 11.7%, and an fatigue strength of 130 MPa.

Abstract Background Post-radiation nasopharyngeal necrosis (PRNN) is a severe adverse event following re-radiotherapy for patients with locally recurrent nasopharyngeal carcinoma (LRNPC) and associated with decreased survival. Biological heterogeneity in recurrent tumors contributes to the different risks of PRNN. Radiomics can be used to mine high-throughput non-invasive image features to predict clinical outcomes and capture underlying biological functions. We aimed to develop a radiogenomic signature for the pre-treatment prediction of PRNN to guide re-radiotherapy in patients with LRNPC. Methods This multicenter study included 761 re-irradiated patients with LRNPC at four centers in NPC endemic area and divided them into training, internal validation, and external validation cohorts. We built a machine learning (random forest) radiomic signature based on the pre-treatment multiparametric magnetic resonance images for predicting PRNN following re-radiotherapy. We comprehensively assessed the performance of the radiomic signature. Transcriptomic sequencing and gene set enrichment analyses were conducted to identify the associated biological processes. Results The radiomic signature showed discrimination of 1-year PRNN in the training, internal validation, and external validation cohorts (area under the curve (AUC) 0.713–0.756). Stratified by a cutoff score of 0.735, patients with high-risk signature had higher incidences of PRNN than patients with low-risk signature (1-year PRNN rates 42.2–62.5% vs. 16.3–18.8%, P

The present work reports the creep behavior and microstructural evolution of the sand-cast Mg–14Gd–0.4Zr alloy (wt.%) prepared by the differential pressure casting machine. Their compressive creep tests at 250 °C were performed under various applied stresses (i.e., 60, 80 and 100 MPa). Among them, the sand-cast Mg–14Gd–0.4Zr samples examined under 250 °C/80 MPa for 39 and 95 h, respectively, were chosen to systemically analyze their creep mechanisms using high-angle annular dark field-scanning transmission electron microscopy (HAADF-STEM). The obtained results showed that the enhancement of creep resistance can be mainly attributed to the coherent β' and β'F phases with an alternate distribution, effectively impeding the basal dislocations movement. However, with the creep time increasing, the fine β'+β'F precipitate chains coarsened and transformed to semi-coherent β1 phase and even to large incoherent β phase (surrounded by precipitate-free areas) in grain interiors. The precipitate-free zones (PFZs) at grain boundaries (GBs) were formed, and they could expand during creep deformation. Apart from the main cross-slip of basal and prismatic dislocations, type dislocations were activated and tended to distribute near the GBs. The aforementioned phenomena induced the stress concentrations, consequently leading to the increment of the creep strain.

In order to improve the ductility of commercial WE43 alloy and reduce its cost, a Mg-3Y-2Gd-1Nd-0.4Zr alloy with a low amount of rare earths was developed and prepared by sand casting with a differential pressure casting system. Its microstructure, mechanical properties and fracture behaviors in the as-cast, solution-treated and as-aged states were evaluated. It is found that the aged alloy exhibited excellent comprehensive mechanical properties owing to the fine dense plate-shaped β' precipitates formed on prismatic habits during aging at 200 °C for 192 hrs after solution-treated at 500 °C for 24 hrs. Its ultimate tensile strength, yield strength, and elongation at ambient temperature reach to 319 ± 10 MPa, 202 ± 2 MPa and 8.7 ± 0.3% as well as 230 ± 4 MPa, 155 ± 1 MPa and 16.0 ± 0.5% at 250 °C. The fracture mode of as-aged alloy was transferred from cleavage at room temperature to quasi-cleavage and ductile fracture at the test temperature 300 °C. The properties of large-scale components fabricated using the developed Mg-3Y-2Gd-1Nd-0.4Zr alloy are better than those of commercial WE43 alloy, suggesting that the new developed alloy is a good candidate to fabricate the large complex thin-walled components.

Nano-opto-electro-mechanical systems (NOEMS), considered as new platforms to study electronic and mechanical freedoms in the field of nanophotonics, have gained rapid progress in recent years. NOEMS offer exciting opportunities to manipulate information carriers using optical, electrical, and mechanical degrees of freedom, where the flow of light, dynamics of electrons, and mechanical vibration modes can be explored in both classical and quantum domains. By exploiting NOEMS concepts and technologies, high speed and low-power consumption switches, high-efficiency microwave-optical conversion devices, and multiple quantum information processing functions can be implemented through on-chip integration. This review will introduce the principles of NOEMS, summarize the recent developments, and important achievements, and give a prospect for the further applications and developments in this field.

Graphite nanoparticles (GNPs) were introduced into poly(p-phenylene benzobisoxazole) (PBO) matrix to produce composites via in situ polymerisation. Films of various composites were fabricated through the solution casting method in methanesulfonic acid (MSA) with the help of two sand core plates. The interlayer spacing of GNPs increased slightly confirmed by XRD as a result of an expanding effect caused by continuously formed PBO chains between the graphene nanosheets of GNPs during polymerisation. Also, due to the uniform dispersion of GNPs into PBO matrix, composite films exhibited an improved tensile strength (258 MPa, 72% higher than that of pure PBO) with 5 wt% loading of GNPs fillers. The initial decomposition temperature of the composite is ∼630°C. Besides, benefitting from the interfacial polarisation in this conductive filler/polymer system, the dielectric constant of the composites with 10 wt% loading of GNPs reached 6.96, which were over two times higher than that of pristine PBO polymer (2.91).

In view of the problem of high energy consumption of existing high-power electrical haulage shearers, the paper proposed a design scheme of energy-saved frequency conversion speed regulation system based on TMS320LF2407A with dual inverters-dual motors and introduced components of the system. It analyzed working principle and gave energy-saved computational formula of the system as well. The system takes AC asynchronous motor as simulation load, dual inverters were connected in parallel at DC bus side, uses DSP to real-timely control and track servo system, and realizes change of motor state of electrical haulage shearer. The system provided dilivery loop of energy feedback too. The simulation result of Matlab proved that principle of the system is correct and energy-saved effect is remarkable.

Sensors play an important role in the execution of robot tasks as an important component of understanding the world. In this paper, we propose a role-based sensor management framework on ROS (Robot Operating System), in which the role is a set of information needed for robot sensor development. Firstly, we develop a sensor management interface to facilitate the development of sensor applications on robot. And a subscriber module is proposed to shield the details of the sensor driver and the communication between processes, the sensor drivers on the robot are effectively managed. Robot sensors have different executive ability in different situations when robot performing tasks. For example, we know that RGB camera can collect a clear image when the light is strong, while generate a blurred image in weak light environment. Secondly, we propose an environment based sensor role dynamic evaluation mechanism to get the confidence of sensor in a certain environment. The confidence represents the executive ability of sensor when performing tasks. The confidence provides the basis for switching the task schemes. In the mechanism we can dynamically configure the environment information and confidence calculation method. In the experiment phase, we verify the effectiveness of the framework through a robot patrol task. Experiment results show that our framework can effectively manage the robot sensors with a certain environmental adaptability.

As taxis play an increasingly important role in urban traffic system, the research on the supply and demand of taxis and the design of an optimal model of taxis supply has an importantly practical significance. In this paper, we used the traffic bureau data of Guangzhou, and determined the rate of empty driving as the index to establish the model. Nonlinear programming method was uesd to establish the optimal model of taxis quantity to meet the maximum income and maximum passenger satisfaction. Finally we got the optimal number of taxis was 37537.59