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Nowadays, the focus of flow shops is the adoption of customized demand in the context of service-oriented manufacturing. Since production tasks are often characterized by multi-variety, low volume, and a short lead time, it becomes an indispensable factor to include supporting logistics in practical scheduling decisions to reflect the frequent transport of jobs between resources. Motivated by the above background, a hybrid method based on dual back propagation (BP) neural networks is proposed to meet the real-time scheduling requirements with the aim of integrating production and transport activities. First, according to different resource attributes, the hierarchical structure of a flow shop is divided into three layers, respectively: the operation task layer, the job logistics layer, and the production resource layer. Based on the process logic relationships between intra-layer and inter-layer elements, an operation task–logistics–resource supernetwork model is established. Secondly, a dual BP neural network scheduling algorithm is designed for determining an operations sequence involving the transport time. The neural network 1 is used for the initial classification of operation tasks’ priority; and the neural network 2 is used for the sorting of conflicting tasks in the same priority, which can effectively reduce the amount of computational time and dramatically accelerate the solution speed. Finally, the effectiveness of the proposed method is verified by comparing the completion time and computational time for different examples. The numerical simulation results show that with the increase in problem scale, the solution ability of the traditional method gradually deteriorates, while the dual BP neural network has a stable performance and fast computational time.

To effectively improve the precision compensation and rigidity, according to the structural characteristics of vertical composite machining machine tools, the hysteresis moment precision compensation method was proposed. By optimizing the constrained position, the precision of non-structural geometric changes was effectively compensated. The hysteresis moment precision compensation method proposed in this paper can be well adapted to the micron precision compensation design of machine tools.

To solve the problem of unstable precision caused by local micrometre and submicron level flexible displacement generated by the self-weight of key components in precision mechanical motion systems, a flexible moment precision compensation method is proposed for precision turning milling composite machining machines. Firstly, the mechanism of flexible moment precision compensation technology for spindle components, linear motion pair components, column support posture, bed body and flat table contact was analysed. Secondly, the optimization design method for flexible moment precision compensation was proposed. Finally, the optimization design of flexible moment precision compensation was carried out for spindle components, bed body and base. The flexible moment compensation method proposed in the article has important reference value for improving the precision and stability of machine tools.

Controlling intake noise has always been a challenge in the commercial vehicle industry. In the field of heavy-duty commercial vehicles, due to the strong excitation energy and broad noise frequency band of air compressors, accurately diagnosing noise characteristics and effectively controlling these issues have become common challenges in the industry. This paper addresses the noise issue of a specific model of heavy-duty commercial vehicle's air compressor. Based on the key frequencies and distribution characteristics, a targeted control scheme was developed. After on-site validation, the control scheme demonstrated ideal performance, effectively mitigating the air compressor noise issue, providing a valuable reference for controlling air compressor noise in heavy-duty commercial vehicles.

Background An increasing prevalence of mental disorders (MDs) has been reported among children and adolescents. However, only few studies have conducted ocular examinations, including those on refractive status, in these groups of patients. Thus, the purpose of this study was to evaluate the refractive status and ocular findings in children and adolescents with MDs compared with matched controls with similar socioeconomic backgrounds. Methods A total of 178 participants with MDs and 200 controls were recruited between April 2021 and May 2022. All the children and adolescents underwent cycloplegic or noncycloplegic autorefraction and retinoscopy, slit-lamp biomicroscopy, and dilated fundus examinations. Ocular alignment was assessed using Hirschberg, Krimsky, or prism cover tests. The prevalence of refractive errors and ocular findings was the main outcome. Results Twenty-seven percent of patients with MDs and 8% of controls had ocular findings, the most common of which were conjunctivitis, keratitis, and trichiasis. For refractive status, 70% (124/178) of patients with MDs had myopia ≤-1.00 DS, and 2% (4/178) had hyperopia ≥+2.00 DS. In the control group, 70% (140/200) of patients had myopia ≤-1.00 DS, and 1% (2/200) had hyperopia ≥+2.00 DS. No differences were observed between the MD and control groups. However, the patients in the MD group (14.25±2.69 years) were significantly more susceptible to strabismus ( P <0.05) and amblyopia ( P <0.01) than those in the control group (13.65±3.04 years). There was a substantial difference between the two groups in the time spent on screen-based devices ( P <0.001). Furthermore, mental retardation (OR=3.286, P <0.01), emotional disorders (OR=2.003, P <0.01), and adjustment disorders (OR=2.629, P <0.01) were associated with an increased risk of amblyopia. Depression (OR =1.362, P <0.01) and emotional disorders (OR=2.205, P <0.01) were associated with a higher prevalence of strabismus. Conclusion Ophthalmological examinations should be performed in children and adolescents with MDs because MDs are associated with a high prevalence of refractive errors and ocular diseases. Detection and intervention of ocular and refractive findings in children and adolescents with MDs are necessary and effective in alleviating the economic burden in healthcare and improving individuals' quality of life

The oxide dispersion strengthened Mo alloys (ODS-Mo) prepared by traditional ball milling and subsequent sintering technique generally possess comparatively coarse Mo grains and large oxide particles at Mo grain boundaries (GBs), which obviously suppress the corresponding strengthening effect of oxide addition. In this work, the Y 2 O 3 and TiC particles were simultaneously doped into Mo alloys using ball-milling and subsequent low temperature sintering. Accompanied by TiC addition, the Mo−Y 2 O 3 grains are sharply refined from 3.12 to 1.36 µm. In particular, Y 2 O 3 and TiC can form smaller Y−Ti−O−C quaternary phase particles (∼230 nm) at Mo GBs compared to single Y 2 O 3 particles (∼120 nm), so as to these new formed Y−Ti−O−C particles can more effectively pin and hinder GBs movement. In addition to Y−Ti−O−C particles at GBs, Y 2 O 3 , TiO x , and TiC x nanoparticles (<100 nm) also exist within Mo grains, which is significantly different from traditional ODS-Mo. The appearance of TiO x phase indicates that some active Ti within TiC can adsorb oxygen impurities of Mo matrix to form a new strengthening phase, thus strengthening and purifying Mo matrix. Furthermore, the pure Mo, Mo−Y 2 O 3 , and Mo−Y 2 O 3 −TiC alloys have similar relative densities (97.4%–98.0%). More importantly, the Mo−Y 2 O 3 −TiC alloys exhibit higher hardness (HV 0.2 (425 ± 25)) compared to Mo−Y 2 O 3 alloys (HV 0.2 (370 ± 25)). This work could provide a relevant strategy for the preparation of ultrafine Mo alloys by facile ball-milling.

The oxide dispersion strengthened Mo alloys(ODS-Mo)prepared by traditional ball milling and subsequent sintering technique generally possess comparatively coarse Mo grains and large oxide particles at Mo grain boundaries(GBs),which obviously suppress the cor-responding strengthening effect of oxide addition.In this work,the Y2O3 and TiC particles were simultaneously doped into Mo alloys using ball-milling and subsequent low temperature sintering.Accompanied by TiC addition,the Mo-Y2O3 grains are sharply refined from 3.12 to 1.36 pm.In particular,Y2O3 and TiC can form smaller Y-Ti-O-C quaternary phase particles(～230 nm)at Mo GBs compared to single Y2O3 particles(～420 nm),so as to these new formed Y-Ti-O-C particles can more effectively pin and hinder GBs movement.In addition to Y-Ti-O-C particles at GBs,Y2O3,TiOx,and TiCx nanoparticles(＜100 nm)also exist within Mo grains,which is significantly different from traditional ODS-Mo.The appearance of TiOx phase indicates that some active Ti within TiC can adsorb oxygen impurities of Mo matrix to form a new strengthening phase,thus strengthening and purifying Mo matrix.Furthermore,the pure Mo,Mo-Y2O3,and Mo-Y2O3-TiC alloys have similar relative densities(97.4％-98.0％).More importantly,the Mo-Y2O3-TiC alloys exhibit higher hardness(HV0.2(425±25))com-pared to Mo-Y2O3 alloys(HV0.2(370±25)).This work could provide a relevant strategy for the preparation of ultrafine Mo alloys by facile ball-milling.

We report here investigations on the superstructure modulation induced by the ordering of carbon vacancies in the nonstoichiometric zirconium carbide of ZrC0.61, which was prepared by spark plasma sintering (SPS) of the mechanochemically synthesized ZrCx nanopowders. The sintered ZrC0.61 is found to exhibit an interesting microstructure of interlaced laminated sheets. In contrast to the previous long duration post annealing for realization of the ordered carbon vacancies in the rocksalt-structured transition metal carbide, the ordered carbon vacancies are directly obtained during the SPS process, and no post-annealing period is necessary. With the help of transmission electron microscopy, the superstructural nanodomains with the average size of ∼30 nm are identified.

We report here investigations on the superstructure modulation induced by the ordering of carbon vacancies in the nonstoichiometric zirconium carbide of ZrC 0.61 , which was prepared by spark plasma sintering (SPS) of the mechanochemically synthesized ZrC x nanopowders. The sintered ZrC 0.61 is found to exhibit an interesting microstructure of interlaced laminated sheets. In contrast to the previous long duration post annealing for realization of the ordered carbon vacancies in the rocksalt-structured transition metal carbide, the ordered carbon vacancies are directly obtained during the SPS process, and no post-annealing period is necessary. With the help of transmission electron microscopy, the superstructural nanodomains with the average size of ∼30 nm are identified.