摘要：Superplasticizers are widely used to reduce the pipe flow resistance of cemented paste backfill(CPB), which is characterised by high concentration and high yield stress. This study aimed to assess the time-dependent rheological properties of CPB containing superplasticizer, with special focus on static yield stress and thixotropy. The results indicate that with the increase of the superplasticizer dosage, the static yield stress, dynamic yield stress and thixotropy of CPB decreased significantly, while the plastic viscosity decreased slightly. The curing time has a significant effect on the static yield stress, dynamic yield stress and thixotropy of CPB containing superplasticizer, which increase by 46.6%-87.1%,15.2%-35.6% and 79.4%-138.2%, respectively, within 2 h. The static yield stress, dynamic yield stress and thixotropy of CPB without superplasticizer only increase by 4.9%, 6.3% and 16.1%, respectively, within 2 h. The curing time has a significant influence on the plastic viscosity of CPB regardless of superplasticizer addition, the plastic viscosity increases by 13.2%-19.7% within 2 h. Regardless of superplasticizer dosage, plotting of both static yield stress and dynamic yield stress versus thixotropy produces clearly linear curves. The findings of this study are conducive to the design of pipe transportation of CPB containing superplasticizer.

摘要：To ensure compacted backfilling, it is essential to ensure the reliability of the performance of a solid backfill support, key equipment for integrating backfilling and mining. To evaluate the backfilling performance of a backfill support, the concept of backfill and operation properties is proposed in this study. Moreover, it is elaborated in terms of five aspects, namely, structural property, supporting property, tamping property, mechanical response property, and geological adaptation property, which are specifically reflected by 14 indexes including the supporting intensity and vertical roof gap. Seven separate evaluation indexes are selected to build a backfill and operation properties based system for evaluating the design schemes of the backfill support via a multi-index comprehensive evaluation method; then, the evaluation method and process together with measures to control the backfill and operation properties are proposed. By using this system, 11 schemes for optimizing the ZC5200/14.5/3 backfill support at Zhaizhen Coal Mine are evaluated, and scheme #10 is found to show superior vertical roof gap and other backfill and operation properties, thus demonstrating the reasonability of the evaluation system. On this basis, the backfill support research framework of designing initial scheme, optimizing design scheme, selecting the best evaluation indexes, evaluating optimizing scheme, and evaluating operation properties is built; this should serve as an important reference for further studies on the roof controlling performance of a backfill support.

摘要：Wear and scuffing failures often occur in marine transmission gears due to high friction and flash temperature at the interface between the *** this paper,a numerical solution procedure was developed for the predictions of transient friction and flash temperature in the marine timing gears during one meshing circle based on the 3D line contact mixed lubrication simulation,which had been verified by comparing the flash temperature with those from Blok’s *** effect of machined surface roughness on the mixed lubrication characteristics is *** obtained results for several typical gear pairs indicate that gear pair 4-6 exhibits the largest friction and the highest interfacial temperature increase due to severe rough surface asperity contacts,while the polished gear surfaces yield the smallest friction and the lowest interfacial *** addition,the influences of the operating conditions and the gear design parameters on the friction-temperature behaviors are *** is observed that the conditions of heavy load and low rotational velocity usually lead to significantly increased friction and *** the meantime,by optimizing the gear design parameters,such as the modulus and the pressure angle,the performance of interfacial friction and temperature can be significantly improved.

摘要：In recent years, with the increase of the depth of open-pit mining, the pollution level has been on the rise due to harmful gases and dust occurring in the process of mining. In order to accelerate the diffusion of these air pollutants, the distributed regularity of the rock face temperature which is directly related to the air ventilation in deep open-pit mines should be studied. Here, we establish the key factors influencing the rock face temperature in a deep open-pit mine. We also present an empirical model of the rock face temperature variation in the deep open-pit mine, of which the performance is interestingly high compared with that of the field test. This study lays a foundation to study the ventilation thermodynamic theory in the deep open-pit mine, which is of great importance for theoretical studies and engineering applications of solving air pollution problem in deep open-pit mines.

摘要：Direct adaptive fuzzy sliding mode control design for discrete non-affine nonlinear systems is presented for trajectory tracking problems with disturbance. To obtain adaptiveness and eliminate chattering of sliding mode control, a dynamic fuzzy logical system is used to implement an equivalent control, in which the parameters are self-tuned online. Stability of the sliding mode control is validated using the Lyapunov analysis theory. The overall system is adaptive, asymptotically stable, and chattering-free. A numerical simulation and an application to a robotic arm with two degrees of freedom further verify the good performance of the control design.

摘要：The Box–Behnken design and desirability approach were used to investigate and optimize the process parameters for aluminum reduction cells related to alumina dissolution. The bath temperature, alumina content, current and alumina temperature were chosen as the design parameters. The content of cumulative dissolved alumina(CCDA) and the relative deviation from the target content(RDTC) were adopted as the responses. The interactive influence results show that increasing the bath temperature and alumina temperature, as well as decreasing the alumina content, can increase CCDA. Increasing the bath temperature and lowering the current are beneficial for obtaining a more uniform alumina distribution. The optimal operating parameters were determined to be as follows: bath temperature of 958.8 ℃, alumina content of 2.679 wt.%, current of 300 kA and alumina temperature of 200 ℃.

摘要：Taking advantage of the new standard HTML5,we designed an online tool called a browser/server-based glaucoma image database builder(BGIDB)for the demarcation of the optic disk and cup’s ellipse-like *** B-spline interpolation algorithm is used,and a specially designed algorithm is proposed for classifying the disease grade according to the disc damage likelihood scale criterion,which is correlated strongly with the glaucoma process by *** tool exhibits the best performance with a low overlapping error of 4.34%for the optic disk demarcation and 8.31%for the optic cup *** also has preferable time-consuming as compared to other tools and is a cross-platform *** tool has already been utilized in building the ophthalmic image database in the cooperation of Center for Ophthalmic Imaging research and The Second Xiangya Hospital.

摘要：As the spring equation is limited to the accuracy of mill stiffness and the linearity of the mill spring curve, the traditional gaugemeter automatic gauge control(GM-AGC) system based on spring equation cannot meet the requirements of practical production. In allusion to this problem, a kind of novel GM-AGC system based on mill stretch characteristic curve was proposed. The error existing in calculating strip thickness by spring equation were analyzed first. And then the mill stretch characteristic curve which could effectively eliminate the influence of mill stiffness was described. The novel GM-AGC system has been applied successfully in a hot strip mill, the application results show that the thickness control precision is improved significantly, with the novel GM-AGC system, over 98.6% of the strip thickness deviation of 3.0 mm class can be controlled within the target tolerances of ±20 μm.

摘要：An EMU train with detailed cabin structural is established based on the finite element *** secondary impact between train driver and control desk is fully analysed and two measures are proposed to reduce the driver injury severity,such as the multi-objective optimization of the driver seat position and equipping the train with three-point seat *** results indicate that the driver seat position has a significant effect on the driver injury severity during a secondary *** to the multi-objective optimization,some Pareto solutions are suggested to design the driver seat *** that,it is also indicated although the chest and leg are well protected when the driver wears a two-point seat belt,it increases the head injure during a secondary *** the other hand,the three-point seat belt can supply the train driver with an overall protection against the secondary *** injury criteria(HIC,VC,TI)of the driver with the three-point seat belt is significantly lower than those of the driver without seat ***,according to the simulation analysis,the limited load of the three-point seat belt is suggested about 1.5 kN.

摘要：As the application of energy-absorption structure reaches an unprecedented scale in both academia and industry, a reflection upon the state-of-the-art developments in the crashworthiness design and structural optimization, becomes vital for successfully shaping the future energy-absorption structure. Physical impacting test and numerical simulation are the main methods to study the crashworthiness of railway vehicles at present. The end collision deformation area of the train can generally be divided into two kinds of structural design forms: integral absorbing structure design form and specific energy absorbing structure design form, and different energy-absorption structures introduced in this article can be equipped on different railway vehicles, so as to meet the balance of crashworthiness and economy. In pursuit of improving the capacity of energy dissipation in energy-absorption structures, studies are increasingly investigating multistage energy absorption systems, searching breakthrough when the energy dissipation capacity of the energy-absorption structure reaches its limit. In order to minimize injuries, a self-protective posture for occupants is also studied. Despite the abundance of energy-absorption structure research methods to-date, the problems of analysis and prediction during impact are still scarce, which is constituting one of many key challenges for the future.