摘要：The concave die design of self-pierce riveting(SPR) is of critical importance for product quality. The optimization of concave die parameters based on orthogonal test is proposed to explore the relationship between self-pierce riveted joint quality and die parameters. There are nine independent die parameter factors in orthogonal test and each factor has 4 levels. In order to evaluate the interlock and neck thickness, we carry out numerical simulations by the software DEFORM-2D. Then, the primary and secondary factors that affect the joint quality have been found out by means of range analysis. Finally, an optimization scheme is brought forward to design concave die in SPR process, which indicates that the joint has higher quality than that of former orthogonal *** work can be extended by a detailed mechanical and fatigue analysis for the joint quality of SPR process.

摘要：This study combined fault identification with a deep learning algorithm and applied a convolutional neural network(CNN)design based on an improved balanced crossentropy(BCE)loss function to address the low accuracy in the intelligent identification of seismic faults and the slow training speed of convolutional neural networks caused by unbalanced training sample *** network structure and optimal hyperparameters were determined by extracting feature maps layer by layer and by analyzing the results of seismic feature *** BCE loss function was used to add the parameter which is the ratio of nonfaults to the total sample sets,thereby changing the loss function to find the reference of the minimum weight parameter and adjusting the ratio of fault to nonfault *** method overcame the unbalanced number of sample sets and improved the iteration *** a brief training,the accuracy could reach more than 95%,and gradient descent was *** proposed method was applied to fault identification in an oilfield *** trained model can predict faults clearly,and the prediction results are basically consistent with an actual case,verifying the effectiveness and adaptability of the method.

摘要：In deep underground mining, the surrounding rocks are very soft with high stress. Their deformation and destruction are serious, and frequent failures occur on the bolt support. The failure mechanism of bolt support is proposed to solve these problems. A calculation theory is established on the bond strength of the interface between the anchoring agent and surrounding rocks. An analysis is made on the influence law of different mechanical parameters of surrounding rocks on the interfacial bond strength. Based on the research, a new high-strength bolt-grouting technology is developed and applied on site. Besides, some helpful engineering suggestions and measures are proposed. The research shows that the serious deformation and failure, and the lower bond strength are the major factors causing frequent failures of bolt support. So, the bolt could not give full play to its supporting potential. It is also shown that as the integrity, strength, interface dilatancy and stress of surrounding rocks are improved, the bond strength will increase. So, the anchoring force on surrounding rocks can be effectively improved by employing an anchoring agent with high sand content, mechanical anchoring means, or grouting reinforcement. The new technology has advantages in a high strength, imposing pre-tightening force, and giving full play to the bolt supporting potential. Hence, it can improve the control effect on surrounding rocks. All these could be helpful references for the design of bolt support in deep underground mines.

摘要：Under given heat duty and heat transfer area conditions, the equipartition of the entransy dissipation (EoED) principle, the equipartition of the temperature difference (EoTD) principle, and the equipartition of the heat flux (EoHF) principle are applied to the optimization design of a heat exchanger with a variable heat transfer coefficient. The results show that the difference between the results obtained using the EoED and EoTD principles is very small, far smaller than that between the results obtained using the EoED and EoHF principles. The correct entransy dissipation minimization principle is chosen to optimize the parameters in the hot and cold fluids in a two-fluid heat exchanger, under given heat duty and heat transfer area conditions. The results indicate that the proper choice of the two alternative fluids has an important role in the successful application of the entransy dissipation minimization principle. The fluid that could improve the total heat transfer coefficient should be chosen, or the fluid that makes the temperature profiles of the hot and cold fluids parallel and decreases the temperature difference between the hot and cold fluids after optimization simultaneously, could be the proper one.

摘要：Although graphite anodes operated with representative de/intercalation patterns at low potentials are considered highly desirable for K-ion batteries,the severe capacity fading caused by consecutive reduction reactions on the aggressively reactive surface is inevitable given the scarcity of effective protecting ***,by introducing a flame-retardant localized high-concentration electrolyte with retentive solvation configuration and relatively weakened anion-coordination and non-solvating fluorinated ether,the rational solid electrolyte interphase characterized by well-balanced inorganic/organic components is tailored in *** effectively prevented solvents from excessively decomposing and simultaneously improved the resistance against K-ion ***,the graphite anode retained a prolonged cycling capability of up to 1400 cycles(245 mA h g,remaining above 12 mon)with an excellent capacity retention of as high as 92.4%.This is superior to those of conventional and high-concentration ***,the optimized electrolyte with moderate salt concentration is perfectly compatible with graphite,providing a potential application prospect for K-storage evolution.

摘要：This study gives an analytical solution for wave interaction with a partially reflecting vertical wall protected by a submerged porous bar based on linear potential theory. The whole study domain is divided into multiple sub-regions in relation to the structures. The velocity potential in each sub-region is written as a series solution by the separation of variables. A partially reflecting boundary condition is used to describe the partial reflection of a vertical wall. Unknown expansion coefficients in the series solutions are determined by matching velocity potentials among different sub-regions. The analytical solution is verified by an independently developed multi-domain boundary element method(BEM) solution and experimental data. The wave run-up and wave force on the partially reflecting vertical wall are estimated and examined, which can be effectively reduced by the submerged porous bar. The horizontal space between the vertical wall and the submerged porous bar is a key factor, which affects the sheltering function of the porous bar. The wave resonance between the porous bar and the vertical wall may disappear when the vertical wall has a low reflection coefficient. The present analytical solution may be used to determine the optimum parameters of structures at a preliminary engineering design stage.

摘要：The control design problem plays a fundamental role in the study of logical control networks(LCNs).This paper presents a detailed survey on new developments in control design techniques of ***,some preliminary results on the semi-tensor product method and LCNs are ***,we move on to some new developments for control design techniques of LCNs,including the reachable set approach,the pinning control technique,the control Lyapunov function approach,the event-triggered control technique,and the sampled-data control ***,an illustrative example is given to demonstrate the effectiveness of these techniques.

摘要：To research the anchoring effect of large deformation bolt,tensile and drawing models are ***,the evolution laws of drawing force,bolt axial force and interfacial shear stress are ***,the influence of structure element position on the anchoring effect of large deformation bolt is *** last,the energy-absorbing support mechanism is *** show that during the drawing process of normal bolt,drawing force,bolt axial force and interfacial shear stress all gradually increase as increasing the drawing displacement,but when the large deformation bolt enters the structural deformation stage,these three values will keep stable;when the structure element of large deformation bolt approaches the drawing end,the fluctuation range of drawing force decreases,the distributions of bolt axial force and interfacial shear stress of anchorage section are steady and the increasing rate of interfacial shear stress decreases,which are advantageous for keeping the stress stability of the anchorage *** the working process of large deformation bolt,the strain of bolt body is small,the working resistance is stable and the distributions of bolt axial force and interfacial shear stress are *** a rock burst event occurs,the bolt and bonding interface cannot easily break,which weakens the dynamic disaster degree.

摘要：在这篇论文，我们处理追踪发生在活动收音机通讯的线性回归隧道模型的顺利变化时间的参数的问题。在考虑下面的系统与含糊的统计特征与围住的协变性和噪音受到变化时间的系数不确定性。追踪的问题的目的是发现过滤器参数以便追踪的表演，定义为追踪的错误的最少的吝啬的平方，被优化。处理问题的关键是追踪的问题被转变成过滤的并且用一个设计公式。一条多项式途径基于答案因为追踪的愿望被开发。柔韧的过滤器设计在这建议纸可以比没有随机的系数不确定性，为系统设计的标准最佳的过滤器有稍微更高计算的复杂性。然而，追踪的表演被改进。

摘要：Dual-functional NiCo2S4 polyhedral architectures with outstanding electrochemical performance for supercapacitors and lithium-ion batteries(LIBs) have been rationally designed and successfully synthesized by a hydrothermal method. The as-synthesized NiCo2S4 electrode for supercapacitor exhibits an outstanding specific capacitance of 1298 Fg-1 at 1 A g-1 and an excellent rate capability of ~80.4% at20 A g-1. Besides, capacitance retention of 90.44% is realized after 8000 cycles. In addition, the NiCo2S4 as anode in LIBs delivers high initial charge/discharge capacities of 807.6 and 972.8 m Ah g-1 at 0.5 C as well as good rate capability. In view of these points, this work provides a feasible pathway for assembling electrodes and devices with excellent electrochemical properties in the next generation energy storage applications.