摘要：Treatment of peat soil foundation in Yunnan surrounding Dianchi and Erhai Lakes poses complex problems for engineering *** is insufficient to rely on ordinary cement to reinforce peat *** order to make the reinforcement reliable,this experiment mixed(ultrafine cement)UFC into ordinary cement to form a composite solidify *** study aimed to analyze the influence of UFC proportion on the strength of cement-soil in the peat soil *** compressive strength(UCS)and scanning electron microscope(SEM)tests were conducted on samples soaked for 28 and 90 days,*** test results show that without considering the effects of Humic Acid(HA)and Fulvic Acid(FA),incorporating UFC can significantly improve the UCS of *** rapid hydration of the fine particles generates a large number of cementitious products,improves the cohesion of the soil skeleton,and fills the ***,when the proportion of UFC increases,the aggregate structure formed by a larger quantity of fine particles reduces the hydration rate and degree of cement hydration,making the UCS growth rate of cement-soil *** the peat soil environment,HA significantly weakened the UCS of cement-soil in both physical and chemical ***,UFC can mitigate the adverse effect of HA on cement-soil by its small particle size,high surface energy,and solid binding *** addition,FA has a positive effect on the UCS of cement-soil soaked for 28 days and 90 *** UFC addition could promote the enhancement effect of FA on cement-soil *** test results showed that cement hydration products increased significantly with the increase of UFC proportion,and cementation between hydration products and soil particles was *** size and connectivity of cement-soil pores were significantly reduced,thereby improving cement-soil structural integrity.

摘要：Design of a robust production facility layout with minimum handling cost （MHC） presents an appropriate approach to tackle facility layout problems in a dynamic volatile environment, in which product demands randomly change in each planning period. The objective of the design is to find the robust facility layout with minimum total material handling cost over the entire multiperiod planning horizon. This paper proposes a new mathematical model for designing robust machine layout in the stochastic dynamic environment of manufacturing systems using quadratic assignment problem （QAP） formulation. In this investigation, product demands are assumed to be normally distributed random variables with known expected value, variance, and covariance that randomly change from period to period. The proposed model was verified and validated using randomly generated numerical data and benchmark examples. The effect of dependent product demands and varying interest rate on the total cost function of the proposed model has also been investigated. Sensitivity analysis on the proposed model has been performed. Dynamic programming and simulated annealing optimization algorithms were used in solving the modeled example problems.

摘要：This paper presents the design of decentralized repetitive control （RC） for multi-input multi-output （MIMO） systems. An optimization method is used to obtain a RC compensator that ensures system stability and good tracking performance. The designed compensator is in the form of a stable, low order, and causal filter, in which the compensator can be implemented separately without being merged with the RC internal model. This will reduce complexity in the implementation. Simulation results and comparison study are given to demonstrate the effectiveness of the proposed design. The novelty of design is also verified in experiments on a 2 degrees of freedom （DOF） robot.

摘要：Conventional attractive magnetic force models (proportional to the coil current squared and inversely proportional to the gap squared) cannot simulate the nonlinear responses of magnetic bearings in the presence of electromagnetic losses,flux leakage or saturation of *** this paper,based on results from an experimental set-up designed to study magnetic force,a novel parametric model is presented in the form of a nonlinear polynomial with unknown *** parameters of the proposed model are identified using the weighted residual *** of the model identified were performed by comparing the results in time and frequency *** results show a good correlation between experiments and numerical simulations.

摘要：This paper presents a novel design of minimalist bipedal walking robot with flexible ankle and split-mass balancing *** proposed approach implements a novel strategy to achieve stable bipedal walk by decoupling the walking motion control from the sideway balancing *** strategy allows the walking controller to execute the walking task independently while the sideway balancing controller continuously maintains the balance of the *** hip-mass carry approach and selected stages of walk implemented in the control strategy can minimize the efect of major hip mass of the robot on the stability of its *** addition,the developed smooth joint trajectory planning eliminates the impacts of feet during the *** this paper,the new design of mechanism for locomotion systems and balancing systems are *** additional degree of freedom introduced at the ankle joint increases the sensitivity of the system and response time to the sideway *** efectiveness of the proposed strategy is experimentally tested on a bipedal robot *** experimental results provide evidence that the proposed strategy is feasible and advantageous.

摘要：The problem of active vibration control for uncertain linear structural systems with control forces input timedelay is investigated in this ***,the original structural equation is converted to a state-space model by utilizing the matrix ***,according to the obtained model and a special Lyapunov functional,a sufficient condition is achieved for the closed-loop system to be stable with a prescribed level of disturbance ***,in terms of solving these linear matrix inequalities（LMIs）,the state-feed controller is achieved to stabilize the structural system with the performance ‖z‖2<γ‖ω‖***,by introducing the rank-1 vector to describe the system uncertainties,the uncertain system description is obtained,and the stabilizing condition is extended to the uncertain ***,examples are given to show the effectiveness of the proposed methods.

摘要：Today, millions of electrocommunication, electric, medical, and industrial devices use battery. Batteries with long life and high energy density seem to be essential in medical, military, oil and mining, aerospace areas as well as conditions in which access is difficult and in situations where replacement or recharging of battery is *** this regard, the use of radiation energy resulting from radioactive materials and its conversion to electric energy can be effective in making batteries. In the present study,various Mo-99 radioisotope values with a half-life of 65.98 h were used as a soluble radioactive source in two materials of water and aqua regia. Then, by comparing the results of the Monte Carlo simulations program MCNPX for these two solutions, it was found that when the water is used instead of aqua regia(for idealization), the values of the superficial current of electrons, the volumetric flux of electrons, and the deposited energy in the volume containing the radioactive solution increased by 10.80, 4.10,and 13.80%, respectively. Also, the short-circuit current and energy conversion efficiency of this battery with a concentration of 0.01 molar, Mo-99 dissolved in the aqua regia are 0.79μA and 16.47%, respectively.

摘要：The finite element system CAPA-3D was utilized as the numerical simulation platform,two structural FE models of orthotropic steel bridge decks were set up,the static and dynamic FE simulations under different loading conditions were carried out,the special attention was given to identify the critical wheel load location,and the maximum tensile stress distribution and the variation of strain rate inside membrane *** result shows that the FE models are capable of simulating the realistic behavior of orthotropic steel *** distributions of strains and stresses inside the surfacing materials depend highly on wheel load level,wheel load frequency,wheel position,membrane bonding strength as well as the thicknesses and characteristics of surfacing *** maximum tensile stress of membrane layers is found around 0.4MPa,which coincides with the minimum requirement for the adhesive bonding strength of membrane material proposed by the standards NF P98-282and *** maximum membrane strain rate is found around 0.1,which is an important information that can be utilized for the characterization of membrane products.1tab,28figs,7refs.

摘要：Heat exchangers are widely used in the process engineering such as the chemical industries, the petroleum industries, and the HVAC applications etc. An optimally designed heat exchanger cannot only help the optimization of the equipment size but also the reduction of the power consumption. In this paper, a new optimization approach called algorithms of changes (AOC) is proposed for design and optimization of the shell-tube heat exchanger. This new optimization technique is developed based on the concept of the book of changes (I Ching) which is one of the oldest Chinese classic texts. In AOC, the hexagram operations in I Ching are generalized to binary string case and an iterative process, which imitates the I Ching inference, is defined. Before applying the AOC to the heat exchanger design problem, the new optimization method is examined by the benchmark optimization problems such as the global optimization test functions and the travelling salesman problem (TSP). Based on the TSP results, the AOC is shown to be superior to the genetic algorithms (GA). The AOC is then used in the optimal design of heat exchanger. The shell inside diameter, tube outside diameter, and baffles spacing are treated as the design (or optimized) variables. The cost of the heat exchanger is arranged as the objective function. For the heat exchanger design problem, the results show that the AOC is comparable to the GA method. Both methods can find the optimal solution in a short period of time.

摘要：The aim of this study is to define optimal tooth modifications, introduced by appropriately chosen head-cutter geometry and machine tool setting, to simultaneously minimize tooth contact pressure and angular displacement error of the driven gear （transmission error） of face-hobbed spiral bevel gears. As a result of these modifications, the gear pair becomes mismatched, and a point contact replaces the theoretical line contact. In the applied loaded tooth contact analysis it is assumed that the point contact under load is spreading over a surface along the whole or part of the ‘‘potential’’ contact line. A computer program was developed to implement the formulation provided above. By using this program the influence of tooth modifications introduced by the variation in machine tool settings and in head cutter data on load and pressure distributions, transmission errors, and fillet stresses is investigated and discussed. The correlation between the ease-off obtained by pinion tooth modifications and the corresponding tooth contact pressure distribution is investigated and the obtained results are presented.