摘要：Allelopathic effects of submerged macrophytes against algae are affected by many environmental factors which can only be measured one by one by traditional methods. Box-Behnken design of response surface methodology was used to optimize three environmental factors （temperature, light intensity and total dissolved solids） of allelopathic effects of Potarnogeton pectinatus against Microcystis aeruginosa at the same time. By solving the regression equation and analyzing the response surface contour plots, the optimal conditions of the relatively inhibitory rate of Microcystis aeruginosa were that the temperature was 23℃, the light intensity was 2 700 lx and the total dissolved solids were 4 415 mg/L. Under these conditions, the optimal value of relatively inhibitory rate of Microcystis aeruginosa was 81.9%. According to validation experiments, the results of analysis indicated that the experimental values fitted well with the predicted ones.

摘要：Based on a level set model and the homogenization theory, an optimization al- gorithm for ?nding the optimal con?guration of the microstructure with speci?ed properties is proposed, which extends current research on the level set method for structure topology opti- mization. The method proposed employs a level set model to implicitly describe the material interfaces of the microstructure and a Hamilton-Jacobi equation to continuously evolve the ma- terial interfaces until an optimal design is achieved. Meanwhile, the moving velocities of level set are obtained by conducting sensitivity analysis and gradient projection. Besides, how to handle the violated constraints is also discussed in the level set method for topological optimization, and a return-mapping algorithm is constructed. Numerical examples show that the method exhibits outstanding ?exibility of handling topological changes and ?delity of material interface represen- tation as compared with other conventional methods in literatures.

摘要：A materials design tool for developing Pb-free soldering alloys in electronic package was developed based on comprehensive experimental data of phase equilibria and thermodynamic properties data accumulated with the CALPHAD (calculation of phase diagrams) method and contains 10 elements,namely,Ag,Au,Bi,Cu,In,Ni,Sb,Sn,Zn and *** can handle the calculation of phase diagrams in all combinations of these elements and all composition *** addition,based on this tool,the liquidus,solidus,phase fractions and constitutions,equilibrium and non-equilibrium solidification behavior,surface tension and viscosity of liquid,diffusion reactions and microstructural evolution,*** be *** examples of the calculation and application of this tool are *** design tool is expected to be a powerful tool for the development of Pb-free solders,as well as for promoting the understanding of the interfacial phenomena between Cu substrate and Pb-free solders in electronic packaging technology.

摘要：As children mature, bike products for children in the market develop at the same time, and the conditions are frequently updated. Certain problems occur when using a bike, such as cycle overlapping, repeating function, and short life cycle, which go against the principles of energy conservation and the environmental protection intensive design concept. In this paper, a rational multi-function method of design through functional superposition, transformation, and technical implementation is proposed. An organic combination of frog-style scooter and children’s tricycle is developed using the multi-function method. From the ergonomic perspective, the paper elaborates on the body size of children aged 5 to 12 and effectively extracts data for a multi-function children’s bike, which can be used for gliding and riding. By inverting the body, parts can be interchanged between the handles and the pedals of the bike. Finally, the paper provides a detailed analysis of the components and structural design, body material, and processing technology of the bike. The study of Industrial Product Innovation Design provides an effective design method to solve the bicycle problems, extends the function problems, improves the product market situation, and enhances the energy saving feature while implementing intensive product development effectively at the same time.

摘要：To obtain a good drivability and high efficiency of the micro-electric vehicle, a new driving in-wheel motor design was analyzed and optimized. Maxwell software was used to build finite element simulation model of the driving in-wheel motor. The basic features and starting process were analyzed by field-circuit coupled finite element method. The internal complicated magnetic field distribution and dynamic performance simulation were obtained in different positions. No-load and load characteristics of the driving in-wheel motor was simulated, and the power consumption of materials was computed. The conformity of the final simulation results with the experimental data indicates that this method can be used to provide a theoretical basis to make further optimal design of this new driving in-wheel motor and its control system, so as to improve the starting torque and reduce torque ripple of the motor. This method can shorten the development cycle of in-wheel motors and save development costs, which has a wide range of engineering application value.

摘要：During oil-gas well drilling and completion, downhole tools and apparatus should be conveyed to the destination to complete a series of downhole works. Downhole tractors have been used to convey tools in complex wellbores, however a very large tractive force is needed to carry more downhole tools to accomplish works with high efficiency. A novel serial active helical drive downhole tractor which has significantly improved performance compared with previous work is proposed. All previously reported helical drive downhole tractors need stators to balance the torque generated by the rotator. By contrast, the proposed serial downhole tractor does not need a stator; several rotator-driven units should only be connected to one another to achieve a tractive force multifold higher than that was previously reported. As a result, the length of a single unit is shortened, and the motion flexibility of the downhole tractor is increased. The major performance indicators, namely, gear ratio, velocity, and tractive force, are analyzed. Experimental results show that the maximum tractive force of a single-unit prototype with a length of 900 mm is 165.3 kg or 1620 N. The analysis and experimental results show that the proposed design has considerable potential for downhole works.

摘要：A biosensor device, built from graphene nanoribbons （GNRs） with nanopores, was designed and studied by first- principles quantum transport simulation. We have demonstrated the intrinsic transport properties of the device and the effect of different nucleobases on device properties when they are located in the nanopores of GNRs. It was found that the device＇s current changes remarkably with the species of nucleobases, which originates from their different chemical compositions and coupling strengths with GNRs. In addition, our first-principles results clearly reveal that the distinguished ability of a device＇s current depends on the position of the pore to some extent. These results may present a new way to read off the nucleobases sequence of a single-stranded DNA （ssDNA） molecule by such GNRs-based device with designed nanopores

摘要：Resistive Plate Chamber （RPC） modules will be used as one part of the cosmic muon veto system in the Daya Bay reactor neutrino experiment. A total of 189 RPC modules will cover the three water pools in the experiment. To achieve track reconstruction and high efficiency, each module consists of 4 layers, each of which contains two sizes of bare chambers. The placement of bare chambers is reversed in different layers to reduce the overlapping dead areas. The module efficiency and patch emciency were studied both in simulation and test of the data analysis. 143 modules have been constructed and tested. The preliminary study shows that the module and patch 3 out of 4 layers efficiency reaches about 98%.

摘要：A conceptual design of using novel telescopic piles to position a multi-modular very large floating structure(VLFS),which is supposed to be severed as a movable floating airport,is *** telescopic piles can automatically plug in the soil to resist the environmental loads and pull out from the soil to evacuate or move on to the next operational *** feasibility demonstration of the conceptual design includes two parts:function verification and structure *** the latter part of the conceptual design,a time-domain structural analysis is firstly conducted by using Abaqus *** simulation results suggest that the preliminary structure scheme is not optimum due to the insufficient structure utilization,although both structure safety of the piles and positioning accuracy are *** realize a cost reduction of construction and installation,a Genetic Algorithm-Finite Element Analysis(GA-FEA)method is employed to perform structural *** optimization,31 percent of the weight of each pile is reduced and higher structure utilization is *** difference of the self-weight and allowable buoyancy of a single module(SMOD)of a semisubmersible-type VLFS is much larger than the weight of the *** with the function verification in our previous work,the conceptual design of using the novel telescopic pile to position VLFS is demonstrated to be feasible.

摘要：This paper focuses on a new design of a down-conversion mixer for a low-IF wideband *** on the folded structure and differential multiple gated transistor（DMGTR） technique,a novel quadrature mixer with a high conversion gain,a moderate linearity,and a moderate NF is *** mixer is designed and implemented in a 0.18-m CMOS process,and can operate in a frequency range from 150 kHz to 1.5 *** circuit performance is confirmed by both simulation and measurement *** measurement results exhibit a peak conversion gain of 13.35 dB,a high third order input referred intercept point of 14.85 dBm,and a moderate single side band noise figure of 10.67 ***,the whole quadrature mixer core occupies a compact die area of 0.122 *** consumes a current of 3.96 mA（excluding the output buffers） under a single supply voltage of 1.8 V.