Investigation on a Non-cyanide Plating Process of Ni-P Coating on Magnesium Alloy AZ91D

In this research we presented a non-cyanide plating process of Ni-P alloy coating on Mg alloy AZ91D. By applying a new process flow of electroless nickel plating in which zinc coating is used as transition of Ni-P coating on Mg alloy AZ91D, the process of copper transition coating plated in the cyanides bath can be replaced. A new bath composed of NiSO4 was established by orthogonal test. The results show that zinc transition coating can increase the adhesion and protect the Mg alloy substrate from the bath corrosion. The optimal plating bath composition is NiSO4·6H2O 20 g/L, NaH2PO2·H2O20g/L and C6H8O7·H2O 2.5 g/L, and optimal bath acidity and optimal plating temperature are pH 4.0 and 95℃, respectively. The present process flow is composed of ultrasonic cleaning→alkaline cleaning→acid pickling→activation→double immersing zinc→electroplating zinc→electroless nickel plating→passivation treatment. The present non-cyanide process of electroless nickel plating is harmless to our surroundings and Ni-P coating on Mg alloy AZ91D produced by present process possesses good adhesion and corrosion resistance.

Self-Adaptive and Electric Field-Driven Protective Layer with Anchored Lithium Deposition Enable Stable Lithium Metal Anode

Lithium metal battery has great development potential because of its lowest electrochemical potential and highest theoretical capacity.However,the uneven deposition of Li^(+)flux in the process of deposition and stripping induces the vigorous growth of lithium dendrites,which results in severely battery performance degradation and serious safety hazards.Here,the tetragonal BaTiO3 polarized by high voltage corona was used to build an artificial protective layer with uniform positive polarization direction,which enables uniform Li^(+)flux.In contrast to traditional strategies of using protective layer,which can guide the uniform deposition of lithium metal.The ferroelectric protective layer can accurately anchor the Li^(+)and achieve bottom deposition of lithium due to the automatic adjustment of the electric field.Simultaneously,the huge volume changes caused by Li^(+)migration change of the lithium metal anode during charging and discharging is functioned to excite the piezoelectric effect of the protective layer,and achieve seamless dynamic tuning of lithium deposition/stripping.This dynamic effect can accurately anchor and capture Li^(+).Finally,the layer-modified Li anode enables reversible Li plating/stripping over 1500 h at 1 mA cm^(-2)and 50℃in symmetric cells.In addition,the assembled Li-S full cell exhibits over 300 cycles with N/P≈1.35.This work provides a new perspective on the uniform Li^(+)flux at the Li-anode interface of the artificial protective layer.

Ship hull plate processing surface fairing with constraints based on B-spline

The problem of ship hull plate processing surface fairing with constraints based on B-spline is solved in this paper. The algorithm for B-spline curve fairing with constraints is one of the most common methods in plane curve fairing. The algorithm can be applied to global and local curve fairing. It can constrain the perturbation range of the control points and the shape variation of the curve, and get a better fairing result in plane curves. In this paper, a new fairing algorithm with constraints for curves and surfaces in space is presented. Then this method is applied to the experiments of ship hull plate processing surface. Finally numerical results are obtained to show the efficiency of this method.

PREPARATION AND CORROSION RESISTANCE OF NiP/TiO_2 COMPOSITE FILM ON CARBON STEEL IN SULFURIC ACID SOLUTION

A NiP/TiO2 composite film on carbon steel was prepared by electroless plating and sol-gel composite process. An artificial neural network was applied to optimize the prepared condition of the composite film. Corrosion behavior of the NiP/TiO2 composite film was investigated by polarization resistance measurement, anode polarization, ESEM （environmental scanning electron microscopy） and EIS （electrochemical impedance spectroscopy） measurements. Results showed that the NiP/ TiO2 composite film has a good corrosion resistance in 0.5mol/L H2SO4 solution. The element valence of the composite film was characterized by XPS （X-ray photoelectron spectroscopy） spectrum, and an anticorrosion mechanism of the composite film was discussed.

Porous polymer electrolytes for long-cycle stable quasi-solid-state magnesium batteries

The development of applicable electrolytes is the key point for high-performance rechargeable magnesium batteries(RMBs).The use of liquid electrolyte is prone to safety problems caused by liquid electrolyte leakage.Polymer-based gel electrolytes with high ionic conductivity,great flexibility,easy processing,and high safety have been studied by many scholars in recent years.In this work,a novel porous poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)membrane is prepared by a phase inversion method.By immersing porous PVDF-HFP membranes in MgCl2-AlCl3/TEGDME(Tetraethylene glycol dimethyl ether)electrolytes,porous PVDF-HFP based electrolytes(PPEs)are formed.The PPE exhibits a high ionic conductivity(4.72×10^(-4) S cm-1,25℃),a high liquid electrolyte uptake of 162%,as well as a wide voltage window(3.1 V).The galvanostatic cycling test of Mg//Mg symmetric cell with PPE reveals that the reversible magnesium ion(Mg^(2+))plating/stripping occurs at low overpotentials(~0.13 V).Excellent long cycle stability(65.5 mAh g^(-1) over 1700 cycles)is achieved for the quasisolid-state RMB assembled with MoS2/C cathode and Mg anode.Compared with the liquid electrolyte,the PPE could effectively reduce the side reactions and make Mg^(2+)plating/stripping more uniformly on the Mg electrode side.This strategy herein provides a new route to fabricate high-performance RMB through suitable cathode material and polymer electrolyte with excellent performance.

Study on the vehicle license plate tilt correction

The shortage of current different approaches of the vehicle license plate(VLP) tilt correction is analyzed in the paper and a new rotary correction method put forward based on the former ways of the VLP tilt correction in the horizontal direction and the vertical direction Owing to the VLP tilt taking place in the vertical direction,the array of the image’s pixels of the same column is broken,and even different rows come into being superposition.The VLP tilt taking place in the horizontal direction,by which the array of the image’s pixels of the same row broken,and so much as different columns come into being superposition.

Opportunities and challenges of the Sponge City construction related to urban water issues in China

Waterlogging is one of the major water issues in most cities of China and directly restricts their urbanization processes.The construction of Sponge City is an effective approach to solving the urban water issues,particularly for the waterlogging.In this study,both the urban issues emerged at the stage of rapid urbanization in China and the demands as well as problems of Sponge City construction related with the water issues were investigated,and the opportunities and challenges for the Sponge City construction in the future were also proposed.It was found that the current stormwater management focused on the construction of gray infrastructures(e.g.,drainage network and water tank) based on the fast discharge idea,which was costly and hard to catch up with the rapid expansion of city and its impervious surface,while green infrastructures(e.g.,river,lake and wetland)were ignored.Moreover,the current construction of Sponge City was still limited to low impacted development(LID) approach which was concentrated on source control measures without consideration of the critical functions of surrounding landscapes(i.e.,mountain,river,wetland,forest,farmland and lake),while application of the integrated urban water system approach and its supported technologies including municipal engineering,urban hydrology,environmental science,social science and ecoscape were relatively weak and needed to be improved.Besides,the lack of special Sponge City plan and demonstration area was also a considerable problem.In this paper,some perspectives on Good Sponge City Construction were proposed such as the point that idea of urban plan and construction should conform to the integral and systematic view of sustainable urban development.Therefore,both the basic theoretical research and the basic infrastructure construction such as monitoring system,drainage facility and demonstration area should be strengthened,meanwhile,the reformation and innovation in the urban water management system and the education system should also be urgently performed.The study was expected to provide a deeper thinking for the current Sponge City construction in China and to give some of suggestions for the future directions to urban plan and construction,as well as urban hydrology discipline.