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Wa-ri heavy load railway is taken as the research object in the paper,the rail profiles are observed before and after grinding. Based on the wheel/rail contact wear theory and the finite element model of high-speed wheel/rail steady rolling contact established by the mixed Lagrangian/Eulerian method,the four kinds of railway grinding profile are contacted with LM wheels,the optimal rail profile was selected. Results show that,the profile 1 TQI and wear rate are the maximum,When the profile 1 contact with LM,the distribution of contact point pairs is relatively concentrated,equivalent conicity is largest,the mass flow density and wear power maximum are the biggest,wheel/rail wear is biggest. the profile 3 TQI and wear rate are the minimum,the contact point distribution between profile 3 and LM tread is good,equivalent conicity is least,the mass flow density and wear power maximum are the least. Therefore,only from the perspective of wear control,the research shows that the profile 3 is the optimal grinding profile.

The traditional methods of designing cam profile always leads to complicated calculation,low computational accuracy and efficiency. But by using Matlab programming language,the computational accuracy can be increased and the design period can be shortened in the process of solving and drawing cam profile.Firstly,the data points on the curve that are drawn in the Matlab can be derived. Secondly,a rough draft of cam profile is generated in Solid Works. Finally,the three- dimensional model of cam profile is created during the stretching process. This method is easy to operate and can greatly improve the design efficiency by quickly modifying the shape of cam profile according to the actual working conditions.

Rice–crab co-culture systems represent integrated agriculture–aquaculture systems developed in China over the last 30 years. The rice–crab co-culture area comprised approximately 1.386 × 105 hm2 in 2019. However, there is no specific feed designed for Chinese mitten crab (Eriocheir sinensis) cultured in this system until now. In this study, we investigated feed formulae for the nutritional requirements of Chinese mitten crab in this mode. The control group was not fed with any artificial feed (Co), and the experimental groups were fed with three different feeds of 15% (T15), 30% (T30), or 45% (T45) protein content, respectively. Growth performance variations in E. sinensis were investigated along with water quality, phytoplankton, zooplankton, aquatic vascular plants, and benthic animals in the paddy fields to determine the effect of crabs and their diet on the paddy ecosystem. Dietary protein levels had no significant effect on water quality. The biomass and species of phytoplankton, zooplankton, aquatic vascular plants, and zoobenthos in the paddy field were affected by crabs and their diet. Morphological parameters of crabs were significantly more pronounced in the high-protein group than in the other groups. However, the T45 diet negatively affected production by increasing feed costs, causing precocious puberty and inducing water eutrophication. In conclusion, adding a 15% protein compound feed can meet the nutritional needs of crabs, reduce culture costs, and improve water quality. The discharged water had low ammonia nitrogen and nitrite content and no eutrophication occurred, so the water could be recycled. These findings provide a scientific reference for supporting rice and fish co-cultivation. [ABSTRACT FROM AUTHOR]

Using the three-dimensional classical ensemble approach, we theoretically investigate the nonsequential double ionization of argon atoms in an intense laser field enhanced by bowtie-nanotip. We observe an anomalous decrease in the double ionization yield as the laser intensity increases, along with a significant gap in the low momentum of photoelectrons. According to our theoretical analysis, the finite range of the induced field by the nanostructure is the fundamental cause of the decline in double ionization yield. Driven by the enhanced inhomogeneous field, energetic electrons can escape from the finite range of nanotips without returning. This reduces the possibility of re-scattering on the nucleus and imprints the finite size effect into the double ionization yield and momentum distribution of photoelectrons in the form of yield decline and a gap in the photoelectron-momentum distribution.

The carrier-envelop-phase (CEP) dependence of nonsequential double ionization (NSDI) of atomic Ar with few-cycle elliptically polarized laser pulse is investigated using 2D classical ensemble method. We distinguish two particular recollision channels in NSDI, which are recollision-impact ionization (RII) and recollision-induced excitation with subsequent ionization (RESI). We separate the RII and RESI channels according to the delay time between recollision and final double ionization. By tracing the history of the trajectories, we find the electron correlation spectra as well as the competition between the two channels are sensitively dependent on the laser field CEP. Finally, control can be achieved between the two channels by varying the CEP.