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Taking 7-year-old apple trees (Hanfu) as the test material, an experiment with three irrigation levels including high water (W以陕北山地7年生‘寒富’苹果树为试验材料,设置3个灌水水平[高水(W

Film hole irrigation is a relatively low cost and high efficiency irrigation method, which can significantly improve the efficiency of agricultural water use. In order to establish the quantitative model of film hole irrigation between cumulative infiltration and the wetting body and the irrigation volume model of crops, the infiltration process and wetting body characteristics of four different soils (Xi’an silt loam, silt, silt loam and loam) were studied in laboratory experiments and numerical HYDRUS simulation experiments. The relationship between cumulative infiltration and wetting body radius was established using a mathematical method, and a crop irrigation volume model was proposed based on the root distribution and the required water content of different crops. The experimental results showed that the shape of the wetting body of film hole irrigation is approximately half of the rotating ellipsoid, and the curve shape of the wetting front can be expressed using an elliptic equation. From the center of the film hole to the surface of the wetting front, the soil water content of the wetting body gradually decreases, and the change rate of water content gradually increases, reaching its maximum value near the wetting front. Furthermore, the distribution of water content in the wetting body can be accurately expressed using an elliptic curve equation. The cumulative infiltration of film hole irrigation is proportional to the third power of the equivalent radius of the wetting body, and the equivalent radius is equal to the geometric mean of the horizontal and vertical migration distances of the wetting front. In addition, based on the distribution of crop roots and the demand of crop roots on soil water content, the irrigation model of crops was established. This study provides a theoretical basis for the calculation of the irrigation volume for film hole irrigation under the condition of experiment, and has a guiding significance for the field experiment and application of film hole irrigation in different crops in future.

This paper is mainly on the research of squeeze casting production automobile air conditioner front cover FS170C, due to the development and optimization of the part in the production process, design and manufacture of low cost mould, the rules of structure and properties of castings is lack of corresponding research, seriously affected the development and market competition ability of the air conditioning compressor front cover. In order to solve the above problems, and to provide reference data and process scheme is necessary, this study to optimize the design of squeeze casting technology of the front cover of the air conditioner, finalized a most reasonable extrusion casting scheme, namely the gating system is more suitable and exhaust system design, and the squeeze casting process parameters, in this scheme next, carries on the mold design, production of squeeze casting of high quality.

Through film hole irrigation test-pit experiments,the effects of different irrigation treatments on water consumption,growth characteristics and maize yield were studied.The result showed that the jointing stage and heading stage were the key stages of water requirement of maize.Water consumption increased with the increased irrigation quota at the same number of irrigation.Effect of irrigation treatment on maize biological index was significant in less irrigation times and less irrigation quota.Water production efficiency increased 23.3% and yield increased 15.9% under film hole irrigation than that of border irrigation.Water consumption of the maximum yield was 3410m3/hm2 under film hole irrigation.

Heat-resistant aluminum alloy because of its low density, low price, good heat resistance and corrosion resistance, has been widely used in aviation, aerospace, weapons and other industrial fields. In this paper, preparation of Al-Fe-V-Si heat-resistant aluminum alloy materials is used in the RS/PM process, and studied the influence law of effect of alloy composition on the microstructure and mechanical properties of heat-resistant aluminum alloy. The results show that, Fe, V, Si element content and Fe/V ratio has great effect on the microstructure and mechanical properties. When the Fe content is too low, the content of Al12(Fe, V)3Si phase is less. Mechanics to improve material properties cannot be maximum; if the content of Fe is excessive, the strength of the material do not increase, but decrease the plastic. The addition of V element can be stabilized in Al12(Fe, V)3Si Si phase; and the addition of Si can inhibit the second-phase dispersion phase coarsening and decomposition, increase the high temperature stability of materials; Fe/V ratio affects the coarsening rate of second-phase particles, thus affecting the thermal stability of materials.

With the growth of population, shortage of water resources, natural disasters, climate change, serious shortage of land resources and the development of urbanization and industrialization and impacts of other unfavorable factors, China's grain security issue has become a focus of public concern. Through the Chinese population quantity analysis and forecast of 2020 and 2030 the total demand of grain, comparison between total demand and current level of food production, China's grain problem is facing tremendous pressure. Water conservancy is the lifeline of agriculture and irrigation has great potential for grain production guarantee. Results for food safety in China made the following responses: First, the rational use of water resources, improve the efficiency of irrigation and grain yield per unit area. Second, multiple sectors such as agriculture, meteorology, soil, make a good combination of multiple disciplines for food security. Third, increase the peasants' production enthusiasm. Last, scientific and technological progress is the guarantee of grain production. In General, the issue of food security is national security, social stability, a top priority. The combination of our country's water resources crisis, limited rational development of agricultural water resources, improve the efficiency of irrigation, which will provide a guarantee for China agricultural water crisis, alleviating the shortage of water resources and increasing food safety assurance.

High strength aluminum alloy is mainly traditional alloy hypoeutectic composition, containing the solid solubility of alloy elements atomic fraction is greater than 2, and reached the alloy trengthening effect by the precipitation of intermetallic compounds in the process of aging. But in more than 150°C, the precipitated phases coarsening, the material performance dramatically, thus limiting its use scope. In the preparation process, the planar flow casting process will melt thrown by 35-80um thick slices with, because the cooling speed can reach 105K/s the process of melt, so the microstructure is very fine, after extrusion. Grain size of about 1um, precipitates spherical and uniform distribution, the size of about 50nm, Al12(Fe,V)3Si phase coarsening rate is low, so the alloy has comprehensive mechanical performance and excellent high temperature stability.

This paper emphasis has researched the effect of particles scattering, surrounding thickness, heat treatment temperature and etc on microstructure, mechanics properties and macrostructure under different electric field of Ni/TiO2, Ni/TiO2/PAn Particles ER fluid, It is found that particles scattering, surrounding thickness, heat treatment temperature have major effect on shear stress and chain of particles.

In order to obtain the directional microstructure of different supersaturation and growing velocity, three simulations is calculated with different initial temperature. When the initial temperature is 1576K, and the supersaturation and growing velocity are smaller. The average space length of columnar crystals is bigger, and microsegregation is smaller. when the initial temperature is 1574K, the supersaturation and growing velocity increase. The average space length of columnar crystals decreases, and microsegregation increase; when the initial temperature falls to 1566K, the supersaturation and growing velocity reach 1.176 and 3.238 cm per second. The microsegregation decreases rapidly. The average space length of columnar crystals is the smallest. The solute curve of columnar crystal is like a “U” figure. When the growing velocity is bigger than VA, the phenomenon of solute trapping takes place.

In this study W was found to have strong effects on solidification structure of the binary alloy. Based 0.5 W0、W0 and 1.5W0 base W0, three conditions with free energy base W equal to 0.5 W0, W0 and 1.5W0 respectively were computed. The results showed that the variation of energy base contributed a lot to the development of side branches of equiaxed dendrite structures, the lower W, the more developed side branches, the higher W, the more restrained side branches. Furthermore, the effects of boundary layer thickness δ on solidification structures were also studied. It is found that when the layer thickness δ is as small as Δx/0.94, computational errors occurred at the base of the dendrite and when the layer thickness δ is as big as Δx/0.54, some irreal phenomena, such as coarsened dendrite trunks and maladjusted side branches, could be caused. Further study on space step Δx showed that bigger space steps made higher computational errors. It is given that the relationships among phase-field perturbation, space step and solidification structure.

According to the application style and technical characteristics in surface irrigation and subsurface irrigation, we analyze the function of flow adaptive for emitter based on understanding the development present situation of subsurface drip irrigation system and emitter. At the theory of soil moisture, we put forward a specific measures about realizing the capacity adaptive function to emitter, that is, a kind of emitter with flow adaptive function for subsurface drip irrigation has been designed. This emitter takes the soil negative pressure as power, the soil moisture as control condition, the actual water requirement of crop as the final control object, and its drip status is controlled by the changes of elastic membrane in it. So the emitter can reflect the change of soil moisture automaticly and realtimely, with obvious function of self-adjusting current capcacity.