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Simulations were made to test the effects of age and composition of red clover (Trifolium pratense) based leys on yield of two subsequent spring cereal crops, as well as nitrogen (N) uptake and soil mineral N content. The experimental plots in two trials were cropped for 2–3 years with spring cereals, or 1-, 2- or 3-year-old red clover based leys, followed by spring wheat and subsequent spring oats. CoupModel, a process oriented ecosystem model, was calibrated with measured values of above ground N uptake and soil mineral N contents from plots of cereal monoculture. Cereal N uptake was simulated for a 2 year period in cereals after leys. The calculations of N inputs in incorporated plant material of leys were also tested. Simulated N uptake in the above ground biomass generally agreed with the field data with default values of the model. Some parameters were increased in order to improve plant N uptake and keep the soil mineral N contents at the measured levels. The simulated soil mineral N contents were close to the measured values for surface layers and were more accurate than for deeper layers in the profile. However, the high simulated mineral N increase after harvest in one trial was not seen in field measurements, which remains difficult to explain. Most probably the C:N estimate for crop residues was set too low in the model, but calculated N input was on a reasonable level. These results show that further testing and adjusting of N dynamics in organic farming system using CoupModel should be continued.  相似文献   
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The expected emission spectra of nitrogen and oxygen high density plasma have been studied for different conditions. Expected nitrogen and oxygen plasma spectra at certain electron temperature range have been plotted. Suitable electron temperature ranges for nitrogen and oxygen plasma soft X-ray emission and extreme ultraviolet emission have been investigated. Numerical experiments confirm the possibility of developing nitrogen and oxygen plasma focus as a powerful X-ray radiation source for water-window X-ray microscopy, by selecting the working gas pressure, choosing corresponding design and operating parameters of the device. We have illustrated that the results obtained from XRAYFIL simulation could be used to provide spectroscopic information of the plasma focus simulated by Lee model.  相似文献   
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帘式涂布是一种低冲击预计量涂布方式,可用于纸和纸板的涂布、帘式涂布技术所产生的涂层为仿形涂层,因而能提供良好的纤维覆盖。在多层帘式涂布中,可以同时进行多层涂布。与单层帘式涂布相比,多层帘式涂布具有许多优点:投资成本更低、设计不同涂层性质更具灵活性、具有更大的涂布操作空间及涂层更薄等,  相似文献   
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Extracellular matrix (ECM) proteins are known to play a role in inflammatory and hyperplastic processes. Our aim in the present study was to study the distribution of tenascin (Tn), cellular fibronectins (cFn) and myofibroblasts around biodegradable poly-L/D-lactide (PLA) implants with monoclonal antibodies (MAb). Ethylene-oxide and gamma-irradiation sterilized PLA plate-type implants were inserted into the dorsal subcutaneous tissue of ten adult rabbits. Follow-up times were 4, 12, 16, 36 and 48 wk. Only some inflammatory cells were observed. In electron microscopy, a close coherence between the implant and the stromal tissue was seen. Immunoreactivity for Tn, cFn and -actin was detected as a distinct layer bordering the implant, regardless of the sterilization method for the first 36 wk. From week 36 onwards, Tn immunoreactivity was downregulated while cFn immunoreactivity still persisted. A moderate upregulation for myofibroblasts was seen on the week 48 specimens, when hydrolysation of PLA implant had started. The persistent content of myofibroblasts, Tn and cFn suggests a prolonged wound healing produced by PLA implants. The absence of Tn at the week 48 specimens suggests that cFn, rather than Tn may be needed for -actin-mediated contraction by myofibroblasts.  相似文献   
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3D objects with features spanning from microscale to macroscale have various applications. However, the fabrication of such objects presents challenges to additive manufacturing (AM) due to the tradeoffs among manufacturable feature resolution, maximum build area, and printing speed. This paper presents a projection-based AM process called hopping light vat photopolymerization (HL-VPP) to address this critical barrier. The key idea of HL-VPP is to synchronize linear scanning projection with a galvo mirror's rotation. The projector moves continuously at a constant speed while periodically rotating a one-axis galvo mirror to compensate for the projector's linear movement so synchronized hopping motion can be achieved. By this means, HL-VPP can simultaneously achieve large-area (over 200 mm), fast-speed (scanning speed of 13.5 mm s-1), and high-resolution (10 µm pixel size) fabrication. The distinguishing characteristic of HL-VPP is that it allows for hundreds of times lower refresh rates without motion blur. Thus, HL-VPP decouples the fabrication efficiency limit imposed by the refresh rate and will enable super-fast curing in the future. This work will significantly advance VPP's use in applications that require macroscale part size with microscale features. The process has been verified by fabricating multiple multiscale objects, including microgrids and biomimetic structures.  相似文献   
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