Impact craters serve as recorders of lunar evolutionary history, and determining the stratigraphic ages of craters is crucial. However, the age of many craters on the Moon remains undetermined. The morphology of craters is closely related to their stratigraphic ages. In the study, we systematically and quantitatively analyzed seven morphological parameters of 432 impact craters with known stratigraphic ages (Copernican, Eratosthenian, Imbrian), including crater depth, wall width, wall height, rim height, irregularity, volume, and roughness, as well as rock abundance. The study provided a range of morphological parameters for craters from the Copernican, Eratosthenian, and Imbrian. Additionally, we derived power law relationships between five morphological parameters and crater diameter, excluding irregularity and roughness. Furthermore, the transitional crater diameters from simple to complex crater morphology were determined for the Copernican and Eratosthenian, approximately 13 km and 15 km, respectively. These results suggest systematic differences in the lunar regolith in different stratigraphic ages. For impact craters of the same diameter, as crater age increases, irregularity tends to be greater, while crater depth, wall width, wall height, rim height, volume, roughness, and rock abundance tend to be smaller. Therefore, in cases where the diameter is determined, the actual values of morphological parameters and rock abundance can be used to constrain the stratigraphic age information of craters of an unknown age.
As complex ceramic multicomponent materials, the lunar regolith and minerals still challenge people on onsite utilization technology limited to the lunar surface environment. In this paper, we investigate the suitability of lunar regolith simulants and ilmenite powders for 3D printing (aka Additive Manufacturing) of hypothetical brick aimed at lunar habitat construction. The first generation of laser 3D printing equipment (Lunar 1.0) for our experiments has been designed and assembled, which is suitable for selective laser sintering (SLS) process out of many kinds of ceramic powders to manufacturing samples with different geometrical shapes. The lunar regolith simulants and ilmenite powders are demonstrated obvious spectral absorbance from ultraviolet to near-infrared spectra, which are successfully performed during the SLS process in Lunar 1.0. The 3D printing technologies are constantly improved by adjusting the parameters of laser process and mechanical movement. The morphological features of 3D printed samples, including surface and porosity are investigated by using SEM. The evaluation of size and micro-hardness tests are also conducted to reveal the printing qualities of samples. The EDS and XRD results characterize the elements and components of 3D printed samples. Obviously, the strong heating process by laser source in Lunar 1.0 has a great impact on materials, because the complex multicomponent materials and solid state reaction in high temperature by SLS process for regolith simulants and ilmenite. However, this influence of heat treatment by laser source is quite different from continuously thermal treatment for ceramics such as normal high temperature furnace. In the future, the research for 3D printing of lunar regolith simulants and ilmenite powders for hypothetical brick in vacuum and low gravity will carry out for approaching the extreme manufacturing environment on lunar surface.
Objective To explore more reasonable way of early post-operative effect of enteral nutrition fluids support for colon cancer.Methods A total of 86 case of colon cancer were selected and assigned to enteral nutrition group(EN n=45)and parenteral nutrition group(PN n=41)randomly.Parameters inclu ding the body wetght,IsA,IgM,lymphocyte,human serum prealbumin and albumen were monitored on three days before operation,the fifth,and eighth days after operation.Results The IgA,IgM,lympho cyte,human serum prealbumin and albumen levels of patients in EN group were much higher than that in PN group on the fifth and eighth days after operation(P＜0.05).Also IgA,lgM levels of EN group patients were almost higher than that in PN group on eighth day after operation(P＜0.01).Concusions It showed that to perform enteral nutrient supports for patients of colon cancer during early post-operative could increase their gut immunity after operation and reduce the complications and raise human serum prealbumin and albu men of them for their body recovery.
Key words:
colon cancer; early post-operative complications; enteral nutrient fluids
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