基于计算机视觉的番茄颜色检测研究

以提高番茄人工分拣效率为目的,利用计算机视觉技术,建立番茄检测试验平台,将采集的番茄图像转化为HIS颜色模型,进行二值化,研究番茄成熟度。文章对番茄规定的四个等级进行分级,其分级的结果为:超优、优、良和未成熟的判断正确率分别为80%、60%、40%和80%,总的判断正确率为65%。     

Synthesis and Bioactivity of 5-Substituted-2-furoyl Diacylhydazide Derivatives with Aliphatic Chain

A series of 5-substituted-2-furoyl diacylhydazide derivatives with aliphatic chain were designed and synthesized. Their structures were characterized by IR, ¹H NMR, elemental analysis, and X-ray single crystal diffraction. The anti-tumor bioassay revealed that some title compounds exhibited promising activity against the selected cancer cell lines, especially against the human promyelocytic leukemic cells (HL-60). Their fungicidal tests indicated that most of the title compounds showed significant anti-fungal activity. The preliminary structure-activity relationship showed that the aliphatic chain length and differences in the R² group had obvious effects on the anti-tumor and anti-fungal activities. The bioassay results demonstrated that the title compounds hold great promise as novel lead compounds for further drug discovery.     

市政管线隧道下穿既有桥梁关键技术研究

目前国内大城市大型市政管线常采用浅埋暗挖式隧道施工,笔者结合北京市蒲黄榆路热力管线隧道下穿南三环刘家窑桥工程实例,对市政管线隧道下穿既有桥梁关键技术进行了分析研究(主要包括:既有桥梁现况检测评估、隧道施工对桥梁结构安全影响分析、监控量测内容及控制指标确定、重点施工工艺分析等),该研究对类似工程有一定的借鉴作用。     

Buckwheat trypsin inhibitor enters Hep G2 cells by clathrin-dependent endocytosis

Recombinant buckwheat trypsin inhibitor (rBTI) was studied to evaluate if it could enter cancer cells and to determine the mechanism. Fluorescein isothiocyanate-labelled buckwheat trypsin inhibitor (FITC-BTI) entered Hep G2 cells in a concentration-dependent manner. FITC-BTI colocalised with labelled transferrin (Tf) in the punctate structure, implying that rBTI enters Hep G2 cells by clathrin-dependent endocytosis. Incubation of Hep G2 cells with different chemical inhibitors abolished diffuse, but not punctate fluorescence, thus indicating that membrane potential plays a critical role in this process. Impairment of clathrin-mediated endocytosis by RNAi with clathrin heavy chain greatly reduced or completely abolished both diffuse and punctate fluorescence, further supporting a theory of a single route of endocytosis. Consistent with our working hypothesis, Hep G2 cells which were arrested in the M phase did not show any vesicular or diffuse FITC-BTI. We conclude from these results that both endocytosis and membrane potential are required for rBTI entry into Hep G2 cells.     

Effect of Fe‐Contained Species on the Preparation of α‐Si3N4 Fibers in Combustion Synthesis

Herein, Si₃N₄ powders of comparatively high α‐phase but with distinct morphologies, especially α‐Si₃N₄ fibers, were successfully prepared by a developed combustion synthesis (CS) strategy. Different proportions of Fe and Fe₂O₃ were innovatively doped in reactants as additives to control the phase constitution and their relative percentage, as well as morphologies of final microstructures. One step further, the effects of Fe‐contained impurities on the CS process were rationally proposed and verified based on a series of meticulous designed experiments. It turns out that two contradictory effects of metal Fe on the formation of α‐Si₃N₄ synergistically play vital roles in the CS reaction. The existence of metal Fe can accelerate the crystallization of the amorphous SiO₂, which act as protection layer outside the Si powders and subsequently promote the generation of gaseous SiO. These gaseous SiO easily reacts with N₂ and eventually form α‐Si₃N₄. On the other hand, the formation of β‐Si₃N₄ will be promoted by the assistance of some liquid phases, and in this case, they mainly come from the reaction between Fe and Si. For this study, when the content of doped Fe is below 2 mol%, the prior effect on promoting α‐phase content is pronounced. Otherwise, the latter dominates the CS process as the content of Fe additive is further increased above 2 mol%. In a different way, Fe₂O₃ mainly encourages the formation of β phase through the large amount of newly generated liquid phases, although the reduced SiO₂ and Fe may still promote the α/β ratio on some extent.     

Antibacterial and biological properties of silver-loaded coralline hydroxyapatite

The antibacterial and biological properties of silver-loated coralline hydroxyapatite (Ag-CHA) as a new antibacterial implant material were investigated in this study. Compared to other antibiotic and chemical bactericidal agents, Ag⁺ does not bring bacterial resistance to drugs and has less toxicity. The porous CHA was formed by hydrothermal exchange, then Ag⁺ was loated onto CHA through ion exchange and adsorption. The microstructure and composition of Ag-CHA were characterized by scanning electron microscopy (SEM), Rutherford backscattering spectrometry (RBS), and energy dispersive spectrometry (EDS). Antibacterial activity of Ag-CHA on the clinical strains of Escherichia coli (E. Coli) and Staphylococcus aureus (S. Aureus) was evaluated by the flat plate diffusion method. The antibacterial activity of Ag-CHA was found to be correlated with the concentration of Ag⁺ in a dose-dependent manner, which indicated that the optimal antibacterial and biocompatible effects of Ag-CHA could be obtained with Ag⁺ concentrations from 5×10⁻⁵ to 1×10⁻⁴ mol/L.     

富水地层下双液注浆技术

结合工程实例,阐述了双液注浆的原理、材料及技术特点,依据双液注浆的使用范围,对双液浆的配比与注浆机具进行了介绍,最后提出了双液注浆的检测方法,为同类工程提供借鉴。     

承钢1780线精轧机的减速机螺栓断裂分析

介绍了对承钢1780生产线F1精轧机减速机输入轴固定螺栓和F3精轧机减速机地脚螺栓断裂的断口形貌.对其最大承受力和直径进行了计算,对其微观组织进行了分析,找到了这两起螺栓断裂失效的原因,给出了相应的解决措施.     

Evaluation of PHBHHx and PHBV/PLA fibers used as medical sutures

Two types of fibers were prepared by using bio-based materials: a mono-filament made from poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) and a multi-filament made from poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and polylactic acid (PLA) blend. The two fibers were evaluated for mechanical properties, biocompatibility and degradability for the potential application as medical sutures. The PHBHHx fiber showed remarkable biocompatibility by H.E. Stainning, with very little impact to the surrounding tissues. The degradation of the fiber was observed by SEM after implantation for 36 weeks, and the major degradation product was detected after 96 weeks. Consistently, the PHBHHx fiber maintained more than half of the mechanical properties after 96 weeks. The other fiber was prepared by twisting PHBV/PLA blend strands to a bunch, and showed high biocompatibility and relatively high degradability. The bunched structure loosed after 36 weeks of implantation. These low-cost and easily prepared fibers have great potential in medical applications, since they could avoid the formation of fibrous capsule, reduce the size of scar, and degrade into non-toxic and even beneficial products.     

Notch effect on the tensile properties of cold-rolled Ni3Al foils

Notch effect on the tensile properties of the Ni₃Al foils has been investigated as a function of notch geometry and foil’s thickness. Tensile tests along the rolling direction (RD) and the transverse direction (TD) showed that notch weakening occurred with introduce of a notch. Plastic deformation was observed locally at notch root and the effective stress concentration factor (k_e) was much lower than the theoretical stress concentration factor (K_t). Contrary to the anisotropy in fracture stress along the RD and the TD, k_e fell on the same curve. Crack initiation mechanism was different between two tensile directions, that is, cracks initiated along the shear band in the RD tension, while cracks initiated homogenously on the slip planes in the TD tension.