Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《材料研究学报》
Abstract： The friction and wear properties of graphene (GP) as a lubricant additives were investigated by means of a UTM-2 tribometer via a ball on plate contact reciprocating sliding. The molecular structure and morphology of graphene nano sheets were characterized by TEM, SEM, XRD, IR and Raman spectroscopy. The friction and wear test was performed with lubricant of PAO4 oil without and with addition of 0.01% graphene (GP) respectively at different temperatures for the textured bronze with different ratio of textured area. The results show that GP can effectively reduce the friction and wear, especially at 60℃ and 100℃. For the simple PAO4 oil, the bronze with untextured surface exhibits the lowest friction coefficient and wear rate at 60℃ and 100℃; whilst, with the increasing ratio of the textured area, the friction coefficient and wear rate increase. For graphene-containing PAO4 lubricating oil, the friction coefficient is lower for the bronze with 5% textured area, while higher for those with 20%; the wear rate is lower for the bronze with 10% textured area.
Subjects: Mechanics >> Applied Mechanics submitted time 2023-03-20 Cooperative journals: 《应用力学学报》
Abstract： In micro-milling , due to the limitation of machining allowance , the feed per tooth of the millingcutter is very small or even smaller than the internal grain size of the material. When the cutting is carriedout between the grains , it will cause discontinuity in cutting , which will sharply increase the chatter duringthe milling process , cause the quality of the processed surface to decrease , and seriously affect the fatiguelife and performance of the micro-parts. Based on the Voronoi diagram , the paper establishes a polycrystal-line geometric model.'Through the method of simulation and experimental verification , the influence law ofthe cutting edge arc radius , cutting depth and grain size on the residual stress of the machined surface isstudied in detail, and a multiple linear regression model is established.Perform a significance test. The micro-milling experiment was carried out on the superalloy GH4169 with different grain sizes after heattreatment. The residual stress value of the machined surface in the feed direction of the workpiece was meas-ured by X-ray diffraction method , and the experimental value was compared with the predicted value to veri-fy the residual stress prediction model Accuracy. 'The results show that the error distribution is 2.18%o-7.35% ,not more than 10% , which can indicate that the prediction model of residual stress is more accurate.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-11-29 Cooperative journals: 《计算机应用研究》
Abstract： The sponge function uses shorter keys and initial vectors, so it is used as a new pseudo-random generator structure. This paper proposed a fast pseudo-random sequence generation method based on spongy function in combination with the coding theory, to solve the problems of low efficiency and slow speed of 2SC (sponge code-based stream cipher) pseudo-random sequence generation method proposed by Meziani et al. uses a generic state transformation which is reducible to the Regular Syndrome Decoding problem(RSD) , but has better computational characteristics than the regular encoding. Theoretical analysis and experimental results show that the pseudo-random sequence generator preserves the characteristics of sponge function, but it improved the efficiency greatly. For the security level of 160bits, its 5 times faster than the original scheme. At the same time, NIST statistical test, sequence balance and cross correlation test results show that the generated pseudo-random sequence has good random characteristics.
Subjects: Biology >> Zoology submitted time 2017-10-23 Cooperative journals: 《动物营养学报》
Abstract：茶多酚（TP）是一种从绿茶和红茶中提取的纯天然复合物，具有清除自由基、防止DNA受损、调节细胞内抗氧化防御系统及抗癌等生物学功能。本文系统地对TP的组成成分、抗氧化作用、对丝裂原活化蛋白激酶-核因子酶2相关因子2-抗氧化反应原件（MAPK-Nrf2-ARE）信号转导通路的调控及其相关机制进行综述。
Subjects: Biology >> Zoology submitted time 2017-10-23 Cooperative journals: 《动物营养学报》
Abstract：Kelch样环氧氯丙烷相关蛋白–核因子E2相关因子2–抗氧化反应元件（Keap1-Nrf2-ARE）信号通路是机体细胞抵制氧化应激损伤和异生物质损伤最为重要的一种防御机制，且该通路与炎性疾病包括癌症、神经变性疾病、心血管疾病、衰老等密切相关。Nrf2信号的激活可诱导与ARE相关基因的各种解毒酶、抗氧化防御酶和抗氧化蛋白酶的表达的转录调控，且调控Keap1-Nrf2-ARE信号通路已成为预防和治疗氧化应激相关疾病和炎性疾病的一个强有力的靶目标。该文重点综述了氧化应激、Keap1-Nrf2-ARE信号通路在抗氧化应激中的作用及相关的调控剂。
Subjects: Biology >> Zoology submitted time 2017-10-10 Cooperative journals: 《动物营养学报》
Abstract：本试验旨在研究混合植物油替代鱼油对中华绒螯蟹成体雄蟹性腺发育、脂质代谢、抗氧化及免疫性能的影响。采用混合植物油（豆油：菜籽油=1:1）替代不同水平（0、25%、50%、75%和100%）鱼油，制成5种等氮等脂的育肥饲料（粗蛋白质和粗脂肪含量分别为39.5%和14.0%），分别记为饲料1#、2#、3#、4#和5#），对5组成体雄蟹（每组4个重复，每个重复25只）进行了为期60 d的室外池塘饲养试验。结果显示：1）混合植物油替代不同水平鱼油对雄蟹性腺指数（GSI）及肝胰腺指数（HSI）均无显著影响（P>0.05）。2）饲料4#组肝胰腺中甘油三酯（TG）含量最低，其余各组肝胰腺中TG及总胆固醇（TC）含量均无显著差异（P>0.05）；除游离胆固醇（FC）和高密度脂蛋白胆固醇（HDL-C）含量外，饲料2#组血清中其余各项脂质代谢指标均显著高于其他组（P0.05）外，饲料1#组的总抗氧化能力（T-AOC）、过氧化物酶（POD）活力和丙二醛（MDA）含量均显著高于其他各组（P0.05）；饲料2#组血清中血蓝蛋白（Hc）含量、T-AOC和SOD活力显著高于其他组（P<0.05），但该组血清中POD活力和MDA含量最低。综上，育肥饲料中以豆油：菜籽油=1:1的混合植物油替代不同水平鱼油对中华绒螯蟹成体雄蟹性腺发育无显著影响，且适宜的替代水平对中华绒螯蟹成体雄蟹的脂质代谢、抗氧化及免疫性能均无负面影响，其适宜的替代水平为25%~50%。
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