A theoretical method for selecting strip rolling mill type that considered shape control ability was established using the figure alteration range that was worked by the alteration track of vector expressing strip'...A theoretical method for selecting strip rolling mill type that considered shape control ability was established using the figure alteration range that was worked by the alteration track of vector expressing strip's cross section (crown) to express the shape control ability of rolling mill. With the mathematical models and simulation software that were developed by the authors' own models, four types of mills were aimed, including HCM (6-high middle rolls shift type HC (high crown) -mill), HCMW (6-high middle rolls and work rolls shift type HC-mill), UCM (6-high middle rolls shift type HC-mill with middle roll bender) and UCMW (6-high middle rolls and work rolls shift type HC-mill with middle roll bender), and the shape and crown control ability of every mill type was analyzed and compared. An appropriate arrangement mode of tandem mill was brought forward. The results show that UCMW mill is a perfect choice for controlling shape and crown, and the area of control characteristics curve of UCMW (or UCM) is twice than that of HCM, but UCM mill is also a good choice for its simple frame. In other word, the shape and crown controlling ability of UCMW mill is better than that of UCM mill, but the frame of UCM mill is simpler than that of UCMW mill. As for the final type of mill, should be synthetically decided by thinking over fund and equipment technology.展开更多
目的提高F92耐热钢基体在600、630℃下的高温耐磨性能。方法采用超音速火焰喷涂方法(High velocity oxy-fuel,HVOF)在F92表面制备CoCrWSi、Stellite-6两种涂层,利用扫描电子显微镜(Scanning electron microscope,SEM)和X射线衍射仪(X-ra...目的提高F92耐热钢基体在600、630℃下的高温耐磨性能。方法采用超音速火焰喷涂方法(High velocity oxy-fuel,HVOF)在F92表面制备CoCrWSi、Stellite-6两种涂层,利用扫描电子显微镜(Scanning electron microscope,SEM)和X射线衍射仪(X-ray diffraction,XRD)分析涂层的表面、截面形貌和物相组成,通过显微维氏硬度计(HV-1000STA)、高温摩擦磨损试验机(UMT-TRIBOLAB)、二维轮廓仪(TencorD-100)测定其显微硬度、高温摩擦学性能和磨痕体积。结果采用超音速火焰喷涂技术制备的CoCrWSi、Stellite-6两种涂层表面较平整,与基体结合紧密,内部组织均匀无裂纹,涂层的厚度约为200μm。XRD分析表明,CoCrWSi、Stellite-6涂层在室温下的物相都由γ(Co)、Cr_(7)C_(3)、CrSi_(2)组成。硬度及耐磨性能测试显示,CoCrWSi、Stellite-6涂层的维氏硬度相较于F92基体分别提高了3.12、2.68倍,F92耐热钢在600、630℃时的平均摩擦因数分别为0.87、0.86,体积磨损率分别为0.49×10^(-4)、1.11×10^(-4)mm^(3)/(N·m),其磨损机理主要为疲劳磨损、黏着磨损、氧化磨损。相较于基体,CoCrWSi涂层在2种温度下的平均摩擦因数分别降低了68%、71%,约为0.28、0.25,体积磨损率分别降低了约95%、97%,为0.20×10^(-5)、0.30×10^(-5)mm^(3)/(N·m),这主要归功于内部的Cr2O3、γ(Co)、Co_(3)O_(4)相在高温摩擦过程中具有良好的润滑效果。Stellite-6涂层也能在一定程度上改善基体的高温耐磨性能,其平均摩擦因数为0.85、0.71,体积磨损率为0.32×10^(-4)、0.57×10^(-4)mm^(3)/(N·m)。2种涂层的主要磨损机理均为磨粒磨损和黏着磨损。结论采用超音速火焰喷涂制备的CoCrWSi、Stellite-6涂层可以改善F92耐热钢在600、630℃下的耐高温滑动磨损性能,且CoCrWSi涂层的防护效果更佳。展开更多
目的:探讨RNA m^(6)A甲基化修饰在脂肪细胞胰岛素抵抗中的作用及机制。方法:收集2型糖尿病患者术中赘余皮下脂肪组织,以非2型糖尿病患者同样组织为对照,检测组间RNA m^(6)A水平。高脂饮食诱导C57BL/6J小鼠构建胰岛素抵抗(in⁃sulin resis...目的:探讨RNA m^(6)A甲基化修饰在脂肪细胞胰岛素抵抗中的作用及机制。方法:收集2型糖尿病患者术中赘余皮下脂肪组织,以非2型糖尿病患者同样组织为对照,检测组间RNA m^(6)A水平。高脂饮食诱导C57BL/6J小鼠构建胰岛素抵抗(in⁃sulin resistance,IR)模型(HFD组,n=5,60%高脂饲料喂养16周),对照组10%低脂饲料喂养16周(CD组,n=5)。模型构建成功后,取附睾周围脂肪组织行表观转录组学m^(6)A甲基化修饰芯片检测,并借助MeRIP-qPCR实验、RT-qPCR以及RNA结合蛋白免疫沉淀测定(RNA Binding Protein Immunoprecipitation Assay,RIP)实验验证胰岛素信号转导相关基因变化;进一步观察METTL3小分子抑制剂STM2457对高脂饮食诱导下小鼠胰岛素信号转导基因的影响。结果:2型糖尿病患者和小鼠IR模型脂肪组织中总体m^(6)A修饰水平均升高(患者200 ng RNA t=-8.375,P<0.001;患者100 ng RNA t=-3.722,P=0.006;患者50 ng RNA t=-4.937;P=0.001;小鼠100 ng RNA t=-3.590,P=0.023;小鼠50 ng RNA t=-2.760,P=0.025)。表观转录组学检测证实IR的脂肪组织中1175个基因发生高m^(6)A修饰,55个基因发生低m^(6)A修饰,同时有182个基因呈现高m^(6)A修饰且低表达,包括AKT2、INSR、PIK3R1、ACACA、SREBF1等5个胰岛素信号转导关键基因,其中AKT2、INSR、ACACA、SREBF1等4个基因被确证并证实其与METTL3存在直接结合,其m^(6)A修饰水平受METTL3正向调控。STM2457作用下,胰岛素敏感性提高,且AKT2、INSR、ACACA、SREBF1转录水平上调,提示IR表型改善明显。结论:高脂饮食通过METTL3诱导脂肪细胞胰岛素信号转导基因AKT2、INSR、ACACA、SREBF1发生m^(6)A高甲基化修饰,诱导其低表达,阻滞胰岛素信号转导,进而参与诱发IR。展开更多
基金Project (50374058) supported by the National Natural Science Foundation of China and Shanghai Baosteel Group Co.
文摘A theoretical method for selecting strip rolling mill type that considered shape control ability was established using the figure alteration range that was worked by the alteration track of vector expressing strip's cross section (crown) to express the shape control ability of rolling mill. With the mathematical models and simulation software that were developed by the authors' own models, four types of mills were aimed, including HCM (6-high middle rolls shift type HC (high crown) -mill), HCMW (6-high middle rolls and work rolls shift type HC-mill), UCM (6-high middle rolls shift type HC-mill with middle roll bender) and UCMW (6-high middle rolls and work rolls shift type HC-mill with middle roll bender), and the shape and crown control ability of every mill type was analyzed and compared. An appropriate arrangement mode of tandem mill was brought forward. The results show that UCMW mill is a perfect choice for controlling shape and crown, and the area of control characteristics curve of UCMW (or UCM) is twice than that of HCM, but UCM mill is also a good choice for its simple frame. In other word, the shape and crown controlling ability of UCMW mill is better than that of UCM mill, but the frame of UCM mill is simpler than that of UCMW mill. As for the final type of mill, should be synthetically decided by thinking over fund and equipment technology.
文摘目的:探讨RNA m^(6)A甲基化修饰在脂肪细胞胰岛素抵抗中的作用及机制。方法:收集2型糖尿病患者术中赘余皮下脂肪组织,以非2型糖尿病患者同样组织为对照,检测组间RNA m^(6)A水平。高脂饮食诱导C57BL/6J小鼠构建胰岛素抵抗(in⁃sulin resistance,IR)模型(HFD组,n=5,60%高脂饲料喂养16周),对照组10%低脂饲料喂养16周(CD组,n=5)。模型构建成功后,取附睾周围脂肪组织行表观转录组学m^(6)A甲基化修饰芯片检测,并借助MeRIP-qPCR实验、RT-qPCR以及RNA结合蛋白免疫沉淀测定(RNA Binding Protein Immunoprecipitation Assay,RIP)实验验证胰岛素信号转导相关基因变化;进一步观察METTL3小分子抑制剂STM2457对高脂饮食诱导下小鼠胰岛素信号转导基因的影响。结果:2型糖尿病患者和小鼠IR模型脂肪组织中总体m^(6)A修饰水平均升高(患者200 ng RNA t=-8.375,P<0.001;患者100 ng RNA t=-3.722,P=0.006;患者50 ng RNA t=-4.937;P=0.001;小鼠100 ng RNA t=-3.590,P=0.023;小鼠50 ng RNA t=-2.760,P=0.025)。表观转录组学检测证实IR的脂肪组织中1175个基因发生高m^(6)A修饰,55个基因发生低m^(6)A修饰,同时有182个基因呈现高m^(6)A修饰且低表达,包括AKT2、INSR、PIK3R1、ACACA、SREBF1等5个胰岛素信号转导关键基因,其中AKT2、INSR、ACACA、SREBF1等4个基因被确证并证实其与METTL3存在直接结合,其m^(6)A修饰水平受METTL3正向调控。STM2457作用下,胰岛素敏感性提高,且AKT2、INSR、ACACA、SREBF1转录水平上调,提示IR表型改善明显。结论:高脂饮食通过METTL3诱导脂肪细胞胰岛素信号转导基因AKT2、INSR、ACACA、SREBF1发生m^(6)A高甲基化修饰,诱导其低表达,阻滞胰岛素信号转导,进而参与诱发IR。
