To meet the demand for air-breathing power for wide-range vehicles at Mach 0–10,two thermal cycles with ammonia as the fuel and coolant were analyzed,namely the precooled rocket-turbine cycle(PC-RT)and the precooled ...To meet the demand for air-breathing power for wide-range vehicles at Mach 0–10,two thermal cycles with ammonia as the fuel and coolant were analyzed,namely the precooled rocket-turbine cycle(PC-RT)and the precooled gas-turbine cycle.Firstly,the operating modes of the precooled cycle engines were divided into turbine mode,precooling mode,and ramjet mode.Secondly,a fluid-structure coupling heat transfer program was used to evaluate the cooling effects of different fuels on the incoming high-temperature air.The result shows that the equivalent heat sink of ammonia is higher than that of other fuels and can meet the cooling requirement of at least Mach 4 in the precooling mode.Thirdly,the performance of the PC-RT in the turbine and precooling modes was compared at Mach 2.5.The result shows that air precooling alleviates the restriction of the pumping pressure on the minimum requiredβand improves the specific thrust within a reasonable range ofβ.Fourthly,the performance of the precooled cycle engines was compared when using different fuels.The result shows that the specific thrust of ammonia is greater than that of other fuels,and the performance advantages of ammonia are the most obvious in the precooling mode due to its highest equivalent heat sink.To sum up,the precooled cycle engines with ammonia as the fuel and coolant presented in this study have the advantages of no carbon emissions,low cost,high specific thrust,and no clogging of the cooling channels by cracking products.They are suitable for applications such as the first-stage power of the two-stage vehicle,and high Mach numbers air-breathing flight.展开更多
目的探讨薏苡仁油对人前列腺癌PC-3细胞的抑制作用。方法建立人前列腺癌PC-3细胞裸鼠移植瘤模型,以2、6 m L/kg剂量的薏苡仁油连续ig给药26 d,绘制肿瘤生长曲线,实验结束后摘除肿瘤组织,称质量,计算抑瘤率,并采用紫外-可见分光光度法测...目的探讨薏苡仁油对人前列腺癌PC-3细胞的抑制作用。方法建立人前列腺癌PC-3细胞裸鼠移植瘤模型,以2、6 m L/kg剂量的薏苡仁油连续ig给药26 d,绘制肿瘤生长曲线,实验结束后摘除肿瘤组织,称质量,计算抑瘤率,并采用紫外-可见分光光度法测定肿瘤组织中脂肪酸合成酶(FAS)活性。体外培养人前列腺癌PC-3细胞,应用SYBR Green I实时荧光定量RT-PCR法测定各组FAS m RNA的相对表达量。结果薏苡仁油6 m L/kg组抑瘤率为43.9%,肿瘤组织中FAS活性与模型组比较下降44.7%(P<0.05)。薏苡仁油20μL/m L水平上的FAS m RNA表达明显下降(P<0.05)。结论薏苡仁油对人前列腺癌PC-3细胞的荷瘤裸鼠模型有明显的抑瘤作用,该作用可能与下调FAS m RNA的表达和降低FAS的活性有关。展开更多
Inter-reference of competitive reverse transcription polymerase chain reaction (RT-PCR)was constructed by intron method to detect the change of PC mRNA level in the pathway ofcarbohydrate metabolism. The experiment ba...Inter-reference of competitive reverse transcription polymerase chain reaction (RT-PCR)was constructed by intron method to detect the change of PC mRNA level in the pathway ofcarbohydrate metabolism. The experiment based on the principle that 81bp intron sequencewas deleted in PC mRNA compared with PC DNA sequence. The 466bp competitive DNA templaterecombinant plasmid of PC mRNA was successfully built by a pair of primer and was clonedonce, PC DNA and PC mRNA could be inter-referred each other. The intron approach used inthe experiment has broken through the traditional method of constructing competitivetemplate.展开更多
基金This work was supported by the High-level Innovative Research Institute from the Department of Science and Technology of Guangdong Province(Grant No.2020B0909010003)the Ministry of Education of China(Grant No.8091B02052401).
文摘To meet the demand for air-breathing power for wide-range vehicles at Mach 0–10,two thermal cycles with ammonia as the fuel and coolant were analyzed,namely the precooled rocket-turbine cycle(PC-RT)and the precooled gas-turbine cycle.Firstly,the operating modes of the precooled cycle engines were divided into turbine mode,precooling mode,and ramjet mode.Secondly,a fluid-structure coupling heat transfer program was used to evaluate the cooling effects of different fuels on the incoming high-temperature air.The result shows that the equivalent heat sink of ammonia is higher than that of other fuels and can meet the cooling requirement of at least Mach 4 in the precooling mode.Thirdly,the performance of the PC-RT in the turbine and precooling modes was compared at Mach 2.5.The result shows that air precooling alleviates the restriction of the pumping pressure on the minimum requiredβand improves the specific thrust within a reasonable range ofβ.Fourthly,the performance of the precooled cycle engines was compared when using different fuels.The result shows that the specific thrust of ammonia is greater than that of other fuels,and the performance advantages of ammonia are the most obvious in the precooling mode due to its highest equivalent heat sink.To sum up,the precooled cycle engines with ammonia as the fuel and coolant presented in this study have the advantages of no carbon emissions,low cost,high specific thrust,and no clogging of the cooling channels by cracking products.They are suitable for applications such as the first-stage power of the two-stage vehicle,and high Mach numbers air-breathing flight.
文摘目的探讨薏苡仁油对人前列腺癌PC-3细胞的抑制作用。方法建立人前列腺癌PC-3细胞裸鼠移植瘤模型,以2、6 m L/kg剂量的薏苡仁油连续ig给药26 d,绘制肿瘤生长曲线,实验结束后摘除肿瘤组织,称质量,计算抑瘤率,并采用紫外-可见分光光度法测定肿瘤组织中脂肪酸合成酶(FAS)活性。体外培养人前列腺癌PC-3细胞,应用SYBR Green I实时荧光定量RT-PCR法测定各组FAS m RNA的相对表达量。结果薏苡仁油6 m L/kg组抑瘤率为43.9%,肿瘤组织中FAS活性与模型组比较下降44.7%(P<0.05)。薏苡仁油20μL/m L水平上的FAS m RNA表达明显下降(P<0.05)。结论薏苡仁油对人前列腺癌PC-3细胞的荷瘤裸鼠模型有明显的抑瘤作用,该作用可能与下调FAS m RNA的表达和降低FAS的活性有关。
基金supported by the National Natural Science Foundation of China(30230620).
文摘Inter-reference of competitive reverse transcription polymerase chain reaction (RT-PCR)was constructed by intron method to detect the change of PC mRNA level in the pathway ofcarbohydrate metabolism. The experiment based on the principle that 81bp intron sequencewas deleted in PC mRNA compared with PC DNA sequence. The 466bp competitive DNA templaterecombinant plasmid of PC mRNA was successfully built by a pair of primer and was clonedonce, PC DNA and PC mRNA could be inter-referred each other. The intron approach used inthe experiment has broken through the traditional method of constructing competitivetemplate.
