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991.
992.
目前国内很多"信号与系统"的教材中讨论了LTI连续时间系统零状态响应的一些求解方法,本文根据现有的信号与系统教材中连续时间系统零状态响应的求解方法,分别从利用冲激响应与激励的卷积、微分方程和变换域三方面求解零状态响应,并给出了实例说明了其正确性。 相似文献
993.
Immunomodulatory properties of the milk whey products obtained by enzymatic and microbial hydrolysis
Shang‐Min Huang Kun‐Nan Chen Yen‐Po Chen Wei‐Sheng Hong Ming‐Ju Chen 《International Journal of Food Science & Technology》2010,45(5):1061-1067
The objective of this study was to investigate the in vitro immunomodulatory effect of milk whey through enzymatic hydrolysis, microbial fermentation and two‐stage hydrolytic reactions (enzymatic and microbial reactions) by analysing cytokine profiles. Results indicated that the milk whey sample fermented by Lactobacillus kefiranofaciens M1 and two‐stage hydrolytic reactions (hydrolysed by Alcalase and then fermented by L. kefiranofaciens M1) could significantly induce the production of tumour necrosis factor (TNF)‐α and IL‐12 compared with the milk whey control and enzymatic treatments. Further characterisation of the immunomodulatory factor by membrane filtration and mutanolysin hydrolysation, the stimulatory activity for IL‐12 and TNF‐α production was found to be reduced and to be correlated positively with the cell wall components in L. kefiranofaciens M1. In addition, Th2‐polarised splenocytes revealed that L. kefiranofaciens M1 had both IL‐12 inducing and IL‐4 repressing activities. These results suggested that L. kefiranofaciens M1 could direct the Th1/Th2 balance toward Th1. 相似文献
994.
交联聚乙烯塑料电缆绝缘失效的实验研究 总被引:3,自引:2,他引:1
研究了不同高温和热老化作用对交联聚乙烯绝缘电缆(YJV)和阻燃交联聚乙烯绝缘电缆(ZR-YJV)绝缘失效的影响.使用401型老化试验箱和高温管式炉.预热后,在15 min内分别升温至400 ℃、450 ℃、500 ℃、550 ℃和600 ℃.结果:①对确定的绝缘材料,绝缘失效温度基本固定,设定温度升高,绝缘失效时间缩短,与环境温度和升温速率基本无关.②与YJV相比,ZR-YJV绝缘失效温度有所上升,但上升幅度较小.③热老化对电缆绝缘失效温度的影响显著,老化程度越大,失效温度下降越明显. 相似文献
995.
Abstract A relatively simple technique for the prediction of the thermal conductivity of polar organic fluids over the temperature range from 0° to 100°C is presented. The proposed model is basically derived via the generalized property correlation model developed by Riazi and Daubert in 1980. The method requires, as input, only normal boiling point, specific gravities and dipole moments or acentric factors for each compound of interest. Predicted thermal conductivities are compared with 93 literature data for 12 polar liquids. Average deviation between prediction and experiment is approximately within 8–12%, depending on the type of third input parameter, as opposed to 17% for the much involved method of Robins and Kingrea previously recommended. 相似文献
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Jaime C. Auton Mark W. Wiggins Ben J. Searle Thomas Loveday Nan Xu Rattanasone 《The Journal of communication》2013,63(3):600-616
The readback/hearback protocol is a radio procedure intended to reduce communication errors in technical industries. It consists of the delivery of an instruction to a receiver, and the readback of that instruction by the receiver to confirm to the sender that it has been heard accurately. It does not, however, ensure that the receiver has understood the instruction. Using 2 samples within electricity transmission control, the present research explored whether the prosodic cues that listeners use to interpret uncertainty are also used to judge whether a receiver is perceived to have understood an instruction. Rising intonation and filled interturn delays were identified as prosodic cues that operators use to identify nonunderstandings. Theoretical and practical implications of the findings are considered. 相似文献
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1000.
制革工业项目环评现状及对策探讨 总被引:2,自引:0,他引:2
重点阐述目前制革工业建设项目环境影响评价的基本现状,分析了存在问题及造成这些问题的主要原因,并在此基础上提出了相应的对策建议。 相似文献