温度是影响火工品电磁防护其防护效果的主要因素,负温度系数(NTC)热敏电阻用于半导体桥(SCB)能有效提高其射频感度。采用恒流激励和电容放电两种实验,对不同环境温度下NTC热敏电阻对SCB性能的影响规律进行了研究。通过1 A 5 min恒流激...温度是影响火工品电磁防护其防护效果的主要因素,负温度系数(NTC)热敏电阻用于半导体桥(SCB)能有效提高其射频感度。采用恒流激励和电容放电两种实验,对不同环境温度下NTC热敏电阻对SCB性能的影响规律进行了研究。通过1 A 5 min恒流激励实验,分析了室温(25℃)和高温(70℃)时NTC热敏电阻的并联分流情况;25℃时NTC热敏电阻分走59%回路电流,70℃时,对小尺寸SCB(S-SCB)的分流率最大达到63%。在电容放电激励下,探讨了并联NTC热敏电阻SCB在25℃和70℃时电爆性能的变化情况。结果表明,并联NTC热敏电阻前后,典型尺寸(L-SCB)在25℃和70℃下的爆发时间和爆发消耗能量均无显著性变化。而S-SCB并联NTC热敏电阻后,当温度从25℃升至70℃,爆发时间从5.94μs增长到7.18μs,爆发消耗积分能量从0.388 m J降低到0.178 m J。展开更多
Carbon fiber oxidized by KMnO4 was combined with ethylene vinyl acetate（EVA） copolymer,the obtained composite shows a fine stability of thermal cycles and nearly unchanged switching temperature under thermal（cycles...Carbon fiber oxidized by KMnO4 was combined with ethylene vinyl acetate（EVA） copolymer,the obtained composite shows a fine stability of thermal cycles and nearly unchanged switching temperature under thermal（cycles）,at the same time negative temperature coefficient（NTC） phenomenon is eliminated.Solvent-extraction method is used to examine the interaction between EVA and CF and insolublity with the gel structure were found.The crosslinking network in the gel adsorb CF intensely which makes CF disperse in EVA uniformly,orientate consistently,combine with EVA tightly and shows the elimination of NTC phenomenon.The（switching） temperature of the composite in the heating process is not identical with that of the composite in the cooling process absolutely,but the temperatures in the above two processes are consistent with the outset of melting temperature and the end of crystallization temperature respectively.展开更多
文摘温度是影响火工品电磁防护其防护效果的主要因素,负温度系数(NTC)热敏电阻用于半导体桥(SCB)能有效提高其射频感度。采用恒流激励和电容放电两种实验,对不同环境温度下NTC热敏电阻对SCB性能的影响规律进行了研究。通过1 A 5 min恒流激励实验,分析了室温(25℃)和高温(70℃)时NTC热敏电阻的并联分流情况;25℃时NTC热敏电阻分走59%回路电流,70℃时,对小尺寸SCB(S-SCB)的分流率最大达到63%。在电容放电激励下,探讨了并联NTC热敏电阻SCB在25℃和70℃时电爆性能的变化情况。结果表明,并联NTC热敏电阻前后,典型尺寸(L-SCB)在25℃和70℃下的爆发时间和爆发消耗能量均无显著性变化。而S-SCB并联NTC热敏电阻后,当温度从25℃升至70℃,爆发时间从5.94μs增长到7.18μs,爆发消耗积分能量从0.388 m J降低到0.178 m J。
文摘Carbon fiber oxidized by KMnO4 was combined with ethylene vinyl acetate（EVA） copolymer,the obtained composite shows a fine stability of thermal cycles and nearly unchanged switching temperature under thermal（cycles）,at the same time negative temperature coefficient（NTC） phenomenon is eliminated.Solvent-extraction method is used to examine the interaction between EVA and CF and insolublity with the gel structure were found.The crosslinking network in the gel adsorb CF intensely which makes CF disperse in EVA uniformly,orientate consistently,combine with EVA tightly and shows the elimination of NTC phenomenon.The（switching） temperature of the composite in the heating process is not identical with that of the composite in the cooling process absolutely,but the temperatures in the above two processes are consistent with the outset of melting temperature and the end of crystallization temperature respectively.
