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环氧形状记忆聚合物的热力学性能试验研究 被引量:3
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作者 王丽君 陈务军 +3 位作者 樊鹏玄 张大旭 房光强 曹争利 《哈尔滨工程大学学报》 EI CAS CSCD 北大核心 2018年第11期1804-1808,共5页
针对目前关于形状记忆聚合物热力学性能研究不足,本文对一种新研制的环氧形状记忆聚合物开展了三类热力学试验。首先进行了SMP拉伸、弯曲、扭转形变下的形状记忆自由回复试验,测定了形状记忆固定率与回复率,均可达到99. 4%以上;采用热... 针对目前关于形状记忆聚合物热力学性能研究不足,本文对一种新研制的环氧形状记忆聚合物开展了三类热力学试验。首先进行了SMP拉伸、弯曲、扭转形变下的形状记忆自由回复试验,测定了形状记忆固定率与回复率,均可达到99. 4%以上;采用热分析仪测定了材料-50℃~100℃的热膨胀应变随温度的关系,其值呈近似双线性,在玻璃转换点前后分别为4. 8×10^(-5)℃和2. 76×10^(-4)℃;最后进行了不同温度时的拉伸应力松弛试验及其不同加载速率拉伸试验,结果表明:在玻璃化转变温度附近,材料弹性模量与应力松弛现象发生明显的改变,形状记忆聚合物具有较强的时温相关非线性粘弹塑性力学行为特征。 展开更多
关键词 形状记忆聚合物 热膨胀系数 形状记忆自由回复 应力松弛 时温相关性 热力学性能
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Detecting the Relationship Between Summer Rainfall Anomalies in Eastern China and the SSTA in the Global Domain with a New Significance Test Method 被引量:4
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作者 LU Chuhan GUAN Zhaoyong WANG Panxing DUAN Mingken 《Journal of Ocean University of China》 SCIE CAS 2009年第1期15-22,共8页
It is suggested that the multiple samples in a correlation map or a set of correlation maps should be examined with significance tests as per the Bernoulli probability model. Therefore, both the contemporaneous and la... It is suggested that the multiple samples in a correlation map or a set of correlation maps should be examined with significance tests as per the Bernoulli probability model. Therefore, both the contemporaneous and lag correlations of summertime precipitation R in any one of the three regions of Northern China (NC), the Changjiang-Huaihe River Valley (CHRV), and Southern China (SC) with the SSTA in the global domain have been tested in the present article, using our significance test method and the method proposed by Livezey and Chen (1983) respectively. Our results demonstrate that the contemporaneous correlations of sum- mer R in CHRV with the SSTA are larger than those in NC. Significant correlations of SSTA with CHRV R are found to be in some warm SST regions in the tropics, whereas those of SSTA with NC R, which are opposite in sign as compared to the SSTA-CHRVR correlations, are found to be in some regions where the mean SSTs are low. In comparison with the patterns of the contemporaneous correlations, the 1 to 12 month lag correlations between NC R and SSTA, and those between CHRV summer R and SSTA show similar patterns, including the magnitudes and signs, and the spatial distributions of the coefficients. However, the summer rainfall in SC is not well correlated with the SSTA, no matter how long the lag interval is. The results derived from the observations have set up a relationship frame connecting the precipitation anomalies in NC, CHRV, and SC with the SSTA in the global domain, which is critically useful for our understanding and predicting the climate variabilities in different parts of China. Both NC and CHRV summer R are connected with E1 Nifio events, showing a ‘- -'pattern in an E1 Nifio year and a‘+ +' pattern in the subsequent year. Key words summer precipitation; eastern China; global sea surface 展开更多
关键词 temperature contemporaneous correlation time lag correlation significance test for multiple correlation maps
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Chill injury in the eggs of the migratory locust, Locusta migratoria (Orthoptera: Acrididae): the time-temperature relationship with high-temperature interruption 被引量:4
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作者 XIAO-HONGJING XIAN-HUIWANG LEKANG 《Insect Science》 SCIE CAS CSCD 2005年第3期171-178,共8页
Mortality of the overwintering egg of the migratory locust, Locustamigratoria L., was attributed to chill injury because of its occurrence well above the egg' ssupercooling point. In this study, two parameters, up... Mortality of the overwintering egg of the migratory locust, Locustamigratoria L., was attributed to chill injury because of its occurrence well above the egg' ssupercooling point. In this study, two parameters, upper limit of chill injury zone (ULCIZ) and sumof the injurious temperature (SIT), were used to examine the locust egg's cold hardiness. The valueof ULCIZ for the locust egg is 1.06 ± 0.54℃, and the SIT is -329.7 (hour ? degree). Thesuperoxide dismutase (SOD) and catalase (CAT) activities changed dramatically after cold stress,indicating that oxygen and hydroxide free radicals are probably efficiently detoxified at lowtemperatures. It was suggested that the nature of chill injury in locust egg might be a complex ofmetabolic disorder and a non-proportional decrease in enzymatic reaction and transports, because theLDH activity at low temperature increased significantly and the ATPase activity decreased withprolonged duration of exposure to low temperatures. The results from high temperature interruptionrevealed that the high temperature intervals significantly increased the survival of locust eggs. 展开更多
关键词 locusta migratoria chill injury antioxidant enzymes cold hardiness
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