摘要：为了稳定农作物适宜生长的环境温度,该研究从微封装角度开发适用于农业应用的相变微胶囊储能材料,以农作物适宜生长温度(30℃左右)为基础制备TiO_(2)@正十八烷微胶囊(相变温度25~33℃),并通过氧化石墨烯(GO)对微胶囊的热性能进行修饰优化处理获得GO/TiO_(2)@正十八烷微胶囊。在此基础上,针对所制备的GO/TiO_(2)@正十八烷微胶囊测定了其样品的形貌、化学组成,最后对样品的热物性进行了检测分析。结果表明:所制备的微胶囊在扫描电镜观测下呈球形,平均直径1~3μm,颗粒均匀,且具有完整的核壳结构,还可观察到纳米GO片附着在微胶囊表面;红外测试结果表明GO与微胶囊并未发生化学反应,两者属于物理结合;试验所制备的储能微胶囊的包封率约为52.9%,利用质量分数为1%、2%、3%GO修饰后微胶囊包封率分别为43.3%、41.2%、37.6%,差示扫描量热仪测试数据表明TiO_(2)@正十八烷微胶囊的熔融焓和结晶焓分别为120、116 J/g;采用质量分数为1%、2%、3%的GO对所制备的TiO_(2)@正十八烷微胶囊进行修饰后,其热导率相比未经GO修饰微胶囊分别提升了57.5%、86.3%、104.2%。最后,综合差示扫描量热(Differential scanning calorimetry)测试和热重分析测试数据可知该研究方法所制备的GO/TiO_(2)@正十八烷微胶囊具有较为理想的相变潜热和高导热性能的特性,同时其具有良好的热稳定性和使用寿命,应用前景广泛,可为低温能源的二次利用提供一种参考方案。

摘要：Sudden earthquakes pose a threat to the running safety of trains on high-speed railway bridges,and the stiffness of piers is one of the factors affecting the dynamic response of train-track-bridge *** this paper,a experiment of a train running on a high-speed railway bridge is performed based on a dynamic experiment system,and the corresponding numerical model is *** reliability of the numerical model is verified by ***,the experiment and numerical data are analyzed to reveal the pier height effects on the running safety of trains on *** results show that when the pier height changes,the frequency of the bridge below the 30 m pier height changes greater;the increase of pier height causes the transverse fundamental frequency of the bridge close to that of the train,and the shaking angle and lateral displacement of the train are the largest for bridge with 50 m pier,which increases the risk of derailment;with the pier height increases from 8 m to 50 m,the derailment coefficient obtained by numerical simulations increases by 75% on average,and the spectral intensity obtained by experiments increases by 120% on average,two indicators exhibit logarithmic variation.

摘要：目的 探讨应用皮瓣、肌皮瓣修复放射性溃疡的临床效果。方法 术前应用彩色多普勒影像技术设计胸壁周围拟转移的轴型皮瓣，由放疗科会诊确定放疗区域，将溃疡连同周围放射性皮炎或纤维化区域完全切除后应用皮辩修复22例。包括背阔肌皮瓣8例，腹直肌皮辩9例，腹直肌皮瓣联合胸大肌皮瓣1例，侧胸皮瓣2例，胸脐皮瓣2例。皮瓣切取最大面积26cm×16cm。结果 1例因胸壁缺损导致移植皮瓣随呼吸浮动而出现背阔肌皮瓣坏死。1例静脉回流障碍致皮瓣远端部分坏死，经再次清创植皮愈合。其余20例均Ⅰ期愈合。随访3个月-9年，未见溃疡复发，皮瓣质地好。结论 术前应用彩色多普勒影像技术设计轴型皮瓣，术中扩大切除放射性溃疡后应用皮瓣、肌皮瓣修复创面。疗效满意，可有效预防溃疡的发生。