机器学习在材料服役性能预测中的应用

针对材料服役性能预测存在误差大、计算复杂、适用性差等问题,提出了基于数据挖掘的机器学习预测方法。首先阐述了机器学习的应用流程,并总结了常用模型原理及其在材料性能预测中的应用。然后采用多种机器学习模型对RPV钢的辐照性能进行预测,并通过Stacking集成方法提高了模型的预测精度。结果表明,机器学习可用于材料服役性能预测,具有较高的预测精度和可靠性。根据材料服役数据的不同特征选择合适的学习模型,同时进行模型融合和参数优化,可有效提高模型的预测精度及运算速度。     

Characterisation of projectiles composed of depleted uranium

Projectiles suspected to be composed of depleted uranium (DU) were found in Kosovo. Their properties were analysed using alpha and gamma ray spectrometry, mass spectrometry and electron microscopy. They were found to be composed of DU with small amounts of other elements such as Ti. 236U was detected in the penetrators, reflecting the use of reprocessed fuel. No transuranium elements were detected. The typical external dose rate meter is not the best option for mapping the location of penetrators from the ground. Monte Carlo calculations were performed in estimating possible skin doses. Penetrators in long-lasting contact with skin may cause a notable equivalent dose to skin.     

Possible role of organic matter in radiocaesium adsorption in soils

The aim of this review is to examine the hypothesis that organic matter decreases the adsorption of radiocaesium on clay minerals. The factors that determine radiocaesium mobility and bioavailability in soil are briefly outlined to show why a relationship between soil organic matter content and enhanced Cs bioavailability is paradoxical. In all the investigations reviewed the ionic compositions of both the solid and the solution phases have been strictly controlled. We show that the addition of organic matter to reference clay minerals causes decreases of up to an order of magnitude in the distribution coefficient of radiocaesium. Similarly, the chemical removal of organic matter from the clay-sized fraction of soil usually leads to an increase in Cs adsorption. We suggest that the nature of the organic matter and its interaction with mineral surfaces are as important as the amount present.     

政府不作为,百姓不用分类

睡意朦胧时,有媒体打电话来,问我对垃圾分类的看法.迷糊间毫不犹豫地蹦出一句话:"政府不作为,百姓完全可以不作垃圾分类."     

化工园区安全标准化管理体系的探讨

针对化工园区存在的安全风险,构建了包括9个一级要素和40个二级要素的安全管理标准化指标体系,设计了化工园区安全标准化管理考核评价标准,并对镇江某化工园区进行实证分析,得出该园区安全标准化等级为二级.依据考核结果,对该园区的安全管理提出了相应的对策措施.     

沙漠地带获得农业用水的一种方法——“卡丁”

前言在干旱地区,雨水稀少而且变化无常,任何地表水源,水量再小也是宝贵的。许多干旱环境中,地下水太深或含盐量很高,也不能利用。在印度的干旱地带—特别是在拉贾斯坦的加索麦地区(包括塔尔沙漠的一部分)—靠所谓“雨季”的雨水,不能满足大部分庄稼的需要。因雨季的雨水很不稳定,而且主要土壤多半是砂丘、薄砂砾层或岩石。因此,大规模     

Some comments on biological methylation ,global emissions and trade and on residence time in atmosphere of mercury

1　Ｆｏｒｍａｔｉｏｎａｎｄｂｒｅａｋ ｄｏｗｎｏｆｍｅｔｈｙｌｍｅｒｃｕｒｙｉｎｔｅｍｐｅｒａｔｅａｎｄｔｒｏｐｉｃａｌｅｃｏｓｙｓｔｅｍｓ　　Ｓｉｎｃｅｂｉｏｌｏｇｉｃａｌｍｅｔｈｙｌａｔｉｏｎｏｆｍｅｒｃｕｒｙｗａｓｆｉｒｓｔｄｅｓｃｒｉｂｅｄｉｎ 1967(Ｊｅｎｓｅｎ ,1969) ,ｓｅｖｅｒａｌｔｈｏｕｓａｎｄｐａｐｅｒｓｈａｖｅｂｅｅｎｐｕｂｌｉｓｈｅｄｏｎｔｈｅｓｕｂｊｅｃｔ.ＴｈｅｉｎｉｔｉａｌｓｔｕｄｉｅｓｗｅｒｅｄｏｎｅｉｎｆｒｅｓｈｗａｔｅｒｓｅｄｉｍｅｎｔｓｉｎＳｗｅｄｅｎｗｉｔｈｈｉ…     

光催化剂AgBr/Ag2MoO4@AgVO3的结构表征及其抗菌防污性能

目的制备新型的光催化复合材料,提高其光催化性能。方法通过水热法和原位生长法制备不同摩尔比的AgBr/Ag_2MoO_4@AgVO_3光催化剂。采用X射线衍射(XRD)、扫描电镜(SEM)和高分辨透射电子显微镜(HRTEM)等一系列手段对所制备的光催化剂进行表征,并以可见光为光源,有机污染物罗丹明B(RhB)为降解对象,进行光催化活性测试,考察不同复合量的光催化剂对反应活性的影响。同时,以铜绿假单胞菌细胞、金黄色葡萄球菌和大肠杆菌为模式菌,进行抗菌试验考察光催化剂的杀菌性能。结果该复合材料通过AgVO_3的(501)晶面、Ag_2MoO_4的(311)面和AgBr的(200)晶面紧密连接。在罗丹明B(RhB)溶液中加入该复合材料,120 min内降解率达到了94.9%,而纯AgVO_3的降解率为7.8%,说明复合后的材料光催化性能明显提高。此外,在光催化杀菌实验中,超过99.99%的大肠杆菌、金黄色葡萄球菌和铜绿假单胞菌细胞均在90 min内被杀死。结论复合后的AgBr/Ag_2MoO_4@AgVO_3异质结光催化剂具有优异的光催化降解性能、杀菌性能和稳定性,该催化剂对于环境污染的治理以及海洋杀菌防污处理都起到一定的作用。