针对当前最优粒度选择算法对决策域动态变化带来的代价鲜有涉及的问题,引入可拓集方法,结合三支决策思想提出基于可拓域变化代价最小的最优粒度选择模型。首先由可拓评价法确定指标等级离散化数据表,以权重为粒子实施粒化,利用二元关系...针对当前最优粒度选择算法对决策域动态变化带来的代价鲜有涉及的问题,引入可拓集方法,结合三支决策思想提出基于可拓域变化代价最小的最优粒度选择模型。首先由可拓评价法确定指标等级离散化数据表,以权重为粒子实施粒化,利用二元关系交算子构建粒层空间;其次融合三支决策划分三个域,基于三个域的动态变化确定可拓集的五个域;然后研究可拓域变化的度量方式,构建代价矩阵,由可拓域变化代价最小确定最优粒层。该模型综合考虑静态和动态特征,为最优粒度选择提供新的途径。最后以黑龙江省水资源承载力数据为例,验证模型的有效性。利用分类与回归树(classification and regression trees, CART)进行灵敏度分析。结果表明模型具有较好的可推广性。展开更多
The corrosion behaviors of CNS-I and modified CNS-II were evaluated by exposing to superciritical water （SCW） at 550℃ and 25 MPa with a dissolved oxygen concentration of 200× 10 ^-9 for up to 1 000 h. Detailed...The corrosion behaviors of CNS-I and modified CNS-II were evaluated by exposing to superciritical water （SCW） at 550℃ and 25 MPa with a dissolved oxygen concentration of 200× 10 ^-9 for up to 1 000 h. Detailed corrosion results of these two alloys were provided, including the growth rate of the oxide scales, microstructure of the oxide scales, distribution of phases and alloying elements. The mass gains of CNS-I and modified CNS-II were 609.73 mg/dm2 and 459.42 mg/dm2 , respectively, after exposing to SCW for 1 000 h. A duplex oxide scale with an outer porous magnetite layer and an inner relatively dense magnetite/spinel-mixed layer was identified on CNS-I and modified CNS-II after the test. The oxide scales were rather porous at the beginning of the test but the porosity decreased with increase of the exposure duration. It was found that Fe was enriched in the outer oxide layer, Cr was enriched in the inner oxide layer and O existed at a very high concnetration in the whole oxide scale. Other alloying elements such as Mo, W, Mn were depleted from the outer oxide layer and showed slightly enrichment in the inner oxide layer. The distributution of Ni was different from other elements, it was enriched in the interface bewteen the base metal and the oxide scale and depleted in the outer and inner oxide layers.展开更多
文摘针对当前最优粒度选择算法对决策域动态变化带来的代价鲜有涉及的问题,引入可拓集方法,结合三支决策思想提出基于可拓域变化代价最小的最优粒度选择模型。首先由可拓评价法确定指标等级离散化数据表,以权重为粒子实施粒化,利用二元关系交算子构建粒层空间;其次融合三支决策划分三个域,基于三个域的动态变化确定可拓集的五个域;然后研究可拓域变化的度量方式,构建代价矩阵,由可拓域变化代价最小确定最优粒层。该模型综合考虑静态和动态特征,为最优粒度选择提供新的途径。最后以黑龙江省水资源承载力数据为例,验证模型的有效性。利用分类与回归树(classification and regression trees, CART)进行灵敏度分析。结果表明模型具有较好的可推广性。
基金Item Sponsored by National Basic Research Program of China(2007CB209800)
文摘The corrosion behaviors of CNS-I and modified CNS-II were evaluated by exposing to superciritical water （SCW） at 550℃ and 25 MPa with a dissolved oxygen concentration of 200× 10 ^-9 for up to 1 000 h. Detailed corrosion results of these two alloys were provided, including the growth rate of the oxide scales, microstructure of the oxide scales, distribution of phases and alloying elements. The mass gains of CNS-I and modified CNS-II were 609.73 mg/dm2 and 459.42 mg/dm2 , respectively, after exposing to SCW for 1 000 h. A duplex oxide scale with an outer porous magnetite layer and an inner relatively dense magnetite/spinel-mixed layer was identified on CNS-I and modified CNS-II after the test. The oxide scales were rather porous at the beginning of the test but the porosity decreased with increase of the exposure duration. It was found that Fe was enriched in the outer oxide layer, Cr was enriched in the inner oxide layer and O existed at a very high concnetration in the whole oxide scale. Other alloying elements such as Mo, W, Mn were depleted from the outer oxide layer and showed slightly enrichment in the inner oxide layer. The distributution of Ni was different from other elements, it was enriched in the interface bewteen the base metal and the oxide scale and depleted in the outer and inner oxide layers.
