The 2-step domination problem is to find a minimum vertex set D of a graph such that every vertex of the graph is either in D or at distance two from some vertex of D. In the present paper, by using a labeling method,...The 2-step domination problem is to find a minimum vertex set D of a graph such that every vertex of the graph is either in D or at distance two from some vertex of D. In the present paper, by using a labeling method, we provide an O（m） time algorithm to solve the 2-step domination problem on block graphs, a superclass of trees.展开更多
首先以Hummers法制备还原态氧化石墨烯(RGO),其次通过溶胶-凝胶法和水热法分别制备TiO_(2)和TiO_(2)/RGO复合材料,然后向硝酸银溶液滴加氨水沉淀出纳米Ag并掺杂到TiO_(2)上,再以聚乙烯吡咯烷酮(PVP)为分散剂,以RGO为基体材料,用一步水...首先以Hummers法制备还原态氧化石墨烯(RGO),其次通过溶胶-凝胶法和水热法分别制备TiO_(2)和TiO_(2)/RGO复合材料,然后向硝酸银溶液滴加氨水沉淀出纳米Ag并掺杂到TiO_(2)上,再以聚乙烯吡咯烷酮(PVP)为分散剂,以RGO为基体材料,用一步水热法合成Ag@TiO_(2)/RGO复合光催化剂。复合材料通过FT-IR、XRD、SEM、DRS和BET等进行结构、组成、形貌和孔径大小的表征。将Ag@TiO_(2)/RGO用来光催化降解罗丹明B(RhB)溶液,结果表明,0.020 g该催化剂对50 mL 5 mg/L的RhB溶液在pH值为5、室温条件下的降解效果最好;经6次循环利用后,降解率依然能达到80%。展开更多
基金Supported by the National Natural Science Foundation of China(Grant No.11271365)the Domestic Senior Visiting Scholar Program in Higher Occupation Colleges in Jiangsu Province(Grant No.2014FX075)
文摘The 2-step domination problem is to find a minimum vertex set D of a graph such that every vertex of the graph is either in D or at distance two from some vertex of D. In the present paper, by using a labeling method, we provide an O（m） time algorithm to solve the 2-step domination problem on block graphs, a superclass of trees.
文摘首先以Hummers法制备还原态氧化石墨烯(RGO),其次通过溶胶-凝胶法和水热法分别制备TiO_(2)和TiO_(2)/RGO复合材料,然后向硝酸银溶液滴加氨水沉淀出纳米Ag并掺杂到TiO_(2)上,再以聚乙烯吡咯烷酮(PVP)为分散剂,以RGO为基体材料,用一步水热法合成Ag@TiO_(2)/RGO复合光催化剂。复合材料通过FT-IR、XRD、SEM、DRS和BET等进行结构、组成、形貌和孔径大小的表征。将Ag@TiO_(2)/RGO用来光催化降解罗丹明B(RhB)溶液,结果表明,0.020 g该催化剂对50 mL 5 mg/L的RhB溶液在pH值为5、室温条件下的降解效果最好;经6次循环利用后,降解率依然能达到80%。
