Improved Genetic Programming Algorithm Applied to Symbolic Regression and Software Reliability Modeling

The present study aims at improving the ability of the canonical genetic programming algorithm to solve problems, and describes an improved genetic programming (IGP). The proposed method can be described as follows: the first inves-tigates initializing population, the second investigates reproduction operator, the third investigates crossover operator, and the fourth investigates mutation operation. The IGP is examined in two domains and the results suggest that the IGP is more effective and more efficient than the canonical one applied in different domains.

Review of Core-shell structure zeolite-based catalysts for NO_(x)emission control

Nitrogen oxides(NO_(x))from diesel engine exhaust,is one of the major sources of environmental pollution.Currently,selective catalytic reduction with ammonia(NH_(3)-SCR)is considered to be the most effective protocol for reducing NO_(x)emissions.Nowadays,zeolitebased NH_(3)-SCR catalysts have been industrialized and widespread used in this field.Nevertheless,with the increasingly stringent environmental regulations and implementation of the requirement of“zero emission”of diesel engine exhaust,it is extremely urgent to prepare catalysts with superior NH_(3)-SCR activity and exceptional resistance to poisons(SO2,alkali metals,hydrocarbons,etc.).Core-shell structure zeolite-based catalysts(CSCs)have shown great promise in NH_(3)-SCR of NO_(x)in recent years by virtue of its relatively higher low-temperature activity,broader operation temperature window and outstanding resistance to poisons.This review mainly focuses on the recent progress of CSCs for NH_(3)-SCR of NO_(x)with three extensively investigated SSZ-13,ZSM-5,Beta zeolites as cores.The reaction mechanisms of resistance to sulfur poisoning,alkali metal poisoning,hydrocarbon poisoning,and hydrothermal aging are summarized.Moreover,the important role of interfacial effect between core and shell in the reaction of NH_(3)-SCR was clarified.Finally,the future development and application outlook of CSCs are prospected.

Engineering the electronic and geometric structure of VO_(x)/BN@TiO_(2)heterostructure for efficient aerobic oxidative desulfurization

Particle size governs the electronic and geometric structure of metal nanoparticles(NPs),shaping their catalytic performances in heterogeneous catalysis.However,precisely controlling the size of active metal NPs and thereafter their catalytic activities remain an affordable challenge in ultra-deep oxidative desulfurization(ODS)field.Herein,a series of highly-efficient VO_(x)/boron nitride nanosheets(BNNS)@TiO_(2)heterostructures,therein,cetyltrimethylammonium bromide cationic surfactants serving as intercalation agent,BNNS and MXene as precursors,with various VO_(x)NP sizes were designed and controllably constructed by a facile intercalation confinement strategy.The properties and structures of the prepared catalysts were systematically characterized by different technical methods,and their catalytic activities were investigated for aerobic ODS of dibenzothiophene(DBT).The results show that the size of VO_(x)NPs and V^(5+)/V^(4+)play decisive roles in the catalytic aerobic ODS of VO_(x)/BNNS@TiO_(2)catalysts and that VO_(x)/BNNS@TiO_(2)-2 exhibits the highest ODS activity with 93.7%DBT conversion within 60 min under the reaction temperature of 130℃and oxygen flow rate of 200 mL·min-1,which is due to its optimal VO_(x)dispersion,excellent reducibility and abundant active species.Therefore,the finding here may contribute to the fundamental understanding of structure-activity in ultradeep ODS and inspire the advancement of highly-efficient catalyst.