Storage-reduction strategy for NO_(x) reduction from gas turbine exhaust with W-Ti-CeO_(x) catalyst in natural gas power plants

Traditional vanadium-based selective catalytic reduction(SCR)deNO_(x) catalyst can hardly adapt to the gas conditions(much high NO_(2)/NO_(x) ratio at lower temperature)of the start-up and low loading periods for a gas turbine.Therefore,a W-Ti-CeO_(x) catalyst with NO_(x) storage and reduction(NSR)function was developed in this work for gas turbine exhaust NO_(x) elimination.The experimental results reveal that W-Ti-CeO_(x) catalyst exhibits high NO_(2) adsorption capacity at relatively low temperature while that is quite low for V-W/TiO_(2).The abundant surface Ce^(3+) species can be mainly responsible for its high adsorption ability owing to the reaction between NO_(2) and Ce^(3+) to form nitrate/nitrite species and NO.Meanwhile,the adsorption capacity of W-Ti-CeO_(x) can easily regenerate at medium-high temperature and NH_(3)-SCR reaction.Furthermore,W-Ti-CeO_(x) also shows good NH_(3)-SCR activity,which can fulfill the deNO_(x) process at high temperature.The addition of W and Ti into ceria can enhance the surface acidity and redox ability,thereby increasing the SCR activity.This work proposes a novel storage-reduction strategy for NO_(x) elimination throughout the operation of gas turbines.

Multi-proxy evidence of environmental change related to collapse of the Liangzhu Culture in the Yangtze Delta,China

The Liangzhu Culture(5300–4300 cal.a BP)has been regarded as the culmination of the Neolithic Age in the Yangtze Delta and as an archaic state.However,the reason behind the collapse of the Liangzhu Culture remains controversial.Some scholars attributed it to social conflicts or foreign invasions,while others suggested that environmental deterioration,such as cold episodes,inundation and palaeo-typhoon events,disrupted the civilization.Notably,the yellowish silty sediments widely overlying the Liangzhu group sites have been presumed to be one of the vital clues to resolving these issues.The process and cause of their formation are key to understanding the decline in the Liangzhu Culture.In this study,two typical profiles composed of the Liangzhu cultural layer and yellowish silty sediments were collected in Liangzhu Ancient City.Multiple proxies,including pollen,phytoliths and diatoms,along with radiocarbon and optically stimulated luminescence dating and synthesized geochemical evidence from different sediments,were applied to reconstruct ecological and hydrological changes and discuss their linkage to cultural collapse.The regional ecology was typical freshwater wetlands during 4800–4400 cal.a BP,which facilitated rice farming and large-scale architectural engineering in Liangzhu Ancient City.Evidence from microfossils and dating of the yellowish silty sediments indicated that Liangzhu Ancient City was significantly affected by seawater after abandonment during 4300–3400 cal.a BP.Furthermore,geochemical evidence,including trace element and Sr-Nd isotopic compositions,suggested that the primary provenance of the yellowish silt was a mixture of sediments from the Qiantang River,East China Sea,Yangtze River and Yellow River,which had been transported to Liangzhu Ancient City by the Yellow Sea Coastal Current and a marine transgression.Therefore,based on evidence from archaeological sites and numerical simulation in the Yangtze Delta,it was supposed that the short-term accelerated relative sea-level rise at approximately 4400 cal.a BP caused a marine transgression around Taihu Lake,formed a large range of yellowish silty sediments,destroyed rice farming production,and ultimately led to the collapse of the Liangzhu Culture.

Reinforcement Learning-Based Handover Strategy for Space-Ground Integration Network with Large-scale Constellations

The space-ground integration network(SGIN)with large-scale constellations has become an important topic of the next generation mobile communication technology,in which the handover technology between the satellite and the ground is the key technology to ensure the continuity of user service.However,compared with the ground base station’s coverage of users,satellites have larger coverage and propagation delay,and large-scale constellations make multiple selectable service satellites above the same user.These phenomena bring great challenges to the handover algorithm.This paper designs a reinforcement learning-based multi-attribute satellite-ground handover strategy(RLMSGHS)for SGIN with large-scale constellations.Firstly,users are clustered with the attributes of location,speed,and bandwidth demand.Then,the handover decision can be made based on the proposed RLMSGHS according to the attributes of received signal strength(RSS),speed,network bandwidth utilization and,handover cost.Finally,the simulation results demonstrate that the heavy decision-making burden caused by the large-scale growth of users in the SGIN is significantly reduced.The multi-attribute handover decision in the SGIN is realized,which reduces the handover demand of users and improves the resource utilization rate of the SGIN.

Classification of archaic rice grains excavated at the Mojiaoshan site within the Liangzhu site complex reveals an Indica and Japonica chloroplast complex

To understand rice types that were utilized during postdomestication and in the modern age and the potential of genetic research in aged rice materials,archaeogenetic analysis was conducted for two populations of archaic rice grains from the Mojiaoshan site during the Liangzhu Period in China(2940 to 2840 BC).Sequencing after the PCR amplification of three regions of the chloroplast genome and one region of the nuclear genome showed recovery rates that were comparable to those in previous studies except for one chloroplast genome region,suggesting that the materials used in this work were appropriate for recovering genetic information related to domestication traits by using advanced technology.Classification after sequencing in these regions proved the existence of Japonica and Indica chloroplasts in archaic grains from the west trench,which were subsequently classified into eight plastid groups(type I–VIII),and indicated that these rice grains derived from different maternal lineages were stored together in storage houses at the Mojiaohsan site.Among these plastid groups,type V exhibited the same sequences as two modern Indica accessions that are utilized in basic studies and rice breeding.It was inferred that part of the chloroplast genome of archaic rice has been preserved in modern genetic resources in these two modern Indica accessions,and the results indicated that rice related to their maternal ancestor was present at the Mojiaoshan site during the Liangzhu Period in China.The usefulness of archaeogenetic analysis can be demonstrated by our research data as well as previous studies,providing encouragement for the possibility that archaeogenetic analysis can be applied to older rice materials that were utilized in the rice-domesticated period.