Rolling Decision Model of Thermal Power Retrofit and Generation Expansion Planning Considering Carbon Emissions and Power Balance Risk

With the increasing urgency of the carbon emission reduction task,the generation expansion planning process needs to add carbon emission risk constraints,in addition to considering the level of power adequacy.However,methods for quantifying and assessing carbon emissions and operational risks are lacking.It results in excessive carbon emissions and frequent load-shedding on some days,although meeting annual carbon emission reduction targets.First,in response to the above problems,carbon emission and power balance risk assessment indicators and assessment methods,were proposed to quantify electricity abundance and carbon emission risk level of power planning scenarios,considering power supply regulation and renewable energy fluctuation characteristics.Secondly,building on traditional two-tier models for low-carbon power planning,including investment decisions and operational simulations,considering carbon emissions and power balance risks in lower-tier operational simulations,a two-tier rolling model for thermal power retrofit and generation expansion planning was established.The model includes an investment tier and operation assessment tier and makes year-by-year decisions on the number of thermal power units to be retrofitted and the type and capacity of units to be commissioned.Finally,the rationality and validity of the model were verified through an example analysis,a small-scale power supply system in a certain region is taken as an example.The model can significantly reduce the number of days of carbon emissions risk and ensure that the power balance risk is within the safe limit.

Effect of the Wick Deflection Angles on Heat Transfer Characteristics for the Flat LHP

Loop Heat Pipe(LHP)is an efficient two-phase heat transfer device,which can be used in waste heat recovery,electronics cooling,aerospace and other fields.The wick,the core component of LHP,plays an important role in its start-up and operation.In this paper,the wick fabricated by 3D printing technology had uniform and interconnected pores.In the experiment,the position of the parallel vapor removal grooves was always fixed towards the vapor outlet.When the cylindrical wick was placed in the evaporator,the rotation angle relative to its central axis could be changed,thus changing the number and shape of the pores facing the vapor removal grooves.The wick deflection angle represented its change in spatial position relative to the fixed vapor removal grooves.The effect of the wick deflection angles on the heat transfer characteristics of the flat LHP was experimentally investigated.It was found that with the change of deflection angle,the number of pores in the evaporation-oriented zone would also change,which had a significant impact on the start-up process and heat transfer performance of LHP.When the deflection angle was 30°,LHP could start fastest at a low heat load of 20 W and operate stable at a high heat load of 180 W.

An AGAMOUS-like factor is associated with the origin of two domesticated varieties in Cymbidium sinense (Orchidaceae)

Cymbidium has been artificially domesticated for centuries in Asia,which produced numerous cultivated varieties.Flowers with stamenoid tepals or those with multiple tepals have been found in different species of Cymbidium;however,the molecular basis controlling the formation of these phenotypes is still largely unknown.Previous work demonstrated that AGAMOUS/AG lineage MADS genes function in floral meristem determinacy as well as in reproductive organs development in both dicots and monocots,indicating a possible relationship with the origin of two flower varieties in Cymbidium.Here,we characterized and analyzed two AG lineage paralogues,CsAG1 and CsAG2,from Cymbidium sinense,both of which were highly expressed in the gynostemium column of a standard C.sinense.Interestingly,we detected ectopic expression of CsAG1 rather than CsAG2 in all floral organs of a stamenoid-tepal variety and significant down-regulation of CsAG1 in a variety with multiple tepals.Over-expression of CsAG1 in wild type Arabidopsis resulted in petal-to-stamen homeotic conversion,suggesting a conserved C-function of CsAG1 in the development of Cymbidium flower.Altogether,our results supported a hypothesis that disruption of a single AG-like factor would be associated with the formation of two domesticated varieties in C.sinense.

Microstructure and ferromagnetism of heavily Mn doped SiGe thin flims

Heavily Mn-doped SiGe thin films were grown by radio frequency magnetron sputtering and then treated by postgrowth thermal annealing.Structural characterizations reveal the coexistence of Mn-diluted SiGe crystals and Mn-rich nanoclusters in the annealed films.Magnetic measurements indicate the ferromagnetic ordering of the annealed samples above room temperature.The data suggest that the ferromagnetism is probably mainly contributed by the Ge-rich nanoclusters and partially contributed by the tensile-strained Mn-diluted SiGe crystals.The results may be useful for room temperature spintronic applications based on group IV semiconductors.

Synthesis and thermoelectric properties of Bi-doped SnSe thin films

Bi doped n-type SnSe thin films were prepared by chemical vapor deposition(CVD)and their structure and thermoelectric properties were studied.The x-ray diffraction patterns,x-ray photoelectron spectroscopy,and microscopic images show that the prepared SnSe thin films were composed of pure SnSe crystals.The Seebeck coefficients of the Bi-doped SnSe were greatly improved compared to that of undoped SnSe thin films.Specifically,Sn_(0.99)Bi_(0.01)Se thin film exhibited a Seebeck coefficient of905.8μV·K^(-1) at 600 K,much higher than 285.5μV·K^(-1) of undoped SnSe thin film.Further first-principles calculations reveal that the enhancement of the thermoelectric properties can be explained mainly by the Fermi level lifting and the carrier pockets increasing near the Fermi level due to Bi doping in the SnSe samples.Our results suggest the potentials of the Bi-doped SnSe thin films in thermoelectric applications.

Catalytic combustion of methane over a highly active and stable Ni0/Ce02 catalyst

In the last decades,many reports dealing with technology for the catalytic combustion of methane(CH4)have been published.Recently,attention has increasingly focused on the synthesis and catalytic activity of nickel oxides.In this paper,a NiO/CeO2 catalyst with high catalytic performance in methane combustion was synthe-sized via a facile impregnation method,and its catalytic activity,stability,and water-resistance during CH4 com-bustion were investigated.X-ray diffraction,low-tempera-ture N2 adsorption,thermogravimetric analysis,Fourier transform infrared spectroscopy,hydrogen temperature programmed reduction,methane temperature programmed surface reaction,Raman spectroscopy,electron paramag-netic resonance,and transmission electron microscope characterization of the catalyst were conducted to determine the origin of its high catalytic activity and stability in detail.The incorporation of NiO was found to enhance the concentration of oxygen vacancies,as well as the activity and amount of surface oxygen.As a result,the mobility of bulk oxygen in CeO2 was increased.The presence of CeO2 prevented the aggregation of NiO,enhanced reduction by NiO,and provided more oxygen species for the combustion ofCH4.The results of a kinetics study indicated that the reaction order was about 1.07 for CH4 and about 0.10 for O2 over the NiO/CeO2 catalyst.