Experimental Study on the Cyclic Ampacity and Its Factor of 10 kV XLPE Cable

The load varies periodically, but the peak current of power cable is controlled by its continuous ampacity in China, resulting in the highest conductor temperature is much lower than90℃, the permitted long-term working temperature of XLPE. If the cable load is controlled by its cyclic ampacity, the cable transmission capacity could be used sufficiently. To study the 10 kV XLPE cable cyclic ampacity and its factor, a three-core cable cyclic ampacity calculation software is developed and the cyclic ampacity experiments of direct buried cable are undertaken in this paper. Experiments and research shows that the software calculation is correct and the circuit numbers and daily load factor have an important impact on the cyclic ampacity factor. The cyclic ampacity factor of 0.7 daily load factor is 1.20, which means the peak current is the 1.2 times of continuous ampacity. If the continuous ampacity is instead by the cyclic ampacity to control the cable load, the transmission capacity of the cable can be improved greatly without additional investment.

A method for power suppliers’optimal cooperative bidding strategies considering network losses

The bidding strategies of power suppliers to maximize their interests is of great importance.The proposed bilevel optimization model with coalitions of power suppliers takes restraint factors into consideration,such as operating cost reduction,potential cooperation,other competitors’bidding behavior,and network constraints.The upper model describes the coalition relationship between suppliers,and the lower model represents the independent system operator’s optimization without network loss(WNL)or considering network loss(CNL).Then,a novel algorithm,the evolutionary game theory algorithm(EGA)based on a hybrid particle swarm optimization and improved firefly algorithm(HPSOIFA),is proposed to solve the bi-level optimization model.The bidding behavior of the power suppliers in equilibrium with a dynamic power market is encoded as one species,with the EGA automatically predicting a plausible adaptation process for the others.Individual behavior changes are employed by the HPSOIFA to enhance the ability of global exploration and local exploitation.A novel improved firefly algorithm(IFA)is combined with a chaotic sequence theory to escape from the local optimum.In addition,the Shapley value is applied to the profit distribution of power suppliers’cooperation.The simulation,adopting the standard IEEE-30 bus system,demonstrates the effectiveness of the proposed method for solving the bi-level optimization problem.

Graphitic carbon nitride-based photocatalysts in the applications of environmental catalysis

Semiconductor photocatalytic technology has shown great prospects in converting solar energy into chemical energy to mitigate energy crisis and solve environmental pollution problems.The key issue is the development of high-efficiency photocatalysts.Various strategies in the state-of-the-art advancements,such as heterostructure construction,heteroatom doping,metal/single atom loading,and defect engineering,have been presented for the graphitic carbon nitride(g-C3N4)-based nanocomposite catalysts to design their surface chemical environments and internal electronic structures to make them more suitable for different photocatalytic applications.In this review,nanoarchitecture design,synthesis methods,photochemical properties,potential photocatalytic applications,and related reaction mechanisms of the modified high-efficiency carbon nitride-based photocatalysts were briefly summarized.The superior photocatalytic performance was identified to be associated with the enhanced visible-light response,fast photoinduced electron-hole separation,efficient charge migration,and increased unsaturated active sites.Moreover,the further advance of the visible-light harvesting and solar-to-energy conversions are proposed.

An enhanced least squares residual RAIM algorithm based on optimal decentralized factor

The Least Squares Residual(LSR)algorithm is commonly used in the Receiver Autonomous Integrity Monitoring(RAIM).However,LSR algorithm presents high Missed Detection Risk(MDR)caused by a large-slope faulty satellite and high False Alert Risk(FAR)caused by a small-slope faulty satellite.In this paper,the LSR algorithm is improved to reduce the MDR for a large-slope faulty satellite and the FAR for a small-slope faulty satellite.Based on the analysis of the vertical critical slope,the optimal decentralized factor is defined and the optimal test statistic is conceived,which can minimize the FAR with the premise that the MDR does not exceed its allowable value of all three directions.To construct a new test statistic approximating to the optimal test statistic,the Optimal Decentralized Factor weighted LSR(ODF-LSR)algorithm is proposed.The new test statistic maintains the sum of pseudo-range residual squares,but the specific pseudo-range residual is weighted with a parameter related to the optimal decentralized factor.The new test statistic has the same decentralized parameter with the optimal test statistic when single faulty satellite exists,and the difference between the expectation of the new test statistic and the optimal test statistic is the minimum when no faulty satellite exists.The performance of the ODFLSR algorithm is demonstrated by simulation experiments.

Structural Dependence of Competitive Adsorption of Water and Methanol on TiO2 Surfaces

采用的 TiO 2 锐钛矿(001 )-(1 牤獥？

Reaction heat-driven CO2 desorption during CO oxidation on Au(997) at low temperatures

Adsorption and reaction of CO and CO_2 were studied on oxygen-covered Au(997) surfaces by means of temperature- programmed desorption/reaction spectroscopy. Oxygen atoms(O(a)) on Au(997) enhances the CO_2 adsorption and stabilizes the adsorbed CO_2(a), and the stabilization effect also depends on the CO_2(a) coverage and involved Au sites. CO_2(a) desorption is the rate-limiting step for the CO+O(a) reaction to produce CO_2 on Au(997) at 105 K and exhibits complex behaviors, including the desorption of CO_2(a) upon CO exposures at 105 K and the desorption of O(a)-stabilized CO_2(a) at elevated temperatures. The desorption of CO_2(a) from the surface upon CO exposures at 105 K to produce gaseous CO_2 depends on the surface reaction extent and involves the reaction heat-driven CO_2(a) desorption channel. CO+O(a) reaction proceeds more easily with weakly-bound oxygen adatoms at the(111) terraces than strongly-bound oxygen adatoms at the(111) steps. These results reveal complex rate-limiting CO_2(a) desorption behaviors during CO+O(a) reaction on Au surfaces at low temperatures which provide novel information on the fundamental understanding of Au catalysis.

Direct evidence for hydrated protons as the active species in artificial photocatalytic water reduction into hydrogen

Photocatalytic water reduction to hydrogen over oxide semiconductors is one of the most extensively investigated artificial photocatalytic reactions, but the nature of the active species has not yet been elucidated. Here, we successfully prepared Pt/rutile TiO_2(110) surfaces with hydrated proton species via co-adsorption of hydrogen and water and observed the photocatalytic reduction of hydrated protons to H_2 upon UV light illumination. These results provide experimental evidence to prove hydrated protons as the active species for photocatalytic water reduction to hydrogen and demonstrate the occurrence of photocatalytic reduction of hydrated protons to H_2 within the H-bonding network on the catalyst surface instead of directly on the catalyst surface. The Pt-TiO_2 interface is capable of dissociating water to form hydroxyl groups that facilitate the formation of H-bonding network on the catalyst surface to enhance the photocatalytic H_2 production. Our results greatly advance fundamental understanding of artificial photocatalytic water reduction.

Site-and surface species-dependent propylene oxidation with molecular oxygen on gold surface

Fundamental understandings of Au-catalyzed oxidation reactions with molecular oxygen are of great importance. Herein we report a successful preparation of molecularly-adsorbed O;species on a stepped Au（997） single crystal model surface via a near-ambient pressure and low-temperature oxygen exposure and their oxidation reactivity with propylene via temperature programmed desorption spectra and polarization-modulated reflection-absorption infrared spectra. 02 molecularly adsorbs at the（111）step sites of Au（997） surface while C;H6 adsorbs at both（111） step sites and（111） terrace sites.C;H;（a）adsorbed at the（111） step sites is more stable than at the（111） terrace sites and its oxidation reactions are dominant; meanwhile, O2（a） is much more reactive than O（a） and prefers combustion reaction of C;H;（a）. C;H;（a） adsorbed at the（111） step sites undergoes combustion reactions with O;（a） to produce CO;and CO at low temperatures and partial oxidation reactions with O（a） to produce acrolein at high temperatures while C;H;（a） adsorbed at the（111） terrace sites undergoes combustion and partial oxidation reactions with O;（a） to respectively produce CO;/CO and acrolein at low temperatures. These results reveal site-and surface species-dependent reaction behaviors of propylene oxidation with molecular O;on Au surfaces and provide a complete fundamental understanding of oxidation reactions with molecular O;on Au surface.