Anatase/rutile-TiO2 hollow hierarchical architecture modified by SnO2 toward efficient lithium storage

Hierarchical architecture of anatase/rutile-mixed phases TiO₂ with hollow interior was successfully fabricated via a Topotactic synthetic method, including the synthesis of CaTiO₃ precursors and transforming them into TiO₂ through ion-exchange process. The as-synthesized TiO₂ hierarchical architectures as the anode materials were used as lithium-ion batteries (LIBs). Compared with TiO₂ samples, the TiO₂@SnO₂-5% shows the improved lithium storage capacity, cycling performance and rate properties. The impedance of the TiO₂ electrode decreases evidently after adding few amount of SnO₂. The hollow hierarchical structure with different compositions provide much more active sites, and well connect interface among anatase, rutile, and SnO₂, facilitating the electron and ion transport quickly and efficiently. Addition appropriate number of SnO₂ not only well kept the hierarchical architecture but also enhanced the capacity and conductivity of the TiO₂ sample. As a result, TiO₂@SnO₂-5% exhibited excellent lithium storage performance.     

Syngas Methanation over Spray‐Granulated Ni/Al2O3 Catalyst in a Laboratory Transport‐Bed Reactor

Syngas methanation in a laboratory transport‐bed reactor has been performed. It was found that the CO conversion over the granular Ni/Al₂O₃ catalyst only slightly increased with the rise of aeration gas velocity for the recycling valve but severely decreased due to decreased gas residence time in the reactor. The effect of increasing the temperature of the recycled catalyst on the CO conversion at atmospheric pressure was also studied. Both the experimental temperature rise along the transport‐bed reactor and the estimated heat balance involving reactions verified the high heat‐transfer efficiency and its technical superiority for syngas methanation.     

Potential of plasmonic microreactor for Photothermal hydrogen-enriched fuel production from biomethane

In the present article, a series of coupled computational physics - fluid dynamics models were developed aiming at assessing the feasibility of photothermal synthetic fuel production from biogas (biomethane) and steam blends using plasmonic nanostructure Ag/TiO₂ substrate (each, 0.1 μm in thickness) inside a thermal, momentum and mass transport boundary layer in a microreactor. A chain of partial and complete biogas reforming and water-gas shift reactions were modelled as the dominant chemical reactions responsible for synthetic fuel production from biomethane. Using equilibrium analysis, plausible thermodynamic operating conditions were identified and applied to the computational models. The effect of light wavelength (λ) on the reaction rate, chemical conversion extent, syngas quality, exergy partitioned in synthetic fuel, and composition of gas products were investigated. The results showed that the performance of the microreactor is wavelength-dependent. It was found that the highest production rate for the synthetic fuel was achieved at 580 nm < λ < 620 nm. Within the same wavelength range, the chemical conversion of biomethane to synthetic fuel reached 85% at steam to methane ratio of 3 and the synthetic fuel quality was >2.05, which is suitable for a Fischer-Tropsch process. It was also identified that the syngas quality of the synthetic fuel can be regulated by adjusting the wavelength of the light. The exposure time was also identified to be a critical parameter affecting the performance of the microreactor. For an exposure duration of up to 10 ns, high quality of synthetic fuel >2.05 can be achieved within the optimum wavelength range of 580 nm < λ < 620 nm.     

面向不均衡数据集的过抽样算法

合成少数类过抽样技术（SMOTE）中的噪声样本可能参与合成新样本，所以难以保证新样本的合理性。针对这个问题，结合聚类算法提出了改进算法CSMOTE。该算法抛弃了SMOTE在最近邻间线性插值的思想，使用少数类的簇心与其对应簇中的样本进行线性插值合成新样本，并且对参与合成的样本进行了筛选，降低了噪声样本参与合成的可能。在六个实际数据集上，将CSMOTE算法与四个SMOTE的改进算法以及两种欠抽样算法进行了多次的对比实验，CSMOTE算法在所有数据集上均获得了最高的AUC值。实验结果表明，CSMOTE算法具有更高的分类性能，可以有效解决数据集中样本分布不均衡的问题。     

Generating synthetic benchmark circuits for accelerated life testing of field programmable gate arrays using genetic algorithm and particle swarm optimization

Accelerated life testing (ALT) of a field programmable gate array (FPGA) requires it to be configured with a circuit that satisfies multiple criteria. Hand-crafting such a circuit is a herculean task as many components of the criteria are orthogonal to each other demanding a complex multivariate optimization. This paper presents an evolutionary algorithm aided by particle swarm optimization methodology to generate synthetic benchmark circuits (SBC) that can be used for ALT of FPGAs. The proposed algorithm was used to generate a SBC for ALT of a commercial FPGA. The generated SBC when compared with a hand-crafted one, demonstrated to be more suitable for ALT, measured in terms of meeting the multiple criteria. The SBC generated by the proposed technique utilizes 8.37% more resources; operates at a maximum frequency which is 40% higher; and has 7.75% higher switching activity than the hand-crafted one reported in the literature. The hand-crafted circuit is very specific to the particular device of that family of FPGAs, whereas the proposed algorithm is device-independent. In addition, it took several man months to hand-craft the SBC, whereas the proposed algorithm took less than half-a-day.     

Combined Decarbonization of Electrical Energy Generation and Production of Synthetic Fuels by Renewable Energies and Fossil Fuels

Power generation from renewable energy sources and fossil fuels are integrated into one system. A combination of technologies in the form of a carbon capture utilization (CCU)-combined power station is proposed. The technology is based on energy generation from fossil fuels by a coal power plant with CO₂ recovery from exhaust gases, and pyrolysis of natural gas to hydrogen and carbon, completed by reverse water-gas shift for the conversion of CO₂ to CO, which will react with hydrogen in a Fischer-Tropsch synthesis for synthetic diesel. The carbon from the pyrolysis can replace other fossil carbon or can be sequestered. This technology offers significant CO₂ savings compared to the current state of technology and makes an environmentally friendly use of fossil fuels for electricity and fuel sectors possible.     

Effect of biopolymers on permeability of sand-bentonite mixtures

Application of biopolymer-modified geomaterials in waste disposal practices is gaining wide acceptance due to their superior tensile characteristics and improved crack resistance. Permeability is an important design parameter which determines the suitability of a material as a liner for construction of engineered landfills. Given this, the permeability characteristics of sand-bentonite mixtures amended with biopolymers was studied using a modified-falling head permeability apparatus under an accelerated gravity environment. Both distilled water and synthetic leachate were utilized as permeant liquid to assess the role of biopolymer amendment on the permeation behavior of sand-bentonite mixtures. Experimental results indicate that addition of biopolymers causes aggregation of the clay platelets, which in turn enhances the permeation behavior of the biopolymer-modified sand-bentonite mixtures. These mixtures meet the regulatory requirement of the liner.     

Thermodynamic analysis and techno-economic assessment of synthetic natural gas production via ash agglomerating fluidized bed gasification using coal as fuel

Implementing coal to synthetic natural gas (SNG) is a key way to deal with the conflict between supply and demand of natural gas in China. For the coal to SNG process, gasification is a crucial unit, which determines the syngas composition and influences cost of coal to SNG system. In this current study, a coal to SNG system using ash agglomerating fluidized bed gasification is designed and modeled. According to the above results, the thermal performance and technoeconomic assessment of the coal to SNG system are performed. The research demonstrates that exergy efficiency and energy efficiency of the whole system are 55.37% and 61.50%, respectively. Additionally, the results of the economic evaluation show that the SNG production cost is 1.87 CNY/Nm³ with a coal price of 250 CNY/t and an electricity price of 0.65 CNY/kWh. Sensitivities to variables such as water price, electricity price, total equipment cost and coal price are performed. Coal price represents the most important sensitivity, but the sensitivity to water price is relatively small.     

Transient performances of the gas turbine recuperating waste heat through hydrogen rich fuels

Operational rules and control strategies of the chemically recuperated gas turbine (CRGT) in the marine propulsion are investigated in this paper. The Minimization of Gibbs free energy method is used to calculate the diesel-steam reforming reaction which products synthetic hydrogen rich fuels, and a universal model of the chemical regenerator which is easily applied to different application environments is created. The hydrogen production and hydrogen molar fraction are investigated to verify that the CRGT improve the combustion performances under low working conditions. Off-design calculations are performed to derive proper operational rules, and transient calculations are performed to investigate the best control strategies for the systems. The modelling approach of the chemical regenerator can be generally used in the chemically recuperated gas turbine. The elaborate operational rules can greatly improve the thermal efficiencies under every working condition. The system using synchronous control strategies have better regulation speed and operation stability than that using asynchronous control strategies.     

廊坊市地籍信息系统的建立

介绍了廊坊市地籍信息系统的建立过程及系统的功能、组成、运行环境等，并就系统中地籍模型的建立、查询统计功能的实现等问题进行了讨论。