Conduction pathways of resource endowment affecting carbon intensity:Based on interprovincial data in China

By establishing a mathematical model and a basic analytical framework for the impact of resource endowments on carbon intensity,a traditional panel model without spatial panel effects was firstly constructed,a Durbin-Wu-Hausman test was conducted,and the model was set as a fixed-effects model based on the statistical values;secondly,the traditional panel model without spatial effects was estimated,and LM tests and robustness tests were conducted on the regression residuals.The LM test was then used to remove the fixed effect terms by the de-meaning method,and the Matlab 7.0 software was used to estimate the model.The stepwise introduction of variables was used to observe the effect of each variable on economic growth and to analyze the relationship between the magnitude and significance of the regression parameters of each variable.Finally,the path of conduction effect of resource endowment through mediating variable sinfluencing economic growth and carbon emissions,and thus carbon intensity,was constructed.The conclusion is that carbon intensity is inversely proportional to economic growth for a given level of carbon emissions.Therefore,if resource endowment promotes economic growth through mediating variables,it will lead to a decrease in carbon intensity,which is conducive to the achievement of emission reduction targets;conversely,if resource endowment hinders economic growth through mediating variables,it will lead to an increase in carbon intensity,which is not conducive to the achievement of emission reduction targets.

Localization and radiofrequency ablation of slow conducting pathway in left free wall

Objectives To study the Electrophysiologic characteristics and method of radiofrequency ablation in patients with slow conduction in left free wall. Methods When 5 cases induced tachycardia, using VS_2 program stimulation terminated the tachycardia to establish that ventricle is the part of reentry circle. Results No retrograde A waves in 4 cases but only 1 case present A wave in terminating tachycardia. The accessory pathways have decreasing conduction in One case. Successful ablation were located in ventricle sides. Conclusions Ventricular sense and S_2 program stimulation to terminate tachycardia is a reliable method to different atrial tachycardia . A wave of successful targets ahead of A wave of any coronary sinus leads is 8～22 ms.

Rational Design of High-Performance PEO/Ceramic Composite Solid Electrolytes for Lithium Metal Batteries

Composite solid electrolytes(CSEs)with poly(ethylene oxide)(PEO)have become fairly prevalent for fabricating high-performance solid-state lithium metal batteries due to their high Li~+solvating capability,flexible processability and low cost.However,unsatisfactory room-temperature ionic conductivity,weak interfacial compatibility and uncontrollable Li dendrite growth seriously hinder their progress.Enormous efforts have been devoted to combining PEO with ceramics either as fillers or major matrix with the rational design of two-phase architecture,spatial distribution and content,which is anticipated to hold the key to increasing ionic conductivity and resolving interfacial compatibility within CSEs and between CSEs/electrodes.Unfortunately,a comprehensive review exclusively discussing the design,preparation and application of PEO/ceramic-based CSEs is largely lacking,in spite of tremendous reviews dealing with a broad spectrum of polymers and ceramics.Consequently,this review targets recent advances in PEO/ceramicbased CSEs,starting with a brief introduction,followed by their ionic conduction mechanism,preparation methods,and then an emphasis on resolving ionic conductivity and interfacial compatibility.Afterward,their applications in solid-state lithium metal batteries with transition metal oxides and sulfur cathodes are summarized.Finally,a summary and outlook on existing challenges and future research directions are proposed.

Nuclear magnetic resonance studies of organic-inorganic composite solid electrolytes

Solid electrolytes have received widespread attention due to their higher safety than liquid electrolytes in the past decades.In particular,organic-inorganic composite solid electro-lytes(CSEs)in which inorganic fllers dispersed in polymer solid electrolytes are consid-ered to be one of the most promising candidate electrolytes for high-performance solid-state lithium batteries.Understanding the local environments and the conduction pathway/dynamics of Lit is essential for the design of high-performance CSEs.Nuclear magnetic resonance(NMR)is a non-invasive quantitative technique that has unique ca-pabilities in providing molecular structure information,morphological evolution,and measuring the movement of ions at different time scales.Therefore,for battery re-searchers,an accurate and comprehensive under standing of the basic principles and experimental design of solid-state NMR(SSNMR)is of great significance for investigating the abundant molecular structure and dynamics information in CSEs.The specific appli-cations of the SSNMR technique in CSEs are briefly introduced in this present review.

Screening possible solid electrolytes by calculating the conduction pathways using Bond Valence method

Inorganic solid electrolytes have distinguished advantages in terms of safety and stability, and are promising to substitute for conventional organic liquid electrolytes. However, low ionic conductivity of typical candidates is the key problem. As connective diffusion path is the prerequisite for high performance, we screen for possible solid electrolytes from the 2004 International Centre for Diffraction Data （ICDD） database by calculating conduction pathways using Bond Valence （BV） method. There are 109846 inorganic crystals in the 2004 ICDD database, and 5295 of them contain lithium. Except for those with toxic, radioactive, rare, or variable valence elements, 1380 materials are candidates for solid electrolytes. The rationality of the BV method is approved by comparing the existing solid electrolytes＇ conduction pathways we had calculated with those from ex- periments or first principle calculations. The implication for doping and substitution, two important ways to improve the conductivity, is also discussed. Among them LizCO3 is selected for a detailed comparison, and the pathway is reproduced well with that based on the density functional studies. To reveal the correlation between connectivity of pathways and conductivity, a/γ-LiAlO2 and Li2CO3 are investigated by the impedance spectrum as an example, and many experimental and theoretical studies are in process to indicate the relationship between property and structure. The BV method can calculate one material within a few minutes, providing an efficient way to lock onto targets from abundant data, and to investigate the struc- ture-property relationship systematically.

Reduced conductivity in sandwich-structured BFT@DA/PVDF flexible nanocomposites for high energy storage density in lower electric field

The Ba(Fe_(0.5)Ta_(0.5))O_(3)@DA/PVDF flexible composite films with sandwich-structured are prepared by solution-casting method.According to SEM image,the thickness of the composite film is about 15 mm and the each layer is about 5 mm.The sandwich-structured nanocomposite films not only have higher permittivity but also lower AC conductivity.The high permittivity is due to the large permittivity of BFT and the enhanced interface polarization between ceramic particles and polymer matrix.The low AC conductivity is due to the absence of conductive pathways in the PVDF layer.At low electric field strength of 150 MV/m,the energy density of sandwich-structure composite films filled with 1 vol% is 1.93 J/cm^(3).When the breakdown strength is 250 MV/m,the maximum energy storage density is increased to 4.87 J/cm^(3).The sandwich-structure Ba(Fe_(0.5)Ta_(0.5))O_(3)@DA/PVDF flexible composite films with outstanding energy storage properties in lower electric field can be used for wearable devices in the future.

Revisiting the ionic diffusion mechanism in Li_(3)PS_(4) via the joint usage of geometrical analysis and bond valence method

Inorganic solid electrolytes have obvious advantages on safety and electrochemical stability compared to organic liquid electrolytes,but the advance on high ionic conductivity of typical electrolytes is still undergoing.Although the first-principles calculation in the ion migration simulation is an important strategy to develop high-performance solid electrolyte,the process is very time-consuming.Here,we propose an effective method by combining the geometrical analysis and bond valance sum calculation to obtain an approximate minimum energy path preliminarily,in parallel to pave the way for the interoperability of low-precision and high-precision ion transport calculation.Taking a promising electrolyte Li_(3)PS_(4) as an example,we revisit its Li-ionic transport behavior.Our calculated Li-ion pathways and the activation energies(the corresponding values:1.09 eV vs.0.88 eV vs.0.86 eV)in γ-,β- and α-Li_(3)PS_(4) are consistent with the ones obtained from the first-principles calculations.The variations of the position of P-ions lead the rearrangement of the host PS_(4) tetrahedron,affecting the diffusion positions of Li-ions and further enabling high Li^(+) conductivity in β-Li_(3)PS_(4).