Electro-Chemo-Mechanical Failure Mechanisms of Solid-State Electrolytes

Solid-state lithium-metal batteries (SSLMBs) are considered as the next-generation energy storage systems due to their high theoretical energy density and safety. However, the practical deployment of SSLMBs has been impeded by the failure of solid-state electrolytes (SSEs) which is indicated by the increased impedance, elevated polarization, and capacity degradation. The failure is commonly a result of lithium (Li) dendrite growth and propagation, inactive Li generation, unstable interface formation, void and pore formation, and crack infiltration. The failure processes can be divided into electric failure, (electro)chemical failure, and mechanical failure based on the different mechanisms. The systematical understanding of SSEs failure is crucial for the development of SSEs. Therefore, this review comprehensively summarizes the details of the three SSEs failure to provide new insights for future studies, shedding light on the design of SSLMBs with high energy density, safety, and cycling stability. Failure mechanisms: This review provides a comprehensive summary of the coupled electro-chemo-mechanical failure mechanisms of solid-state electrolytes. The electric failure results from the short circuits caused by growth and propagation of Li dendrites and the capacity loss because of inactive Li formation. The formation of kinetics/thermal unstable interphase accounts for the (electro)chemical failure. Cracks infiltration and voids/pores formation lead to mechanical failure

Mapping Observations of Peptide-like molecules around Sagittarius B2

Peptide-like molecule, which has a close connection with the origin of life, has been detected in universe. Mapping observations of HCONH$_2$ and CH$_3$CONH$_2$, two simplest peptide-like molecules, are performed towards Sagittarius B2 (Sgr B2) complex with the IRAM 30m telescope. Seven transitions of HCONH$_2$ and five transitions of CH$_3$CONH$_2$ are used in analysis. The spatial distribution of excitation temperature and column density of HCONH$_2$ in the molecular envelope of Sgr B2 are obtained by the rotation diagrams. Assuming the same excitation temperature as HCONH$_2$, the column densities of CH$_3$CONH$_2$ are also calculated. The results show that excitation temperature ranges from 6 K to 46 K in the molecular envelope of Sgr B2. The abundance ratio between HCONH$_2$ and CH$_3$CONH$_2$ are calculated to explore the relationship among them, as well as HNCO mentioned in our pervious research. The abundance ratio of CH$_3$CONH$_2$/HCONH$_2$ varies from 10% to 20%, while that of HCONH$_2$/HNCO ranges from 1.5% to 10%. CH$_3$CONH$_2$ is enhanced with respect to HCONH$_2$ in the northwest region of Sgr B2. One transition of H$^{13}$CONH$_2$ is detected toward 12 positions of Sgr B2, from which a $^{12}$C/$^{13}$C ratio of 28.7 is obtained. A time-dependent chemical model with a short duration of X-ray burst is used to explain the observed abundances of HCONH$_2$ and CH$_3$CONH$_2$, with the best fitting result at T$\rm_{dust}$ = 53-56 K. More chemical reactions are required to be included into the model since the modeled abundance is lower than the observed one at the observed T$\rm_{dust}$

Soil functions and ecosystem services research in the Chinese karst Critical Zone

Covering extensive parts of China, karst is a critically important landscape that has experienced rapid and intensive land use change and associated ecosystem degradation within only the last 50 years. In the natural state, key ecosystem services delivered by these landscapes include regulation of the hydrological cycle, nutrient cycling and supply, carbon storage in soils and biomass, biodiversity and food production. Intensification of agriculture since the late-20th century has led to a rapid deterioration in Critical Zone (CZ) state, evidenced by reduced crop production and rapid loss of soil. In many areas, an ecological ‘tipping point’ appears to have been passed as basement rock is exposed and ‘rocky desertification’ dominates. This paper reviews contemporary research of soil processes and ecosystems service delivery in Chinese karst ecosystems, with an emphasis on soil degradation and the potential for ecosystem recovery through sustainable management. It is clear that currently there is limited understanding of the geological, hydrological and ecological processes that control soil functions in these landscapes, which is critical for developing management strategies to optimise ecosystem service delivery. This knowledge gap presents a classic CZ scientific challenge because an integrated multi-disciplinary approach is essential to quantify the responses of soils in the Chinese karst CZ to extreme anthropogenic perturbation, to develop a mechanistic understanding of their resilience to environmental stressors, and thereby to inform strategies to recover and maintain sustainable soil function. © 2019 Elsevier B.V

Decrease in the production of beta-amyloid by berberine inhibition of the expression of beta-secretase in HEK293 cells

<p>Abstract</p> <p>Background</p> <p>Berberine (BER), the major alkaloidal component of <it>Rhizoma coptidis</it>, has multiple pharmacological effects including inhibition of acetylcholinesterase, reduction of cholesterol and glucose levels, anti-inflammatory, neuroprotective and neurotrophic effects. It has also been demonstrated that BER can reduce the production of beta-amyloid_40/42, which plays a critical and primary role in the pathogenesis of Alzheimer's disease. However, the mechanism by which it accomplishes this remains unclear.</p> <p>Results</p> <p>Here, we report that BER could not only significantly decrease the production of beta-amyloid_40/42and the expression of beta-secretase (BACE), but was also able to activate the extracellular signal-regulated kinase1/2 (ERK1/2) pathway in a dose- and time-dependent manner in HEK293 cells stably transfected with APP695 containing the Swedish mutation. We also find that U0126, an antagonist of the ERK1/2 pathway, could abolish (1) the activation activity of BER on the ERK1/2 pathway and (2) the inhibition activity of BER on the production of beta-amyloid_40/42and the expression of BACE.</p> <p>Conclusion</p> <p>Our data indicate that BER decreases the production of beta-amyloid_40/42by inhibiting the expression of BACE via activation of the ERK1/2 pathway.</p

Distributed SLAM Using Improved Particle Filter for Mobile Robot Localization

The distributed SLAM system has a similar estimation performance and requires only one-fifth of the computation time compared with centralized particle filter. However, particle impoverishment is inevitably because of the random particles prediction and resampling applied in generic particle filter, especially in SLAM problem that involves a large number of dimensions. In this paper, particle filter use in distributed SLAM was improved in two aspects. First, we improved the important function of the local filters in particle filter. The adaptive values were used to replace a set of constants in the computational process of importance function, which improved the robustness of the particle filter. Second, an information fusion method was proposed by mixing the innovation method and the number of effective particles method, which combined the advantages of these two methods. And this paper extends the previously known convergence results for particle filter to prove that improved particle filter converges to the optimal filter in mean square as the number of particles goes to infinity. The experiment results show that the proposed algorithm improved the virtue of the DPF-SLAM system in isolate faults and enabled the system to have a better tolerance and robustness

Distributed SLAMusing improved particle filter for mobile robot localization,” The Scientific

The distributed SLAM system has a similar estimation performance and requires only one-fifth of the computation time compared with centralized particle filter. However, particle impoverishment is inevitably because of the random particles prediction and resampling applied in generic particle filter, especially in SLAM problem that involves a large number of dimensions. In this paper, particle filter use in distributed SLAM was improved in two aspects. First, we improved the important function of the local filters in particle filter. The adaptive values were used to replace a set of constants in the computational process of importance function, which improved the robustness of the particle filter. Second, an information fusion method was proposed by mixing the innovation method and the number of effective particles method, which combined the advantages of these two methods. And this paper extends the previously known convergence results for particle filter to prove that improved particle filter converges to the optimal filter in mean square as the number of particles goes to infinity. The experiment results show that the proposed algorithm improved the virtue of the DPF-SLAM system in isolate faults and enabled the system to have a better tolerance and robustness

On the evolution of n-octane atomization characteristics using an air-assisted intermittent spray method

In this study, droplet size and velocity of an intermittent air-assisted n-octane spray were measured using a Phase Doppler Particle Analyzer, focusing on the effect of operating parameters on time-resolved droplet behavior and local gas flow characteristics. An electro-magnetically actuated air-assisted injector, which features internal gas liquid premixing upstream and releasing through an annular nozzle, was used to generate intermittent sprays. The sampling time equalization method is employed to examine the time-resolved spray microscopic characteristics with various injection control parameters and spatial sampling positions. The droplet diameter range is found to be generally independent of air injection duration and sampling time while droplet velocity is correlated with these two parameters. A large air injection duration tends to accelerate droplets in the late spray period and leads to an increasing normalized gas flow velocity. Estimation of local gas flow turbulence intensity indicates a prominent radial sampling position dependence due to the rapid attenuation of the gas flow velocity away from the spray axis. A noteworthy finding for this intermittent air-assisted spray is that at 30 mm from the nozzle outlet, the zero point of droplet-gas mean slip velocity shifts toward the nozzle with sampling time. The time bin size employed to divide the sampling time has been proved to exert no influence on the statistical results of transient spray microscopic characteristics

Effect of Alkali and Alkaline Earth Metallic Species on Biochar Reactivity and Syngas Compositions during Steam Gasification

Biochars were prepared from the pyrolysis of the wood, leaf, and bark components of mallee biomass in a fixed-bed reactor at 750 °C. The results show that the volatilization of inherent alkali and alkaline earth metallic (AAEM) species is 10−20% during the pyrolysis of raw wood, bark, and leaf samples. Acid treatment of the biochar samples was also carried out to prepare a set of acid-treated biochar samples. Although the majority of the inherent AAEM species were removed by acid-treatment, there are always some AAEM species that could not be removed for all biochars. Steam gasification experiments of both the raw and acid-treated biochar samples were carried out in a fixed-bed reactor at 750 °C and a steam concentration of 8.2 vol %. Data on the instantaneous syngas composition were obtained as a function of biochar conversion during steam gasification. Our data illustrated the importance of, in the study of steam gasification reaction mechanisms and kinetics of solid fuels such as biochars, optimizing the reaction conditions to minimize steam consumption so that the steam partial pressure in the reactor is kept reasonably constant during the whole course of gasification.The results indicate that Na, K, and Ca retained in the biochars are the key catalytic species, with the catalytic effect appearing to be in the order K > Na > Ca during the steam gasification reaction of these biochars. During steam gasification, almost all of the inherent AAEM species in biochar are retained in the reacting biochar, throughout the course of conversion. Steam gasification of both the raw and acid-treated biochars produces high-quality syngas products that contain little methane. Further analysis shows that during the course of biochar conversion, the primary gasification product is most likely CO, and overall the water-gas-shift reaction is primarily responsible for the CO2 formation. It is found that the inherent AAEM species, although catalyzing the biochar gasification significantly, appear to have insignificant catalytic effect on the water-gas-shift reaction under the current gasification conditions