Although alkaline zinc-manganese dioxide batteries have dominated the primary battery applications, it is challenging to make them rechargeable. Here we report a high-performance rechargeable ...zinc-manganese dioxide system with an aqueous mild-acidic zinc triflate electrolyte. We demonstrate that the tunnel structured manganese dioxide polymorphs undergo a phase transition to layered zinc-buserite on first discharging, thus allowing subsequent intercalation of zinc cations in the latter structure. Based on this electrode mechanism, we formulate an aqueous zinc/manganese triflate electrolyte that enables the formation of a protective porous manganese oxide layer. The cathode exhibits a high reversible capacity of 225 mAh g
and long-term cyclability with 94% capacity retention over 2000 cycles. Remarkably, the pouch zinc-manganese dioxide battery delivers a total energy density of 75.2 Wh kg
. As a result of the superior battery performance, the high safety of aqueous electrolyte, the facile cell assembly and the cost benefit of the source materials, this zinc-manganese dioxide system is believed to be promising for large-scale energy storage applications.The development of rechargeable aqueous zinc batteries are challenging but promising for energy storage applications. With a mild-acidic triflate electrolyte, here the authors show a high-performance Zn-MnO
battery in which the MnO
cathode undergoes Zn
(de)intercalation.
Objective To explore the anxiety status and coping strategies of clinical postgraduates, and to provide practical approaches to promote their mental health. Methods Using the phenomenological ...research method of qualitative research, 12 subjects were interviewed in a semi-structured way. Using the 7-step analysis method of Colaizzi phenomenology, the original data were analyzed and summarized. Results Five themes were extracted, including stress sources and psychological condition, interpersonal relationship, adjustment to cope with stress, self-understanding, career understanding and future vision. Clinical work, scientific research and economic pressures were the main causes of anxiety to the interviewees, who made cognitive, psychological, attitudes and behaviors adjustments, they hope to achieve a good work-life balance in the future. Conclusions Effective measures should be taken in view point of individual, school, family and social dimensions to alleviate anxiety and promote their physical and mental he
Water quenched blast furnace slag is an excellent hydrated material. However, dry granulation is a new treatment method for molten blast furnace slag that has numerous advantages compared to water ...quenching. This study investigated the size distribution of slag particles obtained from the dry granulation of molten slag. In addition, the effect of using the slag obtained from dry granulation in slag cement blends was analyzed. All the results showed that there was a wide size distribution range of blast furnace slag particles in ligament formation. The mean diameter of the solid particles decreased as the rotating speed increased. Meanwhile, the glass content in slag particles decreased for a fixed diameter of the metal collecting tray. The strength of slag cement concrete was low at a low rotating speed. In contrast, obtaining slag particles at a high rotating speed was beneficial for producing a compact structure in the slag cement blend.
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•The mean diameter of solid particles decreased with an increase in rotating speed.•It is easy to form compact structure in slag cement at high rotating speed.•The strength of slag cement was determined by slag powder size distribution.
The disintegration of liquid by rotary cups has been investigated experimentally. The mechanism of direct drop formation and ligament formation in a rotary cup was studied using photos taken by a ...high-speed camera. Two kinds of liquids and three kinds of cups were used in the experiment. In the study, we found that three different types of disintegration formation occur as the angular speed increases in a given flow rate. The equations have been derived theoretically for calculating diameter of liquid drop produced by direct drop formation and ligament formation and the dimensionless equations obtained from the experimental results are applicable for calculating diameter of drops in a wide range of operating conditions. In the process of disintegration by ligament formation, the diameter of liquid drop is determined by the diameter of tail end of ligament, which was constant in diameter. The transition equations from direct drop formation to ligament formation and ligament formation to sheet formation arranged by three dimensionless parameters and compared with various experimental results. The transition equations fit quite well in the trend shown by the experimental date and they are applicable in a particular range of We, i.e. 103<We<105.
► Mechanism of direct drop formation and ligament formation in a rotary cup was investigated. ► Equations have been derived theoretically for calculating diameter of liquid drop. ► Diameter of tail end of the ligament was constant in the process of disintegration by ligament formation. ► Transition equations fit well in the trend shown by experimental results.
Dry granulation is an attractive alternative to water quenching because of saving energy and reducing water consumption. In many dry granulation technologies, the high-temperature molten slag is ...atomized to slag particles, and the thermal energy from high-temperature slag particles is recovered by physical and chemical methods. In the present study, a technique for thermal energy recovery from high-temperature slag particles using a gravity bed waste heat boiler was exploited. The heat transfer characteristics of a laboratory-scale gravity bed waste heat boiler were investigated. An increase in Reynolds number (Re) showed no effect on the heat transfer coefficient or recovery efficiency. However, the heat transfer coefficient and recovery efficiency increased with a decrease in particle diameter and an increase in the velocity of descending particles. Compared with those observed with an aligned arrangement of the boiler tubes, the heat transfer coefficient and the recovery efficiency were higher in a staggered arrangement. The semi-empirical relations regarding the heat transfer coefficient between slag particles and boiler tubes were obtained based on experimental data and can be used to calculate the heat transfer coefficient within a certain range.
•Dry granulation for molten blast furnace slag is an attractive alternative to wet granulation.•The heat transfer characteristic of bench-scale gravity bed waste heat boiler is investigated.•The relations obtained can be used to calculate heat transfer coefficient within a certain range.
Prostate cancer (PCa) is the second frequent malignancy among men in the world. Exosomal circular RNAs (circRNAs) have been reported to function in PCa progression. The current study aimed to ...investigate the role of exosomal circRNA homeodomain-interacting protein kinase 3 (circHIPK3) in PCa development. Exosomes were extracted from serum and cells utilizing commercial kit, and identified by transmission electron microscopy (TEM), Western blot assay and nanoparticle tracking analyzer. Relative expression of circHIPK3, microRNA (miR)-212 and B-cell specific MMLV insertion site-1 (BMI-1) was examined by quantitative real-time PCR or Western blot assay. Receiver Operating Characteristic (ROC) analysis was conducted to assess the diagnostic potential of exosomal miR-212. Cell viability, and metastasis including migration and invasion, were detected by Methyl thiazolyl tetrazolium (MTT) assay and Transwell assay, respectively. Cell apoptosis was monitored using flow cytometry. The interaction between miR-212 and circHIPK3 or BMI-1 was validated by dual-luciferase reporter assay. Xenograft tumor assay was employed to explore the role of exosomal circHIPK3
in vivo
. Exosomal circHIPK3 was increased in serum of PCa patients, and could discriminate PCa patients from normal volunteers. Depletion of exosomal circHIPK3 or overexpression of exosomal miR-212 reduced viability, migration and invasion, but promoted cell apoptosis in PCa cells, which was attenuated by miR-212 inhibition or BMI-1, respectively. MiR-212 targeted BMI-1, and downregulated BMI-1 expression. Exosomal circHIPK3 knockdown also suppressed tumor growth
in vivo
. Exosomal circHIPK3 knockdown inhibited PCa progression by regulating miR-212/BMI-1 axis, at least in part, offering a new insight into the molecular mechanism of PCa.
The laminar flame speeds of CH4/O2/CO2 mixtures in atmospheric conditions (300 K and 1 atm) were studied using a Bunsen burner. The surface area methodology based on images of flame was performed to ...obtain the laminar flame speeds for a range of equivalence ratios (from 0.6 to 1.4, step 0.1), oxygen concentrations (from 25% to 35%). The experimental data were compared to numerical flame speed predictions which was based on GRI-Mech.ver 3.0 mechanism using a Chemkin package. The results showed that the maximum of flame speeds appeared at the stoichiometric ratio. With an increase in O2 concentration, the flame speeds increased. The effect of CO2 dilution was also investigated with experimental measurements, flame structure analysis and reaction pathway analysis from calculation. In premixed CH4/O2/CO2 flame, the combustion reactants, important intermediate and products concentration became lower and the flame thickness became thicker compared to CH4/O2/N2 mixtures. The major oxidation pathway of CH4/O2/CO2 remain unchanged but contribution rates of major intermediates formation have changed a lot. In addition, a part of secondary chemical pathways have changed.
•Measurements of laminar flame speeds of CH4/O2/CO2 mixtures with another approach.•The reaction pathway of CH4/O2/CO2 mixtures was investigated.•A modified flame speed empirical formula for CH4/O2/CO2 mixtures was given.
Rotary cup atomization for molten slag granulation is an attractive alternative to water quenching. However, the mechanism of disintegration of molten slag must be assessed. In the present study, a ...glycerol/water mixture was substituted for molten slag, and the mechanism of ligament formation in a rotary cup was investigated using photos taken by a high-speed camera. The effects of the angular speed and inner depth of the rotary cup on ligament disintegration was investigated.
The results showed that one state of disintegration may transform into another state as the angular speed of the rotary cup increases at a given liquid flow rate. During ligament formation, the number of ligaments increased with an increase in the angular speed of the rotary cup, and a decrease in the diameter of ligament and liquid drop was observed. Moreover, the initial point of disintegration of the ligament moved to the lip of the rotary cup as the angular speed increased. An equation describing the relationship between the diameter of the liquid drop and various factors was used to predict the diameter of the liquid drop. A rotary cup with an inner depth of 30mm was the best choice for granulation. The results of the present study will be useful for designing devices used in molten slag granulation.
►The results can be used in the granulation of molten blast furnace slag. ► The three different states of disintegration occur as the angular speed of rotary cup increases. ► The mechanism of ligament disintegration is analyzed. ► Eq. (8) can be used to predict the diameter of liquid drop. ► A rotary cup with an inner depth of 30mm is optimal for granulation.
Polycyclic aromatic hydrocarbons (PAHs) are widespread, persistent environmental pollutants. They exert toxic effects at different developmental stages of plants. Plant defense mechanisms against ...PAHs are poorly understood. To this end, transcriptomics and widely targeted metabolomic sequencing were used to study the changes in gene expression and metabolites that occur in the roots of Salix viminalis subjected to phenanthrene stress. Significant variations in genes and metabolites were observed between treatment groups and the control group. Thirteen amino acids and key genes involved in their biosynthesis were upregulated exposed to phenanthrene. Cysteine biosynthesis was upregulated. Sucrose, inositol galactoside, and mellidiose were the main carbohydrates that were largely accumulated. Glutathione biosynthesis was enhanced in order to scavenge reactive oxygen species and detoxify the phenanthrene. Glucosinolate and flavonoid biosynthesis were upregulated. The production of pinocembrin, apigenin, and epigallocatechin increased, which may play a role in antioxidation to resist phenanthrene stress. In addition, levels of six amino acids and N,N’-(p-coumaroyl)-cinnamoyl-caffeoyl-spermidine were significantly increased, which may have helped protect the plant against phenanthrene stress. These results demonstrated that S. viminalis had a positive defense strategy in response to phenanthrene challenge. Subsequent defense-related reactions may have also occurred within 24 h of phenanthrene exposure. The findings of the present study would be useful in elucidating the molecular mechanisms regulating plant responses to PAH challenges and would help guide crop and plant breeders in enhancing PAH resistance.
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•Willow tree roots were exposed to the polycyclic aromatic hydrocarbon phenanthrene.•Thirteen amino acids were upregulated for serving as precursors and osmoregulation.•Three carbohydrates were upregulated to supply energy to resist PAH stress.•Glutathione production was enhanced to scavenge ROS and detoxification.•Glucosinolate and flavonoids were upregulated to fortify plant PAH resistance.
Objective To explore the effect of mindfulness training on anxiety symptom of Chinese college students with high anxiety and its internal mechanism. Methods A total of 2 416 college students from two ...universities in Beijing were evaluated and recruited according to their scores. They were divided into intervention group and control group with twenty in each. All students were pre-tested by State-trait Anxiety Inventory Questionnaire (STAI) and the Five-factor Mindfulness Questionnaire (FFMQ). After that, students in the intervention group received an 8-week training of mindfulness cognitive therapy. After the training, all students were post-tested with the same scales. Results Mindfulness training reduced state anxiety (F=6.21, P＜0.001) and trait anxiety scores (F=6.15, P＜0.001) in the intervention group, improved their total score of mindfulness (F=6.26, P＜0.001), observation (F=5.21, P＜0.01), description (F=6.24, P＜0.001) and non-response(F=5.80, P＜0.01). Conclusions Mindfulness training effectively reduce
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