Carboxylic bacterial cellulose fiber-based hydrogel electrolyte with imidazole-type ionic liquid for dendrite-free zinc metal batteries

Aqueous zinc metal batteries are regarded as the most promising energy storage system due to their advantages of high safety,low cost,and high theoretical capacity.However,the growth of dendrites and the occurrence of side reactions hinder the development of zinc metal batteries.Despite previous attempts to design advanced hydrogel electrolytes,achieving high mechanical performance and ionic conductivity of hydrogel electrolytes has remained challenging.In this work,a hydrogel electrolyte with an ionic crosslinked network is prepared by carboxylic bacterial cellulose fiber and imidazole-type ionic liquid,following by a covalent network of polyacrylamide.The hydrogel electrolyte possesses a superior ionic conductivity of 43.76 mS cm^(−1),leading to a Zn^(2+)migration number of 0.45,and high mechanical performance with an elastic modulus of 3.48 GPa and an elongation at breaking of 38.36%.More importantly,under the anion-coordination effect of the carboxyl group in bacterial cellulose and[BF4]−in imidazole-type ionic liquid,the solvation sheath of hydrated Zn^(2+)ions and the nucleation overpotential of Zn plating are regulated.The results of cycled testing show that the growth of zinc dendrites is effectively inhibited and the generation of irreversible by-products is reduced.With the carboxylic bacterial cellulose-based hydrogel electrolyte,the Zn||Zn symmetric batteries offer good cyclability as well as Zn||Ti batteries.

ESG表现如何提升企业市场势力——来自上市公司的证据

随着逐渐束紧的可持续发展要求,企业的经营理念已发生深刻变化。高质量的企业发展意味着,企业需将环境、社会和治理理念融入企业决策中,那么企业的社会、环境和治理能力能否增强企业市场竞争力,提升企业市场势力?为此,本文尝试探究ESG表现对企业市场势力的影响及其作用机制,并利用2010—2019年沪深A股上市公司数据展开检验。研究结果表明,ESG表现显著而稳健地促进企业市场势力的提升。异质性分析表明,不同生命周期及不同产权、行业属性的企业,其作用效果有所不同,具体而言,对于处于成长期、国有、非重污染企业,ESG表现对于市场势力的提升效果更好。机制分析表明,ESG表现通过降低企业交易成本、提高企业生产效率、强化风险承担能力等渠道提升市场势力。文章的研究结论对企业根据自身发展阶段,做好战略决策、提升企业ESG管理水平、促进国家经济高质量发展具有启示。

The migration of total dissolved solids during natural freezing process in Ulansuhai Lake

High total dissolved solids （TDS） content is one of the most important pollution contributors in lakes in arid and semiarid areas. Ulansuhai Lake, located in Urad Qianqi, Inner Mongolia, China, was selected as the object of study. Temperatures and TDS contents of both ice and under-ice water were collected together with corresponding ice thickness. TDS profiles were drawn to show the distribution of TDS and to describe TDS migration. The results showed that about 80% （that is 3.602x108 kg） of TDS migrated from ice to water during the whole growth period of ice. Within ice layer, TDS migration only occurred during initial ice-on period, and then perished. The TDS in ice decreased with increasing ice thickness, following a negative exponential-like trend. Within un- der-ice water, the TDS migrated from ice-water interface to the entire water column under the effect of concentra- tion gradient until the water TDS content was uniform. In winter, 6.044x 107 kg （16.78% of total TDS） TDS migrated from water to sedirnent, which indicated that winter is the best time for dredging sediment. The migration effect gives rise to TDS concentration in under-ice water and sediment that is likely to affect ecosystem and water quality of the Yellow River. The trend of transfer flux of ice-water and water-sediment interfaces is similar to that of ice growth rate, which reveals that ice growth rate is one of the determinants of TDS migration. The process and mechanism of TDS migration can be referenced by research on other lakes with similar TDS content in cold and arid areas.

APOE and APOC1 gene polymorphisms are associated with cognitive impairment progression in Chinese patients with late-onset Alzheimer's disease

Current evidence shows that apolipoprotein E （APOE）, apolipoprotein CI （APOC1） and low density lipoprotein receptor-related protein （LRP） variations are related to late-onset Alzheimer＇s disease. However, it remains unclear if genetic polymorphisms in these genes are associated with cognitive decline in late-onset Alzheimer＇s disease patients. We performed a 30-month longitudi- nal cohort study to investigate the relationship between Alzheimer＇s disease and APOE, APOC1, and LRP. In this study, 78 Chinese Han patients with late-onset Alzheimer＇s disease were recruit- ed form Guangxi Zhuang Autonomous Region in China. APOE, APOC1, and LRP genotyping was performed using polymerase chain reaction-restriction fragment length polymorphisms. The Mini-Mental State Examination and Clinical Dementia Rating Scale were used to assess pa- tients＇ cognitive function. After a 30-month follow-up period, we found a significant reduction in Mini-Mental State Examination total score, a higher proportion of patients fulfilling cognitive impairment progression criteria, and a higher proportion of APOC1 H2 carriers in APOE 4 carriers compared with non-carriers. In addition, the APOE 4 allele frequency was significantly higher in the cognitive impairment progression group compared with the non-cognitive im- pairment progression group. In conclusion, APOE e4 plays an important role in augmenting cognitive decline, and APOC1 H2 may act synergistically with APOE ~4 in increasing the risk of cognitive decline in Chinese patients with late-onset Alzheimer＇s disease.

Application of gas wettability alteration to improve methane drainage performance:A case study

Hydraulic fracturing technique is widely used for methane drainage and has achieved good effects in numerous coal mines,but negative effects may occur as the fracturing fluids are absorbed into the coal seam.Gas wettability alteration(GWA)technology can be used as it can enhance the gas and water mobility during dewatering process as a result of capillary pressure change.However,there have been few reported field tests in coal mines using GWA technology.This paper describes a pilot-scale field test in Xinjing coal mine,Yangquan,China.The fluorocarbon surfactants perfluorooctyl methacrylate monomer-containing polymethacrylate(PMP)was used to alter the wettability of coal seam to strong gas-wetness during the hydraulic fracturing process.The study focuses on the comparison of two boreholes(Boreholes#9 and#10)and one other borehole(Borehole#8)with and without using GWA approach.A well-defined monitoring program was established by measuring the dewatering volume of the fracturing fluid and the drainage volume of methane as well as the concentration.The field test results showed that the average methane drainage rates of Boreholes#9(39.28 m^(3)/d)and#10(51.04 m^(3)/d)with GWA treatment exceeded that of Borehole#8(21.09 m^(3)/d)without GWA treatment,with an increase of 86.3%and 142.1%,respectively.The average methane concentrations of Boreholes#9(4.05%)and#10(6.18%)were 64.6%and 151.2%higher than that of Borehole#8(2.46%),respectively.On the other hand,the dewatering ratio of Boreholes#9(4.36%)and#10(3.11%)was almost 19 times and 13 times greater than that of Borehole#8(0.22%).These field test results were in agreement with the experimental data.The significant increase in both methane concentration and dewatering ratio demonstrated that GWA technology could be applied for enhanced methane drainage in coal mines.Important lessons learned at Xinjing coal mine might be applied to other coal mines in China and elsewhere.

A High Efficiency Spread Spectrum Scheme Using Approximate Orthogonal Complex Sequences

This paper presents a high efficiency spread spectrum scheme using approximate orthogonal complex (AOC) sequences. In this scheme, the 64 AOC sequences picked up from 84 complex sequences space are employed for spreading spectrum. In modulation, 6 input bits is used to select one AOC sequence, and the selected sequence is then phase-rotated by another 2 input bits. In demodulator, a complex correlator detects the transmitted AOC sequence. Simulation results show that the proposed scheme has better BER performance than the existing complementary code keying (CCK) modulation scheme. For AOC, additional processing gain of 1.79dB can be obtained when the sequence length is 8.

The Course Reform and Internet Teaching of New Inorganic Materials

With the continuous demand of material performance,the development of materials is rapid,and the professional curriculum teaching of“new inorganic materials”as well as its teaching methods related to the internet mandate a reform,in order to meet the needs of innovative high-quality personnel training.The update and optimization of the teaching content and methods assisted by the internet meet the needs of modern teaching and research work.More than 90%of students believe that internet teaching is conducive to the understanding of classroom knowledge and the development of innovative projects.

Impact of HBV replication in peripheral blood mononuclear cell on HBV intrauterine transmission

This study determined the effect of hepatitis B virus （HBV） replication in peripheral blood mononuclear cell （PBMC） from HBsAg-positive mothers on HBV intrauterine transmission. A total of 150 HBsAg- positive mothers and their neonates were recruited in this study. Within 24 h after birth, HBV serological markers, serum HBV DNA, PBMC HBV relaxed circular DNA （rcDNA）, and covalently closed circular DNA （cccDNA） were measured in the HBsAg-positive mothers and their neonates before passive-active immune prophylaxis. The relationship between HBV replication in PBMC and HBV intrauterine transmission was examined through Chi- square test and logistic regression. The rate of HBV intrauterine transmission was 8.00% （12/150） in the 150 neonates born to HBsAg-positive mothers. The positivities of PBMC HBV rcDNA and cceDNA in the HBsAg- positive mothers were 36.67% （55/150） and 10% （15/150）, respectively. Maternal PBMC HBV cccDNA was a risk factor of HBV intrauterine transmission （OR = 6.003, 95% Ch 1.249-28.855）. Maternal serum HBeAg was a risk factor of PBMC HBV rcDNA （OR = 3.896, 95% CI： 1.929-7.876） and PBMC HBV cccDNA （OR = 3.74, 95% CI： 1.186--11.793） in the HBsAg-positive mothers. Administration of hepatitis B immune globulin was a protective factor ofPBMC HBV cccDNA （OR = 0.312, 95% CI： 0.102-0.954） during pregnancy. The positivity ofPBMC HBV rcDNA was related to that of cccDNA in the HBsAg-positive mothers （Zz= 5.087, P = 0.024）. This study suggests that PBMC is a reservoir of HBV and an extrahepatic site for virus replication and plays a critical role in HBV intrauterine transmission.

Mullite Oxidation Resistant Coating for SiC-coated Carbon/Carbon Composites by Supersonic Plasma Spraying

To improve the oxidation resistance of carbon/carbon （C/C） composites, mullite coating was prepared on the surface of SiC-coated C/C composites by supersonic plasma spraying. Phases and microstructures of mullite coating were characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The coating primarily consists of a single phase of mullite （3AI203-2SIO2）. The SEM results show that mullite coating was continuous and well bonded with the SiC inner layer without penetrating crack. Mullite coating exhibited good oxidation resistance, After 98.5 h oxidation at 1773 K and 9 thermal shock cycles between 1773 K and room temperature, the weight loss of the coated C/C composites was only 2.57%.

Effect of SiC Location on the Ablation of C/C-SiC Composites in Two Heat Fluxes

How layer-segregated distribution of SiC affects the ablation of C/C-SiC composites was studied in the present work.A certain amount of SiC particles was deposited at the non-woven（C/C—SiC-1） and web（C/C-SiC-2） layer of 2D needle-punched carbon fibre fabric reinforced pyrocarbon composites,respectively.Ablation under oxyacetylene torch demonstrated that the two composites have similar ablation rates in heat flux of 2.38 MW/m2whereas ablation rates of C/C-SiC-2 were much higher than those of C/C—SiC-1 when heat flux was 4.18 MW/m2.SiO2covered partially the defective surface of both composites in the lower heat flux.The different SiC locations induced distinct defects and then led to the two composites’ dissimilar ablation rates in the higher heat flux.

Morphologies evolution and mechanical behaviors of SiC nanowires reinforced C/(PyC-SiC)_(n)multilayered matrix composites

SiC nanowires reinforced C/(PyC-SiC)_(n)multilayered matrix composites(SM-CS for short)were prepared by combined with sol-gel and chemical vapor infiltration(CVI)method.Firstly,(PyC-Si OC);multilayered structure was formed by cycles of impregnation and deposition.Then SiOC was transformed into SiC by heat-treatment,and(PyC-SiC)_(n)multilayered structure would be obtained.At the same time,the PyC layer which was designed as the outmost layer could decrease gas supersaturation to form in-situ tubular SiC nanowires on the surface of multilayered structure.The results of three-point bending test showed that the maximum force of SM-CS composites was increased by the number of cycles of the preparation process,which were up to enhanced by 74.38%compared with C/C composite materials.The fracture surface showed that the improvement was due to the multiscale reinforcing system of(PyC-SiC)_(n)multilayered structure and SiC nanowires.Multilayered structure can protect carbon fibers and release stress concentration by induction of cracks.And the mechanical interlocking effect of SiC nanowires could reinforce bonding force of the remaining matrix.

Effect of Bonding Temperature on the Microstructures and Strengths of C/C Composite/GH3044 Alloy Joints by Partial Transient Liquid-Phase(PTLP) Bonding with Multiple Interlayers

With the use of Ti/Ni/Cu/Ni multiple foils as interlayer,carbon/carbon（C/C） composite was bonded to Nibased superalloy GH3044 by partial transient liquid-phase bonding technique.The effect of bonding temperature on the microstructures and strengths of the joints was investigated.The results showed that gradient structural multiple interlayers composed of ‘‘C–Ti reaction layer/Ti–Ni intermetallic compound layer/Ni–Cu sosoloid/residual Cu layer/Ni-GH3044 diffusion layer＇＇ were formed between C/C composite and GH3044.The shear strength of the C/C composite/GH3044 joint reached the highest value of 26.1 MPa when the bonding temperature was 1,030 °C.In addition,the fracture morphology showed that the fracture mode changed with the increase of bonding temperature.