Molecular-scale controllable conversion of biopolymers into hard carbons towards lithium and sodium ion batteries: A review

Hard carbons are widely investigated as potential anodes for lithium and sodium ion batteries owing to their internally well-tailored textures(closed pores and defects) and large microcrystalline interlayer spacing. The renewable biomass is a green and economically attractive carbon source to produce hard carbons. However, the chemical and structural complexity of biomass has plagued the understanding of evolution mechanism from organic precursors to hard carbons and the structure-property relationship.This makes it difficult to finely tune the microstructure of biomass-derived hard carbons, thus greatly restricting their high-performance applications. Most recently, the optimal utilization and controllable conversion of biomass-derived biopolymers(such as starch, cellulose and lignin) at the molecular level have become a burgeoning area of research to develop hard carbons for advanced batteries.Considering the principal source of carbonaceous materials is from biomass pyrolysis, we firstly overview the chemical structures and pyrolysis behaviors of three main biopolymers. Then, the controllable preparation of hard carbons using various physicochemical properties of biopolymers at the molecular level is systematically discussed. Furthermore, we highlight present challenges and further opportunities in this field. The Review will guide future research works on the design of sustainable hard carbons and the optimization of battery performance.

Growth of high quality InSb thin films on GaAs substrates by molecular beam epitaxy method with AlInSb/GaSb as compound buffer layers

A series of In Sb thin films were grown on Ga As substrates by molecular beam epitaxy(MBE).Ga Sb/Al In Sb is used as a compound buffer layer to release the strain caused by the lattice mismatch between the substrate and the epitaxial layer,so as to reduce the system defects.At the same time,the influence of different interface structures of Al In Sb on the surface morphology of buffer layer is explored.The propagation mechanism of defects with the growth of buffer layer is compared and analyzed.The relationship between the quality of In Sb thin films and the structure of buffer layer is summarized.Finally,the growth of high quality In Sb thin films is realized.

Effects of shear stress on differentiation of stem cells into endothelial cells

Stem cell transplantation is an appealing potential therapy for vascular diseases and an indispensable key step in vascular tissue engineering.Substantial effort has been made to differentiate stem cells toward vascular cell phenotypes,including endothelial cells(ECs)and smooth muscle cells.The microenvironment of vascular cells not only contains biochemical factors that influence differentiation but also exerts hemodynamic forces,such as shear stress and cyclic strain.More recently,studies have shown that shear stress can influence the differentiation of stem cells toward ECs.A deep understanding of the responses and underlying mechanisms involved in this process is essential for clinical translation.This review highlights current data supporting the role of shear stress in stem cell differentiation into ECs.Potential mechanisms and signaling cascades for transducing shear stress into a biological signal are proposed.Further study of stem cell responses to shear stress will be necessary to apply stem cells for pharmacological applications and cardiovascular implants in the realm of regenerative medicine.

Analysis of sleep characteristics and clinical outcomes of 139 adult patients with infective endocarditis after surgery

BACKGROUND Little is known about the postoperative sleep quality of infective endocarditis patients during hospitalization and after discharge.AIM To investigate the sleep characteristics of infective endocarditis patients and to identify potential risk factors for disturbed sleep quality after surgery.METHODS The Pittsburgh Sleep Quality Index(PSQI)and the Epworth Sleepiness Scale were used to assess patient sleep quality.Logistic regression was used to explore the potential risk factors.RESULTS The study population(n=139)had an average age of 43.40±14.56 years,and 67.6%were men(n=94).Disturbed sleep quality was observed in 86 patients(61.9%)during hospitalization and remained in 46 patients(33.1%)at 6 mo after surgery.However,both PSQI and Epworth Sleepiness Scale scores showed significant improvements at 6 mo(P<0.001 and P=0.001,respectively).Multivariable logistic regression analysis showed that the potential risk factors were age(odds ratio=1.125,95%confidence interval:1.068-1.186)and PSQI assessed during hospitalization(odds ratio=1.759,95%confidence interval:1.436-2.155).The same analysis in patients with PSQI≥8 during hospitalization suggested that not using sleep medication(odds ratio=15.893,95%confidence interval:2.385-105.889)may be another risk factor.CONCLUSION The incidence of disturbed sleep after infective endocarditis surgery is high.However,the situation improves significantly over time.Age and early postoperative high PSQI score are risk factors for disturbed sleep quality at 6 mo after surgery.

Quantum entanglement dynamics based on composite quantum collision model

By means of composite quantum collision models,we study the entanglement dynamics of a bipartite system,i.e.,two qubits S1 and S2 interacting directly with an intermediate auxiliary qubit SA,while SA is in turn coupled to a thermal reservoir.We are concerned with how the intracollisions of the reservoir qubits influence the entanglement dynamics.We show that even if the system is initially in the separated state,their entanglement can be generated due to the interaction between the qubits.In the long-time limit,the steady-state entanglement can be generated depending on the initial state of S1 and S2 and the environment temperature.We also study the dynamics of tripartite entanglement of the three qubits S1,S2,and SA when they are initially prepared in the GHZ state and separated state,respectively.For the GHZ initial state,the tripartite entanglement can be maintained for a long time when the collision strength between the environment qubits is sufficiently large.

Correlation of anxiety state with blood glucose control, microinflammation and oxidative stress in patients with type 2 diabetes mellitus

Objective:To study the correlation of anxiety state with blood glucose control, microinflammation and oxidative stress in patients with type 2 diabetes mellitus.Methods:A total of 138 patients with type 2 diabetes mellitus were divided into the non-anxiety group (n=43) (SAS score < 50 points), mild-to-moderate anxiety group (n=71) (SAS score 50-69 points) and severe anxiety group (n=24) (SAS score 70 points) according to the self-rating anxiety scale (SAS) score. The differences in levels of glucose metabolism indexes, microinflammation indexes and oxidative stress indexes were compared among the three groups.Results: Peripheral blood FPG, P2hPG, HOMA-IR, CRP, ASAA, IL-6, MDA and ROS levels of mild-to-moderate anxiety group and severe anxiety group were higher than those of non-anxiety group while CAT and GSH-Px contents were lower than those of non-anxiety group;peripheral blood FPG, P2hPG, HOMA-IR, CRP, ASAA, IL-6, MDA and ROS levels of severe anxiety group were higher than those of mid-to-moderate anxiety group while CAT and GSH-Px contents were lower than those of mid-to-moderate anxiety group.Conclusion:The increase of anxiety in patients with type 2 diabetes mellitus is a direct factor leading to the abnormal glucose metabolism as well as the aggravation of microinflammatory state and oxidative stress state.

重庆某三甲医院2011年-2017年住院患者医院感染现患率调查

目的了解重庆市某三甲医院住院患者医院感染现患率及其变化趋势,为有效预防和控制医院感染提供科学依据。方法采用横断面调查的方法,从2011年-2017年连续7年对重庆市涪陵中心医院住院患者医院感染现患率进行调查与分析。结果7年共调查住院患者8663例,发生医院感染427例、483例次,感染现患率为4.93%、例次感染率为5.58%;7年感染科室均以重症医学科等为主;感染部位以下呼吸道为主;病原微生物检出率67.68%,前5位病原微生物以鲍曼不动杆菌、肺炎克雷伯菌、铜绿假单胞菌、大肠埃希菌、真菌为主,其中大肠埃希菌的检出率呈下降趋势,肺炎克雷伯菌和鲍曼不动杆菌的检出率呈上升趋势;抗菌药物平均使用率为30.77%,预防性用药比例呈下降趋势,联合用药均以一联单用为主。结论在横断面调查的基础上,要加强临床医师对相关专业知识的培训,增强医务人员医院感染预防控制的观念,做好监测工作,健全监测制度,完善监测体系,使医院感染率控制在较低水平。

幽门螺杆菌感染对内镜检出早期胃癌及癌前病变的影响

目的探讨幽门螺杆菌(Hp)感染对早期胃癌(EGC)及癌前病变部位、胃黏膜表现及内镜诊断的影响。方法回顾性分析2018年1月1日-2020年12月31日该院行白光内镜检查(WLE)和Hp检测的1107例患者的临床资料,分为Hp阴性组(608例)和Hp阳性组(499例)。以病理结果为诊断EGC及癌前病变的金标准,分析Hp感染对EGC及癌前病变部位、内镜下表现及诊断的影响。结果Hp阳性组中,检出EGC及癌前病变64例,病变以胃窦(45.31%)及胃体(26.56%)多见。Hp阴性组中,检出EGC及癌前病变62例,病变以胃窦(37.10%)及贲门(37.10%)多见。WLE下观察,存在结节或隆起、充血、糜烂及溃疡为Hp阴性EGC及癌前病变的独立危险因素,而存在结节或隆起、糜烂及溃疡为Hp阳性EGC及癌前病变的独立危险因素。虽溃疡为EGC及癌前病变的最强危险因素,但Hp阴性组OR值为26.86,高于Hp阳性组的14.43。进一步分析Hp感染对WLE诊断EGC及癌前病变的影响,Hp阳性组的灵敏度为78.13%,特异度为82.99%,均低于Hp阴性组的80.95%及87.91%。绘制WLE诊断不同Hp状态EGC及癌前病变的受试者操作特征曲线(ROC曲线),Hp阴性组的ROC曲线下面积(AUC)为0.79,高于Hp阳性组的0.74。结论Hp感染不仅可改变EGC及癌前病变的发病部位,亦可影响WLE下病变黏膜表现,进而增加诊断EGC及癌前病变的难度。

High Level Expression of Grass Carp Reovirus VP7 Protein in Prokaryotic Cells

Sequences analysis revealed Grass carp reovirus (GCRV) s10 was 909 nucleotides coding a 34 kDa protein denoted as VP7, which was determined to be a viral outer capsid protein (OCP). To obtain expressed OCP in vitro, a full length VP7 gene was produced by RT-PCR amplification, and the amplified fragment was cloned into T7 promoted prokaryotic expression vector pRSET. The recombinant plasmid,which was named as pR/GCRV-VP7,was then transformed into E.coli BL21 host cells. The data indicated that the expressed recombinant was in frame with the N-terminal fusion peptide. The over-expressed fusion protein was produced by inducing with IPTG, and its molecular weight was about 37kDa, which was consistent with its predicted size. In addition, the fusion protein was produced in the form of the inclusion body with their yield remaining steady at more than 60% of total bacterial protein. Moreover,the expressed protein was able to bind immunologically to anti-his-tag monoclonal antibody (mouse) and anti-GCRV serum (rabbit). This work provides a research basis for further structure and function studies of GCRV during entry into cells.

Improvement of carbothermic reduction of nickel slag by addition of CaCO3

The effect of CaCO3 addition on the carbothermic reduction of nickel slag was studied,and the mechanism of CaCO3 in improving the reduction was analyzed.The results showed that when the CaCO3 content added to the slag was increased from 0 to 8 wt.%,initiation temperature of the carbothermic reaction decreased from 1100 to 1000℃,the temperature reaching the maximum reduction rate decreased from 1150 to 1100℃,and the reduction degree of the nickel slag increased from 58%to 88%.The iron particles in the reduced nickel slag were coarsened and the X-ray diffraction intensity of metallic iron peaks increased,confirming that the addition of CaCO3 was beneficial to the reduction of nickel slag and recovery of iron.

Effect of B_(2)O_(3) content on viscosity and structure of SiO_(2)−MgO−FeO-based slag

The effect of B_(2)O_(3) content on the viscosity of SiO_(2)−MgO−FeO-based molten slag system was investigated using the rotating cylinder method.The evolution process of the melt structure under different contents of B_(2)O_(3) was comprehensively studied via FTIR spectroscopy and a model for calculating the degree of polymerization was developed.The results showed that the viscosity of the molten slag decreased with the addition of B_(2)O_(3),which had a slight effect when its content exceeded 3 wt.%.As the addition of B_(2)O_(3) increased from 0 to 4 wt.%,the break temperature of the slags decreased from 1152 to 1050℃ and the apparent activation energy decreased from 157.90 to 141.84 kJ/mol.The addition of B_(2)O_(3) to the molten slag destroyed the chain silicate structure to form a more cyclic borosilicate structure.The Urbain model was improved to calculate the viscosity of the SiO_(2)−MgO−FeO-based slags,and the values were in good agreement with the experimentally measured values.

Beneficial effect of berberine on atherosclerosis based on attenuating vascular inflammation and calcification

OBJECTIVE To investigate the beneficial effect of berberine(BBR)on atherosclerosisin Apo^(-/-) E mice and explore the underlying mechanisms based on attenuating vascular inflammation and modulating calcification in human umbilical vein endothelial cells(HUVECs) and smooth muscle cells(SMCs).METHODS 48 Apo-/-E mice,at 6-8 weeks old,were randomly allocated into 4 groups:normal,model,bbr and atorvastatin(positive control) groups with 12 mice in each group.They were fed with high-fat diet for 4 weeks except those in Normal group and then treated with indicated drugs orsolvent for another 4 weeks.The morphology and inflammation infiltration of aortic were examined with HE staining.The expression of BMP-2 in aortic was examined by immumohistochemical staining.Blood lipid levels were examined by automatic biochemical analyzer.The expression of IL-6,TNF-α and BMP-2 in serum and tissues was detected by ELISA method.The expression of ALP and the content of calcium were detected by commercially-available kits.HUVEC cells were stimulated with TNF-α and incubated with various concentrations of BBR for 24 h.The contents of intercellular cell adhesion molecule-1(ICAM-1),vascular cell adhesion molecule(VCAM-1),matrix metalloprotein-9(MMP-9) in the culture supernatant were detected by ELISA method.Calcification was induced with β-glycerophosphatein SMC cells and the effect of BBR on the content of calcium was examined.RESULTS 4-week berberine treatment markedly lowered serum TC and LDL-c levels and improved the plaque stability in Apo-/-E mice fed with a high-fat diet(P<0.05 or P<0.01) which was comparable with the effect of atorvastatin.Berberineal so significantly decreased the levels of IL-6 and TNF-α in mice serum and aortic tissues(P<0.05 or P<0.001).Berberine tended to decrease ALP,BMP-2 levels and the content of calcium in mice serum and aortic tissues(P<0.05,P<0.01 or P<0.001) which were not observed in atorvastatin group.Berberine significantly lowered the levels of ICAM-1,VCAM-1,and MMP-9 in TNF-α-stimulated HUVECs.It can also lowered the content of calcium in SMCs.CONCLUSION BBR can profitably regulate the levels of blood lipid in mice fed with a high-fat diet,decrease the injury caused by inflammation,and attenuate vascular calcification.It may improve atherosclerosis and play a role in cardiovascular protection.

Relationship between catecholamine level and gene polymorphism of β1 adrenergic receptor G1165C in children with EV71 infection in hand foot and mouth disease

Objective:To investigate the relationship between the levels of plasma adrenaline and norepinephrine and gene polymorphism of β1 adrenergic receptor G1165 C in children with enterovirus 71(EV71) infection in hand foot and mouth disease(HFMD). Methods:The polymerase chain reaction(PCR) was used to detect the expression of gene polymorphism of β1 adrenergic receptor G1165 C in vitro. The levels of plasma adrenaline and norepinephrine were measured by enzyme-linked immunosorbent assay(ELISA). Results:The plasma norepinephrine level of severe group was significantly higher than the mild group in children with EV71 infection in HFMD(P<0.05); however,the levels of plasma adrenalinein in two groups had no statistical differences(P>0.05); There was no significant difference in the distribution of β1 adrenergic receptor G1165 C genotype and allele between EV71 infection group and healthy control group(P> 0.05). Further analysis of EV71 infection group by dividing it into mild and severe groups showed that there was no significant difference in the distribution of genotype and allele between these two groups as well(P> 0.05). There was no significant difference in the levels of epinephrine and norepinephrine in different genotypes of EV71 infection group(P> 0.05),and in the levels of plasma epinephrine and norepinephrine in the mild and severe groups(P> 0.05). Conclusions:As the disease gets worse,the plasma norepinephrine level has a rising trend in children with EV71 infection in HFMD,which is an important indicator to evaluate the progress of the disease. However,the gene polymorphism of eptor G1165 C have no significant correlation,not only with the susceptibility and severit β1 adrenergic recy of EV71 infection in hand,foot and mouth disease,but also with the levels of catecholamine.

Effect of coronary artery revascularization on in-hospital outcomes and long-term prognoses in acute myocardial infarction patients with prior ischemic stroke

Objective To investigate whether coronary artery revascularization therapies （CART）, including percutaneous coronary intervention （PCI） and coronary artery bypass grafting （CABG）, can improve the in-hospital and long-term outcomes for acute myocardial infarction （AMI） patients with prior ischemic stroke （IS）. Methods A total of 387 AMI patients with prior IS were enrolled consecutively from January 15, 2005 to December 24, 2011 in this cohort study. All patients were categorized into the CART group （n = 204） or the conservative medications （CM） group （n = 183）. In-hospital cardiocerebral events and long-term mortality of the two groups after an average follow-up of 36 months were recorded by Kaplan-Meier survival curves and compared by Logistic regression and the Cox regression model. Results The CART patients were younger （66.5 ± 9.7 years vs. 71.7 ± 9.7 years, P 〈 0.01）, had less non-ST segment elevation myocardial infarction （11.8% vs. 20.8%, P = 0.016） and more multiple-vascular coronary lesions （50% vs. 69.4%, P = 0.031）. The hospitalization incidence of cardiocerebral events in the CART group was 9.3% while 26.2% in the CM group （P 〈 0.01）. CART significantly reduced the risk of in-hospital cardiocerebral events by 65% [adjusted odds ratio （OR） = 0.35, 95% CI： 0.13-0.92]. By the end of follow-up, 57 cases （41.6%） died in CM group （n = 137） and 24 cases （12.2%） died in CART group （n = 197）. Cox regression indicated that CART decreased the long-term mortality by 72% [adjusted hazard ratio （HR） = 0.28, 95% CI： 0.064）.46], while categorical analysis indicated no s{gnificant dif- ference between PCI and CABG. Conclusions CART has a significant effect on improving the in-hospital and long-term prognoses for AMI patients with prior IS.

Effects of smartphone-based interventions and monitoring on bipolar disorder:A systematic review and meta-analysis

BACKGROUND Recently,there has been a range of studies about smartphone-based interventions and monitoring for reducing symptoms of bipolar disorder(BD).However,their efficacy for BD remains unclear.AIM To compare the effect of smartphone-based interventions and monitoring with control methods in treating patients with BD.METHODS A systematic literature search was performed on PubMed,Embase,Clinical trials,psycINFO,Web of Science,and Cochrane Library.Randomized clinical trials(RCTs)or single-group trials in which smartphone-based interventions and monitoring were compared with control methods or baseline in patients with symptoms of BD were included.Data were synthesized using a random-effects or a fixed-effects model to analyze the effects of psychological interventions and monitoring delivered via smartphone on psychiatric symptoms in patients with BD.The primary outcome measures were set for mania and depression symptoms.Subgroups were created to explore which aspects of smartphone interventions are relevant to the greater or lesser efficacy of treating symptoms.RESULTS We identified ten articles,including seven RCTs(985 participants)and three single-group trials(169 participants).Analysis of the between-group study showed that smartphone-based interventions were effective in reducing manic[g=-0.19,95%confidence interval(CI):-0.33 to-0.04,P=0.01]and depressive(g=-0.28,95%CI:-0.55 to-0.01,P<0.05)symptoms.In within-group analysis,smartphone-based interventions significantly reduced manic(g=0.17,95%CI:0.04 to 0.30,P<0.01)and depressive(g=0.48,95%CI:0.18 to 0.78)symptoms compared to the baseline.Nevertheless,smartphone-based monitoring systems significantly reduced manic(g=0.27,95%CI:0.02 to 0.51,P<0.05)but not depressive symptoms.Subgroup analysis indicated that the interventions with psychoeducation had positive effects on depressive(g=-0.62,95%CI:-0.81 to-0.43,P<0.01)and manic(g=-0.24,95%CI:-0.43 to-0.06,P=0.01)symptoms compared to the controlled conditions,while the interventions without psychoeducation did not(P>0.05).The contacts between therapists and patients that contributed to the implementation of psychological therapy reduced depression symptoms(g=-0.47,95%CI:-0.75 to-0.18,P=0.01).CONCLUSION Smartphone-based interventions and monitoring have a significant positive impact on depressive and manic symptoms of BD patients in between-group and within-group analysis.

Randomized trial estimating effects of hypnosis versus progressive muscle relaxation on medical students’test anxiety and attentional bias

BACKGROUND Test anxiety is prevalent among medical students and leads to impaired academic performance.Test-related attentional bias has been identified as an important maintaining factor in test-anxious individuals.AIM To evaluate whether hypnosis and progressive muscle relaxation(PMR)could modify medical college students’test anxiety and attentional bias.METHODS A total of 598 medical students were screened.The participants were divided into higher and lower test anxiety groups according to their scores on the test anxiety scale(TAS).Ninety medical college students with high TAS score were randomly assigned to a hypnosis or PMR group.Another 45 students with low TAS score were included,forming a baseline control group.The intervention was conducted weekly for 6 wk,and each session lasted approximately 30 min.The total intervention time and the number of intervention sessions for the hypnosis and PMR groups were equal.Data were collected at the pretest,posttest,and 2-mo follow-up.RESULTS Hypnosis group participants had a significantly lower TAS score at posttest(t=-21.827,P<0.001)and at follow-up(t=-14.824,P<0.001),compared to that at pretest.PMR group participants also had a significantly lower TAS score at posttest(t=-10.777,P<0.001)and at follow-up(t=-7.444,P<0.001),compared to that at pretest.At the posttest level,the hypnosis group had a significantly lower TAS score than the PMR group(t=-3.664,P<0.001).At the follow-up level,the hypnosis group also had a significantly lower TAS score than the PMR group(t=-2.943,P=0.004).Clinically significant improvement was found in both the hypnosis and PMR groups(hypnosis=64.0%;PMR=62.22%).Hypnosis was more effective than PMR in reducing test anxiety among medical college students.Hypnosis could modify attentional bias toward threatening stimuli,but PMR could not.CONCLUSION These results suggest that attentional bias plays an important role in test anxiety treatment.

Phosphorylation of KAT-2B by WKS1/Yr36 redirects the lipid flux to jasmonates to enhance resistance against wheat stripe rust

Wheat(Triticum aestivum)is one of the most essential human energy and protein sources.However,wheat production is threatened by devastating fungal diseases such as stripe rust,caused by Puccinia striiformis Westend.f.sp.tritici(Pst).Here,we reveal that the alternations in chloroplast lipid profiles and the accumulation of jasmonate(JA)in the necrosis region activate JA signaling and trigger the host defense.The collapse of chloroplasts in the necrosis region results in accumulations of polyunsaturated membrane lipids and the lipid-derived phytohormone JA in transgenic lines of Yr36 that encodes Wheat Kinase START 1(WKS1),a high-temperature-dependent adult plant resistance protein.WKS1.1,a protein encoded by a full-length splicing variant of WKS1,phosphorylates and enhances the activity of keto-acyl thiolase(KAT-2B),a critical enzyme catalyzing theβ-oxidation reaction in JA biosynthesis.The premature stop mutant,kat-2b,accumulates less JA and shows defects in the host defense against Pst.Conversely,overexpression of KAT-2B results in a higher level of JA and limits the growth of Pst.Moreover,JA inhibits the growth and reduces pustule densities of Pst.This study illustrates the WKS1.1-KAT-2B-JA pathway for enhancing wheat defense against fungal pathogens to attenuate yield loss.

Pyrometallurgical recycling of stainless steel pickling sludge: a review

Stainless steel pickling sludge (SSPS), generated from the lime neutralization process of spent pickling liquor, is classified as a hazardous waste consisting of abundant metals like Fe, Cr and Ni, and other elements like F, S and Na, etc. Rather than a common disposal in landfill, recovering these metals and other valuable components from SSPS can not only create economic benefits, but also eliminate its adverse impacts on human health and the environment. A review of the formation mechanism and basic properties of SSPS was made, and the technical features, advantages and limitations of a series of pyrometallurgical treatment processes were summarized. Based on these, the main challenges for recycling of SSPS through the existing techniques are demonstrated. The traditional pelletizing/sintering-blast furnace process can only be used as a partial solution. Direct use of SSPS as flux in an argon-oxygen decarburization converter or electric arc furnace is a promising way, but low S sludges are preferred. The STAR process shows excellent recovery for metals, but it also has a low tolerance to the S and F contents in SSPS. And theINMETCO process is highly flexible in treatment of various wastes, whereas it exhibits relatively low Cr recovery and produces poor-quality pig iron. In addition, the feasibility of the rotary kiln-electric furnace, solid -state reduction of chromite and reduction-magnetic separation processes requires further studies. An urgent task at present is to develop a system for scientific classification and separate collection of SSPS in terms of chemical composition, notably S and F contents.

One-pot ball-milling preparation of graphene/carbon black aqueous inks for highly conductive and flexible printed electronics

Stable aqueous carbon inks,with graphene sheets(GSs)and carbon black(CB)as conductive fillers,are prepared by a simple one-pot ball-milling method.The asprepared composite ink with 10 wt%GSs shows optimized rheological properties(viscosity and thixotropy)for screen printing.The as-printed coatings based on the above ink are uniform and dense on a polyimide substrate,and exhibit a sandwich-type conductive three dimensional network at the microscale.The resistivity of the typical composite coating is as low as 0.23±0.01Ωcm(92±4Ωsq^-1,25μm),which is 30%as that of a pure CB coating(0.77±0.01Ωcm).It is noteworthy that the resistivity decreases to 0.18±0.01Ωcm(72±4Ωsq^-1,25μm)after a further rolling compression.The coating exhibits good mechanical flexibility,and the resistance slightly increases by 12%after 3000 bending cycles.With the CB/GSs composite coatings as a flexible conductor,fascinating luminescent bookmarks and membrane switches were fabricated,demonstrating the tremendous potential of these coatings in the commercial production of flexible electronics and devices.

Volatilization behaviour and volatilization kinetics of CaF2-Na2O-CaOSiO2-Al2O3-MgO-B2O3 synthetic mould flux

To reduce the volatilization of the volatile-containing slags and obtain accurate measurement results of slag performance,the volatility degree and deviation mechanism must be determined.Non-isothermal thermogravimetric analysis at different heating rates was used to establish the volatilization kinetic model,and it reveals the volatilization mechanism of CaF2-Na2O-CaO-SiO2-Al2O3-MgO-B2O3 synthetic sodium-containing fluoride mould flux.The results demonstrated that the evaporation of NaF and SiF4 was the decisive factor that led to the change in composition and deviation of properties of the tested slags.The most probable kinetic mechanism function for the evaporation of volatile component from sodiumcontaining fluoride mould flux could be expressed by g(α)=[—ln(1-α)]^2/3,with an apparent activation energy of 164.866 kJ mol^-1 and pre-exponential factor of 2.13×10^-4 s^-1,where α is the conversion rate at any time step in the volatilization process.The reaction mechanism was random nucleation followed by growth,which was the limiting factor for the volatilization of synthetic sodium-containing fluoride mould flux.The method of increasing heating rate and adding protection gas in the measurement system will help to obtain more accurate results of slag performance.