海泡石的活化对湿法制备天然橡胶复合材料性能的影响

为提升海泡石补强橡胶的应用效果,首先采用有机酸活化制备高活性海泡石(MSep);比表面积、X射线衍射和光电子能谱测试结果表明,MSep的晶体结构完整,比表面积和表面活性明显增强;借助橡胶加工分析仪、扫描电镜和动态力学热分析等方法研究了经湿法乳液混合制备的不同活性及用量的海泡石/天然橡胶复合材料的结构与性能。结果表明,复合材料中的MSep分散性较好,界面相互作用增强;在MSep用量小于30 phr时,随用量增多,拉伸强度和300%定伸应力等逐渐提升,硫化效率则逐渐降低;MSep用量过多时,受填料聚集的影响,综合补强性能下降;此外,随海泡石用量的增多,复合材料储能模量逐渐增大,损耗因子最大值逐渐减小。

Production of palmitoleic acid by oleaginous yeast Scheffersomyces segobiensis DSM 27193 using systematic dissolved oxygen regulation strategy

Palmitoleic acid(POA)can be naturally found only in few oil seeds and has significant applications in pharmaceutical industry.Recently,the isolated oleaginous yeast Scheffersomyces segobiensis DSM 27193 was identified with high content of POA in its intracellular lipid(13.80%).In this study,process optimization focused on dissolved oxygen regulation to improve POA production was conducted.Dynamic agitation was found to do significant enhancement on POA-rich lipid production than aeration regulation.Under the best condition of 1000 r·min^(-1)of agitation and 1 vvm(airvolume/culture volume/min)of aeration,no ethanol was detected during the whole fermentation process,while a dry biomass concentration of 44.80 g·L^(-1)with 13.43 g·L^(-1)of lipid and 2.93 g·L^(-1)of POA was achieved.Transcription analysis revealed that the ethanol synthetic pathway was downregulated under the condition of high agitation,while the expression of the key enzymes responsible for lipid and POA accumulation were enhanced.

Periodical polarization reversal modulation in multiferroic MnWO_(4) under high magnetic fields

We report polarization reversal periodically controlled by the electric field in multiferroic MnWO_(4) with a pulsed field up to 52 T.The electric polarization cannot be reversed by successive opposite electric fields in low magnetic fields(<14 T)at 4.2 K,whereas polarization reversal is directly achieved by two opposite electric fields under high magnetic fields(<45 T).Interestingly,the polarization curve of rising and falling fields for H∥u(magnetic easy axis)is irreversible when the magnetic field is close to 52 T.In this case,the rising and falling polarization curves can be individually reversed by the electric field,and thus require five cycles to recover to the initial condition by the order of the applied electric fields(+E,-E,-E,+E,+E).In addition,we find that ferroelectric phaseⅣcan be tuned from parallel to antiparallel in relation to ferroelectric phase AF2 by applying a magnetic field approximated to the c axis.

Prediction of stable BC_(3)N_(2)monolayer from first-principles calculations:Stoichiometry,crystal structure,electronic and adsorption properties

In this paper,a novel BC_(3)N_(2)monolayer has been found with a graphene-like structure using the developed particle swarm optimization algorithm in combination with ab initio calculations.The predicted structure meets the thermodynamical,dynamical,and mechanical stability requirements.Interestingly,the BC_(3)N_(2)plane shows a metallic character.Importantly,BC_(3)N_(2)has an in-plane stiffness comparable to that of graphene.We have also investigated the adsorption characteristics of CO_(2)on pristine monolayer and Mo functionalized monolayer using density functional theory.Subsequently,electronic structures of the interacting systems(CO_(2)molecule and substrates)have been preliminarily explored.The results show that Mo/BC_(3)N_(2)has a stronger adsorption capacity towards CO_(2)comparing with the pristine one,which can provide a reference for the further study of the CO_(2)reduction mechanism on the transition metal-functionalized surface as well as the new catalyst’s design.

Two-dimensional MgSiP_(2) with anisotropic electronic properties and good performances for Na-ion batteries

Using the global particle-swarm optimization method and density functional theory,we predict a new stable two-dimensional layered material:MgSiP_(2)with a low-buckled honeycomb lattice.Our HSE06 calculation shows that MgSiP_(2)is an indirect-gap semiconductor with a band-gap of 1.20 eV,closed to that of bulk silicon.More remarkably,MgSiP_(2)exhibits worthwhile anisotropy along with electron and hole carrier mobility.A ultrahigh electron mobility is even up to 1.29×10^(4)cm^(2)V^(-1)s^(-1).while the hole mobility is nearly zero along the a direction.The large difference of the mobility between electron and hole together with the suitable band-gap suggest that MgSiP_(2)may be a good candidate for solar cell or photochemical catalysis material.Furthermore,we explore MgSiP_(2)as an anode for sodium-ion batte ries.Upon Na adsorption,the semiconducting MgSiP_(2)transforms to a metallic state,ensuring good electrical conductivity.A maximum theoretical capacity of 1406 mAh/g,a small volume change(within 9.5%),a small diffusion barrier(~0.16 eV)and low average open-circuit voltages(~0.15 V)were found fo r MgSiP_(2)as an anode for sodium-ion batteries.These results are helpful to deepen the understanding of MgSiP_(2)as a nanoelectronic device and a potential anode for Na-ion batteries.

Two-dimensional 1T-PS2 as a promising anode material for sodium-ion batteries with ultra-high capacity, low average voltage and appropriate mobility

As electrodes,two-dimensio nal materials show special advantages including the infinite planar lengths,broad electrochemical window,large surface-volume ratio,and much exposed active sites.In theory,the two-dimensional materials consist of the elements with high electronegativity may absorb more Na atoms,resulting in a high battery storage capacity.Based on the above idea,we selected the two dimensional metallic PS2 with 1 T-Type structure as an anode material,and explored its potential applications as an electrode material for Na-ion battery through first-principle calculations.As we expected,when two dimensional PS2 is used as an anode in Na-ion battery,it can adsorb maximum three layers of sodium atoms on both sides of the monolayer,resulting in a maximum theoretical capacity of 1692 mAh/g.Furthermore,it also possesses a rather small sodium diffusion barrier of 0.17 eV,a low average open-circuit voltage of 0.18 V,and a relatively small lattice changes within 13% during the intercalation of Na.These results suggested that the two dimensional PS2 is a potentially excellent Na-ion battery anode.Our idea of designing two-dimensional anode materials with high storage capacity may provide some references for designing the next generation anode materials of metal-ion batteries.

iNet:visual analysis of irregular transition in multivariate dynamic networks

Multivariate dynamic networks indicate networks whose topology structure and vertex attributes are evolving along time.They are common in multimedia applications.Anomaly detection is one of the essential tasks in analyzing these networks though it is not well addressed.In this paper,we combine a rare category detection method and visualization techniques to help users to identify and analyze anomalies in multivariate dynamic networks.We conclude features of rare categories and two types of anomalies of rare categories.Then we present a novel rare category detection method,called DIRAD,to detect rare category candidates with anomalies.We develop a prototype system called iNet,which integrates two major visualization components,including a glyph-based rare category identifier,which helps users to identify rare categories among detected substructures,a major view,which assists users to analyze and interpret the anomalies of rare categories in network topology and vertex attributes.Evaluations,including an algorithm performance evaluation,a case study,and a user study,are conducted to test the effectiveness of proposed methods.

Increase in chloride from baseline is independently associated with mortality in intracerebral hemorrhage patients admitted to intensive care unit:A retrospective study

Background:Hyperchloremia is associated with increased mortality in critically ill patients.The objective of this study was to investigate the association between increased chloride levels and mortality outcomes in intracerebral hemorrhage(ICH)patients admitted to the intensive care unit(ICU).Methods:We performed a retrospective study of all patients diagnosed with ICH and included in the Medical Information Mart for Intensive Care(MIMIC-III)from 2001 to 2012.Inclusion criteria were the first diagnosis of ICH,ICU length of stay(LOS)over 72 h,and not receiving hypertonic saline treatment.Serum chloride perturbation within 72 h of admission was evaluated as a predictor of outcomes.The increase in chloride from baseline was dichotomized based on an increase in chloride in 72 h(≤5 mmol/L or>5 mmol/L).The primary outcome was 90-day mortality.Results:A total of 376 patients(54.5%male,median age 70 years,interquartile range:58–79 years)were included.The overall 90-day mortality was 32.2%(n=121),in-hospital mortality was 25.8%(n=97),and Day 2 acute kidney injury(AKI)occurred in 29.0%(n=109)of patients.The prevalence of hyperchloremia on admission,during the first 72 h,and an increase in chloride(>5 mmol/L)were 8.8%,39.4%,and 42.8%,respectively.After adjusting for confounders,the hazard ratio of increase in chloride(>5 mmol/L)was 1.66(95%confidence interval:1.05–2.64,P=0.031).An increase in chloride(>5 mmol/L)was associated with a higher odds ratio for 90-day mortality in both the AKI and non-AKI groups.Conclusions:An increase in chloride from baseline is common in adult patients with ICH admitted to ICU.The increase is significantly associated with elevated mortality.These results support the significance of diligently monitoring chloride levels in these patients.