Study on extraction phenol from coal tar with high flux centrifugal extractor

Solvent extraction phenol from coal tar were carried out with novel composite YH-3 as extraction agent, and the high flux centrifugal extractor was used as extraction device. Under the premise of high phenol extraction rate, composite YH-3 extraction agent reduces n-n interaction between phenolic compounds and aromatic hydrocarbons, thus decreasing the entrainment of neutral oil. The optimization of operation conditions, such as the diameter of heavy phase weir HWD, the flow ratio, the total flow rate and the rotation speed, are necessary. For single stage extraction experiment, the mass transfer efficiency was up to 84% while the rate of extraction agent loss was lower than 0.28% with the operation conditions of 29 mm of the heavy phase weir diameter （HWD）, 1：1-1.4：1 of the flow ratio range, 160-200 mL/min of the total flow rate and the rotation speed varied from 2200 to 2600 r/min. For three stage counter-current test, the mass transfer efficiency reached up to 92.6% with the optimum operation condition of 29 mm of the HWD, 1：1 of the flow ratio, 200 rnL/min of the total flow rate and 2400 r/rain of the rotation speed. The results indicated that phenol could be extracted effectively from coal tar in the process of multistage continuous count current centrifugal extraction.

Mechanisms and characteristics of mesocarbon microbeads prepared by co-carbonization of coal tar pitch and direct coal liquefaction residue

DCLR-P was prepared by direct coal liquefaction residue (DCLR) with ash removal.In the present experiments,mesocarbon microbeads (MCMBs) were prepared by co-carbonization of coal tar pitch (CTP) and DCLR-P.With the increase of DCLR-P content,the yield of MCMBs increased from 47.8% to 56.8%.At the same time,the particle sizes distribution of MCMBs was narrowed,resulting in the decrease of D9o/D10 ratio from 154.88 to 6.53.The results showed that DCLR-P had a positive effect on the preparation of MCMBs.1H-NMR,FTIR,SEM and XRD were used to analyze the mechanisms and characteristics of MCMBs prepared by co-carbonization of CTP and DCLR-P.The results showed that the Proton Donor Quality Index (PDQI) of DCLR-P was 13.32,significantly higher than that of CTP (0.83).This indicated that DCLR-P had more naphthenic structure than CTP,which leads to hydrogen transferring in polycondensation reaction.The aliphatic structure of DCLR-P can improve the solubility and fusibility of mesophase,thereby making the structure of MCMBs more structured.The microstructure of the graphitized MCMBs had a substantially parallel carbon layer useful for its electrical performance.The performance of graphitized MCMBs as a negative electrode material for Li-ion batteries was tested.The particle sizes,tap density,specific surface area and initial charge-discharge efficiency of graphitized MCMBs met the requirements of CMB-I in GB/T-24533-2009.However,the initial discharge capacity of graphitized MCMB was only 296.3 mA h g-1 due to the low degree of graphitization of MCMBs.

Responses of breeding waterbird communities to environmental changes in subsidence wetlands in the North China Plain

In the context of global degradation and loss of natural wetlands,waterbirds have been increasingly using artificial wetlands as alternative habitats.However,waterbirds are facing various threats in these artificial wetlands,due to dramatic environmental changes induced by anthropogenic activities.Exploring the effects of these changes on the temporal dynamics of the waterbird communities can help understand how waterbirds adapt to environmental changes and thus formulate effective management and conservation plans.In this study,we carried out field surveys on waterbirds and environmental factors across 20 subsidence wetlands created by underground coal mining in the Huainan coal mining area in the breeding seasons of 2016 and 2021.We predicted that the waterbird assemblages(i.e.,number of individuals,species richness,Shannon-Wiener diversity,Pielou evenness and species composition) differed between the two years,and that these differences were correlated with the temporal changes in environmental factors.Across the surveyed wetlands,we recorded 26 waterbird species in 2016 and 23 in 2021.For individual wetlands,the number of waterbird individuals and species richness increased by 71.6% and 20.1%,respectively,over the five years,with no changes in Shannon-Wiener diversity and Pielou evenness.The overall increase in the number of bird individuals was mainly caused by an increase in vegetation gleaners and gulls that adapt well to anthropogenic activities.The species composition was significantly different between the two years,which was mainly caused by changes in the number of individuals of dominant species under influence of changes in human activities.For most wetlands,the temporal pairwiseβ-diversities could be explained by species turnover rather than nestedness,probably due to high mobility of waterbird species and dramatic changes in local environments.Our study suggests that waterbird communities could respond to environmental changes in subsidence wetlands,providing important implications for waterbird conservation in human-dominated artificial wetlands.

Improved Qualitative Trajectory Calculus for Pair-Activity Analysis

Trajectory provides the most robust feature for activity recognition in far-field surveillance videos,in which increasing attentions have been given to the use of qualitative methods with symbolic rather than real-value features.Qualitative trajectory calculus(QTC)showed a good performance in pair-activity from video.However,QTC and similar works are not good at dealing with noise,since they are all considering short-term features.To deal with the problems mentioned above,two types of long-term features,including sub-trajectory feature and point-trajectory feature,are designed.The sub-trajectory feature is a long-term feature in a coarse granularity,while the point-trajectory feature is a long-term feature in a relatively fine granularity.Using the sub-trajectory feature,a couple of trajectories are segmented into sub-trajectories and enveloping boxes are used to substitute the original sub-trajectory for capturing the major attributes.The point-trajectory feature describes the relationship between a single point in one trajectory and all parts of the other trajectory.The experiments on the human activity classification data demonstrated that our proposed methods are better than the original QTC and previous short-term features.

Reflective optical vortex generators with ultrabroadband self-phase compensation

The explosive growth of information urgently requires extending the capacity of optical communication and information processing.Orbital-angular-momentum-based mode division multiplexing(MDM)is recognized as the most promising technique to improve the bandwidth of a single fiber.To make it compatible with the dominant wavelength division multiplexing(WDM),broadband equal high-efficient phase encoding is highly pursued.Here,we propose a twisted-liquid-crystal and rear-mirror-based design for ultrabroadband reflective planar optics.The backtracking of the light inside the twisted birefringent medium leads to an achromatic phase modulation.With this design,a single-twisted reflective q-plate is demonstrated to convert a white beam to a polychromatic optical vortex.Jones calculus and vector beam characterization are carried out to analyze the broadband phase compensation.A dual-twisted configuration further extends the working band to over 600 nm.It supplies an ultrabroadband and reflective solution for the WDM/MDMcompatible elements and may significantly promote advances in ultrabroadband planar optics.

Electrospun nanofibrous membranes with antimicrobial activity for air filtration

Air pollution,including airborne pathogens and particulate matter(PM),has become a prominent issue affecting human health and safety.Conventional air filtration materials do not meet the requirements for efficient PM capture or do not instantly kill pathogens,leading to increased risk of direct/indirect contact transmission and infection due to the accumulation of pathogens during filtration.Electrospun nanofibrous membranes have emerged as a promising platform due to their rich porous structure,finer fiber diameters,good internal connectivity,and the ability to easily incorporate active chemicals for antimicrobial function.In this review,antimicrobial mechanisms of nanofibrous membranes for air filtration and PM capture mechanisms of nanofibers were firstly investigated,and various types of electrospun nanofibrous membranes with different antimicrobial agents for efficient air filtration were described in detail,including organic antimicrobial agents,inorganic antimicrobial agents and metal-organic frameworks.We hope this work could provide a better practical insight for designing novel electrospun nanofibrous membranes with antimicrobial efficacy for efficient air filtration.

基于LS-DYNA的热成型钢断裂失效预测研究

热成型钢在汽车行业的普遍应用,为汽车轻量化及燃油经济性带来显著提升.然而热成型钢特殊的淬火硬化工艺又使得其塑性延展性显著降低.因此在整车碰撞等大变形情况下,热成型钢断裂失效的准确模拟、预测显得尤为重要.论文以宝钢B1500HS热成型钢为研究对象,通过完善的材料力学实验,获得了LS-DYNA＊MATADDEROSION模块中Damage initiation and evolution criteria（DIEC）失效模型的各个参数,并通过设计热成型B柱子系统试验对该失效模型进行验证.结果表明DIEC失效模型可以准确预测热成型钢的断裂失效行为.该研究可对早期开发阶段的车身热成型结构优化设计提供参考.

Association of elevated hs-CRP and multiple infarctions with outcomes of minor stroke or TIA: subgroup analysis of CHANCE randomised clinical trial

Background and purpose The relationship of high-sensitive C-reactive protein(hs-CRP)levels and infarction numbers with the prognosis of stroke is uncertain.This study evaluated the association of different hs-CRP levels and infarction numbers with the prognosis of acute minor ischaemic stroke or transient ischaemic attack(TIA).Methods A subset of 807 patients with both hs-CRP measurement and baseline MRI was included from the Clopidogrel in High-risk Patients with Acute Non-disabling Cerebrovascular Events trial.The primary efficacy outcome was the occurrence of an ischaemic stroke at the 1-year follow-up.Infarction numbers were classified as multiple acute infarctions(MAIs),single acute infarction and no acute infarction(NAI).The association between different hs-CRP levels with different infarction numbers and the risk of any outcome was analysed using multivariable Cox regression models.Results Among the 807 patients,84(10.4%)patients had a recurrent ischaemic stroke within 1 year.After adjustment for conventional confounding factors,patients with both elevated hs-CRP levels and MAIs were associated with approximately 4.7-fold of risk of ischaemic stroke within 1 year(16.7% vs 3.5%,HR 4.68,95% CI 1.54 to 14.23,p=0.007),compared with those with non-elevated hs-CRP levels and NAI.Similar results were observed for the composite events.Conclusions Combined elevated hs-CRP levels and MAIs may increase 1-year stroke risk stratification efficiency in patients with minor ischaemic stroke or TIA compared with using those markers alone,which indicated that the combination of inflammatory and imaging markers might improve the effectiveness of risk stratification concerning minor ischaemic stroke or TIA.

Dual antiplatelet therapy may increase the risk of non-intracranial haemorrhage in patients with minor strokes: a subgroup analysis of the CHANCE trial

Aim:The aim of this study was to explore the difference between haemorrhagic events among those patients on either aspirin or aspirin plus clopidogrel who were enrolled in the Clopidogrel in High-Risk Patients with Acute Non-disabling Ischemic Cerebrovascular Events(CHANCE)trial.Methods:This was an ad hoc analysis of the CHANCE trial;data on all patients with any haemorrhagic event were reviewed and analysed.Cox proportional hazards regression was used to determine factors association with any bleeding.Results:In the CHANCE trial,there were a total of 101(2%)haemorrhagic events reported from 50 different hospitals.The clopidogrel–aspirin group had 60(2.3%)cases and the aspirin group had 41(1.6%,p=0.09).Moderate or severe haemorrhagic events occurred in 7 patients(0.3%)in the clopidogrel–aspirin group and in 8(0.3%)in the aspirin group(p=0.73).Of 36(0.7%)cases of intracranial haemorrhages,20(0.4%)were in the clopidogrel–aspirin group and 16(0.3%)in the aspirin group.Each group had 8(0.3%)cases of symptomatic haemorrhagic strokes.Other common haemorrhagic events included 24(0.5%)cases of skin bruises,13(0.3%)gastrointestinal haemorrhages,9(0.2%)gum haemorrhages and 8(0.2%)intraocular haemorrhages.Conclusions:There was no overall significant difference in haemorrhagic events(p=0.29),especially in the rate of intracranial haemorrhages between the 2 treatment groups.However,patients enrolled with minor strokes had an increased risk of haemorrhagic events regardless of treatment group,not seen in patients with high-risk transient ischaemic attacks.Being elderly,of male gender and with a history of aspirin or proton pump inhibitor usage were associated with increased risk of haemorrhage.Patients with higher body mass index had lower risk of haemorrhagic events.