Car-following strategy of intelligent connected vehicle using extended disturbance observer adjusted by reinforcement learning

Disturbance observer-based control method has achieved good results in the carfollowing scenario of intelligent and connected vehicle(ICV).However,the gain of conventional extended disturbance observer(EDO)-based control method is usually set manually rather than adjusted adaptively according to real time traffic conditions,thus declining the car-following performance.To solve this problem,a car-following strategy of ICV using EDO adjusted by reinforcement learning is proposed.Different from the conventional method,the gain of proposed strategy can be adjusted by reinforcement learning to improve its estimation accuracy.Since the“equivalent disturbance”can be compensated by EDO to a great extent,the disturbance rejection ability of the carfollowing method will be improved significantly.Both Lyapunov approach and numerical simulations are carried out to verify the effectiveness of the proposed method.

Degradation of Alkaline Lignin in the Lactic Acid-Choline Chloride System under Mild Conditions

Lignin is a natural polymer,second only to cellulose in natural reserves.Degradation is one of the ways to achieve the high-value transformation of lignin.Deep eutectic solvent(DES)thermal degradation of lignin can be used as an excellent green degradation method.This paper introduces the degradation mechanism and effect of the lactic acid-choline chloride DES system in dissolving and degrading alkaline lignin,and the final solvent recovery.It can also be found from the scanning electron microscope(SEM)images that the surface of the degraded solid product is transformed from smooth to disordered.Fourier transform infrared(FTIR)spectroscopy and 1H-NMR spectroscopy were used to characterize the changes in lignin functional groups during DES treatment.The results showed that the content of phenolic hydroxyl groups increased after degradation,indicating that theβ-O-4 ether bond was broken.The molecular weight of the degraded lignin was observed by gel permeation chromatography(GPC),and the lignin residue with low molecular weight and narrow polydispersity index was obtained.The lowest average molecular weight(Mw)reached 2512 g/mol.The ratio of oxygen to carbon atoms in lignin increased substantially during degradation as measured by X-ray photoelectron spectroscopy(XPS),probably because DES treatment was accompanied by many oxidation reactions,which led to significant structural changes in lignin and a large number of ether bond breakage reactions during the reaction.The main final degradation products are aromatic monomers,vanillin,butyrovanillone,etc.

Investigation of the Interaction Mechanism between Lignin Structural Units and Enzyme

The effect of lignin structural units on enzymatic hydrolysis of lignocellulosic biomass was investigated,especially the inhibitory role of lignin in non-productive adsorption with enzymes.Milled wood lignin(MWL)was isolated from different hardwoods of poplar,eucalyptus and acacia.The isolated lignin samples were characterized by elemental analysis,gel permeation chromatography,nitrobenzene oxidation and fourier infrared spectroscopy.The mechanism of lignin structural units on enzymatic hydrolysis of cellulose was studied by quartz crystal microbalance(QCM).The results showed that different structural units of lignin had different adsorption capacity for enzymes.The results of nitrobenzene oxidation indicated that the S/G ratio(S:syringyl-like lignin structures;G:guaiacyl-like lignin structures)of lignin of poplar was 0.99,that of eucalyptus was 1.92 and that of acacia was 1.34.According to the results of QCM,the adsorption capacity of the three lignin films was as follows:Poplar MWL(S/G ratio 0.99)<Acacia MWL(S/G ratio 1.34)<Eucalyptus MWL(S/G ratio 1.92).Eucalyptus MWL with higher degree of condensation and S/G ratio showed stronger affinity to enzymes and more non-productive adsorption with enzymes,resulting in less adsorption between enzymes and cellulose,and lower enzymatic hydrolysis efficiency.

CsTCPs regulate shoot tip development and catechin biosynthesis in tea plant (Camellia sinensis)

The growth of leaves and biosynthesis of characteristic secondary metabolites are critically important for tea production and quality control.However,little is known about the coordinated regulation of leaf development and catechin biosynthesis in tea plants.Here,we reported that TCP TFs are involved in both catechin biosynthesis and leaf development.An integrated analysis of catechin profiling and CsTCP expression in different tissues of plants under various environmental conditions at different developmental stages indicated significant correlations between the transcript levels of CIN-type TCPs and catechin production.CIN-type CsTCP3 and CsTCP4 and PCF-type CsTCP14 interacted with the MYB-bHLH-WD40 repeat(MBW)complex by forming a CsTCP3-CsTT8 heterodimer and modulating the transactivation activity of the promoters of anthocyanin synthase(CsANSl)and anthocyanidin reductase(CsANRl).Four types of microRNA/target modules,miR319b/CsTCP3-4,miR164b/CsCUC,miR396/CsGRF-GIF,and miR165b/HD-ZIPIII ones,were also identified and characterized for their functions in the regulation of the development of teaplant shoot tips and leaf shape.The results of these modules were reflected by their different expression patterns in developing buds and leaves that had distinctly different morphologies in three different teaplant varieties.Their roles in the regulation of catechin biosynthesis were also further verified by manipulation of microRNA319b(miR319b),which targets the transcripts of CsTCP3 and CsTCP4.Thus,CsTCPs represent at least one of these important groups of TFs that can integrate tea plant leaf development together with secondary metabolite biosynthesis.Our study provides new insight into shoot tip development and catechin production in tea plants and lays a foundation for further mechanistic understanding of the regulation of tea plant leaf development and secondary metabolism.

光催化降解木质素机理与影响因素的研究进展

光催化降解木质素,使大分子木质素降解为小分子增值产品,是一种高效且环保的方法。文中首先综述了光催化降解木质素的作用机理,包括光生空穴(h_(VB)^(+))/电子(e_(CB)^(-)),·OH和O_(2)^(-)·的生成路径以及其各自对木质素β-O-4键断裂的作用机制;其次是反应pH,光催化剂种类、改良和用量,氧化剂种类、用量和与光催化剂组合对光催化降解木质素的影响;最后对光催化降解木质素进行了总结与展望。

封闭聚异氰酸酯对含氟聚丙烯酸酯整理织物性能的影响

制备了不同熔点及解封温度的封闭聚异氰酸酯交联剂(BIC)和含氟聚丙烯酸酯乳液(FPA)。利用红外光谱和透射电镜等对FPA的结构和微观形貌等进行了表征。对添加BIC的FPA乳液(BFPA)浸涂固化整理过的棉织物(BFCM)进行了静态疏水、动态喷淋、接触角、耐摩擦和耐水洗等性能测试,比较了BIC的熔点对BFCM疏水性能的影响。结果表明,随着BIC熔点降低,其解封温度越低,BFCM的防水、耐磨、耐洗等性能均有显著提升。BIC熔点为6.6℃时,其解封温度最低为75℃,经110℃处理后BFCM水接触角(WCA)可达142.9°,沾水等级可达5级;100℃处理后经50个摩擦周期和24 h水洗后,WCA仍然分别可达132.5°和136.5°。

功能化木质素在高分子材料中的应用研究进展

木质素是自然界中含量第二大的天然三维网状的高分子聚合物。以制浆造纸废料或生物质炼制中的工业木质素为原料,制备出具有特殊功能的高附加值材料,实现木质素的高效优化利用,这对解决化石资源日趋紧缺及环境污染等问题具有重要意义。文中首先评价了木质素作为功能性材料的潜在反应特性与应用潜力,介绍了国内外木质素基功能材料的最新研究进展,详细总结了木质素基功能材料在聚氨酯、聚酯、环氧树脂、酚醛树脂、电极储能、碳纤维、纳米粒子以及其他方面的不同制备工艺,评述了木质素微观结构及制备工艺对材料结构特性和应用性能的影响。

长玻纤增强塑料注射成型纤维断裂概述

长玻纤增强塑料(LGFT)能有效改善塑料强度,拓展了塑料的应用范围;但注塑成型中常有纤维断裂的问题而影响玻纤增强效果。文中根据长玻纤增强塑料注射成型的研究成果,从材料、工艺、设备、数学模型和数值模拟方面介绍了注射成型对LGFT制品内玻纤长度的影响,总结了工艺参数及设备结构对纤维断裂的影响,以及纤维断裂模型的进展和数值模拟在纤维长度预测的应用,归纳了LGFT成型加工的适用范围和研究趋势。

基于分子动力学和自由能计算研究小分子对HIF-VHL相互作用的抑制机理

蛋白-蛋白相互作用涉及多种生理过程.其中HIF-VHL作为局部缺血性心脏病的重要靶标得到了学术界和工业界的广泛关注.本文使用分子动力学模拟和结合自由能计算研究pro-like的小分子抑制剂对VHL-HIF的抑制机理.Pro-like抑制剂能够与HIF竞争性地结合在VHL蛋白上,从而破坏VHL-HIF相互作用.基于抑制机理给出了pro-like抑制剂的优化策略.

Characterization of CsWRKY29 and CsWRKY37 transcription factors and their functional roles in cold tolerance of tea plant

The WRKY gene family is most widely known as being the key plant transcription factor family involved in various stress responses and affecting plant growth and development.In this study,a total of 86 members of the CsWRKY genes were identified from the tea plant genome.Most of these genes contain several important Cis-regulatory elements in the promoter regions associated with multiple stress-responses.These genes were further classified into three groups,I,II,and III,each with 21,58,and 7 members,respectively.We showed evidence that tandem duplications,but not the whole genome duplication,are likely to drive the amplification of CsWRKY genes in tea plants.All the 86 CsWRKY genes showed differential expression patterns either in different tissues,or under exposure to diverse abiotic stresses such as drought,cold acclimation,and MeJA treatments.Additionally,the functional roles of two genes,CsWRKY29 and CsWRKY37,were examined under cold stress;and the silencing of these genes resulted in tea plant phenotypes susceptible to cold stress.Moreover,transgenic Arabidopsis lines overexpressing CsWRKY29 and CsWRKY37 genes showed higher survival rates and lower malondialdehyde levels under freezing treatment than the wild type plants.The core findings from this work provide valuable evolutionary pattern of WRKY gene family and underpinning the underlying regulatory roles of CsWRKY29 and CsWRKY37 from tea plants that conferred cold tolerance in transgenic Arabidopsis plants.

Gelatin filter capture-based high-throughput sequencing analysis of microbial diversity in haze particulate matter

Airborne particulate matter(PM),especially PM2.5,can be easily adsorbed by human respiratory system.Their roles in carrying pathogens for spreading epidemic diseases has attracted great concern.Herein,we developed a novel gelatin filter-based and culture-independent method for investigation of the microbial diversity in PM samples during a haze episode in Tianjin,China.This method involves particle capture by gelatin filters,filter dissolution for DNA extraction,and high-throughput sequencing for analysis of the microbial diversity.A total of 584 operational taxonomic units(OTUs)of bacteria and 370 OTUs of fungi at the genus level were identified during hazy days.The results showed that both bacterial and fungal diversities could be evaluated by this method.This study provides a convenient strategy for investigation of microbial biodiversity in haze,facilitating accurate evaluation of airborne epidemic diseases.

Lignocellulose pretreatment by deep eutectic solvents and related technologies:A review

Lignocellulose is the main component of plants and has a wide range of sources.The high-value production of lignocellulose lies in the biorefinery of lignin,cellulose and hemicellulose.The ad-vantages and disadvantages of traditional lignocellulose pretreatment methods were summarized,and the effective pretreatment parameters were listed.As a green solvent system with excellent performance,deep eutectic solvents(DES)are considered to be the most potential biomass pre-treatment system.Based on this,the new trend and progress of DES in lignocellulose pretreatment were reviewed,focusing on the effects of distinct kinds of lignocellulose raw materials,distinct components of DES,distinct reaction conditions and assisted by microwave ultrasound on the pre-treatment of lignocellulose,and the recyclability of DES solution system was discussed.Finally,the application and development direction of DES in lignocellulose pretreatment are proposed and prospected.

Roles of trichomes in tea plant resistance against multiple abiotic and biotic stresses

Tea trichomes contribute significantly to tea flavors by providing diverse and specific flavor-determining metabolites,including catechins,caffeine,theanine,and volatiles.However,not much is known about the physiological functions of tea trichomes in tea plant adaptation to complex environments,nor the trichome development.Tea trichomes not only build up chemical defenses,but also act as the first physical barrier protecting herbivore attacks,reflecting high light and UV-B radiation,and preventing water loss.Moreover,transcriptome profiling on the tea trichomes compared with the trichome-removed leaves also showed that tea trichomes highly expressed numerous defense-related genes involved in protection from high light and UV-B radiation,cold stress,disease resistance signal transduction,anti-herbivore or anti-abiotic peptide biosynthesis,and other defense responses.Several pieces of experimental evidence supported the notes,highlighting the roles of tea trichomes in plant defenses against both abiotic and biotic stresses.The study provides fresh insights into the multiple protective functions of tea trichome for tea plant adaptation to harsh environments.The new understanding on tea trichomes could benefit the development of better breading strategy for new tea varieties with greater adaption and tolerance to changing environmental challenges.

隔离病房内呼吸道传染性疾病气溶胶吸入感染风险

医疗机构的院内感染给患者、医护人员和国家造成了巨大的健康和社会经济损失.气溶胶可以携带多种致病微生物,是院内感染的重要传播途径.量化确定医疗机构内的病原微生物浓度与感染风险对于减少院感发生和应对新发突发传染病具有重要意义.本研究以新型冠状病毒(severe acute respiratory syndrome coronavirus 2,SARSCoV-2)为例,针对医院隔离病房,将计算流体动力学(computational fluid dynamics,CFD)与定量微生物风险评估(quantitative microbial risk assessment,QMRA)相结合,建立了气溶胶传播感染风险定量评估模型.基于该模型,计算了隔离病房空气中的病毒浓度,定量评估了医护人员的吸入感染风险,分析了活动强度、个人防护、病毒变异、感染者个体差异等因素对感染风险的影响.结果表明,病房内的感染风险分布具有明显的空间异质性;吸入感染风险与个人活动强度和防护情况密切相关,高活动强度下的感染风险能达到中等活动强度的2倍左右;使用N95口罩可明显降低医护人员的吸入感染风险,无防护状态下的吸入感染风险是使用N95口罩时的3~10倍;毒株变异和个体差异会对感染风险产生明显影响,应该密切关注并及时调整防控策略.研究结果可以为医疗机构的感染防控提供理论依据和技术支持.

Occurrence, polarity and bioavailability of dissolved organic matter in the Huangpu River,China

Dissolved organic matter(DOM)plays an important role in biogeochemical cycles in aquatic ecosystem.To investigate the characteristics of DOM in Huangpu River(the last tributary of the Yangtze River),surface water samples were collected along the river from December2011 to June,2013.The concentrations of dissolved organic carbon(DOC),the absorbance and fluorescence spectrum of DOM in water samples were measured.Fluorescent DOM in the Huangpu River was decomposed into four components by the parallel factor analysis(PARAFAC),including one humic-like substance and three protein-like substances.It showed that high spatial variability of DOC concentration was observed in the upstream water compared to the downstream water,and so did the absorbance coefficients of chromophoric dissolved organic matter and the total fluorescence intensities of different PARAFAC components of DOM.Furthermore,there was a large difference between the polarity and bioavailability of DOM in the Huangpu River.Polar compounds dominated tyrosine-like component of fluorescent DOM in all seasons.Tryptophan-like and humic-like substances had more polar fraction in summer and autumn than those in winter,while aromatic protein-like materials had the highest polar fraction in winter.Almost all of fluorescent DOM components were refractory in spring,while less than 20%of fluorescent DOM in average were biodegradable within 4 weeks in other seasons.We concluded that the spatial variation in the abundance of DOM in the Huangpu River is mainly affected by the water discharges from the Hangjiahu Plain and the seasonal difference in polarity and bioavailability of DOM is largely determined by its origins.

Recovery of a Far-Eastern Strain of Tick-Borne Encephalitis Virus with a Full-Length Infectious cDNA Clone

Tick-borne encephalitis virus(TBEV) is a pathogenic virus known to cause central nervous system(CNS) diseases in humans, and has become an increasing public health threat nowadays. The rates of TBEV infection in the endemic countries are increasing. However, there is no effective antiviral against the disease. This underscores the urgent need for tools to study the emergence and pathogenesis of TBEV and to accelerate the development of vaccines and antivirals. In this study, we reported an infectious c DNA clone of TBEV that was isolated in China(the WH2012 strain). A beta-globin intron was inserted in the coding region of nonstructural protein 1(NS1) gene to improve the stability of viral genome in bacteria. In mammalian cells, the inserted intron was excised and spliced precisely, which did not lead to the generation of inserted mutants. High titers of infectious progeny viruses were generated after the transfection of the infectious clone. The cDNA-derived TBEV replicated efficiently, and caused typical cytopathic effect(CPE) and plaques in BHK-21 cells. In addition, the CPE and growth curve of cDNA-derived virus were similar to that of its parental isolate in cells. Together, we have constructed the first infectious TBEV cDNA clone in China, and the clone can be used to investigate the genetic determinants of TBEV virulence and disease pathogenesis, and to develop countermeasures against the virus.

Silicon Carbide Supported Palladium-Iridium Bimetallic Catalysts for Efficient Selective Hydrogenation of Cinnamaldehyde

Summary of main observation and conclusion Selective hydrogenation of a,B-unsaturated carbonyls into saturated carbonyls is important to obtain remunerative products.However,it is still a challenge to achieve high activity and selec tivity under mild conditions.Herein,Pd,Ir and bimetallic Pd-Ir nanoparticles were uniformly deposited with high dispersity on the surface of SIC by a facile impregnation method,respectively.The as prepared Pd/SIC catalysts eficiently hydrogenate cinnamaldehyde to hydrocinnamaldehyde at room temperature and atmospheric pressure,and the activity of Pd/SiC is observed further enhanced by adding Ir component(conversion of 100%).In addition,the dependence of Pd-lr catalyst activity on Pd/Ir molar ratio con.firms a synergistic effect between Ir and Pd,which originates from the electron transfer between Pd and Ir.

Hard nanocrystalline gold materials prepared via high-pressure phase transformation

As one of the important materials,nanocrystalline Au(n-Au)has gained numerous interests in recent decades owing to its unique properties and promising applications.However,most of the current n-Au thin films are supported on substrates,limiting the study on their mechanical properties and applications.Therefore,it is urgently desired to develop a new strategy to prepare nAu materials with superior mechanical strength and hardness.Here,a hard n-Au material with an average grain size of~40 nm is prepared by cold-forging of the unique Au nanoribbons(NRBs)with unconventional 4H phase under high pressure.Systematic characterizations reveal the phase transformation from 4H to face-centered cubic(fcc)phase during the cold compression.Impressively,the compressive yield strength and Vickers hardness(HV)of the prepared n-Au material reach~140.2 MPa and~1.0 GPa,which are 4.2 and 2.2 times of the microcrystalline Au foil,respectively.This work demonstrates that the combination of high-pressure cold-forging and the in-situ 4H-to-fcc phase transformation can effectively inhibit the grain growth in the obtained n-Au materials,leading to the formation of novel hard n-Au materials.Our strategy opens up a new avenue for the preparation of nanocrystalline metals with superior mechanical property.

Atomistic understanding of interfacial processing mechanism of silicon in water environment:A ReaxFF molecular dynamics simulation

The interfacial wear between silicon and amorphous silica in water environment is critical in numerous applications.However,the understanding regarding the micro dynamic process is still unclear due to the limitations of apparatus.Herein,reactive force field simulations are utilized to study the interfacial process between silicon and amorphous silica in water environment,exploring the removal and damage mechanism caused by pressure,velocity,and humidity.Moreover,the reasons for high removal rate under high pressure and high velocity are elucidated from an atomic perspective.Simulation results show that the substrate is highly passivated under high humidity,and the passivation layer could alleviate the contact between the abrasive and the substrate,thus reducing the damage and wear.In addition to more Si-O-Si bridge bonds formed between the abrasive and the substrate,new removal pathways such as multibridge bonds and chain removal appear under high pressure,which cause higher removal rate and severer damage.At a higher velocity,the abrasive can induce extended tribochemical reactions and form more interfacial Si-O-Si bridge bonds,hence increasing removal rate.These results reveal the internal cause of the discrepancy in damage and removal rate under different conditions from an atomic level.

Metabolomics of ginger based on ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry technology

Objectives:Dried ginger and ginger are the same type of medicine and food.The differential components of ginger and dried ginger,dried ginger and ginger charcoal were investigated.Materials and Methods:The experimental materials were divided into three sample groups:the ginger group,dried ginger group,and ginger charcoal group.The ginger group,dried ginger group,and ginger charcoal group were qualitatively analyzed by ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry.The data were processed by Marker View Software.Principal component analysis and orthogonal partial least-square discriminant analysis were performed with SIMCA 13.0 Software.The differential components of the ginger and dried ginger groups as well as the dried ginger and ginger charcoal groups with a variable importance in the projection>2(P<0.05)were identified with PeakView 1.2 Software.Results:Ten differential components,including 6-gingerol,8-gingerol,and 10-gingerol,were identified between the ginger group and dried ginger group;13 differential components,including 6-shogaol,10-gingerol,and zingiberone,were identified between the dried ginger group and ginger charcoal group.Conclusions:The main differential components between the ginger and dried ginger groups and the dried ginger and ginger charcoal groups were gingerols and diphenylheptanes.Based on metabolomics analysis of the chemical composition of ginger’s medicinal materials,effects,and other related factors,it is recommended that 6-gingerol,6-shogaol,and zingiberone should be used as indicative components for the respective quality evaluation of ginger,dried ginger and ginger charcoal.The results of this study may provide a basis for the reasonable quality evaluation of ginger medicinal materials.