一种双层多糖水凝胶用于增强益生菌肠道靶向口服递送

Transplantation of probiotics to the intestine can positively regulate the gut microbiota,thereby promoting the immune system and treating various diseases.However,the harsh gastrointestinal environment and short retention time in the gastrointestinal tract significantly limit the bioavailability and intestinal colonization of probiotics.Herein,we present a double-layer polysaccharide hydrogel(DPH)in the form of a double-layer structure composed of a carboxymethyl cellulose(CMCL)supramolecular inner layer and a dialdehyde alginate(DAA)cross-linked carboxymethyl chitosan(CMCS)outer layer.This doublelayer structure allows DPH to encapsulate and deliver probiotics in a targeted manner within the body.In the stomach,the cage structure of the DPH is closed,and the outer layer absorbs surrounding liquids to form a barrier to protect the probiotics from gastric fluids.In the intestine,the cage structure opens and disintegrates,releasing the probiotics.Thus,DPH endows probiotics with excellent intestine-targeted delivery,improved oral bioavailability,enhanced gastrointestinal tract tolerance,and robust mucoadhesion capacity.The encapsulated probiotics exhibit almost unchanged bioactivity in the gastrointestinal tract before release,as well as improved oral delivery.In particular,probiotics encapsulated by DPH exhibit 100.1 times higher bioavailability and 10.6 times higher mucoadhesion than free probiotics in an animal model 48 h post-treatment.In addition,with a remarkable ability to survive and be retained in the intestine,probiotics encapsulated by DPH show excellent in vitro and in vivo competition with pathogens.Notably,DAA-mediated dynamic crosslinking not only maintains the overall integrity of the hydrogels but also controls the release timing of the probiotics.Thus,it is expected that encapsulated substances(probiotics,proteins,etc.)can be delivered to specific sites of the intestinal tract by means of DPH,by controlling the dynamic covalent crosslinking.

Bidirectional rectifier with gate voltage control based on Bi_(2)O_(2)Se/WSe_(2)heterojunction

Two-dimensional(2D)WSe_(2)has received increasing attention due to its unique optical properties and bipolar behavior.Several WSe_(2)-based heterojunctions exhibit bidirectional rectification characteristics,but most devices have a lower rectification ratio.In this work,the Bi_(2)O_(2)Se/WSe_(2)heterojunction prepared by us has a typeⅡband alignment,which can vastly suppress the channel current through the interface barrier so that the Bi_(2)O_(2)Se/WSe_(2)heterojunction device has a large rectification ratio of about 10^(5).Meanwhile,under different gate voltage modulation,the current on/off ratio of the device changes by nearly five orders of magnitude,and the maximum current on/off ratio is expected to be achieved 106.The photocurrent measurement reveals the behavior of recombination and space charge confinement,further verifying the bidirectional rectification behavior of heterojunctions,and it also exhibits excellent performance in light response.In the future,Bi_(2)O_(2)Se/WSe_(2)heterojunction field-effect transistors have great potential to reduce the volume of integrated circuits as a bidirectional controlled switching device.

An Improved JSO and Its Application in Spreader Optimization of Large Span Corridor Bridge

In this paper,given the shortcomings of jellyfish search algorithmwith low search ability in the early stage and easy to fall into local optimal solution,this paper introduces adaptive weight function and elite strategy,improving the global search scope in the early stage and the ability to refine the local development in the later stage.In the numerical study,the benchmark problem of dimensional optimization with a 10-bar truss structure and simultaneous dimensional shape optimization with a 15-bar truss structure is adopted,and the corresponding penalty method is used for constraint treatment.The test results show that the improved jellyfish search algorithm can provide better truss sections as well as weights.Because when the steel main truss of the large-span covered bridge is lifted,the site is limited and the large lifting equipment cannot enter the site,and the original structure does not meet the problem of stress concentration and large deformation of the bolt group,so the spreader is used to lift,and the improved jellyfish search algorithm is introduced into the design optimization of the spreader.The results show that the improved jellyfish algorithm can efficiently and accurately find out the optimal shape and weight of the spreader,and throughMidas Civil simulation,the spreader used canmeet the requirements of weight and safety.

以核酸适体为载体讨论前沿技术和应用成果在分析化学教学中的作用

核酸适体是一类特殊的寡核苷酸序列,由于其对目标物表现出优异的亲和性和选择性,在分子医学等领域得到了广泛应用。核酸适体作为重要前沿技术和应用成果,对其进行深入学习和研究,将对培养高素质人才、推动社会发展有着重要影响。在分析化学教学中以核酸适体为载体讨论前沿技术和应用成果对于满足国家和社会需求、培育学生家国意识和社会责任感、提升精神境界等方面有着重要作用,是分析化学教学改革的一项必要手段。本文针对核酸适体相关前沿学术和应用成果在化学教学中的重要思想教育作用进行了简要讨论。

Variation in glomalin in soil profiles and its association with climatic conditions,shelterbelt characteristics,and soil properties in poplar shelterbelts of Northeast China

Glomalin-related soil protein(GRSP)sequesters large amounts of carbon and plays important roles in maintaining terrestrial soil ecosystem functions and ecological restoration;however,little is known about GRSP variation in 1-m soil profiles and its association with stand characteristics,soil properties,and climatic conditions,hindering GRSP-related degraded soil improvement and GRSP evaluation.In this study,we sampled soils from 1-m profiles from poplar(Populus spp.)shelterbelts in Northeast China.GRSP contents were 1.8–2.0 times higher in the upper 40 cm soil layers than at 40–100 cm.GRSP-related soil organic carbon(SOC)sequestration in deeper soil layers was*1.2 times higher than in surface layers.The amounts of GRSP-related nutrients were similar throughout the soil profile.A redundancy analysis showed that in both surface and deeper layers,soil properties(pH,electrical conductivity,water,SOC,and soil nutrients)explained the majority of the GRSP variation(59.5–84.2%);the second-most-important factor in GRSP regulation was climatic conditions(temperature,precipitation,and altitude),while specific shelterbelt characteristics had negligible effects(<5%).Soil depth and climate indirectly affected GRSP features via soil properties,as manifested by structural equation model analysis.Our findings demonstrate that GRSP is important for carbon storage in deep soils,regardless of shelterbelt characteristics.Future glomalin assessments should consider these vertical patterns and possible regulating mechanisms that are related to soil properties and climatic changes.

Tolerance to low phosphorus in rice varieties is conferred by regulation of root growth

Phosphorus use efficiency(PUE)can be improved through cultivation techniques and breeding.However,little is known about rice(Oryza sativa L.)agronomic and physiological traits associated with high PUE.We characterized the agronomic and physiological traits of rice varieties with different tolerances to low phosphorus in nutrient solution.Two varieties with strong tolerance to low phosphorus(STVs)and two with weak tolerance(WTVs)were grown at normal(NP,control)and low phosphorus(LP,1/20 of NP)concentrations.Plants grown at LP produced significantly lower grain yield than those grown at NP.WTVs yields were lower than STVs yields.Compared to NP,LP significantly increased phosphorus translocation efficiency(PTE),internal phosphorus efficiency(IPE)and phosphorus harvest index(PHI).Under the LP condition,PTE and IPE were higher for STVs than for WTVs.LP also reduced tiller number,shoot biomass,leaf area index(LAI),leaf photosynthetic rate,and mean root diameter of both kinds of varieties at the main growth stages,but to a lower extent in STVs.LP significantly increased the number of productive tillers,root biomass,root-shoot ratio,root bleeding rate,and root acid phosphatase(RAP)activity.Total root length,root oxidation activity(ROA),and root total and active absorbing surface areas for STVs were significantly increased under LP,whereas the opposite responses were observed for WTVs.Total root length,ROA,root bleeding rate,root active absorbing surface area,and RAP activity were positively and significantly correlated with grain yield,PTE,and IPE.These results suggest that the tolerance of rice varieties to a low-phosphorus growth condition is closely associated with root growth with higher biomass and activity.

High performance and stability of double perovskite-type oxide NdBa0.5Ca0.5Co1.5Fe0.5O5+δas an oxygen electrode for reversible solid oxide electrochemical cell

In this study,we successfully synthesized double perovskite-type oxide NdBa0.5Ca0.5Co1.5Fe0.5O5+δ(NBCCF)using a conventional wet chemical method as the oxygen electrode for reversible solid oxide electrochemical cells(RSOCs).The polarization resistance(Rp)of the composite electrode NBCCFGd0.1Ce0.9O2(GDC)is only 0.079Ωcm^2 at 800℃under air.The single cell based on NBCCF-GDC electrode displays a peak power density of 0.941 W/cm^2 in fuel cell mode and a low Rp value of 0.134Ωcm^2.In electrolysis cell mode,the cell displays an outstanding oxygen evolution reaction(OER)activity and shows current density as high as 0.92 A/cm^2 with 50 vol%AH(Absolute Humidity)at 800℃and applied voltage of 1.3 V.Most importantly,the cell exhibits admirable durability of 60 h both in electrolysis mode and fuel cell mode with distinguished reversibility.All these results suggest that NBCCF is a promising candidate electrode for RSOC.

Forest plant and macrofungal differences in the Greater and Lesser Khingan Mountains in Northeast China:A regional-historical comparison and its implications

Forests in Northeast China in the Greater and Lesser Khingan Mountains(GKM and LKM)account for nearly 1/3 of the total state-owned forests in the country.Regional and historical comparisons of forest plants and macrofungi will favor biological conservation,forest management and economic development.A total of 1067 sampling plots were surveyed on forest composition and structure,with a macrofungi survey at Liangshui and Huzhong Nature Reserves in the center of two regions.Regional and historical differences of these parameters were analyzed with a redundancy ordination of their complex associations.There were 61-76 families,189-196 genera,and 369-384 species,which was only 1/3 of the historical records.The same dominant species were larch and birch with Korean pine(a climax species)less as expected from past surveys in the LKM.Shrub and herb species were different in the two regions,as expected from historical records.There was 10-50%lower species diversity(except for herb evenness),but 1.8-to 4-time higher macrofungi diversity in the GKM.Compared with the LKM,both tree heights and macrofungi density were higher.Nevertheless,current heights averaging 10 m are half of historical records(>20 m in the 1960s).Edible macrofungi were the highest proportion in both regions,about twice that of other fungal groups,hav-ing important roles in the local economy.A major factor explaining plant diversity variations in both regions was herb cover,followed by shrubs in the GKM and herb-dominant species in the LKM.Factors responsible for macrofungi variations were tree density and shrub height.Vaccinium vitis-idaea and Larix gmelinii in the GKM but tree size and diversity were important factors in the LKM.Our findings highlighted large spatial and historical differences between the GKM and LKM in plant-macrofungal composition,forest structure,and their complex associations,which will favor precise conservation and management of forest resources in two region in the future.

Aerodynamic-Parameter Identification and Attitude Control of Quad-Rotor Model with CIFER and Adaptive LADRC

Current research on quadrotor modeling mainly focuses on theoretical analysis methods and experimental methods,which have problems such as weak adaptability to the environment,high test costs,and long durations.Additionally,the PID controller,which is currently widely used in quadrotors,requires improvement in anti-interference.Therefore,the aforementioned research has considerable practical significance for the modeling and controller design of quadrotors with strong coupling and nonlinear characteristics.In the present research,an aerodynamic-parameter estimation method and an adaptive attitude control method based on the linear active disturbance rejection controller(LADRC)are designed separately.First,the motion model,dynamics model,and control allocation model of the quad-rotor are established according to the aerodynamic theory and Newton-Euler equations.Next,a more accurate attitude model of the quad-rotor is obtained by using a tool called CIFER to identify the aerodynamic parameters with large uncertainties in the frequency domain.Then,an adaptive attitude decoupling controller based on the LADRC is designed to solve the problem of the poor anti-interference ability of the quad-rotor and adjust the key control parameter b0 automatically according to the change in the moment of inertia in real time.Finally,the proposed approach is verified on a semi-physical simulation platform,and it increases the tracking speed and accuracy of the controller,as well as the anti-disturbance performance and robustness of the control system.This paper proposes an effective aerodynamic-parameter identification method using CIFER and an adaptive attitude decoupling controller with a sufficient anti-interference ability.

Discrete Optimization on Unsteady Pressure Fluctuation of a Centrifugal Pump Using ANN and Modified GA

Pressure fluctuation due to rotor-stator interaction in turbomachinery is unavoidable,inducing strong vibration in the equipment and shortening its lifecycle.The investigation of optimization methods for an industrial centrifugal pump was carried out to reduce the intensity of pressure fluctuation to extend the lifecycle of these devices.Considering the time-consuming transient simulation of unsteady pressure,a novel optimization strategy was proposed by discretizing design variables and genetic algorithm.Four highly related design parameters were chosen,and 40 transient sample cases were generated and simulated using an automatic program.70%of them were used for training the surrogate model,and the others were for verifying the accuracy of the surrogate model.Furthermore,a modified discrete genetic algorithm(MDGA)was proposed to reduce the optimization cost owing to transient numerical simulation.For the benchmark test,the proposed MDGA showed a great advantage over the original genetic algorithm regarding searching speed and effectively dealt with the discrete variables by dramatically increasing the convergence rate.After optimization,the performance and stability of the inline pump were improved.The efficiency increased by more than 2.2%,and the pressure fluctuation intensity decreased by more than 20%under design condition.This research proposed an optimization method for reducing discrete transient characteristics in centrifugal pumps.

低泡表面活性剂AMEO的合成及性能研究

以壬二酸二单乙醇酰胺为原料,通过乙氧基化反应合成了一系列具有不同氧乙烯含量的壬二酸二单乙醇酰胺聚氧乙烯醚(AMEO-p,p=30,40,50,60,70)低泡型表面活性剂。通过红外谱图证明合成了目标产物,并测定了实际氧乙烯含量,其结果与理论氧乙烯含量基本一致。测试了系列AMEO-p的润湿性,去污性,泡沫性等应用性能,优选出润湿性能好,去污力强,泡沫低的AMEO-50表面活性剂。并对其表面性质与物化性能进行了系统研究。结果表明,AMEO-50的临界胶束浓度为0.5 g/L,平衡表面张力为31.21 mN/m。其质量浓度的增加会导致动态表面张力达到平衡的时间缩短,且表面张力降低的速率增快。另外AMEO-50可以与水任意比例互溶,无凝胶相区,具有高浊点,低凝固点的特性,是一种应用温度范围广、可用于超浓缩洗涤产品配方中的低泡型表面活性剂。

Ca2+依赖的膜结合蛋白7在胃癌中的表达及临床意义

目的:探讨Ca2+依赖的膜结合蛋7(CPNE7)在胃癌中的表达水平及其与肿瘤发生发展的关系。方法:首先通过生物信息学分析CPNE7在胃癌及癌旁中的表达差异及其与预后的关系。收集2020年1月至2021年5月在兰州大学附属第二医院行手术治疗的102例胃癌患者的癌组织及其癌旁组织,制作成组织芯片(TMA),采用免疫组织化学染色法检测CPNE7的表达水平,Spearman相关分析CPNE7表达与胃癌患者临床病理特征的关系。采用RT-PCR和Western blot检测CPNE7在胃癌细胞(MKN45/AGS/HGC-27)和人正常胃黏膜细胞(GES-1)中mRNA和蛋白的表达水平。结果:CPNE7蛋白及其mRNA水平在胃癌中高于癌旁组织(P<0.05),CPNE7的表达与患者的临床分期(P<0.001)、T分期(P=0.012)、N分期(P=0.01)以及有无淋巴结浸润(P=0.005)和Lauren’s分型(P=0.007)显著相关,与年龄(P=0.37)、性别(P=0.121)、分化程度(P=0.15)、有无转移(P=0.835)、血管浸润(P=0.275)、神经浸润无相关(P=0.814)。结论:CPNE7在胃癌组织和细胞中呈高表达,其表达与临床分期、T分期、N分期、淋巴结浸润和Lauren’s分型相关,提示CPNE7可能参与胃癌的发生发展,有望成为胃癌的诊断标志物。

用于预测癌症患者临床治疗方案的小鼠mini人源肿瘤异种移植模型的建立

背景与目的患者来源的类器官(patient-derived organoids,PDOs)和异种移植物(patientderivedxenografts,PDXs)具有较强的预测抗癌药物药效的能力,是功能检测的重要模型。然而,移植失败、构建PDX模型和随后检测药效的耗时过长、体外器官培养无法进行系统性给药等限制因素严重阻碍了其在临床上的应用,无法快速地筛选正确、可行的治疗方案。本研究旨在开发一种名为'miniPDX'的改良的PDX模型,用于快速检测药效,提高其在个体化癌症治疗中的应用价值。方法我们开发了一种快速检测体内药物敏感性的方法——OncoVee?MiniPDX,用于筛选癌症临床治疗方案。本模型将患者来源的肿瘤细胞注入中空纤维胶囊内,皮下植入小鼠体内培养7 d。系统评价了细胞的活性形态和药代动力学。以PDX为对照评估miniPDX的性能(敏感性、特异性、阳性和阴性预测值)。分别采用PDX和miniPDX模型以肿瘤生长抑制率和肿瘤细胞生长抑制率为指标检测药物反应。评价miniPDX模型对临床疗效的预测能力。结果MiniPDX胶囊内肿瘤细胞的形态学和组织病理学特征与PDX模型和原发肿瘤细胞的形态学和组织病理学特征均保持一致。26例(包括14例胃癌、10例肺癌和2例胰腺癌)来自患者的PDX肿瘤移植试验的药物反应与相应的miniPDX试验的药物反应结果具有良好的相关性。MiniPDX阳性预测值为92%,阴性预测值为81%,敏感性为80%,特异性为93%。通过扩大临床肿瘤样本,miniPDX检测显示出广泛的临床应用潜力。结论我们建立了基于胶囊植入技术的miniPDX快速体内检测方法,用于评估PDX肿瘤移植物和临床肿瘤标本的药物反应。PDX模型和其对应的miniPDX药效结果具有良好的相关性,结合转化研究数据最终表明miniPDX模型是一种先进的个体化癌症治疗工具。

Improved STCA Model for Multi-Lane Using Driving Guidance under CVIS

In a multi-lane area,the increasing randomness of lane changes contributes to traffic insecurity and local traffic flow instability.A study on safe lane shifting activity that focuses on threat assessment under real-time knowledge is necessary to enhance smooth vehicle flow.This paper proposed amore comprehensive lane changing guidance rule to investigate the status of surrounding vehicles to accommodate future vehicle-on-road collaborative environments based on these parameters 1)lane change demand and 2)treat assessment function.The collaborative relationships between vehicles are analyzed using a cellular automata model based on their location,velocity,and acceleration.We analyze and examine the relationship between the number of lanes and traffic flow when the road capacity is heavily mined via intelligent lane changing.Our analysis can further provide theoretical guidance for the selection of road expansion mode.Our proposed STCA-L is compared based on the average speed,average flow,lane changing frequency,spatial and temporal pattern of STCA,STCA-I,and STCA-S,and STCA-M under different vehicle densities.The numerical simulation results show that our proposed STCA-L provides themost flexible lane changing guidance in the multi-lanes road.Moreover,the simulated results show that the exponential growth of physical space cannot provide the corresponding increase in the average flow of vehicles.

SHFuzz:A Hybrid Fuzzing Method Assisted by Static Analysis for Binary Programs

Fuzzing is an effective technique to find security bugs in programs by quickly exploring the input space of programs.To further discover vulnerabilities hidden in deep execution paths,the hybrid fuzzing combines fuzzing and concolic execution for going through complex branch conditions.In general,we observe that the execution path which comes across more and complex basic blocks may have a higher chance of containing a security bug.Based on this observation,we propose a hybrid fuzzing method assisted by static analysis for binary programs.The basic idea of our method is to prioritize seed inputs according to the complexity of their associated execution paths.For this purpose,we utilize static analysis to evaluate the complexity of each basic block and employ the hardware trace mechanism to dynamically extract the execution path for calculating the seed inputs’weights.The key advantage of our method is that our system can test binary programs efficiently by using the hardware trace and hybrid fuzzing.To evaluate the effectiveness of our method,we design and implement a prototype system,namely SHFuzz.The evaluation results show SHFuzz discovers more unique crashes on several real-world applications and the LAVA-M dataset when compared to the previous solutions.

Efficacy and Safety of Triazavirin Therapy for Coronavirus Disease 2019:A Pilot Randomized Controlled Trial

目前,尚无有效疗法可治愈由严重急性呼吸综合征冠状病毒2(severe acute respiratory syndrome coronavirus 2,SARS-CoV-2)引起的新型冠状病毒肺炎(coronavirus disease 2019,COVID-19)。为了评估抗病毒药物特力阿扎维林治疗COVID-19的有效性和安全性,本研究针对感染COVID-19的成年住院患者开展了一项随机双盲对照试验。本研究从10个分中心招募COVID-19患者,并将患者按1:1的比例随机分为两组。试验组的患者每天服用250 mg的特力阿扎维林药物3~4次,对照组患者则服用安慰剂,为期共7 d。主要结局指标为临床改善时间,临床改善时间的定义为随机分组28d内患者的体温、呼吸频率、血氧饱和度、咳嗽频率和肺CT(计算机断层扫描,computed tomography)所显示的肺部感染吸收情况全部恢复正常的时间。次要结局指标包括主要结局指标的5个组成指标,及肺部感染吸收的平均时间和吸收比例,以及用咽拭子采样法连续两次SARS-CoV-2核酸检测阴性的转阴率。与此同时,记录合并的治疗药物、不良事件和严重不良事件。由于需要进行住院治疗的新增感染病例的减少,本研究在招募52名患者后便停止招募。将52名受试者随机分为服用特力阿扎维林药物的试验组(n=26)和服用安慰剂的对照组(n=26)。结果显示,两组临床改善时间并无明显差异[中位数,7 d vs.12 d;风险比(RR)为2.0;95%置信区间(CI)为0.7~5.6;p=0.2]。服用特力阿扎维林的试验组中有10名患者发生临床改善,服用安慰剂的对照组中有6名患者出现临床改善(38.5%vs.23.1%,RR为2.1;95%CI为0.6~7.0;p=0.2)。除了肺部感染的吸收情况外(试验组50.0%,对照组26.1%),其余主要结局所观察指标均在28 d内恢复正常。此外,试验组的患者在呼吸系统、心脏、肾、肝或凝血功能等方面的合并治疗较对照组少。尽管特力阿扎维林药物对COVID-19患者的疗效尚未达到统计学上的显著性水平,但本研究结果表明,由于特力阿扎维林药物具有抗病毒作用,将其用于COVID-19的治疗也可能具有一定的疗效。对此,需要进一步的研究进行验证。

Response Surface Optimization of Ultrasound-assisted Aqueous Two-phase Extraction of Sweet Potato Leaf Polysaccharides

[Objectives]The ultrasound-assisted aqueous two-phase extraction of sweet potato leaf polysaccharides was studied.[Methods]With the yield of sweet potato leaf polysaccharides as the index,the aqueous two-phase extraction system was determined,and the optimal extraction conditions were optimized by single-factor experiments and response surface methodology.[Results]The optimal parameters were ethanol concentration 25.68%,liquid-to-material ratio 55.83,and ultrasonic treatment time 38.33 min.Under these conditions,the yield of sweet potato leaf polysaccharides could reach 20.646 mg/g.[Conclusions]The ethanol/ammonium sulfate aqueous system is a rapid and efficient method for extracting sweet potato leaf polysaccharides,which is of great significance for the application of sweet potato leaf extract as a natural food additive.

An Empirical Study of Characteristics of the Spatial Distribution of Taobao Travel Intemet Store

The development of tourism depends on the development of physical stores and the level of economic development of tourism, distribution, and analysis of the main research shop this virtual store. In this study, based on China＇s largest e-commerce website --- Taobao C2C data to the country＇s 31 provinces, autonomous regions and municipalities （excluding Hung Kong, Macao and Taiwan） for the study, and regression analysis using ArcGIS software tools, from the provincial tourism C2C e-commerce Factors affecting the development of conduct Regression analysis, and An Empirical Study of the geographical distribution of the electrons. The results showed that the development of China＇s tourism e-commerce C2C level and the level of tourism development and local economic development are very relevant. The degree of economic development and the level of development of tourism and travel Taobao C2C e number of shops are highly correlated.

Poisoning effect of polyvinyl chloride on the catalytic pyrolysis of mixed plastics over zeolites

Nowadays,the chemical recycling is applied for only 1%of total waste plastics,largely due to contaminants in plastic waste and difficulty in product control.As the major contaminant,polyvinyl chloride(PVC)often forms corrosive hydrogen chloride(HCl)during the chemical recycling,which may cause severe catalyst deactivation and equipment damage.However,the investigation on catalytic pyrolysis(the major route for plastics chemical recycling)of the PVC containing mixed plastics has been rarely reported.Here,catalytic co-pyrolysis of PVC and polyethylene(PE)was studied over an aromatization catalyst,Pt/ZSM-5,since the basic building block aromatics are desired products from plastics chemical recycling.The poisoning effect of PVC vapor on the catalyst stability was explored by collective efforts of thorough product analysis and catalyst characterization.It was found that the HCl evolving from PVC has an autocatalytic effect that promotes the scission of dehydrochlorinated PVC,resulting in the high yield of benzene and acetylene from PVC.On the other hand,the presence of PVC suppressed the aromatics formation from PE,largely due to the poisoning effect of PVC-derived HCl on the Pt/ZSM-5.The deactivation is irreversible as evidenced by the decreased zeolite crystallinity and the loss of strong acid sites that are key to the aromatization,possibly due to the removal of framework Al upon the interaction with HCl.The modification with octadecylphosphonic acid only slightly alleviated the PVC poisoning effect.The insights on the PVC poisoning of zeolite catalysts provided in this work may guide the process design of chemical recycling of PVC containing waste plastics.

富Fe^(2+)层状材料FeOCl的低热导率

层状无机材料的弱层间耦合和大面积表面为构建低导热性无机固体材料提供了基本框架.合成具有足够散射和非谐波性的稳定层状材料,从而降低热导率,仍是一项挑战.本文在层状无机FeOCl材料体系中,通过一步氧化还原反应成功获得了一种结构稳定的富含Fe^(2+)的层状材料,实现了表面和界面的同步改性,并实现了超低的热导率.具体而言,系统的X射线吸收精细结构(XAFS)分析和电子能量损失光谱(EELS)分析表明,碱金属原子的层间插层和表面缺陷的引入诱导了大量Fe^(2+)的存在,从而增强了其非谐波性和声子散射.此外,声子态密度(PDOS)分布也提供了确凿的证据,证明了散射概率的提高和声子模式整体的软化.所制得的层状无机材料Fe(III)_(1−n)Fe(II)_(n)O_(1−x)Cl[K^(+)]_(m)不仅结构稳定,而且在298 K时的热导率比原始FeOCl降低了近60%,低至0.29 W m^(−1) K^(−1),这在层状无机材料中是极低的.这项研究为低导热层状材料的设计提供了新的视角.