Amino-functionalized UiO-66-doped mixed matrix membranes with high permeation performance and fouling resistance

For the reduction of bovine serum proteins from wastewater,a novel mixed matrix membrane was prepared by functionalizing the substrate material polyaryletherketone(PAEK),followed by carboxyl groups(C-SPAEKS),and then adding amino-functionalized UiO-66-NH_(2)(Am-UiO-66-NH_(2)).Aminofunctionalization of UiO-66 was accomplished by melamine,followed by an amidation reaction to immobilize Am-UiO-66-NH_(2),which was immobilized on the surface of the membrane as well as in the pore channels,which enhanced the hydrophilicity of the membrane surface while increasing the negative potential of the membrane surface.This nanoparticle-loaded ultrafiltration membrane has good permeation performance,with a pure water flux of up to 482.3 L·m^(-2)·h^(-1) for C-SPAEKS/AmUiO-66-NH_(2) and a retention rate of up to 98.7%for bovine serum albumin(BSA)-contaminated solutions.Meanwhile,after several hydrophilic modifications,the flux recovery of BSA contaminants by this series of membranes increased from 56.2%to 80.55%of pure membranes.The results of ultra-filtration flux time tests performed at room temperature showed that the series of ultrafiltration membranes remained relatively stable over a test time of 300 min.Thus,the newly developed mixed matrix membrane showed potential for high efficiency and stability in wastewater treatment containing bovine serum proteins.

数值求解Helmholtz方程问题的超弱-傅里叶贝塞尔算法

应用超弱变分算法数值求解一类Helmholtz方程定解问题,算法使用傅里叶-贝塞尔函数进行逼近,改进了原有算法的数值模拟过程,使得数值计算过程更为简单,数值收敛速度更快,数值实验验证了算法的有效性。

3D printing of poly(ethyleneimine)-functionalized Mg-Al mixed metal oxide monoliths for direct air capture of CO_(2)

Direct air capture(DAC)of CO_(2)plays an indispensable role in achieving carbon-neutral goals as one of the key negative emission technologies.Since large air flows are required to capture the ultradilute CO_(2)from the air,lab-synthesized adsorbents in powder form may cause unacceptable gas pressure drops and poor heat and mass transfer efficiencies.A structured adsorbent is essential for the implementation of gas-solid contactors for cost-and energy-efficient DAC systems.In this study,efficient adsorbent poly(ethyleneimine)(PEI)-functionalized Mg-Al-CO_(3)layered double hydroxide(LDH)-derived mixed metal oxides(MMOs)are three-dimensional(3D)printed into monoliths for the first time with more than 90%adsorbent loadings.The printing process has been optimized by initially printing the LDH powder into monoliths followed by calcination into MMO monoliths.This structure exhibits a 32.7%higher specific surface area and a 46.1%higher pore volume,as compared to the direct printing of the MMO powder into a monolith.After impregnation of PEI,the monolith demonstrates a large adsorption capacity(1.82 mmol/g)and fast kinetics(0.7 mmol/g/h)using a CO_(2)feed gas at 400 ppm at 25℃,one of the highest values among the shaped DAC adsorbents.Smearing of the amino-polymers during the post-printing process affects the diffusion of CO_(2),resulting in slower adsorption kinetics of pre-impregnation monoliths compared to post-impregnation monoliths.The optimal PEI/MeOH ratio for the post-impregnation solution prevents pores clogging that would affect both adsorption capacity and kinetics.

Accurate estimation of Li/Ni mixing degree of lithium nickel oxide cathode materials

Li/Ni mixing negatively influences the discharge capacity of lithium nickel oxide and high-nickel ternary cathode materials.However,accurately measuring the Li/Ni mixing degree is difficult due to the preferred orientation of labbased XRD measurements using Bragg–Brentano geometry.Here,we find that employing spherical harmonics in Rietveld refinement to eliminate the preferred orientation can significantly decrease the measurement error of the Li/Ni mixing ratio.The Li/Ni mixing ratio obtained from Rietveld refinement with spherical harmonics shows a strong correlation with discharge capacity,which means the electrochemical capacity of lithium nickel oxide and high-nickel ternary cathode can be estimated by the Li/Ni mixing degree.Our findings provide a simple and accurate method to estimate the Li/Ni mixing degree,which is valuable to the structural analysis and screening of the synthesis conditions of lithium nickel oxide and high-nickel ternary cathode materials.

Influence of Waveguide Properties on Wave Prototypes Likely to Accompany the Dynamics of Four-Wave Mixing in Optical Fibers

In this article, we study the impacts of nonlinearity and dispersion on signals likely to propagate in the context of the dynamics of four-wave mixing. Thus, we use an indirect resolution technique based on the use of the iB-function to first decouple the nonlinear partial differential equations that govern the propagation dynamics in this case, and subsequently solve them to propose some prototype solutions. These analytical solutions have been obtained;we check the impact of nonlinearity and dispersion. The interest of this work lies not only in the resolution of the partial differential equations that govern the dynamics of wave propagation in this case since these equations not at all easy to integrate analytically and their analytical solutions are very rare, in other words, we propose analytically the solutions of the nonlinear coupled partial differential equations which govern the dynamics of four-wave mixing in optical fibers. Beyond the physical interest of this work, there is also an appreciable mathematical interest.

Mixing planting proportions in a plantation affects functional traits and biomass allocation of Cunninghamia lanceolata and Phoebe bournei seedlings

Functional traits of trees are significantly associated with their adaptation strategies and productivity.However,the effects of species composition and mixing proportion on the functional traits of trees grown in mixed plantations have not been studied extensively.In this study,planting experiments(duration about seven months)were used to study variations in functional traits and biomass allocation of C unninghamia lanceolata(Lamb.)Hook and Phoebe bournei(Hemsley)Yang seedlings in five different mixes(0C:4P,1C:3P,1C:1P,3C:1P,and 4C:0P).Total leaf area per seedling increased in each species as its respective proportion in the mixture decreased.However,the specific leaf area decreased for P.bournei under low percent composition,and the specific leaf area for C.lanceolata differed only marginally among the plantings.The net photosynthetic rates of the two species were higher in the mixed plantings than in their corresponding monocultures,whereas the transpiration rate,stomatal conductance,and instantaneous water use efficiency were not different among the plantings.The average root length and root surface area of C.lanceolata and P.bournei were higher in the mixed plantings than in their monocultures.Specifically,root surface area of C.lanceolate and both root length and surface area of P.bournei increased significantly in the 1C:3P and 2C:2P mixed plantings.Leaf,stem,root,and total dry mass per seedling for C.lanceolata decreased with its increasing percent composition in the mixed plantings,while these variables varied less for P.bournei.The plasticity of biomass allocation was relatively low for both species.Total biomass per planting was higher in the mixed plantings than in the monocultures.Our study indicates that species composition and mixing proportion can considerably affect the functional traits of C.lanceolata and P.bournei.The increase in productivity in the mixed plantings may be partially attributed to low rates of competition between the two species,and future studies should examine the different interspecies relationships.The results of this study can be used to improve plantation productivity and ultimately increase the sustainability of tree products and help to better understand the adaptation strategies of plant coexistence.

Cross-sectional warping and precision of the first-order shear deformation theory for vibrations of transversely functionally graded curved beams

The warping may become an important factor for the precise transverse vibrations of curved beams.Thus,the first aim of this study is to specify the structural design parameters where the influence of cross-sectional warping becomes great and the first-order shear deformation theory lacks the precision necessary.The outof-plane vibrations of the first-order shear deformation theory are compared with the warping-included vibrations as the curvature and/or thickness increase for symmetric and asymmetric transversely-functionally graded(TFG)curved beams.The second aim is to determine the influence of design parameters on the vibrations.The circular/exact elliptical beams are formed via curved mixed finite elements(MFEs)based on the exact curvature and length.The stress-free conditions are satisfied on three-dimensional(3D)constitutive equations.The variation of functionally graded(FG)material constituents is considered based on the power-law dependence.The cross-sectional warping deformations are defined over a displacement-type FE formulation.The warping-included MFEs(W-MFEs)provide satisfactory 3D structural characteristics with smaller degrees of freedom(DOFs)compared with the brick FEs.The Newmark method is used for the forced vibrations.

混合式教学模式下高职“人体机能”课程思政案例

“人体机能”是将生理学、生物化学、病理生理学等多门学科优化、融合形成一门综合性医学基础课程,是高职护理学生的必修课程。从社会主义核心价值观、新时代卫生健康职业精神、辩证唯物主义三个维度充分挖掘蕴含在专业知识中的思政元素,在教学内容中融入思政教育,引导学生树立为人类健康服务的职业责任和无私奉献精神,从而做到育知与育德的有机融合,达到育才和育人的真正统一,落实立德树人根本任务。

基于Copula函数的多站洪水过程随机模拟研究

洪水过程随机模拟能够生成大量与历史洪水统计参数相似且形状各异的洪水过程,而水库群联合防洪调度需要结合流域内各水文站洪水过程统筹洪水资源的调度,实现洪水资源的科学调度,亟需发展多站洪水过程随机模拟方法。鉴于此,提出一种基于Copula函数的多站洪水过程随机模拟方法,该方法先利用二维Copula函数完成主站洪水过程的模拟,然后利用条件混合法构建三维Copula函数,依次模拟其余站的洪水过程。以长江中上游8处水文站为研究对象的结果表明,各站模拟洪水与历史洪水统计参数的相对误差较小,除了北碚和武隆站的最大值外,各水文站统计参数的相对误差在5%左右,能够反映历史洪水过程的统计特征,能够为水利工程防洪规划设计、水库群联合调度及防洪调度风险分析等工作提供支撑作用。

基于混合势函数的永磁同步风力发电机暂态稳定性分析

永磁同步发电机(permanent magnetic synchronous generator,PMSG)作为海上风力发电的主要设备,是风电技术的重要发展方向。然而,PMSG在运行过程中,受到大扰动干扰会导致其暂态稳定性下降。因此,针对PMSG风机大扰动下的暂态稳定性阈值难以判定的问题,本文基于混合势函数理论,建立了PMSG风机系统简化后的混合势函数模型,并推导出PMSG风机在大扰动后的暂态稳定判据。通过仿真后的网侧电流波形和网侧功率波形验证了暂态稳定判据的准确性,并调整各参数数值以分析PMSG风机暂态稳定性与风机参数、故障深度、故障时间和风速的关联性。

基于热分解的舰用复合材料S2/430LV热工参数

为了研究S2/430LV在热分解前后的热工参数,首先利用热重分析仪对氮气环境中S2/430LV复合材料和430LV树脂进行30~800℃环境下热重试验,分析了两种材料在不同升温速率下热分解响应特征;然后,基于阿伦尼乌斯方程,采用微分法与积分法相结合的方法,确定了S2/430LV热分解动力学参数。研究结果表明:430LV树脂和S2/430LV复合材料在氮气环境中均呈现单一热分解过程,纤维织物会促进430LV树脂基体热分解反应;采用Kissinger方程和Flynm-Wall-Ozawa方程确定S2/430LV活化能取值范围;利用Coats-Redfern方程确定S2/430LV最优热分解机理函数和指前因子,从而建立分解率和温度的函数关系式;采用混合定律,建立了考虑材料分解的热工参数模型。研究结果可为舰艇复合材料结构耐火传热性能研究提供有效数据支撑。

长白山主要林分物种多度分布与性状分布的关系

【目的】探究长白山地区群落物种的多度分布格局及其驱动过程,以及多度分布与性状分布之间的关系,为当地森林经营与修复策略的制定提供理论依据。【方法】以长白山不同林分类型的3块5.2 hm2(次生山杨白桦林、次生针阔混交林、原始红松紫椴林)和1块5 hm2原始阔叶红松林固定监测样地为研究对象,通过采集样地内木本个体的6个关键功能性状(叶面积、比叶面积、叶片厚度、最大树高、叶片氮含量、叶片磷含量),分析样地的物种多度分布格局、功能性状分布格局以及二者之间的关系。【结果】不同林分类型中通过统计检验的模型种类各异,但所有最优模型均为统计模型。在性状分布格局中,最大树高、比叶面积和叶磷含量在4块样地均呈现正态分布。然而,功能性状分布格局转化得到的物种分布格局模型显示,尽管部分模型通过了统计检验,但与多度分布结果拟合度不高。【结论】在长白山地区,物种多样性的形成并非主要由随机过程驱动,而是受到竞争作用的显著影响,这决定了演替过程中群落物种组成的变化情况。虽然功能性状分布与物种多度分布之间存在一定的联系,但直接通过群落水平性状分布格局推断物种多度的方法尚不准确。

基于POI数据的双流区城市用地功能识别及其混合度评价研究

基于POI数据,利用频数密度、类型比例等方法对双流区城市用地类型进行识别,并对城市土地利用混合度进行分析,揭示城市土地利用功能现状。结果表明:1)双流区城市土地利用空间上呈现出由北向南组团集中—零星分散的分布格局,中心城区各类用地布局相对较为集中。2)土地利用的单一功能占比较大,呈现出大区域辐射分布的空间格局,多功能区主要集中于城市中心区域,呈现出聚集组团分布的特征,两者“中心—外围”的圈层分异明显。3)双流区城市土地利用混合度总体程度偏低,且呈现团状集聚分布与点状分散分布相结合的空间格局,地区之间差异明显。

一种求解混合变分不等式的带有扰动项的神经网络方法

通过构建带有干扰项的新型神经网络求解混合变分不等式问题.主要将已有的固定时间收敛的前向-后向-前向神经动力学网络进行推广,构建出带有扰动项的神经网络模型.证明了所构建的神经网络的平衡点是固定时间稳定的,并给出了稳定时间的上界.最后通过数值实验证明了该方法的有效性.

基于YOLOv8的鲁棒西红柿目标检测方法

针对当前复杂环境下基于YOLO系列西红柿目标检测算法识别精确率不高、错检和漏检情况较多等问题,提出了一种基于YOLOv8单阶段西红柿目标检测识别方法.该方法以YOLOv8单阶段目标检测算法为主体,结合CSPDarknet结构改进、引入注意力机制、使用自适应锚框和混合损失函数等,提高算法检测精确率和效率.实验结果表明,YOLOv8模型在复杂环境下依然能够高效、准确地识别西红柿目标,展现出良好的鲁棒性,为农业自动化中的目标检测提供了可靠的技术支持.

因地制宜、乘势而上,打造海岛县城综合性城市节点——温州市洞头区同心广场交通旅游综合体策划研究

县城建设是新时代县域发展的核心部分。洞头是全国十四个海岛区县之一,人口规模小、建设空间有限、优质项目稀缺,如何利用有限的资源,实现长三角一体化背景下的“海上花园”定位,是它面临的重大发展挑战。同心广场是洞头目前为数不多的重点项目,如何利用这个机会,发挥超越项目本身的效用,为完善城市功能作出额外贡献,是进行本次策划研究的核心理念。本项目站在县域整体发展的角度,策划海陆交通、酒店住宿、综合商业、高端商务、文化展示、休闲娱乐等六大业态,因地制宜地将原本单一功能的客运中心提升为城市增量建设的综合性节点,进而发挥“引火柴”的效应,成为推动洞头高质量发展的活力引擎。这将为今后海岛县城应对新时代发展的复杂挑战、探索新型城镇化建设路径提供可资借鉴的经验。

基于MXI测度的街区功能混合类型及分布特征解析——以南京老城区为例

功能混合是城市集约发展和活力提升的关键因素,街区是功能混合的关键尺度层级,其混合测度有助于存量空间功能布局的认知和评估。选用功能混合指数(MXI)来测度南京老城街区单元的功能构成,通过测度结果的GIS地图映射和类型分析,呈现不同功能混合街区单元的空间分布,解析街区功能混合类型的分布与老城区位及空间结构的关联性,归纳街区混合类型的空间分布模式,并提示低混合度街区可能存在的问题。

基于POI数据的城市功能区识别及混合度计算

针对城市功能区识别现状,将传统功能区识别研究与大数据进行有机结合,以合肥市主城区为研究对象,以POI数据为基础,对它进行预处理并赋予相应指标权重,运用频数密度、类型比例以及绝对信息熵研究方法,对单位网格内城市用地功能进行识别,并在此基础上计算城市用地功能混合度。研究结果表明,合肥市主城区功能用地在整体上呈现“中心+放射状”的空间布局形式;商服、居住、道路设施以及公共服务设施用地均呈现出相对聚集的密度分布核心,工业和绿地广场用地呈现分散分布的空间特征;混合用地多集中于城区中心,由中心向外用地功能混合度逐渐降低,用地集约性逐渐减弱。经过对比检验,整体识别结果较好。研究可为提升城市用地集约化发展、促进城市用地混合利用提供理论参考和实践基础。

3种混交林造林初期土壤真菌群落结构特征

土壤微生物是参与陆地生态系统生物地球化学循环过程的重要成员。造林可以显著影响土壤微生物群落结构与功能,但造林初期驱动的土壤理化因子变化对土壤微生物结构与功能的影响尚不清楚。通过分析由珍稀乡土树种组成的三种新造混交林(BB:银杏Ginkgo biloba⁃桢楠Phoebe zhennan;CB:香椿Toona sinensis⁃红豆杉Taxus wallichiana⁃桢楠Phoebe zhennan;MB:鹅掌楸Liriodendron chinense⁃乐昌含笑Michelia chapensis⁃香椿Toona sinensis⁃玉兰Yulania denudata)表层(0—20 cm)土壤真菌群落组成、功能类群及其土壤理化因子,并以草灌化未造林地作对照(CK),研究土壤真菌群落结构和功能对不同林型造林初期的响应。结果表明:(1)不同林型土壤真菌群落丰富度、多样性指数高于CK,表现为MB>BB>CB>CK,主要受到土壤孔隙度、水解性氮的影响。(2)土壤真菌门水平优势类群在不同处理间无显著差异,其中子囊菌门占绝对优势,MB中的被孢霉门相对丰度显著高于CK(P<0.05)。与CK相比,球囊菌门与Leptodiscella相对丰度在各林型中均降低。(3)通过非度量多维尺度(NMDS)与置换多元方差(Adonis)分析表明,造林初期,造林土壤真菌群落结构与CK存在显著差异(P<0.01)。冗余分析(RDA)分析表明全钾、水解性氮、土壤容重及土壤碳氮比是影响真菌群落指示种的主要土壤理化因子;被孢霉门与水解性氮、碳氮比、全氮、非毛管孔隙度、含水率均呈正相关,与全钾呈负相关。(4)真菌群落主要以腐生营养型为主,病理营养型次之;造林后腐生营养型真菌相对丰度降低,而土壤腐生菌的相对丰度在BB与MB处理中反而显著增加(P<0.05);MB处理中动物病原菌的相对丰度显著增加(P<0.05);真菌优势功能类群主要受到土壤pH、土壤孔隙度、土壤碳氮比(C/N)、土壤有机质、全氮、全钾的影响。造林初期土壤真菌群落结构与功能类群发生了显著改变,阔阔混交林较针阔混交林变化更加明显,其中多种阔叶树混交林病原菌相对更高。

改进YOLOv5s的铁路异物入侵检测算法

行人、车辆等异物侵入铁路界线,严重威胁行人安全和铁路交通安全.针对传统铁路异物入侵检测方法精度低、时效性差等问题,提出改进YOLOv5s算法的铁路异物入侵检测模型SD-YOLO.本文提出SSA混合注意力机制,加强模型的局部表征能力,提高小目标识别效果;提出DW-Decoupled Head解耦检测头,加快网络收敛速度;引入边界框回归损失函数SIoU,提高了模型的检测精度;使用转置卷积作为采样方法,采样更适合铁路侵限障碍物特征的尺寸和比例.在数据集RS和Pascal VOC 2012进行实验验证,与基线YOLOv5s算法相比,平均精度mAP@0.5分别提高了2.7%、1.8%,mAP@.5:.95分别提高了2.9%、2.1%,检测速度分别达到79 FPS和78 FPS,表明该算法在检测精度和速度上均取得良好的性能,有效改善了漏检、误检问题,提高了小目标识别能力.