Determining the order of the functional autoregressive model

We propose a multistage testing procedure to determine the order p of a functional autoregressive process, FAR (p). At its core is the representation of the FAR(p) process as a fully functional linear model with dependent regressors. Estimating the kernel function in this linear model allows us to construct a test statistic which has, approximately, a chi–square distribution with the number of degrees of freedom determined by the number of functional principal components used to represent the data. The asymptotic justification relies on the concept of L^p–m–approximability which quantifies the temporal dependence of functional time series. The procedure enjoys very good finite sample properties, as confirmed by a simulation study and applications to functional time series derived from credit card transactions and Eurodollar futures data.     

功能化ABS的研究进展

综述了功能化ABS的发展概况,并对国内外新型功能化ABS在阻燃、抗菌、电磁屏蔽等领域的研究情况做了详细介绍,最后对新型功能化ABS的发展前景做了展望。     

木质素基功能材料的制备与应用研究进展

木质素是植物中含量第二大的天然有机高分子聚合物,以来源于制浆造纸和生物质炼制中的工业木质素为原料,制备具有特殊功能的高附加值材料,对木质素进行资源化高效利用、解决化石资源日趋紧缺及环境污染等问题具有重要意义。近年来,研究人员利用各种技术制备了许多种类的木质素基功能材料,如载药微胶囊、防紫外剂、抗老化剂、光催化剂载体、炭电极材料等。本文介绍了木质素基功能材料的国内外最新研究进展,总结了木质素基功能材料的不同制备工艺和应用领域,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。指出木质素基功能材料的研究是涉及多个学科交叉的前沿课题,但如何高效制备结构规整可控且性能优异的木质素基功能材料仍然是一个具有挑战性的课题。今后的研究应加强对木质素微观结构及其调控机理的研究,以便可以更好地利用其自身的三维网状结构和大量芳香结构等特性制备基于木质素特性的功能材料。     

活性污泥中功能性优势未培养微生物的强化与检测研究进展

阐述功能性未培养微生物强化研究的重要性,介绍了主要包括营养补充法、Biolog法、分子生态学技术的功能性未培养微生物的强化手段,以及主要包括分子生物学技术(DGGE、T-RFLP、RFLP、ARDRA、T-RFLP)、生物标记物法(脂肪酸图谱分析术、醌类图谱分析术)的功能性优势未培养微生物强化后的检测策略。通过这些方法对激活前后的活性污泥中功能性未培养微生物的代谢活性、降解COD能力提高与否进行检测。其目的是优化筛选出能激活功能性优势未培养微生物的激活剂,最终达到提高活性污泥对废(污)水的处理能力。     

Exploring the effect of functionalization of graphene on the quantum capacitance by first principle study

Graphene is considered as one of the most promising electrode materials for supercapacitors. Despite many advantages of graphene-based electrodes, there remains a major limitation, which is low value of specific capacitance. This limitation is observed in graphene-based electrodes’ due to their low quantum capacitance. The present article explored the variations of quantum capacitance of graphene sheets through their functionalization with monovalent and divalent functional groups. The findings of this report demonstrate that functionalization of graphene may improve the gravimetric quantum capacitance compared to pristine graphene. The monovalent functional groups show symmetric behavior in negative and positive applied voltages. They have a significant effect on the quantum capacitance, especially at low voltages. In contrast, the divalent functional groups show asymmetric behavior in negative and positive applied voltages. They have an additive effect on the quantum capacitance, especially at higher voltages and negative bias. However, both kinds of functional groups enhance the quantum capacitance compared to pristine graphene.     

21世纪的功能高分子材料

介绍了功能高分子材料的发展状况，展望了未来的功能高分子材料的发展趋势。     

抗静电涤纶功能纤维制备技术研究进展

在功能纺织品开发的背景下,为更好理解涤纶抗静电机制,制备性能优异的抗静电涤纶,详细阐述了我国抗静电涤纶制备的常用方法,包括应用抗静电剂对纺织品的纤维表面进行整理、金属/炭黑等导电物质表面镀层、化学共聚改性、共混纺丝改性、表面接枝改性和生物酶表面处理等,最后总结了抗静电涤纶制备中存在的问题,展望了其在该领域的发展方向,为...     

探讨生物反馈对老年习惯性功能性便秘的临床疗效

目的评价生物反馈方法治疗功能性便秘的疗效。方法对我院171例习惯性功能性便秘患者进行生物反馈治疗,治疗前后进行临床评估、肛门直肠动力分析。结果经过生物反馈治疗后患者临床症状有了极大的改善。生物反馈治疗习惯性功能性便秘有效。     

分子印迹功能单体选择方法研究进展

分子印迹技术是以一种化合物作为模板,制备出对该模板分子具有特定＂记忆功能＂的聚合物。在分子印迹技术中,功能单体的选择对分子印迹聚合物的识别性能起着至关重要的作用,总结了近些年关于预测功能单体的分析方法及其分析原理,并做了详细的介绍。     

Use of GPC-UV to determine the location of functional groups in styrenic polymers

Gel permeation chromatography (GPC) is one of the most important characterization tools of the polymer chemist. The coupling of GPC with ultraviolet (UV) spectroscopy (GPC–UV) increases the power of the tool even further. This article describes the use of GPC–UV to determine the location of functional groups in polymers. This information is important for characterization of functionalized polymers being used as building blocks for making block and graft copolymers, and for the elucidation of polymer degradation mechanisms. The use of GPC–UV for quantitation of the level of functional groups is hampered by the inability to achieve complete conversion of some UV transparent functional groups (e.g., hydroxyl and carbonyl) to the uniquely absorbing derivative needed for the analysis. Attempts to quantitatively derivatize polymer-bound functional groups using conditions developed for model compounds failed. However, the use of GPC–UV to locate functional groups in polymers (pendant vs. chain-end) is clearly demonstrated.     

Effects of functional groups on the mechanical and wrinkling properties of graphene sheets

The effects of the degree of functionalization, molecular structure and molecular weight of functional groups on the Young’s modulus of graphene sheets were investigated through molecular dynamics and molecular mechanics simulations. The dependence of shear modulus, strength and critical wrinkling strain of graphene sheets on the chemical functionalization was also examined. It is found that Young’s modulus depends greatly on the degree of functionalization and molecular structure of the functional groups, while the molecular weight of the functional groups plays a minor role in determining Young’s modulus. The chemical functionalization also reduces the shear modulus and critical wrinkling strain. The binding energy between the functional groups and the graphene sheets is mainly responsible for these findings.     

改性黏土对染料工艺废水处理的研究

采用氯化十二烷基二甲基苄基铵改性后的改性黏土吸附剂Y处理不同类型的染料工艺废水.通过实验研究不同条件下,不同类型废水COD和色度的去除率以及吸附规律,探讨活性黏土和改性黏土吸附剂Y所带官能团与其降低废水中COD和色度的规律.     

Five Functional Aspects of the Epidermal Barrier

The epidermis is a living, multilayered barrier with five functional levels, including a physical, a chemical, a microbial, a neuronal, and an immune level. Altogether, this complex organ contributes to protect the host from external aggression and to preserve its integrity. In this review, we focused on the different functional aspects.     

反应挤出技术在聚烯烃功能性棚膜生产中的应用

介绍了反应挤出技术在聚烯烃功能性棚膜中的应用现状,结合反应挤出技术的新发展探讨了其在聚烯烃功能性棚膜生产中的应用前景及发展优势。     

Evaluation of the Correlation between Porphyrin Accumulation in Cancer Cells and Functional Porphyrin Positions of the Phenyl Group

Porphyrin selectively shows tumour accumulation and has attracted attention as a carrier molecule for drug delivery systems (DDS). Porphyrin has two functional sites termed the meso- and β-positions. In previous work, meso-porphyrin derivatives with an alkyl group were found to exhibit greater accumulation in human breast cancer cells (MCF-7). To identify the correlation between porphyrin accumulation and functional porphyrin positions of other functional groups, the accumulation of porphyrin derivatives with a phenyl group was investigated. The β-porphyrin derivative with a phenyl group showed higher accumulation in MCF-7 cells and greater affinity for albumin than the meso-porphyrin derivative. The results of density functional theory (DFT) calculations suggest that the β-porphyrin derivative with a phenyl group had higher planarity across the total structure than the meso-porphyrin derivative. It was concluded that the greater planarity of the β-porphyrin derivative with a phenyl group might lead to superior MCF-7 cell accumulation.     

面向21世纪的功能高分子材料

介绍了导电材料,热电材料,智能材料,感光材料,生物医用高分子材料等的应用研究与发展状况,展望了未来的功能高分子材料的发展趋势。     

Thermal study on the copolymers of phthalonitrile and phenylnitrile‐functional benzoxazines

Ortho‐, meta‐, and para‐phenylnitrile–functional benzoxazines are polymerized at different compositions with phthalonitrile‐functional monomers providing copolybenzoxazines of high thermal stability and easy processability. The most positive effect on these properties is obtained on copolymerizing phthalonitrile‐ and ortho‐phenylnitrile–functional benzoxazines. Thermal decomposition of these polybenzoxazines is studied by thermogravimetry (TGA). It is demonstrated that only 30 mol % of phthalonitrile‐functional benzoxazine added to the ortho‐phenylnitrile–substituted monomer improves char yield significantly from 59 to 77 wt %, which is the value of neat phthalonitrile‐based polybenzoxazine. Glass transition temperature (T_g) also dramatically increases from 180°C for neat ortho‐phenylnitrile polymer to 294°C for the copolymer with 30 mol % of phthalonitrile‐functional monomer. Additionally, the high melt viscosity of phthalonitrile‐functional benzoxazines is dramatically decreased upon blending with phenylnitrile‐functional monomer. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2937–2949, 1999     

杂环轮烯类化合物密度泛函理论研究

运用量子化学中的密度泛函和含时密度泛函理论法,计算了四种加共轭环的脱氢苯[15]轮烯衍生物的几何构型、电子结构、前线分子轨道和电子光谱性质。计算结果表明当脱氢苯[15]轮烯分子(M)被杂环取代或增加分子的共轭性,对轮烯的键长和键角等结构参数的影响不大,这与轮烯具有较强的共轭性有关。当母体中的苯环被嘧啶环取代时,最大吸收波长蓝移;当母体中的苯环被萘取代时,最大吸收波长与母体中的苯被吡嗪取代时的最大吸收波长相近。     

浅议我国功能性纺织品开发现状及发展趋势

对我国功能性纺织品的分类及开发现状进行了介绍,对功能性纺织品的制备方法进行了阐述,对功能性纺织品的最新进展及其发展趋势进行了展望。     

Effect of functional monomer on the stability and film properties of thermosetting core-shell latexes

Functionalized core-shell latexes were prepared by copolymerization of butyl acrylate and methyl methacrylate with 2-hydroxyethyl methacrylate (HEMA) or methacrylic acid (MAA), which were added during the first or second stages of polymerization, respectively. The HEMA and MAA concentrations were increased while the equivalent ratio of functional groups remained constant. Colloidal stability, particle size, particle size distribution, film properties and morphology were studied as functions of functional monomer content. The upper limit functionality content was limited by the stability of the system during synthesis. A bimodal particle size distribution was observed for high concentrations of functional monomers. Increase in carboxyl and hydroxyl functionalities improved tensile strength and modulus for un-crosslinked films, and generally higher tensile strength, tensile modulus and storage modulus at high temperature were obtained after the functional latexes were crosslinked with a cycloaliphatic diepoxide.