磁性高分子微球的制备方法与发展趋势

磁性高分子微球作为一种新型功能材料,兼具高分子微球的众多特性和磁响应性,在靶向药物、细胞分离、细胞标记、固定化酶和生物传感器等领域有着广阔的应用前景.综述了各类磁性高分子微球的制备方法及各自的优缺点,概述了磁性高分子微球的重要参数及表征方法,预测了高分子微球研究工作的趋势.     

生物高分子磁性微球的研究进展

磁性高分子微球是近二十年来研究的一类新型功能材料。拟从生物高分子磁性微球的制备、结构、性能和应用等几个方面综述近年来国内外有关磁性高分子微球的研究状况。     

磁性高分子微球研究进展

对磁性高分子微球的研究进展进行了综述，介绍了各类微球的制备方法及相关原理。在此基础上，概述了磁性高分子微球在磁性塑料、固定化酶、细胞分离和靶向药物等领域的应用情况，并对磁性高分子微球的未来研究方向进行了展望。     

关于在水处理领域中的磁性材料的应用

近年来,对于磁性微球的研究作为磁性功能材料的一个重要发展方向得到了人们的广泛关注。鉴于此,文章对磁性微球在水处理应用方面,特别是对天然生物高分子功能化、合成高分子功能化的磁性微球在水处理中的应用及磁性微球对废水中微量有机物的检测方面的应用现状进行了详细介绍,并指出磁性微球在废水处理方面有广泛的应用前景及未来发展方向。     

磁性高分子复合微球的制备

通过选用含有乙烯基的有机硅烷偶联剂对自制的纳米Fe3O4进行表面修饰后,采用悬浮聚合法成功制备了单分散磁性高分子复合微球,并重点研究了分散剂浓度、搅拌速度、磁含量等因素对制备的磁性高分子复合微球的影响.结果表明,合适的分散剂浓度和搅拌速度可以获得球径分布良好的磁性高分子复合微球,微球的磁感应强度可以通过改变Fe3O4磁性粒子的含量进行调节.     

磁性高分子微球的研究进展

概述了磁性高分子微球的研究近况，讨论了磁性高分子微球的分类，制备方法，表征手段及其应用，并对这一领域的发展进行了展望。     

磁性高分子微球的制备及在分析化学中的应用进展

在总结近年来国内外有关磁性高分子微球研究成果的基础上,阐述了磁性高分子微球的结构类型、特点、目前的各种制备方法、袁征以及在分析化学领域的最新应用进展,指出了当前研究中需要解决的问题.     

Fe3O4/聚合物磁性高分子微球的制备

近年来,对于磁性高分子微球的研究作为磁性功能材料的一个重要发展方向得到了人们的广泛关注.鉴于此,详细介绍了近年来国内外Fe3O4磁性高分子微球的制备方法,分析讨论了各种制备方法存在的一些问题,同时简单介绍了活性自由基聚合技术在此领域内的应用,并对微球的发展趋势进行了展望.     

微波辐射乳液聚合制备磁性高分子微球

用化学共沉淀法制备了Fe3O4纳米粒子,并用油酸和十二烷基硫酸钠对Fe3O4纳米粒子进行表面修饰,得到了稳定的水分散性纳米Fe3O4磁流体。在Fe3O4磁流体存在下,以苯乙烯和丙烯酰胺为单体,采用微波辐射乳液聚合法制备了Fe3O4/聚(苯乙烯-丙烯酰胺)磁性高分子微球,表征了磁性高分子微球的形态与结构,研究了磁性高分子微球的粒径、热稳定性、磁含量与饱和磁化强度。研究发现,在选定合适的聚合条件下,通过微波辐射乳液聚合法可以制得粒径为70 nm~80 nm、磁含量为18.2%的磁性高分子微球。     

Fe_3O_4/聚苯乙烯磁性复合微球的制备与应用前景

采用改进的乳液聚合法,制备了磁性Fe3O4为核、苯乙烯和丙烯酸的共聚物为壳的磁性高分子复合微球。在透射电镜下观察磁性微球的粒径在130 nm左右;并用FT-IR、XPS和热失重方法表征了复合微球的组成成分、羧基(-COOH)的含量及所含Fe3O4的百分量。结果表明,微球的粒径分布均匀,大小可控,稳定性好,具有一定的抗溶剂性能,可长时间存放,是纳米磁性高分子聚合物网络的雏形。     

Conservation de hachis de sardine en entreposage à l'état congeléà - 20°C: hachis obtenus à partir de sardine entière, et de sardine étêtée et éviscérée

This Paper presents a comparative study of minces prepared from headed and gutted sardines and minces prepared from whole sardines, with a view to avoiding unnecessary product handling and improving yields. Certain additives (cryoprotectants and antioxidants) were blended into some of the mince lots in an attempt to extend their storage life, and in one of the lots the mince was washed prior to mixing. The minces were prepared by extrusion and the lots were fashioned into 4 cm thick 700 g blocks, frozen in a horizontal plate freezer until a core temperature of −20°C was attained, vacuum packed and stored at −20°C for 12 months. Proximate analysis, minerals analysis (Na,K,Mg,Ca,Fe and Cu) and yield measurements were carried out prior to freezing. Protein solubility, emulsifying capacity, cooking loss, K value, pH, TBA index, viable germ counts, entero and coliform bacteria, instrumental texture analysis and sensory analysis were periodically measured. The results obtained can be summarized as follows: the method of extrusion appears to be particularly well adapted to whole fish with regard to the avoidance of handling and improving yields. In relation to mineral content the only appreciable difference is a higher sodium content in minces made from whole fish (E lots) than in minces made from gutted and headed sardines (D lots), while in the washed lots there was an appreciable decreases in the amounts of Cu, Fe, Mg and K. Protein solubility stayed at higher levels in the E lots than in the D lots, though it was high in both types of mince at the end of storage: the use of protein cryoprotectants is advisable particularly in the washed D lot (DL) and in the E lots when storage of >6 monts is required. The emulsifying capacity, which was initially higher in the E lot than in the D lot, stabilized after the second month of storage. The effect of the protein cryoprotectants was to increase slightly the emulsifying capacity, which remained higher than in the control lots throughout the storage period, even in the DL lot, which the authors feel is important with regard to the use of these minces in sausage-type products. Cooking loss was initially higher in the D lots, but after the fourth month of storage it was the same for both types. The protein cryoprotectants reduced cooking loss and were more effective in the E lots. Due to fluctuations in K values obtained, the authors do not regard them as a reliable indicator of product quality. The pH was slightly more basic in the E lots than in the D lots, and pH increased in the additive-containing lots, especially in the washed mince preparation. The TBA index only showed significant differences between the D and E lots in the final test performed. The antioxidants appeared to be more effective in the E lots than in the D lots. Washing also delayed the onset of randicity, probably through the removal of fat and catalysts with the wash water. No synergistic effect was observed between the protein cryoprotectants and the antioxidants. The total initial count of micro-organisms was substantially higher in the E lots than in the D lots because of the intestinal content, though the levels equalized during storage and at no time exceeded allowable limits. Washing did not significantly decrease germ counts. The initial excessive amounts of enterobacteria in the E lots decreased during storage, whereas the level of caliform bacteria, on the other hand, remained constant. In the E lot without additives (ESS), however, Escherichia coli was detected prior to freezing but not in any of the subsequent analyses. In general, texture as determined by instrumental methods (hardness, firmness, elasticity, and cohesiveness) gave higher values for the D lots than for the E lots. Washing increased hardness and firmness while cryoprotectants reduced them. Cooking considerably hardened the samples in the case of the D lots but did not cause variations in the E minces. Hardness and firmness remained quite stable, although there was a slight increase in the cryoprotectants-free lots and washed minces. Elasticity tended to increase in the E lots during storage, and this effect was more pronounced in the cryoprotectants-free lots; cryoprotectants had the effect of decreasing elasticity and stabilizing it in the D lots, although they were higher in the D lots than in the E lots. Elasticity and cohesiveness remained constant in the washed mince. Cohesiveness increased in all the lots during storage, and the cryoprotectants exerted no effect on this parameter. In connection with the sensory analysis, a certain sweet taste was perceived in the cryoprotectants-containing D lots, slightly reducing the quality of the product, though it was not found unpleasant and was barely detectable in the E lots. The typical sardine flavoured lots by the washed mince reduced its acceptance, though this opens up a series of technological possibilities for it. A rancid taste was detectable in the ESS lot after five months in storage, in the E lot with protein antidenaturants (ESP) after eight months, and in the E lot that contained antioxidants (ESAO) and protein antidenaturants and antioxidants (ESA), in the last test carried out.     

Experimental investigation of oil retention in air conditioning systems

In air conditioning and refrigeration systems a small amount of oil is carried with the refrigerant and is retained in the system components. Oil retention characteristics in the condenser, evaporator, liquid and suction lines were measured and are presented and discussed here. Refrigerants R22, R410A, and R134a with miscible and non-miscible lubricants were considered to investigate oil retention physics in the widest possible range of transport properties. A parametric analysis in the suction line showed that oil retention depends on the oil mass fraction, vapor refrigerant mass flux, mixture viscosity ratio and orientation of the pipe. In the suction line, an increase in mixture viscosity of about 55% caused a rise in oil retention in the range of 50%, depending on the oil mass fraction. Oil retention in the upward vertical suction line is about 50% higher than in the horizontal line at similar conditions.     

Hollow‐Structured Mesoporous Materials: Chemical Synthesis,Functionalization and Applications

Hollow‐structured mesoporous materials (HMMs), as a kind of mesoporous material with unique morphology, have been of great interest in the past decade because of the subtle combination of the hollow architecture with the mesoporous nanostructure. Benefitting from the merits of low density, large void space, large specific surface area, and, especially, the good biocompatibility, HMMs present promising application prospects in various fields, such as adsorption and storage, confined catalysis when catalytically active species are incorporated in the core and/or shell, controlled drug release, targeted drug delivery, and simultaneous diagnosis and therapy of cancers when the surface and/or core of the HMMs are functionalized with functional ligands and/or nanoparticles, and so on. In this review, recent progress in the design, synthesis, functionalization, and applications of hollow mesoporous materials are discussed. Two main synthetic strategies, soft‐templating and hard‐templating routes, are broadly sorted and described in detail. Progress in the main application aspects of HMMs, such as adsorption and storage, catalysis, and biomedicine, are also discussed in detail in this article, in terms of the unique features of the combined large void space in the core and the mesoporous network in the shell. Functionalization of the core and pore/outer surfaces with functional organic groups and/or nanoparticles, and their performance, are summarized in this article. Finally, an outlook of their prospects and challenges in terms of their controlled synthesis and scaled application is presented.     

Distribution of heavy metals in Lakes Doirani and Kerkini, Northern Greece

The distribution of heavy metals in two lakes of high ecological significance, Doirani and Kerkini, located in Northern Greece was studied. Eight metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) were determined in water, total suspended solids, fine and coarse sediments. Moreover, the modified BCR fractionation scheme was employed in sediments and suspended solids to determine soluble, oxidisable, reducible and residual fractions of metals. The Lake Doirani presents higher metal concentrations in aqueous phase than Lake Kerkini; Cd, Cu, Ni, Pb and Zn are above the chronic freshwater quality criteria for aquatic life. In both lakes, Fe and Mn are the most abundant elements in total suspended solids whereas Cd the less abundant. The Lake Kerkini exhibits higher concentrations of all the examined metals in sediments comparing to the Lake Doirani, however the concentrations are lower than the sediment quality guidelines. Cd in sediments is mainly in soluble fraction, Pb and Cu exhibit significant oxidisable fractions whereas, Cr and Fe associated mainly with residual fraction.     

Zr在7050铝合金中的行为与作用的电镜观察

本文研究了含Zr的高强7050铝合金中Zr化合物的存在形态,尺寸和分布特点。TEM观察表明,锭铸中的Zr以ZrAl_3初晶和固溶体两种形式存在;均匀化处理的铸锭中,球形的ZrAl_3在基体上呈共格与非共格形式弥散析出,尺寸约为10～30nμ,热轧变形后,ZrAl_3大都钉轧在位错线和小角晶界上,其形态和尺寸没有明显改变;淬火后,可观察到大量存在的亚结构和亚晶粒,球形ZrAl_3质点分布在亚晶界、晶内以及位错线上,非共格的ZrAl_3周围有η相非均质成核;与含Cr的该系合金相比较,可看到E相尺寸远大于含Zr合金中的ZrAl_3质点,而ZrAl_3周围非均质成核的η相的尺寸和数量要比E相周围的小得多;淬火后经时效和双级过时效热处理,ZrAl_3质点的形态、尺寸和分布,均无显著变化。利用上述实验结果,可以园满地解释Zr对7050铝合金细化晶粒、提高再结晶温度、降低淬火敏感性以及提高强度和抗应力腐蚀性能的作用。     

Servitization of manufacturing in the new ICTs era: A survey on operations management

Servitization of manufacturing has become one of the main pathways for transition and upgrade in the manufacturing industry. New information and communication technologies (ICTs), such as the Internet of Things, Big Data, and Cloud Computing have enabled the servitization of manufacturing in terms of value creation, resource management, and supply chain management. This study presents a comprehensive review on the servitization in operations management in the era of new ICTs. A new value chain framework is proposed under the business model that revolves around servitization, which showcases the new activities and ways of implementation in the era of new ICTs. The virtualization, configuration, and evaluation of integrated manufacturing and service resources are analyzed. In particular, the methods used in new ICT-supported resource management platforms are surveyed. Problems in the supply chain management in manufacturing services (including the selection of partners, as well as the coordination, planning, and scheduling among members) are presented. This study concludes with a discussion on state-of-the-art servitization in operations management in the era of new ICTs.     

Condition, safety and cost profiles for deteriorating structures with emphasis on bridges

After an enormous investment in construction of highway networks undertaken in the second half of the 20th century, the highway networks of most European and North American countries are now completed or close to completion. As a result, the need in funding changed from building new highway structures to repair, rehabilitation, and replacement the existing ones. In this paper, a model for analyzing the evolution in time of probabilistic performance indicators of existing structures, in terms of condition, safety, and cost under no maintenance, preventive maintenance, and essential maintenance, is presented. This model integrates the current practice in bridge management systems based on visual inspections (condition index) with structural assessment (safety index) during the lifetime of existing structures. The proposed model allows the consideration of uncertainties in the performance deterioration process, times of application of maintenance actions, and in the effects of maintenance actions on the condition, safety, and life-cycle cost of structures by defining all parameters involved in the model as random variables. Interaction between condition and safety profiles is defined through probabilistic and deterministic relations. The probabilistic characteristics of the condition, safety, and cost profiles of deteriorating structures are computed by Monte-Carlo simulation. Several realistic examples, based on data on highway bridge components gathered in the United Kingdom, are presented.     

Thermophysical properties: What have we learned recently,and what do we still need to know?

Some recent developments in the areas of measurement, prediction, and correlation of thermophysical properties and phase behavior are reviewed. However. important problems remain, and some of these are not being addressed. Here a number of thermophysical properties problem areas are identified based on the prejudices of the author and a small survey of friends and colleagues in industry and academia. Many of the problems arise as result of changes in industrial emphasis, for example, from chemicals to materials and pharmaceuticals, changes in federal or local regulations permitting lower air and water emissions, changes in technology, and an interest in determining the fate of chemicals in the environment. Some of the research needs, both experimental and theoretical. to deal with these problems are discussed.     

基于沉浸理论的农区畜牧业服务设计研究

目的 探究沉浸理论介入农区畜牧业服务设计的策略,构建更具用户体验感的农区畜牧业服务设计系统。方法 根据沉浸理论的内涵与我国农区畜牧业发展现状,分析沉浸理论介入农区畜牧业服务设计的经济价值、社会价值和文化价值,针对农区畜牧业存在的问题及沉浸理论可行性分析,构建沉浸理论下的农区畜牧业服务设计策略。结果 首先对河南省新野县畜牧业现状进行调研分析;其次基于服务设计思维与设计策略进行服务系统图及蓝图设计,并进一步设计以用户为中心的服务载体——恒永牧场APP、畜牧市集及配套应用小程序,来实现新野农区畜牧业用户的沉浸式体验;最后通过沉浸效果评估,验证了沉浸理论介入农区畜牧业的可行性及重要性。结论 沉浸理论的融入能够改善用户体验,促进农区畜牧业的高质量发展,为我国畜牧业服务系统的创新设计提供了新的思路和方法。