STUDY ON THE ANALYTICAL MODEL OF DECAY OF MESOSCALE EDDY ON THE CONTINENTAL SHELF

Observations indicate that the motion of an oceanic mesoscale eddy entering the conti-nental shelf will quickly decay. This shows that the surface area of the eddy continuouslyexpands, and the rotational angular velocity gradually decays with time. Starting from avorticity equation for a vertically stratified, horizontally uniform fluid the above process isdynamically analyzed in this paper. Under the condition to consider the Ekman pump effectof the upper and lower boundary layers and side friction, the analytical models for thesurface area expansion and angular velocity decay of the eddy are deduced.     

介观层次上的计算机模拟和应用*

本文综述了近年发展起来的介观层次上的计算机模拟和应用。介绍了两种较为成熟的模拟方法: 介观动力学和耗散颗粒动力学。还介绍了介观模拟方法在胶束形成、胶体絮状物构造、乳化剂、流变学、共聚物和高分子混合形态以及通过多孔介质的流动研究中的应用。     

Controlled evaporative self-assembly of polymer nanoribbons using oscillating capillary bridges

Evaporative self-assembly (ESA), based on the “coffee-ring” effect, is a versatile technique for assembling particle solutions into mesoscale patterns and structures on different substrates. ESA works with a wide variety of organic and inorganic materials, where the solution is a combination of volatile solvent and nonvolatile solute. Modified ESA methods, such as “stop-and-go flow coating,” use a programmed meniscus “stick–slip” motion to create mesoscale assemblies with controlled shape, size, and architecture. However, current methods are not scalable for increased production volumes or patterning large surface areas. We demonstrate a new ESA method, where an oscillating blade controls the meniscus depinning and drives the evaporative assembly of solutes at the pinned meniscus. Results show that oscillation frequency and substrate speed control time/distance intervals between successive meniscus depinning, and the assembly dimensions depend on solution concentration, oscillation frequency, substrate speed, and meniscus height. We report the mechanism of the meniscus depinning and the control over assembly cross-sectional dimensions. This advance provides a scalable ESA method with faster processing times and maintained advantages. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018 , 56, 1545–1551     

探索介尺度科学:从新角度审视老问题

本文介绍了国家自然科学基金委员会重大研究计划"多相反应中的介尺度机制及调控"的立项背景、聚焦的科学问题,以及该计划对化学工程的发展和介尺度科学的形成可能产生的影响.研究认为,介于分子/原子和宏观材料之间的物相或表界面结构及介于颗粒(气泡、液滴)和单元化工设备之间的非均匀结构是实现物质转化工艺过程定量设计、放大、优化和调控的瓶颈问题.这两个介尺度问题及其跨层次的关联是当代化学工程科学的核心,这些问题的解决将大大促进化学工程及相关学科由经验向量化过渡,并为逐步形成具有学科交叉特色的介尺度科学作出贡献.     

Promises and Problems of Mesoscale Materials Chemistry or Why Meso?

Manipulation and control of chemical structures on the mesoscale has recently developed to a very promising and also aesthetically appealing area of chemistry. This concept article tries to integrate the views of two experts to delineate the specific principles, approaches, and the novel opportunities for chemistry that arise from the rational control of matter and functionality on that scale.     

The Lanthanide Contraction beyond Coordination Chemistry

The lanthanide contraction is conceptualized traditionally through coordination chemistry. Here we break this mold in a structural study of lanthanide ions dissolved in an amphiphilic liquid. The lanthanide contraction perturbs the weak interactions between molecular aggregates that drive mesoscale assembly and emergent behavior. The weak interactions correlate with lanthanide ion transport properties, suggesting new strategies for rare‐earth separation that exploit forces outside of the coordination sphere.     

高卷曲高性能粘胶纤维工艺条件对性能的影响

利用棉绒浆粕和很少量的粘胶变性剂研制成高卷曲高性能粘胶纤维。研究了粘胶和纺丝工艺条件对纤维卷曲性、湿强度、湿模量等性能的影响。调节工艺条件,以高度的纺丝牵伸,得到纤维横截面成不对称的结构,从而获得高度的卷曲和好的性能。试验纤维同美国ITT公司生产的高卷曲高湿模量粘胶纤维比较,其卷曲数、卷曲稳定性、湿强度、湿伸长、湿模量和耐碱性均较高。     

不同环境条件对土壤-巴戟天系统重金属分布的影响

采用AA-6800型石墨炉原子吸收光谱仪研究了土壤-巴戟天系统中铅的分布情况,包括不同地段、不同土壤类型、不同土壤pH值对土壤-巴戟天入药部位根和果实中铅的含量影响。实验结果表明,环境条件变化对土壤-巴戟天系统铅含量有一定的影响,其中土壤的pH值对土壤中的有效铅浓度及巴戟天的铅含量影响较大。     

Microscopic structure and solvation in dry and wet octanol

Octanol-water partition coefficients are extraordinarily successful for correlating and predicting numerous processes of pharmacological and environmental importance. The amphiphilic nature of the 1-octanol molecules allows the octanol phase to mimic the complexities of many different environments ranging from biomembranes to soil. However, the structural details of the octanol phase and whether its structure is altered upon water saturation are not yet fully understood. Configurational-bias Monte Carlo simulations in the Gibbs ensemble demonstrate that a diverse spectrum of hydrogen-bonded aggregates exists in dry and wet 1-octanol, and that water saturation substantially alters the 1-octanol environment from predominantly linear aggregates in dry octanol to larger cylindrical micelles with water cores in wet octanol. These simulation results are able to reconcile the conflicting views (chain-like or water-centered aggregates vs spherical micelles) of the 1-octanol structure inferred from thermodynamic arguments, spectroscopic measurements, and diffraction experiments. Calculated partition constants quantify the influence of water saturation on the solubility characteristics of the dry and wet octanol phases.     

大孔吸附树脂分离提取多杀菌素

采用大孔吸附树脂法分离提取多杀菌素.从11种大孔吸附树脂中筛选出DM11进行了静态、动态吸附性能实验,并考察了不同吸附、解吸条件的影响.结果表明,DM11的静态吸附容量为25.63mg/g(wet resin),其吸附等温线符合Langmuir吸附等温式.采用丙酮做洗脱剂,洗脱率为97.5%,动态吸附最佳吸附pH为9.5,吸附流速为6BV/h,穿透吸附容量为21.2mg/ml(wet resin),洗脱流速1.5BV/h.     

A New Calibration Free pH‐Probe for In Situ Measurements of Soil pH

A new pH‐probe was developed for in situ determination of soil pH. It consists of a stainless steel tube with a plastic inset containing the indicator electrode, the reference electrode and a temperature sensor at the end of the tube. The indicator electrode is a quinhydrone composite electrode that does not need to be calibrated, because it acquires almost the theoretical predicted potential and has a constant formal potential and slope under all fabrication conditions. The pH‐probe has a low standard deviation (±4 mV or 0.07 pH units). The response time is short (5 s). To characterize its function the soil pH‐probe was used to analyse pond and arable soil samples. The results were compared with those obtained with a conventional combined glass electrode. To evaluate the results, measurements were performed (i) in natural wet soil samples (in situ conditions), (ii) after drying and moistening the soil samples (moistened samples) and (iii) after drying the soil samples and mixing with bidistilled water (soil solutions; generally accepted method in laboratories). The minimum water content required to obtain stable potentials in soil samples was 10%. The influence of S^2?, NO and Fe³⁺ as naturally available reducing and oxidising agents on the potential response of the pH‐probe was investigated. All the obtained results demonstrate that the developed pH‐probe is a powerful tool to measure the pH of a soil sample under in situ conditions without a calibration step.     

Macroporous oxide materials with three-dimensionally interconnected pores

Ordered mesoscale hollow spheres (1000 nm diameter) of binary oxides such as TiO₂ and ZrO₂ as well as of ternary oxides such as ferroelectric PbTiO₃ and Pb(ZrTi)O₃ have been prepared by templating against colloidal crystals of polystyrene, by adopting different procedures.     

Mesoscale Clusters in the Crystallisation of Organic Molecules

The early stages of the molecular self-assembly pathway leading to crystal nucleation have a significant influence on the properties and purity of organic materials. This mini review collates the work on organic mesoscale clusters and discusses their importance in nucleation processes, with a particular focus on their critical properties and susceptibility to sample treatment parameters. This is accomplished by a review of detection methods, including dynamic light scattering, nanoparticle tracking analysis, small angle X-ray scattering, and transmission electron microscopy. Considering the challenges associated with crystallisation of flexible and large-molecule active pharmaceutical ingredients, the dynamic nature of mesoscale clusters has the potential to expand the discovery of novel crystal forms. By collating literature on mesoscale clusters for organic molecules, a more comprehensive understanding of their role in nucleation will evolve and can guide further research efforts.     

A mesoscopic Archimedean tiling having a new complexity in an ABC star polymer

The Archimedean tiling (3².4.3.4) is a regular but complex polygonal assembly of equilateral triangles and squares. This tiling pattern with mesoscopic repeating distance has been found for an ABC star‐branched three‐component polymer composed of polyisoprene, polystyrene, and poly(2‐vinylpyridine). In this structure the environment of a molecule splits into multiple sites and two microdomains with different sizes and shapes are formed for one component. This complexity is the first observation in complex polymer systems and can lead to a new type of mesoscale self‐organization. The tiling pattern has been observed for the other materials on much shorter length‐scale; therefore, the experimental fact observed in the present study is demonstrating that the complexity is universal over different hierarchies. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2427–2432, 2005     

Mesotubular‐Structured Hybrid Membrane Nanocontainer for Periodical Monitoring,Separation, and Recovery of Cobalt Ions from Water

Exposure to toxins can cause deleterious effects even at very low concentrations. We have developed an optical sensor, filter, and extractor (i.e., containerlike) in a nanoscale membrane (NSM) for the ultratrace sensing, separation, and recovery of Co²⁺ ions from water. The design of the NSM is successfully controlled by dense decoration of a hydrophobic oil‐hydrophilic receptor onto mesoscale tubular‐structured silica nanochannels made of a hybrid anodic alumina membrane. The particular structure of the nanocontainer is ideal to control the multiple functions of the membrane, such as the optical detection/recognition, rejection/permeation, and recovery of Co²⁺ species in a single step. A typical sensor, filter, and extractor assessment experiment was performed by using a benchtop contact time technique and a flow‐through cell detector to allow for precise control of the optical detection and exclusive rejection of target ions and the permeation of nontarget metal ions in water. This nanocontainer membrane has great potential to meet the increasing needs of purification and separation of Co²⁺ ions.     

甲酰胺塑化热塑性淀粉的性能研究

用甲酰胺作为塑化剂制备了热塑性淀粉 (TPS) ,扫描电镜显示甲酰胺可以使淀粉塑化 ,形成均一的连续相 ;流变性能说明在加工温度范围内 ,甲酰胺塑化淀粉 (FPTPS)的剪切应力对温度变化敏感性要小于甘油塑化淀粉 (GPTPS) ;用热重和DSC研究了热稳定性和玻璃化转变 ;FPTPS在 13%～ 2 3%的水含量时有较好的力学性能 ,水含量为 13%时 ,FPTPS有最大的断裂强度 3 9MPa ;水含量为 17%时 ,FPTPS最大的伸长率为 95 % ;与GPTPS相比 ,在RH(Relativehumidity) =0 5 0 %and 10 0 %环境下 ,FPTPS有良好的耐回生性能 ,这主要是因为甲酰胺可以和淀粉羟基形成更稳定的氢键     

A review of the studies on environmental transport and speciation analysis of radionuclides in India

Department of Atomic Energy, India, has a systematic environmental monitoring program to ensure that the impact of radionuclides on human and environment is well within the limits, stipulated by the regulatory body. Concentrations of radionuclides are estimated in air, water, soil, sediment and biota in the environment around the power plant site on a regular basis. The environmental migration pattern and impact of radionuclides in the environment depends upon not only on the total concentration but the physico-chemical nature of radionuclide also. This paper presents a brief review of the studies of environmental transportation of radionuclides and influence of speciation with special reference to Indian conditions. A fairly good amount of results are available on the influence of speciation of radionuclides on the wet and dry deposition and preliminary results are available on the speciation analysis in dietary items, in soil and in ground water. Initial studies are concentrated on tritium, ¹³⁷Cs, Uranium, ⁹⁰Sr and their chemical analogues.     

临氢还原处理对Al2O3负载的CuO-MOx催化剂的影响

研究了Ｈ２预处理对Ａｌ２Ｏ３负载ＣｕＯ和ＣｕＯ－ＭＯｘ催化剂的作用。考察了Ｈ２处理时间、Ｈ２处理浓度以及多次还原氧化循环对ＣｕＯ系催化剂ＣＯ氧化活性的影响规律,并用原位还原氧化反应技术、ＸＰＳ对Ｈ２预处理的作用进行了研究。结果表明,ＣｕＯ－ＣｏＯ／Ａｌ２Ｏ３和ＣｕＯ－Ｃｅ２Ｏ３／Ａｌ２Ｏ３催化剂受Ｈ２还原处理后ＣＯ氧化活性明显增加,并随Ｈ２处理时间、处理浓度的增加而增强。而且催化剂的ＣＯ氧化活性还     

Factors affecting arsenic speciation in environmental samples: sample drying and storage

Arsenic is a ubiquitous element. Its toxicity, mobility, and bioaccumulation depend usually on its chemical form, and therefore, arsenic speciation is indispensable for the assessment of environmental risk and human hazard. Little is known about the effect of sample preparation procedures, such as drying and storage, on the resulting arsenic speciation. In this study, we investigated the influence of different drying methods and storage conditions on the arsenic speciation in mineral soils, organic soils, and plants. Drying soils and plants using different methods may change the concentrations of the total methanol–water (20%,?v/v) extractable arsenic, the proportion of organic arsenic and the ratio of arsenite-to-arsenate. Loss of methanol–water extractable arsenic compounds (up to 63%) was observed particularly in the samples rich in water. Following drying, the speciation of organic arsenic changed less than that of inorganic arsenic. Drying showed little influence on the total arsenic determination. None of the storage methods tested could preserve the arsenic speciation in organic soils and plants, although arsenic speciation after one-month storage varied less in freeze-dried samples than wet samples. Storage of the samples at low temperatures (2 or??20°C) had the largest impact on the samples rich in organic matters, leading to less arsenic being extractable by methanol–water. Both drying and storage of the soil and plant samples changed apparently the arsenic speciation. Therefore, we recommend conducting the arsenic speciation possibly with fresh and wet samples, so that the results of arsenic speciation may be more approaching the original states.     

湿天然气中乙烷氧化脱氢：添加水蒸气对催化剂活性和稳定性的影响

在Ｍｎ２Ｏ３／ＳｉＯ２催化剂上添加水蒸气对湿天然气中乙烷氧化脱氢的活性与稳定性进行了考察,结果表明：水蒸气量对催化剂活性影响不大,对催化剂上析炭有明显抑制作用。催化剂寿命实验连续运转２００ｈ,乙烯选择性仍保持在７５％,乙烯收率保持在４０％。催化剂上仅有轻微结炭,催化剂强度好无粉化现象。用比表面仪、ＸＰＳ和ＸＲＤ对实验前后的催化剂进行了对比分析。结果表明,催化剂具有良好的物相结构稳定性,因此具有较好的工业应用前景