臭氧氧化-循环喷淋法处理钨钼选矿废水

采用臭氧氧化-循环喷淋法去除钨钼选矿废水中COD,研究了pH值、臭氧流量、循环频率对COD去除效果的影响。结果表明: 废水COD去除率随pH值、臭氧流量、循环频率增大而增加,在pH值为10、臭氧流量3.0 L/min、循环频率4.0次/min条件下,氧化120 min后废水COD含量由131 mg/L降至11.5 mg/L,COD去除率达91.2%,满足《污水综合排放标准》(GB 8978-1996)一级标准。与O₂、NaClO处理废水COD的对比试验结果表明,循环喷淋法结合O₃表现出较好的COD去除效果。     

Associations between Oil Yield and Profile of Fatty Acids,Sterols, Squalene,Carotenoids, and Tocopherols in Seed Oil of Selected Japanese Quince Genotypes during Fruit Development

Tocopherols, phytosterols, carotenoids, and squalene are present in mature seeds of Japanese quince. Yet, little is known about the relationship between these compounds and oil yield during fruit and seed development. The profile change of lipophilic compounds during fruit and seed development in Japanese quince cultivars “Darius,” “Rondo,” and “Rasa” is investigated. It is shown here that during fruit and seed development, there is a significant reduction, three‐ to over tenfold, in the concentration of minor bioactive compounds in seed oil. It is recorded that delay between synthesis of tocopherols and oil in Japanese quince seeds during the fruit development results in a logarithmic relationship between the oil content and tocopherols concentration in the seed oil (R² = 0.980). Similar trends are observed between oil yield and phytosterols, and carotenoids (R² = 0.927 and R² = 0.959, respectively). The profile of fatty acids during the development of the seeds significantly is changed. The reduction of linoleic, palmitic, and gondoic acids levels and increment of oleic acid is noted. The oil content, profile of fatty acids, and concentration of bioactive compounds in all three genotypes of Japanese quince do not change significantly statistically during the last month of fruit development. Practical Applications: Some fruits are harvested at different degrees of maturity mainly due to a logistic issue and uneven ripening of fruits, which affects the chemical composition of whole fruit including seeds. Therefore, it would be good to know how the chemical composition is changing in plant material during development especially in the last month before harvest. Production of Japanese quince continues to rise year to year and with it the volume of generated by‐products such as seeds. This study demonstrates how it changes the oil content, profile of fatty acid, and concentration of tocopherols, squalene, phytosterols, and carotenoids in the seeds and seed oil of three Japanese quince cultivars “Rondo,” “Darius,” and “Rasa” during plant development. The provided information can be very useful for the manufactories oriented on the processing of by‐products, mainly seeds, generated by other branches of industry, for instance, fruit‐processing.     

纳米Co/rGO磁性复合吸附材料的制备及对Cu2+的吸附性能

以改进Hummer法制备的薄片状氧化石墨烯(GO)为载体和模板负载钴离子，然后采用原位还原法制得纳米金属Co/石墨烯磁性复合吸附材料(Co/rGO)，并将其应用于对Cu2+的吸附和脱除，以期为高效可复用的铜离子脱除剂的合成与应用提供指导。实验结果证实，Co/rGO复合材料具有超顺磁性，能够很方便的使用磁铁进行分离并在无磁场情况下振荡分散。Co/rGO复合材料对Cu2+具有稳定的吸附/脱附性能，实验条件下对Cu2+的最大吸附容量达到117.5 mg/g且5 min内实现吸附平衡，远优于其原料GO的60 min吸附容量27.6 mg/g。本工作系统考察了NaOH加入量、络合剂种类、溶剂种类等关键因素对Co粒子在rGO载体上形貌和分布特性的影响，比较了不同合成条件下的复合材料对Cu2+吸附效果的影响，并对优选条件下制备的Co/rGO复合材料进行了FT-IR, XRD, SEM表征。研究结果表明，纳米Co/rGO磁性材料对Cu2+的吸附过程更符合Freundlich模型，属于多层吸附。室温下吸附焓ΔH=17.81 kJ/mol，吸附反应平衡常数Kθ=3.65。当初始Cu2+浓度为39.22 mg/L时，对Cu2+的吸附率为93.47%，五次吸附/脱附循环后吸附容量仍保持在初始值的94%，每次吸附后溶液中残余Cu2+浓度均满足钴电解液对杂质铜离子的浓度去除要求(5 mg/L)或GB 8978-1996污水综合排放标准3级(2 mg/L)，有望在相关领域发挥作用。     

Matrilin-3-Primed Adipose-Derived Mesenchymal Stromal Cell Spheroids Prevent Mesenchymal Stromal-Cell-Derived Chondrocyte Hypertrophy

Adipose-derived mesenchymal stromal cells (Ad-MSCs) are a promising tool for articular cartilage repair and regeneration. However, the terminal hypertrophic differentiation of Ad-MSC-derived cartilage is a critical barrier during hyaline cartilage regeneration. In this study, we investigated the role of matrilin-3 in preventing Ad-MSC-derived chondrocyte hypertrophy in vitro and in an osteoarthritis (OA) destabilization of the medial meniscus (DMM) model. Methacrylated hyaluron (MAHA) (1%) was used to encapsulate and make scaffolds containing Ad-MSCs and matrilin-3. Subsequently, the encapsulated cells in the scaffolds were differentiated in chondrogenic medium (TGF-β, 1–14 days) and thyroid hormone hypertrophic medium (T3, 15–28 days). The presence of matrilin-3 with Ad-MSCs in the MAHA scaffold significantly increased the chondrogenic marker and decreased the hypertrophy marker mRNA and protein expression. Furthermore, matrilin-3 significantly modified the expression of TGF-β2, BMP-2, and BMP-4. Next, we prepared the OA model and transplanted Ad-MSCs primed with matrilin-3, either as a single-cell suspension or in spheroid form. Safranin-O staining and the OA score suggested that the regenerated cartilage morphology in the matrilin-3-primed Ad-MSC spheroids was similar to the positive control. Furthermore, matrilin-3-primed Ad-MSC spheroids prevented subchondral bone sclerosis in the mouse model. Here, we show that matrilin-3 plays a major role in modulating Ad-MSCs’ therapeutic effect on cartilage regeneration and hypertrophy suppression.     

基于太赫兹光谱的人参和西洋参鉴别

为了快速区分人参和西洋参，依据两者所含的人参皂苷在太赫兹波段具有不同指纹光谱，提出了一种基于人参皂苷的太赫兹光谱鉴别人参和西洋参的方法。采用MATLAB软件识别人参和西洋参的太赫兹光谱，同时根据太赫兹光谱特征并通过标准的主成分分析(PCA)区分出人参、西洋参。实验结果表明，基于太赫兹光谱的主成分分析可精确区分出人参、西洋参，并且还可以应用于其他类似物质的区分中。     

Influence of particle contact models on soil response of poorly graded sand during cavity expansion in discrete element simulation

The discrete element method (DEM) has been extensively adopted to investigate many complex geotechnical related problems due to its capability to incorporate the discontinuous nature of granular materials. In particular, when simulating large deformations or distortion of soil (e.g. cavity expansion), DEM can be very effective as other numerical solutions may experience convergence problems. Cavity expansion theory has widespread applications in geotechnical engineering, particularly to the problems concerning in situ testing, pile installation and so forth. In addition, the behaviour of geomaterials in a macro-level is utterly determined by microscopic properties, highlighting the importance of contact models. Despite the fact that there are numerous contact models proposed to mimic the realistic behaviour of granular materials, there are lack of studies on the effects of these contact models on the soil response. Hence, in this study, a series of three-dimensional numerical simulations with different contact constitutive models was conducted to simulate the response of sandy soils during cylindrical cavity expansion. In this numerical investigation, three contact models, i.e. linear contact model, rolling resistance contact model, and Hertz contact model, are considered. It should be noted that the former two models are linear based models, providing linearly elastic and frictional plasticity behaviours, whereas the latter one consists of nonlinear formulation based on an approximation of the theory of Mindlin and Deresiewicz. To examine the effects of these contact models, several cylindrical cavities were created and expanded gradually from an initial radius of 0.055 m to a final radius of 0.1 m. The numerical predictions confirm that the calibrated contact models produced similar results regarding the variations of cavity pressure, radial stress, deviatoric stress, volumetric strain, as well as the soil radial displacement. However, the linear contact model may result in inaccurate predictions when highly angular soil particles are involved. In addition, considering the excessive soil displacement induced by the pile installation (i.e. cavity expansion), a minimum distance of 11a (a is the cavity radius) is recommend for practicing engineers to avoid the potential damages to the existing piles and adjacent structures.