原子荧光紧密内插法快速测定莲藕中砷的生物吸收比

目的 为建立一种快速测定莲藕中微量砷和生物吸收比的新型原子荧光法。方法 用微波辅助消解样品,用紧密内插法测定莲藕各组织和土壤中的砷。结果 结果表明：藕肉和藕节中砷的质量分数较小,藕皮和藕尖中砷的质量分数较大。各组织砷的生物吸收比为79.54%-22.03%,与国标法相比,通过显著性检验,方法之间没有显著性差异,结论的置信度为95%。结论 该法不需要绘制标准曲线和测定空白,快速简便,计算简单,具有一定的创新性和推广应用价值。     

Simulation and analysis of dual-reflux pressure swing adsorption using silica gel for blue coal gas initial separation

A dual-reflux pressure swing adsorption (DR-PSA) process was proposed and simulated to initially separate the blue coal gas, aiming to capture carbon dioxide (CO₂) and enrich hydrogen (H₂), simultaneously. With a feed flow rate of 7.290 slpm, a light product reflux flow rate of 0.505 slpm and the heavy product reflux flow rate of 3.68 slpm, the developed DR-PSA process could capture CO₂ up to 64.01% with a recovery of 99.60% and enrich H₂ up to 34.66% with a recovery of 97.63% from the blue coal gas (36.2% N₂/28.5% H₂/13.9% CO/12.7% CO₂/8.7% CH₄). In addition, in order to optimize the process, the effects of various operating parameters on the DR-PSA process performance in terms of product purity and recovery were discussed in detail, including the feed position, the light product reflux ratio and the heavy product reflux ratio. Moreover, the dynamic distribution behaviors of pressure, temperature and gas-solid concentration were presented to explain and evaluate the process separation performance in depth under different operating conditions.     

2011～2020年华北平原气溶胶光学厚度时空分布特征及潜在源分析

随着经济高速增长和城市化进程不断加快,华北平原区域性空气污染问题愈演愈烈。针对该区域开展长时序气溶胶光学厚度时空分布特征和潜在源分析研究,对华北平原大气污染治理具有重要意义。基于长时序MODIS/Terra C6.1 MOD04_L2气溶胶光学厚度产品,分析华北平原气溶胶光学厚度的时空分布特征,并利用后向轨迹聚类分析讨论华北平原7个重点城市气团输送的季节变化,并以污染较为严重的河北石家庄为例进行潜在源分析和浓度权重分析,探究影响其大气质量的污染物潜在源区。结果表明:2011～2020年华北平原气溶胶光学厚度月均值呈显著的周期性变化,以年为周期,每个周期内峰值一般出现在6月至8月; 气溶胶光学厚度月际年内呈单峰分布,峰值出现在6月(0.75),最小值出现在12月(0.37); 气溶胶光学厚度季均值从大到小依次为夏季(0.67)、春季(0.59)、冬季(0.49)、秋季(0.46); 10年间气溶胶光学厚度呈下降趋势,整体下降幅度达36.84%,其中2011年最高(0.72),2018年最低(0.45); 华北平原7个重点城市春、夏、秋、冬四季主要受短距离气团输送影响较大,长距离气团输送影响较小; 2014～2020年河北石家庄的空气质量优良天数占比相对较小,空气质量状况差,影响其空气质量的污染物多为本地生成,同时也受周边省市近距离输送的影响。     

黑豆糖蛋白的结构分析及抗氧化和免疫活性

本实验从黑豆中分离得到两种糖蛋白，并对其结构组成、抗氧化活性和免疫活性进行研究，为糖蛋白的高效开发利用提供理论依据。采用碱提醇沉法提取黑豆糖蛋白粗品，命名为HDJ，通过DEAE-52纤维素柱层析和Sephadex G-100柱层析分离纯化获得两个均一组分，分别命名为HDJS2和HDJS5-2。利用物理化学方法和光谱法对其化学组成及结构进行分析，通过测定总还原力、1,1-二苯基-2-三硝基苯肼（2,2-diphenyl-1-picrylhydrazyl，DPPH）清除率及总抗氧化能力研究两种糖蛋白的抗氧化活性，采用噻唑蓝比色法评价两种糖蛋白的免疫活性。结果表明：HDJS2（3.20×104 Da）和HDJS5-2（3.89×104 Da）主要是由中性糖和蛋白质组成的糖蛋白，其糖肽键类型均为O-型糖肽键。HDJS2主要由甘露糖、葡萄糖、半乳糖、阿拉伯糖、岩藻糖和96.1%氨基酸组成；HDJS5-2主要由甘露糖、葡萄糖、半乳糖、阿拉伯糖和71.3%氨基酸组成。抗氧化分析结果表明，HDJS2和HDJS5-2的还原能力、DPPH清除能力和抗氧化能力呈剂量依赖性关系。此外，HDJS2和HDJS5-2均能够促进脾淋巴细胞增殖。结论：HDJS2和HDJS5-2具有潜在的抗氧化作用和免疫调节作用。     

Electronic transport properties of phosphorene/graphene(silicene/germanene) bilayer heterostructures: A first-principles exploration

Recently, new researches on van der Waals (vdW) two-dimensional bilayer heterostructures have been carried out owing to their unique properties different from single-layer materials. Herein, three types of bilayer heterostructures, phosphorene/graphene, phosphorene/silicene and phosphorene/germanene are constructed and their electronic transport properties are calculated based on the first-principle method. The results show that their I-V curves are totally different that the phosphorene/graphene devices have higher electron transmission probability, resulting in higher current values. Furthermore, we calculate their band structures to explore the internal mechanism of current difference. The graphene-like Dirac cones are found in the bilayer phosphorene/graphene heterostructures. However, the positions of their Dirac cones in the Brillouin zone are markedly different from that of graphene. But when the silicene or germanene is combined with the phosphorene together, the Dirac cones of the silicene or germanene disappear, instead, there are band gaps of about 0.2?eV around the Fermi level. Our results suggest that the Dirac cone can be mainly retained by the weak hybridization between monolayer phosphorus and 2D Dirac materials. Due to the existence of the Dirac cone, the overlap between the source and drain electrodes increases, which leads to a larger current value. This discovery of the Dirac cones in the bilayer heterostructures is applicable in designing Dirac materials and understanding their electronic transport properties.     

A spectroscopic method for quick evaluation of tint strength and tint tone of titania (rutile) pigment and factors affecting them

Titanium dioxide (TiO₂) manufacturing industries measure optical properties such as brightness, colour, tint strength, tint tone, gloss, scatter coefficient, and others to ensure the quality of the product. Product characterization and process control generally focus on the optical properties, which determine its quality. In this work, titania rutile pigment with varying tint strength and tint tone is analyzed and a correlation is established between particle size and the optical properties such as tint strength and tint tone. It is observed that optical properties of titania pigment depends on the particle size as well as particle size distribution. A relatively faster evaluation of tint strength and tint tone can be made using the reflectance and particle size measurements. Analytical samples were prepared by ultrasonic dispersion of pigment in water containing calgon as dispersing agent. To verify the accuracy of the method, pigment tint strength and tint tone obtained from this study are compared with those resulting from traditional analysis. The results showed that the new method is viable.     

Preparation and characterisation of a novel copper‐imprinted polymer based on β‐cyclodextrin copolymers for selective determination of Cu2+ ions

A novel ion‐imprinted polymer (IIP) using (6‐O‐butene diacid ester)‐β‐cyclodextrin (β‐CD‐MAH) as the functional monomer and copper ions as the template was developed for Cu²⁺ sensing. First, reactive β‐cyclodextrin (β‐CD) monomers with vinyl carboxylic acid functional groups were synthesised and were co‐polymerised with styrene via radical polymerisation. Then, the β‐CD copolymers were complexed with Cu²⁺ in order to obtain the IIP. The imprinting effect was realised by removing the template ions from the imprinted polymer. The structure, composition and morphology of the IIP were characterised by Fourier transform IR spectroscopy, energy‐dispersive spectroscopy and field‐emission SEM. The adsorption capacity was investigated by UV–visible spectroscopy in batch operation mode. The maximum adsorption capacity for the Cu²⁺ template ions was 28.91 mg g^?1, and the adsorption selectivity was clearly illustrated from the increased sorption affinity towards Cu²⁺ ions over other competing ions. The adsorption was affected by the pH of the aqueous medium, and enhanced adsorption capacity was observed at pH 5. The prepared IIP could be used 10 times after its regeneration without significant loss of the adsorption capacity. © 2018 Society of Chemical Industry     

水法合成扑草净原药废水综合治理工艺研究

扑草净原药生产中水为反应介质,存在废水量大,废水中污染物成分复杂,污染环境。经预处理,离子交换吸附后降低各项污染指标,基本能达标排放,特别是扑灭津,扑草净,COD值都有大幅度下降。     

Mesoporous electroactive silver doped calcium borosilicates: Structural,antibacterial and myogenic potential relationship of improved bio-ceramics

In this work improved electroactive mesoporous Ag-doped bio-ceramics for medical usages are developed, examining their structural, electrical, in-vitro bioactivity, cell cultures and antibacterial properties against various classical pathogenic bacteria. Ag-containing mesoporous bio-ceramics (MBCs): xmol%Ag₂O - (100-x)[45.8CaO-8.4B₂O₃-45.8SiO₂] where x = 2, 5, 7.5 and 10 were synthesized through a sol-gel method. The small angle X-ray scattering and electron microscopy studies reveal the embedment of silver nanoparticles in the samples. Existence of silver as Ag⁺/Ag⁰ forms in the samples is confirmed by X-ray photoelectron spectroscopy. The N₂ adsorption-desorption analysis evidence the mesoporous structure of the samples. The electrical conductivity of samples increases from 5.4 x 10^?8 S cm^?1 for x = 2 to 1.9 x 10^?6 S cm^?1 for x = 7.5 and then decreases to 0.9 x 10^?6 S cm^?1 for x = 10 at 110 °C. In vitro bioactivity studies revealed that Ag-containing MBCs hold the bone-like hydroxyapatite formation after immersion in human blood plasma like-solution such as Dulbecco's Modi?ed Eagle's Medium. The antibacterial effect of samples against pathogenic bacteria (S. aureus, E. coli, P. monas aeruginosa, and B. cereus) increases with Ag concentration (x = 7.5) and then decreases with Ag content (x = 10). Antibacterial effect is greater for the sample with high electrical conductivity. The cell culture studies evidence not considerable cytotoxic effects for Ag-containing MBCs. Finally, the C2C12 myoblast cell culture studies reveal the significant cell growths and differentiation (myogenesis) for high electrical conducting Ag-containing MBCs.