电感耦合等离子体原子发射光谱法测定工业电解质中钙、镁、锂

工业电解质中微量元素钙、镁、锂对电解槽的正常运行非常重要。本文采用高氯酸加热挥发除氟,以盐酸(1 1)溶解残渣,选用Ca317.9nm、Mg297.5nm、Li670.7nm作为分析谱线,考察了样品处理方法、共存元素干扰对测定结果的影响。建立了电感耦合等离子体原子发射光谱法测定工业电解质中钙、镁、锂的方法。结果表明：不同的电解质因其所含氧化铝的不同会有部分不溶杂质,但对微量元素的测定影响很小,可以忽略不计。共存元素铝和钠不干扰微量元素的测定。按照试验方法对2个电解质标准样品进行了测定,其测定值与标准值吻合。同时对不同电解槽的工业电解质样品进行了分析,其结果的相对标准偏差(RSD,n=11)在0.69%-5.68%之间,满足生产分析的需要。     

通讯作者：于冀芳,石家庄市鹿泉区上庄大街河北省质检中心,050000, 18032188277,

采用微波消解技术对工业锅炉用水进行前处理,建立了微波消解-电感耦合等离子体发射光谱法(ICP-AES)测定工业锅炉用水中钙、镁、铁、铜含量的分析方法。分别对样品的微波消解温度和保持时间进行讨论,优化了微波消解前处理技术。结果表明：给水在消解温度为170 ℃,保持时间为10 min条件下,回水在消解温度为180 ℃,保持时间为12 min条件下,锅炉水在消解温度为185 ℃,保持时间为15 min条件下,微波消解最理想。应用本方法对锅炉用水中钙、镁、铁、铜进行测定,线性范围均为0～2.0 mg/L,检出限分别为0.002 mg/L、0.002 mg/L、0.003 mg/L、0.004 mg/L,回收率为95%～103%,相对标准偏差RSD(n=7)均小于9.32%,与原子吸收法(AAS)进行比较,测定结果基本一致。     

Life sciences and materials: A successful marriage is possible

Although some companies are separating their life sciences and materials businesses, others are keeping these entities under the same corporate umbrella to take advantage of possible synergies at the biology/materials science interface. The following remarks, which provide some perspectives about DuPont's approach to this strategy, were delivered as a keynote address at a conference titled “Life Sciences and Materials … Successful Marriage or Divorce?” organized in Pisa, Italy, in October 1999, by the European Polymer Federation and the University of Pisa. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 667–678, 2000     

A Fault-Tolerant Transmission Scheme in SDN-Based Industrial IoT (IIoT) over Fiber-Wireless Networks

Driven by the emerging mission-critical and data-intensive applications in industrial intelligent manufacturing, the software-defined network (SDN) based fiber-wireless access network (FiWi) is attracting considerable attention thanks to its capability of central control and large bandwidth. However, the heterogeneity of the network leads to new challenges, since the packet loss can be caused either by the poor channel quality of wireless links or network component failures. A novel and adaptive mechanism combining sparse random linear network coding with parallel transmission (SNC-PT) is proposed to achieve the fault-tolerance against high packet loss rate and any network element malfunction. We illustrate the benefits of using the SNC-PT mechanism to improve fault tolerance by characterizing the network performance with respect to the completion time and goodput along with its relationship to channel quality and node failures. We show that significant performance gains can be obtained in comparison with conventional uncoded transmission based on transmission control protocol (TCP). The simulation results show that the SNC-PT mechanism is fault-tolerant, while it can significantly shorten the data transmission completion time to at least 12% of the baseline and increase the goodput by about 10% compared to other coding schemes such as random linear network coding.     

代数重建技术在板壳结构断层重建中的应用

针对板壳结构用锥束射线倾斜扫描时数据缺失等问题,利用代数重建技术(ART)进行了断层重建。计算机模拟结果表明,由ART重建出的切片图像质量远好于先前用滤波反投影(FBP)重建出的切片图像质量。对影响ART算法的各种因素进行了调整,即选取适当的初始图像和收敛因子就可获得最佳的图像质量。     

Antioxidant,Antimicrobial Activities and Fatty Acid Compositions of Wild Berberis spp. by Different Techniques Combined with Chemometrics (PCA and HCA)

Interest in medicinal plants and fruits has increased in recent years due to people beginning to consume natural foods. This study aims to investigate the total phenolic flavonoid content, antioxidant activity, condensed tannin content, oil content, and fatty acid compositions of five local breeds of Berberis spp. from Bayburt, Turkey, and their antioxidant and antimicrobial activities. The fatty acid composition of samples was performed with gas chromatography-mass spectrometry (GC-MS), and the total fatty acid content of samples was between 6.12% and 8.60%. The main fatty acids in Berberis spp. samples were α-linolenic acid (32.85–37.88%) and linoleic acid (30.98–34.28%) followed by oleic acid (12.85–19.56%). Two antioxidant assays produced similar results, demonstrating that extracts of wild B. vulgaris L. had the highest ferric reducing antioxidant power (FRAP) (621.02 μmol FeSO₄.7H₂O/g) and 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) (0.10 SC₅₀ mg/mL) values. According to principal component analysis (PCA), four components were determined. In addition, two main groups were determined according to hierarchical cluster analysis (HCA), and wild and culture of B. vulgaris L. were in different subgroups. This is the first original report about the fatty acid composition and oil content of Berberis spp. grown in Bayburt, Turkey. The obtained results indicate that B. integerrima Bunge and B. vulgaris, which have especially remarkable fatty acid content, antioxidant, and antimicrobial activity, could be potential sources for these properties in different areas of use.     

The Nutritional and Antioxidant Potential of Artisanal and Industrial Apple Vinegars and Their Ability to Inhibit Key Enzymes Related to Type 2 Diabetes In Vitro

The main objective of the current study was to determine the physicochemical properties, antioxidant activities, and α-glucosidase and α-amylase inhibition of apple vinegar produced by artisanal and industrial methods. Apple vinegar samples were analyzed to identify their electrical conductivity, pH, titratable acidity, total dry matter, Brix, density, mineral elements, polyphenols, flavonoids, and vitamin C. The antioxidant activity of apple vinegar samples was evaluated using two tests, total antioxidant capacity (TAC) and DPPH radical scavenging activity. Finally, we determined α-glucosidase and α-amylase inhibitory activities of artisanal and industrial apple vinegar. The results showed the following values: pH (3.69–3.19); electrical conductivity (2.81–2.79 mS/cm); titratable acidity (3.6–5.4); ash (4.61–2.90); °Brix (6.37–5.2); density (1.02476–1.02012), respectively, for artisanal apple vinegar and industrial apple vinegar. Concerning mineral elements, potassium was the most predominant element followed by sodium, magnesium, and calcium. Concerning bioactive compounds (polyphenols, flavonoids, and vitamin C), the apple vinegar produced by the artisanal method was the richest sample in terms of bioactive compounds and had the highest α-glucosidase and α-amylase inhibition. The findings of this study showed that the quality and biological activities of artisanal apple vinegar were more important than industrial apple vinegar.     

固定床F-T合成Fe-Cu-K催化剂3000小时模试

进行了两段法Ｆ－Ｔ合成（ＭＦＴ）Ｆｅ－Ｃｕ－Ｋ催化剂３０００小时模试工艺改进后的适应性,催化剂性及共影响因素,结果表明,ＣＯ转化率达到了７５～８５％,烃选择性达７８～９４％,Ｃ６＾＋产率达８５～１００ｇ／ＮＭ＾３（ＣＯ＋Ｈ２）。     

代谢工程研究进展

介绍了近几年代谢工程在降解氟氯烃等环境污染物、生产古龙酸、抗生素、丙二醇、聚羟基链烷酸及紫杉醇等重要化合物和中间体、木糖等生物质再生资源的利用、工业发酵及植物改良方面的最新进展以及基本的设计思想。