Physicochemical Properties,Chemical Composition and Antioxidant Activity of <Emphasis Type="Italic">Dalbergia odorifera</Emphasis> T. Chen Seed Oil

The heartwood or root of Dalbergia odorifera T. Chen is an important traditional medicine in Asia. The aim of the present study was to evaluate the physicochemical properties, chemical composition and antioxidant activity of Dalbergia odorifera T. Chen seed oil. Oil, protein, carbohydrate, moisture, ash and total phenolic contents were found to be 12.96, 26.86, 42.58, 13.70, 3.90 and 5.55%, respectively. Free fatty acids, iodine number, peroxide value, saponification number and unsaponifiable matter were 1.66%, 106.53 g/100 g, 5.07 meq O₂/Kg, 196.78 mg KOH/g and 1.70%, respectively. The oil showed high absorbance in the UV-B and UV-C ranges with potential for use as a broad spectrum UV protectant. The major fatty acids were linoleic acid (60.03%), oleic acid (17.48%) and palmitic acid (16.72%). The total tocopherol, total phenolics and β-carotene were 511.9, 351.1 and 62.2 mg/kg oil, respectively. In addition, the methanol extract of seed oil showed significant in vitro antioxidant activity in four assays including DPPH radical scavenging activity, reducing power, linoleic acid peroxidation inhibition and chelating activity. This study suggests that Dalbergia odorifera T. Chen seed oil has the potential to be used in new products in the functional food, cosmetic or pharmaceutical industries.     

药对款冬花、紫菀及其单味药中挥发油的GC-MS分析

为比较款冬花与紫菀配伍前后挥发油成分的变化,采用水蒸气蒸馏分别对药对款冬花-紫菀及单味药挥发油进行了提取,并结合GC-MS-计算机检索技术对所得样品化学成分进行了分离和结构鉴定,用峰面积归一法测定各组分的相对质量分数。结果表明,从药对款冬花-紫菀、款冬花和紫菀挥发油分别鉴定了37、31和32个色谱峰,各占挥发油总峰面积的96.48%、88.47%和91.61%。药对产生4种新的化合物,而且它们共有成分配伍前后含量也有所改变。     

低温、低浊、低碱度水助凝效能试验研究

针对低温、低浊、低碱度水,以聚合氯化铝为絮凝剂,通过烧杯试验,确定了生石灰(CaO)、阴离子型聚丙烯酰胺(APAM)、活化硅酸(AS)单独助凝的最优条件,进一步考察了APAM、AS分别与CaO联用的助凝效果。研究结果表明:5种助凝剂均能起到一定的助凝作用,但APAM、AS分别与CaO联用的助凝效果不理想。滞后聚合氯化铝30 s投加0.3 mg/L APAM,浊度去除率可达88.1%;AS投加时间对有机物去除效果影响显著,延迟聚合氯化铝30~60 s投加时,对CODMn和TOC去除效果最好。兼顾除浊和除有机物,AS助凝效果最佳,是提高混凝沉淀工艺污染物去除率的有效途径之一。     

含磺酸基聚羧酸阻垢分散剂的合成与性能评价

以水为溶剂、过硫酸铵为引发剂,合成了甲基丙烯酰氨基二乙酸(MAIDA)、马来酸酐(MA)和甲基丙烯磺酸钠(SMS)三元共聚物.实验结果表明:当n(MA)∶n(MAIDA)∶n(SMS)=3∶1∶1时,共聚物具有很好的耐热性能;当其质量浓度为6 mg/L时,对碳酸钙阻垢率为96.3％;当其质量浓度为10 mg/L时,氧化铁透光率为58.3％,具有良好的分散性能.通过扫描电镜(SEM)观察了碳酸钙晶体形貌,探讨了共聚物致碳酸钙晶体发生畸变的防垢机理.     

化学反应工程学的教学实践与探索

本文探讨了化学反应工程学的知识层次,提出了两个层次教学的概念,强调了理论联系实际的重要性,探讨了化简分析拓广法解决问题的方法,并总结了教学实践过程中的经验.     

Cementing mechanism of potassium phosphate based magnesium phosphate cement

Magnesium phosphate cements (MPCs) are materials that belong to chemically bonded ceramic materials. They have a wide range of potential applications, due to their superior performance. In this paper, the reaction products and cementing mechanism of magnesium phosphate bonded cement based on the dead burned magnesia and the mono-potassium phosphate (MPP) are investigated. Fine powder and grains of dead burned magnesia were used to prepare pure cement paste and bonding cluster samples, respectively. The cement reaction products and their micro-morphology in the both different samples are examined. The microstructure of specimens is analyzed by SEM, TEM, XDR, and optical microscopy. Struvite of potassium (MgKPO₄·6H₂O) is observed in the reaction products. According to the analysis, it is found that struvite exists in both crystalline and amorphous form. There is also residual magnesia in the hardened cement paste. By means of microscopy observation, it can be seen that reaction products form around the unreacted magnesia and can develop into a continuum structure, which further produces the hardened paste. Struvite can grow up to form the more perfect crystal in a long term curing age, if large enough space is available during the hydration process.     

基于分片化MPCA模型的多阶段批次过程阶段分析与阶段辨识方法(英文)

Multi-way principal component analysis (MPCA) is the most widely utilized multivariate statistical process control method for batch processes. Previous research on MPCA has commonly agreed that it is not a suitable method for multiphase batch process analysis. In this paper, abundant phase information is revealed by way of partitioning MPCA model, and a new phase identification method based on global dynamic information is proposed. The application to injection molding shows that it is a feasible and effective method for multiphase batch process knowledge understanding, phase division and process monitoring.     

The possibility and applicability of coagulation-MBR hybrid system in reclamation of dairy wastewater

The significant improvements of membrane technology in reliability and cost effectiveness have increased the reuse probability and recycling extent of dairy wastewater. However, membrane fouling still remains a major bottleneck in wide application. In order to solve the problem, this paper investigated the possibility and applicability of coagulation-membrane bioreactor (MBR) hybrid system in reclaiming dairy wastewater. A comparative experiment based on the removal efficiencies and the membrane performance was designed to achieve the purpose. The results showed that polyaluminium chloride as the appropriate coagulant in coagulation process was effective for turbidity removal. Coagulation process played a very important role in stabilizing the effluent of MBR and the level of transmembrane pressure. MBR was a crucial process in turbidity and aluminum removal. MBR had the capability to resist shock loading and to maintain the high COD removal. Biological flocs in MBR could improve the fouling level of membrane. The hybrid system reduced 98% COD from the original and COD value of the wastewater came down to 8 mg/L. The combination of coagulation with MBR presents the possibility and applicability to reclaim effluent in dairy industries.     

Synthesis and thermoelectric performance of Li-doped NiO ceramics

Ni_1?xLi_xO (x = 0, 0.03, 0.06, 0.09) powders were prepared by sol–gel method combined with sintering procedure using Ni(CH₃COO)₂·4H₂O and citric acid as the raw materials and alcohol as solvent. The crystal structures of the samples were investigated by X-ray diffraction and Raman spectroscopy. The thermoelectric properties, such as the electrical conductivity, the Seebeck coefficient and the thermal conductivity were measured. The results showed that all the samples are p-type semiconductors. The electrical conductivity increases with the increase of the temperature, which indicates that the substitution of Li⁺ for Ni²⁺ can increase the concentrations and mobility of the carriers. The thermal conductivity decreases remarkably with the increase of the Li doping content, which indicates that Li doping can enhance the scattering of phonon. However, the Seebeck coefficient will decline with the increase of the Li doping content. As results of the increase of electrical conductivity and reduction of thermal conductivity, Li doping can increase the figure of merit (ZT) of NiO, the ZT value reach 0.049 at 770 K for Ni_1?xLi_xO with x = 0.06.     

Effect of TiO2 nanoparticles on the antibacterial and physical properties of polyethylene-based film

TiO₂ nanoparticles and their application in packaging systems have attracted a lot of attention because of its antimicrobial activity. In this work, effect of TiO₂ nanoparticles on the antibacterial and physical properties of polyethylene (PE)-based film was investigated. Results indicated that the antibacterial activity of TiO₂-incorporated PE films should be due to the killing effect property of TiO₂ nanoparticles against microorganisms. The TiO₂-incorporated PE film exhibited more effective antibacterial activity for Staphylococcus aureus. The antibacterial activity to inactivate Escherichia coli or S. aureus was improved by UV irradiation. The inhibition ratio of TiO₂-incorporated PE films sample irradiated for 60 min by UV light was improved significantly, which were 89.3% for E. coli and 95.2% for S. aureus, respectively, compared to that of TiO₂-PE film without UV irradiation. The analysis of physical properties revealed that TiO₂ nanoparticles increased the tensile strength and elongation at break of PE-based film. The climate resistance of nano-TiO₂ films is greatly enhanced, compared to that of the blank PE film. Water vapor transmission increased from 18.1 to 24.6 g/m²·24 h with the incorporation of TiO₂ nanoparticles. Results revealed that PE based film incorporating with TiO₂ nanoparticles have a good potential to be used as active food packaging system.