双酰肼类蜕皮促进剂对水稻二化螟的触杀与内吸作用比较

采用点滴法和盆栽土壤处理法分别测定了双酰肼类杀虫荆虫酰肼、JS118和抑食肼(RH5849)对二化螟的触杀与内吸作用，并与氟虫腈和杀虫单进行了比较。结果表明，虫酰肼和JS118对二化螟4龄幼虫的触杀毒力相当，LD50分别为0．0252、0．0310μg／头，约是氟虫腈的十分之一、杀虫单的11～13倍；抑食肼的触杀毒力(LD50为0．2720μg／头)约是虫酰肼和JS118的十分之一。然而，抑食肼20、40ga．i．／667m^2处理盆栽土壤后3、7d，对二化螟、蚁螟的内吸杀虫效果分别迭66．9％～89．0％和84．4％～96．7％，与氟虫腈(2ga．i．／667m^2)、杀虫单(40ga．i．／667m^2)接近或相当，而虫酰肼和JS118(5、10ga.i．／667m^2)无明显内吸杀虫作用。     

弹性纳米粒子/纳米TiO2/聚丙烯复合材料的研究

采用专利技术制备了弹性纳米粒子(ENP)／纳米二氧化钛(TiO2)复合材料，并使用这种复合材料改性聚丙烯(PP)，制备了具有较高韧性和较好灭菌性能的PP纳米复合材料。当丁苯ENP的用量为2％，平均粒径为50nm的金红石型TiO2用量为1％时，所研制的PP纳米复合材料的冲击强度可提高30％以上，灭菌率可达60％。     

中压汽包法兰断裂失效原因分析及改进措施

本文针对中压汽包法兰断裂失效原因进行分析，指出汽包上两个法兰同时断裂的原因在于安全阀排汽管路设计上的失误，并提出对安全阀排汽系统的改进措施。     

FDI攻击下非线性多智能体系统分布式无模型自适应控制

为研究受到虚假数据注入攻击的单输入单输出非线性多智能体系统的分布式无模型自适应控制问题,提出了一种新的分布式动态线性化方法, 以获得非线性多智能体的等效线性数据模型。与现有多智能体的分布式无模型自适应控制在控制器设计中有所不同, 本文设计的控制器不需要网络拓扑结构的信息, 仅使用系统的输入输出数据。仿真算例验证了所提出的分布式无模型自适应控制算法可以实现多智能体系统的均方有界趋同控制。算法保证了多智能体系统在受到网络攻击时可以实现趋同控制目标。     

Mesoporous nanocrystalline zirconium oxide: novel preparation and photoluminescence property

A novel strategy involving the combination of soft-templating and solid–liquid method (CSSL) is presented to synthesize mesoporous nanocrystalline zirconia with high specific surface area, that is, the mesostructured zirconia hybrid is firstly synthesized via cooperative assembly between zirconium sulphate as inorganic precursor and 1-hexadecyl-3-methylimidazolium bromide (C₁₆mim⁺Br⁻) as the structure-directing agent, and subsequently ground with solid magnesium nitrate salt followed by heat-treatment in air. The resulting zirconia material after calcination at 600 °C possesses a wormlike arrangement of mesopores surrounded by tetragonal ZrO₂ nanocrystallites of ca. 2.3 nm. The BET surface area is 255 m²/g and the pore size is ca. 4.3 nm. However, no mesoporous structure exists in the obtained zirconia material via the simple soft-templating method at the same calcination temperature. Photoluminescence (PL) spectra of the obtained mesoporous nanocrystalline ZrO₂ show a strong emission peak at ca. 394 nm under UV excitation of 250 nm wavelength.     

Studies of a high temperature proton exchange membrane based on incorporating an ionic liquid cation 1-butyl-3-methylimidazolium into a Nafion matrix

High temperature proton exchange membranes based on Nafion were prepared by incorporating the polymer with ionic liquid cation 1-butyl-3-methylimidazolium (BMIm) and doping with phosphoric acid (PA). We found that using the hydroxide form rather than the chloride form of BMIm incorporated more readily the BMIm cation into Nafion film. A mole ratio of about 2 of BMIm cation to Nafion repeat unit, i.e., λ_BMIm/Nafion, was reached with the hydroxide form BMIm. The incorporated BMIm cation enhanced the doping of phosphoric acid into Nafion. A proton conductivity of 10.9 mS cm⁻¹ and a tensile stress at break of 5.3 MPa were achieved, respectively, with a composite membrane of Nafion/2.3BMIm/5.2PA in molar ratio at 160 °C without humidification.     

Composition and Thermal Analysis of Lipids from Pre-fried Chicken Nuggets

Composition and thermal profiles of the endogenous lipids of ten commercial chicken nuggets brands (NPO, ACO, AFO, APO, ASO, AMO, ARO, JOD, SMO, and SOD) were compared with those of the lipids of chicken nuggets pre-fried in lard (ALD) and palm olein (AOO) to determine the type of oil used for pre-frying of the product. The stearic acid content of the commercial brands were similar to that of the sample pre-fried in palm olein, but significantly (p < 0.05) lower than that of the sample pre-fried in lard. The triacylglycerol (TAG) profiles of the commercial brands were similar to that of the sample pre-fried in palm olein, but distinctly different from the sample pre-fried in lard according to the dissimilarities in the contents of TAG molecules namely, PLL, POS, and PPO. Based on thermal analysis, the commercial brands of chicken nuggets could be divided into three distinguishable subgroups namely, Group-A: NPO; Group-B: ACO, AFO, APO, ASO; Group-C: AMO, ARO, JOD, SMO, SOD. While brands under group-B showed close similarity to AOO, none show any similarity to sample ALD. As any of the samples did not possess characteristics of the sample pre-fried in lard, the commercial brands of chicken nuggets of this study are recommendable for consumers whose religious restriction prevents the use of lard in food.     

Analysis of Lard’s Aroma by an Electronic Nose for Rapid <Emphasis Type=Italic>Halal</Emphasis> Authentication

An electronic nose was successfully used to detect and discriminate lard from other types of animal body fats and samples containing lard. The results are presented in the form of VaporPrint™, the image of the polar plot of the odor amplitudes from the surface acoustic wave (SAW) detector frequency. In the VaporPrint™, the radial angles representing the sensor provides individual fingerprints of the aroma of different animal body fats. Principal component analysis (PCA) was used to interpret the data and it provided a good grouping of samples, with 61% of the variation accounted for by PC 1 and 29% accounted for by PC 2. All of the lard-containing samples formed a separate group from the samples that were free from lard. This method can be developed into a rapid method for detecting the presence of lard in food samples for Halal authentication.     

Response Surface Modeling of Processing Parameters for the Preparation of Phytosterol Nanodispersions Using an Emulsification–Evaporation Technique

The purpose of this study was to optimize the production parameters for water-soluble phytosterol nanodispersions. Response surface methodology (RSM) was employed to model and optimize three of the processing parameters: mixing time (t) by conventional homogenizer (1–20 min), mixing speed (v) by conventional homogenizer (1,000–9,000 rpm) and homogenization pressure (P) by high-pressure homogenizer (0.1–80 MPa). All responses [i.e., mean particle size (PS), polydispersity index (PDI) and phytosterols concentration (Phyto, mg/l)] fitted well to a reduced quadratic model by multiple regressions after manual elimination. For PS, PDI and Phyto, the coefficients of determination (R ²) were 0.9902, 0.9065 and 0.8878, respectively. The optimized processing parameters were 15.25 min mixing time, 7,000 rpm mixing speed and homogenization pressure 42.4 MPa. In the produced nanodispersions, the corresponding responses for the optimized preparation conditions were a PS of 52 nm, PDI of 0.3390 and a Phyto of 336 mg/l.     

Effect of isotacticity distribution on crystallization kinetics of polypropylene

The crystallization kinetics of isotactic polypropylene (iPP) depends not only on the undercooling but also on its microstructure characteristics. In this paper the effect of isotacticity distribution on the isothermal kinetics of iPPs in the crystallization regime III was examined by differential scanning calorimetry. The microstructure features of two commercial film grade iPPs were characterized with temperature rising elution fractionation and size exclusion chromatography. The results indicated that, although the overall isotacticities and molecular weights of two iPPs were similar, their isothermal crystallization kinetics displayed marked differences due to the disparity in isotacticity distributions. With increasing molecular weight of components containing crystallizable units, the isothermal crystallization rate exhibited a higher temperature dependence. When the isotactic defects in polypropylene chains increase with the molecular weight of components, both the fold surface free energy σ_e and the work of chain folding q decreases, in spite of the higher molecular weight. © 2002 Society of Chemical Industry