GMS卫星红外云图数据压缩

依据ＧＭＳ卫星红外气象云图的统计特性,提出了一种“亚抽样＋修改的ＪＰＥＧ＋图象放大”的静止图象编码方法,使有失真压缩比在５０∶１至１００∶１时,恢复图象峰值信噪比在３５ｄＢ～４０ｄＢ之间,主观质量无视觉可觉察到的失真。对于信息保持型ＧＭＳ卫星红外云图数据压缩,选取训练集求取最小均方误差意义下的最佳线性预测器,并作为固定预测器应用于每幅云图,性能优于目前文献报导的固定预测器。     

聚氨酯-丙烯酸酯核壳乳液的制备及其性能的研究

本文研究了以种子乳液聚合法制得的聚氨酯—丙烯酸酯胶乳粒子。以PA为核，PU为壳的核壳乳液的成膜性能较丙烯酸树脂的成膜性能有明显的改善。     

两种新型增强剂的协同作用

本文研究了两种新型造纸助剂--阴离子改性明胶和阳离子PAM乳液作为纸张增强剂的协同应用效果.结果表明,在合适的条件下它们对麦草浆既有较好的增强效果,同时还能改善浆料的留着和滤水性能.     

Chitosan inhibits premature browning in ground beef

Our objective was to evaluate the effect of chitosan on premature browning in refrigerated ground beef patties stored in different packaging systems. Ground beef patties (15% fat) with chitosan (1% w/w) or without chitosan (control) were individually packaged either in vacuum (VP), aerobic packaging (AP), carbon monoxide modified atmosphere packaging (LO-OX; 0.4% CO+19.6% CO(2)+80% N(2)), or high-oxygen modified atmosphere packaging (HI-OX; 80% O(2)+20% CO(2)), and stored for 0, 1, or 3 days at 1°C. At the conclusion of storage, raw surface redness was evaluated, patties were cooked to internal end-point temperatures of either 66°C or 71°C, and internal cooked color was measured. The incorporation of chitosan increased (P<0.05) the interior redness of patties stored in AP, VP, and LO-OX, but not in HI-OX. The results of the present study suggest that the incorporation of 1% chitosan minimizes premature browning in ground beef patties stored under AP, VP, and LO-OX.     

Thermal properties of new varieties of yam starches

Starches isolated from yam varieties of Dioscorea alata and Dioscorea cayenensis‐rotundata species were prepared at different time–temperature conditions and characterised by DSC, amperometric iodine titration, light microscopy and rheology and compared to native and chemical modified tapioca starches. The observation by light microscopy showed different morphologies of the granules when heated above 100°C and the tendency for disintegration decreased in the order native tapioca starch > yam starch > modified tapioca starch. Differences between yam and tapioca starches were also revealed by DSC. Yam starch enthalpy is higher than tapioca starch, but the peak temperature is low. However, the significant differences between yam and the other tested starches were found in terms of their rheological behaviour. The viscosity of yam starch was very stable at high temperatures on the viscograph. With this property, yam starch can be used as thickening and gelling agent in food.     

Use of carbon dioxide enriched atmospheres in the refrigerated storage (2 °C) of salmon (Salmo salar ) steaks

 Selected microbial counts (total viable microbiota, Brochothrix thermosphacta, lactic acid bacteria and Enterobacteriaceae), biochemical parameters [pH, total volatile nitrogen, nucleotide breakdown products, non-volatile amines, d(–) and l(+)-lactic acids and short-chain fatty acids] and sensory attributes (colour and odour) of refrigerated (2  °C) salmon (Salmo salar) steaks stored under CO₂-enriched [CO₂/air (20/80, v/v), CO₂/air (40/60, v/v)] and air atmospheres were determined. When compared with air, sensory results showed shelf-life extension of 6 days and 15 days for 20% and 40% CO₂-enriched atmospheres, respectively. Microbial and biochemical results also revealed that the 40% CO₂-enriched atmosphere was the most effective packaging type for refrigerated salmon. Received: 22 April 1999     

PAE与聚丙烯酸丁酯／甲基丙烯酸甲酯核壳乳液的共混改性及其应用研究

运用粒子设计的方法制备了ＰＡＥ改性的聚丙烯酸丁酯／甲基丙烯酸甲酯核壳乳液。该乳液颗粒具有软核硬壳结构,表面吸附了一层ＰＡＥ大分子,呈阳电性。在纸浆中添加少量该乳液即能明显改善纸张的干、湿强度和柔软度。     

基于多源信息的发动机无故障数据可靠性评估

针对弹用发动机无故障数据可靠性评估问题,提出基于多源信息的可靠性评估方法;综合应用修正极大似然估计和Bayes估计方法,给出信息源权值的计算公式和可靠性评估步骤,最后给出应用实例.计算结果表明,多源信息融合方法计算简单,评估结果合理,具有一定工程应用价值.     

Solubility and absorption rate of carbon dioxide into non-respiring foods. Part 3: Cooked meat products

The solubility and diffusion of carbon dioxide into cooked meat products (cooked ham and meat sausage with different pH-levels) was determined at different starting pressures and gas to product volume ratios by monitoring pressure changes over time in a closed chamber at constant temperatures (0, 4, and 8 °C). Good correlation of the CO₂ solubility between the packaging parameters (gas to product volume ratio and initial partial pressure) and the meat products water content was found. The solubility of CO₂ followed Henry’s law and the initial partial pressure of CO₂ influenced the solubility mostly. Only small variations in the diffusion constants and absorption rates were found within the experimental design. A pH difference of 0.5 in the two meat sausage types did not influence either solubility or diffusion significantly.