稻田渍水及土壤水分平衡对春玉米生长影响的模拟分析

借助Penning de Vries的MACROS模型和1995～1997年田间及水槽实验结果，建立了玉米生长发育及水分动态耦合的模拟模型，模型模拟的玉米地上部干物质积累、土壤水分变化状况同实际较为符合。验证后的模型用于模拟不同渍水时期及持续时间对春玉米生长及产量影响的动态。模拟结果表明在田间全程控制水分为田间持水量90%情况下，春玉米孕穗期为渍水危害的敏感期，其次为4～6叶期。在自然降水及土壤渍水状况影响下，春玉米幼苗期4～6叶时为渍水的敏感期，8叶及孕穗期相对较耐渍。在玉米4、6叶期时，渍害造成产量下降的临界期为5d；而在8叶、孕穗期为10～15d.但持续20d的渍水对任何时期的春玉米生长都造成严重的影响。因此在生产中应注意在苗期及孕穗期及时排除田间多余的水分及降低地下水位。     

紫玉米色素的稳定性研究

本文对紫玉米花色苷稳定性进行了系统的研究,紫玉米色素对光、pH、温度、金属离子、食品添加剂、辐照、高温高压等具有一定的稳定性.结果表明,在酸性条件下,该色素稳定性较好,在食品工业中具有一定的利用价值.     

几种玉米种子处理剂防治草地贪夜蛾药效试验

为压低前期虫口基数,筛选对草地贪夜蛾防效较好的种子处理剂,设计并开展此试验.试验结果表明,几种种衣剂对玉米生长安全,在玉米生长前期4个处理对草地贪夜蛾的防效均超过60％.防效最好的为40％溴酰·噻虫嗪FS 450 g/100 kg种子处理,平均保苗率为89.97％,播种后21 d虫口防效为91.21％;其次为50％氯虫...     

夏热冬暖地区办公建筑节能设计探讨

夏热冬暖地区具有自身的特点,以深圳特区为例,分析夏热冬暖地区办公建筑的耗能现状,提出符合夏热冬暖地区气候、经济、环境条件的办公建筑设计的节能措施。     

Moisture Dependent Physical Properties of Dry Sweet Corn Kernels

Physical properties of sweet corn kernels have been evaluated as a function of kernel moisture content, varying from 9.12 to 17.06% (db). In the moisture range, kernel length, width, thickness, and geometric mean diameter increased linearly from 9.87 to11.09 mm, 7.41 to 9.25 mm, 3.25 to 4.37 mm, and 6.18 to 7.62 mm, respectively, with increase in moisture content from 9.12–17.06%. The sphericity index, kernel volume, kernel surface area, and thousand seed weight increased linearly from 62.6 to 68.8, 93.8 to 194.3 mm³, 120.1 to 182.9 mm², and 220 to 268 gr, respectively. Apparent density and bulk density decreased linearly from 1.315 to 1.232 g/cm³ and 0.765 to 0.698 g/cm³, respectively, while bulk porosity increased from 41.8 to 43.3%. The highest static coefficient of friction was found on the plywood surface. The static coefficient of friction increased from 0.680 to 0.891, 0.605 to 0.741, and 0.530 to 0.644 for plywood, galvanized iron, and aluminum surfaces, respectively. The angle of repose increased linearly from 30.2 to 35.2° with the increase of moisture content.     

Pheromone Response Inhibitors of the Corn Stalk Borer Sesamia nonagrioides. Biological Evaluation and Toxicology

The behavioral activity of some trifluoromethyl ketones (TFMKs) as inhibitors of the pheromone activity of the corn stalk borer Sesamia nonagrioides (Lef.) (Lepidoptera: Noctuidae) is reported. The most closely-related analogue to the pheromone tested, (Z)-11-hexadecenyl trifluoromethyl ketone (Z11-16:TFMK), elicited a significant decrease in the number of male catches in traps baited with mixtures with the pheromone in 1:1 and 10:1 ratios in comparison to the pheromone alone. The E isomer of the analogue as well as two highly hydrated ketones, 3-octylthio-1,1,1-trifluoropropan-2-one (OTFP) and 1,1-difluoropentadecyl trifluoromethyl ketone, were inactive. Conversely, the saturated TFMKs n-dodecyl trifluoromethyl ketone and, particularly, n-hexadecyl trifluoromethyl ketone induced a synergistic effect when mixed with the synthetic pheromone in 10:1 ratio. However, in a wind tunnel these chemicals did not elicit any differential effect on flying moths attracted to a source containing a 10:1 blend of the analogue and the pheromone. In a dual choice bioassay with two dispensers, containing the pheromone alone, and mixtures of Z11-16:TFMK and the pheromone and separated 5 cm apart, males showed no particular preference for either dispenser. The ketone mixture, however, induced moths to execute erratic flights with frequent crosswind counter-turns and intersections with plume boundaries. The total number of contacts with the source were reduced when a control dispenser was paired with a dispenser containing Z11-16:TFMK and pheromone. Z11-16:TFMK and OTFP showed little toxicity on mice with a LD₅₀ of 1 g/kg after the 6th day of treatment. For comparitive purposes, the major component of the pheromone, Z11-16:Ac, displayed a LD₅₀ of 5 g/kg 6 days after application. Our results provide additional information about the activity of the TFMKs, which might be useful for the utilization of these chemicals in future pest control studies.     

Modeling calcium and water intake in threshed corn grain during thermo-alkaline treatment

A mathematical model describing simultaneous solvent diffusion and gelatinization of starch was used to explain the water and calcium absorption in threshed corn grains during the thermo-alkaline treatment. A computer-aided nonlinear optimization technique was used to find the effective diffusion coefficients and the reaction rate constants of water and calcium in threshed corn grains at boiling temperature (92.5 ± 0.3 °C). The mathematical model shows good correlation between measured and predicted values of water and calcium intake. It is concluded that the cooking process is limited by the reaction of starch components with water and calcium. The effective diffusion coefficient for water varied between 1.18 × 10⁻¹⁰ and 1.45 × 10⁻¹⁰ m²/s and for calcium between 8.55 × 10⁻¹⁰and 16.77 × 10⁻¹⁰ m²/s. The diffusion of water and calcium in threshed corn was produced with a reaction rate constants in the range of 6.83 × 10⁻⁴ to 10.4 × 10⁻⁴ s⁻¹ for water and 2.7 × 10⁻⁵–7.6 × 10⁻⁵ s⁻¹ for calcium. According to these effective diffusion coefficient values the diffusive process seems to be slower for water than for calcium. However, the reaction rate constant values are approximately 10 times higher for water than for calcium which may indicate that a higher amount of solvent was linked in the water diffusion process due to the gelatinization. Low concentration of Ca(OH)₂ such as 0.10% did not significantly affect the water diffusion of threshed corn during the cooking process.     

玉米淀粉在糖化中的应用

本文介绍了玉米淀粉的特性，比较了使用玉米淀粉作辅料的优势及糖化生产中应满足的设备、工艺要求，分析了玉米淀粉代替大米作辅料对啤酒质量的影响。     

亚硫酸化玉米油的研制与应用

本文书回归分析和最优化技术应用于玉米油的亚硫酸化研究。用模糊控制评分法将加脂乳液稳定性数量化，采用改进的逐步回归分析法，调用ＡＳＲＡ软件，建立了亚硫酸化产物乳液稳定性与温度，空气流量，ＮａＨＳＯ３用量和反应时间之间关系的数学模型，并用非线性规划方法寻求最佳工艺条件。优化所得工艺条件的特点是ＮａＨＳＯ３用量少，反应时间短。所得亚硫酸化玉米油乳液稳定性好。应用实验表明，该加脂剂在革内渗透深，分布均匀，加脂后的革含油量高，柔软，丰满，具有高的抗张强度。其加脂性能达到或超过国内同类产品的水平。在对亚硫酸化玉米油的研制和应用中，使用了化学方法，ＩＲ技术，并对加脂革进行了光学显微镜的观察。