物像互遮掩的彩虹全息记录

提出了一种使多个物体的再现像间有相互遮掩效果的彩虹全息记录方法。在主全息图记录光路中设置系列互补的挡光屏，对不同的物体分别进行记录；所得到的彩虹全息图再现时，左右移动观察，将看到不同物体的再现像在视场中逐渐交替出现，沿挡光屏边缘相互遮掩。给出了挡光屏的设置参数，并完成了“天狗袭日”彩虹全息图的设计和制作，获得了满意的效果。     

Iron-Fortified Infant Cereals

Infants are particularly susceptible to iron deficiency and related anemia due to their high growth rates and the low iron content of breast milk and most unfortified weaning foods. Cows' milk also is poor in iron, and certain forms of cows' milk cause blood and thus iron loss from the gastrointestinal tract. Iron-fortified cereal-based complementary foods – infant cereals – are recommended to supply the iron needs of older infants. Fortified infant cereals contain much more iron than other fortified cereal products – up to ten or fifteen times as much. Highly or slightly soluble iron salts have excellent bioavailability, but affect color and reduce chemical stability, so these iron salts are not commonly used to fortify infant cereals. Insoluble sources of iron, such as the iron phosphates, were used historically to fortify infant cereals, but these sources have very poor bioavailability. Infants depending on these cereals for iron suffered from high rates of iron deficiency and anemia.

Elemental iron of small particle size, particularly electrolytic iron, currently is the generally accepted vehicle for infant cereal fortification. Iron-fortified cereal made with electrolytic iron reduces iron deficiency and related anemia in several settings but unfortunately is not fully protective in all. Ascorbic acid is a known enhancer of iron bioavailability but ascorbic acid is heat-labile and ascorbic activity declines rapidly during storage. Nonetheless, adding ascorbic acid during processing appears to improve the availability of electrolytic iron and thus the reliability of iron-fortified infant cereal as a means of preventing iron deficiency in older infants.     

3种前处理-HPLC法测定婴幼儿配方食品中维生素B1

分别采用国标法(GB 5009.84-2016)、酸解法和等电点法处理试样,用高效液相色谱-荧光检测(HPLCFLD)法测定婴幼儿配方乳粉和婴幼儿谷类辅助食品中的维生素B1。结果表明,维生素B1在3.036~303.6 ng/mL范围内线性良好,相关系数R^2>0.999。3种方法的回收率和相对标准偏差(RSD,n=6)均符合要求。其中,国标法和酸解法的RSD值相对较小,等电点法的RSD值偏大。试样经国标法、酸解法处理测得维生素B1含量与标签一致,少数试样经等电点法处理测得维生素B1含量明显偏低。酸解法相较于国标法,省去了耗时最长的酶解步骤,仍获得良好回收率。可见,酸解法前处理简单,耗时短,结果准确度高,重现性好,适用于批量检测,总体优于国标法和等电点法。     

Nutritional quality of complementary food prepared from unmalted and malted maize fortified with cowpea using extrusion cooking

The nutritional quality of extruded unmalted or malted maize fortified with cowpea as complementary food was assessed based on its proximate analysis, amino acid composition and results from rat feeding with the blends. Results indicated a slight decrease and increase in protein content due to malting and extrusion respectively. The changes in fat, crude fibre and ash content were not significant. The blends were a good source of energy, ranging from 1831 to 2045 kJ per 100 g. Extrusion significantly increased the amino acid content of the blends, while malting had a varied effect on each of the amino acids. There was no significant difference in the protein efficiency ratio (PER), net protein ratio (NPR) and weight gain of rats fed the blends when compared with the control (casein diet). The present study shows that malting improved the nutritional quality of the blends. Rats fed the casein diet had higher values for total digestibility (TD) and net protein utilisation (NPU). There was no significant difference (P > 0.05) in the internal organ weights of rats fed all blends except the protein‐free diet. © 2000 Society of Chemical Industry     

带有旁通补燃的相继增压柴油机的计算分析

提出一种带有旁通补燃的相继增压系统,并通过计算分析揭示了它的优越性,它不但具有旁通补燃系统的全部优点,并大大地改善了其低负荷时的经济性。     

STRESS- AND ROTATION-BASED HIERARCHIC MODELS FOR LAMINATED COMPOSITES

A hierarchic sequence of equilibrium models in terms of stresses assumed to be not a priori symmetric is derived for cylindrical bending of laminated composites, using first-order stress functions. The stress field of each hierarchic model satisfies a priori (i) the translational equilibrium equations and the stress boundary conditions of two-dimensional elasticity, and (ii) the continuity requirement for the transverse shear and normal stresses at the lamina interfaces. The levels of hierarchy correspond to the degree to which the two first-order compatibility equations and the rotational equilibrium equation of two-dimensional elasticity are satisfied. The numerical solution is based on Fraeijs de Veubeke's dual mixed variational principle, employing the p-version of the finite element method. The number of degrees of freedom is independent of the number of the layers in the laminate. Results are obtained directly for the stresses and rotations; the displacement field is obtained in the post-processing phase by integration. Numerical results with comparisons show the capability of the mathematical and numerical models proposed.     

Additive-additive and additive-surface interactions in lubrication

Combinations of additives are often found to exhibit antagonistic or synergistic effects compared to the performance of the individual additives. This paper reviews the state of knowledge concerning such effects. Direct interactions, where two additives combine at a molecular level, are distinguished from complementary or exclusary effects where the individual contributions of separate additives enhance or reduce overall performance but with no direct interaction. Additive interactions take place in solution and at surfaces, and both are discussed.     

Effect of ultrasound on bubble breakup within the mixing chamber of an effervescent atomizer

Gas bubbles introduced into a liquid in the mixing chamber help to break up the liquid into fine droplets on being expanded to the ambient pressure. The passage of gas bubbles through the orifice of the nozzle requires that the size of the bubbles be much smaller than the diameter of the orifice. In the present work, the effectiveness of 20 kHz ultrasound to increase number density of fine bubbles within the mixing chamber of an effervescent atomizer by breaking up bubbles introduced in it by an aerator was investigated. Bubbles of initial size in the range of 5-10 mm were shown to get disintegrated into clusters of micron and sub-micron sized bubbles. A fine spray was produced in the presence of ultrasound at a gas-to-liquid mass flowrate ratio (GLR) of 0.063%. The half-cone angle of spray was in the range of 6-10°, which compares favorably with conventional atomizers. The experimental findings of bubble breakup were theoretically modeled by the Rayleigh-Plesset equation. The results of the model indicate that bubbles having initial radius less than 3 mm undergo growth and subsequent disintegration at 20 kHz for the given acoustic pressure of 0.3 MPa.