MASS TRANSFER-REACTION COUPLING PRODUCES MULTIPLE SUBSTRATE CONCENTRATIONS AT FLOC SURFACE: SUBSTRATE INHIBITED KINETICS

Simplistically, the whole cell can be modelled as a well mixed substrate sink, enveloped by a diffusive barrier (the cell membrane). In this communication we use this model in describing diffusion and reaction within a cell floe, subject to substrate inhibition. The cell floe is pictured as an array of well mixed environments between which substrate transfer occurs. When the observed rate of substrate uptake by the floe is equated to the substrate transport rate across the extra-floe stagnant liquid film, multiple interface concentrations are possible. Their number increases as intra-floe diffusion influences the observed reaction rate. More fundamentally, this is the first time that more than three steady states have been predicted using the particular graphical technique with substrate inhibited kinetics.     

综合物探在山区构造复合部位找水中的应用

以综合物探寻找山区构造复合部位找水为例, 介绍了在水工环物探找水工作中, 根据不同的地貌地质单元、 地 质地球物理特征以及地形条件, 合理布置物探剖面, 因地制宜进行探测, 并对不同的电性参数进行认真分析研究, 取 得了较好效果。对找水工作具有一定的借鉴意义。     

Spectral variations of coastal water irradiance as a measure of phytoplankton pigments

Spectral irradiance data were collected along the coast of British Columbia, Canada, using a submersible spectroradiometer. The corresponding hydrographic observations show that in general, the surface layer where the irradiance measurements were taken, is a well mixed layer. The spectral variations of the data are interpreted with respect to the changes of chlorophyll α and phaeo-pigment concentrations measured at the same time. Optical properties such as spectral attenuation and back scattering coefficients are estimated from the data. The back scattering coefficient is approximated by an expression obtained from theoretical analysis.

For remote sensing applications, the intercomparisons of algorithms of Gordon et al. (1980) and Kim et al. (1980) are presented. The results indicate that a linear form of the relationship is suitable for estimating the amount of chlorophyll α + phaeopigments in the coastal water of the inshore region. This may be explained by the variations of diffuse reflectance ratio between wavelengths 420 and 560 nm corresponding to the absorption maximum and minimum due to the presence of phytoplankton pigments in the sea water.     

两种加压浸出工艺处理锌浸出渣试验

开展了两种加压浸出工艺处理锌浸出渣的试验研究。“加压还原浸出+氧压浸出”取代原针铁矿工艺的“三段逆流热酸浸出+还原”,锌焙烧矿到铅渣的渣率为15.74%,锌、铁、铜、铟、镁的浸出率分别为99.32%、93.50%、95.02%、91.03%、99.97%,各项指标均优于原工艺,锌、铟的浸出率分别提高了1.82、11.03个百分点,反应时间由14 h缩短为4 h,液固分离次数由4次减少为2次。“两段逆流加压浸出”取代原黄钾铁矾工艺的“硅浸+预中和+黄钾铁矾沉铁”,锌焙烧矿到二段渣的渣率为35.88%,锌、铁、铜、铟、镁的浸出率分别为98.50%、4.94%、90.48%、2.69%、93.77%,各项指标均优于原工艺,浸出后液（相当于水解除铁后液）可以直接返回中性浸出工序,反应时间由16 h缩短为4 h,液固分离次数由3次减少为2次。加压浸出采用密闭的加压釜,更容易实现整个炼锌系统蒸汽平衡,无需额外增加蒸汽锅炉。     

线阵CCD信号的小波去噪方法研究

随机噪声是影响CCD器件输出信号信噪比的主要因素,它包括1/f分形噪声和白噪声.使用传统方法去除分形噪声效果比较差,而小波变换是一种具有一定时间和频率分辨率的方法,它能够较好的滤除分形噪声.就如何在小波变换域进行参数估计,给出了确定阈值的方法,并在此基础上对TCD142D线阵CCD输出信号进行滤波,结果表明了该方法的有效性.     

EFFECT OF DIETARY VITAMIN E AND SURFACE APPLICATION OF OLEORESIN ROSEMARY ON IRON/ASCORBATE-STIMULATED LIPID OXIDATION IN MUSCLE TISSUE AND MICROSOMES FROM RAINBOW TROUT (Oncorhynchus mykiss)

The effect of dietary α-tocopheryl acetate and surface application of oleoresin rosemary on iron/ascorbate-induced lipid oxidation in rainbow trout ( Oncorhynchus mykiss ) muscle and microsomes was investigated. The 2-thiobarbituric acid-reactive substances (TBARS) values of muscle and microsomes isolated from fish fed the higher concentration of α-tocopherol (500 mg/kg feed) were smaller than those of fish fed the lower concentration (100 mg/kg feed). The protective effect of oleoresin rosemary on lipid oxidation in fish muscle was also observed. Analysis of variance revealed a significant (p < 0.01) interaction between dietary treatments and incubation time. Dietary α-tocopherol supplementation significantly increased the α-tocopherol concentration of muscle microsomal membranes, thereby increasing the oxidative stability of the membrane lipids.     

Oxygen Diffusion Coefficients in Alkali Silicates

Oxygen self-diffusion coefficients in molten alkali silicates were measured by the technique of heterogeneous isotopic exchange with a gaseous phase enriched in ¹⁸O. For the composition 64 wt% SiO₂-36 wt% K₂O, the diffusion coefficients from 700° to 1000°C under 100 torr O₂ pressure are described by The effect of pressure on D _O*, studied for the same composition at 900°C under O₂ pressures of 20 to 400 torr, is described by D _O*= kP _O2^{−(0.44±0.09)}. For the composition 75 wt%SiO₂-25 wt% K₂O, the diffusion coefficients from 750° to 1000°C under 100 torr O₂ pressure are described by The effect of pressure on the self-diffusion coefficients can be explained by a diffusion mechanism involving O vacancies.     

YIELD BEHAVIOUR OF CRUMBLY ENGLISH CHEESES IN COMPRESSION

Compression measurements on samples of Cheddar, Cheshire and Leicester cheeses with an Instron Universal Testing Machine indicate the presence of a yield point characteristic of crumbly foods. The force and nominal strain at the yield point were studied as a function of deformation rate, temperature and pre-yield compression history. A recently proposed non-linear viscoelastic model with a single fracture element fits individual compression curves, but the model has little predictive capability.     

Effects of Frying Procedures and Compositional Factors on the Temperature Profile of Bacon

The effects of frying procedures (preheated vs cold skillet) and compositional factors (adipose vs lean) on the final temperatures attained in fried bacon were investigated as a prelude to studying the kinetics of N-nitrosopyrrolidine formation in bacon. With a preheated skillet set at 171°C, the final temperature reached in whole bacon samples at the end of the 6 min frying time was 164 ± 3°C. Bacon samples, initially placed in a cold skillet preset to heat to 171°C, attained temperatures of 127 ± 5°C and 165 ± 6°C at the end of 6 and 8 min frying periods, respectively. It was observed that the lean bacon strips rarely exceeded 145°C while the adipose approached 165°C when separated adipose and lean components from whole bacon samples were fried for 6 min in a preheated (171°C) skillet.