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991.
J. W. Park P. M. Scott B. P. -Y. Lau D. A. Lewis 《Food Additives & Contaminants》2004,21(12):1168-1178
Thirty retail samples of heat-processed corn foods, i.e. corn flakes, corn-based breakfast cereals, tortilla chips and corn chips, were analysed for fumonisins — fumonisin B1 (FB1), fumonisin B2 (FB2) and hydrolysed FB1 (HFB1) — as well as for protein- and total-bound FB1. Bound (hidden) fumonisins cannot be detected by conventional analysis. Improved methods for the determination of bound FB1 were developed. The protein-bound FB1 was extracted with 1% sodium dodecylsulfate (SDS) solution. The SDS, which interfered with high-performance liquid chromatography (HPLC) analysis, was then separated from protein-bound FB1 by complexing with methylene blue followed by solvent extraction and hydrolysis with 2 N KOH. To measure total-bound FB1, the sample itself was hydrolysed with KOH. In both cases, clean-up was accomplished on an OASIS polymeric solid-phase extraction column and the bound fumonisins were determined by HPLC measurement of HFB1. Fourteen of 15 samples of corn flakes and other corn-based breakfast cereals analysed contained detectable levels of FB1 with a mean in positive samples of 67 ng g-1 (13-237 ng g-1). Two samples also had detectable levels of FB2 (21-23 ng g-1). Bound FB1 was found in all samples; the mean protein-bound FB1 measured was 58 ng g-1 (22-176 ng g-1) and the mean total-bound FB1 measured was 106 ng g-1 (28-418 ng g-1), reported as FB1 equivalents after correction for recoveries of HFB1. There was an average of about 1.3 times more FB1 in the bound form compared with extractable FB1, and this was about twice as much as protein-bound FB1. Seven of the 15 samples of alkali-processed corn-based foods, such as tortilla chips and corn chips, contained FB1 and three contained HFB1 with means in measurable positive samples of 78 (48-134) and 29 (13-47) ng g-1, respectively. Five of these alkali-processed corn foods contained bound FB1; the mean measurable protein-bound FB1 was 42 ng g-1 (39-46 ng g-1) and the mean measurable total-bound FB1 was 100 ng g-1(54-209 ng g-1). HFB1 derived from bound FB1 in selected samples was confirmed by HPLC with mass spectrometry (MS). 相似文献
992.
利用Mises屈服条件建立了确定钢制压力容器焊接残余应力的方法,即只要测点进入屈服状态,就完全可以确定该点两个主应力方向的残余应力。并指出该方法是一种确定钢制压力容器残余应力的简易方法。 相似文献
993.
4A沸石生产过程中,水热合成反应(溶铝、混胶、结晶)在夹套反应釜中进行。结晶的4A沸石沉积于釜底。因此结晶时间成为影响产量的限制因子。该文针对性地提出增加结晶池,在反应釜中完成水热合成反应之后,转入结晶池完成结晶工艺,提高反应釜的利用率,从而提高产量。 相似文献
994.
Simulation techniques used in the Manufacturing Test SIMulator(MTSIM) are described. MTSIM is a Concurrent Engineering tool used tosimulate the manufacturing test andrepair aspects of boards and MCMs from design concept through manufacturing release. MTSIM helps designers select assemblyprocess, specify Design For Test (DFT) features, select board testcoverage, specify ASIC defect level goals, establish productfeasibility, and predict manufacturing quality and cost goals. A newyield model for boards and MCMs which accounts for theclustering of solder defects is introduced and used topredict the yield at each test step. In addition, MTSIMestimates the average number of defects per board detected at eachtest step, and estimates costs incurred in test execution, faultisolation and repair. MTSIM models were validated withhigh performance assemblies at Hewlett-Packard (HP). 相似文献
995.
RHZ-300YL型裂化催化剂的研制及其在印度尼西亚的应用 总被引:1,自引:0,他引:1
针对印度尼西亚SUNGAI GERONG炼油厂重油催化裂化装置的特点及对产品的要求,开发了RHZ-300YL型催化剂。该剂采用了超稳Y型分子筛的改性技术及活性担体技术,并对催化剂配方进行了优化,使该剂具有重油裂化能力强、活性稳定性好、丙烯及汽油产率高等特点。该剂在印度尼西亚SUNGAI GERONG炼油厂催化裂化装置工业应用表明。在掺炼渣油的条件下,丙烯产率达到5.65%,汽油产率达到50.5%。 相似文献
996.
简述了钢锭断面形状对厚板成材率的作用。着重阐述模拟舞阳钢铁公司4200mm厚板轧机的轧制工艺条件,轧制8.0t镇静钢扁锭,采用正交设计法确定钢锭断面最佳尺寸。得到了在确定轧制工艺条件下,正确确定最佳钢锭断面尺寸的正交回归数学模型。在本实验最佳断面形状的锭型与合适的工艺相匹配下,厚板成材率约提高5.276%,边部切损率约降低3.635%。 相似文献
997.
介绍了大庆蜡油掺炼渣油催化裂化增产柴油工业试验。标定数据表明,使用DMC-2催化剂,选择适当的操作条件,凝点为-10℃柴油产率可达33%,柴汽比为0.87。同时轻质油收率保持在70%以上,汽油辛烷值没有明显的变化。 相似文献
998.
999.
Sveinung Birkeland & Bjørn Bjerkeng 《International Journal of Food Science & Technology》2005,40(9):963-976
The effects of temperature (4 and 10–12 °C) and time (6, 12 and 24 h) on colorimetric parameters (Commission International de l'Eclairage (CIE) L*a*b*), carotenoid concentration, salt content and yield were investigated in brine (saturated or 50% saturation) and dry salted fillets of cold‐smoked Atlantic salmon (Salmo salar). Lightness (L*), yellowness (b*), hue (Hab) and chroma (C*) values were lower at 10 than 4 °C (P < 0.01), whereas redness (a*) was unaffected. L* increased (P < 0.05) and a*, b*, Hab and C* values dropped when salting time was increased (P < 0.001). Astaxanthin concentration of brine‐salted fillets decreased with increasing salting time (P < 0.05), but was unaffected by salting temperature. Increasing salting time affected colour negatively. The salt content of dry salted fillets increased with temperature and salting time. The process yield was unaffected by temperature and decreased with salting time. In conclusion, the cold smoking process is more important for variation in quality parameters than the salting process. 相似文献
1000.
J.L. Su School of Mechanics-Electrics Engineering Fujian Agriculture Forestry University Fuzhou China G.K. Hu Department of Applied Mechanics Beijing Institute of Technology Beijing China Manuscript received December in revised form June 《金属学报(英文版)》2005,(6)
1. Introduction Intermetallic titanium aluminides are potential new structural materials in high temperature applica- tions[1-3]. These γ-TiAl based alloy materials usually have a two-phase microstructure, composed of a γ- TiAl (L10-structure, tetragona… 相似文献