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A method for the rapid and quantitative determination of aflatoxin B1 from small quantities of liver, around 1-2 g, is described. The extraction procedure involves acidification to pH 2 of the aqueous liver homogenates, extraction with chloroform: acetone and HPLC-fluorimetric detection after derivatization with trifluoroacetic acid. Quantitative recovery of aflatoxin B1 from chick liver was achieved and detection at levels of 0.2-1 ppb was proved feasible. The aflatoxin B1 concentration in chick liver after oral administration is also shown. 相似文献
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Baudilio Coto Carmen Martos Jos L. Pea Juan J. Espada María D. Robustillo 《Fuel》2008,87(10-11):2090-2094
Wax precipitation is one of the most important flow assurance problems. Unfortunately, experimental data are very scarce to confirm existing models for prediction of such precipitation problem. This work reports a new experimental method. Multistage fractional wax precipitation was carried out by decreasing the temperature of crude oil. No solvent dilution was used, so the effect of solvent on temperature wax precipitation was avoided. The reproducibility of the method was tested with comparable results. The precipitation curve and the wax appearance temperature were obtained for two crude oils with different chemical nature using the reported method. 相似文献
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MJ Reardon TD Hedrick GV Letsou HJ Safi R Espada JC Baldwin 《Canadian Metallurgical Quarterly》1997,64(5):1480-1482
Chronic traumatic aneurysm of the thoracic aorta is an unusual occurrence. Previously, arteriography was performed on all patients seen in our institution with this entity to allow confirmation of the diagnosis and anatomic delineation for operation. A case of chronic traumatic aneurysm of the distal descending aorta discovered on a routine chest roentgenogram and evaluated with chest computed tomographic scanning with three-dimensional reconstruction is presented. It is our belief that not all thoracic aneurysms require arteriography, and improved methods of computed tomographic scanning allow adequate diagnosis and anatomic delineation with decreased morbidity and cost. 相似文献
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Jordán Pascual Espada Vicente García-Díaz Edward Rolando Núñez-Valdéz Rubén González Crespo 《国际智能系统杂志》2019,34(9):2243-2252
Intelligent security systems have evolved enormously in the last few years. Most of these security systems use a group of physics sensors and algorithms for data analysis and communication systems to notify security alarms. Many security systems that are included in doors can detect intruders when they have already opened the door, but not while intruders are forcing upon the door. However, some security systems include preventive systems, which can detect intruders before they open the door. These preventive systems are usually based on video cameras (image processing) or in-presence sensors, which can generate many false positives, for instance, when a person is next to the door for a few seconds, even if this person is not manipulating the door. This research work proposes a novel force door detection system. The system includes a specific device for monitoring door small vibrations and movements; it analyzes these data using neural networks to detect accurately if someone is forcing upon the door. Artificial intelligence must be able to categorize data records without confusing when someone is forcing upon the door with other actions, like knocking on the door. 相似文献
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