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61.
Elham Sobhanzadeh Nor Kartini Abu Bakar Mhd Radzi Bin Abas Keivan Nemati 《European Journal of Lipid Science and Technology》2011,113(7):862-869
This work reports a simple, rapid, and effective extraction method based on liquid–liquid extraction (LLE) followed by matrix solid‐phase dispersion‐sonication for detection, identification and quantification of multiclass pesticides in virgin olive oil using liquid chromatography mass spectrometry (LC‐QTOF‐MS). LLE to extract pesticide residues in virgin olive oil was performed in order to study the centrifugation efficiency to obtain high recovery yield and low co‐extract fat residue in the final extract. Different suitable parameters of MSPD procedure were evaluated, such as nature of dispersing phase, clean‐up adsorbent, and volume of eluting solvent (acetonitrile) in different extraction conditions, with or without sonication. The best results were obtained using 5 g of virgin olive oil, 2 g of PSA as dispersant sorbent, 2 g of Florisil/GCB (70:30 w/w) as clean‐up sorbent, and 15 mL of acetonitrile as eluting solvent under conditions of 15 min ultrasonic bath at RT. Method validation was performed in order to study sensitivity, linearity, precision, and accuracy. Average recoveries ranged between 73.7 and 104.2% with relative SDs 5.3–13.4% at three concentration levels (25, 50, and 100 µg/kg). Detection and quantification limits ranged from 1.5 to 5 µg/kg and 3 to 9 µg/kg, respectively. 相似文献
62.
D. Rèche T. SturelO. Bouaziz A. ColA.F. Gourgues-Lorenzon 《Materials Science and Engineering: A》2011,528(15):5241-5250
In order to optimize the metallurgical quality of advanced high strength steels for automotive applications, the present study aims at understanding damage mechanisms involved in air-bending of two low alloy TRansformation Induced Plasticity (TRIP)-aided steels. Air-bending tests were performed together with metallographic investigations of damage development in bent specimens. In order to assess the role of hard bands induced by chemical segregations, air-bending tests on specimens with various locations of the main hard band (with respect to the neutral fibre) were performed. Cracking initiates from the outer surface or from just below, mainly by decohesion between ferrite and secondary (martensite) phases, at hard bands located close to the outer surface. From these examinations, together with a simple kinematics analysis of bending, a quantitative relationship between cracking, local thickness of hard band and local “mesoscopic” strain is proposed. 相似文献
63.
林华 《中国锅炉压力容器安全》2009,(9):47-50
简述超临界锅炉特点、安装工艺特点及安装质量监督检验工作性质、意义,详细介绍超临界锅炉安装监督检验工作内容、方法及安装监督检验工作中发现的主要问题,并提出超临界锅炉安装监督检验工作的合理化建议,提高超临界锅炉安装质量。 相似文献
64.
Twin roll strip casting can be an effective alternative to produce high manganese TWIP steel, which provides extraordinary mechanical properties. In the work presented, 1.5–3 mm thin hot strips with up to 30 wt% manganese were produced directly from the melt and further processed to cold strip. An adapted thermo-mechanical treatment, consisting of cold rolling with or without subsequent annealing, enables to adjust different material states, such as recrystallised or strengthened state, and thus to tailor the mechanical properties. As an example for the superior crash behaviour of high manganese TWIP steels, dynamic crash tests were carried out using cold rolled Fe–29Mn–0.3C steel in different material states. 相似文献
65.
Wideband LC balun transformer using coupled LC resonators embedded into organic substrate 总被引:1,自引:0,他引:1
Jong Cheol Park 《Microelectronics Journal》2009,40(11):1555-1560
In this paper, wideband LC balun using coupled LC resonator has been newly designed, simulated, and fabricated. The proposed balun has a novel scheme which consists of two pairs of coupled embedded LC resonators which share one resonator with each other. The coupled resonators are applied to provide a precise phase difference of 180° and an identical magnitude between two balanced ports and DC isolation characteristic with impedance transformation. Furthermore, proposed resonators have relatively small inductance values which can be easily embedded into the organic package substrate. In order to reduce the size of embedded capacitors, BTO composite high dielectric film was applied to increase their capacitance densities. The measured results of fabricated wideband balun exhibited an insertion loss of 1.8 dB, a return loss of 10 dB, a phase imbalance of 0.5°, and magnitude imbalance of 0.7 dB at frequency bandwidth of 700 MHz ranged from 1.8 to 2.5 GHz, respectively. They agreed well with the simulated ones. The fabricated balun has a relatively small volume of 2 mm×3.5 mm×0.66 mm (height). 相似文献
66.
《Food Control》2016
A simple and rapid multi-class multi-residue analytical method was developed for the screening and quantification of veterinary drugs in royal jelly by ultra performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS). A total of 90 veterinary drugs investigated belonged to more than 14 families such as lincomycins, macrolides, sulfonamides, quinolones, tetracyclines, β-agonists, β-lactams, sedatives, β-receptor antagonists, sex hormones, glucocorticoids, nitroimidazoles, benzimidazoles, nitrofurans, and the others. A modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) procedure was used for the sample preparation without solid-phase extraction step. The linearity, sensitivity, accuracy, repeatability, and reproducibility of the method were fully validated. The response of the detector was linear for each target compounds in wide concentration range (at least, two orders of magnitude) with correlation coefficient (R2) of 0.9921–0.9999. The range of the limit of quantification for these compounds in the royal jelly ranged from 0.21 to 20 μg/kg. The repeatability and reproducibility were in the range of 3.01–11.6% and 5.97–14.9%, respectively. The average recoveries ranged from 70.21 to 120.1% with relative standard deviation of 1.77–9.90% at three concentration levels. For the screening method, the data of the precursor and product ions of the target analytes were simultaneously acquired under the All Ions MS/MS mode in a single run. A homemade database including the elemental composition, accurate masses, retention time, isotopic pattern data of the target ions the characteristic in-source fragment ions was utilized for the confirmation and identification of the target compounds. The applicability of the screening method was verified by applying to real royal jelly samples, and certain veterinary drugs were detected in some cases. 相似文献
67.
Chun Lu Guorong Wang Yan Li Liebing Zhang 《International Journal of Dairy Technology》2013,66(3):325-332
The objective of this study was to investigate the effects of homogenisation pressures (10, 20, and 30 MPa) on the physicochemical changes in top, middle and bottom layers of ultra‐high temperature whole milk stored at 25 °C for 6 months. Fat separation, fat globule sizes, fat and protein contents, viscosity, free amino acids content and pH were analysed at an interval of 15 days. Results showed that higher homogenisation pressure retarded the differentiations of milk fat globule sizes, fat and protein contents and viscosity in different milk layers, but did not affect the final fat separation, proteolysis and pH. 相似文献
68.
A phaser-based processing technique was adopted in an UWB over fiber system employing SOA. The target is to simultaneously reduce the ASE noise impact and nonlinear effects inherent to optical amplification. Experimental results prove the effectiveness of chirping in terms of cross correlation and bit error rate. 相似文献
69.
本文结合东北地区伊敏-齐齐哈尔冯屯变电站500kV输电工程提出了500kV等级串联电容补偿站的通用设计。设计中的主要技术为“积木式”构思,即用典型单元装配成不同参数的串补站,便于通用、制造与维护。本设计中采用的扩大的典型单元使辅助设备减少了几乎一半。新一代的ZnO保护装置,提高了串补站的性能。双回线中串补站的新型主结线方式,可以使串补站的电容器容量减少一半,就伊敏-冯屯串补站而言,可节省基建投资近5000万元。本文所述的典型单元除对地绝缘外也可用于任何电压等级(750~1200kV)。 相似文献
70.
超宽带(UWB)通信技术 总被引:5,自引:19,他引:5
本文介绍了超宽带技术的基本概念和主要特点,目前主要的研究方向.国际上超宽带技术的标准化和商业化进展。 相似文献