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排序方式: 共有178条查询结果,搜索用时 31 毫秒
21.
Microwave freeze drying (MFD) normally contains three stages, i.e., pre-freeze stage, primary drying stage and secondary drying stage, just as in conventional freeze drying. This research examines the variations of structure, starch content, reducing sugar content, color change as well as expansion ratio during these stages of microwave freeze drying banana chips. Results show that biggest changes are found at the primary drying stage in the banana slices’ starch content, reduced sugar content, their structure and their changed colors while the biggest change of expansion ratio occurs at the secondary drying stage. Similar results can also be obtained for FD samples. Thus it is concluded that the primary stage can do most damage to the banana chips. 相似文献
22.
介绍了湖北华电黄石发电股份有限公司使用的Powerflex 7000中压变频器的总体情况和特点,说明中压变频技术在电厂送风机上有广泛应用前景. 相似文献
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Evaluation of apple texture with contact acoustic emission detector: A study on performance of calibration models 总被引:1,自引:0,他引:1
Artur Zdunek Justyna CybulskaDorota Konopacka Krzysztof Rutkowski 《Journal of food engineering》2011,106(1):80-87
Performance of calibration models for evaluation of apples sensory texture with contact acoustic emission detector (CAED) was studied. For model evaluation and testing, 2500 apples of 19 cultivars were harvested over two seasons. Apples were stored at normal atmosphere (NA), controlled atmosphere (CA) for different periods or were treated with 1-methylcyclopropene (1-MCP) in order to obtain a high variability of texture and fruit maturity. Apples were tested simultaneously in two distinct laboratories. The models were created and validated on averaged values from 10 fruits using simple linear regression, multiple linear regression (MLR) and principal component regression (PCR). Performance statistics of the models were expressed in terms of determination coefficient (R2), root mean square errors of cross validation (RMSECV) or prediction (RMSEP) and ratio of prediction to deviation (RPD). Firmness and total acoustic emission counts were predictors of sensory texture in the models. MLR and PCR models show better performance for prediction of sensory data than simple linear regression models however PCR models show the best results among models tested in this study. Common PCR models for several cultivars allow for successful prediction of hardness (RPD > 2.0), crispness and overall texture (1.5 < RPD < 2.0). The single-cultivar PCR models, constructed on data sets containing 26-39 averaged values, reveal significantly better performance (RPD > 2.0 for most of the cases) than the common PCR models for many varieties. 相似文献
25.
Ying Wang Yuangang Zu Jingjing Long Yujie Fu Shuangming Li Dongyang Zhang Ji Li Michael Wink Thomas Efferth 《Food chemistry》2011
An enzyme incubation–water extraction (EI–WE) method was developed and optimised for the extraction of the natural antioxidant taxifolin and of the total flavonoids from wood sawdust of Larixgmelini (Rupr.) Rupr. A factorial design and a central composite design approach were used for method optimisation. Optimal conditions were 0.5 mg/ml cellulase and 0.5 mg/ml pectinase, a pH of 5.0, a temperature of 32 °C and 18 h incubation time. The flavonoids and taxifolin were extracted in hot water at 50 °C for 30 min, with a solid to liquid ratio of 1:20. Under optimised conditions, the yields of taxifolin and total flavonoids increased from 1.06 ± 0.08 to 1.35 ± 0.04 mg/g and 4.13 ± 0.17 to 4.96 ± 0.29 mg/g, respectively. DPPH and BHT assays revealed that the EI–WE samples had 1.8- and 1.68-fold higher antioxidant activities than the controls. SEM results revealed the structural disruption of wood sawdust with enzyme incubation. 相似文献
26.
In this work we propose an optimal back plane biasing (OBB) scheme to be used in a UTBB FD SOI technology that minimizes the energy per operation consumption of sub threshold digital CMOS circuits. By using this OBB scheme, simulations show that more than 30% energy savings can be obtained with low threshold voltage (LVT) devices in comparison with classic symmetric back plane biasing (SBB) schemes. Additionally, this OBB scheme allows to adjust the performance of the circuit with very small energy penalties. A very simple and intuitive model, for sub threshold digital CMOS circuits, was developed to justify the benefits obtained by OBB. The results predicted by the model are confirmed with extensive simulation results. We show that the OBB approach can be applied easily to a given circuit just based on the information provided by a logic simulation of the circuit (or even an analysis of its structure) and simple electrical simulations of the pMOS and nMOS transistors. Finally, we show that the variability in the energy consumption is improved by using OBB and suggests that new sizing methodologies must be studied to fully benefit from the wide back plane voltage range available in UTBB FD SOI technology for the design of robust energy efficient digital circuits. 相似文献
27.
Eskandar Moghimipour Mohsen Rezaei Maryam Kouchak Jafar Fatahiasl Kambiz Ahmadi Angali Zahra Ramezani 《Drug development and industrial pharmacy》2018,44(5):861-867
The aim of the present research was to evaluate the impact of coating layers on release profile from enteric coated dosage forms. Capsules were coated with Eudragit FS 30D using dipping method. The drug profile was evaluated in both phosphate buffer and Hank’s solutions. Utilization X-ray imaging, gastrointestinal transmission of enteric coated capsules was traced in rats. According to the results, no release of the drug was found at pH 1.2, and the extent of release drug in pH 6.8 medium was decreased by adding the coating layers. The results indicated single-layer coated capsules in phosphate buffer were significantly higher than that in Hank’s solution. However, no significant difference was observed from capsules with three coating layers in two different dissolution media. X-ray imaging showed that enteric coated capsules were intact in the stomach and in the small intestine, while disintegrated in the colon. 相似文献
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Hoyer H Föger F Kafedjiiski K Loretz B Bernkop-Schnürch A 《Drug development and industrial pharmacy》2007,33(12):1289-1296
Within this study, a novel gastrointestinal patch system was developed and investigated regarding water-absorbing capacity, adhesive properties, in vitro release, unidirectional release and permeation enhancing effect. Water uptake studies revealed that the weight of patch systems with Ch-GSH increased about 44.5 ± 2.3 mg (127%) after 90 min. This patch system remained even after 180 h on the mucosa and released 49.7 ± 0.7% of FD4 within 8 h. A 2.5-fold higher transport of FD4 can be obtained in contrast to control. In conclusion this patch system could be an interesting possibility for the transport through the intestinal mucosa of macromolecules which will normally be degraded in the intestinal tract. 相似文献
30.
李恩家 《信息工程大学学报》1999,(1)
本文对多载波频率分集扩展频谱多址系统(FD/SSMA)支持多速率业务的问题进行了研究。文中首先回顾了现有的几种支持多速率业务的设计方案,然后分析了离散Walsh函数的正交特性,在此基础上提出了一种基于FD/SSMA系统的可变处理增益多速率传输的设计方案,并对该方案的功率谱密度特性进行了分析。 相似文献