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91.
ABSTRACTImproving the hydration resistance of CaO particle in manufacturing and application of free CaO-containing materials has practical significance. In this study, CaO granules was made from Ca(OH)2 particles, which were fabricated by the granulation method. The results showed that the hydration resistance of the CaO granules which was prepared under 1700?r?min?1 was the best, the CaO granules was sintered well in calcination process, the shell of CaO granules was relatively dense, which improves the hydration resistance of CaO granules, and the rate of hydration weight increment was 0.58% after placed in the air for 20 days under a temperature of 10–14°C and a relative humidity of 57–81%. 相似文献
92.
Peng Jiang Jiafeng Lu Kun Li Xiquan Chen Ruiqi Dan 《Fullerenes, Nanotubes and Carbon Nanostructures》2020,28(5):381-386
AbstractPreparation condition can affect the structure and the properties of nanofiber membrane. In order to explore suitable conditions to prepare the Fe3O4/PVDF nanofiber membrane with good hydrophobicity, the hydrophobicity of Fe3O4/PVDF nanofiber membranes obtained by electrospinning was investigated by changing preparation conditions like weight percentage of Fe3O4 nanoparticles, blending quality concentration of poly (vinylidene fluoride) (PVDF) and Fe3O4 nanoparticles, and positive voltage. And the variations of hydrophobicity of Fe3O4/PVDF nanofiber membranes modified by 1H, 1H, 2H, 2H-perfluorodecyl trimethoxysilane were studied. The results show that the hydrophobicity of Fe3O4/PVDF nanofiber membranes has changed under different preparation conditions. The contact angles of samples increased after a modification by 1H, 1H, 2H, 2H-perfluorodecyl trimethoxysilane, which indicates that the hydrophobicity of Fe3O4/PVDF nanofiber membranes has been enhanced. 相似文献
93.
This paper investigates the N-policy M/M/1 queueing system with working vacation and server breakdowns. As soon as the system becomes empty, the server begins a working vacation. The server works at a lower service rate rather than completely stopping service during a vacation period. The server may break down with different breakdown rates during the idle, working vacation, and normal busy periods. It is assumed that service times, vacation times, and repair times are all exponentially distributed. We analyze this queueing model as a quasi-birth–death process. Furthermore, the equilibrium condition of the system is derived for the steady state. Using the matrix-geometric method, we find the matrix-form expressions for the stationary probability distribution of the number of customers in the system and system performance measures. The expected cost function per unit time is constructed to determine the optimal values of the system decision variables, including the threshold N and mean service rates. We employ the particle swarm optimization algorithm to solve the optimization problem. Finally, numerical results are provided, and an application example is given to demonstrate the applicability of the queueing model. 相似文献
94.
为有效提高功能性茶浓缩反渗透膜的回收效率和抗污性能,探究了3种介孔分子硅材料(MCM-41、SBA-15和MCFs)对浓缩膜面聚酰胺层聚合形成过程的结构影响。结果表明,添加质量分数0.02%经磺化预处理的MCM-41于间苯二胺水相可接枝酰氯基团,形成的聚酰胺结构层峰谷粗糙跨度仅为220 nm且交联紧致,膜抗拉伸强度增加37.8%;SBA-15和MCFs相膜面峰谷跨度达500~780 nm,横向褶皱和团聚,结构存在孔道塌陷;改性膜在3 h内对茶多酚、茶多糖、茶蛋白即可达到最大浓缩度,减少50%浓缩时间;MCM-41和SBA-15膜长时间运行的浓缩降率仅为2.8%~6.1%,48 h下降率比显示改性膜达标使用时长增加112.5%~137.5%,亲水性和抗污堵能力均大幅提升,可有效满足功能化茶浓缩精度。 相似文献
95.
使用单层纳米氧化石墨烯(NGO)粒子对环氧树脂进行改性处理,采用真空辅助树脂传递模塑成型工艺制备了[±45/0/90]2S铺层角度下的纯树脂及单层NGO改性碳纤维复合材料(CFRP)层合板。通过落锤冲击试验、超声C扫描检测、冲击后压缩试验等对纯树脂及单层NGO改性CFRP进行实验研究。结果表明,纯树脂及单层NGO改性CFRP在损伤阻抗及损伤容限实验中均存在拐点现象,且拐点出现在相同深度位置,其中纯树脂CFRP拐点位置为0.51 mm,单层NGO改性CFRP拐点位置为0.43 mm;相对于纯树脂CFRP,单层NGO改性CFRP可以显著提高复合材料的抗冲击性能及冲击后的压缩性能;通过对冲击后凹坑深度及凹坑面积进行数据模拟,可以用拟合公式实现对复合材料的损伤预测。 相似文献
96.
Design and Fabrication of Concentration‐Gradient Generators with Two and Three Inlets in Microfluidic Chips 下载免费PDF全文
A simple and low‐cost method for designing and fabricating concentration‐gradient generators with two and three inlets is proposed which can generate different concentration gradients at varying flow velocities. The microchannel structure was designed in S‐shape and left‐right symmetry. The concentration‐gradient generator was simulated based on the finite element method. The microchannels were processed on a computer numerical control (CNC) engraving and milling machine on poly(methylmethacrylate) substrate, and then two concentration‐gradient generators were fabricated by hot bonding technology. The results of experiment and simulation were compared to prove the feasibility of the method. Flow velocity was an important factor for generating different concentration gradients. The concentration‐gradient profiles of the generators with two and three inlets present approximately linear and quadratic curves. 相似文献
97.
《Food Control》2015
A diverse range of genetic elements has been used to develop genetically modified organisms (GMOs) over the last 18 years. Screening methods that target few elements, such as the Cauliflower Mosaic Virus 35S promoter (P-35S) and Agrobacterium tumefaciens nopaline terminator (T-nos), are not sufficient to screen GMOs. In the present study, a multiplex PCR system for all globally commercialized GM soybean events was developed to easily trace the events. For this purpose, screening elements of 24 GM soybean events were investigated and 9 screening targets were selected and divided into three individual triplex PCR systems: P-35S, ribulose-1,5-bisphosphate carboxylase small subunit promoter of Arabidopsis thaliana, T-nos, T-35S, pea E9 terminator, open reading frame 23 terminator of A. tumefaciens, proteinase inhibitor II terminator of potato, acetohydroxy acid synthase large subunit terminator of A. thaliana, and the revealed 3′ flanking sequences of DP-305423-1. The specificity of the assays was confirmed using thirteen GM soybean events as the respective positive/negative controls. The limit of detection of each multiplex set, as determined using certified reference materials of specific GM events, ranged from 0.03 to 0.5%, depending upon target. Furthermore, 26 food samples that contained soybean ingredients, which were purchased from the USA, China, Japan, and Korea, were analyzed, 17 of which contained one or more GM soybean events. These results suggest that the developed screening method can be used to efficiently track and identify 24 GM soybean events in food and feed. 相似文献
98.
99.
The aim of the study was to identify the importance of individual food product attributes (the use of preservatives, processing method, shelf-life period and nutritional value) as well as their relation to the purchase behaviour. To achieve this, consumer preferences were decomposed in conditions of full access to information, and data was compared with actual consumer behaviour related to making purchasing decisions in front of the store shelf. Based on data from 338 respondents, conjoint analysis and repeated ANOVA measurements were carried out, allowing to eliminate individual behavioural patterns. The results showed a dissonance between the consumers attitudes towards the attributes and their shopping behaviour. The processing method was the most important declared attribute for consumers, meanwhile this information was the least searched for during purchase. At the same time, shelf-life period marked as the least important was the main information searched for by consumers when shopping. The results also show a clear dislike towards the use of microwaves as a preservation method, while traditional thermal preservation was marked as the most positive for consumers. In addition, consumers were classified into 3 heterogeneous groups, identifying differences in the preferences of food attributes. The obtained results have practical value relating not only to the preferences of individual attributes, but also to their various variants. The results can be a guide for companies to properly label food products. The indicated dissonance illustrates the educational gap and related insufficient motivation to get to know the product before buying it. This is extremely important in connection with technological development and new food processing methods. 相似文献
100.