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排序方式: 共有1358条查询结果,搜索用时 15 毫秒
81.
82.
This paper aims to evaluate the cylinder head carbon deposit from diesel engine fuelled by four samples of diesel fuel emulsions containing 0%; 5%; 10% and 15% vol. water and 20% Palm Oil Methyl Ester (POME) were subjected to thermogravimetric analysis (TGA/DSC) in air medium. The deposit build up processes were performed on a single-cylinder direct-injection diesel engine for period of 25 h for each set of test fuel under constant speed 2500 rpm. The TGA system was used and then correlated with elemental analysis as well as infrared spectra for microscopic observations. It has been found that, as the water increases in fuel, less aromatic and less reactive of deposits would be formed. Therefore, such method of analyses can be used as an indicator to verify the stability of carbon deposit inside the combustion chamber that could substantiate the applicability of a particular fuel to be accepted. 相似文献
83.
以频那酮和过量的碳酸二甲酯为原料在二甲苯溶液中,经一步反应,制得了纯度99%以上的特戊酰乙酸甲酯,对合成条件进行了探讨,确定原料配比(频那酮/碳酸二甲酯)为1:5.0,反应温度为120℃,催化剂用量(甲醇钠/频那酮)为1:5:1。在优化条件下,产品的收率(以频那酮计)达77.4%。 相似文献
84.
Augustine E. Ofomaja Emmanuel E. UkpeborStephen A. Uzoekwe 《Biomass & bioenergy》2011,35(10):4112-4123
Determination of the overall rate controlling step in the biosorption of Methyl violet dye onto a new biosorbent, palm kernel fiber has been determined. Pseudo-second-order model described the kinetics over the whole contact time period for the effect of initial concentration and temperature. Using the Wu’s approaching equilibrium factor, Rw, it was observed that the time for the switch from initial biosorption to intraparticle diffusion is affected by initial concentration and temperature. A comparison between the activation parameters of film diffusion, pseudo-second order ion exchange and intraparticle diffusion revealed that film diffusion is the overall slowest step in the biosorption process. Temperature increased the biosorption capacity but reduced slightly the rate of intraparticle diffusion, indicating that the biosorbent surface was activated by temperature which limited the diffusion of Methyl violet molecules into the interior of the biosorbent. A multistage process design to minimize mass and contact time was done. 相似文献
85.
Chiranjeeva Rao Seela B. Ravisankar 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2018,40(21):2564-2571
This work investigates the suspension duration of the nanosized multiwalled carbon nanotubes (MWCNT) and aluminum oxide (Al2O3) in B20, B50 and B70 blends of Jatropha Methyl ester. The MWCNT and aluminum oxide (Al2O3) are added to the fuel blends in the proportions of 50 and 100 pmm separately by ultra sonication. The prepared fuel samples are characterized, and turbidity analysis was done to find the stability rate of nano-additives. The outcomes reveal the maximum stability rate for MWCNT and Al2O3 as 83.3% and 87.03%, respectively, with 50ppm in B20 over a period of eighteen days. A considerable drop in suspension was observed with the 100 ppm MWCNT and Al2O3 biodiesel blends. 相似文献
86.
《国际聚合物材料杂志》2012,61(5):395-404
Vibrational spectra of a series of Methyl Acrylate/Ethyl Acrylate (MA/EA) copolymers, synthesized at 60°C and 70°C for 5 different MA/EA compositions for each temperature, were obtained by FT-Raman spectroscopy. An inversion of the symmetric and antisymmetric stretching vibrations of the CH3 group, due to the mobility of this group, was found. By analyzing the acoustical and optical branches of the spectra, the mobility of the backbone structure was also determined. The EA homopolymer was found to posses the highest conformational order. 相似文献
87.
Silvia Mendona Vieira Tarliane Maria Silva Maria Beatriz Abreu Glria 《Food chemistry》2010,119(1):7-11
The influence of processing on the levels of bioactive amines and proline as well as on some physico-chemical characteristics of concentrated orange juice was investigated. Samples were collected at seven points of a production line on three non-consecutive days, and analysed for the levels of 12 bioactive amines, proline, and reducing and non-reducing sugars, and for some physico-chemical characteristics. Among the amines analysed, only putrescine, spermidine and synephrine were found in the samples at all processing stages. Significant differences were observed for spermidine and total amine levels throughout processing. Synephrine and putrescine were resistant to processing. Proline levels changed significantly throughout processing, as did levels of reducing and non-reducing sugars. The pH varied from 3.59 to 3.72, acidity from 0.873 to 0.918 g citric acid/100 mL, and density from 1.0378 to 1.0970 g/mL. Among these parameters, pH, acidity and density were significantly affected by processing. 相似文献
88.
桔皮酱的研制 总被引:1,自引:0,他引:1
顾镕 《浙江工业大学学报》1989,(3)
桔皮含有丰富的果胶和适量的有机酸,是生产果酱的理想原料。本文介绍了以桔皮为原料,经脱苦、脱涩、漂洗、磨酱、混配和浓缩等处理制成一种具柑桔特有的芳香风味,美味可口的桔皮果酱。 相似文献
89.
Dae Sung Yoon Yoon-Kyoung Cho Kwang W. Oh Sunhee Kim Young Ah Kim Jung Im Han Geunbae Lim 《Microsystem Technologies》2006,12(3):238-246
We have fabricated a microfluidic gel valve device that used reversible sol–gel transition of methyl cellulose (MC). A microheater
and a microtemperature sensor were implemented in each microchannel in the gel valve device. Before evaluating the performance
of the gel valve device, various properties of the MC solution were investigated using viscometer, spectrophotometer, and
NMR. Gelation temperature was increased as the MC concentration was increased. Clear gel, an intermediate state between clear
sol and turbid gel, was found at the temperature range from 30–40°C to 50–60°C. Temperature at each microchannel of the device
was measured and the effect of the temperature difference on the valve operation was elucidated. In order to have normal operation
of the gel valve, it was important to keep the temperature of the heated microchannel around 60°C while keeping the temperature
of the flowing microchannel below 35°C. The temperature difference between two microchannels was about 23 K when fan forced
cooling (FFC) method was used. For normal performance of the gel valve device, a temporary pause of fluid flow for at least
5 s was required to complete the local gelation in the microchannel. Stable gel valve performance was obtained at the flow
rates larger than 5 μl/min. The gel valve device showed no leakage up to 2.07×104 Pa. 相似文献
90.
The glassy carbon electrode coated with electropolymerized methyl-red film, 1.2 × 10−6 m in thickness, (PMRE) showed high sensitivity towards Hg(II) ions. PMREs were adopted to accumulate and detect Hg(II) ions in a pH 2.56 Britton–Robinson buffer solution. Cyclic voltammogram of the accumulated Hg species on PMREs exhibited an anodic wave at 0.64 V and a cathodic wave at 0.13 V, due to the oxidation of accumulated Hg species on PMREs and the reduction of Hg(II) ions in the solution, respectively. For this heterogeneous adsorption of Hg(II) ions onto PMREs, the maximum surface concentration, adsorption equilibrium, and Gibbs energy change were evaluated to be 5.12 × 10−6 mol m−2, 3.7 × 105 l mol−1, and −30.1 kJ mol−1, respectively. The anodic peak current at 0.64 V was linear with the concentration of Hg(II) ions in the range of 1.1 × 10−10 to 1.1 × 10−7 M with a detection limit of 4.4 × 10−11 M. The proposed method was utilized successfully for the detection of Hg(II) ions in the lake water. 相似文献