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991.
实验通过定组成的H2/CO2混合气控制氧分压,在温度为1873 K、1673 K、1473 K,氧分压为1.22×10-8~2.18×10-12 Pa、4.92×10-8~8.79×10-12 Pa的范围内,研究了TiOx-SiO2-MgO 系的析出相.结合XRD和EDS分析并对比汪大亚等人的研究可知,当氧分压较高(PCO∶PCO2=5∶1)时,对于初始成分TiO2∶MgO∶SiO2摩尔比为60∶25∶15的试样,在1873 K 和1673 K 时的析出相为TiO2,在1473 K 时其析出相为MgTi2O5;对于初始成分TiO2∶MgO∶SiO2摩尔比为60∶15∶25的试样,在1873 K时其析出相为TiO2,在1673 K和1473 K时析出相为MgTi2O5.而当氧分压较低(PH2∶PCO2=600∶1、300∶1、150∶1)时,2种不同成分的试样在不同温度下的析出相均为黑钛石,并且随着氧分压的降低,黑钛石中的Mg 含量逐渐减少. 相似文献
992.
Cesar Ovalles Estrella Rogel Harris Morazan Kaidong Chen Michael E. Moir 《Petroleum Science and Technology》2016,34(4):379-385
This work focused on the synthesis and characterization of nonylphenol formaldehyde resins (NPFR) as examples of active molecules for preventing asphaltene precipitation in vacuum residue (VR) and hydroprocessed petroleum samples. The evaluation for the NPFR as asphaltene dispersants was carried out using the on-column filtration technique at room temperature and near process conditions (195°C). The results indicated that NPFR (molecular weight = 900–4800 Da) are active for the reduction of asphaltene content of gravimetrically separated asphaltene solutions and for VR and hydroprocessed samples at room temperature (35°C) and at 195°C. It was found that the activity of NPFR as asphaltene dispersants depends not only on the type of sample (asphaltenes, virgin or processed) but also on the temperature, molecular weight, and concentration. 相似文献
993.
M. A. Assaf M. M. Shadman A. Serajian S. Ahmadi Z. Taherian 《Petroleum Science and Technology》2016,34(17-18):1534-1541
Asphaltene precipitation and subsequent deposition in production tubing and topside facilities present significant cost penalties to crude oil production. Therefore, it is highly desirable to predict their phase behavior and the efficiency of dispersants in preventing or delaying deposition. Very few studies have been carried out on the molecular interactions between asphaltenes and different dispersants. As a result, the mechanisms by which dispersants stabilize asphaltenes are still open to discussion. The authors introduced a new method to characterize asphaltenes in perturbed chain statistical association fluid theory equation of state (EOS; perturbed-chain statistical association fluid theory EOS [PC-SAFT-EOS]) and correctly model the effect of dodecyl benzene sulfonic acid (DBSA) dispersant on the thermodynamic behavior of asphaltenes. Using the filtration method the effect of the ionic dispersant (DBSA) on asphaltene precipitation for different concentrations of n-heptane was measured experimentally, then modeled through PC-SAFT EOS. In the approach only the hard-chain and the dispersion terms are taken into consideration, and PC-SAFT parameters were calculated based on Gonzales et al. (2007) based on molecular weight (Mw) and aromaticity factor (γ). Additionally, the model could correctly predict the amount of asphaltene precipitation upon addition of DBSA dispersant. 相似文献
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997.
ABSTRACT: Protein, lipid, and insolubles (bones, skin, scales, fins, insoluble protein, and more) were recovered from rainbow trout processing by-products by means of isoelectric solubilization/precipitation at basic pH and acidic pH. Isoelectric solubilization/precipitation of the trout processing by-products resulted in the recovery of protein that was higher ( P < 0.05) in essential amino acids (EAAs), non-EAAs, and total EAA/total AA ratio when compared to the processing by-products. Basic pH treatments yielded a higher ( P < 0.05) content of EAAs than the acidic pH treatments. Nutritional quality of the recovered protein was high based on EAAs meeting the FAO/WHO/UNU recommendations for adults. The presence of omega-3 and omega-6 fatty acids (ω-3, ω-6 FAs) and the ω-3/ω-6 ratio in the recovered lipids were similar to the trout processing by-products, indicating that the pH treatments had no effect on these FAs. Ca and P contents of the processing by-products exceeded the recommended dietary allowances (RDA), but Fe and Mg did not. Basic pH treatments yielded protein with the lowest ( P < 0.05) amount of minerals and the highest ( P < 0.05) amount of Ca, P, and Mg in the insolubles when compared to acidic pH. The isoelectric solubilization/precipitation of the processing by-products effectively removed minerals from the recovered protein without removal of the bones, skin, scales, fins, and so on, prior to processing. The results indicated that isoelectric solubilization/precipitation, particularly at basic pH, permitted recovery of high-quality protein and lipids from fish processing by-products for human food uses; also, the recovered insolubles may be used in animal feeds as a source of minerals. 相似文献
998.
影响中国大气降水稳定同位素组成的主要因素分析 总被引:11,自引:0,他引:11
本文根据中国大气降水同位素监测网近几年来(1985~1993年)20多个台站的监测结果,以相关分析的形式,探讨了各种气象要素、地理环境因素,对形成我国大气降水稳定同位素组成的影响机理和结果。给出了中国大气降水稳定同位素月雨量加权平均值区域分布图。 相似文献
999.
结合三盛公黄河特大桥一级阶地富水砂粘土、粘砂土、粉细砂地层中采用井群降水明挖承台施工的方法,介绍了井群降水设计与施工技术。 相似文献
1000.
XIE Yun YANG Ke ZHAO Xu FAN Cungan LI Yiyi Institute of Metal Research Academia Sinica Shenyang China 《金属学报(英文版)》1992,5(4):245-249
Effect of microstructure on the mechanical properties of a precipitation strengtheningFe-Ni-Co based low expansion alloy,Incoloy 907.has been investigated under different heattreatments.The dispersed γ-phase is found to be the principal strengthening phase in thealloy.The microstructure of the alloy with even dispersed fine γ′-phase seems to have the bestmechanical properties.However,it will be worsened if the alloy was aged at some higher tem-perature or overaged to precipitate needle-like ε-phase. 相似文献