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Xueqin Song Shiru Le Xiaodong Zhu Long Qin Yan Luo Yanwei Li Kening Sun Ying Chen 《International Journal of Hydrogen Energy》2017,42(24):15808-15817
Bi2O3 doped BaFeO3?δ on the B-site as a cobalt free perovskite cathode for intermediate temperature solid oxide fuel cells is evaluated. The BaFe1?xBixO3?δ (BFBx) powders are synthesized by solid state reaction. It is found that Bi2O3 doping stabilizes the BaFeO3 cubic phase. The new cathode is compatible with Gd0.1Ce0.9O1.95 even calcined at 1000 °C for 10 h. The electronic conductivity shows a transformation from semiconductor to metal conductor, and achieves its maximum value of 28.1 S cm?1 for BFB10 at 800 °C. The δ is as high as 0.408 for BFB10 determined by iodometric titration. This leads to the free volume in crystal lattice of BFB10 21.60% higher than that of BaNb0.05Fe0.95O3?δ. The area specific resistance is only 0.133 Ω cm2 for BFB10 at 750 °C and the average TEC is 26.697 × 10?6 K?1 measured from room temperature to 800 °C. The peak power density of Ni-YSZ|YSZ|GDC|BFB10 cell is 646.28 mW cm?2 at 750 °C, higher than that of single cell using LSCF as cathode. These show that BFBx perovskite oxides with cubic phase are promising cathodes for intermediate temperature solid oxide fuel cells. 相似文献
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针对富含CO2的高温高压油气井中水泥环的腐蚀问题,进行了高温高密度防腐水泥浆体系加重剂的研究,并对比了相同粒度的锰矿粉、赤铁矿和重晶石3种加重剂对水泥浆性能的影响,在150 ℃、CO2分压20 MPa的环境下进行了腐蚀实验。研究结果表明,锰矿粉水泥浆需水量最少,相同条件下具有较好的流变性和较低的失水量;锰矿粉水泥石腐蚀后渗透率最小,抗压强度较高;腐蚀30 d后,锰矿粉水泥石腐蚀深度最低,重晶石水泥石的腐蚀深度约为锰矿粉水泥石的1.5倍;腐蚀后锰矿粉水泥石结构最致密,腐蚀后生成物的特征峰最低;锰矿粉加量为25%、50%和75%的3种水泥石腐蚀27 d后,加量为50% 的水泥石腐蚀深度最小。与赤铁矿和重晶石相比,锰矿粉为较好的选择,但加量过多时会对水泥浆防腐蚀性能产生不利影响。 相似文献
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针对规模化风电并网对系统调频造成的不确定性问题,提出了一种计及风电不确定性的云模型负荷频率控制策略。首先将风电出力作为扰动信号,与联络线功率偏差组成的区域控制偏差作为负荷频率控制器的输入量,根据云模型规则发生器建立了具有不确定性映射关系的云(比例-积分,PI)负荷频率控制器。以含有风电的三区域互联电网为例,通过某区域电网实测运行数据仿真分析表明,所建立的云PI控制器能够较好地跟踪风电功率波动,具有较强的抗干扰性。所提方法不仅满足了风电接入对电网调频的要求,而且控制效果明显优于传统PI控制器。 相似文献
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针对高职院校校园网络目前存在的安全隐患,提出了构建高职院校校园网络安全防护体系的解决技术与方案,保障校园网安全、稳定高效运行。 相似文献
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随着时代的发展,Interact日益普及,网络已经成为信息资源的海洋,给人们带来了极大的方便。但由于Interact是一个开放的,无控制机构的网络,经常会受到计算机病毒、黑客的侵袭。它可使计算机和计算机网络数据和文件丢失,系统瘫痪。因此,计算机网络系统安全问题必须放在首位。本文介绍了计算机系统安全的维护措施,给计算机网络工作人员有一定帮助。 相似文献
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干酪成熟过程中蛋白质的水解是风味形成的重要途径。在中国自由放养和小规模奶牛养殖仍占有一定比例,这其中的手动挤奶方式会导致原料乳中含有一定数量具有蛋白酶活性的体细胞,影响干酪成熟及风味。目前关于体细胞通过蛋白水解作用对脱脂干酪挥发性风味物质的影响尚未明确。本研究选取3 种不同体细胞数的原料乳,解析体细胞的细胞组成并制作脱脂干酪,在90 d的干酪成熟期中测定干酪的蛋白酶活性、蛋白水解水平、成熟后干酪的挥发性风味物质组成及其质构特性,评价不同体细胞数、干酪的蛋白质水解程度及其对干酪风味和品质的影响。结果表明:体细胞数越高的干酪蛋白酶活性越高,αs2酪蛋白水解程度越高,对干酪风味和质构也有不同程度的影响;使用体细胞数适量增加的原料乳(10×104~30×104 个/mL)有利于干酪风味的形成;中等体细胞数组中干酪特征风味物质3-羟基-2-丁酮含量最高(34.57%),是低体细胞数组含量(28.64%)的1.2 倍、高体细胞数组含量(20.72%)的1.6 倍;原料乳中过多体细胞(多于86×104 个/mL)则会导致干酪过度水解并产生不良风味,高体细胞数组中检测到会引起不良风味的风味物质如辛醛、壬醛、仲辛酮、己醛。 相似文献
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为达到烟气超低排放目的,神华国华三河发电有限责任公司300 MW亚临界自然循环燃煤机组实施了一系列改造项目,如低氮燃烧器改造,SCR脱硝改造,新增低低温省煤器,静电除尘器高频电源改造,湿法脱硫塔脱硫提效并增加管式除雾器,新增湿式静电除尘器等。为研究超低排放改造后脱硫废水及湿式静电除尘器废水中汞浓度变化,以该机组为研究对象,取样分析了脱硫塔、湿式电除尘器补充水及排放废水中汞含量。研究结果表明:由于燃煤、石灰石及补充水中汞含量较低,实验期间该超低排放改造电厂脱硫废水及湿式电除尘器废水中汞含量均较低,分别为0.140~0.468 μg/L和0.094~0.102 μg/L;脱硫塔所排52 m3/h废水中汞增加量为1.75~5.50 mg;湿式电除尘器所排废水中汞含量没有明显变化。 相似文献
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Shilei Chen Yongke Hou Hao Wang Zheng Zhao Yongqi Zhang Juanyu Yang Xiaowei Huang 《中国稀土学报(英文版)》2021,39(5):587-595
Ceria-zirconia based mixed oxides(CZs) have been applied in three-way catalysts(TWCs) for their high surface area and oxygen storage capacity(OSC).In this work,enhanced thermal stability of Ce_(0.33)Zr_(0.55)(LaNdY)_(0.12)O_2 mixed oxides was realized via a facile and scalable approach,namely,sulfateaided coprecipitation method was labelled as CZ-S.Sulfate ion(SO_4~(2-)) was added into raw solution in the form of sulfuric acid and acted as coordination agent.The control sample was prepared by conventional coprecipitation method without sulfuric acid added and labelled as CZ.The promotion effect of sulfate ion was analyzed systematically by X-ray diffraction(XRD),transmission electron microscopy(TEM),scanning electron microscopy(SEM),N_2 adsorption-desorption,Fourier transform infrared spectroscopy(FT-IR),X-ray photoelectron spectroscopy(XPS),OSC and hydrogen temperatureprogrammed reduction(H_2-TPR) analysis.XRD and high resolution TEM results reveal that CZ-S have homogeneous distributions of elements.TEM and SEM images show that fresh samples of CZ-S have narrower distributions of grain sizes and larger pore sizes than those of CZ.Through cross analysis of structure and morphology of CZ and CZ-S,we find that the introduction of sulfate ions results in uniform distributions of elements,narrows distributions of grain sizes,and enables the formation of secondary loose packing of sub-particles,which lead to enhanced thermal stability of the samples of CZ-S upon aging process at high temperature.After aging treatment at 1100℃ for 10 h,aged samples of CZ-S present larger specific surface areas and pore volumes than the aged sample prepared by conventional coprecipitation method without sulfate ions added.Furthermore,the aged sample of CZ-S2(SO_4~(2-)/Zr=1)possesses the highest specific surface area of 21.9 m2/g and the biggest pore volume of 0.035 mL/g among all aged samples. 相似文献