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Yishu XU Xiaowei LIU Jiuxin QI Tianpeng ZHANG Minghou XU Fangfang FEI Dingqing LI 《Frontiers in Energy》2021,15(2):449
Recognizing the nature and formation progress of the ash deposits is essential to resolve the deposition problem hindering the wide application of large-scale biomass-fired boilers. Therefore, the ash deposits in the superheaters of a 220 t/h biomass-fired CFB boiler were studied, including the platen (PS), the high-temperature (HTS), the upper and the lower low-temperature superheaters (LTS). The results showed that the deposits in the PSs and HTSs were thin (several millimeters) and compact, consisting of a yellow outer layer and snow-white inner layer near the tube surface. The deposits in the upper LTS appeared to be toughly sintered ceramic, while those in the lower LTS were composed of dispersive coarse ash particles with an unsintered surface. Detailed characterization of the cross-section and the initial layers in the deposits revealed that the dominating compositions in both the PSs and the HTSs were Cl and K (approximately 70%) in the form of KCl. Interestingly, the cross-section of the deposition in the upper LTS exhibited a unique lamellar structure with a major composition of Ca and S. The contents of Ca and Si increased from approximately 10% to approximately 60% in the deposits from the high temperature surfaces to the low temperature ones. It was concluded that the vaporized mineral matter such as KCl played the most important role in the deposition progress in the PS and the HTS. In addition, although the condensation of KCl in the LTSs also happened, the deposition of ash particles played a more important role. 相似文献
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用氢直流电弧法制备La-LaH2纳米粉末,再采用放电等离子烧结技术,在原位、"无氧"条件下成功制备高纯LaB6多晶纳米块体热阴极材料,并系统研究放电等离子烧结温度、压强对材料物相、结构和性能的影响.结果表明,材料中形成单相的LaB6,纯度达到99.867%,平均晶粒尺寸为120 nm,LaB6纳米块体相对密度达到99.2%,维氏硬度达到17.4 GPa,抗弯强度高达245.6 MPa,己达单晶材料的理论抗弯强度值. 相似文献
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Jiuxin Jiang Bo Zhu Peiling Wang Weiwu Chen Dongsheng Yan Hanrui Zhuang Yibing Cheng 《Journal of the American Ceramic Society》2005,88(4):950-953
The Pr α-sialon powders prepared by self-propagating high-temperature synthesis (SHS), consisting of 55 wt% Pr α-sialon and 45 wt% of β-sialon (abbreviated as α' and β'), were hot-pressed at 1800°C for 1 h. The results showed that Pr α' phase would transfer to β' with the appearance of JEM phase (Pr(Si6− z Al z )(N10− z O z )) after sintering, thus resulting in the increase of β' phase to 86 wt%. The addition of Y2 O3 into SHS-ed Pr α' powders as the starting materials restrains the transformation of α' to β' and prevents the formation of JEM phase as well. The nucleation mechanism of Pr α' grain during hot-pressing was investigated in terms of transmission electron microscope and energy-dispersive spectrometer analysis. Two nucleation modes of Pr α' grains were found, i.e., nucleating on the undissolved Pr α' grains and on the nuclei of (Pr, Y) α' grains precipitated from liquid phase. 相似文献
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近年来,我厂甜菜收购总量已超过计划总量的114.3%,甜菜保藏期要延长110天以上。为减少甜菜保藏损失,我们进行了暖甜菜保藏技术应用的研究,同时进行了试验示范。此项技术可使暖甜菜堆表面相对湿度达70%,堆内温度在0~5℃。经1991—1992两年的试验,暖甜菜保藏比常规保藏甜菜还原糖少增加0.085%,根重损失平均降低了2.48%,糖量损失平均减少1.88%。 相似文献
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With the appearance of application, such as VoIP and VOD, traditional best-effort service of network cant meet the needs of these applications. This paper proposes a QoS management and control architecture for Intranet, through which guaranteed services of network can be implemented in Intranet. In this architecture, there is a QoS control server, which is responsible for QoS control and management,while the router forwards packets according to the command from it. 相似文献
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HPLC/UV analysis of chlorfenapyr residues in cabbage and soil to study the dynamics of different formulations 总被引:4,自引:0,他引:4
The chlorfenapyr analysis method of residue, its degradation and final residue in soil and cabbage were studied. Residues of chlorfenapyr were extracted from soil and cabbage with acetone/water, purified by liquid/liquid partition and chromatographic column, concentrated to a small volume, and then determined by HPLC equipped with UV detector. The mean accuracy of analytical method were 93.3% and 90.6% in soil and cabbage, respectively; the precision (repeatability) in cabbage ranging from 1.7% to 11.8%, in soil ranging from 2.8% to 11.2%; the precision (reproducibility) in cabbage ranged from 2.2% to 12.1%, in soil it ranged from 2.4% to 11.5%. The minimum detectable amount of chlorfenapyr was 0.65 ng, the minimum detectable concentration was 0.0162 mg kg-1. The degradation of chlorfenapyr formulations in soil and cabbage was determined. The results showed that chlorfenapyr nanoformulation and suspension concentration degradation in soil coincided with C=0.2538 e-0.1612t, C=0.537 e-0.1754t, respectively; the half-lives were about 4.3 d and 3.9 d, respectively. Two kinds of chlorfenapyr formulation degradation in cabbage coincided with C=4.0431 e-0.3103t, C=6.9611 e-0.2686t respectively; the half-lives were about 2.2 d and 2.6, d, respectively. When chlorfenapyr formulations were applied according to the double recommended dose, the final residues in cabbage were much lower than the USA EPA's maximum residue limit of 1 mg kg-1 in vegetables. The degradation rate of chlorfenapyr nanoformulation was faster than that of suspension concentration, and the former residue was also less in soil. Therefore, a harvest interval should be more than 5 d, and a dosage of 900 mL/hm2 was suggested for chlorfenapyr suspension concentration, which could be considered as safe to human beings and animals. Chlorfenapyr nanoformulation was safer than suspension concentration, its harvest interval and dosage can attain a high level. 相似文献
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在分析现有社区划分算法的基础上,针对当前算法Q值有偏及权值未体现等缺陷,提出了一种基于无偏Q值反馈的社区划分算法.该算法首先利用传递权值计算出节点间的相似度;然后,采用随机游走策略确定最优社区数,以解决现有划分算法中Q值有偏的问题;最后,在最优社区数确定的情况下,利用划分结果评价Q值反馈更新信息素矩阵以驱动后续的划分,从而达到快速收敛的目的.针对计算机构造的数据集以及实际网络的实验分析结果表明,与现有算法相比,该算法在社区划分方面具有更高的准确率及更快的收敛速度,能够达到社区划分以及核心节点发现的目的,可被推广应用至移动社会网络模型的建立中. 相似文献
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