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401.
对 2 0 0 MW核供热堆装载模式 (燃料组件布置、可燃毒物棒根数和可燃毒物质量分数配置 )进行了优化。利用模拟退火算法和先进格林函数节块法进行多步燃耗优化计算。引入敏感性系数 ,并通过敏感性分析的方法决定优化参数 ,因此在单目标和多目标优化时均取得了明显的效果。对组件布置和可燃毒物质量分数的优化计算结果表明 ,在不改变原有的富集度和组件类型的前提下 ,与参考值相比 ,优化后的循环长度、功率峰因子和卸料燃耗均有明显的改善。该燃料管理方法不仅可用于低温堆而且也可以推广到压水堆  相似文献   
402.
SBR法处理城市污水过程中氮的去除及转化规律   总被引:4,自引:0,他引:4  
介绍了利用SBR法处理广州地区城市污水过程中氮的去除和转化规律及处理过程中的各种影响因素。在处于好氧阶段的反应过程中,在去除有机物和进行磷的吸收的同时,进行硝化反应并且控制硝化反应进行到亚 硝酸型硝化结束,然后进行缺氧反硝化,以达到脱氮的目的。实验结果表明,在去除有机物的同时,氨氮也有很好的去除效果,在反硝化的过程中,硝化氮被转化成氮气,通过硝化和反硝化,使总氮得到了一定程度的去除。  相似文献   
403.
首先推出了容量公式,然后分析了影响容量的若干因素,并将CDMA系统和GSM系统容量进行了比较。  相似文献   
404.
用元胞动力系统(CDS)格子气方法研究二组分混合化样演化若干特性。主要结果是:(1)元胞自身演化映射f的四种不同选取尽管:宏花样”(“黑白花样”)拓扑结构相似,但“微花样”(“灰度花样”)有明显差异,f2和f4所对应的花样在纯黑与纯白区域都存在更加精细的鱼鳞状结构;(2)双嵌段共聚物二组分不对称(即r≠0.5),在0.4≤r≤0.45范围内出现文献中尚未报道过的“颗粒-条状杂交花样”;(3)首次实施了六方格CDS模型,特别是“叠代过程用六方格,涂色用四方格”,结果表明方六格的确具有各向同性性好,稳定性好等优点;(4)Laplace平均算子《》的不同选取对相变花样影响不大。  相似文献   
405.
406.
Microbial desulfurization of fuel oil   总被引:2,自引:0,他引:2  
Culture conditions of desulfurization microbes were investigated with a bioreactor controlled by computer.Factors such as pH, choice of carbon source, optimal concentrations of carbon, nitrogen and sulfur sources were determined. The addition of carbon in a culture with a constant pH greatly improved the growth of Rhodococcus. Cells and cell debris from microbes rested using a sulfur- specific pathway were used to desulfurize diesel oil treated by hydrodesulfurization (acquired from the Research Institute of Fushun Petroleum with total sulfur level at 205 μg/mL).Strains 1awq, IG, X7B, ZT, ZCR, and a mixture of No. 5 and No. 6, were used in the biodesulfurization process. The reduction of total sulfur was between 10.6% and 90.3%.  相似文献   
407.
Cellular immune response is a major barrier to xenotransplantation. Human tumor necrosis factor-α (hTNF-α) possesses cross-species activity and directly amplifies the immune rejection via the upregulation of adhesion molecules on porcine endothelium. We investigated the role of protein tyrosine phosphorylation in the induction of expression of E-sclectin and vascular cell adhesion molecule-1 (VCAM-1), and the augmentation of adhesion of human peripheral blood monocytes (PBMo) and natural killer cells (PBNK), after rhTNF-α-stimulation of porcine aortic endothelial cells (PAEC) in vitro, rhTNF-α-increased adhesiveness of PAEC for both PBMo and PBNK was dose-dependently reduced by pretreatment of PAEC with the selective protein tyrosine kinase (PTK) inhibitor genistein. The inhibitory effect occurred at the early time of PAEC activation triggered by rhTNF-α, and was completely reversible. PTK activity assay indicated that genistein also suppressed rhTNF-α stimulated activation of protein tyrosine kinases (PTKs) in PAEC in a dose-dependent manner. Flow cytometric analysis showed that genistein inhibited the upregulation of E-selectin and VCAM-1 by rhTNF-α. These results suggest that PTKs may regulate the expression of E-selectin and VCAM-1 on PAEC and the adherence of PBMo and PBNK induced by rhTNF-α. Moreover, dietary genistein, used as an adhesion antagonist, may contribute to managing the cell-mediated rejection in the clinical application.  相似文献   
408.
A dense Ba0.5Sr0.5Co0.8Fe0.2O3-δ membrane tube was prepared by the extruding method. Furthermore, a membrane reactor with this tubular membrane was successfully applied to partial oxidation of methane (POM) reaction, in which the separation of oxygen from air and the partial oxidation of methane are integrated in one process. At 875℃, 94% of methane conversion, 98% of CO selectivity, 95% of H2 selectivity, and as high as 8.8 mL/(min · cm2) of oxygen flux were obtained. In POM reaction condition, the membrane tube shows a very good stability.  相似文献   
409.
嗅神经鞘细胞移植恢复大鼠损伤脊髓的功能   总被引:1,自引:0,他引:1  
为探讨嗅神经鞘细胞移植恢复大鼠损伤脊髓的功能 ,将成年大鼠分为脊髓半切洞损伤组 (A组 )和脊髓半切洞损伤 嗅神经鞘细胞移植组 (B)组 ,手术后应用联合行为评分 (CBS)感觉诱发电位 (SEP)和运动诱发电位 (MEP)检查 ,测定脊髓功能恢复情况 .结果 2组CBS得分 ,A组 >B组 ,SEP和MEP潜峰时均A组 >B组 ,统计学分析均有显著性差异 (P <0 0 5 ) .表明移植嗅神经鞘细胞能恢复损伤脊髓的功能  相似文献   
410.
The medical use of bee venom for rheumatoid arthritis (RA) has a very long tradition. In this study, isolation and purification of polypeptides from bee venom were carried out on sephadex chromatography, heparin sepharose CL-6B chromatography and HPLC. Several fractions were extracted, and their effects on activation of splenocyte and THP-1 cell were studied. The inhibitory fraction was selected for further studies. Finally, BVⅠ-2H that the HPLC elution profiles was a single peak was isolated by C8 column. ESI- MS detection results showed that BVⅠ-2H was a fraction of bee venom, and the molecular weight of the major component was 644.8. BVⅠ-2H could inhibit ConA-induced splenocyte proliferation, IL-1 production and interfere with splenocyte cycle in mice. Moreover, BVⅠ-2H could inhibit PMA-induced TNFa production in THP-1 cells, which was due to its inhibitory effects on TNFa mRNA expression and protein phosphorylation of IkBa. Our studies indicated that BVⅠ-2H was one of the anti-inflammatory components of bee venom.  相似文献   
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