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1.
对己二腈工业反应器提出了两釜串联带回流的模型,通过模拟计算得出模型的级间返混系数 f=6的结论。该模型能较好地预测工业反应器中物料组分浓度变化和气、液两相的流动特性;指出了现工业反应器的鼓泡中和段体积偏小是造成己二酸浓度偏高的关键;提出了可以通过增加串连一个鼓泡预反应段的改造方案,能有效地降低己二酸的浓度,从7%降至4%左右,从而能较好地减缓腐蚀和结焦。  相似文献   
2.
针对某区域用电负荷存在严重的季节性过载现象,以及可再生能源存在功率波动大、稳定性较差的问题,研制了多能(含水电、光伏、储能)、多端口的能量路由器装置及其能量管理系统.综合考虑当地多场景运行,解决了季节性过载问题,实现了能量的合理配置与利用.首先,对比分析选定能量路由器各端口变换器的拓扑结构;然后,对多场景下的工作模式进行介绍;最后,对含能量路由器的多能互补系统进行故障保护功能测试.测试结果表明,该系统具有较好的故障保护功能,有效实现了不同场景下的工作模式切换,直流母线电压稳定以及上层功率指令跟踪等功能,解决了当地用电负荷季节性过载和可再生能源功率波动较大的问题.  相似文献   
3.
Sixty sediment samples were collected from the main Songhua River in three years. Twelve polybrominated diphenyl ether ( PBDE) congeners ( BDE17, 28, 47, 66, 99, 100, 153, 154, 138, 183, and BDE?209) w...  相似文献   
4.
In infrastructure financed projects, in order to attract private investors, host governments often provide some guarantees. This paper develops a value model of minimum revenue guarantee with multiple-exercise real options under the impact of the emergency incident. The model is applied to infrastructure financed projects using the minimum revenue guarantee under simulation. The simulation results indicate that, before quantifying the value of the minimum revenue guarantee, it is necessary to forecast the jump degree and intensity of the emergency incident, as well as prevent and control risks arising from such emergencies. Otherwise, underestimation of the guarantee value will occur and the government will have to bear huge debt in this condition. We also analyze the dependence of the guaranteed value on the minimum guaranteed revenue level, initial revenue and number of exercise rights. For various conditions, the diagrams of the guaranteed value are also presented.  相似文献   
5.
柴红 《电信技术》2006,(12):39-41
首先着重分析了山西移动本地NGN的需求。阐述了山西移动NGN建设需要考虑的因素.最后就山西移动NGN的网络建设策略提出了具体的建议。  相似文献   
6.
本文介绍了珠钢续建工程炼钢系统中的不锈钢生产技术、废钢预热系统控制及工艺优化、续建电炉工艺设备操作参数优化、组织管理优化等先进技术,并从措施和步骤上探讨快速掌握、消化及管理引进的先进工艺技术。  相似文献   
7.
用电化学方法对负极添加剂进行了筛选,发现生物碱对铅电极有积极影响;电池试验表明,生物碱可提高负极活性物质利用率。  相似文献   
8.
Lung cancer is the leading cause of cancer death worldwide. miR-199a, which has two mature molecules: miR-199a-3p and miR-199a-5p, plays an important biological role in the genesis and development of tumors. We collected recent research results on lung cancer and miR-199a from Google Scholar and PubMed databases. The biological functions of miR-199a in lung cancer are reviewed in detail, and its potential roles in lung cancer diagnosis and treatment are discussed. With miR-199a as the core point and a divergence outward, the interplay between miR-199a and other ncRNAs is reviewed, and a regulatory network covering various cancers is depicted, which can help us to better understand the mechanism of cancer occurrence and provide a means for developing novel therapeutic strategies. In addition, the current methods of diagnosis and treatment of lung cancer are reviewed. Finally, a conclusion was drawn: miR-199a inhibits the development of lung cancer, especially by inhibiting the proliferation, infiltration, and migration of lung cancer cells, inhibiting tumor angiogenesis, increasing the apoptosis of lung cancer cells, and affecting the drug resistance of lung cancer cells. This review aims to provide new insights into lung cancer therapy and prevention.  相似文献   
9.
The barcode probe is a convenient and efficient tool for molecular cytogenetics. Tripidium arundinaceum, as a polyploid wild allied genus of Saccharum, is a useful genetic resource that confers biotic and abiotic stress resistance for sugarcane breeding. Unfortunately, the basic cytogenetic information is still unclear due to the complex genome. We constructed the Cot-20 library for screening moderately and highly repetitive sequences from T. arundinaceum, and the chromosomal distribution of these repetitive sequences was explored. We used the barcode of repetitive sequence probes to distinguish the ten chromosome types of T. arundinaceum by fluorescence in situ hybridization (FISH) with Ea-0907, Ea-0098, and 45S rDNA. Furthermore, the distinction among homology chromosomes based on repetitive sequences was constructed in T. arundinaceum by the repeated FISH using the barcode probes including Ea-0663, Ea-0267, EaCent, 5S rDNA, Ea-0265, Ea-0070, and 45S rDNA. We combined these probes to distinguish 37 different chromosome types, suggesting that the repetitive sequences may have different distributions on homologous chromosomes of T. arundinaceum. In summary, this method provide a basis for the development of similar applications for cytogenetic analysis in other species.  相似文献   
10.
Lignin, a by-product of pulping and biorefinery, has great potential to replace petrochemical resources for wastewater purification. However, the defects of lignin, such as severe heterogeneity, inferior reactivity and poor solubility, characterize the production process of lignin-based products by high energy consumption and serious pollution. In this study, several lignin fractions with relatively homogeneous structure were first obtained by organic solvent fractionation, and their structures were fully deciphered by various characterization techniques. Subsequently, each lignin component was custom-valued for wastewater purification based on their structural characteristics. Benefiting from the high reactivity and reaction accessibility, the lignin fraction (lignin-1) refined by dissolving in ethanol and n-butanol could been used as a raw material to produce cationic lignin-based flocculant (LBF) in a copolymerization system using green, cheap and recyclable ethanol as solvent. The lignin fraction (lignin-2) extracted by methanol and dioxane showed low reactivity and high carbon content, which was used to produce lignin-based activated carbon (LAC) with phosphoric acid as activator. Moreover, the influences of synthetic factors on the purification capacity were discussed, and the LBF and LAC produced under the optimal conditions showed distinguished purification effect on kaolin suspension and heavy metal wastewater, respectively. Furthermore, the corresponding purification mechanism and external factors were also elaborated. It is believed that this cleaner production strategy is helpful for the valorization of lignin in wastewater resources.  相似文献   
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