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631.
总结了电力行业和炼化企业孤网稳控技术的研究应用现状,分析了炼化企业孤网后的过渡过程,提出了炼化企业孤网稳定控制的关键是频率稳定。根据炼化企业电力系统特点,对影响系统稳定的关键因素,即受控电力负荷和供热机组探讨了建模方法,提出了适用于炼化企业孤网的稳控策略。 相似文献
632.
为了解近年来太子河流域附石藻群落结构和水环境状况的变化趋势及二者的响应关系,于2009年和2014年对太子河全流域的附石藻群落和水环境因子进行调查分析,并探究了基于附石藻群落保护的主要水环境因子浓度限值.结果表明:①与2009年相比,2014年太子河流域的附石藻密度、物种丰富度、群落多样性均显著升高(P < 0.05);群落组成中对不良环境干扰呈负响应的藻属相对多度普遍升高,对不良环境干扰呈正响应的藻属相对多度普遍降低.②与2009年相比,2014年水环境因子中ρ(TDS)(TDS为总溶解性固体)、ρ(SS)、ρ(TN)、和ρ(NO3--N)显著降低(P < 0.05),ρ(DO)显著升高(P < 0.05).典范对应分析(canonical correspondence analysis,CCA)显示,2009年ρ(TN)和ρ(NH4+-N)是影响太子河流域附石藻群落的重要水环境因子;2014年ρ(TN)、ρ(NH4+-N)和ρ(TDS)对附石藻群落结构有重要影响.③经局部加权回归散点修匀法(locally weighted scatterplot smoothing,LOWESS)和独立样本t检验得出,当ρ(TDS)、ρ(TN)和ρ(NH4+-N)分别为185.00、1.00和0.22 mg/L时,其与P-IBI构成的拟合曲线存在拐点,且拐点两侧的P-IBI差异性显著(P < 0.05).研究显示,2009—2014年太子河流域的附石藻群落和水环境状况整体有所改善,合理控制ρ(TN)、ρ(NH4+-N)和ρ(TDS)对该流域的附石藻群落保护有重要意义. 相似文献
633.
论文基于江苏老濉河流域降水、水位和流量观测数据,利用统计-FloodArea模型相结合的方法计算了平原水网区致灾临界雨量。从水位变幅角度构建了流域不同时段累计面雨量-洪水涨幅统计模型,并计算出致灾临界雨量。在修订河道高程的基础上,利用FloodArea模型模拟典型暴雨洪涝事件的动态淹没过程,建立不同时段累计面雨量与模拟水位涨幅之间的幂函数关系,计算出另一组致灾临界雨量。对比发现两组致灾临界雨量基本一致,24 h三个等级致灾临界雨量对应泗洪气象站167 a、17 a和2 a一遇降水量。统计模型能较好地捕捉短时降水与洪水涨幅的关系,FloodArea模型则更好地反映了长历时暴雨洪涝事件的雨洪关系,整合两种方法,可得到更科学的平原水网区暴雨洪涝致灾临界雨量。 相似文献
634.
光是藻类进行光合作用的重要能量来源,决定藻类的初始生产力,当多种浮游藻类共同生存时,会一起竞争光强.光竞争能力强的浮游藻类浓度增加,光竞争能力较弱的则减少,从而完成水体中浮游藻类优势藻的替代.本文通过在以往建立的单藻模型的基础上,耦合入竞争模型,构建两种(多种)浮游藻类光竞争模型,尝试通过数值模拟,研究不同水体紊动中竞争藻属分别取得竞争优势的机理.模拟结果表明:稳态水体中,竞争藻属的自身垂向迁移决定藻浓度的垂向分布,具有浮力调节能力的微囊藻属占据上层水体优势地位,并取得竞争优势;动态水体中,竞争藻属垂向分布均较为均匀,生长速率决定藻的竞争优势,小球藻属生长速率快,最终易取得竞争优势.此外,考虑浮游藻属的动态自遮蔽,会加速稳态水体中微囊藻属取得竞争优势,并限制动态水体中小球藻属的无限制生长,使得模拟结果更加符合实际情况. 相似文献
635.
通过毒理学“大数据”,挖掘三丁基锡(TBT)潜在的生物影响信息,预测分析TBT暴露与人类相关疾病的关系.通过比较毒理组学数据库(CTD)搜集到488个和TBT具有相互作用的基因.基因相互作用网络图显示TP53拥有相关联基因最多,处于中心地位;其次是ESR1和FN1.CTD分析与TBT相关的疾病,发现前10类疾病分别是癌症、神经系统疾病、心血管疾病、泌尿生殖系统疾病(女)、消化系统疾病、代谢疾病、泌尿生殖系统疾病(男)、内分泌系统疾病、免疫系统疾病、呼吸道疾病.KEGG通路和DAVID基因功能注释分析,发现TBT不仅和代谢性疾病有较高的关联性,其相互作用基因在糖代谢途径上亦有较密集的基因功能注释.PASS的活性预测也发现TBT可能影响多种与糖代谢相关的酶生物活性.这提示TBT对糖代谢相关疾病的影响应引起人们的注意. 相似文献
636.
Tetrabromobisphenol A (TBBPA) and its derivatives are now being highly concerned due to their emerging environmental occurrence and deleterious effects on non-target organisms. Considering the potential neurotoxicity of TBBPA derivatives which has been demonstrated in vitro, what could happen in vivo is worthy of being studied. Tetrabromobisphenol A bis(2-hydroxyethyl ether) (TBBPA-BHEE), a representative TBBPA derivative, was selected for a 21-day exposure experiment on neonatal Sprague Dawley (SD) rats through intranasal administration. The neurobehavioral, histopathological changes, and differentially expressed genes based on RNA microarray were investigated to evaluate the neurological effects of this chemical. The results indicated that TBBPA-BHEE exposure significantly compromised the motor co-ordination performance and the locomotor activities (p < 0.05). The neurobehavioral phenotype could be attributed to the obvious histopathological changes in both cerebrum and cerebellum, such as neural cell swelling, microglial activation and proliferation. A total of 911 genes were up-regulated, whereas 433 genes were down-regulated. Gene set enrichment analysis showed multiple signaling pathways, including ubiquitin-mediated proteolysis and wingless-int (Wnt) signaling pathway etc. were involved due to TBBPA-BHEE exposure. The gene ontology enrichment analysis showed the basic cellular function and the neurological processes like synaptic transmission were influenced. The toxicological effects of TBBPA-BHEE observed in this study suggested the potential neuronal threaten from unintended exposure, which would be of great value in the biosafety evaluation of TBBPA derivatives. 相似文献
637.
The discharge of heavy metal ions such as Cu~2+and Pb~2+poses a severe threat to public health and the environment owing to their extreme toxicity and bioaccumulation through food chains Herein, we report a novel organic–inorganic hybrid adsorbent, Al(OH)_3-poly(acrylamide dimethyldiallylammonium chloride)-graft-dithiocarbamate(APD), for rapid and effectiv removal of Cu~2+and Pb~2+. In this adsorbent, the "star-like" structure of Al(OH)3 poly(acrylamide-dimethyldiallylammonium chloride) served as the support of dithiocarbamat(DTC) functional groups for easy access of heavy metal ions and assisted development of larg and compact floccules. The synthesized adsorbent was characterized by scanning electron microscopy(SEM), transmission electron microscopy(TEM), Fourier transform infrared spectroscopy(FTIR), and thermogravimetric analysis(TGA). APD was demonstrated to hav rapid adsorption kinetics with an initial rate of 267.379 and 2569.373 mg/(g·min) as well a superior adsorption capacities of 317.777 and 586.699 mg/g for Cu~2+and Pb~2+respectively. Th adsorption process was spontaneous and endothermic, involving intraparticle diffusion and chemical interaction between heavy metal ions and the functional groups of APD. To assess it versatility and wide applicability, APD was also used in turbid heavy metal wastewater, and performed well in removing suspended particles and heavy metal ions simultaneously through flocculation and chelation. The rapid, convenient and effective adsorption of Cu~2+and Pb~2+give APD great potential for heavy metal decontamination in industrial applications. 相似文献
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640.
Combined toxicity of herbicides to non-target crops is usually resulted from their successive application. The present study was conducted to assess the combined toxicity of flufenacet (FLU) and imazaquin (IMA) to sorghum with their concentration in soil pore water. The concentrations that inhibited growth by 50% (IC50) of FLU and IMA individually and their combination estimated from the herbicide concentrations in soil pore water notably differed from those based on the amended concentrations, due to the decline in bioavailability resulting from adsorption of the herbicides onto soil. According to the amended concentrations, the combined effect of FLU and IMA in soil on sorghum growth was identified as additive action. Based on the concentration in soil pore water, however, it was determined to be antagonism, which was identical to that observed in a test using culture solution. The results revealed that pore water herbicide concentration might be an effective tool to assess the combined toxicity of herbicides in soil to rotational crops. 相似文献