活性污泥生长的控制

在污水处理过程中，针对不同的运行环境，我们选择适当的运行工艺和参数。通过控制菌胶团细菌和丝状菌平衡生长，或者是使固着型原生动物占优势，来获得良好的活性污泥，保证出水达标排放。     

连续微滤系统膜垢生长过程的模型与模拟

应用分形理论中DLA模型,建立了膜垢分形生长模型。通过改变边界条件和随机粒子产生的几率,得到不同条件下膜垢形成与生长过程的模拟图像;采用显微粒子图像技术,通过量子点荧光示踪剂对不同条件下连续微滤系统膜垢的形态和流场进行同时观测与分析。结果表明,模拟与实验所获得的分形维数相近,该模型能够较好地模拟膜垢形成与生长过程;运用该模型数值模拟分析了流场和悬浮物浓度对膜垢生长过程的影响及其动态变化规律。     

链霉菌WH63的抑藻效应

研究链霉菌WH63抑藻效应。以铜绿微囊藻作为受试对象,通过平板实验、液体发酵、链霉菌WH63发酵产物分析、藻毒素含量测定和水培青菜,探讨链霉菌WH63抑藻效应。结果发现,链霉菌WH63活菌和过滤除菌后的发酵液均有抑制铜绿微囊藻生长的能力,第4天时接种3%过滤除菌的链霉菌WH63发酵液抑藻率就达到了96.7%,且WH63菌株的发酵液具有很好的热稳定性,乙酸乙酯的萃取WH63菌株发酵液抑藻效果最好,其抑藻物质为脂溶性弱极性物质。进一步分析其第15天的抑藻水样,COD含量比正常生长的铜绿微囊藻下降了61.4%,BOD下降了13.4%,藻毒素含量比其低57.9%,继续培养到第40天时都没有回绿现象,且水样清澈。用杀藻后的水样直接浇灌青菜种子,观察种子萌发数,结果表明,处理后的水样发芽率为100%,发芽势、活力指数、茎长和幼苗鲜重比水对照分别提高10.2%、147%、121%和71.6%。实验表明,用链霉菌WH63抑藻后的水样具有很好的促植物生长和提高植物抗性的效果,为链霉菌以后运用到水培蔬菜抑藻剂的开发提供了一定的理论基础。     

丝状菌污泥膨胀及其致密过程中菌丝体演替规律

为了探索丝状菌的致密途径、解决丝状菌污泥膨胀的难题,从丝状菌的自身特点及外部条件出发研究了其在污泥膨胀及致密过程中菌丝体的演替规律。研究发现,致密生长的大絮体对丝状菌的种类是有选择性的,那些丝体较弯曲、丝体强度较大、贮存能力强的菌丝体更利于形成聚集态生长。另外,研究表明,不同种类丝状菌的生长势和存贮能力不同,对底物的利用上亦存在着竞争关系。实验中存在的几个菌种对PHB颗粒的存贮能力由高到低依次为:Nostocoida limicola Ⅱ、Type 1851、Type 0701、Type 021N型菌体。     

Se(Ⅳ)和Se(Ⅵ)对小白菜生长及生理效应的影响

用盆栽试验研究了不同含量Se(Ⅳ)和Se(Ⅵ)对小白菜生长和生理效应的影响.结果表明,不同含量Se(Ⅳ)和Se(Ⅵ)对小白菜体生长和生理代谢的影响不尽相同.低含量硒（Se(Ⅳ)<10.0 mg·kg-1、Se(Ⅵ)<5.0 mg·kg-1）能够促进小白菜的生长,使其根变粗, 诱导脯氨酸的产生,阻止丙二醛（MDA）的合成,增强白菜的抗逆性,使其生物量明显提高;高含量硒会抑制小白菜的生长,导致植物体内脯氨酸合成下降,MDA含量增加,叶及根系生长受到抑制,地上和地下部干重显著急速下降（p<0.01）.小白菜根长、叶面积等生长指标均随Se(Ⅳ)和Se(Ⅵ)含量的增大而显著下降（p<0.01）;抑制小白菜根系生长的Se(Ⅳ)含量为60 mg·kg-1,明显高于Se(Ⅵ)含量（20.0 mg·kg-1）.相同硒含量下,Se(Ⅳ)处理的小白菜地上部干重为Se(Ⅵ)的1.1~3.0倍,说明本试验条件下Se(Ⅵ)的生物有效性和毒性均大于Se(Ⅳ).Se(Ⅵ)处理小白菜地上部分的硒含量显著高于地下部分,而Se(Ⅳ)处理小白菜地下部分的硒含量显著高于地上部分,小白菜地上和地下部分对Se(Ⅵ)的吸收量均显著高于Se(Ⅳ).综合生长和生理因子分析表明,地上部分生物量是反映Se(Ⅳ)及Se(Ⅵ)处理土壤上小白菜生长状况的理想指标.     

伺服系统加速可靠性增长试验应用与探讨

加速可靠性增长试验是可靠性试验新的研究方向和应用领域,对于可靠性要求高、任务时间长、产品子样少或价格昂贵的航天产品的可靠性增长和评价工作有良好的实施效果.对加速可靠性增长试验技术的基本原理、应用和实施的必要性、加速应力选取方法和注意事项进行了阐述,结合某型伺服系统加速可靠性增长试验方案设计实例,对传统可靠性增长试验方案...     

Effects of seed aerosols on the growth of secondary organic aerosols from the photooxidation of toluene

Hydroxyl radical （.OH）-initiated photooxidation reaction of toluene was carried out in a self-made smog chamber. Four individual seed aerosols such as ammonium sulfate, ammonium nitrate, sodium silicate and calcium chloride, were introduced into the chamber to assess their influence on the growth of secondary organic aerosols （SOA）. It was found that the low concentration of seed aerosols might lead to high concentration of SOA particles. Seed aerosols would promote rates of SOA formation at the start of the reaction and inhibit its formation rate with prolonging the reaction time. In the case of ca. 9000 pt/cm^3 seed aerosol load, the addition of sodium silicate induced a same effect on the SOA formation as ammonium nitrate. The influence of the four individual seed aerosols on the generation of SOA decreased in the order of calcium chloride〉sodium silicate and ammonium nitrate〉ammonium sulfate.     

Low-carbon transition of iron and steel industry in China: Carbon intensity, economic growth and policy intervention

As the biggest iron and steel producer in the world and one of the highest CO₂ emission sectors, China's iron and steel industry is undergoing a low-carbon transition accompanied by remarkable technological progress and investment adjustment, in response to the macroeconomic climate and policy intervention. Many drivers of the CO₂ emissions of the iron and steel industry have been explored, but the relationships between CO₂ abatement, investment and technological expenditure, and their connections with the economic growth and governmental policies in China, have not been conjointly and empirically examined. We proposed a concise conceptual model and an econometric model to investigate this crucial question. The results of regression, Granger causality test and impulse response analysis indicated that technological expenditure can significantly reduce CO₂ emissions, and that investment expansion showed a negative impact on CO₂ emission reduction. It was also argued with empirical evidence that a good economic situation favored CO₂ abatement in China's iron and steel industry, while achieving CO₂ emission reduction in this industrial sector did not necessarily threaten economic growth. This shed light on the dispute over balancing emission cutting and economic growth. Regarding the policy aspects, the year 2000 was found to be an important turning point for policy evolution and the development of the iron and steel industry in China. The subsequent command and control policies had a significant, positive effect on CO₂ abatement.     

嘉陵江重庆磁器口段藻类生长模拟研究

藻类生长有一个适合的流速,即临界流速,在其他条件相同的情况下,处于临界流速状态的藻类生长更快.在藻类生长模型中,引人流速影响函数,数值模拟嘉陵江重庆城区磁器口河段2007年2月-7月的藻类生长情况,模拟结果与实测结果吻合较好.研究结果表明.流速在0.03-0.05 m/s比较适合研究河段的藻类生长.     

颤蚓在活性污泥中的生长研究

以颤蚓为研究对象,活性污泥为底物,通过批量培养实验,考察了颤蚓在20℃和25℃2个不同温度下的生长状况.在16周的培养过程中,颤蚓在活性污泥中的生长较好地符合Logistic曲线;25℃更适于颤蚓生长,颤蚓个体在25℃下体重和体长的增长速率分别是0.0470mg·(条·d)-1和0.1936mm·(条·d)-1.同时,颤蚓在25℃下的体重-体长关系式为W=0.008 L2.028 (R2=0.8685),符合颤蚓科蠕虫体重-体长关系式的一般规律.与其它底物相比,以活性污泥为底物时的颤蚓生长并未表现出明显差别.