烟气脱硝对锅炉运行的影响

对火电厂燃煤机组采用烟气脱硝装置后将对锅炉运行产生的诸多影响进行分析,提出保证锅炉安全运行所的防范措施。     

基于球向量机的图像分割

由于图像数据量庞大,将标准支持向量机应用于图像分割时,其训练的时间复杂度较高。通过使用球向量机对图像进行分割,以降低训练过程消耗的时间。实验表明,在无噪声和有噪声情况下,使用球向量机对图像进行分割,其分割效果和抗噪性能与标准支持向量机的分割效果基本相同。然而,球向量机在训练过程中所消耗的时间显著小于标准支持向量机。应用球向量机进行图像分割,可以显著提高图像分割的整体性能。     

沉积速率及相关工艺条件对直流反应磁控溅射制备TiO2薄膜性质的影响

在玻璃基板上用直流反应磁控溅射钛靶的方法制备TiO2 薄膜。在溅射总气压为 0 4Pa ,氧氩比分别为 1∶9,1∶5及 1∶3 2的情况下 ,调节溅射功率使沉积速率由 0 99nm/min变化到 12 12nm/min ,而且当基板温度为 34 0℃时 ,薄膜在可见光范围内的平均折射率基本不变 ,为 2 48± 0 0 3,而薄膜的表面形貌却有明显变化。XRD表明 ,在pO2 /pAr为 1∶9的条件下 ,薄膜中出现了TiOx(x <2 )的晶粒 ,但这对薄膜的光学性质并无影响。另外对TiO2 薄膜用于多层光学薄膜也作了初步试验及讨论     

某高原城市的供水方案研究

根据高原城市的气候、地理特点,从供水规模、水源选择、开采方式、工艺流程、设备选择等方面论述了城市供水方案.针对供水工程中存在的地理位置特殊、城市规划不明、地表水取用困难、供水区地形起伏大、建设用地紧张、常规材料设备使用受限等问题,结合区域实际进行了分析研究,并提出了相应的解决措施.     

Effect of food azo dye tartrazine on learning and memory functions in mice and rats, and the possible mechanisms involved

Tartrazine is an artificial azo dye commonly used in human food and pharmaceutical products. The present study was conducted to evaluate the toxic effect of tartrazine on the learning and memory functions in mice and rats. Animals were administered different doses of tartrazine for a period of 30 d and were evaluated by open-field test, step-through test, and Morris water maze test, respectively. Furthermore, the biomarkers of the oxidative stress and pathohistology were also measured to explore the possible mechanisms involved. The results indicated that tartrazine extract significantly enhanced active behavioral response to the open field, increased the escape latency in Morris water maze test and decreased the retention latency in step-through tests. The decline in the activities of catalase, glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) as well as a rise in the level of malonaldehyde (MDA) were observed in the brain of tartrazine-treated rats, and these changes were associated with the brain from oxidative damage. The dose levels of tartrazine in the present study produced a few adverse effects in learning and memory functions in animals. The mechanisms might be attributed to promoting lipid peroxidation products and reactive oxygen species, inhibiting endogenous antioxidant defense enzymes and the brain tissue damage. PRACTICAL APPLICATION: Tartrazine is an artificial azo dye commonly used in human food and pharmaceutical products. Since the last assessment carried out by the Joint FAO/WHO Expert Committee on Food Additives in 1964, many new studies have been conducted. However, there is a little information about the effects on learning and memory performance. The present study was conducted to evaluate the toxic effect of tartrazine on the learning and memory functions in animals and its possible mechanism involved. Based on our results, we believe that more extensive assessment of food additives in current use is warranted.     

High-Throughput Screening of Heterogeneous Transition Metal Dual-Atom Catalysts by Synergistic Effect for Nitrate Reduction to Ammonia

Nitrate reduction to ammonia has attracted much attention for nitrate (NO₃^-) removal and ammonia (NH₃) production. Identifying promising catalyst for active nitrate electroreduction reaction (NO₃RR) is critical to realize efficient upscaling synthesis of NH₃ under low-temperature condition. For this purpose, by means of spin-polarized first-principles calculations, the NO₃RR performance on a series of graphitic carbon nitride (g-CN) supported double-atom catalysts (denoted as M₁M₂@g-CN) are systematically investigated. The synergistic effect of heterogeneous dual-metal sites can bring out tunable activity and selectivity for NO₃RR. Amongst 21 candidates examined, FeMo@g-CN and CrMo@g-CN possess a high performance with low limiting potentials of -0.34 and -0.39 V, respectively. The activities can be attributed to a synergistic effect of the M₁M₂ dimer d orbitals coupling with the anti-bonding orbital of NO₃^-. The dissociation of deposited FeMo and CrMo dimers into two separated monomers is proved to be difficult, ensuring the kinetic stability of M₁M₂@g-CN. Furthermore, the dual-metal decorated on g-CN significantly reduces the bandgap of g-CN and broadens the adsorption window of visible light, implying its great promise for photocatalysis. This work opens a new avenue for future theoretical and experimental design related to NO₃RR photo-/electrocatalysts.