A study on the reaction characteristics of vanadium-impregnated natural manganese oxide in ammonia selective catalytic reduction

This study investigated the effect of adding vanadium (V) to natural manganese oxide (NMO) in ammonia (NH3) selective catalytic reduction (SCR). The addition of V to NMO decreased the catalytic activity at low temperatures by blocking the active site. However, the enhancement of catalytic activity was achieved by controlling NH3 oxidation at high temperatures. From the NH3 temperature programmed desorption and oxygen on/off test, it was confirmed that the amount of Lewis acid site and active lattice oxygen of the catalyst affects the catalytic performance at low temperature.     

恶臭假单胞菌降解苯酚的动力学研究

研究了恶臭假单胞菌（Pseudomonas putida LY1）利用苯酚作为唯一碳源和能源时的生长动力学特性。通过对该菌株在不同温度、pH和初始苯酚浓度下的生长和降解情况的研究,可知该菌株在温度为25℃左右、pH为中性和偏碱性的条件下具有更高的降解活性。细菌的生长动力学过程符合基质抑制型的Haldane方程,可利用该...     

太阳翼驱动机构的扰振力矩测试与分析

为了研究太阳翼驱动机构(solar array drive assembly,SADA)驱动太阳翼运行期间所产生的扰振力矩特性,设计了一套地面测试系统,包括应变式微振动测试平台、柔性负载以及模拟SADA在轨无重力工作环境的重力卸载装置。阐述了所设计测试系统的工作原理,并利用该测试系统进行了试验测试。测试结果表明:SADA驱动柔性负载运行期间所产生扰振力矩的扰振频率成分主要包含两部分,即:1)SADA驱动柔性负载耦合系统的低阶扭转固有频率;2)SADA电脉冲信号的输入频率及其高阶谐波。     

Effects of taxonomy,sediment, and water column on C:N:P stoichiometry of submerged macrophytes in Yangtze floodplain shallow lakes,China

Carbon (C), nitrogen (N) and phosphorus (P) are the three most important essential elements limiting growth of primary producers. Submerged macrophytes generally absorb nutrients from sediments by root uptake. However, the C:N:P stoichiometric signatures of plant tissue are affected by many additional factors such as taxonomy, nutrient availability, and light availability. We first revealed the relative importance of taxonomy, sediment, and water column on plant C:N:P stoichiometry using variance partitioning based on partial redundancy analyses. Results showed that taxonomy was the most important factor in determining C:N:P stoichiometry, then the water column and finally the sediment. In this study, a significant positive relationship was found between community C concentration and macrophyte community biomass, indicating that the local low C availability in macrophytes probably was the main reason why submerged macrophytes declined in Yangtze floodplain shallow lakes. Based on our study, it is suggested that submerged macrophytes in Yangtze floodplain shallow lakes are primarily limited by low light levels rather than nutrient availability.

     

改进的TLI指数法及其在巢湖营养状态评价中的应用

对巢湖2000—2008年的监测数据运用SPSS做统计分析,得出叶绿素a与总氮、总磷和透明度的相关系数。通过得出的权重结果,分析出与26个湖泊的差异性,构建了改进的综合营养状态指数(TLI)评价方法,并提出评价的4个步骤。以巢湖为例,运用该方法对湖泊的营养状态进行评价,且对巢湖的富营养化程度做了年际和年内变化的综合评价,评价结果显示各营养物指标的相关关系在近30年有了较大变化,巢湖的富营养化现象已日益严重,已从轻度富营养化状态转变为中度富营养化状态。     

广州某观测点春季大气样品中二NFDA1英日均浓度变化分析

在广州某商住区楼顶开展为期1个月的大气样品连续采样,利用高分辨气相色谱-高分辨质谱仪测定了样品中17种毒性二 NFDA1 英(PCDD/Fs)的含量。结果表明,该采样点位样品二 NFDA1 英I-TEQ浓度范围为0.094~1.34 pg I-TEQ/m³,样品日平均浓度相对偏差范围为3.2%~118.8%,6日平均浓度相对偏差范围为1.2%~60.1%,6日平均值更能较好地反映样品长期平均浓度。气象变化对样品中二 NFDA1 英I-TEQ浓度有明显影响,降雨后样品中的二 NFDA1 英I-TEQ浓度明显低于降雨前,降雨前或降雨中样品的二 NFDA1 英I-TEQ浓度与降雨后样品比值最高达到9.0,样品二 NFDA1 英I-TEQ浓度与PM_2.5的线性相关性高于其与TSP、温度相关性,上述三者的r值和P值分别为0.637、-0.296、0.271和0.611、0.326、0.329。     

Groundwater geochemistry diagnostics during in situ ERH remediation

In situ remediation represents a series of challenges in interpreting the monitoring data on remedial progress. Among these challenges are problems in determining the progress of the remediation and the mechanisms responsible, so that the process can be optimized. The release of organic pollutants to groundwater systems and in situ remediation technologies alter the groundwater chemistry, but outside of natural attenuation studies using inorganic chemical analyses as indicators of intrinsic biodegradation, typically little attention has been paid to the changes in inorganic groundwater chemistry. Smith (2008) noted that during an electrical resistance heating remediation that took place at a confidential site in Chicago, a two‐orders‐of‐magnitude increase in chloride concentrations occurred during the remediation. This increase in chloride resulted in a corresponding increase in calcium as a result of what is known as the common ion effect. Carbon dioxide is the gas found in highest concentrations in natural groundwater (Stumm & Morgan, 1981), and its fugacity (partial pressure) corresponds directly with calcium concentrations. Carbon dioxide at supersaturation in groundwater is capable of dissolving organic compounds, such as trichloroethene, facilitating removal of nonaqueous‐phase liquids at temperatures below the boiling point of water. One means of diagnosing these reactions is through the use of compound‐specific isotopic analysis, which is capable of distinguishing between evaporation, biodegradation, and differences in sources. The appropriate diagnosis has the potential to optimize the benefits from these reactions, lower energy costs for removal of nonaqueous‐phase liquids, and direct treatment where it is needed most. © 2010 Wiley Periodicals, Inc.     

Characterization of the extracellular biodemulsifiers secreted by Bacillus cereus LH-6 and the enhancement of demulsifying efficiency by optimizing the cultivation conditions

A highly efficient demulsifying strain, LH-6, was isolated from petroleum-contaminated soil and identified as Bacillus cereus by 16S rDNA gene analysis. It achieved 95.61 and 95.40 % demulsifying ratios within 12 h for water-in-oil (W/O) and oil-in-water (O/W) model emulsions, respectively. Fourier transform infrared spectroscopy (FT-IR) and thin-layer chromatography (TLC) detections indicated that the LH-6’s extracellular biodemulsifiers were different types of lipopeptides for the W/O and O/W emulsions. Optimization of the culture medium composition was conducted to improve the biosynthesis and demulsifying efficiency of the biodemulsifier. The optimal carbon source was liquid paraffin, while waste frying oil could also be an alternative carbon source. The optimal nitrogen sources were ammonium sulfate and yeast extract. To further enhance the biodemulsifier efficiency, the optimal cultivation conditions were determined using response surface methodology (RSM) based on central composite rotation design (CCRD). Using the optimized cultivation conditions, the demulsifying ratios increased to 98.23 and 97.65 % for the W/O and O/W model emulsions, respectively.     

恩施地区生态足迹和生态承载力评价

以恩施地区2010年统计数据为依据，对其2010年的生态足迹、生态承载力、生态盈余进行计算和分析，并将生态足迹、生态承载力、生态盈余和万元GDP生态足迹分别与恩施地区贫困村分布密度进行空间耦合。研究表明：（1）恩施地区人均生态盈余为0467 hm2，人均生态承载力为0947 1 hm2，人均生态足迹为048 hm2；（2）贫困村分布密度最高的来凤县、建始县人均生态盈余很少，而贫困村分布密度最低的利川市、咸丰县、宣恩县、鹤峰县，人均生态足迹最高和最低的县分别是咸丰县、宣恩县，鹤峰县的生态承载力最高，人均生态盈余最高的是宣恩县、鹤峰县，万元GDP生态足迹最高和最低的分别是利川市，巴东县；（3）通过生态足迹的研究，提出了恩施贫困地区需放大生态比较优势，〖JP2〗因地制宜，努力将生态盈余转化为直接的经济增长，使之能够有效的帮助贫困地区脱贫致富     

美军信息化单兵防护装备浅析

信息化单兵防护装备集战场防护、信息处理功能于一体,以士兵作战需求为核心,采用新材料及新技术,通过一体化、系统化集成设计,有效利用士兵身体作为携行平台,实现了单兵综合作战效能的提升。