Effects of La3+, Ce3+ on nitrogen removal in sequencing batch reactor

Batch experiments were conducted to study the short-term biological effects of rare earth ions (La³⁺, Ce³⁺) and their mixture on the nitrogen removal in a sequencing batch reactor (SBR). The data showed that higher NH₄ ⁺-N removal rate, total inorganic nitrogen removal efficiency, and denitrification efficiency were achieved at lower concentrations of rare earth elements (REEs) (<1 mg/L). In the first hour of the aeration stage of SBR, the presence of REEs increased the total inorganic nitrogen removal efficiency and NH₄ ⁺-N removal efficiency by 15.7% and 10%–15%, respectively. When the concentrations of REEs were higher than 1 mg/L, the total inorganic nitrogen removal efficiency decreased, and nitrate was found to accumulate in the effluent. When the concentrations of REEs was up to 50.0 mg/L, the total inorganic nitrogen removal efficiency was less than 30% of the control efficiency with a high level of nitrate. Lower concentrations of REEs were found to accelerate the nitrogen conversion and removal in SBR.     

湿法脱硫系统设计无旁路相关问题的探讨

介绍国内电厂首次投运的无旁路脱硫系统,其具有无GGH、引风机和增压风机合并、"烟塔合一"的特点。通过与其他脱硫系统的比较,讨论了无旁路脱硫系统吸收塔、烟道、公用系统以及除尘器的设计和选型特点,总结了其易出现的问题及运行中的控制方法。根据调试经验,给出了无脱硫旁路系统的运行步序原则。     

西安市灰霾天气时间和区域分布特征及影响因素

依据1961—2005年共45年,西安、户县、长安、蓝田、临潼、高陵和周至7个气象台站灰霾观测资料,分析了灰霾天气时间和区域分布特征,并根据1996—2005年近10年西安逐月平均灰霾日数与近10年逐月主要气象要素相关性分析,得出:西安市20世纪70年代是灰霾日出现的高峰时期,并呈逐年减少趋势,灰霾发生的中心区域也在向郊区东南部转移;从影响灰霾天气形成的气象条件来看,气温越低,降水量和风速越小,日照越少,气压越高,越有利于灰霾天气的形成。     

川藏公路滑坡加固预应力锚索受力分析研究

以川藏公路102滑坡群滑坡处理为依托,仔细研究了滑坡体的工程地质特征。对由大型松散堆积物形成的2#滑坡锚索加固工程稳定性进行了研究,由于在2#滑坡中,滑动面和预应力锚索之间的夹角很大,作用在锚索上面的力还包括轴向拉力和侧向的弯矩和剪力。通过对力的分析和计算证明,使用梁单元来进行计算更加符合实际使用要求,因此,预应力锚索的应用不仅能够合理地改善结构的受力条件,并且能够充分地利用材料本身的强度特性,节约了工程的使用费用,具有很好的推广应用价值。     

Trace analysis of airborne toluene diisocyanate as a pentafluorobenzyl derivative by gas chromatography with electron capture detection

Trace analysis of airborne toluene diisocyanate (TDI) vapor was accomplished by measuring the derivative using gas chromatography with electron‐capture detector after collecting gas samples with a microimpinger containing 2 ml toluene, 1 μl pentafluorobenzyl alcohol, and 1 μl triethylamine. The sampling efficiency was determined to be 99.4% for short‐term exposure level of TDI and the 2,4‐ and 2,6‐isomers of TDI were well separated. The derivative was identified to be a new compound with a molecular weight of 570 by mass spectrometry in fast atomic bombardment mode and nuclear magnetic resonance spectrometry. This method is convenient and can be applied in the field where airborne TDI is in vapor form.     

Water use efficiency of a mixed cropping system of corn with grasses

A new cropping system of corn mixed with grasses was tried to make full and efficient use of water and to ease environmental problems such as soil erosion by water and wind in grain and forage feed production practices. Field experiments were conducted to investigate the water use efficiency under this mixture cropping system. Six treatments with two replicates were arranged as: bare field, corn only, rye only, alfalfa only, rye–corn mixture and alfalfa–corn mixture. Lysimeters were used to measure different components of water consumption in the crop fields for water use efficiency estimation. From the yields and water consumption of crops under different treatments, combined water use efficiency of corn and grasses were estimated. The results showed that WUEs in the mixed cropping fields of corn–grasses were much higher than those in the fields where only corn or grass were grown. Averaged WUE was 3.71 kg/m³ from the corn and rye mixture fields, 30% higher than that from the plots where only corn or rye were grown. Averaged WUE was 4.55 kg/m³ from the alfalfa and corn mixture fields, 60% higher than that from the fields where only corn or alfalfa were grown. Under the same conditions of irrigation, yields from the rye and corn mixture plots increased by 33%, as compared with those from fields where only corn or rye were grown. The yields from alfalfa and corn mixture fields were 61% higher than those from fields where only corn or alfalfa were grown. The experimental results also indicated that corn and alfalfa mixture cropping is better than a corn–rye mixture system.     

苯和甲醛联合染毒对小鼠脾脏的损伤

为了探讨苯和甲醛联合染毒对小鼠脾脏的损伤以及二者是否具有一定的协同作用,选择BALB/c雄性小鼠30只,随机分为5组,每组6只,设苯组、甲醛组、苯和甲醛联合染毒组及玉米油对照组和空白对照组,对小鼠进行气态甲醛吸入染毒或/和苯玉米油溶液灌胃染毒。染毒结束后对小鼠脾脏进行组织病理学观察,并且测定脾脏的脏器系数以及脾脏组织的活性氧(ROS)和丙二醛(MDA)的含量。结果显示,苯和甲醛联合染毒组小鼠脾脏组织中ROS的含量与空白对照组相比有极显著的上升趋势(P<0.01),脾脏的脏器系数以及脾脏组织中MDA的含量与空白对照组相比有显著性差异(P<0.05)。此外,在脾脏免疫组织形态变化以及脾脏组织中MDA含量这2个生理生化指标上,苯和甲醛联合染毒对小鼠脾脏的损伤具有一定的协同作用。     

基于风险分析的城市防灾减灾规划编制——以地震规划为例

为减轻城市灾害损失,提出城市防灾减灾规划编制方法,将减灾规划分为准备、风险分析、编制和实施4个步骤。依据风险分析结果,制订防灾减灾规划目标、减灾措施及策略。给出典型的地震灾害风险分析方法。以某市为例,算出其各区域的地震风险。根据风险等级划分标准确定各区域的地震风险可接受水平。基于此结果在GIS平台上的表达,可知市内旧城区的地震风险很高,须立刻采取风险减缓措施。对减灾措施进行优化,结果表明:加快现有设防不足工程的抗震加固,严抓新建工程的抗震设防水准是提高该市抗震减震能力的关键。     

焊接防护具抗热穿透性能测试仪的研制

焊接防护具是指一种保护佩戴者免受由焊接或相关作业所产生的有害光辐射及其他特定有害因素的装置。它是从事焊接与热切割作业人员必备的个体防护装备。抗热穿透性能是表征焊接防护具产品质量和安全性能的最重要技术指标之一。然而,如何快速、便捷、节能、准确地对焊接防护具抗热穿透性能进行检测,是迫切需要解决的技术难题。本文在简要分析国内外眼面部防护标准中抗热穿透性能技术要求和测试方法的基础上,提出了一种测试焊接防护具抗热穿透性能的方法,并成功研制了焊接防护具抗热穿透性能测试仪。     

我国地面沉降灾害现状与防灾减灾对策

介绍了中国大陆地区地面沉降现状,分析了地面沉降的危害,提出要通过加强组织管理和协调,统筹地表水和地下水,建立监测预警体系,合理编制城市规划来预防和减轻地面沉降灾害。