Changes in Rice Allelopathy and Rhizosphere Microflora by Inhibiting Rice Phenylalanine Ammonia-lyase Gene Expression

Gene expression of phenylalanine ammonia-lyase (PAL) in allelopathic rice PI312777 was inhibited by RNA interference (RNAi). Transgenic rice showed lower levels of PAL gene expression and PAL activity than wild type rice (WT). The concentrations of phenolic compounds were lower in the root tissues and root exudates of transgenic rice than in those of wild type plants. When barndyardgrass (BYG) was used as the receiver plant, the allelopathic potential of transgenic rice was reduced. The sizes of the bacterial and fungal populations in rice rhizospheric soil at the 3-, 5-, and 7-leaf stages were estimated by using quantitative PCR (qPCR), which showed a decrease in both populations at all stages of leaf development analyzed. However, PI312777 had a larger microbial population than transgenic rice. In addition, in T-RFLP studies, 14 different groups of bacteria were detected in WT and only 6 were detected in transgenic rice. This indicates that there was less rhizospheric bacterial diversity associated with transgenic rice than with WT. These findings collectively suggest that PAL functions as a positive regulator of rice allelopathic potential.     

Mineral behavior of low-temperature lignite ashes under gasification atmosphere

To investigate the mineral behavior of lignite ashes under gasification conditions, 450 °C Xiaolongtan lignite ash samples (XLT-LTA) treated at different temperatures or pressures under reducing atmosphere (H₂/CO₂=1: 1, volume ratio) have been examined by means of an SC-444 apparatus, a scanning electron microscope with an energy dispersive X-ray detector (SEM-EDX), and by X-ray diffraction (XRD). The results showed the sulfur content in the XLT-LTA to be much higher than that in ashes prepared at 815 °C, as a result of the release of sulfur dioxide during the oxidization of pyrite. With increasing temperature, the XLT-LTA particles gradually agglomerate and form partially molten surface entities with obvious apertures, and the content of iron and calcium in the congeries or molten parts increases due to the fusion of fine ash particles with the enrichment of iron and the formation of low-temperature eutectics of calcium and iron. An increase of pressure restrains the decomposition of calcite and muscovite, and promotes the formation of iron minerals (e.g., hercynite, cordierite, and sekaninaite) and orthoclase. The content of amorphous material also increases with increasing pressure.     

三聚氰胺装置解吸水解系统稳定运行的技改措施

简述了三聚氰胺装置解吸水解系统的工艺流程和工艺原理;分析了该系统试生产期间无法稳定运行的问题及原因;实施了解吸系统增加循环管线、水解器调整蒸汽管路等技改措施。结果表明,改造后的解吸水解系统运行稳定,工艺冷凝液处理量由30t/h提高到33t/h,实现了三聚氰胺装置工艺废水的零排放。     

铁钼法甲醛工艺中甲醇转化率低的原因及改进

介绍了河南开祥化工有限公司引进美国DBW铁钼氧化法生产甲醛的工艺,从空气质量、催化剂、氧含量、空速、反应温度、吸收水pH、甲醇雾化率等方面,分析了甲醛生产过程中甲醇转化率低的原因,并总结了实际生产中提高甲醇转化率的方法:控制工艺操作参数、保证催化剂装填质量、注意催化剂的保护等。     

利用微生物混合静止发酵降低赤霉素萃余液中COD含量

[目的]降低赤霉素萃余液中COD含量,减轻赤霉素萃余液对废水处理站运行负荷的压力。[方法]以赤霉素萃余液为基础培养基,适当添加糖蜜和KH2P O4后,混合接入耐盐耐酸的酵母菌与乳酸菌,进行二菌群的混合静止发酵。[结果]酵母菌与乳酸菌均能在赤霉素萃余液中生长繁殖;静止培养5 d后,赤霉素萃余液COD从100 g/L以上下降至50~60 g/L,COD降解率达50%左右,酵母乳酸菌体固含量达到10%以上。[结论]利用微生物混合静止发酵降低赤霉素萃余液中COD含量,其技术路线初步可行。     

HPLC法测定人血浆中头孢克肟的浓度

建立了人血浆中头孢克肟浓度测定方法。采用Phecda C18色谱柱,流动相:甲醇-0.075%三氟乙酸溶液(22∶78,V/V),流速:1.0 mL.min-1,柱温:44℃,检测波长:288 nm。结果显示:建立的HPLC法在0.045～4.5μg.mL-1范围内线性关系良好,定量下限为0.045μg.mL-1;相对回收率为101.2%～105.1%;提取回收率为72.7%～72.8%;批内、批间RSD均小于5%,该法灵敏、准确、精密度高,适用于临床研究。     

洪灾后高州水库表层沉积物重金属含量及污染评价

针对2010年9月21日高州水库发生特大洪灾与泥石流,2012年4月对高州水库沉积物生态环境进行评估。其分析结果表明,高州水库表层沉积物中的9种重金属元素含量的变化趋势为w(Mn)>w(Zn)>w(Pb)>w(Cr)>w(Ni)>w(Cu)>w(As)>w(Fe)>w(Cd)。地累积指数法评价表明,高州水库中重金属污染程度强弱顺序为:Cu>Zn>Pb>Ni>Cd>Mn>Cr>As>Fe。潜在生态风险指数法评价表明,高州水库部分点位Cd生态风险评级为强,应对其来源展开进一步研究,并关注其可能存在的生物效应。与高州水库洪灾前表层沉积物重金属含量相比,9.21洪灾后新形成的沉积物受到的重金属污染在减轻。     

裂解汽油加氢原料中C5总含量的测定

建立了气相色谱分析裂解汽油加氢原料中C5总含量的分析方法。方法的精密度分析结果表明,方法的实验室内相对标准偏差小于2％,实验室间相对标准偏差小于3％,而且方法的精密度与样品水平呈明显的线性关系。本方法具有很好的重复性和再现性,可以为石油炼化企业的裂解汽油加氢原料中C5总含量的测定提供统一的检测依据。     

关于水分析化学课程改革的一点思考

水分析化学是环境类非常重要的专业基础课。针对目前水分析化学课程教学中存在的问题,结合水分析化学学科的特点和规律,通过调整教学知识体系,教学模式、教学内容与考核模式,解决目前大学生内在学习动力不足的问题,激发学生的内在学习潜能,变被动学习为主动学习。     

The seeds effect on zeolite NU-87: synthesis parameters and structural properties

EU-1 and NU-87 zeolites, which possess certain similarity in structure, were used as seeds for synthesizing zeolite NU-87. The usage of seeds greatly enhanced the crystallization rate and widened the composition range of initial gel. As compared with the hetero-structural seeds, the homo-structural seeds were more favorable for the synthesis of zeolite NU-87, also resulted in extremely decreased template agent and greatly shortened crystallization time. However, hetero-structural seeds EU-1 resulted in the much smaller particle size of the as-synthesized zeolite NU-87, due to the distinct properties of seeds.