海河河口水和新港港湾水中α-六六六对映体选择性降解及α、β、γ、δ-六六六浓度

 运用全甲基化β-环糊精毛细管气相色谱手性柱，首次测定了我国天然水体中手性污染物_α-六六六的对映体浓度比值〔ER＝（＋）_α-六六六／（－）_α-六六六〕。初春和初夏季节天津新港港湾海水中_α-六六六的ER值为0.91～0.80，证实了该水体微生物对_α-六六六的降解存在着对映体选择性，（＋）_α-六六六被优先降解。海河河口水在以上两季节中，_α-六六六的ER值均近似为1，其原因有待于进一步研究，可能是附近有经常排放外消旋体_α-六六六的污染源。另外还测定了以上两水体中α、β、γ、δ-六六六的浓度，两水体中的六六六含量分别符合我国Ｉ类海洋水质标准（GB3097-82）和生活饮用水水质标准（GB5749-85）。     

在役压力容器声发射源严重度的多级模糊综合评定方法研究

根据国内外有关在役压力容器声发射检测评定标准、文献以及我们多年的检测和评定经验，利用模糊数学中的隶属度概念和多级模糊综合评价理论，在研究多种检测信息对评定结果影响程度的基础上，提出了声发射源严重度的多级模糊综合评定方法，并初步应用于大型球罐声发射检测评定，取得好的效果     

风浪扰动中太湖OA对水体磷循环影响的原位实验研究

在一次风速12 m.s-1的强风浪过程中,对太湖梅梁湾一浅水区水体有机聚集体（organic aggregates,OA）丰度、颗粒态有机质含量、碳、氮和磷含量等基本理化性质的变化情况进行了连续的原位监测和分析,同时分析了基本的水质指标.结果表明,风浪过程会对水体OA的理化性质及水体的磷循环产生极大的影响：在风浪过程中...     

天然淡水表面微层中某些重金属富集现象研究

自制成玻璃板表面微层水采样器,采集厚度可达30至55μｍ,表面微层水中颗粒物采集率为45.3％±2.2％,性能合乎要求。应用于天津水上公园表面微层湖水,以AAS和ICP法测定其中铜、铁、锰、锌的含量,与相应采样点下层湖水相比,4种重金属在表面微层水中的富集倍数为2至88,富集显著,并与采样站位等有关。     

营养液钙源对微生物固化砂土效果影响的试验研究

微生物诱导碳酸钙沉淀(MICP)作为一种环保型地基处理技术,其机理是通过微生物诱导碳酸钙沉淀有效改善土体工程性能,参与固化反应的营养液成份不同对固化效果有显著影响。分别选用氯化钙和硝酸钙作为营养液中的钙源,通过渗透实验、干密度实验、吸水率实验、无侧限抗压强度实验从宏观角度分析钙源对微生物固化砂土物理力学指标的影响。同时,结合电镜扫描测试,从微观角度对比了不同钙源作用下碳酸钙沉淀晶体形态及空间分布的差异。研究结果表明:利用硝酸钙固化后的砂柱整体密实度更高,其破坏裂缝在饱水和干燥状态下比氯化钙固化后的砂柱更小;硝酸钙作为钙源固化后的砂柱渗透系数和吸水率更低,干密度和无侧限抗压强度也更高。电镜扫描结果显示,氯化钙为钙源形成的碳酸钙沉淀量较少,形态为球状,散落分布在砂粒表面;硝酸钙形成碳酸钙沉淀量较多,形态以球状或者立方体为主,包裹住砂颗粒,团聚效果更为明显。因此,就钙源而言,硝酸钙的微生物固化效果较氯化钙更好。     

饱和砂土循环液化模式影响因素试验研究∗

通过室内试验探讨了振动频率、骨架相对密实度、填料含量及成分对砂土循环液化强度及液化模式的影响。 针对相对密实度分别为 35%、50% 和 80% 的砂骨架中添加 0%、5%、8%、10%、15% 和 20% 等不同质量的填料(粉土、粉质黏土)进行了循环扭剪试验,循环加载频率为 0.1、1 Hz。结果表明：砂土循环液化模式与振动频率密切相关,振动频率较高时,呈现显著的软化特征和流滑现象,振动频率较低时,呈现剪胀和循环活动性;循环液化模式与骨架相对密实度密切相关,填料含量及填料成分对动强度具有较显著的影响,但填料含量在一定范围内并不影响循环液化模式,填料成分对循环液化模式产生一定影响。     

Diurnal Profile of Particle-bound Polycyclic Aromatic Hydrocarbon (pPAH) Concentration in Urban Environment in Tokyo Metropolitan Area

Traffic emits particles under 1 m. The particles arethe most responsible to particle-bound polycyclic aromatichydrocarbon (pPAH) which can impact human health. To assessthem as health hazards, we monitored diurnal changes in theconcentration and distribution of pPAH near roads in Tokyo.The total pPAH concentration was determined using aphotoelectric aerosol sensor (PAS) which ionized PAH-adsorbingparticles. The total pPAH concentration was compared withchemical analyses by gas chromatography/mass spectrometry(GC/MS). Two sampling sessions, one in August and one inSeptember 2000, were done at three sampling sites at the Hongo Campus of the University of Tokyo. Monitoring was every two minutes for six consecutive days for the first session and for seven consecutive days for the second session.Correlation of the pPAH concentration with traffic flow andwith meteorological conditions were also assessed. The pPAHconcentration varied in the same manner on all days: it sharplyincreased in the early morning by a sudden burden of traffic, and it rapidly decreased during the daytime, probably owing tophotodegradation and/or dilution by rising in the mixingzone. The local wind field, and consequently thetransportation of pPAH from the road, were stronglyinfluenced by the configuration and location of thesurrounding buildings. The pPAH clearly changed in 1- and0.5 day cycles, particularly at the roadside.     

Experimental study on effect of anion surfactant on degradation rate of aldicarb in soil

Degradation kinetics of aldicarb [2-methyl-2-(methylthio) propionaldehyde O-(methyl carbamoyl) oxime] in surface and subsurface soil containing different levels of sodium dodecylbenzenesulfonate (SDBS) were determined to understand complex effect of SDBS on aldicarb degradation process. The results showed that degradation curves of aldicarb in soil can be described with first order kinetics formula and the degradation rate constant. k (d(-1)), in surface soil was larger than that in subsurface soil. SDBS can accelerate the degradation of aldicarb in soil and there was a good linear relationship between degradation rate constant and the logarithm of SDBS concentration. The possible reasons were that SDBS could change pH value of soil, have solubilization effect on aldicarb, and be used as carbon source of microorganisms. But SDBS had a larger promotion to the degradation of aldicarb in surface than in subsurface soil. When SDBS concentration was 1000 mg/kg of dried soil the first order degradation rate constant of aldicarb could be increased by 56.6 percent in surface soil and by 27.6 percent in subsurface soil, respectively.     

Electrocatalytic conversion of nitrate waste into ammonia: a review

Environmental Chemistry Letters - The electrocatalytic reduction of nitrate waste into ammonia allows both the removal of nitrate contaminants and an alternative production of ammonia compared to...     

Research progress of the POP fugacity model: a bibliometrics-based analysis

Environmental Science and Pollution Research - With the emergence of environmental issues regarding persistent organic pollutants (POPs), fugacity models have been widely used in the concentration...