Soil phosphorus extractability and uptake in a Cirsio-Molinietum fen-meadow and an adjacent Holcus lanatus pasture on the culm measures, north Devon, UK

The seasonal pattern of extractable soil P and soil solution P was determined for topsoil samples taken from a Cirsio-Molinietum fen-meadow community, and also for an adjacent agriculturally improved pasture in Devon, UK. Phosphorus concentration was investigated using three methods during 1993; Olsen's reagent (sodium bicarbonate) for soil P, centrifuging and polymeric suction cups for soil solution P. Solutions were extracted at two-weekly intervals during the spring and at monthly intervals during the summer. Phosphorus removed from both sites by centrifuging was in the range 5–30 μg dm⁻³ soil, in comparison with 1–6 mg kg⁻¹ for Olsen P. Olsen P on the Cirsio-Molinietum was significantly lower than on the improved pasture in mid-March and mid-June. The concentration of P in soil solution removed by suction cups was below the level of detection (<2 μg dm⁻³) on the Cirsio-Molinietum. Suction cup P on the improved pasture peaked in April and May at 16–19 μg dm⁻³ soil. Herbage yield and P concentration were measured throughout the growing season. Above-ground standing crop was greater on the Cirsio-Molinietum than the improved pasture at the beginning of the grazing season, because of the large litter component on the former. Total P content of this material was only 1.81 kg P ha⁻¹ on the Cirsio-Molinietum, in comparison with 5.58 kg P ha⁻¹ on the improved pasture. Phosphorus concentration of plant material obtained by repeated defoliation was approximately 1.0 mg P g⁻¹ DM on the Cirsio-Molinietum, whereas a clear seasonal trend, peaking at 3.5 mg P g⁻¹ DM, was observed on the improved pasture. Phosphorus concentration of litter, grass and sedge from ungrazed plots on the Cirsio-Molinietum indicated distinct seasonal variations for the grass, with no seasonal pattern for the sedge component.     

DT合金滚轮体热冲压冲头复合强化工艺研究

阐述了DT合金正确的锻造方法,通过对该合金实施镀镍稀土渗硼、等温淬火、高温回火复合处理,能得到很高硬度、耐磨性及抗高温氧化和冷-热疲劳抗力,应用于喷油泵滚轮体的热冲压冲头上,使用寿命比相应的热作模具钢可提高15～20倍。     

动电电位的测试在煤泥水治理中的应用

通过对煤泥水动电电位的测试 ,推断出煤泥水的胶粒结构。通过对各种降低动电电位的混凝剂的测试 ,得出钙盐是较理想的混凝剂 ,并确定了电石渣与聚丙烯酰胺联用治理煤泥水的最新方法。     

人体硼暴露及其代谢的研究进展

硼是自然界中普遍存在的元素.一般人群主要通过饮水和食品暴露硼,硼作业工人也通过空气暴露硼.硼经人体吸收之后会很快分布于全身体液中,骨骼中的硼含量要高于血液.尿液硼浓度能够很好的反映硼的外暴露水平,可作为硼暴露的生物标志物.本文对近年来有关人体通过不同途径硼暴露及其代谢以及生物标志物的研究进展进行了总结,并对今后的研究重点给出了建议.     

土壤样品中硼的测定

对土壤样品石硼姜黄素分光光度分析,此法稳定性差,远不如铍试剂分光光度法。     

碳化硅协同分子筛负载型催化剂微波辅助催化氧化甲苯性能

实验采用浸渍法制备分子筛负载型催化剂,微波场中利用吸波材料碳化硅和催化剂催化氧化甲苯废气.考察了碳化硅与分子筛负载铜-钒催化剂混合比及混合方式等条件变化对甲苯降解的影响,并通过电镜扫描、比表面积测试和X射线衍射分析等手段对催化剂进行了表征.研究表明,在固定床反应器底部装填质量比20%的碳化硅时,反应器兼有蓄热性能和低温催化氧化的优点,可有效提高微波能的利用和甲苯的催化氧化效率;微波功率75 W和47 W作用下,分子筛负载铜-钒催化剂和负载铜-钒-铈催化剂对甲苯的完全燃烧温度分别为325℃和160℃.表征发现,稀土元素铈的掺杂提高了活性组分在催化剂表面的分散度,催化剂的微孔结构保证了其对甲苯的高吸附性能,而非晶相型铜、钒氧化物的存在则提高了催化剂的催化活性.     

硼化合物对普通小球藻的急性毒性效应

以普通小球藻(Chlorella vulgaris)为受试生物,采用批量培养法考察了不同质量浓度的硼酸和四硼酸钠对藻细胞生物量、ρ(Chla)、ρ(蛋白质)以及MDA(丙二醛)含量的96 h急性毒性效应,初步探讨了硼化合物对普通小球藻的毒性作用. 结果表明:在2种硼化合物胁迫下藻细胞的生长受到抑制,尤其是当ρ(硼)≥40 mg/L时抑制作用极其显著(P<0.01);ρ(硼)为0~80 mg/L时,硼酸和四硼酸钠对藻细胞生长的最大抑制率分别为89.42%和86.72%,硼的抑制作用呈明显的剂量-效应关系,并且随暴露时间延长而减弱,96 h时藻细胞恢复生长. 硼酸和四硼酸钠对藻细胞的96 h-EC₅₀(半数有效浓度)分别为82.03和71.19 mg/L(以硼计);与对照组相比,二者对普通小球藻的毒性效应表现为,随着暴露时间的延长,ρ(Chla)降低、ρ(蛋白质)先减后增、MDA含量升高. 研究显示,硼化合物对普通小球藻的毒性作用,可能是由于短期内引发藻细胞产生活性氧自由基并造成膜脂质和其他生物大分子的氧化损伤所致.      

Tolerance and phytoremediation potential of Calopogonium mucunoides to boron

Soil contamination by trace elements (TEs) is a problem of great concern since the industrial revolution. However, not all TEs are essentially toxic, and several micronutrients such as boron (B) play essential roles during plant development and, in this case, B acts in plants as a structural element. Soil B levels above 3.0 mg dm^–3 may be toxic to many plants and the greatest input of B to the environment occurs through the anthropic way. An environmentally promising alternative is phytoremediation, in which contaminant‐tolerant plants are used to remove or stabilize TEs in soils. Therefore, this work has been carried out to aim C. mucunoides’ tolerance to increasing B concentrations and its potential as a phytoremediator. We found out that C. mucunoides tolerates B doses up to 480 mg dm^?3, the B uptaken is transported at a 1:1 ratio between root and shoot, suggesting that C. mucunoides can be used as a phytostabilizer and phytoextractor due to its potential to be used in phytoremediation techniques because it can tolerate toxic concentrations of B.     

The Bhopal gas tragedy—A perspective

We, the then Mayor and Chief of Police of Bhopal, were the two people on whom the responsibility of handling the world's worst industrial disaster fell unceremoniously on the cold night of December 2–3, 1984 when 41 tons of MIC gas was released from the Union Carbide plant in Bhopal. With the company initially in denial mode about the release and then calling it a ‘tear-gas’ type and providing no information on antidote, and with the limited means of evacuation, handling of medical emergency affecting hundreds of thousand, identification and disposal of the thousands of dead, it was probably the most challenging task faced by a duo in peace time. The local people, the medical community, the railway staff, the NGOs, were all very helpful. We narrate the happening and the handling of the consequences and the spot decisions that had to be made with the hope that no such accident happens anywhere.     

硼铁合金烟尘静电治理试验研究

建立了针对硼铁合金烟尘治理的工况小型试验的静电实验装置，根据硼铁烟尘颗粒细，比电阻偏高，在高温下呈半流体状态的特性，如果采用常规除尘方法是难以治理的，而通过采用静电收尘新技术，对冶炼过程中产生的硼铁合金烟尘进行静电治理的试验研究，取得了良好的收尘效果，对于大型静电除尘器在硼铁合金行业的应用进行了有效的试验研究和可靠的实施依据。