两级CSTR亚硝化启动及稳定运行试验研究

采用两级CSTR反应器对实际生活污水亚硝化的启动过程及稳定运行主要影响因素进行了研究.通过向生活污水里投加(NH₄)₂SO₄来提高进水氨氮浓度,并逐渐调整两级反应器的曝气强度至DO浓度分别为(1.5±0.12),(0.35±0.1) mg/L,历经45d即实现了亚硝化的启动,亚硝化率保持在90.3%以上,氨氧化率保持在91.2%以上.低氨氮生活污水运行时,通过第一级反应器中三组DO/ALR的效果对比,表明DO/ALR在1.2~2.0 mg O₂/(gN·d)时亚硝化效果最好.降低氨氮浓度以及增大HRT两种情况下导致ALR改变时,维持上述DO/ALR范围依然可以保证亚硝化的稳定.     

富氧条件下等离子体协同改性NaY分子筛催化分解NOx 研究

用不同浓度的Cu、Ce和La离子交换NaY分子筛,对比了不同改性条件下等离子体协同分解NOx的性能.实验结果表明:Cu是NOx催化分解的主要活性组分,对于8%Cu-NaY催化剂,当放电电压为10 kV,放电功率为7.6 W时,NOx转化率可达46.3%,反应产物中没有NO2,只有11 ppm的N2O.Ce的加入可以有效提高催化剂催化活性,对于5%Ce-8%Cu-NaY催化剂,当放电电压为7.8 kV,功率为3.6 W时,NOx转化率可达67.3%.La的加入同样可以使催化剂活性上升,但不同La含量催化剂的NOx转化率相差较小.     

Gonad morphology and oocyte development in<Emphasis Type="Italic"> Pseudocalanus</Emphasis> spp. in relation to spawning activity

Gonad maturation processes were studied in Pseudocalanus spp. females from Georges Bank and Cape Cod Bay (northwest Atlantic) using a combination of morphological analysis and experiments. For light microscopy of the oocytes, females of different maturation stages were preserved immediately after capture. The maturation processes during the spawning cycle were described from observations of live females which were exposed to feeding and starvation at two temperatures, 8 and 15°C, for 12 days. The gonad morphology of these females was examined in 24 h intervals, and spawning events were recorded. Both light microscopy and whole animal observation revealed that oocytes during maturation change in shape and size, in the morphology of the nucleus, and in the appearance of the ooplasm. Due to these modifications of oocyte morphology and due to oocyte migration, the morphology of the gonads changed distinctly during a spawning cycle. Five oocyte development stages were identified by light microscopy and related to a macroscopic system of four gonad development stages, that can be applied to whole animals and allows the identification of females ready to spawn. The experiment showed that food and temperature had strong effects on gonad maturation processes. High proportions of mature females were found when food was available, whereas the proportion of immature females increased shortly after exposure to starvation. Compared to 15°C, gonad maturation at 8°C was prolonged and thus spawning frequency was lower. The final maturation processes at food saturated conditions were slower than the embryonic development, and no indication was found that mature oocytes are stored in the diverticula waiting to be released. The duration of the interspawning interval would thus be determined by the duration of final oocyte maturation which is dependent on both temperature and food supply.Communicated by O. Kinne, Oldendorf/Luhe     

大气降水中重金属离子特征研究

大气降水中重金属离子的研究可以反映大气污染、地表水污染的信息.通过对国内外大气降水中重金属研究现状的阐述和大气降水中重金属的来源进行理论分析,并利用实地大气降水采样分析,归纳出其中重金属的特征,监测当前大气的污染状况,从而为区域性的大气中重金属的污染评价及污染治理提供理论依据.降水中的重金属元素主要包括Pb、Mn、Zn、Cu、Cd、Cr等,通过分析测定可以为利用大气降水作为重要饮用水补给源的区域提供饮水安全保障.     

不同类型除尘器改造为脉冲除尘器技术

介绍了除尘器改造的原则、技术和方法,并结合多个除尘器改造的工程实例,分享了不同类型除尘器改造为脉冲除尘器成功经验。经过改造的除尘器能够满足集气吸尘罩处风量的要求,减少了除尘器出口排放浓度,降低了除尘器的运行阻力。     

中国东北、内蒙古地区茶藨属果树资源的研究

本文对东北、内蒙古地区茶属果树资源进行了调查,初步查明有１９种、２变种、１变型,并对其特征、特性、生境、分布及利用价值进行了研究,总结了驯化栽培的研究结果,提出了开发利用的建议。     

Cercaricidal activity of some essential oils of plants from Brazil

Extended screening tests on the cercaricidal activity of various plants from northeast Brazil have shown that the extracts of the leaves and fruits ofPiper marginatum,Protium heptaphyllum, andCapsicum annuum show a remarkable effect on the cercaria ofSchistosoma mansoni. In the case of the oils ofPiper marginatum andCapsicum annuum, 90–96% of the cercaria ofSchistosoma mansoni were killed within 15 min. According to the NMR spectra, the active principles of the extracts seem to be water-soluble unsaturated compounds from the oils or their hydrolysis products. Natural substances provide an attractive alternative for preventive actions against schistosomiasis, as the perturbation of the ecological equilibrium of natural waters can be avoided in this manner.     

Prenatal diagnosis and psychological distress: Amniocentesis or chorionic villus biopsy?

The psychological reactions of 211 women undergoing prenatal diagnosis (PND) with amniocentesis (group A, n = 122) or chorionic villus biopsy (group V, n = 90) were exmained by questionnaires and interviews. The distress experienced while waiting for the test, during the test procedure, and while waiting for the result was reported by the women, both in questionnaires and in interviews. In the questionnaires, no difference between the two diagnostic methods was observed. In the interviews, however, the women undergoing amniocentesis appeared significantly more distressed by the procedure. In group A 97 per cent and in group V 100 per cent wished a method which, like chorionic villus biopsy, could be used in the first weeks of pregnancy. The risk of miscarriage was, as described in other studies, regarded as a serious threat by the pregnant women.