Single and joint effects of acetochlor and urea on earthworm Esisenia foelide populations in phaiozem

Much attention is paid to soil health and environmental safety. Earthworms are an important indicator of soil ecosystem health and safety. Ecological toxicity of acetochlor and excessive urea, in both their single and joint effects, on earthworm Esisenia foelide was thus studied using the soil-culture method. Acetochlor had an enhanced toxicity from low concentration to high concentration. The mortality of earthworms after a 6-day exposure was changed from 0 to 86.7%, and the weight change rate ranged from 7.86 to -30.43%, when the concentration of acetochlor was increased from 164 to 730 mg kg(-1). Urea expressed its positive and beneficial effects on earthworms when its concentration was lower than 500 mg kg(-1). Strongly toxic effects took place when the concentration of urea was higher than 1000 mg kg(-1). The mortality of earthworms exposed to urea reached 100% when its concentration was more than 1500 mg kg(-1). When the concentration of urea was lower than 500 mg kg(-1), there were antagonistic effects between the two agrochemicals on earthworms; when the concentration of urea was higher than 500 mg kg(-1), joint toxic effects of acetochlor and excessive urea on earthworms were synergic. In any case, excessive urea application is very harmful to the health of soil ecosystems.     

珍稀濒危植物金花茶地理分布与生境调查研究

为了对珍稀濒危植物金花茶(Camellia nitidissima)进行有效保护,通过实地调查和相关资料分析,对其地理分布与生境进行了系统的调查研究。调查结果表明:(1)金花茶主要分布在广西西南部的防城、南宁、隆安、扶绥等县(市)。位于北纬21°30′～22°55′,东经107°36′～108°33′区域内。金花茶的垂直分布高度在12～450m之间,以海拔200～300m之间的范围较为常见。(2)金花茶为喜暖热植物,对热量要求较高,属热带性树种。金花茶不能忍耐阳光直射,为喜荫耐荫植物,要求的光合有效辐射一般小于photons12.8μmol?m-2?s-1。(3)金花茶群落植物组成种类多样,且多属热带性树种。组成群落主要科有橄榄科(Burseraceae)、山榄科(Sapotaceae)、大戟科(Euphorbiaceae)、桑科(Moraceae)、藤黄科(Guttiferae)、无患子科(Sapindaceae)、番荔枝科(Annonaceae)、梧桐科(Sterculiaceae)的种类。研究结果摸清了金花茶的地理分布和主要生态特性,为金花茶的引种驯化和种质资源的保存提供科学依据。     

长江上游典型区域丰枯转换期水资源变化分析

针对长江上游金沙江下游区域近几年6月和10月出现的较剧烈的水资源丰枯转换现象,以2018年金沙江下游来水过程作为研究案例,考虑金沙江下游流域来水组成及水利工程建设情况,从区间流量分析及上游水库群调蓄影响分析两方面开展了研究工作。研究结果表明:金沙江下游流域丰枯转换主要影响因素为三堆子流量变化,三堆子至溪洛渡区间流量变化影响较小。在6月,上游水库群调蓄对金沙江下游流域丰枯转换影响较大,10月影响相对较小。相关研究成果可为溪洛渡-向家坝梯级水库调度计划制订及实际调度工作提供参考。     

A General Model for Analyzing Data from Mark-recapture Experiments with an Application to the Pacific Halibut

A general model is developed to examine the patterns of the regional movement of tagged and released fish from mark-recapture experiments. It is a stochastic model that incorporates fishing mortality, natural mortality, fish movement, tag-shedding, and different rates of reporting. A likelihood function is constructed for estimating its parameters. We used this model to analyze data on the Pacific halibut from mark-recapture experiments conducted by the International Pacific Halibut Commission (IPHC), with a total of 36,058 releases from 1982 to 1986 and 5,826 recoveries from 1982 to 2000. We estimated their rates of movement among IPHC management areas, along with their instantaneous rates of natural and fishing mortalities. Our analysis revealed that fish movement was not significant among areas, with a resident probability of > 0.92. This lends support to the IPHC catch-at-age stock assessment model (which has no built-in movement components). The estimated instantaneous rate of natural mortality (0.198 year⁻¹) lies between that assumed in all IPHC stock assessments before 1998 (0.20 year⁻¹) and that from 1999 onwards (0.15 year⁻¹). The estimates of the instantaneous rates of fishing mortality were consistent with those from the IPHC stock assessment model. Received: April 2003 / Revised: May 2005     

甲胺磷和乙草胺对产甲烷菌种群数量及其活性的影响

采用厌氧培养箱、气相色谱技术和MPN计数法,研究了甲胺磷和乙草胺在4种浓度(0 1、0 2、0 5和1 0mg·L-1)下对水稻田土壤产甲烷菌种群数量及其活性的影响。加甲胺磷后7d内刺激产甲烷菌种群的生长,数量增加0.2～44.1倍,每管的产甲烷量增加0.8～2.1倍,且刺激作用随药剂浓度的增加而增强;加乙草胺后7d内,产甲烷菌的生长受到抑制,数量下降了50%～99%,每管的产甲烷量显著减少,且抑制作用随药剂浓度的增加而增强。随着加药时间的延长,甲胺磷和乙草胺逐渐降解,产甲烷菌数量又恢复至原有水平。     

试论江西省环境监理稽查

分析了环境监理稽查的分类和内容，结合江西省面临的环境保护问题，阐述了加强环境监理稽查工作的必要性和紧迫性。     

内燃机螺帽径向夹持下料模和镦挤孔模具设计

根据轴向应力对棒料剪断方式及其断口形状的影响,设计了对螺帽锻造所用热轧棒料能进行精密剪切下料的新型结构的径向支持下料模具.采取增加下六角冲头与凹模的配合长度及配合精度的导向方法,设计了在80吨非标压力机上锻带孔螺帽的成形模具.给出了两种模具的试验结果.     

多管旋风除尘器热态除尘效率的影响因素

根据对多管旋风除法器热态除尘效率大量测试实践，讨论了影响多管风除尘器除尘效率的制造质量，整体安装要求、运行管理及锅炉运行等因素，建议在应用推广中应予以重视。     

影响微生物絮凝剂生成的条件研究

从污水中筛选到了一株絮凝活性较好的絮凝剂产生菌 ,分别研究了碳源、氮源、供氧量、培养温度等条件对其产絮凝剂的影响。结果表明 ,葡萄糖、淀粉是较好的碳源 ,蛋白胨等有机氮作氮源较好 ,供氧量较大有利于产絮凝剂 ,最适宜培养温度为 30℃ ,最佳pH为 6 .5～ 7.5。     

海洋原位化学探测核心技术的研究应用

化学传感器和化学分析器是海洋原位化学探测系统中的核心技术。本文从电化学、光纤化学和湿法化学分析等三个领域介绍了国际上化学传感器和化学分析器的研究和应用现状 ,比较了部分化学传感器和化学分析器的性能指标和优缺点 ,指出了海洋原位化学探测技术的发展趋势。与国外海洋原位化学探测技术的研究相比 ,我国在这方面的研究基本上还是空白 ,海洋原位化学探测技术已成为我国亟待发展的海洋高新技术之一。