铜对圆锯片热应力的影响与研究

通过锯切木材试验,分别对锯身槽上嵌铜和不嵌铜设计的同条件下木工圆锯片,进行定点温度、横向摆动量和噪声参数的测量;并结合有限元热应力场分布与计算,以及铜材理化试验分析等手段,得出其嵌铜锯片消除热应力性能好,振声性能较高,锯片使用寿命延长等结论,并提出减振降噪的措施与建议,为优化圆锯片的设计工作提供参考依据。     

Critical body residues (CBRs) for ecotoxicological soil quality assessment: copper in earthworms

The term ‘critical body residue’ (CBR) was defined as the lowest observed total body concentration of a contaminant in an organism, which is associated with the occurrence of adverse toxic effects in either individuals or populations of a defined age or stage of development. In this study, internal toxicity thresholds were determined for copper in the clitellated adult stage of earthworms (Lumbricus rubellus and Aporrectodea caliginosa). The objective was to assess the applicability of CBRs as a practical tool in soil quality assessment of contaminated sites and as a means of a sustainable protection of earthworm fauna. Laboratory studies showed that body concentrations of Cu were generally in agreement with the chemically available CaCl₂-extractable fraction in soil, but that there was also some evidence of internal pH-related homeostatic regulation. Toxicological correlates of body Cu concentrations with adverse effects on cocoon production (fecundity) suggested an approximate sublethal internal threshold of about 40 mg kg⁻¹, with mortality occurring at about 60 mg kg⁻¹. Adult L. rubellus sampled from areas with a wide range of metal pollution showed body Cu concentrations with a minimum of 8 mg kg⁻¹ and a maximum of 60 mg kg⁻¹. Beyond this apparent physiological tolerance range, environmental management directed at optimal earthworm population survival may not be sustainable in contaminated fields. Studies of L. rubellus colonizing a metal-contaminated experimental sludge-treated field showed that a reduced rate of colonization can already be associated with an average body Cu concentration of 25 mg kg⁻¹. However, in this particular field situation mixture effects of other metals that were also present in the soil and the occurrence of avoidance behaviour during colonization may have contributed to this low internal toxicity threshold. It is concluded that the CBR approach seems to be a feasible option for use as a tool in a bioavailability-based soil quality assessment, even for essential trace metals like copper, but that further insight may be needed to establish the uncertainty and reliability of the application in environmental quality assessment and decision making.     

Copper in the terrestrial environment: Verification of a laboratory-derived terrestrial biotic ligand model to predict earthworm mortality with toxicity observed in field soils

This study was set up for validation of a regression model to predict mortality in the terrestrial earthworm Aporrectodea caliginosa following exposure to copper. This model was derived from a terrestrial biotic ligand model and incorporates the protective effects of H⁺ and Na⁺ on copper toxicity.Three soil sets were used for the experiments, all of which had a different copper contamination history over more than 20 years and were considered to be aged field soils. The soils were characterized by analysis of various copper pools in the solid phase and in the pore water, analysis of physical and chemical soil properties and by regression analysis. Measured and calculated copper activities (expressed as pCu) correlated reasonably well. Measured copper activities correlated with the total copper concentration in the pore water and the pH. The organic matter in the solid phase had no influence on the pCu in these soil sets.Earthworms were exposed to the soils for 28 days, after which survival was scored. Observed earthworm mortality after 28-days exposure was plotted as a function of the log-transformed difference between predicted (log₁₀ transformed) LC50-values and measured values of pCu for validation of the regression model. The results obtained were in agreement with the assumption that mortality is to be observed in those soils where the predicted LC50 exceeds the measured pCu. However, a structural underestimation of toxicity was apparent, which is most likely due to mixture effects related to the presence of additional substances in field soils. Nevertheless, the trend of the results in the validation tests demonstrates that the newly developed toxicity model is a useful tool in predicting lethality of copper contamination to earthworms in field soils.     

铜污染对高等植物的生理毒害作用研究

本文综述了当前国内外Cu污染对高等植物生理毒害的研究近况,探讨了Cu过量对植物光合作用、细胞结构、细胞分裂、酶学系统和其他营养元素的吸收等的影响,并探讨了该方面研究存在的不足及其展望。     

狗牙根平脐蠕孢菌生物学特性及药剂筛选

 对狗牙根平脐蠕孢菌的生物学特性及5种杀菌剂对该病原菌的抑制作用进行了研究。结果表明：狗牙根平脐蠕孢菌对多种碳、氮源都能利用,以蔗糖和硝酸钾、L-天冬酰胺最好,但以脲为氮源的培养基生长较差。菌丝最佳生长温度是25~30 ℃之间，在25 ℃时最利于产孢,菌丝生长和分生孢子的致死温度是56 ℃；该菌在pH 3~11范围内均能生长，产生分生孢子，菌丝生长的最适pH 5~7，产孢量最大的pH是 3，9，10；糖浓度在2%~8%菌丝能生长，在糖浓度为2%时菌丝生长最好，产孢量最高；光照对病原菌的菌丝生长和产孢有明显影响,在全光照的条件下有利于菌丝的生长，但不会产孢，黑暗12h光照12h既利于菌丝生长又利于产孢，而全黑暗的条件下不利于菌丝生长和产孢。对5种杀菌剂的研究表明：退菌特和百菌清对狗牙根平脐蠕孢菌菌丝生长的抑制效果较好，其它杀菌剂也能有效的抑制菌丝的生长。     

四川稻区几种重要病虫抗药性评估

在四川稻区多年的监测结果表明:水稻二化螟对杀虫双、杀虫单已达中等抗性水平至高抗水平(41 97～371 9倍),对三唑磷的敏感性降低;稻飞虱对吡虫啉相对敏感,对噻嗪酮、敌敌畏的敏感度降低;稻瘟病对异稻瘟净产生了抗性,抗性菌株频率为20 51%～56 41%,对稻瘟灵的敏感性降低,抗性菌株频率为3 52%～9 52%,对三环唑的敏感性也有下降的表现,病斑出现率为0 4%。水稻几种重要病虫的抗性风险较大,其抗性治理势在必行。     

三唑酮防治小麦雪霉叶枯病的研究

三唑酮100μg/mL可完全抑制小麦雪霉叶枯病菌分生孢子萌发,25μg/mL即可引起90％芽管畸变。离体叶碟法和盆栽幼苗法测定表明,三唑酮有较强的保护作用和治疗作用。田间药效试验确认该剂能有效地控制成株叶斑和叶枯。在小麦条锈病流行区,可用三唑酮常规喷雾,兼治该两种病害。田间用药量应不低于10～15g/亩。     

不同杀菌剂对立枯丝核菌的室内毒力测定

采用生长速率法在室内测定了6种杀菌剂对棉花立枯丝核菌(Rhizoctonia solani)的毒力作用.结果表明,6种杀菌剂对棉花立枯丝核病菌菌丝生长均有一定的抑制作用,其中甲基立枯磷对立枯丝核菌的抑菌效果最佳,抑制中浓度(EC50)为0.042 mg/kg,其次为多菌灵,EC50为0.044 mg/kg.相关分析表明药剂浓度与抑制作用呈正相关.     

锌、铜对水稻幼苗生长及超氧物歧化酶的影响

通过使用缺Ｃｕ或Ｚｎ与缺Ｃｕ、Ｚｎ的木村Ｂ营养液培养耐性品种ＩＲ８１９２—３２—２和敏感品种ＩＲ２６幼苗至七叶期，缺Ｃｕ的稻苗只是新生叶叶尖枯黄，扭曲。而缺Ｚｎ与缺Ｃｕ、Ｚｎ的稻苗叶脉间全部褪绿，根系衰退。缺Ｚｎ与缺Ｃｕ、Ｚｎ的稻苗叶绿素含量、根长、株高和可溶性蛋白含量显著低于对照，且不耐性品种降低的幅度大。凡是缺素培养的稻苗，根和叶的ＳＯＤ活性均显著减弱。     

铜、镉、敌敌畏和甲胺磷对南美白对虾幼虾的急性致毒及相互关系

在恒温(25±1℃)和充气条件下,研究了铜、镉、敌敌畏和甲胺磷对南美白对虾的急性致毒效用,得到了铜、镉、敌敌畏、甲胺磷对幼虾的24hLC50、48hLC50、72hLC50、96hLC50,四种毒物的安全浓度分别为0.008、0.001、7.6×10-4、7.8×10-4mg/L,四种毒物的毒性大小顺序为甲胺磷＞敌敌畏＞Cd2+＞Cu2+.铜与敌敌畏、甲胺磷对南美白对虾幼虾的联合毒性作用为相加作用,镉与敌敌畏、甲胺磷的联合毒性作用为拮抗作用.