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761.
随着我国城市化进程的不断加快 ,城乡结合部经济、社会飞速发展。在发展过程中 ,城乡结合部环境污染和资源破坏问题日益突出 ,为此 ,必须完善城乡结合部环境保护立法和执法 ,切实做好环境规划工作 ,实现环境保护与经济、社会的协调发展。  相似文献   
762.
叙述了进行陶瓷-钢反挤压组合凹模优化设计的方法,编制了相应的优化设计程序,分析了优化设计的结果,在此基础上提出了陶瓷-钢组合凹模设计的若干准则.  相似文献   
763.
Using the exposure simulation experiment, the action of petroleum affecting the accumulation of the trace metals including copper (Cu) and cadmium (Cd) in littoral polychaete Nereis diversicolor collected from the Shuangtaizi Estuary in Liaoning Province, China was examined. The results showed that there was a markedly non-linear relationship between the accumulation of Cu in worms and the experimental concentration of Cu in exposure solutions when the concentration of petroleum remained at 0, 100, and 220 μl/L, respectively. However, significantly non-linear relationship for worms exposed to Cd was observed only when the concentration of added petroleum was 0 and 220 μl/L. The accumulation of Cu in worms did not differ significantly among the three different levels of petroleum concentrations combined with various concentrations of Cu. So was the accumulation of Cd in worms (p〉0.05). However, the addition of petroleum in exposure solutions brought about an increase in the accumulation of Cu in Nereis diversicolor, in comparison with single Cu pollution. On the other hand, when the concentration of added petroleum remained at 100 μl/L, the accumulation of Cd in worms was lower than that in worms exposed to various concentrations of only cadmium. However, the worms exposed to Cd and petroleum 220 μl/L did not show obvious and identical increase in the accumulation of Cd, compared with single Cd exposure. The accumulation of both Cu and Cd in worms did not increase significantly with the increases in concentrations of Cu or Cd in exposure solutions combined with petroleum (0, 100, and 220μl/L) under the experimental conditions. Although Nereis diversicolor is exposed to very high Cu and Cd in exposure solutions, accumulation and detoxification mechanisms are sufficient to cope with the extra metal influx in order to survive.  相似文献   
764.
降尘、酸雨及其复合污染对蔬菜产量和品质的影响   总被引:3,自引:0,他引:3  
盆栽试验结果表明,降尘、酸雨可降低酸性紫色土莴笋茎、叶鲜重3.9%—14.4%;复合污染对莴笋的减产量增大,且以酸性紫色土为高,降尘、酸雨对蔬菜的促长作用使莴笋早衰减产、小白菜增产。酸性紫色土各处理较对照明显提高两种蔬菜叶细胞透性(电导值、K~+外渗增量达9.5%—127.7%),作物种类间变化规律不同。复合污染明显使两种蔬菜V_c和水溶性氨基酸降低、莴笋硝酸盐增高,蔬菜品质变劣。,酸性土r=0.9646-0.9739)。同产量结果相似,酸性紫色土上蔬菜的根重绝对量大大低于石灰性紫色土。可见在pH5.2的酸性紫色土上不宜种植抗逆(酸)性差的蔬菜作物,尤其是在降尘-酸雨复合污染条件下更是如此。否则,必将形成一个典型的逆境农业生态系统。2.3降尘、酸雨及其复合污染对蔬菜叶片细胞透性的影响降尘、酸雨各处理使酸性紫色土上莴笋叶片电导值、K+浓度较CK分别提高27.7%—59.0%和9.1%—27.3%(表5),表明叶细胞膜可能受到不同程度损伤,膜内物质容易外渗[12],影响植物正常生长、降低产量,石灰性紫色土虽3个处理植株叶片电导值也明显高于CK8.4%—59.7%,但K+浓度下降8.0%—25.0%(A处理除外),  相似文献   
765.
哈尔滨市粪便无害化处理厂工艺设计   总被引:3,自引:0,他引:3  
介绍了哈尔滨太平区粪便无害化处理厂的基本工艺流程和相关设备和构筑物。该厂将粪便进行机械脱水,脱水粪渣添加麦壳或玉米秸经两次好氧堆肥处理,添加无机肥料生产有机复合肥;粪水厌氧消化生产液体肥料的工艺对粪便进行资源化利用,产生臭气通过除臭装置吸收。该工程改善了当地的污染状况并创造了经济效益。  相似文献   
766.
Baur  Robert  Feeny  Paul 《Chemoecology》1994,5(1):26-36
Summary Antennae of femalePapilio butterflies perceive many volatile plant constituents with widely differing, constituent-specific sensitivities. We compared the responses of threePapilio species to volatiles from host and non-host plants to assess species-specificity and the degree of evolutionary conservatism in olfactory responses.Since previous studies had demonstrated that the polar constituents in odor fromDaucus carota stimulate oviposition behavior inPapilio polyxenes, we collected headspace volatiles fromD. carota, Pastinaca sativa (both Apiaceae) andArtemisia dracunculus (Asteraceae) and separated the polar fraction of these volatiles by gas chromatography. GC-coupled electroantennograms (GC-EAG) were recorded from the speciesPapilio polyxenes, P. machaon hippocrates andP. troilus. In addition, the responses of the three species to five compounds known as generally occurring constituents of plant odor were recorded. The relative sensitivities for these compounds were nearly identical in all threePapilio species. The response spectra to the separated plant volatiles also showed considerable similarities among the species.From the limited set of GC peaks evoking a response in one of the species, 64% (D. carota), 44% (P. sativa) and 29% (A. dracunculus) also evoked a response in both of the other species. The responses of the two closely related Apiaceae feeders (P. polyxenes, P. m. hippocrates) to volatiles fromD. carota were more similar to each other than was either to the response ofP. troilus, which feeds on Lauraceae. However, this was not true for the responses to volatiles fromP. sativa. The least congruence among the three species was found in the responses to volatiles fromA. dracunculus, a non-host for all of them. The differences and similarities found in the response profiles of the threePapilio species are discussed with respect to evolutionary adaptation to host odor versus evolutionary conservatism in adaptation of olfactory receptors.  相似文献   
767.
介绍了采用冲压 旋压复合工艺成形静触头座的过程。其中包括 :变薄旋压成形薄壁筒体 ,扩口翻边成形法兰 ,普旋方式成形异形管口等。对主要工艺参数如主轴转速、进给率、旋轮形状、道次变形率、模板形式等作了简要介绍。该成形工艺对同类异形回转体有一定参考意义。  相似文献   
768.
ABSTRACT: A combined sewer system is a complex system subject to the dynamic stimuli of precipitation, runoff pollution loads, and sanitary wastes. The system response is a random series of pollutant loads to a receiving water. In many localities, these discharges create considerable water quality problems. Mathematical models can and have played a useful role in predicting the behavior of combined sewer systems and evaluating abatement strategies. Based on the authors' experiences over the past several years, this paper explores some of the positive and negative aspects of using deterministic mathematical models to simulate the behavior of combined sewer systems. A case study follows a discussion on modeling objectives, limitations of modeling, model selection, establishing model credibility, and many other considerations necessary in modeling and simulating these systems.  相似文献   
769.
UV/H2O2催化氧化去除微囊藻毒素-LR   总被引:6,自引:0,他引:6  
研究了UV/H2O2氧化降解微污染水体中微囊藻毒素MC-LR的效果,探讨了各种因素如H2O2浓度、pH值、光强、MC-LR浓度及反应时间对降解的影响.UV和H2O2氧化去除MC-LR具有协同作用,H2O2在UV照射下产生的羟基自由基对MC-LR有很强的氧化能力.MC-LR的降解过程可用准一级反应速率方程和二级反应速率方程拟合.反应速率常数随MC-LR的起始浓度增加而减少,反应半衰期随MC-LR的起始浓度增加而延长.在H2O2浓度为1.0 mmol/L、反应温度为(25.5±1)℃、pH值为6.8、光强2.5×104 lux及反应时间60 min的条件下,质量浓度为0.203 mg/L的MC-LR的去除率可以达到80.8%.结果表明,UV/H2O2氧化体系能有效地降解MC-LR.  相似文献   
770.
复合诱变原生质体选育重金属去除菌   总被引:6,自引:1,他引:5  
选用紫外线和亚硝酸对产朊假丝酵母CR-001进行单因子和多因子诱变处理,通过复合诱变得到了6株具有高重金属抗性的高效重金属去除菌.经过传代后CRC2811-1和CRC7-2的抑菌圈直径减至1.7mm和1.2mm;对Cr6+的去除率分别从80.2%和81.2%提高到了95.2%和94.7%.其余4株突变株的抗性和除铬性能均可保持稳定.此外,利用扫描电镜、透射电镜和原子力显微镜等仪器对吸附铬前后细胞内外的变化情况进行分析,探讨了突变菌株除铬性能改善的机理.  相似文献   
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