二种高硫煤中硫氮化学形态的研究

利用ＸＰＳ技术研究了贵定煤和西班牙Ｍｅｑｕｉｅｎｚａ煤中硫和氮化学形态的分布，并结合硫Ｋ－边ＸＡＮＥＳ和Ｍｏｓｓｂａｕｅｒ谱着重考察贵定煤中硫化学形态。结果表明，贵定煤中含硫化合物主要以噻吩形态存在，其次为有机硫化物；而Ｍｅｑｕｉｅｎｚａ煤中以有机硫化物含量最大，噻吩硫次之，有关含氮化合物，Ｍｅｑｕｉｅｎｚａ煤以吡咯和吡啶氮为主，但在贵定煤中观察到较大浓度的氧化氮化合物。     

Ladybird defence alkaloids: Structural,chemotaxonomic and biosynthetic aspects (Col.: Coccinellidae)

Summary The defensive mechanisms which protect ladybird beetles (Coccinellidae) against predators are reviewed. Besides behavioural mechanisms, such as thanatosis and reflex bleeding, chemical defence mechanisms are playing a prevalent role. Indeed, ladybirds are protected not only by their smell, but also by repulsive alkaloids, most of which are considered to be of autogenous origin. In a few cases, dietarily-acquired substances are also involved. Particular emphasis is laid on the repellent alkaloids which are contained in the haemolymph of many species. The structures of 34 nitrogen-containing compounds isolated so far are presented, and their distribution within the family is discussed in the light of the most widely accepted classification of these beetles. To conclude, the mode of release of the alkaloids, their variation through the life cycle and their repellent and toxic properties are discussed, as well as the few biosynthetic data yet available.     

Time course of pyrrolizidine alkaloid sequestration in <Emphasis Type="Italic">Longitarsus</Emphasis> flea beetles (Coleoptera,Chrysomelidae)

Summary. Several species of Longitarsus take up, metabolize and store pyrrolizidine alkaloids (PAs) from their host plants. In feeding experiments using radioactively labeled PAs of different types we examined the time course of the sequestration process in L. jacobaeae and L. aeruginosus. We found that adapted species efficiently store PAs for at least two weeks without major losses. During that time, there is virtually no change in the ratio of tertiary alkaloids to stored non-toxic N-oxides, regardless of chemical form fed to the beetles. This implies a transient N-oxidation process where the alkaloids are only temporarily accessible to the enzyme. A dissection experiment with L. aeruginosus six days after uptake of labeled PAs showed that the tertiary alkaloids are not found in the hemolymph but are stored in the elytra and other body compartments. This conforms with earlier experiments that localized the enzymes site of action in the hemolymph. Furthermore we show that different total alkaloid doses in the diet of L. jacobaeae and the potentially less adapted L. succineus do not affect the ratio of recovered N-oxides to tertiary molecules. Thus, the efficiency of the N-oxidizing enzyme is not dependent on the concentration of alkaloids offered.     

Concentration Evolution of Gas Species within a Collapsing Bubble in a Liquid Medium

In this study numerical methods are used to investigate the relationship between chemical concentration of gas species within a cavitating bubble, equilibrium radius of the gas bubble and pressure variations in the ambient liquid. For this purpose, governing equations are developed to describe the dynamic equilibrium of a bubble in a flowing fluid and mass transfer between gas and liquid phases, where it was assumed that gases undergo isothermal compression, obey the ideal gas law, Henry law. It is further assumed that the concentration of each phase within the bubble is uniform. The resulting nonlinear equations are solved using implicit Trapezoidal method with Newton iteration. Four gas species are modeled under various initial and ambient pressure variation conditions. These conditions maybe considered to represent typical cavitation events. The numerical results obtained are presented in terms of dimensionless numbers. These results indicate that chemical damage maybe an important component of cavitation surface damage, since high concentration profiles may develop within a collapsing bubble. Proposed formulation and numerical solutions are simple and cost effective to implement. The results presented in this study maybe used to benchmark experimental investigations or other more complex solutions, which are outside the scope of this study.     

A preliminary study of the phycological degradation of natural stone masonry

For many years it has been realised that the weathering of stone is not merely determined by physical and chemical factors but also by biological agents. When the stone in question is a historic building or monument, the damage done constitutes an irretrievable loss of our heritage and history. Laboratory studies have commenced in Paisley to study the effect of photoautotrophs on the major sedimentary rock forming minerals, with a view to expanding this work to study the overall effect of these micro-organisms on heritage masonry. Tests were carried out on Albite, Calcite, Dolomite, Orthoclase, Siderite and Quartz, using axenic cultures of the following: Chlorella vulgaris, Chlorococcum tetrasporum, Scenedesmus obliquus, Oocystis marsonii, Stichococcus bacillaris. The rock chips were immersed in either water or bolds basal media and exposed to a mix of the micro-organisms listed above and then tested weekly for their pH, fortnightly for the waters chemical composition using inductively coupled plasma-atomic emission spectrometry (ICP-AES) and visually utilising the universitys SEM facilities. Work so far has revealed biologically mediated etching of minerals, a well-defined pH profile over a period of 90 days, as well as a variety of elemental release patterns for the different minerals.     

KClO3对龙眼产期的调控效应

以自行配制、主要有效成份为KClO3的龙眼产期调控剂进行田间试验．结果表明：催花土壤施用剂量以每平方米树冠面积180g效果最佳；不同品种龙眼对药物的敏感程度不同，以石硖、储良龙眼最为敏感，平均抽花率可达80％以上．不同季节和不同梢期施药，龙眼抽花率存在显著差别；药剂干施回泥后淋水、干施淋水后回泥和拌水淋施这3种土壤给药方式的促花效果差异不显著；反季节与正造栽培收获的龙眼相比，果实质量存在一定差异，春季收获的果实个大肉厚，外观较佳，但糖份含量等品质指标则较差．KClO3调控龙眼产期的效果明显，配合相应的树体管理和土壤水分养分调控措施，可实现龙眼产期的人工合理控制．表7参20     

Herbicide exposure affects the chemical recognition of a non native predator in common toad tadpoles (<Emphasis Type="Italic">Bufo bufo</Emphasis>)

Summary. In amphibians and fishes, evidence is increasing that chemical cues from injured conspecifics can play a role in the chemical labelling and learned recognition of unfamiliar predators. In this laboratory study, we tested the prediction that prior chemical exposure to a non-native predator feeding on conspecific tadpoles will subsequently allow tadpoles of the common toad (Bufo bufo) to recognize the chemical cues specifically released by this starved predator. Furthermore, we investigated the vulnerability of this chemically-mediated process to herbicide contamination. With these aims in view, groups of tadpoles were kept either unexposed or exposed for ten days to chemical cues from Turkish crayfish (Astacus leptodactylus) previously fed on tadpoles, both in uncontaminated water and in the presence of four sublethal concentrations of amitrole (0.01, 0.1, 1 and 10 mg.l⁻¹). We then assessed the effects of the six conditioning treatments on general activity and behavioural response to chemical cues from starved crayfish. Larval treatments did not affect the general activity of the tadpoles. By contrast, the treatments had significant effects on the behavioural response to the test solution prepared form starved crayfish. The only tadpoles to show an antipredator behavioural response to the chemical stimulation from starved crayfish belonged to the groups derived from chemical exposure to tadpole-fed crayfish in uncontaminated water and in contaminated water with the lowest concentration of amitrole (0.01 mg.l⁻¹). Conversely, this chemical stimulation produced no behavioural change in the control group or in the groups derived from exposure to tadpole-fed crayfish in contaminated water containing 0.1, 1 and 10 mg.l⁻¹ of amitrole. This study demonstrates that chemical cues released during the predator’s feeding activity can subsequently be used by common toad tadpoles in the recognition of an unfamiliar predator. In addition, our results show that the presence of sublethal amitrole concentrations can impair this recognition process. Such a pesticide effect might be especially detrimental for amphibian populations threatened by invasive predators.     

Diet-induced chemical phytomimesis by twig-like caterpillars of Biston robustum Butler (Lepidoptera: Geometridae)

Summary. Polyphagous caterpillars of the giant geometer Biston robustum resemble the twigs of their respective food sources in color and shape. Common predatory ants, including Lasius and Formica, were often observed to freely prowl directly on caterpillars bodies, even after antennal contact. This suggests that the cuticular chemicals of the caterpillars resemble those of the twigs of the foodplants, so we analyzed both by GC and GC-MS. The chemical compositions differed among caterpillars fed on a cherry, Prunus yedoensis, a chinquapin Castanopsis cuspidata, and a camellia Camellia japonica. The cuticular chemicals of the caterpillars resembled those of their corresponding food sources. When the caterpillar diets were switched from the cherry to camellia or chinquapin at the 4^th instars, the caterpillars cuticular chemicals changed after molting to resemble those of their respective foods. Caterpillars also changed their cuticular chemicals when they perched on cherry twigs and fed on camellia or chinquapin leaves, but not when they perched on camellia or chinquapin twigs and fed on cherry leaves. The chemical similarities between the caterpillars and the twigs were due to the digestion of host leaves, which indicates that this is a diet-induced adaptation.     

COD_(Cr)测定中排除氯离子干扰的进一步探讨

废水中化学需氧量的测定采用重铬酸钾法［１］,大多数情况下都存在Ｃｌ－干扰,其排除方法用ＨｇＳＯ４掩蔽,通过实验探讨不用剧毒药品ＨｇＳＯ４掩蔽Ｃｌ－的干扰,而用ＣＯＤＣｒ总量减去Ｃｌ－的量。实验结果表明：当测定化学需氧量较低而Ｃｌ－含量高的水样时,即使采用掩蔽Ｃｌ－也会产生较大的误差,而用测定值减去０．２２６［Ｃｌ－］之值更接近真值。     

氨法脱硫技术在化工企业燃煤锅炉中的应用

介绍了LS氨法喷雾烟气脱硫技术在云南解化集团有限公司的使用情况，针对化工企业实际情况和应用过程中出现的问题，提出改进措施和技术创新，使该项技术在应用中更加完善。