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1.
综述了国内外异丁烷脱氢制备异丁烯工艺的研究进展,包括FBD-4工艺、Oleflex工艺、Catofin工艺、Star工艺、Linde工艺和ADHO工艺等,提出了未来发展的建议。  相似文献   

2.
综述了目前世界上丙烷催化脱氢制丙烯的工艺及其迚展,主要包括Oleflex工艺、Catofin工艺、STAR工艺、PDH工艺和FBD工艺。对比了这五种常用工艺方法的基本特点,描述了国内丙烷脱氢制丙烯项目的开工及产能情况,介绍了各种工艺的基本情况,幵对相兲的催化剂迚行了简述。在此基础上,对丙烷催化脱氢制丙烯工艺和相兲催化剂迚行了展望。  相似文献   

3.
本文介绍了合成N-苯基-2,6-二氯苯胺的三条工艺路线,对各条工艺路线的优缺点进行比较,从而确定了最佳合成工艺路线并对该工艺路线进行了合成工艺研究,提出了最佳工艺条件,为工业化生产提供了指导依据。  相似文献   

4.
同步生物脱氮除磷工艺的研究进展   总被引:1,自引:0,他引:1  
钟四姣 《广东化工》2007,34(7):99-102
本文分析了传统同步生物脱氮除磷工艺存在的问题,介绍了一些传统工艺的改进工艺和几种新工艺,包括A2/O工艺,改进的A2/O工艺,改进的SBR工艺及其他一些工艺,阐述了他们的特点,并探讨了同步生物脱氮除磷工艺的发展趋势。  相似文献   

5.
二甲基二氯硅烷水解工艺研究进展   总被引:1,自引:0,他引:1  
综述了二甲基二氯硅烷水解工艺的研究进展,包括恒沸酸水解工艺、饱和酸水解工艺和浓酸水解工艺.着重介绍了各种水解工艺在氯化氢回收利用上的改进,通过对各水解工艺优缺点的探讨,展望了二甲基二氯硅烷水解工艺的发展方向.  相似文献   

6.
为选定华亭FMTP项目配套污水处理工艺,实现投产后污水处理的达标排放,分析了污水预处理工艺、A2/O工艺、SBR工艺、MBBR工艺和BAF工艺的原理及各工艺的优缺点,结合华亭FMTP项目的实际情况和废水指标,预处理工艺选择混凝沉淀和气浮工艺,废水处理工艺选择了SBR和MBBR两级串联的处理工艺。  相似文献   

7.
《煤化工》2017,(2)
介绍了国内外3种类型的煤热解技术,其中:气体热载体工艺包括美国的COED工艺、LFC工艺、日本的粉煤快速热解工艺、ECOPRO工艺、我国的MRF工艺和内构件移动床热解工艺等;固体热载体工艺包括美国的Toscoal工艺、德国的LR工艺、前苏联的ETCH-175工艺和大连理工大学开发的DG工艺等;无热载体工艺即神雾科技集团股份有限公司开发的无热载体蓄热式旋转床热解工艺。主要从工艺流程、技术特点、工业化应用等方面,对这些工艺进行了分析,并指出了煤热解技术的发展趋势。  相似文献   

8.
介绍了液氯热水汽化工艺及蒸气汽化工艺,从工艺复杂性、经济性、可操作性及安全性等方面对两种汽化工艺进行了分析比较,得出了蒸气汽化工艺优于热水汽化工艺的结论。  相似文献   

9.
综述了氯乙烯合成工艺的最新研究进展,讨论了不同工艺以及催化剂的优缺点。将无汞工艺与目前国内比较成熟的含汞工艺进行了比较,指出了无汞工艺法是国内未来氯乙烯合成工艺的发展趋势。  相似文献   

10.
Canon工艺研究进展   总被引:3,自引:0,他引:3  
阐述了Canon工艺的生物化学和微生物学原理,分析了该工艺的技术特征和工艺效能,讨论了温度、pH、氨氮浓度、溶解氧浓度等因素对工艺效能的影响,介绍了Canon工艺的研究和应用现状,指出了该工艺的现存问题及研究方向。  相似文献   

11.
Olfactory-mediated behavioral interactions were investigated among the five scolytid species comprising the southern pine bark beetle group. Behavioral response, as determined from field trap catch data, showed that each species was attracted in greatest numbers to the pheromonal blend produced by conspecifies. Interspecifically,D. frontalis displayed no cross-attractancy toIps pheromonal blends, but was weakly attracted to the pheromonal blend of femaleD. terebrans. ThreeIps species displayed varying degrees of cross-attraction as well as to theDendroctonus pheromonal blends. More specifically,I. calligraphus was attracted toI. avulsus and, to a very limited extent, also to the maleD. terebrans pheromonal blend.I. avulsus was somewhat more cross-attractive thanI. calligraphus and showed attraction to the pheromonal blends of femaleD. frontalis, male and femaleD. terebrans, maleI. calligraphus, and maleI. grandicollis. I. grandicollis showed the greatest degree of cross-attraction, particularly in response to theDendroctonus pheromonal blends.Research support in part by CSRS grant 86-CRCR-1-2270, NATO grant CRG.0710/86 and Texas Agricultural Experiment Station project MS1525 (while M.T.S. and T.L.P. were with Texas A&M University). The findings, opinions, and recommendations expressed herein are those of the authors and not necessarily those of the U.S. Department of Agriculture.  相似文献   

12.
The effect of aphid population size on host-plant chemical defense expression and the effect of plant defense on aphid population dynamics were investigated in a milkweed-specialist herbivore system. Density effects of the aposematic oleander aphid, Aphis nerii, on cardenolide expression were measured in two milkweed species, Asclepias curassavica and A. incarnata. These plants vary in constitutive chemical investment with high mean cardenolide concentration in A. curassavica and low to zero in A. incarnata. The second objective was to determine whether cardenolide expression in these two host plants impacts mean A. nerii colony biomass (mg) and density. Cardenolide concentration (microgram/g) of A. curassavica in both aphid-treated leaves and opposite, herbivore-free leaves decreased initially in comparison with aphid-free controls, and then increased significantly with A. nerii density. Thus, A. curassavica responds to aphid herbivory initially with density-dependent phytochemical reduction, followed by induction of cardenolides to concentrations above aphid-free controls. In addition, mean cardenolide concentration of aphid-treated leaves was significantly higher than that of opposite, herbivore-free leaves. Therefore, A. curassavica induction is strongest in herbivore-damage tissue. Conversely, A. incarnata exhibited no such chemical response to aphid herbivory. Furthermore, neither host plant responded chemically to herbivore feeding duration time (days) or to the interaction between herbivore initial density and feeding duration time. There were also no significant differences in mean colony biomass or population density of A. nerii reared on high cardenolide (A. curassavica) and low cardenolide (A. incarnata) hosts.  相似文献   

13.
Three species ofIps pine bark beetles in Hopping's group IX (S.L. Wood'sgrandicollis group),Ips confusus, I. lecontei, andI. paraconfusus, are parapatrically distributed in the American Southwest. They share post-Pleistocene altitudinal ecotones with their host pines. Adjacent to these areas of host overlap, we tested the hypothesis that aggregation pheromones produced by male beetles and/or host volatiles are sufficient to elicit the speciesspecific colonization behaviors typical of these threeIps species in nature. A more distantly related species,I. pini (Hopping's group IV, S.L. Wood'spini group) was used for outgroup comparison. Under the influence of pheromone, males ofI. confusus andI. paraconfusus do not discern among unin-fested log bolts of host and nonhost pine prior to bark contact. Males responding to pheromones emanating from infested bolts are similarly undiscriminating. Females ofI. confusus andI. lecontei olfactorily discern the combination of conspecific males in host pine from other possible beetlepine combinations; females ofI. paraconfusus do not. FemaleI. pini discerned conspecific pheromone from that ofI. lecontei. The bark beetle predator,Enoclerus lecontei, is attracted by, but does not discriminate among, the male-produced volatiles of these Group IXIps species. These results support a hypothesis that divergence in pheromonal responses by these group IXIps species has evolved following their speciation, having been manifested first in the female sex. Evolutionarily, the derived pheromonal messages have preceded their behavioral discrimination by these beetles. Additional speciesspecific cues may operate between the sexes in the field that may preclude heterospecific pairings.  相似文献   

14.
Females of severalAttagenus species demonstrated calling behaviors similar to those previously reported forA. elongatulus. Attagenus rufipennis females did not call until they were 12–14 days old. OtherAttagenus species called at approx. 4 days of age. All species exhibited diurnal periods of calling activity. Interspecific pheromone responses were tested, withA. megatoma megatoma, A. megatoma canadensis, A. megatoma japonicus, andA. schaefferi spurcus showing equal cross-responses. Male response to females was demonstrated inA. rufipennis andA. bicolor. Attagenus rufipennis, bicolor, andelongatulus males responded only to female extracts of their own species.Mention of a proprietary product does not constitute an endorsement by the USDA.  相似文献   

15.
Allelopathic interactions among algae   总被引:1,自引:0,他引:1  
Five species of green algae isolated from the Cleveland County, Oklahoma, area and a commercially obtained yellow-green alga were tested for allelopathic interactions. Axenic cultures ofPandorina morum Bory were stimulated in three sterile filtrates from nonaxenic cultures ofScenedesmus incrassatulus var.mononae G.M. Smith, with the oldest filtrate showing the least stimulation. By measuring the growth of axenic cultures inoculated into sterile filtrates of old cultures, instances of inhibition and stimulation were recorded in three screening experiments.Cosmarium vexatum West filtrate was inhibitory to the five other species, a characteristic probably important in its role of producing waterblooms in ponds and swamps. The allelopathic effects of filtrates of the five other species onBolrydium becherianum Vischer could be a key to its restriction to terrestrial sites. Instances of heat lability of the active substances were noted. These interactions, both allelopathic and stimulatory, probably play a significant role in the succession of algal blooms in nature.  相似文献   

16.
国外生物降解聚合物的种类及主要组分   总被引:3,自引:0,他引:3  
据1996~1998年国外有关文献的汇集,由美,日,德等国主要研制,生产的生物降解聚合物种类为:1,单一型生物降解聚合物;(1)合成酯(酸)类;(2)淀粉基材料;(3)天然高分子材料;2、复合型生物降解聚合物;(1)不同种类的烃基互聚物;(2)烃酯(酸)/聚酯(3)脂肪族聚酯/芳香族聚酯共聚物;(3)淀粉基复合型,(5)光/生物降解聚合物;3、可生物降解水溶性聚合物。  相似文献   

17.
The pattern of variation in gross cardenolide concentration of 111Asclepias speciosa plants collected in six different areas of California is a positively skewed distribution which ranges from 19 to 344 g of cardenolide per 0.1 g dry weight with a mean of 90 g per 0.1 g. Butterflies reared individually on these plants in their native habitats ranged from 41 to 547 g of cardenolide per 0.1 g dry weight with a mean of 179 g. Total cardenolide per butterfly ranged from 54 to 1279 g with a mean of 319 g. Differences in concentrations and total cardenolide contents in the butterflies from the six geographic areas appeared minor, and there were no differences between the males and the females, although the males did weigh significantly more than females. The uptake of cardenolide by the butterflies was found to be a logarithmic function of the plant concentration. This results in regulation: larvae which feed on low-concentration plants produce butterflies with increased cardenolide concentrations relative to those of the plants, and those which feed on high-concentration plants produce butterflies with decreased concentrations. No evidence was adduced that high concentrations of cardenolides in the plants affected the fitness of the butterflies. The mean emetic potencies of the powdered plant and butterfly material were 5.62 and 5.25 blue jay emetic dose fifty units per milligram of cardenolide and the number of ED50 units per butterfly ranged from 0.28 to 6.7 with a mean of 1.67. Monarchs reared onA. speciosa, on average, are only about one tenth as emetic as those reared onA. eriocarpa. UnlikeA. eriocarpa which is limited to California,A. speciosa ranges from California to the Great Plains and is replaced eastwards byA. syriaca L. These two latter milkweed species appear to have a similar array of chemically identical cardenolides, and therefore both must produce butterflies of relatively low emetic potency to birds, with important ecological implications. About 80% of the lower emetic potency of monarchs reared on A. speciosa compared to those reared onA. eriocarpa appears attributable to the higher polarity of the cardenolides inA. speciosa. Thin-layer Chromatographie separation of the cardenolides in two different solvent systems showed that there are 23 cardenolides in theA. speciosa plants of which 20 are stored by the butterflies. There were no differences in the cardenolide spot patterns due either to geographic origin or the sex of the butterflies. As when reared onA. eriocarpa, the butterflies did not store the plant cardenolides withR f values greater than digitoxigenin. However, metabolic transformation of the cardenolides by the larvae appeared minor in comparison to when they were reared onA. eriocarpa. AlthoughA. eriocarpa andA. speciosa contain similar numbers of cardenolides and both contain desglucosyrioside, the cardenolides ofA. speciosa overall are more polar. ThusA. speciosa has no or only small amounts of the nonpolar labriformin and labriformidin, whereas both occur in high concentrations inA. eriocarpa. A. speciosa plants and butterflies also contain uzarigen, syriogenin, and possibly other polar cardenolides withR f values lower than digitoxin. The cardenolide concentration in the leaves is not only considerably less than inA. eriocarpa, but the latex has little to immeasurable cardenolide, whereas that ofA. eriocarpa has very high concentrations of several cardenolides. Quantitative analysis ofR f values of the cardenolide spots, their intensities, and their probabilities of occurrence in the chloroform-methanol-formamide TLC system produced a cardenolide fingerprint pattern very different from that previously established for monarchs reared onA. eriocarpa. This dispels recently published skepticism about the predictibility of chemical fingerprints based upon ingested secondary plant chemicals.Lepidoptera: Danaidae.Apocynales: Asclepiadaceae.This study was supported by U.S. National Science Foundation grants DEB 75-14265 and 78-10658 to Amherst College and BSR-8119382 to the University of Florida with L.P. Brower as Principal Investigator and DEB75-14266, DEB78-15419, and DEB-81-19391 to the University of California at Davis with J.N. Seiber as Principal Investigator.  相似文献   

18.
DMC (Dynamic Matrix Control) has been used successfully in industry for the last decade. It can deal with constraints and unusual dynamic behavior directly. It also shows a good control performance for the servo problem. Relatively, it can’t reject disturbances systematically. We propose a modified DMC method to control the regulatory process more efficiently. The proposed DMC method makes the control output by subtracting the estimated disturbance from the control output of the original DMC. Here, the disturbance is estimated by a new disturbance estimator. It shows better control performances than the original DMC.  相似文献   

19.
The degree of soil mining by agricultural production in Southern Mali is assessed by calculating nutrient balances: differences between the amount of plant nutrients exported from the cultivated fields, and those added to the fields. Export processes include extraction by crops, losses due to leaching, to erosion, and to volatilization and denitrification. Inputs include applications of fertilizer and manure, restitution of crop residues, nitrogen fixation, atmospheric deposition of nutrients in rain and dust, and enrichment by weathering of soil minerals. Nutrient balances are calculated for N, P, K, Ca, and Mg. Both pessimistic and optimistic estimates are given.The resulting figures indicate, even when the most optimistic estimates are used, large deficits for nitrogen, potassium and magnesium. For the region as a whole, the calculated deficits are -25 kg N/ha,-20 kg K/ha, and -5 kg Mg/ha. Further, acidification is to be expected, in particular in areas where cotton is grown. The deficits are caused by traditional cereal crops, but also by cotton and especially by groundnut. The latter two crops are fertilized, but insufficiently. It is important to note, that the negative figures are not automatic recommendations for application of a specific amount of additional fertilizer. For phosphorus and calcium the balance of the region as a whole appears to be about in equilibrium, but locally large variations may occur.Erosion and denitrification are important causes of nutrient loss, accounting respectively for 17 and 22% of total nitrogen exports. Atmospheric deposition and weathering of minerals in the soil are still important nutrient inputs that contribute as much as nutrients as organic and mineral fertilizer combined. Nutrient depletion is very large in comparison to the amount of fertilizer applied. Drastic options, such as doubling the application of fertilizer or manure, or halving erosion losses, even if feasible, would still not be enough to make up for the calculated deficits.The annual value of withdrawn nutrients, if related to prices of fertilizers, varies between 10,000 and 15,000 FCFA/ha (40-60 US $/ha). Since the estimated average gross margin from farming in this area is 34,000 FCFA/ha (123 US $/ha), soil mining appears to provide an amount equal to 40% of farmers' total income from agricultural activities.  相似文献   

20.
Inorganic/organic hybrid materials have considerable promise and are beginning to become a major area of research for many coating usages, including abrasion and corrosion resistance. Our primary approach is to prepare the inorganic phase in situ within the film formation process of the organic phase. The inorganic phase is introduced via sol-gel chemistry into a thermosetting organic phase. By this method, the size, periodicity, spatial positioning, and density of the inorganic phase can be controlled. An important aspect of the inorganic/organic hybrid materials is the coupling agent. The initial task of the coupling agent is to provide uniform mixing of the oligomeric organic phase with the sol-gel precursors, which are otherwise immiscible. UV-curable inorganic/organic hybrid systems have the advantages of a rapid cure and the ability to be used on heat sensitive substrates such as molded plastics. Also, it is possible to have better control of the growth of the inorganic phase using UV curing. It is our ultimate goal to completely separate the curing of inorganic and organic phases to gain complete control over the morphology, and hence optimization of “all” the coating properties. Thus far, it has been found that concomitant UV curing of the inorganic and organic phases using titanium sol-gel precursors afforded nanocomposite coatings which completely block the substrate from UV light while maintaining a transparent to visible light. Also, it has been found that the morphology of the inorganic phase is highly dependent on the concentration and reactivity of the coupling agent. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago, IL.  相似文献   

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