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改革开放以来,我国橡胶工业的发展速度是前所未有的,其间有许多成功的经验,特别是入世后,在上世纪末全行业整体亏损的不利情况下,大家认识一致,认真对待,风雨同舟,趋利避害,经受住了考验,不仅行业经济全面复苏,而且取得新的发展。当前,全行业面对的是新一轮的竞争,而且更为激烈 相似文献
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《中华手工》2011,(12):60-61
两期"台湾工艺之旅"圆满结束。对于文化艺术,无论是走马观花还是深度阅读,各人经历不同感悟也会不一样。你心目中的台湾,是什么样子呢?8天的旅程,累,却幸福着。忘不了,太鲁阁天然大理石岩的鬼斧神工,忘不了,清晨日月潭散发的柔美光辉,忘不了,黄安福大师表演玻璃技艺洒下的滴滴汗珠,忘不了,粘碧华大师的艺术之家和她亲切的笑容,忘不了,汉声巷黄永松老师挥手作别时眼里的殷殷期盼,忘不了,台北世界设计展上将书法创意延伸的"妙法自然"忘不了,中华手工电台带给我们的欢声和笑语,忘不了……黄永松老师说,这一代人需要觉醒,但觉醒的方向不要错,要回到文化的母土。或许你已留意到, 相似文献
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尾矿干式堆存在磷矿山选矿厂中的应用 总被引:1,自引:0,他引:1
0 引言 尾矿设施具有保护环境,充分利用水资源和保护矿产资源的作用,是矿山生产不可缺少的设施,但投资巨大,基建投资占矿山总投资的10%以上,占选矿厂投资的20%左右,有的几乎与选矿厂的投资一样多,甚至超过选矿厂.尾矿设施的运行成本也较高,有些矿山尾矿设施运行成本占选矿厂生产成本的30%以上.近年来,由于征购土地和搬迁农户的费用越来越高,因此建设尾矿设施的费用也越来越高.此外,尾矿库还是矿山生产的最大的危险源之一,一旦尾矿库失事,将给工农业生产及下游人民生命财产造成巨大损失.而若采用干式堆存尾矿,则可较大地缓解以上矛盾,因干式堆存的尾矿只含有11%~15%的水分,且可依地形而堆存,大大减少了占地面积,且不易垮落.贵州某一选矿厂利用脱水设备实现了尾矿的干式堆存,情况介绍如下. 相似文献
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在我国陶瓷美术发展史上,凡有所成就,有所作为的陶瓷美术家,不论哪个时代,哪个艺术院派,都离不开继承传统,吸取精华,并通过自己的长期实践,不断创新,才形成自己独有的艺术风格.景德镇陶瓷美术家王步先生创作的青花作品,以其笔简意骇,博大精深,水色莹澈,淋漓尽致的风格,为人们所称赞.本文试就他的艺术风格归纳为三个方面来简略论述. 相似文献
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正入花甲之年的葛新华,20年默默收藏3000多把老算盘,为的是让人们在被键盘和鼠标声占满的今天,还能记得算珠拨动的旋律。"打主意,秋千格。"打一物品是什么?在没有计算器和电脑的年岁,这个几乎存在每家每户的老物件,如今已经慢慢淡出了人们的视野。曾几何时,珠算课是小学里必修的课程,儿时背着算盘上学堂,算珠在背后摇得"噼里啪啦"响;账房里的老先生记账算数,加减乘除,样样离不开打算盘。然而,当算盘逐渐远去时,有一个人,仍然守护着算盘拨动的记忆,经历长长20个年头,默默收集3000多把老算盘,他最欣慰的,是成立了自己独具特色的家庭式收藏馆,他就是葛新华。这位热爱算盘如痴,喜爱"精打细算"的老者年纪60岁,在他的收藏馆里,可以看到琳琅满目的算盘世界。墙上歪歪斜斜不规则地挂着许多算盘, 相似文献
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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
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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
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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
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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
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L. P. Brower J. N. Seiber C. J. Nelson S. P. Lynch M. M. Holland 《Journal of chemical ecology》1984,10(4):601-639
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
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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
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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
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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
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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
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Single-choice and three-choice tests were used to determine the relative importance of host-plant chemical extracts in eliciting feeding by spruce bud worm larvae. Water-soluble components of the host trees are the most important and, of these, the sugar and glycoside fractions are the most stimulating. The amino acid and organic base fractions have no apparent effect. The organic acid fractions deter feeding slightly.Lepidoptera: Tortricidae.Supported by the National Sciences and Engineering Research Council of Canada, Operating Grant No. A9723 to P.J.A. 相似文献
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Dan Rittschof 《Journal of chemical ecology》1980,6(1):103-118
Simulated gastropod predation sites were observed in the gulf intertidal near the Edward Ball Marine Laboratory, Sopchoppy, Florida,Fundulus similis, Callinectes sapidus, Melongena corona, Clibanarius vittatus, andPagurus longicarpus were attracted to the sites by small molecules released passively from the flesh of wounded or dead animals. Flesh consumers (F. similis, C. sapidus, andM. corona) were attracted to molecules released from the flesh of bivalves, gastropods, and crabs. Shell users (C. vittatus andP. longicarpus) were attracted only to small molecules from gastropod flesh, withP. longicarpus attendingP. duplicatas sites whileC. vittatus preferentially attendedM. corona, Busycon contrarium, andBusycon spiratum sites. Flesh consumers and shell users may be attracted to the sites by different sets of small molecules. The addition of proteolytic enzymes to the flesh increased the attendants at a site, indicating that the attractant molecules might be amino acids or small peptides. Flesh consumers were attracted to the sites primarily in the first 12 hr while the shell users were attracted from 2 hr to several days postinitiation. New shells were attractive to hermit crabs up to 12 hr after entry by a hermit crab. The shell species of the attendantC. vittatus were in different proportions than the generalC. vittatus population, and the shell fit of theP. longicarpus attendants was not as good as the general population ofP. longicarpus. Significantly moreC. vittatus attended than P. longicarpus, and it was speculated that there were moreC. vittatus in the area with a poor shell fit thanP. longicarpus. 相似文献
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Aggregations of the common silverfish, Lepisma saccharina, and giant silverfish, Ctenolepisma longicaudata (both Thysanura: Lepismatidae), are mediated by species-specific pheromones. In dual-choice, still-air olfactometer experiments,
filter paper previously exposed to 12 male, female, or juvenile L. saccharina or C. longicaudata arrested conspecifics regardless of developmental stage or sex. Arrestment responses required physical contact with the pheromone.
Insect-derived frass, scales, antennae, and setae, as well as salivary gland content, are not the source of the contact pheromone
in L. saccharina. Lepisma saccharina did not respond to the pheromone of C. longicaudata, nor to that of another thysanuran, the firebrat Thermobia domestica. However, C. longicaudata responded to pheromones of both L. saccharina and T. domestica, whereas T. domestica responded to the C. longicaudata but not L. saccharina pheromone. These results support the hypothesis that a closer phylogenetic relationship exists between C. longicaudata and T. domestica than between C. longicaudata and L. saccharina, but a definitive conclusion must await molecular genetic analyses of all three species. 相似文献