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21.
The volatiles released from several aphid and host plant species, alone or associated, were studied for their infochemical role in prey location. Using a four-arm olfactometer, the attraction of several combinations of three aphid (Myzus persicae, Acyrthosiphon pisum, and Brevicoryne brassicae) and three plant (Vicia faba, Brassica napus, and Sinapis alba) species toward Adalia bipunctata larvae and adults was observed. Both predatory larvae and adults were attracted only by A. pisum and M. persicae when they were crushed, whatever the host plant. (E)-beta-farnesene, the aphid alarm pheromone, was the effective kairomone for the ladybird. Plant leaves alone (V. faba, B. napus, and S. alba) or in association with nonstressed whole aphids (the three species) did not have any attraction for the predator. The B. brassicae specialist aphid is the only prey that was not attracted to A. bipunctata larvae and adults, even if they were crushed. Release of B. brassicae molecules similar to the host plant allelochemicals was demonstrated by GC-MS analysis. The lack of behavioral response of the ladybird at short distance toward the cruciferous specialist aphid was related only to the absence of (E)-beta-farnesene in the aphid prey volatile pattern. 相似文献
22.
A comprehensive survey has been carried out to establish which sun-screen agents are used by the cosmetics industry in Holland. During 1978, some 200 cosmetic sun preparations, composed of forty-eight brands, were purchased and analysed to determine which u.v. absorbing compounds were present. Most of those found were identified and quantified by means of thin layer chromatography and u.v. spectrometry. A basis for this work was the proposal by the European Cosmetic Manufacturers to produce a positive list of u.v. absorbers. It was felt that by carrying out this survey, some priority could be placed on the most popular materials used by the industry. When comparing those found with the European list of u.v. absorbers 1978, only twenty-four of the sixty compounds listed could be identified in the samples. The six most frequently used were found to be: <ul class="rlist hanging"> 1 2-Ethylhexyl.p.methoxycinnamate (nineteen brands). 2 2-Phenylbenzimidazole.5-sulphonic acid (eleven brands). 3 2-Ethoxyethyl.p.methoxycinnamate (nine brands). 4 3 (4′Methylbenzylidene)D,D,L-camphor (seven brands). 5 3-Benzylidene.D,L-camphor (six brands). 6 2-Hydroxy.4-methoxy.benzophenone (six brands). ul> Usage levels varied from 0.4% up to 6.8%. Twenty-two products used a combination of two, and four products a combination of three sun-screens. Les filtres u.v. dans les produits anti-solaires 1978 相似文献
23.
The distribution of neutrons produced by the reaction of 50MeV/u ^12C-ion on a thick Cu target are studied.The neutrons are measured with threshold activation detectors.Al.F,C,Al and In activation samples were used to measure neutrons with energy greater than 7,11,20,50MeV and thermal neutrons,respectively,The fluence rate,energy and angular distributions of neutrons,total neutron yield of 12C-ion and the emission rate in the forward direction of neutrons over 11 and 20MeV were obtained. 相似文献
24.
对荷兰诺瑞特超滤(UF)系统在深南电(中山)电力有限公司水处理设备中的运行特点和影响因素进行较系统、详细的阐述,总结了经济运行与维护应注意的问题。 相似文献
25.
26.
变频器的控制方式及选型应用 总被引:1,自引:0,他引:1
师红吉 《冶金设备管理与维修》2013,(3):60-63
对变频器的常用控制方式进行了比较,分析了各种控制方式的优缺点,为工程技术人员更好选择与使用变频器提供了借鉴和参考。 相似文献
27.
With the development of the health care industry, there has been growing recognition that e‐health implementation is needed to improve the efficiency, quality, and safety of care. In addition, a review of previous studies suggests that much can be learned by investigating the difference in national e‐health implementation in the United States and in South Korea. To this end, the main objective of this article is to compare the national e‐health implementation in the case of the United States and South Korea. The results show that in the United States a decentralized e‐health implementation is being followed by individual‐level e‐health. South Korea is pursuing ubiquitous health (u‐health) after a hospital information system and electronic health were implemented. The United States still lags behind many other countries in the implementation of e‐health, possibly due to its low uncertainty avoidance culture. South Korea has been among the frontrunner groups in e‐health implementation as a consequence of its highly developed telecommunication infrastructures and high uncertainty avoidance culture. On the basis of these results, we recommend that establishing health care policies be done on a national scale that takes into account the countries’ cultures. 相似文献
28.
Chenyang Fu Changjun Li Guihua Cui M. Ronnier Luo Robert W. G. Hunt Michael R. Pointer 《Color research and application》2012,37(4):238-254
Data were obtained for the colour appearance of unrelated colours under photopic and mesopic conditions. The effects of changes in luminance level and stimulus size were investigated. The method used was magnitude scaling of brightness, colourfulness, and hue. Two stimulus sizes (10° and 0.5°) and four starting luminance levels (60, 5, 1, and 0.1, cd/mup>2up>) were used. The results at 0.1 cd/mup>2up> had large variations, so data were obtained for two additional stimulus sizes (1° and 2°) at this luminance level. Ten observers judged 50 unrelated colours. A total of 17,820 estimations were made. The observations were carried out in a completely darkened room, after 20 min adaptation; each test colour was presented on its own. Brightness and colourfulness were found to decrease with decreases of both luminance level and stimulus size. The CAM97u model predicted brightness more accurately than CIECAM02 but gave worse performance in predicting colorfulness. For hue, CAM97u and CIECAM02 both gave satisfactory predictions. Using the brightness correlate from CAM97u, a new colour‐appearance model based on CIECAM02 was developed specifically for unrelated colours under photopic and mesopic conditions, with parameters to allow for the effects of luminance level and stimulus size. © 2011 Wiley Periodicals, Inc. Col Res Appl, 2011; 相似文献
29.
An experimental comparison of a graphite electrode and a gas diffusion electrode for the cathodic production of hydrogen peroxide 总被引:2,自引:0,他引:2
Anna Da?Pozzo Luca Di?Palma Carlo?Merli Elisabetta?PetrucciEmail author 《Journal of Applied Electrochemistry》2005,35(4):413-419
This work studies the production of hydrogen peroxide through the cathodic reduction of oxygen in acidic medium, by comparing the results obtained using a commercial graphite and a gas diffusion electrode. A low pH was required to allow the application of hydrogen peroxide generation to an electro-Fenton process. The influence of applied potential and the gas flow composition were investigated. The gas diffusion electrode demonstrates a higher selectivity for hydrogen peroxide production, without significantly compromising the iron regeneration, thus making its successful application to a cathodic Fenton-like treatment, possible. Unlike the graphite cathode, the gas diffusion cathode also proved to be effective in the air flow. 相似文献
30.
In this paper, instrumented impact test results obtained using V-notch and precracked Charpy specimens of AISI 308 weld and AISI 316 stainless steels are analysed for determining the plastic u24461280/xxlarge951.gif" alt="eegr" align="MIDDLE" BORDER="0">-factor for three-point bend specimens used in J-integral evaluation. Tested 316 stainless steel specimens were in various thermal aging/cold-work conditions whereas 308 weld specimens were in the as-welded condition. The results are analysed using the various procedures proposed in the literature and compared with experimental and finite element results reported in the literature. Based on our analysis, two polynomial expressions of a/W for u24461280/xxlarge951.gif" alt="eegr" align="MIDDLE" BORDER="0">ub>plub> are presented: one gives a sort of upper-bound in the a/W range 0.05–1.0 while the other gives conservative values (i.e., use of this results in J-R curves and J sufficiently conservative for engineering purposes). Both provide a smooth variation of u24461280/xxlarge951.gif" alt="eegr" align="MIDDLE" BORDER="0">ub>plub> over the entire a/W range unlike some of the expressions given in the literature which show a discontinuous change at an intermediate a/W. 相似文献