共查询到20条相似文献,搜索用时 15 毫秒
1.
Cook AF Shoemaker EM Smith BA Danielson GE Johnson TV Synnott SP 《Science (New York, N.Y.)》1981,211(4489):1419-1422
A quadruple long exposure of Io in eclipse exhibits faint auroral emission from the eruptive plumes. No luminous spots in the vents, predicted by Gold, were observed. Heat from the interior of Io appears to be the predominant source of energy in the plumes. 相似文献
2.
Yamaji A 《Science (New York, N.Y.)》1991,254(5028):89-91
The Jovian satellite Io has active volcanic hot spots. The point-to-point correlation of the hot-spot distribution indicates that the hot spots preferentially make chains. The arrangement of the chains is periodic with a typical spacing of 120 kilometers. The chains exhibit concordant trends with stresses imposed by the tidal deflection of the lithosphere, suggesting that the hot spots are formed along fissures in the lithosphere. The typical spacing may be controlled by lithosphere thickness. 相似文献
3.
Consolmagno GJ 《Science (New York, N.Y.)》1979,205(4404):397-398
Widespread volcanism on Jupiter's satellite Io, if it occurred over the age of the solar system, would quickly reduce the inventory of most common volatiles needed to drive such volcanism. One exception is the volatile element sulfur. It is therefore postulated that sulfur is the driving volatile for Ionian volcanism. Its presence is consistent with a carbonaceous-chondrite-like bulk composition for the original material that formed Io 4.5 billion years ago. The ubiquity of sulfur on Io today demonstrates the importance of this element in the processes that formed its surface. 相似文献
4.
Melting of io by tidal dissipation 总被引:1,自引:0,他引:1
The dissipation of tidal energy in Jupiter's satellite Io is likely to have melted a major fraction of the mass. Consequences of a largely molten interior may be evident in pictures of Io's surface returned by Voyager I. 相似文献
5.
Johnson TV Morrison D Matson DL Veeder GJ Brown RH Nelson RM 《Science (New York, N.Y.)》1984,226(4671):134-137
We report the first results of a program to determine the longitudinal distribution of volcanic activity on Jupiter's satellite Io. Infrared measurements at 8.7, 10, and 20 micrometers have been taken at a variety of orbital longitudes: strong variation in the 8.7- and 10-micrometer flux with longitude demonstrates that infrared emission arising from volcanic hotspots on Io is strongly concentrated in a few locations. Analysis of these data suggests that the active volcanic regions observed by the Voyager experimenters are still active, particularly the region around the feature known as Loki. Another source of flux, although of somewhat smaller magnitude, is indicated on the opposite hemisphere. If these sources are the only major volcanic centers on Io, then current global heat flow estimates must be revised downward. However, heat flow from as yet unobserved longitudes, hotspots at high latitudes, and conducted heat flow must still be measured. 相似文献
6.
Speckle observations of Jupiter's satellite Io at a wavelength of 5 micrometers during July 1984 resolved the disk and showed emission from a hot spot in the Loki region. The hot spot contributed a flux approximately equal to 60 percent of that from the disk. Images reconstructed by means of the Knox-Thompson algorithm showed the spot moving across the disk as the satellite rotated. It was located at 301 degrees +/- 6 degrees west longitude, 10 degrees +/- 6 degrees north latitude, and had a radiance of (2.96 +/- 0.54) x 10(22) ergs sec(-1) cm(-1) sr(-1)/A where A is the area of the spot. For an assumed temperature of 400 K, the area of the source would be 11,400 square kilometers. An active "lava lake" similar to that seen by Voyager may be the source of the infrared emission. 相似文献
7.
Several recent developments have implications for the neutral particle environment of Jupiter. Very hot sulfur ions have been detected in the Io torus with gyrospeeds comparable to the corotation speed, a phenomenon that would result from a neutral sulfur cloud. Current evidence supports the hypothesis that extensive neutral clouds of oxygen and sulfur exist in the Jupiter magnetosphere and that they are important sources of ions and energy for the Io torus. 相似文献
8.
为了解南蝠(Ia io)在维持稻田生态系统稳定性中的作用,采用粪便分析和直观法,研究了南蝠的捕食行为及其对稻田虫害发生的影响.结果表明:南蝠是控制农田害虫的有效天敌之一,在其捕食区域内稻田病虫害较轻,2~3 km半径区域水稻的平均产量比6~7 km半径区域增产98.2kg/667m2;南蝠的食物组成除鸟类外,还有鞘翅目、鳞翅目、半翅目、直翅目、膜翅目和蜱螨等昆虫/生物,多数种类昆虫均是水稻害虫或病害的传播者.南蝠在维护稻田生态系统稳定性和提高农作物产量方面具有重要的作用. 相似文献
9.
为了解南蝠(Ia io)在维持稻田生态系统稳定性中的作用,采用粪便分析和直观法,研究了南蝠的捕食行为及其对稻田虫害发生的影响。结果表明:南蝠是控制农田害虫的有效天敌之一,在其捕食区域内稻田病虫害较轻,2~3km半径区域水稻的平均产量比6~7km半径区域增产98.2kg/667m2;南蝠的食物组成除鸟类外,还有鞘翅目、鳞翅目、半翅目、直翅目、膜翅目和蜱螨等昆虫/生物,多数种类昆虫均是水稻害虫或病害的传播者。南蝠在维护稻田生态系统稳定性和提高农作物产量方面具有重要的作用。 相似文献
10.
The preliminary analysis of data from the Pioneer 10 S-band radio occultation experinment has revealed the presence of an ionosphere on the Jovian satellite Io (JI) having an electron density peak of about 6 x 10(4) electrons per cubic centimeter at an altitude of approximately 60 to 140 kilometers. This suggests the presence of an atmosphere having a surface number density of about 10(10) to 10(12) per cubic centimeter, corresponding to an atmospheric surface pressure of between 10(-8) and 10(-10) bar, at or below the detection threshold of the Beta Scorpii stellar occultation. A measurement of the atmosphere of Jupiter was obtained down to the level of about 80 millibars, indicating a large temperature increase at about the 20 millibar level, which cannot be explained by the absorption of solar radiation by methane alone and can possibly be due to absorption by particulate matter. 相似文献
11.
为缩短产品研制周期、增强企业竞争能力,逆向工程技术也正逐步从其他产品设计制造业领域引入到我国农业机械领域。以统收式采棉机的采摘部件梳齿为测绘对象,通过逆向工程技术,采用青岛雷顿数控设备有限公司生产的先进的NC(865)型三坐标测量仪进行扫描与测绘,获取了梳齿的点云数据,然后对其进行预处理、多边形阶段处理、参数化处理,最终运用SolidWorks软件绘制出三维模型,完成了梳齿部件的逆向设计。通过实例运用,证实了逆向工程技术在农业机械研究领域的可行性,其研究结果将对我国农业机械化的发展起到积极的推动作用。 相似文献
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14.
Stevenson DJ 《Science (New York, N.Y.)》1986,234(4779):1016-1017
15.
采用野外调查法对贵州飞龙洞南蝠的种群现状进行了研究。结果表明:2007~2011年,南蝠个体数量由2 000只减少到500只,性别比由1∶1.03增加到1∶1.27;南蝠的出生率呈逐年下降的态势,死亡率却呈逐年上升的态势。该研究可为南蝠的保护工作提供理论依据。 相似文献
16.
Many hypotheses have been postulated regarding the early evolution of the mammalian brain. Here, x-ray tomography of the Early Jurassic mammaliaforms Morganucodon and Hadrocodium sheds light on this history. We found that relative brain size expanded to mammalian levels, with enlarged olfactory bulbs, neocortex, olfactory (pyriform) cortex, and cerebellum, in two evolutionary pulses. The initial pulse was probably driven by increased resolution in olfaction and improvements in tactile sensitivity (from body hair) and neuromuscular coordination. A second pulse of olfactory enhancement then enlarged the brain to mammalian levels. The origin of crown Mammalia saw a third pulse of olfactory enhancement, with ossified ethmoid turbinals supporting an expansive olfactory epithelium in the nasal cavity, allowing full expression of a huge odorant receptor genome. 相似文献
17.
Hillis DM 《Science (New York, N.Y.)》2000,289(5486):1877-1878
18.
利用刺吸电位图谱(EPG)技术对亚洲柑橘木虱Diaphorina citri Kuwayama在寄主植物酸橙Citrus reticulata Blanco上的刺探取食行为进行了测定,获得柑橘木虱取食出现的波形,初步确定了取食波形与其行为之间的关系.结果表明,亚洲柑橘木虱在酸橙上产生8种主要的取食波形,依次为非刺探波(... 相似文献
19.
Eshleman VR Tyler GL Wood GE Lindal GF Anderson JD Levy GS Croft TA 《Science (New York, N.Y.)》1979,206(4421):959-962
Voyager 2 radio signals were observed essentially continuously during a grazing occultation of the spacecraft by the southern limb of Jupiter. Intensity data show a classic atmospheric occultation profile and the effects of turbulence and ionospheric focusing and defocusing. No reliable profile of the neutral atmosphere has yet been obtained, primarily because of a combination of large trajectory uncertainties and error multiplication effects associated with the grazing geometry of the Voyager 2 occultation. Analysis of the dispersive ionospheric refraction data yields preliminary profiles for the topside ionosphere at 66.7 degrees S (entry in the evening) and 50.1 degrees S (exit in the morning) that are reversed with respect to corresponding Voyager 1 profiles in terms of plasma concentration at a fixed altitude. Plasma scale heights and temperatures of 880 kilometers, 1200 K and 1040 kilometers, 1600 K were obtained for morning and evening conditions, respectively. Preliminary reduction of the pre-encounter occultation of Voyager 1 by the Io torus yields an average plasma density of about 1000 electrons per cubic centimeter. 相似文献
20.
Bada JL Fegley B Miller SL Lazcano A Cleaves HJ Hazen RM Chalmers J 《Science (New York, N.Y.)》2007,315(5814):937-9; author reply 937-9