Particle Track, X-ray, Thermal, and Mass Spectrometric Studies of Lunar Material     

Fleischer RL  Haines EL  Hanneman RE  Hart HR  Kasper JS  Lifshin E  Woods RT  Price PB 《Science (New York, N.Y.)》1970,167(3918):568-571

Particle tracks in Apollo 11 samples are dominantly of cosmic ray and solar origin: primary galactic and solar flare particles, likely spallation recoil tracks, and possible solar-wind heavy particles. The energy spectrum of irongroup nuclei is inferred from track density gradients in surface layers, and a limit of < 10(-7) centimeter per year is deduced for the surface erosion rate. From cosmic ray tracks in rock and core samples it is clear that the lunar soil is stirred often during each few million years. X-rays reveal augite, anorthite, olivine, ilmenite, troilite, nonmeteoritic iron, and assorted glasses, but no major structural damage. Hydrogen, helium, and other gases in the fines are compatible with expected solar wind ratios.  相似文献   

Polyteny: A Source of Cryptic Speciation among Copepods     

McLaren IA  Woods SM  Shea JR 《Science (New York, N.Y.)》1966,153(3744):1641-1642

A large form of the copepod Pseudocalanus is found in two warm, semi-landlocked fiords in arctic Canada, together with a similar but smaller form attributable to the widespread P. minutus. The large form has the same chromosomne number as P. minutus, but has larger chromosomes and a higher nuclear DNA content. There are suggestions in the literature that other similar polytenic and cryptic species occur among copepods.  相似文献   

Population nucleation, intensive agriculture, and environmental degradation: The Cahokia example     

William I. Woods 《Agriculture and Human Values》2004,21(2-3):255-261

Cahokia, the largest pre-European settlement in North America, was situated on the Middle Mississippi River floodplain and flourished for approximately three hundred years from the 10th century AD onward. The site was favorably located from an environmental standpoint, being proximal to a diversity of microhabitats including expanses of open water and marshes from which the essential, renewable fish protein could be procured. More importantly, the largest local zone of soils characterized as optimal for prehistoric hoe cultivation lay immediately to the east. Here, on the floodplain and along its bordering alluvial fans, the large maize outfields were situated, while the multi-crop house gardens were placed within the habitation zone on soils that had often been culturally enriched by prior occupation. As successful as this strategy might have been for small, dispersed populations in such a plentiful environment, nucleation of large numbers of people at Cahokia provided a different adaptive context that ultimately led to ruinous consequences. The seeds for the city's destruction centered anthropogenically produced environmental degradation. Demands on wood resources for fuel and construction were enormous and agricultural field clearance was in forested rather than prairie settings. The resultant watershed deforestation produced greatly increased rates of erosion, runoff, and unseasonable downstream flooding during the summer growing season. The economic and social consequences of declining production and localized crop failures proved disastrous for this city of farmers.  相似文献   

THE BIRTHPLACES OF LEADING AMERICANS AND THE QUESTION OF HEREDITY     

Woods FA 《Science (New York, N.Y.)》1909,30(757):17-21

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HISTORIOMETRY AS AN EXACT SCIENCE     

Woods FA 《Science (New York, N.Y.)》1911,33(850):568-574

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A mule cloned from fetal cells by nuclear transfer   总被引：1，自引：0，他引：1  

Woods GL  White KL  Vanderwall DK  Li GP  Aston KI  Bunch TD  Meerdo LN  Pate BJ 《Science (New York, N.Y.)》2003,301(5636):1063

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Magnetar-like emission from the young pulsar in Kes 75     

Gavriil FP  Gonzalez ME  Gotthelf EV  Kaspi VM  Livingstone MA  Woods PM 《Science (New York, N.Y.)》2008,319(5871):1802-1805

We report the detection of magnetar-like x-ray bursts from the young pulsar PSR J1846-0258, at the center of the supernova remnant Kes 75. This pulsar, long thought to be exclusively rotation-powered, has an inferred surface dipolar magnetic field of 4.9 x 10(13) gauss, which is higher than those of the vast majority of rotation-powered pulsars, but lower than those of the approximately 12 previously identified magnetars. The bursts were accompanied by a sudden flux increase and an unprecedented change in timing behavior. These phenomena lower the magnetic and rotational thresholds associated with magnetar-like behavior and suggest that in neutron stars there exists a continuum of magnetic activity that increases with inferred magnetic field strength.  相似文献   

酸度对胡敏酸与镉和锌离子络合反应的影响     

刘保峰  王强  孟威  魏世强 《西南大学学报》2005,27(4)

用离子交换平衡法研究了不同pH下胡敏酸与锌、镉单独及复合存在下形成络合物的稳定性及配位数.结果表明:在Zn2+,Cd2+单独存在时,络合反应的稳定常数及配位数随着pH值的增大而增大;相同pH条件下,Zn2+和胡敏酸络合物的稳定常数及配位数大于Cd2+.在Zn2+,Cd2+复合存在时,pH的变化与胡敏酸络合金属离子的稳定常数及配位数没有明显依存关系;与单独存在时相比,在pH 3.5和pH7.0时,Zn2+,Cd2+和胡敏酸络合物的稳定常数和配位数都减小;而在pH 5.0时,Cd2+和胡敏酸络合物的稳定常数和配位数都增大,Zn2+和胡敏酸络合物的稳定常数和配位数都减小.  相似文献   

Radiation-induced dechlorination of chloral hydrate and 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT)     

R J Woods  S Akhtar 《Journal of agricultural and food chemistry》1974,22(6):1132-1133

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蘑菇对流预冷的试验研究          下载免费PDF全文

何达  J.L.Woods  张魁学 《农业工程学报》1993,9(1):64-69

通过试验分析了在低温空气强制对流预冷过程中蘑菇传热、传质受气流速度、温度的影响。结果表明:对流预冷比真空预冷重量损失小、无冻伤。作者还用集总参数法建立了含有气化潜热的能量守恒传热微分方程,其数值解与试验吻合。改变参数可预测不同条件下蘑菇降温过程。  相似文献