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291.
自1960年第一台激光器问世以来的近50年中,激光光谱学一直是研究领域的重点,并且在科学、医药以及技术的许多方面取得显著进展,得到越来越多的应用。 相似文献
292.
彩色油墨的填充与封装工艺是电润湿显示制造技术的核心,如何提高填充均匀性和制程效率仍然是电润湿显示技术量产的关键挑战之一。本文提出一种基于相变操控的电润湿显示油墨创新填充和封装方法,即在空气环境中完成油墨液相填充,经低温凝固后投入液体环境完成封装。该方法有效规避了在传统液下环境中填充涉及的油/水/固三相界面操控的复杂性,提高了填充工艺的兼容性和稳定性。对油墨厚度的分析结果表明,基于相变操控填充油墨厚度与像素墙高度的相关性更好,较传统自组装填充具有更好的膜厚控制性。相变操控填充电润湿显示器件的光电响应处于合理水平。本研究有效解决了电润湿显示油墨填充的技术瓶颈,对推进电润湿显示技术的应用具有重要意义。 相似文献
293.
Aurelio Ramírez Bautista Adrian Leyte-Manrique Jonathon C. Marshall Geoffrey R. Smith 《西北部美国博物学家》2011,71(2)
We examined the effect of elevation on litter-size variation in viviparous lizards of the Sceloporus grammicus complex in 10 states of Mexico. Female snout–vent length (SVL) decreased with increasing elevation, and absolute litter size based on embryos also tended to de crease with increasing elevation. However, after controlling for variation in female body size, we found that litter sizes tended to be relatively larger at higher elevation. Elevation therefore appears to influence litter size in these lizards; however, relatively little of the variation is explained by elevation; thus, other factors are likely making substantial contributions to the observed litter-size variation. The S. grammicus complex appears to be a good model system for examining the underlying causes of geographic and elevational variation in lizard life histories. Examinamos el efecto del altitud en la variación del tamaño de camada de las lagartijas vivíparas del complejo Sceloporus grammicus en 10 estados de México. La LHC de las hembras disminuyó con la altitud, y el tamaño absoluto de camada, calculado con base en el número de embriones, también tendió a disminuir. No obstante, después de controlar la variación en el tamaño corporal de las hembras, encontramos que los tamaños de camada tendieron a ser relativamente más grandes en altitudes mayores. La altitud, por tanto, parece influir en el tamaño de camada de estas lagartijas; sin embargo, la altitud explica relativamente poco de la variación, por lo que, es probable que otros factores contribuyan substancialmente a la variación observada en el tamaño de camada. El complejo S. grammicus parece ser un buen sistema para estudiar las causas fundamentales de la variación geográfica y altitudinal en la historia de vida de las lagartijas. 相似文献
294.
Angela M. Ortega-León Maricela Villagrán-Santa Cruz J. Jamie Zú?iga-Vega Raúl Cueva-del Castillo Fausto R. Méndez-de la Cruz 《西北部美国博物学家》2011,69(1)
Asynchronous reproduction is a common phenomenon in high-elevation populations of lizards from Central México. Sperm storage in the reproductive tract of females is the mechanism for making oocyte fertilization possible. Our study addresses questions related to functional oviductal sperm storage of females mating on different dates throughout the reproductive season. A population of Sceloporus mucronatus with copulation in the summer and ovulation in the fall was chosen for this experiment. Eleven females that copulated in the field during June and 13 females that copulated in captivity during August were maintained in the laboratory until parturition. The number of pregnant females and the litter sizes produced in each experimental group were indicative of the viability of the stored sperm. Sperm stored in the reproductive tract of females were able to fertilize eggs after 4 months. No significant differences were found in the number of pregnant females between the 2 experimental groups nor in the litter sizes that they produced. We found that the amount of time sperm were held in the female reproductive tract (ca. 3 months) had no effect on the capacity of sperm to fertilize eggs. Histological examination of 8 oviducts collected before the mating season eliminated the possibility of sperm storage from one year to the next. In this system, sperm retention could have evolved as a response mechanism to deal with the asynchrony between sexes in the reproductive cycles. However, we cannot rule out alternative hypotheses. 相似文献
295.
We examined attributes of pi?on pine ( Pinus edulis ) associated with the probability of infestation by pi?on ips ( Ips confuses ) in an outbreak in the Coconino National Forest, Arizona. We used data collected from 87 plots, 59 infested and 28 uninfested, and a logistic regression approach to estimate the probability of infestation based on plot and tree-level attributes. Pi?on pine stand density index was a good predictor of the likelihood of infestation by pi?on ips at the plot level, and a cross-validation analysis confirmed that the model correctly classified 82% of the cases. Diameter at root collar and pi?on dwarf mistletoe infestation level were good predictors of individual tree infestation, and a cross-validation analysis indicated that the model correctly classified 72% of the cases. Results suggest that the occurrence of pi?on ips infestations may be related to stress factors associated with increased stocking and pi?on dwarf mistletoe infestations. 相似文献
296.
对墨西哥湾北部水深约540 m的上陆坡GC185区(GC-F样品)和水深约2200 m的下陆坡AC645区(AC-E样品)冷泉碳酸盐岩中的脂肪酸及其单体化合物的δ13C进行了分析. 在AC-E和GC-F冷泉碳酸盐岩样品中检测到了30多种脂肪酸化合物, 均以主峰碳为C16的低碳数(<C20)脂肪酸为主, 具偶碳优势, 主要包括正构脂肪酸、异构(i-)/反异构(ai-)脂肪酸以及带支链的(iso/anteiso)奇碳数脂肪酸. 其中n-C12:0, n-C13:0, i-C14:0和n-C14:0具有明显偏低的δ13C值(39.99‰~32.36‰), 可能来源于冷泉生物. n-C18:2和C18:1△9具有相同的碳同位素值, 可能来源于冷泉渗漏区贝氏硫细菌属/辫硫菌属. 支链奇碳数脂肪酸(iso/anteiso-C13~C17)具有特别负的δ13C值(63.95‰~44.17‰), 明显不同于其他类别脂肪酸的碳同位素值, 推断这类化合物是海底渗漏区甲烷厌氧氧化过程中的硫酸盐还原细菌生命活动的产物. 相似文献
297.
Radon-Nikodym theorem in signed Loeb space 总被引:1,自引:0,他引:1
MA Chunhui LI Shenggang SHI Yanwei . College of Mathematics Information Science Shaanxi Normal University Xi’an Shaanxi China . School of Science Xi’an Architecture Technology University Xi’an . Department of Basic Courses Xi’an Peihua University Xi’an 《武汉大学学报:自然科学英文版》2010,15(1):21-24
This paper gives the Radon-Nikodym theorem in signed Loeb space under 1-saturated nonstandard model. First,the nonstandard characterization of absolute continuity is discussed,on which Radon-Nikodym theorem in signed Loeb space is obtained. Then,some facts about a finite signed Loeb measure and its variation are shown. 相似文献
298.
The effect of Si on the austenite stabilization, martensite morphology, and magnetic properties in Fe-26%Ni-x%Si (x=3.5, 5, and 6) alloys have been studied by means of transmission electron microscopy (TEM) and M?ssbauer spectroscopy techniques. TEM observations reveal that the martensite morphology is closely dependent on the Si content. The volume fraction changes of martensite and austenite phases, the hyperfine magnetic field, and isomer shift values have been determined by Mssbauer spectroscopy. The M?ssbauer study reveals that the hyperfine magnetic field, the isomer shift values and the volume fraction of martensite decrease with increasing Si content. 相似文献
299.
LIU Yu * CAI QiuFang SONG HuiMing AN ZhiSheng & Hans W. LINDERHOLM The State Key Laboratory of Loess Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi’an China Department of Environmental Science Technology School of Human Settlements Civil Engineering Xi’an Jiaotong University Xi’an Graduate University of Chinese Academy of Sciences Beijing Regional Climate Group Department of Earth Sciences... 《科学通报(英文版)》2011,(Z2):2986-2994
Amplitudes, rates, periodicities, causes and future trends of temperature variations based on tree rings for the past 2485 years on the central-eastern Tibetan Plateau were analyzed. The results showed that extreme climatic events on the Plateau, such as the Medieval Warm Period, Little Ice Age and 20th Century Warming appeared synchronously with those in other places worldwide. The largest amplitude and rate of temperature change occurred during the Eastern Jin Event (343-425 AD), and not in the late 20th century. There were significant cycles of 1324 a, 800 a, 199 a, 110 a and 2-3 a in the 2485-year temperature series. The 1324 a, 800 a, 199 a and 110 a cycles are associated with solar activity, which greatly affects the Earth surface temperature. The long-term trends (>1000 a) of temperature were controlled by the millennium-scale cycle, and amplitudes were dominated by multi-century cycles. Moreover, cold intervals corresponded to sunspot minimums. The prediction indicated that the temperature will decrease in the future until to 2068 AD and then increase again. 相似文献
300.
Our world has been changing at an exponential rate.As a result of this rapid growth,we will be forced to make changes in not only the way we live in the environment but also in the environment itself such as designing the cities of the future to be in greater harmony with the increasing population and growing complexity.The paper contains both reflections on global awareness and comprehensive criteria and their priorities for choosing the most desirable city. 相似文献