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121.
Chen DY Stern SA Garcia-Osta A Saunier-Rebori B Pollonini G Bambah-Mukku D Blitzer RD Alberini CM 《Nature》2011,469(7331):491-497
122.
蔡琴 《四川大学学报(自然科学版)》2017,54(1):76-80
针对机器人避障轨迹控制过程中存在的路径优化以及如何躲避大障碍物或者是多障碍物的情况,本文提出一种基于狄克斯特拉算法与贝塞尔曲线的机器人移动避障实时控制改进算法,该算法引入机器人与目标终点路径的速度分量,采用狄克斯特拉算法进行移动轨迹路径优化,进而采用贝赛尔曲线修订优化路径,以此满足动态约束条件.仿真结果表明:相对于改进人工势场算法,本文构建的改进算法使得机器人移动时间缩短,机器人避障运动规划明显改善,具有较强的鲁棒性. 相似文献
123.
CHEN Hua QIU ZhiLi LU TaiJin STERN Richard STACHEL Thomas SUN Yuan ZHANG Jian KE Jie PENG ShuYi QIN SheCai 《科学通报(英文版)》2013,58(1):99-107
The components and evolution of subcontinental lithospheric mantle beneath the North China Craton and the Yangtze Craton is a current topic in the geological study of China and the carbon isotopic composition of diamond is one of the most direct probes into cratonic lithospheric mantle processes.In this paper,in-situ SIMS(Secondary Ion Mass Spectrometry) techniques were used to analyze the carbon isotope compositions at different internal growth zones of diamonds from Shandong and Liaoning in the North China Craton and Hunan in the Yangtze Craton.It was found that the carbon isotopic range of diamonds from the North China Craton are rather distinct from those of the Yangtze Craton;the former has a range of 6.0‰ to 2.0‰(relative to VPDB) with an average value of 3.0‰ in their core areas,which is consistent with global peridotitic diamonds;the diamonds from the Yangtze Craton,however,have a carbon isotopic range from 8.6‰ to 3.0‰ with an average value of 7.4‰ in their core areas,being more consistent with global eclogitic diamonds.The variations of carbon isotope ratios between different internal growth zones in individual diamonds were different in the three diamond localities studied.There was a clear correlation between changes in carbon isotopic composition and phases of diamond dissolution and new growth,while no correlation was observed between δ13C and internal inclusions.The variations suggest that the carbon isotopic compositions of mantle fluids were changing during the process of diamond crystallization,and that the heterogeneity of the carbon isotopic composition in mantle carbon reservoirs was a more important factor than carbon isotope fractionation in controlling the carbon isotopic compositions and their variation in diamonds.In addition,the preliminary results of in-situ nitrogen analyses demonstrated that the variation of carbon isotopic compositions between the core and outer growth zones does not correlate with nitrogen abundances,implying either that diamonds crystallized in an open environment or that the carbon isotopic composition and nitrogen contents in mantle fluids were controlled by other,not yet understood factors.The experimental results provide hints that the isotopic composition of carbon and its original sources were different in metasomatic fluids controlling diamond formation in the mantle beneath the North China Craton and the Yangtze Craton. 相似文献
124.
Initiation of neural induction by FGF signalling before gastrulation 总被引:17,自引:0,他引:17
During neural induction, the 'organizer' of the vertebrate embryo instructs neighbouring ectodermal cells to become nervous system rather than epidermis. This process is generally thought to occur around the mid-gastrula stage of embryogenesis. Here we report the isolation of ERNI, an early response gene to signals from the organizer (Hensen's node). Using ERNI as a marker, we present evidence that neural induction begins before gastrulation--much earlier in development than previously thought. We show that the organizer and some of its precursor cells produce a fibroblast growth factor signal, which can initiate, and is required for, neural induction. 相似文献
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126.
Christopher M. Stern Paul G. Mermelstein 《Cellular and molecular life sciences : CMLS》2010,67(22):3785-3795
Caveolin proteins physically interact with and compartmentalize membrane-localized signaling proteins to facilitate high-fidelity
intracellular signaling. Though primarily studied outside the nervous system, recent investigations have revealed that caveolin
proteins are key modulators of a variety of neuronal intracellular signaling pathways. Through both protein aggregation and
segregation, caveolin proteins can exert positive and negative influences on intracellular signaling. This review will detail
recent findings regarding caveolin function in the brain. 相似文献
127.