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991.
Nissan Zeldes 《Archive for History of Exact Sciences》2009,63(3):289-323
The present article considers Giulio Racah’s contributions to general physical theory and his establishment of theoretical
physics as a discipline in Israel. Racah developed mathematical methods that are based on tensor operators and continuous
groups. These methods revolutionized spectroscopy. Currently, these are essential research tools in atomic, nuclear and elementary
particle physics. He himself applied them to modernizing theoretical atomic spectroscopy. Racah laid the foundations of theoretical
physics in Israel. He educated several generations of Israeli physicists, and put Israel on the world map of physics. 相似文献
992.
A dragonfly wing consists of membranes and both longitudinal and cross veins. We observed the microstructure cross-section
at several locations in the dragonfly wing using environmental scanning electron microscopy (ESEM). The organic nature of
the junction between the vein and the membrane was clearly identifiable. The membrane was divided into two layers, the upper
epidermis and the lower epidermis. These layers extend around the sandwich structure vein, and combine with the adjacent membrane
at a symmetrical location along the vein. Thus, we defined this as an organic junction between the vein and the membranes.
The organic junction is able to form a tight corrugation angle, which dramatically increases both the warping rigidity and
the strength of the wing, but not the torsional rigidity. The torsional deformation is primarily controlled by the microstructure
of the longitudinal veins, and is based on the relative rotation angle between the epidermal layer and the inner layer of
the vein that forms the zigzag section. 相似文献
993.
Lucas Matt Stylianos Michalakis Franz Hofmann Verena Hammelmann Andreas Ludwig Martin Biel Thomas Kleppisch 《Cellular and molecular life sciences : CMLS》2011,68(1):125-137
Neuronal hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are known to modulate spontaneous activity, resting
membrane potential, input resistance, afterpotential, rebound activity, and dendritic integration. To evaluate the role of
HCN2 for hippocampal synaptic plasticity, we recorded long-term potentiation (LTP) in the direct perforant path (PP) to CA1
pyramidal cells. LTP was enhanced in mice carrying a global deletion of the channel (HCN2−/−) but not in a pyramidal neuron-restricted knockout. This precludes an influence of HCN2 located in postsynaptic pyramidal
neurons. Additionally, the selective HCN blocker zatebradine reduced the activity of oriens-lacunosum moleculare interneurons
in wild-type but not HCN2−/− mice and decreased the frequency of spontaneous inhibitory currents in postsynaptic CA1 pyramidal cells. Finally, we found
amplified LTP in the PP of mice carrying an interneuron-specific deletion of HCN2. We conclude that HCN2 channels in inhibitory
interneurons modulate synaptic plasticity in the PP by facilitating the GABAergic output onto pyramidal neurons. 相似文献
994.
Laurent Nottale 《Foundations of Science》2011,16(4):307-309
We give a “direction for use” of the scale relativity theory and apply it to an example of spontaneous multiscale integration
including four embedded levels of organization (intracellular, cell, tissue and organism-like levels). We conclude by an update
of our analysis of the arctic sea ice melting. 相似文献
995.
对青海野生大黄茶营养成分进行了分析,结果表明:野生大黄茶中含有蛋白质、脂肪、维生素C、胡萝卜素等营养物质,其中维生素C和胡萝卜素含量丰富,分别达到47.97mg/100g和0.41mg/kg,且氨基酸种类较多。青海野生大黄茶保持了大黄的有效药用成份-大黄素,是一种饮用方便的新型保健品。 相似文献
996.
熊红珊 《华中科技大学学报(自然科学版)》1999,(Z1)
通过对深圳市滨河污水处理厂污不处理集散控制系统和办公自动化管理信息系统的分析,将先后建成的生产型和管理型两套系统,组成一个完整的统一网络,实现了异构型双网互联 相似文献
997.
建立了HZY型振动运输机力学模型,运用相对运动原理对其振动规律进行了分析,探索了产生扭转振动的原因,推导出了稳定同步振动的运动方程,并提出了实现稳定同步运转的判据及相应的技术措施.这对采用双电机进行自同步振动机的设计具有指导意义. 相似文献
998.
John Hamilton 《系统科学与系统工程学报(英文版)》2007,16(4):414-423
Modeling a business to match its customer perceived (and customer desired) outcomes, remains an on-going task. This paper considers shows how a service value networks (SVNs) approach may be engaged to model, and deliver, understanding of the front-end business and its direct engagement with its immediate (or front-end) customers. These front-end customers may be either: (1) its off-line, in-store customers - engaging directly with the business sales staff (or representative), or-(2) its on-line, virtual customers - engaging with the business via internet or remote access. In this situation, both the business, and the customer draw upon their respective viewpoints, and both sides influence the interaction. External to these business and customer influences are additional factors that capture the immediate and broader global effects - termed environmental effects. These three business-customer engagement areas of influence are captured by a SVN SEM approach.
Without a business-customer encounter of some kind the likelihood of a services business, and a prospecting customer, successfully engaging in an exchange process is reduced. This exchange may be a physical, and/or services exchange, and/or an information and/or ideas exchange. To the business, this encounter is, in effect, a trade, and as a result, the business targets acquiring an economic exchange that will ultimately deliver a net positive economic outcome. To the customer, external and internal information feeds, servicing, perceived value, and satisfaction, are key encounter drivers. SVNs offers a new way to understand the business-customer encounter, and to then utilize this acquired knowledge to either: (1) build a strategic management model, or (2) reengineer its business networks, and to then create a re-positioned, more customer-aligned business operation - one that is capable of delivering win - win, competitive business-customer solutions. 相似文献
Without a business-customer encounter of some kind the likelihood of a services business, and a prospecting customer, successfully engaging in an exchange process is reduced. This exchange may be a physical, and/or services exchange, and/or an information and/or ideas exchange. To the business, this encounter is, in effect, a trade, and as a result, the business targets acquiring an economic exchange that will ultimately deliver a net positive economic outcome. To the customer, external and internal information feeds, servicing, perceived value, and satisfaction, are key encounter drivers. SVNs offers a new way to understand the business-customer encounter, and to then utilize this acquired knowledge to either: (1) build a strategic management model, or (2) reengineer its business networks, and to then create a re-positioned, more customer-aligned business operation - one that is capable of delivering win - win, competitive business-customer solutions. 相似文献
999.
本书内容简练而全面,是一本很好的生物信息学教材。本书主要特点有:(1)尽可能避开繁琐的数学公式,详细介绍了算法的技术细节,免去了读者必须具备复杂的计算背景才能理解算法的前提;(2)恰当地使用图例,使读者更容易理解书中的内容;(3)广泛参阅并综合了生物信息学各关键领域的文献,帮助读者尽快掌握生物信息学的全貌。本书不仅介绍了结构生物信息学,还涵盖了比较基因组学和功能基因组学等较新领域的内容。 相似文献
1000.
服装与表演专业属新设专业。目前在我国尚处于探索阶段,有关该专业的办学方向、课程结构还不够合理。本文试图通过对服装表演现状的分析并结合我院的教学实践为建立符合社会需要的服装模特的培养模式提供一定的理论依据。 相似文献