外贸英文函电中“时间”的特点与外贸实务

通过对外贸英文函电当中某些介词副词作用的研究，论述了这些词在语法及实务意义上的不同及这些词的不同运用所产生的重要意义．     

热轧钢材显微组织-力学性能预报和控制技术

概述了热轧产品显微组织演变的计算机模型以及显微组织与力学性能之间的关系 .简要阐述了组织 性能预报和控制技术的发展历程和发展趋势 ,讨论了组织 性能预报和控制技术在生产上的应用     

Factors of 3GWC systems for drawing up customized strategies of promotion

This study utilizes fuzzy analytic hierarchy process(FAHP) to analyze decision-making patterns with regard to third-generation wireless communications(3GWC) service adoption,and to provide customized strategic recommendations to suppliers of 3GWC services regarding marketing and resource allocation in the context of the Chinese 3GWC market.First of all,a three-layer hierarchy of 3GWC adoption factors is developed by referring to the relevant literature and industry reports.A questionnaire of pairwise com...     

Improved auditory spatial tuning in blind humans.

Despite reports of improved auditory discrimination capabilities in blind humans and visually deprived animals, there is no general agreement as to the nature or pervasiveness of such compensatory sensory enhancements. Neuroimaging studies have pointed out differences in cerebral organization between blind and sighted humans, but the relationship between these altered cortical activation patterns and auditory sensory acuity remains unclear. Here we compare behavioural and electrophysiological indices of spatial tuning within central and peripheral auditory space in congenitally blind and normally sighted but blindfolded adults to test the hypothesis (raised by earlier studies of the effects of auditory deprivation on visual processing) that the effects of visual deprivation might be more pronounced for processing peripheral sounds. We find that blind participants displayed localization abilities that were superior to those of sighted controls, but only when attending to sounds in peripheral auditory space. Electrophysiological recordings obtained at the same time revealed sharper tuning of early spatial attention mechanisms in the blind subjects. Differences in the scalp distribution of brain electrical activity between the two groups suggest a compensatory reorganization of brain areas in the blind that may contribute to the improved spatial resolution for peripheral sound sources.     

霜层导热系数的实验研究

实验研究水蒸汽凝华结霜过程中在冷壁面上形成的霜层的导热系数,并以此验证作者曾提出的霜层导热系数的理论结果．     

Early specification of limb muscle precursor cells by the homeobox gene Lbx1h.

During vertebrate embryogenesis, myogenic precursor cells of limb muscles delaminate from the ventro-lateral edge of the somitic dermomyotome and migrate to the limb buds, where they congregate into dorsal and ventral muscle masses. It has been proposed that the surrounding connective tissue controls muscle pattern formation in limbs. Regulatory molecules such as receptor tyrosine kinases like c-Met ( ref. 6) and those encoded by homeobox-containing genes, including c-Met (ref. 6), Tbx1 (ref. 7), Mox2 (ref. 8), Six1 and Six2 (ref. 9), Pitx2, Pax3 (refs 10,11) and Lbx1h (refs 12,13), are expressed in migrating limb precursor cells. The role of these genes in the patterning of limb muscles is unknown, although mutation of Pax3 or Met causes disruption of limb muscle development at an initial step, disturbing the epithelial-to-mesenchymal transition of the somitic epithelium. No limb muscle cells form in these mutants, and the early loss of myogenic precursor cells prevented an analysis of later functions of these genes during limb muscle development. Based on quail-chick chimaera studies, it was assumed that a cell-autonomous contribution of myogenic cells to the formation of individual limb muscles is negligible, and that an instructive role of limb mesenchyme is critical in this process. Here we show that Lbx1h determines migratory routes of muscle precursor cells in a cell-autonomous manner, thereby leading to the formation of distinct limb muscle patterns. Inactivation of Lbx1h, which is specifically expressed in migrating muscle precursor cells, led to a lack of extensor muscles in forelimbs and an absence of muscles in hindlimbs. The defect was caused by the failure of all muscle precursor cells of hindlimbs and of precursor cells of extensor muscles of forelimbs to migrate to their corresponding muscle anlagen. Our results demonstrate that Lbx1h is a key regulator of muscle precursor cell migration and is required for the acquisition of dorsal identities of forelimb muscles.     

A membrane-access mechanism of ion channel inhibition by voltage sensor toxins from spider venom

Venomous animals produce small protein toxins that inhibit ion channels with high affinity. In several well-studied cases the inhibitory proteins are water-soluble and bind at a channel's aqueous-exposed extracellular surface. Here we show that a voltage-sensor toxin (VSTX1) from the Chilean Rose Tarantula (Grammostola spatulata) reaches its target by partitioning into the lipid membrane. Lipid membrane partitioning serves two purposes: to localize the toxin in the membrane where the voltage sensor resides and to exploit the free energy of partitioning to achieve apparent high-affinity inhibition. VSTX1, small hydrophobic poisons and anaesthetic molecules reveal a common theme of voltage sensor inhibition through lipid membrane access. The apparent requirement for such access is consistent with the recent proposal that the sensor in voltage-dependent K+ channels is located at the membrane-protein interface.