追求能源效率是材料研发的动力

在发动机舱内的塑料必须能承受发动机舱内持续生高的温度.     

Neuronal projections from the mesencephalic raphe nuclear complex to the suprachiasmatic nucleus and the deep pineal gland of the golden hamster (Mesocricetus auratus)

Neuronal projections from the mesencephalic raphe system to the suprachiasmatic nucleus and the pineal complex were mapped in this study of the golden hamster, by use of the anterograde tracer Phaseolus vulgaris-leucoagglutinin and the retrograde tracer cholera toxin subunit B. From the median raphe nucleus, a rostral projection ascended in the ventral part of the mesencephalon to continue in the medial forebrain bundle of the forebrain. Nerve fibres from this bundle innervated the ventral and medial parts of the suprachiasmatic nucleus. At the level of the interpeduncular nucleus of the mesencephalon, fibres of the ventral bundle bent dorsally to reach the epithalamic area and to continue in the forebrain in a periventricular position. Some of these fibres innervated the dorsal tip of the suprachiasmatic nucleus. The dorsal raphe nucleus was the origin of a nerve fibre bundle, located in the periaqueductal gray of the mesencephalon, innervating the deep pineal gland and pineal stalk. Injection of cholera toxin B into the suprachiasmatic nucleus labelled cells in the median raphe. Combination of the retrograde tracing from the suprachiasmatic nucleus and serotonin transmitter immunohistochemistry showed that some of the cholera toxin B-immunoreactive nerve cells also contained serotonin. Thus, this study of the golden hamster shows a serotonergic projection from the median raphe nucleus to the suprachiasmatic nucleus and a projection from the dorsal raphe nucleus to the deep pineal gland supporting physiological indications of an influence of serotonin on the photoreceptive circadian system of the brain.     

Dry Friction Between Laser-Patterned Surfaces: Role of Alignment, Structural Wavelength and Surface Chemistry

The ability to tune friction by tailoring surface topographies at micron length scales and by changing the relative orientation of crystallites at the atomic scale is well established. Here, we investigate if the two concepts combine, i.e. if the relative orientation of surfaces affects dry friction between laser-textured surfaces. Laser patterning was used on austenitic stainless steel substrates and on tribometer testing balls made of 100Cr6 to create linear periodic arrays with different structural wavelengths or periodicities (5, 9 and 18 ??m). Pairing each substrate with a ball of the same periodicity, the different arrays were subjected to dry sliding tests at 0°/90° relative alignment between the linear patters. We observe that the patterning reduces friction after running-in. The reduction increases with decreasing wavelength and also depends sensitively on the relative alignment and the chemistry of the sliding surfaces. Our results highlight the possibility to create tailored contacting surface geometries leading to tunable frictional properties.     

Light-emitting nanocomposite CdS-polymer electrospun fibres via in situ nanoparticle generation

We report on the simple, in situ generation of CdS nanocrystals inside electrospun polymer fibres by thermal decomposition of a cadmium thiolate precursor, leading to nanocomposite light-emitting fibres. The modifications induced in the precursor by the thermal decomposition are investigated by a morphological, structural and spectroscopic analysis of the resulting nanocomposite fibres. This approach allows us to overcome nanofabrication difficulties related to disfavoured micro- or nanofluidic molecular flow as given by the direct incorporation of particles in the electrospinning solution. This method therefore enables the synthesis of luminescent, CdS-based composite fibres with emission peaked in the visible range, suitable as building blocks for nanophotonic devices based on light-emitting nanomaterials.