斜螺旋面的近似展开

本文用计算法论述了斜螺旋面展开图的近似画法，为斜螺旋面展开图提供亍一个较简便的方法。     

红霉素发酵过程前期参数相关分析及调控

对红霉素发酵过程前期调控策略进行了研究,从宏观代谢流的变化着手,对表征细胞代谢特征的参数进行了相关分析,对发酵前期的摄氧率(OUR)、二氧化碳释放率(CER)及呼吸商(RQ)相关变化及红霉素发酵前期CER与pH的变化进行了分析,确定了合适的调控方式,在工业规模发酵罐上通过控制发酵过程前期补糖速率等措施,使发酵平均水平从原来的4500u／mL提高到了6000u／mL。     

对苯二甲酸中微量杂质HPLC分析条件的优化

用离子交换高效液相色谱法分析对苯二甲酸中的微量杂质,并对该方法进行了系统的优化。通过选择流动相pH值使缓冲溶液的浓度降低至0．13mol／L,分析周期缩短至10min以下。结果表明：该方法的工作曲线相关系数在0．9998以上,回收率为98．7％～102．2％,相对标准偏差小于3．6％。     

An infrared flash contemporaneous with the gamma-rays of GRB 041219a

The explosion that results in a cosmic gamma-ray burst (GRB) is thought to produce emission from two physical processes: the central engine gives rise to the high-energy emission of the burst through internal shocking, and the subsequent interaction of the flow with the external environment produces long-wavelength afterglows. Although observations of afterglows continue to refine our understanding of GRB progenitors and relativistic shocks, gamma-ray observations alone have not yielded a clear picture of the origin of the prompt emission nor details of the central engine. Only one concurrent visible-light transient has been found and it was associated with emission from an external shock. Here we report the discovery of infrared emission contemporaneous with a GRB, beginning 7.2 minutes after the onset of GRB 041219a (ref. 8). We acquired 21 images during the active phase of the burst, yielding early multi-colour observations. Our analysis of the initial infrared pulse suggests an origin consistent with internal shocks.     

The nature and origin of interstellar diamond

Microscopic diamond was recently discovered in oxidized acid residues from several carbonaceous chondrite meteorites (for example, the C delta component of the Allende meteorite). Some of the reported properties of C delta seem in conflict with those expected of diamond. Here we present high spatial resolution analytical data which may help to explain such results. The C delta diamond is an extremely fine-grained (0.5-10 nm) single-phase material, but surface and interfacial carbon atoms, which may comprise as much as 25% of the total, impart an 'amorphous' character to some spectral data. These data support the proposed high-pressure conversion of amorphous carbon and graphite into diamonds due to grain-grain collisions in the interstellar medium although a low-pressure mechanism of formation cannot be ruled out.     

Large, wetland-associated mayflies (Ephemeroptera) of Glacier National Park, Montana

We describe species richness and habitat associations of mayflies (Ephemeroptera) collected during amphibian surveys of 355 water bodies in Glacier National Park (NP), Montana, in 2006–2008. We collected 9 taxa (in 7 genera) of mayflies that were identifiable to species. Callibaetis ferrugineus hageni was collected most frequently, followed by Siphlonurus occidentalis, S. phyllis, Ameletus celer, A. similior, Parameletus columbiae, Ephemerella dorothea infrequens, Baetis bicaudatus, and Leptophlebia cupida. Siphlonurus phyllis had not been reported in the western United States prior to our surveys, and P. columbiae is a species of concern in the region. The identifications of 4 additional taxa were uncertain due to the poor condition of specimens found at only one site ( Centroptilum sp. and Paraleptophlebia sp.) or because nymphal specimens could not be confidently identified ( Cinygma sp. and Cinygmula sp.). Species richness of mayflies in wetlands seems low compared to that in streams and lakes in Glacier National Park. We found the most species of mayflies in beaver ponds, where we detected some species not commonly associated with lentic water bodies. Our survey was the first extensive survey of wetland invertebrates in Glacier NP and only the second that we are aware of in western Montana.