A magnetically collimated jet from an evolved star

Planetary nebulae often have asymmetric shapes, even though their progenitor stars were symmetric; this structure could be the result of collimated jets from the evolved stars before they enter the planetary nebula phase. Theoretical models have shown that magnetic fields could be the dominant source of jet-collimation in evolved stars, just as these fields are thought to collimate outflows in other astrophysical sources, such as active galactic nuclei and proto-stars. But hitherto there have been no direct observations of both the magnetic field direction and strength in any collimated jet. Here we report measurements of the polarization of water vapour masers that trace the precessing jet emanating from the asymptotic giant branch star W43A (at a distance of 2.6 kpc from the Sun), which is undergoing rapid evolution into a planetary nebula. The masers occur in two clusters at opposing tips of the jets, approximately 1,000 au from the star. We conclude from the data that the magnetic field is indeed collimating the jet.     

承载供应链管理的客户关系链管理分析与建模

指出了客户关系管理的概念不足,以实际例子引出客户关系链的概念,并分析指出客户关系链可以承载供应链的运作管理.利用Markov链对该过程建模,对简单的情况进行了分析和计算,并给出了如果忽略了客户下游信息,企业所受到的损失分析.并同供应链系统作了类比.     

一个用于中小型企业的扩展ERP软件流程集成模型分析

在以前工作的基础上,主要讨论了一个将ERP(enterpriseresourceplanning,企业资源规划)、SRM(supplierrelationshipmanagement,供应商关系管理)、CRM(customerrelationshipmanagement,客户关系管理)集成为一体的简化流程模型.论文在界定了几个基本概念的基础上,描述了接触中心的发出流程和接收流程功能,讨论了对ERP软件的流程及核心管理和CRM软件的流程及核心管理思路,研究了对ERP同CRM的关联点,仿照对CRM的分析,对SRM做了类似的分析,最后给出了以关系为企业围墙的扩展ERP简化模型.