欧盟对熏剂产品制定最大残留限制标准

最近欧盟委员会对用于采收后的熏剂产品进行了列表登记，这些熏剂将不再受欧盟新的最大残留限制标准的约束。该表属于新的欧盟农药最大残留限制标准管理规则396／2005的附录VII的一部分，旨在帮助那些在收割采收后使用了熏剂产品的农产品免遭贸易损害。     

读友信箱

耳机的基本知识及选购 Q市面上耳机那么多,它们都有什么不同,又该如何选购呢?另外,好些耳机标称的低频下限都在20Hz以下,真有这么低?     

Experimental Research on Erbium-doped Superfluorescent Fiber Source

The effects of the variations in fiber length, fiber mirror reflectance on efficiency and output power are experimentally investigated for erbium-doped double pass backward superfluorescent fiber sources (SFSs). The influence of fiber length on mean wavelength stability (MWS) has also been demonstrated. By incorporating a short section of un-pumped erbium-doped fiber (EDF) at the output port, the pump power dependent on MWS becomes independent of pumped EDF length. This is a novel phenomenon that hasn‘t been reported up to now,and should be helpful to SFS fabrication and theory analysis. By using a fiber Michelson interferometer as spectrum slicing component,a multi-wavelength fiber source (MWFS) with ～20 channels (from 1542nm to 1559nm) is got. The MWFS has a channel spacing of ～0. 8 nm which satisfies ITUstandard. The intensity fluctuation among channels is less than 0.5dB,and the extinction ratio of all channels is above 14dB. This kind of MWFS should be useful to wavelength division multiplexing systems.     

永年县抢抓时机集蓄雨洪资源

今年汛期永年县在确保安全度汛的前提下，按照“防汛抗旱科学化、雨洪利用资源化”的思路，抢抓后汛期集蓄雨水的黄金时机，充分发挥水利工程调蓄功能，千方百计拦蓄地表水，截至目前，累计蓄水600万m^3。     

纯棉针织布上涂料拔活性印花的应用

在纯棉织物上涂料拔活性印花不同于在机织物上印花，加工较为困难．尤其对于成衣和手工台板印花工厂。本文介绍了在上述情况下为取得较好的涂料拔活性印花效果的实际经验．包括活性染料及涂料的选择；一般涂料拔活性印花和多套色涂料印花、拔染两步法工艺的处方用料、工艺过程和工艺条件等。     

异型旅游梁抽油机后驴头连接套的焊接与加工

异型游梁抽动机与常规游梁抽油机相比，前者在结构上增设了后驴头钢绳软连接。后头与游梁的连接是否可靠是该型机的重要质量保证之一。采用在连接套上增设圆挡环的方案，将连接套内孔焊接变形的问题转移到前道工序之前和圆挡环外圆上，从而提高了连接套的形位精度。用新方案焊接后，销轴与连接套内孔的配合间隙最大为＋０．４ｍｍ，最小为＋０．１７ｍｍ，大大提高了装配质量，标准公差等级由原ＩＴ１２级提高到ＩＴ１０级。