自注入式固体Ce~(3+)∶LuLiF_4激光器中紫外亚纳秒脉冲序列的产生

提出一个注入式结构，它可以用在各种脉冲激光器中产生短脉冲序列。在这个结构中，从短腔种子激光器产生单一的亚纳秒脉冲，这个种子脉冲在同一增益介质中被再生放大，直到增益衰减到最小。用一个１０ｎｓ脉冲激光器泵浦固体激光介质Ｃｅ３＋∶ＬｕＬｉＦ４，直接地，被动地产生了紫外亚纳秒脉冲序列。     

自注入式固体Ce^3＋：LuLiF4激光器中紫外亚纳秒脉冲序列的产生

提出了一个注入式结构，它可以用在各种脉冲激光器中产生短脉冲序列。在 个结构中，从短腔激光器产生单一的亚纳秒脉冲，这个种子脉冲在同一地益介质中被再生放大，直到增益衰减到最小。     

石英砂固体分散剂制样的裂解气相色谱法测定涤/毛纤维混纺比列

基于纵型微型炉裂解器的裂解气相色谱法(Py-GC)建立了涤/毛纤维混纺比例的测定方法。以石英砂为固体质量分散剂,将样品加入其中碾磨成粉末后称量进样,在550℃的裂解温度下得到相应的裂解色谱图,依据各自特征裂解谱图与释放气体分析曲线可识别涤纶与羊毛纤维;选择涤/毛二元混纺纤维裂解谱图上涤纶的特征裂解产物——联苯为定量峰,计算混纺纤维中涤纶的质量百分含量,进而推算出羊毛纤维的含量。样品和石英砂的最佳配比为0.02 g∶4 g,涤纶质量在0.0256~0.2048 mg范围内联苯的线性良好,相关系数R2=0.9952。对不同涤/毛混纺比例的实际样品进行了测定,相对标准偏差RSD<3%(n=3);本法与国标法所得结果的偏差小于5%。结果表明,本方法简便、准确,适合涤/毛二元混纺纤维混纺比例的质控分析。     

用于产生太赫超宽边带光谱的新型电／光调制器

报道了利用周期性的极转技术制作准速度匹配型电／光调制器，并以这种调制器产生超宽边带光谱的结果。电光晶体ＬｉＴａＯ３的极性分布周期的反转之后，在１６．２５ＧＨｚ的调制频率下，实现了微波与光波的准速度匹配，可以不局限于调制频率的高低，从而在增加相互作用长度的前提下充分提高调效率，调制度已达到５７ｒａｄ，产生的宽边带光谱的半值全宽为１．８５ＴＨｚ。     

聚四氟乙烯毛细管在线富集分离痕量钌(Ⅲ)及荧光测定

利用碱性条件下聚四氟乙烯毛细管(PTFEtube)对钌-邻菲罗啉具有富集作用,建立了单道流动注射在线富集分离及检测痕量钌的荧光分析法。本方法考察了毛细管壁、流速、pH值、温度及掩蔽剂EDTA、干扰离子等因素对富集效果的影响。当浓缩液pH值为11.8,邻菲罗啉浓度为1×10-4mol/L,浓缩和洗脱速度为3.8mL/min及EDTA的浓度为2×10-2mol/L时,获得最佳结果。在优化的实验条件下,该方法在0~50ng/L范围内呈良好的线性关系,检出限为0.8ng/L(S/N=3);RSD=2.1%(n=3)。     

SAD phasing by OASIS at different resolutions down to 0.30 nm and below

Single-wavelength anomalous diffraction （SAD） phasing is increasingly important in solving de novo protein structures. Direct methods have been proved very efficient in SAD phasing. This paper aims at probing the low-resolution limit of direct-method SAD phasing. Two known proteins TT0570 and Tom70p were used as test samples. Sulfur-SAD data of the protein TT0570 were collected with conventional Cu-Kα source at 0.18 nm resolution. Its truncated subsets respectively at 0.21, 0.30, 0.35 and 0.40 nm resolutions were used in the test. TT0570 Cu-Kα sulfur-SAD data have an expected Bijvoet ratio 〈 ｜△F｜ 〉 / 〈 F 〉 ～ 0.55%. In the 0.21 nm case, a single run of OASIS-DM-ARP/wARP led automatically to a model containing 1178 of the total 1206 residues all docked into the sequence. In 0.30 and 0.35 nm cases, SAD phasing by OASIS-DM led to traceable electron density maps. In the 0.40 nm case, SAD phasing by OASIS-DM resulted in a degraded electron density map, which may be difficult to trace but still contains useful secondary-structure information. Test on real 0.33 nm selenium-SAD data of the protein Tom70p showed that even automatic model building was not successful, the combination of manual tracing and direct-method fragment extension was capable of significantly improving the electron-density map. This provides the possibility of effectively improving the manually built model before structure refinement is performed.