UPLC-MS/MS法同时测定桃中氟吡菌酰胺和肟菌酯及其代谢产物

利用超高效液相色谱-串联质谱法（UPLC-MS/MS）,建立桃中氟吡菌酰胺及其主要代谢产物2-（三氟甲基）苯甲酰胺（BZM）和肟菌酯及其主要代谢产物肟菌酸的检测方法。去核粉碎后的桃样品经乙腈提取,C18吸附剂净化,UPLC-MS/MS分析,采用电喷雾正离子（ESI+）模式和多反应监测（MRM）,外标法定量。结果显示,在0.005～0.1 mg/L范围内,4种目标化合物的质量浓度与信号响应的峰面积均线性关系良好,相关系数（r）均大于0.99。在0.01, 0.1, 1, 3 mg/kg的添加水平下,4种目标化合物的平均回收率为77.7%～108.0%,相对标准偏差（RSD）为3.1%～17%。4种目标化合物的定量限（LOQ）均为0.01 mg/kg。该方法符合农药残留分析要求。     

基于碳酸钙模板的特殊形状层层组装微胶囊的制备

以Na_2CO_3和CaCl_2为原料,聚烯丙基胺盐酸盐(PAH)为添加剂,通过磁力搅拌和超声混合的方式分别制备了两面凸碟形仿血小板形状和纺锤形的碳酸钙微粒.仿血小板形状的碳酸钙微粒为球霰石晶相,而纺锤形碳酸钙微粒为文石晶相.模板微粒中均掺杂了少量PAH.溶液混合方式和PAH添加剂的协同作用导致了特殊形状碳酸钙微粒的形成.以这2种粒子为模板通过层层组装技术分别制备了仿血小板形状和纺锤形微胶囊.得到的微胶囊能够在水中分散良好并保持模板的特殊形状.     

银含量对二氧化硅固载磷钨酸银催化四氢呋喃聚合反应性能的影响

通过共浸渍法合成了一系列担载型杂多酸银盐催化剂Ag_xH_3-xPW/SiO₂ (x=0.5, 1.0, 1.5, 2.0, 2.5, 3.0),由于催化剂在极性溶剂中的不溶性, 在合成聚四氢呋喃的反应中显示了高反应活性和稳定性能. Ag离子取代含量和银盐的担载量对催化剂活性会产生显著影响. Ag 离子含量的不同会导致磷钨酸银盐的晶相结构和催化剂的酸性质发生变化. x=2.0 时, 催化剂Ag₂HPW/SiO₂达到最大酸强度和最高催化聚合反应活性. 当银盐Ag₂HPW的担载量为30% (质量分数)时, 催化剂能达到高分散度和高的四氢呋喃聚合反应活性. 与普通二氧化硅担载的磷钨酸催化剂HPW/SiO₂对比, 担载型磷钨酸银盐30%Ag₂HPW/SiO₂拥有优异的重复使用性能, 循环4 次后催化活性只有轻微下降. 通过引入Ag离子合成的新型担载磷钨酸银盐30%Ag₂HPW/SiO₂, 反应稳定性能明显改进, 得到拥有稳定平均分子量的产物聚四氢呋喃.     

Anti-function solution of uniaxial anisotropic Stoner-Wohlfarth model

The anti-trigonometric function is used to strictly solve the uniaxial anisotropic Stoner-Wohlfarth (SW) model, which can obtain the relation of the angle α (θ) between the magnetization (the anisotropy field) and the applied magnetic field. Using this analytic solution, the hysteresis loops of uniaxial anisotropic SW particles magnetized in typical directions could be numerically calculated. Then, the hysteresis loops are obtained in randomly distributed SW particle ensembles while ignoring the dipole interaction among them with the analytic solution. Finally, the correctness of the analytic solution is verified by the exact solutions of remanence, switching field, and coercivity from the SW model. The analytic solution provides an important reference for understanding the magnetizing and magnetization reversal processes of magnetic materials.     

Precision Higgs physics at the CEPC

The discovery of the Higgs boson with its mass around 125 GeV by the ATLAS and CMS Collaborations marked the beginning of a new era in high energy physics.The Higgs boson will be the subject of extensive studies of the ongoing LHC program.At the same time,lepton collider based Higgs factories have been proposed as a possible next step beyond the LHC,with its main goal to precisely measure the properties of the Higgs boson and probe potential new physics associated with the Higgs boson.The Circular Electron Positron Collider(CEPC)is one of such proposed Higgs factories.The CEPC is an e~+e~- circular collider proposed by and to be hosted in China.Located in a tunnel of approximately 100 km in circumference,it will operate at a center-of-mass energy of 240 GeV as the Higgs factory.In this paper,we present the first estimates on the precision of the Higgs boson property measurements achievable at the CEPC and discuss implications of these measurements.     

停流光谱研究稀土络合动力学

在水相中引入水溶性氨羧络合剂二乙三胺五乙酸(DTPA),可以在非平衡条件下实现相邻稀土元素的动力学分离。目前对加入DTPA调控稀土络合萃取速率的原因尚不清楚,无法解释稀土动力学分离的机理。采用快速动力学停流光谱,研究了稀土离子与DTPA络合反应动力学规律。结果表明,随溶液pH值和DTPA浓度变化,稀土离子与DTPA的络合与解离速率存在明显差异。该研究为调控稀土离子络合或解离速率差异实现不同稀土离子间动力学分离提供了理论依据。     

新型缓变锥型PCF结构接口耦合损耗特性

提出一种新型的缓变锥型光纤接口器件。该接口器件是一个长度为150mm左右的缓变锥型光子晶体光纤。利用有限元方法对模场直径差别较大的不同光纤进行拼接时的损耗问题进行研究。研究结果表明:在模场直径分别为9μm和10.4μm的光纤之间加入锥型光纤后可以有效降低耦合损耗,并且在不同波长下耦合损耗都维持在一个较低水平。因此,该接口器件能够实现光纤拼接时物理结构的过渡和不同模场直径的转换,从而使拼接损耗降到最低。