SY-202型高速离子交换色谱仪电路设计问题讨论

四川分析仪器厂生产的SY-202型高速离子交换色谱仪(以下简称SY-202)在电路设计上存在一定问题,分析有机酸时出现异常现象: 1.色谱峰严重拖尾,相邻的色谱峰分不开(图1A)。     

中红外激光晶体Dy:PbGa2S4的生长与器件制备

镝掺杂硫镓铅(Dy:PbGa2S4,Dy:PGS)晶体是一种性能优良、具有潜在应用价值的中红外激光介质材料.为推动该晶体的实用化研究,迫切需要制备出大尺寸高品质Dy:PGS单晶.本研究采用自制的双温区管式炉成功合成Dy:PbGa2S4多晶,单次合成量达到230 g;首次采用竖直梯度冷凝法制备该晶体并成功生长出大尺寸高质量Dy:PbGa2S4单晶,尺寸达到φ27 mm×100 mm;通过切割和抛光等处理工艺,成功加工出Dy:PbGa2S4晶体器件,为下一步的激光应用研究打下了坚实基础.     

超高效液相色谱串联质谱法对鳗鱼中大环内酯类、喹诺酮类和磺胺类兽药残留量的同时测定

建立了同时测定鳗鱼组织中大环内酯、喹诺酮和磺胺类共25种兽药残留的超高效液相色谱串联质谱分析方法.采用多反应监测模式进行测定,外标法定量,鳗鱼组织在酸化条件下用乙腈提取,经正己烷除油,检出限为0.1～0.2μg/kg.除泰乐菌素外,回收率均在60%～97%之间,相对偏差不大于12.6%,线性回归相关系数在0.9974～0.9999之间.     

聚乙二醇-金纳米棒介导的近红外光热抑菌作用

种子生长法合成纵向表面等离子体共振吸收峰为785 nm的金纳米棒,并对其表面进行聚乙二醇(PEG)修饰,研究了表面修饰PEG的金纳米棒(polyethylene glycol modified gold nanorods,PEG-GNR)的光热转化效应,并测试了其细胞毒性。以革兰氏阳性菌金黄色葡萄球菌、蜡状芽孢杆菌,革兰氏阴性菌大肠埃希氏菌及铜绿假单胞菌为细菌模型,详细研究了PEG-GNR在808nm波长近红外激光照射下金纳米棒浓度和照射功率对抑菌效果的影响。结果表明,PEG-GNR对革兰氏阳性菌和革兰氏阴性菌在近红外照射下均有较好的抑菌效果,并且抑菌效果与金纳米棒的浓度和照射功率有着密切的关系;结合荧光显微镜和透射电子显微镜对细菌坏死状况的观察,初步证实细菌对PEG-GNR有效吸收是近红外光热杀菌的关键因素。     

Asymmetric vortices flow over slender body and its active control at high angle of attack

The studies of asymmetric vortices flow over slender body and its active control at high angles of attack have significant importance for both academic field and engineering area. This paper attempts to provide an update state of art to the investigations on the fields of forebody asymmetric vortices. This review emphasizes the correlation between micro-perturbation on the model nose and its response and evolution behaviors of the asymmetric vortices. The critical issues are discussed, which include the formation and evolution mechanism of asymmetric multi-vortices; main behaviors of asymmetric vortices flow including its deterministic feature and vortices flow structure; the evolution and development of asymmetric vortices under the perturbation on the model nose; forebody vortex active control especially discussed micro-perturbation active control concept and technique in more detail. However present understanding in this area is still very limited and this paper tries to identify the key unknown problems in the concluding remarks. The project supported by the National Natural Science Foundation of China (10172017), Aeronautical Science Foundation of China (02A51048) and Foundation of National Key Laboratory of Aerodynamic Design and Research (51462020504HK0101)     

双束参考光全息图

普通全息图是由物光波和一束参考光波干涉而成的,再现时只能在某一方向上很狭窄的视角范围内才能观察到再现像。为了扩大观察全息图再现像的视场,提出一些新的方法制作全息图,如彩色全息图,合成全息图,及利用全息图的角度灵敏性多次记录的体积全息图等等。这些方法都需要多次曝光,制作工艺要求高,过程复杂。本文提出通过适当设置光路,排除影响衍射效率的部分因素,获得的双束参考光全息图,同样可以扩大再现像的视场,且只需一次曝光,工艺要求低,过程较为简便。     

压力对Zr46.75Ti8.25 Cu7.5Ni10Be27.5大块非晶合金玻璃转变和晶化动力学的影响

利用X射线衍射和差示扫描量热分析研究了高温高压下Zr46.75Ti8.25Cu7.5Ni10Be27.5大块非晶合金的玻璃转变和晶化行为,结果发现压力降低了该大块非晶合金中的自由体积、热焓和晶化激活能.     

磷在硅表面氧化层中的扩散

用示踪原子方法,研究了磷(Na₂HP³²O₄)在p型硅表面氧化层中的扩散。硅单晶的电阻率为5—6欧姆·厘米。氧化层是在高温下水汽中生长的,其厚度为0.5—0.6微米,是用灵敏度为10^-5克/刻度的微量天平测定的。发现在1245℃时氧化层的生长规律服从X^1.85=1.4×10^-2t,其中X为氧化层的厚度,单位为微米;t为氧化层的生长时间,单位为分钟。其红外吸收的测量结果与文献中的数据基本一致。扩散是在充满空气的封闭石英管中进行的,扩散温度为700—1250℃,扩散时间从4分钟到5小时。实验结果表明,磷在SiO₂层中的浓度分布不能直接用菲克第二定律描述,它可以看成是一个均匀分布和一个遵守菲克第二定律的分布的迭加。按后一种分布得到在700—1200℃范围内的扩散系数的温度依赖关系:D=1.9×10^-9exp(-1.1/kT)厘米²/秒。均匀分布部分的浓度为(1—8)×10¹⁹原子/厘米³。大中对所用方法和所得结果作了简单讨论.     

A critical pattern of crossflow around a slender

IntroductionModernhigh_performancefightersoftenrequiretobeoperatedunderafairlylargeangleofattacksoastoachieveexcellentmaneuverabilityandagility .Atsuchlargeangleofattack ,asymmetricallee_sidevortexflowwillformatthefrontpartofthefuselage .Sothatsuchagreats…     

Stability of the crossflow pattern around a slender and influence of disturbance

Topological structure and stability of a slender cross flow is discussed by the stability theory of dynamic system. The inner boundary of flow field was limiting streamline and it was proved that the topological structure connected saddles by limiting streamline is stable. It is proved that the development of slender vortices leads to the change of topological structure about cross flow. And it is the change from stable and symmetrical vortices flow pattern to unstable and symmetrical vortices flow pattern, and then to stable and asymmetrical vortices flow pattern due to little disturbance which leads to the development of asymmetrical slender vortices. The influence of disturbance to flowfield structure was discussed by unfolding theory too.