基体改进效应石墨炉原子吸收测定易挥发性元素砷、硒、碲、银、锑和铋

石墨炉原子吸收测定易挥发性痕量元素时,往往在原子化以前的灰化阶段即挥发损失以致分析结果偏低.同时又由于允许的灰化温度较低,样品中的基体不能驱尽,因此在原子化阶段产生严重的背景吸收.为消除这类干扰,文献报道采用基体改进技术,即在待测样品溶液中或在石墨炉中加入某种化学试剂,将待测元素转变为较稳定的化合物,从而有利于提高灰化温度,防止灰化损失和消除基体干扰.我们已应用微克量钯作为基体改进剂测定废水中痕量汞和海水中铅.     

用于陶瓷快速制造的聚乙烯醇凝胶热分解研究

用DSC、IR及XRD研究了用于陶瓷快速制造的聚乙烯醇凝胶热分解过程。利用SEM观察了两种温度制度下金红石瓷的显微结构。结果表明:由于生成双二醇结构,胶凝后的聚乙烯醇红外光谱短波附近的衍射已经基本为Na2B4O7.10H2O的谱线所替代。胶凝后的聚乙烯醇DSC曲线表明,其分解温度提高约42℃,主要由于双二醇结构降低了主链旋转运动的自由度。SEM分析表明,在凝胶分解峰值前降低升温速率以及在峰值处延长保温时间有利于降低陶瓷气孔率。     

Fluorescence Properties of Porphyrin Dimers Incorporating an Anhydride Linker

IntroductionOligomeric porphyrins play a number of criticalbiological roles in many processes, such as energytransfer and electron transfer, molecular binding, mul-tielectron redox catalysis and light harvest[1,2]. Amongthe arrays of covalently linked por…     

L-模糊伪理想及其性质

给出了L-模糊伪理想的概念,借助L-模糊集的几种截集给出了它的刻画,研究了它的运算性质。     

基于滑模状态观测器的不确定控制系统鲁棒性诊断

针对不确定控制系统的故障诊断问题,通过对滑模控制系统的鲁棒性分析,提出了利用滑模观测器进行故障诊断的方法。该方法能够稳定地估计不确定控制系统正常扰动下的状态响应,进而对于系统出现的故障扰动实现检测诊断,仿真结果验证了该方法的有效性。     

新型超低温探头在分析与科研中的应用

过去的几十年里,超低温探头技术是使得NMR 灵敏度得到极大提高的技术上的唯一进步. 本文详细介绍了布鲁克各种类型超低温探头的技术创新和应用实验. 布鲁克超低温探头在灵敏度上的飞跃,使得科学家可以研究以前无法研究的小量样品,样品测试的通量最高可增加16倍. 各种新型的超低温探头也将把超低温探头的应用扩展到新的领域.     

??ê????????????FRP??????????

通过对预应力FRP放张后端部应力状态的分析后发现,适当加大粘结层的厚度和提高 粘结层的变形性能可大幅度提高端部粘结锚固的能力,满足预应力加固的需要. 附加 的简易锚固措施可进一步提高锚固能力和可靠性. 分析为预应力FRP加固技术的成本降低 和施工工艺简化提供理论依据.     

Entanglement Dynamics and Bell Violations of Two Atoms in Tavis-Cummings Model with Phase Decoherence

Considering the dipole-dipole coupling intensity between two atoms and the field in the Fock state, the entanglement dynamics between two atoms that are initially entangled in the system of two two-level atoms coupled to a single mode cavity in the presence of phase decoherence has been investigated. The two-atom entanglement appears with periodicity without considering phase decoherence, however, the phase decoherence causes the decay of entanglement between two atoms, with the increasing of the phase decoherence coefficient, the entanglement will quickly become a constant value, which is affected by the two-atom initial state. Meanwhile the two-atom quantum state will forever stay in the maximal entangled state when the initial state is proper even in the presence of phase decoherence. On the other hand, the Bell violation and the entanglement do not satisfy the monotonous relation, a large Bell violation implies the presence of a large amount of entanglement under certain conditions, while a large Bell violation corresponds to a little amount of entanglement in certain situations. However, the violation of Bell-CHSH inequality can reach the maximal value if two atoms are in the maximal entangled state, or vice versa.     

硅胶固定功能化离子液体的制备及其在HMF合成中的应用

通过氯丙基三甲氧基硅烷将磺基功能化离子液体--N-磺丙基咪唑盐化学键联到微球硅胶上,制得微球硅胶固定化离子液体（IL3）。用FTIR、TG、13C-NMR、SEM、BET及酸度测定等方法对IL3进行了表征,并考察其在果糖脱水合成5-羟甲基糠醛（HMF）过程中的催化性能。研究结果表明：氯丙基三甲氧基硅烷可以将磺基功能化咪唑型离子液体化学键联到微球硅胶上。微球硅胶固定化磺基咪唑离子液体能有效催化果糖脱水生成HMF。在45.4-IL3催化下、乙二醇甲醚(EGME)溶剂中、115℃反应5小时, HMF收率可达82.1％。使用后的催化剂可以方便地循环使用。但随次数增加,HMF收率明显下降。45.4-IL3催化剂循环使用四次后,HMF的收率下降为53.0%。     

Entanglement reciprocation between two charge qubits and two-cavity field

We propose a simple scheme to generate two-mode entangled coherent state in two separated cavities and realize the entanglement reciprocation between the superconducting charge qubits and continuous-variable system. By measuring the state of charge qubits, we find that the entanglement of two charge qubits, which are initially prepared in the maximally entangled state, can be transferred to the two-cavity field, and at this time the two-cavity field is in the entangled coherent state. We also find that the entanglement can be retrieved back to the two charge qubits after measuring the state of the two-cavity field.