Molten-salt Synthesis and Properties of ZnS with Hexagonal Prism Morphology

ZnS with hexagonal prism morphology has been synthesized successfully by molten-salt method with ZnS nanoparticles as precursors, and the ZnS nanoparticles were prepared by one-step solid-state reaction of Zn（CH3COO）2·2H2O with Na2S·9H2O at ambient temperature. Crystal structure and morphology of the product were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and HRTEM. Ultraviolet-visible optical absorption spectrum of the ZnS hexagonal prism shows a distinct red shift from that of bulk ZnS crystals and photoluminescence spectrum exhibits strong emissions at 380 and 500 nm, respectively. Further experiments were designed and the formation mechanism of the ZnS hexagonal prism has been also discussed in brief.     

牛油果中化学成分的内部萃取电喷雾电离质谱检测

采用内部萃取电喷雾电离质谱(iEESI-MS)技术,以甲醇作为萃取溶剂,无需样品预处理,在优化条件下分别对牛油果果肉和果皮中化学成分进行快速直接鉴定,并考察了不同成熟度牛油果果肉中化学成分的差异.实验结果表明,在负离子检测模式下,从果肉中鉴定出棕榈酸、硬脂酸、棕榈油酸、油酸和亚麻酸等12种有效营养成分,从果皮中鉴定出儿茶素、绿原酸等11种营养成分.利用正交偏最小二乘判别分析法(OPLS-DA)对不同成熟度的牛油果果肉的iEESI-MS指纹谱图数据进行分析发现,此方法能够有效判别不同成熟程度的牛油果且5种化学成分差异显著.本方法无需样品预处理、样品耗量少、分析速度快(单个样品检测时间小于1 min)且操作简便,为植物有效营养成分和医用价值的开发提供了一种快速质谱分析新方法.     

油茶果壳活性炭的制备及其对Cr(Ⅵ)的去除

利用磷酸活化法制备油茶果壳活性炭,并将其作为吸附剂用于去除水溶液中的Cr(Ⅵ),同时探讨了不同参数(Cr(Ⅵ)的初始浓度、吸附剂的用量、pH、温度等)对油茶果壳活性炭吸附Cr(Ⅵ)的影响。结果表明:当温度为293 K,Cr(Ⅵ)初始浓度为250 mg/L,pH为2.0时,Cr(Ⅵ)的最大吸附量可达165.0 mg/L。根据吸附动力学原理,发现其吸附过程遵循拟二级动力学模型。Cr(Ⅵ)的去除程度随Cr(Ⅵ)初始浓度的升高而增加,且其平衡数据与Freundlich模型拟合良好。     

聚芳醚酮在溶液中的分子构象与分子极化

经从头计算,得到4,4'-二氟苯酮二面角为44°,MES₃二面角为51°;用UV光谱法研究了单分散齐聚物在H₂SO₄中的分子构象与极化,结果表明:H₂SO₄使碳基质子化是产生极化的主要因素之一,由此产生的新吸收峰在λ=400nm左右;极化作用产生的平面构象经重叠后在λ=500nm左右产生另一新的吸收峰.由质子化模型并考虑组态相互作用的计算结果与文献一致.证明了聚芳醚酮高聚物在H₂SO₄中,于400nm左右处产生的峰(UV)为羰基极化的结果,指明在H₂SO₄中测其分子量时应按羰基含量校正.     

一种直流力矩电机系统的滞滑摩擦补偿方法

陀螺漂移测试转台直流力矩电机系统中存在的非线性滞滑摩擦，使转台在PID控制下存在滞滑极限环。为提高转台定位精度，应用具有滞滑(stick-slip)摩擦的直流力矩电机系统模型，推导了一种补偿方法，对含有滞滑摩擦的PID控制转台直流力矩电机伺服系统进行滞滑摩擦补偿。在采用PID控制的转台电机系统定位工作状态下，这种滞滑补偿方法可以减小滞滑极限环的幅值。仿真结果证明了该补偿方法的有效性。     

六顶角带谱参数杨-Baxter方程的解

通过五个解交换,四组非退化基本解和七组退化解,给出了精确可解统计模型理论中六顶角带谱参数杨-Baxter方程的全部解.并讨论了解的幺正条件. 关键词：     

An Underlying Symmetry Determines all Elements of CKM and PMNS up to a Universal Constant?

Observing the CKM matrix elements written in different parametrization schemes, one can notice obvious relations among the sine-values of the CP phases in those schemes. Using the relations, we establish a few parametrization-independent equations, by which the matrix elements of the CKM matrix can be completely fixed up to a universal parameter. If it is true, we expect that there should exist a hidden symmetry in the nature, which determines the relations. Moreover, it requires a universal parameter, naturally it would be the famous Jarlskog invariant, which is also parametrization independent. Thus the four parameters (three mixing angles and one CP phase) of the CKM matrix are not free, but determined by the symmetry and the universal parameter. As we generalize the rules to the PMNS matrix for neutrino mixing, the CP phase of the lepton sector is predicted to be within a range of 0~59° centered at 39° (in the P_a parametrization) which will be tested in the future experiments.     

Hawking radiation as tunneling and the unified first law of thermodynamics at the apparent horizon of the FRW universe

Relations between the tunneling rate FRW universe are investigated. The namics in such a dynamical system. first law of thermodynamics through and the unified first law of thermodynamics at the apparent horizon of the tunneling rate arises as a consequence of the unified first law of thermodyAnalysis shows how the tunneling is intimately connected with the unified the principle of conservation of energy.     

化学特征指纹技术在溢油鉴别研究的应用进展

从模糊聚类分析法、油指纹配比法、主要物质分析法等方面介绍了化学特征指纹图谱技术在鉴别溢油源研究方面的进展。