Studies on the Phase Behavior of Beta‐cypermethrion Microemulsion

The phase behavior of the system of surfactant SAA [0203B, nonionic surfactant 700# and methanol (weight ratio=6∶1∶1)]/mixed oil [beta‐cypermethrion, dimethyl benzene and cyclohexanone (weight ratio=2∶2∶1,or 0∶2∶1)]/water [distilled water (0 mg/L), or standard water (342 mg/L), or ultra‐hard water (500 mg/L)] has been studied in a pseudoternary phase diagram at 25 ± 1°C. Our results indicated that the isotropic monophasic area in the phase diagrams decreased significantly as the beta‐cypermethrion was added in the oil phase. In an attempt to the microemulsion electrical condectivity can be define regions corresponding to three structure states W/O, B.C., and O/W type in the microemulsion domain. The influence of beta‐cypermethrion on their regions sequences B.C. > O/W?W/O type. This work will be beneficial to improving the quality of beta‐cypermethrion microemulsion and make it more competitive in the market.     

Biomimetically inspired total synthesis of (12S)-12-hydroxymonocerin and (12R)-12-hydroxymonocerin

A concise asymmetric total synthesis of (12S)-12-hydroxymonocerin (1) and (12R)-12-hydroxymonocerin (2) were efficiently achieved from the known 4-bromo-2,6-dimethoxyphenol. The synthetic approach was inspired by our biomimetic synthesis of (+)-monocerin (3) and 7-O-demethylmonocerin (4). The cis-fused furobenzopyranones of 1 and 2 was efficiently constructed via an intramolecular nucleophilic trapping of a quinonemethide intermediate, which was obtained by benzylic oxidation of compound 10 using 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ).     

Cytotoxic Diterpenoids from the Stem Bark of Annona squamosa L.

Three new ent‐kaurane diterpenoids, (4α)‐19‐nor‐ent‐kaurane‐4,16,17‐triol ( 1 ), (4α,16α)‐17‐(acetyloxy)‐19‐nor‐ent‐kaurane‐4,16‐diol ( 2 ), and 17‐hydroxy‐ent‐kaur‐15‐en‐19‐al ( 3 ), together with 11 known compounds, were isolated from the stem bark of Annona squamosa L. The structures of 1 – 3 were identified by analysis of their spectroscopic data. All compounds were evaluated for cytotoxic activity against human lung cancer (95‐D) and ovarian cancer (A2780) cell lines, and compounds 3, 5, 7, 11 – 14 exhibited promising antiproliferative activities with IC₅₀ values ranging from 0.38 to 34.66 μM .     

基于Rydberg原子天线的太赫兹测量

Rydberg原子在微波和太赫兹频段具有极大的电偶极矩,利用量子干涉效应可实现对该频段电磁波场强的高灵敏探测,理论上灵敏度可达到远高于现有探测技术的水平.基于Rydberg原子量子效应的电磁场探测及精密测量技术在太赫兹的场强和功率计量、太赫兹通信和太赫兹成像等方面有着巨大的应用前景.本文回顾了基于Rydberg原子量子干涉效应实现电磁波电场自校准和可溯源测量的基本理论和实验技术,详细介绍了基于Rydberg原子的高灵敏太赫兹场强测量、太赫兹近场高速成像和太赫兹数字通信的基本原理和技术方案.最后简单介绍了本研究团队正在开展的基于Rydberg原子的太赫兹探测工作.     

Left–right asymmetry in semi-inclusive deep inelastic scattering process

We analyze the left–right asymmetry of pion production in semi-inclusive deep inelastic scattering (SIDIS) process of unpolarized charged lepton on transversely polarized nucleon target. Unlike available treatments, in which some specific weighting functions are multiplied to separate theoretically motivated quantities, we do not introduce any weighting function following the analyzing method by the E704 experiment. The advantage is that this basic observable is free of any theoretical bias, although we can perform the calculation under the current theoretical framework. We present numerical calculations at both HERMES kinematics for the proton target and JLab kinematics for the neutron target. We find that with the current theoretical understanding, Sivers effect plays a key role in our analysis.     

Modeling and dynamic analysis of bolted joined cylindrical shell

Based on Sanders shell theory, modeling and dynamic analysis of bolted joined cylindrical shell were studied in this paper. When subjected to external excitations, contact state such as stick, slip and separation may occur at those locations of bolts. Considering these three contact states, an analytical model of cylindrical shell with a piecewise-linear boundary was established for the bolted joined cylindrical shell. First, the model was verified by the simplified line system, and the effects of stiffness in connecting interface and the number of bolts on natural frequency and mode shape were investigated. Then, through the response under instantaneous excitation, damping characteristic of the system was proved which is caused by the friction model. Last, the effects of external load frequency, response location, excitation amplitude and connecting parameters including stiffness and preload were numerically investigated and fully explained by 3-D frequency spectrum. The results indicated that periodic motion, times periodic motion and even chaotic motion were observed based on different parameters.     

锗烯在金属衬底上的结构及电子性质的第一性原理研究

基于密度泛函理论的第一性原理计算,我们系统的研究了锗烯在Pt(111)、Au(111)和Al(111)表面的几何和电子结构.在这三种金属衬底上寻找到了9种结构,其中Al(111)-a、Au(111)-b和Pt(111)-c结构就是目前实验上已经成功制备的结构.我们还发现了其余6种目前理论和实验均没有提出,此外,Al(111)-b、Au(111)-a和Pt(111)-b结构的Dirac态仍保留,这些结构的形成能均大于范德瓦尔斯作用,因此非常有希望在实验上制备出来,应用于量子自旋霍尔效应的研究.本文的研究为锗烯在半导体衬底上的制备及应用奠定了理论基础.