The self-assemblies of a newly designed star-shaped molecule end-capped with bromine atoms studied by scanning tunneling microscopy

A new star-shaped molecule StOF-Br_3 containing oligofluorenes and halogen atoms(Bromine) has been synthesized and studied by Scanning Tunneling Microscopy(STM) at the highly oriented pyrolytic graphite(HOPG) surface.We have obtained the high-resolution self-assembled STM images,from which the highly ordered and closely packed non-porous arrangements of the StOF-Br_3 molecular selfassemblies at the heptanoic acid/HOPG surface could be observed.The molecular models and selfassembled StOF-Br_3 architectures have been given in the following text.Besides,we have also figured out the surface free energy by the density functional theory(DFT) calculation,which proved that the halogen...halogen interaction was strong enough to stabilize the ordered molecular self-assemblies.This work verifies the existence of bromine...bromine interactions,and meanwhile provides a kind of effective approach for quickly building ordered molecular nanoarchitectures with large areas and different geometries.     

玻色化方法在超对称可积系统的应用

利用玻色化方法可以避免超对称可积系统中反对易费米场带来的计算困难. 本文以N=1超对称mKdVB系统为例, 利用玻色化方法, 将其转化为只有玻色场的耦合系统. 应用标准的WTC方法, 证明了该耦合系统具有Painlevé性质. 运用Painlevé截断方法, 可以得到玻色化后超对称mKdVB系统的非局域对称. 为了求解与非局域对称相关的Lie第一性原理, 引入新的场将玻色化后系统拓展为更大的系统. 通过引入新的场, 该非局域对称局域化为Lie点对称. 因此, 可以利用Lie点对称约化方法研究拓展后的系统, 得到超对称mKdVB系统的孤子与其他孤波相互作用解.     

Lump and interaction solutions to the (3+1)-dimensional Burgers equation

The(3+1)-dimensional Burgers equation, which describes nonlinear waves in turbulence and the interface dynamics,is considered. Two types of semi-rational solutions, namely, the lump–kink solution and the lump–two kinks solution, are constructed from the quadratic function ansatz. Some interesting features of interactions between lumps and other solitons are revealed analytically and shown graphically, such as fusion and fission processes.     

基于CARS技术的超燃冲压发动机点火过程温度测量

相干anti-Stokes Raman散射（coherent anti-Stokes Raman scattering，CARS）技术作为一种非接触测量手段，已广泛应用于多种发动机模型燃烧室温度测量及地面试验.然而，目前的工作主要集中在稳态燃烧场温度的测量，缺乏用高分辨率的单脉冲来测量瞬变的燃烧火焰温度及组分浓度的研究.基于CARS理论，结合多参数拟合算法，开发了基于MATLAB的CARS光谱计算和拟合程序CARSCF；利用McKenna平面火焰炉在不同工况下进行了温度测量，并与DLR测量结果进行对比，结果显示开发的CARSCF具有较高的测量重复性和准确性；最后将CARS技术应用于测量超燃冲压发动机点火过程中的温度测量，获取了点火过程中的温度.结果显示，在来流Mach数为3的条件下，H₂/air点火过程中温度呈现急剧上升然后缓慢下降，而CARS信号则呈现急剧上升然后急剧下降随后又缓慢上升的趋势，并且在点火过程中最高温度为1 511 K.      

High sensitivity conductivity-temperature-depth sensing based on an optical microfiber coupler combined fiber loop

In order to meet the practical needs of all-fiber conductivity-temperature-depth sensors with high sensitivity,compact structure,and easy packaging,this Letter uses a microfiber coupler combined with fiber loop(MCFL)reflective photonic device to conduct salinity,temperature,and deep sensing experiments.These MCFLs’dynamic range and resolution of salinity,temperature,and depth can meet the requirements of actual marine environment monitoring.This structure opens up a new design idea for the practical research of microfiber coupler-based marine environmental parameter sensors.     

高效液相色谱-荧光检测器法测定2-噁唑烷酮的含量

建立一种利用高效液相色谱结合荧光检测器准确测定2-噁唑烷酮含量的方法。样品中的2-噁唑烷酮和占吨氢醇在60℃的条件下衍生70 min后,直接进样分析。采用月旭XB-C18色谱柱,流动相为0.02 mol/L乙酸钠水溶液和乙腈,检测器波长为λex=213 nm,λem=308 nm,流速1.0 mL/min,柱温35℃的条件下。2-噁唑烷酮浓度在0.5~50.0mg/mL时,线性关系良好(R2=0.9995),检测限和定量限分别为0.005 mg/L、0.016 mg/L。该方法准确、灵敏、快速,适用于2-噁唑烷酮含量的检测。     

高效液相色谱法测定烯草酮合成废液中4-二甲氨基吡啶含量

采用高效液相色谱法测定烯草酮合成废液中4-二甲氨基吡啶含量,使用BDS Hypersil C18不锈钢柱(250mm×4.6mm),以甲醇∶水∶磷酸=60∶39.75∶0.25为流动相,使用紫外检测器,在波长254nm下进行测定。实验测定4-二甲氨基吡啶加标回收率为97.7%,变异系数为3.33%,线性相关系数为0.9994。     

(3S,4S)-4-氨基-3-羟基-6-甲基庚酸的合成

价廉易得的L-亮氨酸先以苄基同时保护氨基及羧基得(S)-2-(二苄胺基)-4-甲基戊酸苄酯,进而在碱性条件下与乙腈发生亲核取代反应得(S)-4-(二苄胺基)-6-甲基-3-氧代庚腈,再经硼氢化钠选择性还原羰基得(3S,4S)-4-(二苄胺基)-3-羟基-6-甲基庚腈,用双氧水氧化得(3S,4S)-4-(二苄胺基)-3-羟基-6-甲基庚酸,最后在Pd(OH)2/C-H2作用下脱掉苄基得到(3S,4S)-4-氨基-3-羟基-6-甲基庚酸,即(3S,4S)-statine。整个合成路线总产率为33.6%。