Microscopic multi-point temperature sensing based on microfiber double-knot resonators

A novel fiber-optic sensor structure fabricated by cascading two optical microfiber knot resonators (MKRs) is proposed and demonstrated in this paper. A theoretical model for describing the principle of the sensing structure is given and its temperature responses are characterized experimentally. Experimental results show that high-precision and simultaneous multi-point temperature sensing in micro-scale can be achieved. Such a sensing structure also has the potential for achieving dual-parameter measurement to eliminate the cross-talk between two parameters in micro-scale.     

Numerical simulation of indoor suspension particles based on v-f model

This paper presents a new algorithm for the prediction of indoor suspension particle dispersion based on a v²-f model. In order to handle the near-wall turbulence anisotropy properly, which is significant in the dispersion of fine particles, the particle eddy diffusivity is calculated using different formulae among regions of the turbulent core and in the vicinity of walls. The new algorithm is validated by several cases performed in two ventilated rooms with various air distribution patterns. The simulation results reveal that v²-f nonlinear turbulence model combined with a particle convective equation gives satisfactory agreement with the experimental data. It is generally found that the dynamic equation combined with the v²-f model can properly handle low Reynolds number (LRN) flows which are usually encountered in indoor air flows and fine particle dispersion.     

氦气提纯技术发展现状与应用分析

为实现氦气资源的循环利用,有必要对氦气进行回收纯化。文中对目前国内外氦气的提纯技术发展现状进行了分析介绍,并综合分析比较了这些方法的应用原理、优缺点及发展趋势,针对各自的使用特点,给出了几种详细的提纯工艺实现方法,为促进我国氦气提纯技术的发展提供了新的思路。     

Optimizing Optoelectronic Properties of Pyrimidine‐Based TADF Emitters by Changing the Substituent for Organic Light‐Emitting Diodes with External Quantum Efficiency Close to 25 % and Slow Efficiency Roll‐Off

A series of green butterfly‐shaped thermally activated delayed fluorescence (TADF) emitters, namely PXZPM , PXZMePM , and PXZPhPM , are developed by integrating an electron‐donor (D) phenoxazine unit and electron‐acceptor (A) 2‐substituted pyrimidine moiety into one molecule via a phenyl‐bridge π linkage to form a D –π–A–π–D configuration. Changing the substituent at pyrimidine unit in these emitters can finely tune their emissive characteristics, thermal properties, and energy gaps between the singlet and triplet states while maintaining frontier molecular orbital levels, and thereby optimizing their optoelectronic properties. Employing these TADF emitters results in a green fluorescent organic light‐emitting diode (OLED) that exhibits a peak forward‐viewing external quantum efficiency (EQE) close to 25 % and a slow efficiency roll‐off characteristic at high luminance.     

方便面中砷元素的形态分析

建立了硝酸提取,高效液相色谱一原子荧光联用技术测定方便面中不同砷形态的分析方法。样品经0．15mol／L盐酸溶液超声提取后离心过滤,上机测试。实验表明：砷的4种形态亚砷酸[As（Ⅲ）]、砷酸[As（V）]、一甲基胂酸（MMA）和二甲基胂酸（DMA）的线性范围为0-50μg／L,相关系数（r）均优于0．9990,检出限在2～8μg／L之间,砷各形态的测量重复性（以RSD表示）均小于5％,样品的加标回收率为78％-118％。同时用原子荧光光度计检测了样品中总砷,并将两种方法测定结果进行了对比,结果符合理论以及文献报道。该方法操作简单快速、结果准确可靠,适用于方便面中砷形态的分析测定。     

Influence of insertion of a noble gas atom on halogen bonding in H2O···XCCNgF and H3N···XCCNgF (X = Cl and Br; Ng = Ar, Kr, and Xe) complexes

The H₂O···XCCNgF and H₃N···XCCNgF (X = Cl and Br; Ng = Ar, Kr, and Xe) complexes have been studied with quantum chemical calculations at the MP2/aug-cc-pVTZ level. The results show that the inserted noble gas atom has an enhancing effect on the strength of halogen bond, and this enhancement is weakened with the increase of noble gas atomic number. The methyl and Li substituents in the electron donor strengthen the halogen bond. The interaction energy increases from ?3.75 kcal/mol in H₃N–BrCCF complex to ?9.66 kcal/mol in H₂LiN–BrCCArF complex. These complexes have been analyzed with atoms in molecules, natural bond orbital, molecular electrostatic potentials, and energy decomposition calculations.