基于偶联反应新极谱法测定痕量亚硝酸根的研究——Ⅱ.以苯酚为偶联试剂

本文研究了苯酚在氨性缓冲溶液中与NO_2~--磺胺重氮盐偶联反应的实验条件,建立了一个灵敏快速测定痕量NO_2~-的新方法。NO_2~-离子浓度在1.0×10~(-10)～4.8×10~(-7)g/ml范围内,与峰高呈良好的线性关系.4000倍量NO_3~-存在不干扰.     

Nanowire plasmonic waveguides,circuits and devices

As typical one‐dimensional nanostructures for waveguiding tightly confined optical fields beyond the diffraction limit, metal nanowires have been used as versatile nanoscale building blocks for functional plasmonic and photonic structures and devices. Metal nanowires, especially those fabricated by bottom‐up synthesis such as Ag and Au nanowires, usually exhibit excellent diameter uniformity and surface smoothness with diameters down to tens of nanometers, which offers great opportunities for plasmonic waveguiding of optical fields with deep‐subwavelength confinement, coherence maintenance and low scattering losses. Based on nanowire plasmonic waveguides, a variety of applications ranging from plasmonic couplers, interferometers, resonators to photon emitters have been reported in recent years. In this article, significant progresses in these nanowire plasmonic waveguides, circuits and devices are reviewed. Future outlook and challenges are also discussed.     

A novel polypropylene composite filled by kaolin particles with β-nucleation

Kaolin-filled polypropylene (PP) composites generally form α-crystal due to the effect of kaolin with α-nucleation. The transition from α- to β-nucleation of kaolin has been investigated, and a novel kaolin with β-nucleation (β-kaolin) and kaolin-filled PP composites with high β-crystal content were prepared first. The DSC and WAXD results indicated that the β-kaolin exhibits stronger β-nucleating ability than CaPA as β-nucleating agent for PP crystallization. It is found that the β-crystal content has been influenced little by filler contents in β-kaolin-filled PP composites. Mechanical properties and spherulitic morphology of filled PP composites was characterized. The synergistic effect of filler and β-crystal significantly improved impact strength of kaolin-filled PP composites.

     

Engineering the Band Gap States of the Rutile TiO2(110) Surface by Modulating the Active Heteroatom

Introducing band gap states to TiO₂ photocatalysts is an efficient strategy for expanding the range of accessible energy available in the solar spectrum. However, few approaches are able to introduce band gap states and improve photocatalytic performance simultaneously. Introducing band gap states by creating surface disorder can incapacitate reactivity where unambiguous adsorption sites are a prerequisite. An alternative method for introduction of band gap states is demonstrated in which selected heteroatoms are implanted at preferred surface sites. Theoretical prediction and experimental verification reveal that the implanted heteroatoms not only introduce band gap states without creating surface disorder, but also function as active sites for the Cr^VI reduction reaction. This promising approach may be applicable to the surfaces of other solar harvesting materials where engineered band gap states could be used to tune photophysical and ‐catalytic properties.     

液相色谱-串联质谱法测定海参和海胆中的单唾液酸神经节苷脂

建立了液相色谱-四极杆串联质谱法定量检测海参和海胆中单唾液酸神经节苷脂的分析方法。采用Svennerholm法从海胆或海参样品中提取神经节苷脂,经C8固相萃取柱净化,采用APS-2 NH₂柱(150 mm×2.1 mm, 3 μm),以乙腈和50 mmol/L乙酸铵溶液(pH 5.6)为流动相,梯度洗脱。样品中每种成分的定量在多反应监测模式下进行。该方法具有极高的灵敏度,定量限可低至纳克级。非硫酸酯化单唾液酸神经节苷脂(NMG)和硫酸酯化单唾液酸神经节苷脂(SMG)在1～40 ng进样量范围内呈现良好的线性关系;定量结果显示所测海参样品中美国红参的NMG含量最高,海胆样品中紫海胆的SMG含量最高;海胆中总的单唾液酸神经节苷脂含量(4.30～6.40 mg/g)明显高于各海参样品(8～131 μg/g)。该方法稳定可靠,适合海胆和海参中微量单唾液酸神经节苷脂的定量分析。     

In situ synchrotron X‐ray diffraction analysis of deformation behaviour in Ti–Ni‐based thin films

Deformation mechanisms of as‐deposited and post‐annealed Ti_50.2Ni_49.6, Ti_50.3Ni_46.2Cu_3.5 and Ti_48.5Ni_40.8Cu_7.5 thin films were investigated using the in situ synchrotron X‐ray diffraction technique. Results showed that initial crystalline phases determined the deformation mechanisms of all the films during tensile loading. For the films dominated by monoclinic martensites (B19′), tensile stress induced the detwinning of 〈011〉 type‐II twins and resulted in the preferred orientations of (002)_B19′ parallel to the loading direction (∥ LD) and (020)_B19′ perpendicular to the LD (⊥ LD). For the films dominated by austenite (B2), the austenite directly transformed into martensitic variants (B19′) with preferred orientations of (002)_B19′ ∥ LD and (020)_B19′ ⊥ LD. For the Ti_50.3Ni_46.2Cu_3.5 and Ti_48.1Ni_40.8Cu_7.5 films, martensitic transformation temperatures decreased apparently after post‐annealing because of the large thermal stress generated in the films due to the large differences in thermal expansion coefficients between the film and substrate.     

Development of formamidinium lead iodide-based perovskite solar cells: efficiency and stability

Perovskite materials have been particularly eye-catching by virtue of their excellent properties such as high light absorption coefficient, long carrier lifetime, low exciton binding energy and ambipolar transmission (perovskites have the characteristics of transporting both electrons and holes). Limited by the wider band gap (1.55 eV), worse thermal stability and more defect states, the first widely used methylammonium lead iodide has been gradually replaced by formamidinium lead iodide (FAPbI₃) with a narrower band gap of 1.48 eV and better thermal stability. However, FAPbI₃ is stabilized as the yellow non-perovskite active phase at low temperatures, and the required black phase (α-FAPbI₃) can only be obtained at high temperatures. In this perspective, we summarize the current efforts to stabilize α-FAPbI₃, and propose that pure α-FAPbI₃ is an ideal material for single-junction cells, and a triple-layer mesoporous architecture could help to stabilize pure α-FAPbI₃. Furthermore, reducing the band gap and using tandem solar cells may ulteriorly approach the Shockley–Queisser limit efficiency. We also make a prospect that the enhancement of industrial applications as well as the lifetime of devices may help achieve commercialization of PSCs in the future.

This perspective is focused on the current development state and the future development direction of FA-based perovskite materials and solar cells.     

玻炭汞膜电极多阶半微分溶出曲线的理论方程式

本文建立了汞膜电极阳极溶出多阶半微分电分析法理论的基本数学模型,借助电子计算机,直接描绘出其理论曲线,并给出有关特征参数,计算结果与实验验证表明,本文所推导的理论曲线方程式是正确的。     

Restricted 2-factor polytopes

The optimal k-restricted 2-factor problem consists of finding, in a complete undirected graph K _n , a minimum cost 2-factor (subgraph having degree 2 at every node) with all components having more than k nodes. The problem is a relaxation of the well-known symmetric travelling salesman problem, and is equivalent to it when ≤k≤n−1. We study the k-restricted 2-factor polytope. We present a large class of valid inequalities, called bipartition inequalities, and describe some of their properties; some of these results are new even for the travelling salesman polytope. For the case k=3, the triangle-free 2-factor polytope, we derive a necessary and sufficient condition for such inequalities to be facet inducing. Received March 4, 1997 / Revised version received September 7, 1998?Published online November 9, 1999     

全固态介观太阳能电池:从染料敏化到钙钛矿

介观太阳能电池(Mesoscopic Solar Cells)作为新一代太阳能电池的突出代表, 具有原材料来源丰富, 制备工艺简单, 光电转换效率高等优点, 从而具有广阔的应用前景. 本工作简要评述了全固态介观太阳能电池从染料敏化太阳能电池(Dye-sensitized solar cells)发展到钙钛矿太阳能电池(Perovskite solar cells)过程中新材料、新技术和新概念的研究进展. 1998年, Grätzel课题组首次将固态有机空穴传输材料spiro-OMeTAD应用到染料敏化太阳能电池中, 制备出全固态染料敏化太阳能电池, 虽然仅获得了0.74%的光电转换效率, 但是却使得全固态染料敏化太阳能电池迅速发展成为介观太阳能电池的重要研究方向. 2012年, Park与Grätzel课题组合作, 使用钙钛矿型吸光材料(CH₃NH₃)PbI₃作为敏化剂, spiro-OMeTAD作为空穴收集层, 制备出光电转换效率达到9.7%的全固态介观太阳能电池, 又被称为钙钛矿太阳能电池. 自此, 基于钙钛矿材料的介观太阳能电池迅速成为太阳能电池领域的研究热点. 目前, 钙钛矿太阳能电池的最高公证效率已经达到20.1%. 钙钛矿太阳能电池作为介观太阳能电池商业化道路上里程碑式的突破, 在材料开发、界面优化以及器件稳定性方面的研究仍充满挑战, 也期待新的突破.