稀土镧在腈纶纤维化学镀银中的应用及其电化学性能

采用化学镀法(镀液中加入适量的稀土镧)在硅烷偶联剂改性后的腈纶纤维表面沉积金属银,由粒径分析、X射线衍射、扫描电子显微镜、阴极极化曲线以及循环伏安曲线等方法对其进行表征,研究了硝酸镧对化学镀银沉积速度、镀层质量和电化学性能的影响。结果表明,镀银液中加入适宜的硝酸镧,银的沉积速率和腈纶纤维表面银镀层的表面质量均有不同程度的提高。电化学测试表明,镀银液中增大硝酸镧的浓度(0～0.01 g/L),阴极极化曲线极化度增大,氧化还原峰的电流上升,电沉积的速度加快。     

Cyclodextrin‐Templated Porphyrin Nanorings

α‐ and β‐Cyclodextrins have been used as scaffolds for the synthesis of six‐ and seven‐legged templates by functionalizing every primary CH₂OH with a 4‐pyridyl moiety. Although these templates are flexible, they are very effective for directing the synthesis of macrocyclic porphyrin oligomers consisting of six or seven porphyrin units. The transfer of chirality from the cyclodextrin templates to their nanoring hosts is evident from NMR and circular dichroism spectroscopy. Surprisingly, the mean effective molarity for binding the flexible α‐cyclodextrin‐based template within the six‐porphyrin nanoring (74 M ) is almost as high as for the previously studied rigid hexadentate template (180 M ). The discovery that flexible templates are effective in this system, and the availability of a template with a prime number of binding sites, open up many possibilities for the template‐directed synthesis of larger macrocycles.     

Weak acid–base interaction induced assembly for the formation of rambutan-like poly(styrene-alt-maleic anhydride)/silica composite microspheres

To investigate the effect of surface functionality on the morphology of polymer/silica composite, poly(styrene-alt-maleic anhydride) (SMA) spheres prepared via precipitation polymerization method was employed. In water/ethanol solution, diethanolamine (DEA) was used to catalyze the hydrolysis reaction of tetraethoxysilane (TEOS), and rambutan-like poly(styrene-alt-maleic anhydride)/silica (SMA/SiO₂) microspheres were synthesized through in situ sol–gel process. The obtained structure and morphology were characterized by FTIR, NMR, TEM, SEM, and TGA. The results showed that the hydrolyzed SMA chains on the surface was crucial to the nucleation and growth of silica, and the morphologies of SMA/SiO₂ composite microspheres can be controlled by the amount of DEA and the ratio of SMA/TEOS. In addition, the SMA/SiO₂ microspheres were used to prepare hierarchical structure of SMA/SiO₂/Ag particles, which were utilized for the construction of surface-enhanced Raman scattering substrate (SERS).     

A Hydrolytically Stable Vanadium(IV) Metal–Organic Framework with Photocatalytic Bacteriostatic Activity for Autonomous Indoor Humidity Control

Metal–organic frameworks (MOFs) with long-term stability and reversible high water uptake properties can be ideal candidates for water harvesting and indoor humidity control. Now, a mesoporous and highly stable MOF, BIT-66 is presented that has indoor humidity control capability and a photocatalytic bacteriostatic effect. BIT-66 (V₃(O)₃(H₂O)(BTB)₂), possesses prominent moisture tunability in the range of 45–60 % RH and a water uptake and working capacity of 71 and 55 wt %, respectively, showing good recyclability and excellent performance in water adsorption–desorption cycles. Importantly, this MOF demonstrates a unique photocatalytic bacteriostatic behavior under visible light, which can effectively ameliorate the bacteria and/or mold breeding problem in water adsorbing materials.     

A Hydrolytically Stable Vanadium(IV) Metal–Organic Framework with Photocatalytic Bacteriostatic Activity for Autonomous Indoor Humidity Control

Metal–organic frameworks (MOFs) with long‐term stability and reversible high water uptake properties can be ideal candidates for water harvesting and indoor humidity control. Now, a mesoporous and highly stable MOF, BIT‐66 is presented that has indoor humidity control capability and a photocatalytic bacteriostatic effect. BIT‐66 (V₃(O)₃(H₂O)(BTB)₂), possesses prominent moisture tunability in the range of 45–60 % RH and a water uptake and working capacity of 71 and 55 wt %, respectively, showing good recyclability and excellent performance in water adsorption–desorption cycles. Importantly, this MOF demonstrates a unique photocatalytic bacteriostatic behavior under visible light, which can effectively ameliorate the bacteria and/or mold breeding problem in water adsorbing materials.     

基于交流调制技术的弱电流放大器研制

在射线强度测量中,积分电离室输出的电流信号在10–10～10–15 A范围内,该弱电流信号需要转换和放大才可以进行采集.针对积分电离室本文设计了一种弱电流信号放大系统,采用交流调制技术将待测弱直流电流信号调制为交流电压信号,再经放大、相敏检波、滤波等电路处理后得到直流电压信号,最后进行数据采集;同时在系统中引入直流负反...     

二维纳米材料的改性及其环境污染物治理方面的应用

二维纳米材料是一类具有类似二维平面形态,且厚度在纳米级甚至数个原子层的材料,其种类繁多并且具有很多与体相材料不同的物化性质,在众多领域受到了广泛关注。二维纳米材料在催化降解、吸脱附、过滤、传感检测等领域具有可观的应用潜力,还可用于环境污染的防治。通过形貌、元素、基团、缺陷的修饰、改性和材料合成等策略可以调控二维纳米材料的性质,从而研发新的材料体系或者改善二维纳米材料的性能。本文首先归纳了二维纳米材料的种类,并重点阐述了各种改性策略的作用及研究现状,以及改性的二维纳米材料在治理水体污染、大气污染和污染物检测等方面的应用,为二维纳米材料在环境治理领域的发展现状作了系统介绍和展望。     

纵向数据下非参数带测量误差的部分线性变系数模型的估计

本文研究纵向数据下非参数部分带有测量误差的部分线性变系数模型的估计.利用B样条函数近似模型中的变系数函数,构造偏差修正的二次推断函数,得到模型中未知参数和变系数函数的估计.证明变系数函数估计量的相合性和参数估计量的渐近正态性.数值模拟和实例分析结果表明所提估计方法在有限样本下的有效性.     

Regulating Phase Junction and Oxygen Vacancies of TiO2 Nanoarrays for Boosted Photoelectrochemical Water Oxidation

In this study, we have provided a facile solution to synthesize well-aligned titanium dioxide nanorods by using hydrothermal reaction. By calcining the materials under different atmospheres and temperatures, a batch of titanium dioxides with excellent oxygen evolution reaction(OER) catalytic efficiency were obtained. This new structured TiO₂ photoanode material yields a high photocurrent density of 5.69 mA/cm² at 1.23 V vs. reversible hydrogen electrode(RHE) under simulated solar light(100 mW/cm²). Surface photovoltage techniques and other measurements were carried out to confirm that the enhanced photoelectrochemical performances were attributed to the synergistic effect of the phase junction and a certain content of surface states, which accelerate the separation and transmission of the photogenerated charges. This material with phase junction and surface states promises a potential application in the field of photoelectric catalysis under solar light.     

A 1D/2D Helical CdS/ZnIn2S4 Nano‐Heterostructure

Multidimensional nano‐heterostructures (NHSs) that have unique dimensionality‐dependent integrative and synergic effects are intriguing but still underdeveloped. Here, we report the first helical 1D/2D epitaxial NHS between CdS and ZnIn₂S₄. Experimental and theoretical studies reveal that the mismatches in lattice and dangling bonds between 1D and 2D units govern the growth procedure. The resulting well‐defined interface induces the delocalized interface states, thus facilitate the charge transfer and enhance the performance in the photoelectrochemical cells. We foresee that the mechanistic insights gained and the electronic structures revealed would inspire the design of more complex 1D/2D NHSs with outstanding functionalities.