基于一种新型聚噻吩衍生物为给体的非富勒烯聚合物太阳能电池

With the development of non-fullerene small-molecule acceptors, non-fullerene polymer solar cells (PSCs) have garnered increased attention due to their high performance. While photons are absorbed and converted to free charge carriers in the active layer, the donor and acceptor materials both play a critical role in determining the performance of PSCs. Among the various conjugated-polymer donor materials, polythiophene (PT) derivatives such as poly(3-hexylthiophene), have attracted considerable interest due to their high hole mobility and simple synthesis. However, there are limited studies on the applications of PT derivatives in non-fullerene PSCs. Fabrication of highly efficient non-fullerene PSCs utilizing PT derivatives as the donor is a challenging topic. In this study, a new PT derivative, poly[5, 5′-4, 4′-bis(2-butyloctylsulphanyl)-2, 2′-bithiophene-alt-5, 5′-4, 4′-difluoro-2, 2′-bithiophene] (PBSBT-2F), with alkylthio groups and fluorination was synthesized for use as the donor in non-fullerene PSC applications. The absorption spectra, electrochemical properties, molecular packing, and photovoltaic properties of PBSBT-2F were investigated and compared with those of poly(3-hexylthiophene) (P3HT). The polymer exhibited a wide bandgap of 1.82 eV, a deep highest occupied molecular orbital (HOMO) of -5.02 eV, and an ordered molecular packing structure. Following this observation, PSCs based on a blend of PBSBT-2F as the donor and 3, 9-bis(2-methylene-(3-(1, 1-dicyanomethylene)-indanone)-5, 5, 11, 11-tetrakis(4-hexylphenyl)-dithieno-[2, 3-d:2′, 3′-d′]-s-indaceno[1, 2-b:5, 6-b′]dithiophene (ITIC) as the acceptor were fabricated. The absorption spectra were collected and the energy levels were found to be well matched. These devices exhibited a power conversion efficiency (PCE) of 6.7% with an open-circuit voltage (V_OC) of 0.75 V, a short-circuit current density (J_SC) of 13.5 mA·cm^-2, and a fill factor (FF) of 66.6%. These properties were superior to those of P3HT (1.2%) under the optimal conditions. This result indicates that PBSBT-2F is a promising donor material for non-fullerene PSCs.     

Graphitic Carbon Nitride Microspheres Supportedα-FeO(OH)Hybrids for Visible Light Photodegradation of MO

Graphitic carbon nitride(g-C3N4)microspheres supported a-FeO(OH)hybrids[α-FeO(OH)/g-C3N4]were prepared by means of a self-assembly method in deionized water.By UV-visible diffiise reflectance spectroscopy,it has been confirmed thatα-FeO(OH)/g-C3N4 has a wider absorption range thanThe feature ofα-FeO(OH)/g-C3N4 can be attributed to the efficient separation of the electron-hole pairs with photoluminescence spectra.The degradation rate of methyl orange(MO)is up to 99%under the optimal conditions of 110 min,initial concentration of 30 mg/L,anα-FeO(OH)/g-C3N4 dosage of 15 mg as well as visible light.The mechanism for this photocatalytic reaction was proposed,with hydroxyl radicals being a major active catalytic species.     

A Smartphone-assisted Paper-based Analytical Device for Fluorescence Assay of Hg2+

Rapid, efficiency and portable detection systems in low-resource settings with limited laboratory equipment and technical expertise are urgently needed. Herein, an integrated platform composed of a paper-based analytical device and a smartphone detection system for Hg²⁺ onsite testing was developed. Nitrogen-doped carbon dots(N-CDs) were synthesized by a simple hydrothermal method using citric acid as the carbon source and ethanediamine as the nitrogen source, which gave out bright blue fluorescence under the excitation at 350 nm UV light and the absolute fluorescence quantum yield was 17.1%. The fluorescence of the prepared N-CDs can be effectively quenched by Hg²⁺. In addition, an external attachment of smartphone for illumination and external light interference was designed to trace the fluorescence signals, and a software application of Android system with simple operation program was developed to perform snapshot and image processing. The smartphone-assisted detection system was combined with the N-CDs decorated paper chip to achieve the sensitive detection of Hg²⁺ in water samples. This integrated method for reliable sensing of Hg²⁺ shows a good linear detection range of 10-800 μmol/L(R²=0.9595) with detection limit of 1.07×10^-8 mol/L.     

基于数字图像颜色提取的土壤有机质预测研究

有机质是土壤质量的重要判定标准,其快速测定可为精准农业的实施提供基本的数据支撑。传统有机质测定法,通过野外取样,实验室化学分析,不仅费时费力,还效率低,完全不能满足现今社会发展对土壤信息的大量需求。通过光谱仪测定土壤反射率建立有机质估测模型,可快速预测有机质含量,但光谱仪价格较高,对操作环境要求严格,限制了其广泛应用。仅有RGB三波段的可见光传感器,相比光谱仪而言不仅价格便宜,还易于操作,借助其诸多优势,通过定量获取土壤表面颜色信息,解决土壤有机质快速测定问题,不管是从实用性还是经济性角度,都值得去探索研究。为验证可见光下提取数字图像颜色信息能快速预测有机质的可行性和适用性,采用数码相机获取土壤表面颜色,分析土壤表面组成特点,确定最佳取样面积,并比较不同土样制样标准(<1 mm和<0.5 mm) 与有机质的相关性,同时选取相关性高的颜色变量,通过回归分析,建立有机质预测模型。研究结果表明,以950 pixel×950 pixel作为取样面积,可以较稳定获取土样表面颜色,并减少边缘效应对取样结果的影响;对比<1 mm和<0.5 mm土样与有机质的相关性发现,<1 mm土样的RGB三波段与有机质的相关性更高,适合作为土壤颜色获取时的制样标准。在RGB三波段中,Red波段表现了与有机质的最高相关性,其相关系数为-0.70;通过对RGB三波段进行数学变换与超红(ExR)计算,可增加各颜色值与有机质的相关性,其中ExR指数表现了与有机质最高的相关性,其相关系数为-0.86。单变量建模过程中,ExR倒数模型获得了最好预测效果;多变量建模时,各颜色标准差参与建模,使颜色信息描述更为全面,明显提高了模型的预测精度,获得了最好的建模效果,其R2=0.80,RMSE=0.51,检验结果R2_val=0.84,RMSE_val=0.54,能较好反应研究区有机质变异特点。通过黑土检验所建模型的预测效果,仅单变量Red波段模型表现出较好预测结果,其检验结果表明红波段是有机质较为敏感波段,在不同土类中具有通用性。虽然研究中所建模型难以扩展到对其他土类的预测,但对同类土壤预测效果表明,数码相机作为颜色定量获取的工具,具有实现快速预测土壤有机质的潜力。     

悬浮固化分散液液微萃取-高效液相色谱法测定水体中邻苯二甲酸酯

建立了悬浮固化分散液液微萃取（SFO-DLLME）结合高效液相色谱（HPLC）快速测定水样中6种邻苯二甲酸酯（PAEs）的分析方法。通过对影响萃取效率因素的优化,确定了最佳萃取条件：十二烷醇萃取剂20 μL、萃取温度60℃、离子强度20 g/L、萃取时间1 min。6种PAEs在2~2000 μg/L范围内呈良好的线性关系,相关系数（r）为0.9995~0.9999,检出限（S/N=3）为0.3~0.6 μg/L。对自来水、湖水、江水、污水、海水、市售塑料瓶装纯净水和矿泉水进行测定,能检测到部分PAEs。对加标水样进行回收率试验（10、100和1000 μg/L）,6种PAEs的回收率为84.9%~94.5%,相对标准偏差为4.1%~6.8%（n=5）。该法环保、简单,可用于实际水样中6种PAEs的检测分析。     

用于同时多层MRI的选择性射频脉冲的优化设计

近年来,为提高磁共振成像（MRI）信号信噪比（SNR）、缩短成像时间,同时多层成像技术受到了极大的关注.为了实现同时多层的选择性激发,现有的多层成像序列大多使用组合射频（RF）脉冲,该脉冲可包含多个独立的幅值相同相位不同的简单脉冲,由于其采用简单的线性叠加方法,该类脉冲射频功率随脉冲数量呈现平方增长,因而应用受限.针对这一问题,基于自旋动力学和优化控制原理,本文提出了一种针对同时多层MRI的选择性射频脉冲的数值优化方法,该方法充分运用射频脉冲的调控机制,获得优化脉冲,并配合层选梯度,可实现任意层厚、层间距、层数的同时高效选择性激发.最后,通过数字模体的同时多层模拟成像实验验证了优化脉冲的有效性.     

S-和R-五味子丙素非对映异构体的圆二色谱研究

园二色谱(CD)是测定有机化合物绝对构型的常用方法。文章用圆二色谱仪对合成的4个联苯类化合物进行了表征(2个非桥键联苯化合物和2个桥键联苯化合物),得到两对几乎完全对称的圆二色谱谱图。根据其圆二色谱Cotton效应确定了4个化合物的联苯键的绝对构型。化合物3分别在256 nm出现负的Cotton效应,且在220 nm出现正的Cotton效应,表明这个化合物是S-构型;而化合物3’出现了相反的Cotton效应,表明这个化合物是S-构型。由化学相关法可以得知化合物2是R-构型, 化合物2’是R-构型。通过这些数据得出结论, 以S-噁唑啉为手性合成子的Ullmann反应得到的是S-构型联苯类化合物, 而以S-噁唑啉为手性合成子的Ullmann反应得到的是R-构型型联苯类化合物。     

固体进样石墨炉原子吸收光谱技术在测定大鼠脑铁含量中的应用

石墨炉原子吸收光谱法是测定动物脑组织Fe含量的常用方法,然而由于传统的液体进样方法中,样品前处理阶段用硝酸消解周期长,成本高耗时长,限制了原子吸收光谱技术在测定动物组织中Fe含量的应用。文章以SD大鼠脑部海马、纹状体、皮层为实验材料,采用固体进样器进样,利用石墨炉原子吸收光谱技术对各组织中的Fe含量进行了测定,并与传统法方法——硝酸消解样品后,液体进样的石墨炉原子吸收光谱测定结果做了比较,结果表明这两种方法所测结果无显著性差异,但应用固体进样法,样品前处理阶段明显简单,显著节省了样品准备时间,降低了工作量,使测定时间明显缩短,成本明显降低,并且能够有效避免外界因素对测定结果的影响,为固体进样法的进一步应用奠定了基础。     

高声压级时多孔金属板的吸声特性研究

针对高声压级下有限厚度多孔金属板在线性阻抗背衬条件下(背衬表面声压与声质点速度为线性关系)的吸声问题,提出了一个描述不同声压级下材料层法向吸声性能的一维模型,并给出求解材料层内部声质点速度的线化与差分方法,以预测多孔金属板在高声压级下的非线性吸声特性。在阻抗管中对两块多孔金属板进行了声学测试,得到了材料层法向表面阻抗和吸声系数随入射声压级变化的实验结果。研究表明:实验与理论预测符合良好,验证了模型与数值方法的正确性。本文所提原理和方法,可用于一般硬质多孔材料。      

NEA GaN光电阴极表面模型研究

针对目前NEAGaN光电阴极研究中Cs激活或Cs/O激活后表面状态的形成过程还不清楚的问题,围绕NEAGaN光电阴极的光电发射机理,结合GaN光电阴极激活过程中出现的现象及成功激活的最终效果,给出了GaN光电阴极铯氧激活后的表面模型[GaN(Mg):Cs]:O-Cs。利用该模型可很好地解释单独用Cs激活时约-1.0eV的有效电子亲和势和Cs/O共同激活时-1.2eV的有效电子亲和势的成因,也较好地解释了表面吸附原子的组合形式,即Cs/O激活后激活层的化学结构由Cs2O2和CsO2构成。