Carbon spheres with rational designed surface and secondary particle-piled structures for fast and stable sodium storage

The electrochemical performance of hard carbon in sodium storage is still limited by its poor cycling stability and rate capability because of the sluggish kinetics process.In this study,we use a simple and effective method to accelerate the kinetics process by engineering the structure of the electrode to promote its surface and near-surface reactions.This goal is realized by the use of slightly aggregated ultra-small carbon spheres.The large specific surface area formed by the small spheres can provide abundant active sites for electrochemical reactions.The abundant mesopores and macropores derived from the secondary particle piled structure of the carbon spheres could facilitate the transport of electrolytes,shorten the diffusion distance of Na⁺and accommodate the volume expansion during cycling.Benefiting from these unique structure features,PG700-3(carbon spheres with the diameters of 40-60 nm carbonized at 700℃)exhibits high performance for sodium storage.A high reversible capacity of 163 mAh g^-1 could be delivered at a current density of 1.0 A g^-1 after 100 cycles.Interestingly,at a current density of 10.0 A g^-1,the specific capacity of PG700-3 gradually increases to 140 mAh g^-1 after 10000 cycles,corresponding to a capacity retention of 112%.Given the enhanced kinetics of SIBs reactions,PG700-3 exhibits an excellent rate capability,i.e.,230 and 138 mAh g^-1 at 0.1 and 5.0 A g^-1,respectively.This study provides a facile method to attain high performance anode materials for SIBs.The design strategy and improvement mechanism could be extended to other materials for high rate applications.     

圆二色光谱法研究酸度、槲皮素、锌离子对β-酪蛋白二级结构的影响

采用圆二色光谱(CD)技术研究了酸度、槲皮素(Qct)和锌离子对溶液中β-酪蛋白(β-CN)二级结构的影响. 结果表明, 酸度、Qct和锌离子均能够诱导β-CN二级结构发生改变. 在pH 7.6的条件下, β-CN各种结构分别为32.6% α-螺旋, 53.5% β-折叠, 13.9% (-转角和无规卷曲; Qct使β-CN的α-螺旋含量增加、β-折叠含量减少; 锌离子和Zn-Qct配合物导致β-CN的α-螺旋含量大幅度降低, β-折叠含量略有增加, 同时转角和无规的含量也大幅度增加.     

基于酶催化银沉积质量放大的血吸虫压电免疫传感器的研究

发展了一种基于酶催化金属银沉积信号放大的新型高灵敏气相压电免疫传感检测技术.先将血吸虫抗原(SjAg)共价固定在石英晶体表面,制备得到血吸虫压电免疫传感器.检测时,在晶振上滴加不同浓度的待测血吸虫抗体,再将碱性磷酸酶标记的二抗通过夹心方式结合到传感器表面.然后利用碱性磷酸酶催化磷酸化的抗坏血酸酯水解从而还原硝酸银,使金属银沉积在晶振表面上,放大传感器的质量响应信号.实验结果表明该传感检测方法可显著提高气相压电免疫传感器的检测灵敏度,传感器对血吸虫抗体的响应线性范围在1～225 ng/mL,检测下限为1 ng/mL.     

Multi-spectroscopic Study on the Interaction between CdTe Quantum Dots and Bovine Serum Albumin

The interaction between CdTe quantum dots (QDs) and bovine serum albumin (BSA) was systematically investigated by fluorescence, UV‐vis absorption and circular dichroism (CD) spectroscopy under physiological conditions. The experimental results showed that the fluorescence of BSA could be quenched by CdTe QDs with a static quenching mechanism, indicating that CdTe QDs could react with BSA. The quenching constants according to the modified Stern‐Volmer equation were obtained as 1.710×10⁶, 1.291×10⁶ and 1.010×10⁶ L·mol^?1 at 298, 304, and 310 K, respectively. ΔH, ΔS and ΔG for CdTe QDs‐BSA system were calculated to be ?33.68 kJ·mol^?1, 6.254 J·mol^?1·K^?1 and ?35.54 kJ·mol^?1 (298 K), respectively, showing that electrostatic interaction in the system played a major role. According to F?rster theory, the distance between Trp‐214 in BSA and CdTe QDs was given as 2.18 nm. The UV‐vis, synchronous fluorescence and CD spectra confirmed further that the conformations of BSA after addition of CdTe QDs have been changed.     

A co-templated approach to hierarchically mesoporous–macroporous bioactive glasses (MMBG) scaffolds for bone tissue regeneration

In this paper, one kind of well-ordered hierarchical mesoporous–macroporous bioactive glasses (MMBG) scaffolds with large pore size of 60–120 μm and mesoporous phase in inner-wall has synthesized successfully. This method used stem core of corn as macroporous template and P123 as mesoporous template. The final samples have replicated the structure of the macroporous plant templates precisely. Since the aperture and pore structure of different plants are variable, it provides a possible way for the synthesis of materials with various aperture holes and pore structure. The organizational structure of final sample is benefit to transport and storage guest molecule, making these hierarchical porous materials have more superior performance and application in the field of macromolecules separation, bone tissue regeneration, and drug delivery, etc. The in vitro tests indicated hierarchical MMBG scaffolds have well capacity for inducing the HA growth. They have the potential to satisfy the demands of bone tissue engineering regeneration.     

含二氮杂荼酮结构新型聚芳醚系列高性能聚合物的合成与性能

从分子结构设计出发 ,以价廉易得的苯酚、苯酐为原料 ,经温和的工艺合成了结构全新的 4 ( 4′ 羟基苯基 ) 2 ,3 二氮杂萘 1 酮 (DHPZ) ,对其合成反应路线、合成反应动力学、反应机理进行了深入研究 .在大量实验研究基础上 ,结合分子立体结构的计算机模拟 ,确认其具有非共平面扭曲结构特征 ,其N—H键和O—H键具有类似的反应活性 ,是一种类似双酚的新单体 .以DHPZ与多种市售双卤单体如二氟二苯酮 (DFK)、二氯二苯砜 (DCS)、二氯二苯双酮 (DCKK)、二氯二苯腈 (DCBN)等经溶液亲核取代逐步聚合反应制得一系列含二氮杂萘酮结构的新型高性能聚醚砜 (PPES)、聚醚酮 (PPEK)、聚醚砜酮 (PPESK)、聚醚酮酮 (PPEKK)、聚醚砜酮酮(PPESKK)、聚醚腈酮 (PPENK)、聚醚腈砜 (PPENS)、聚醚腈砜酮 (PPENSK)等 ,对其结构进行了谱学表征 ,对其性能进行了全面测试 ,研究了其结构与性能关系 .谱学数据证明皆为无定型高聚物 .其玻璃化温度Tg 在 2 5 0～370℃之间 ,可以通过取代基团结构或主链上砜 酮基团比例进行调控 .在大量实验研究基础上 ,创造性提出“引入全芳环非共平面扭曲分子链结构赋予高聚物既耐高温又可溶解的优异综合性能”的分子结构设计理论 .在此分子设计理论指导下 ,设计并合成了含联苯二氮杂萘酮结构的新型二     

含4-苯基二氮杂萘酮结构共聚芳酯的合成及性能

以4-[4-(4羧基苯氧基)苯基]-2-(4-羧基苯基)二氮杂萘-1-酮(DHPZ-DA)、4,4'-二羧基二苯醚(DAPE)和2,2'-二(4-羟基苯基)丙烷(PBA)为原料,采用溶液缩聚法,合成了一系列聚芳酯,其数均分子量在1.2×104～1.7×104之间.通过FTIR和1H-NMR对聚芳酯结构进行了表征.该系列...     

自探针荧光法研究十二烷基苯磺酸钠与TritonX-100相互作用

采用荧光光谱法研究了十二烷基苯磺酸钠（SDBS）与非离子表面活性剂TritonX-100混合体系在水溶液中聚集体的性质。 发现在浓度与荧光强度的关系曲线上存在2个转折点,分别对应于混合体系的临界胶团浓度和胶团形状发生转变的浓度。 通过混合胶团相互作用关系,计算了SDBS与TritonX-100的相互作用参数βM,说明SDBS以其自身所带生色基团苯磺酸与TritonX-100发生了协调效应且存在着较强的相互作用。     

含芳基均三嗪环耐高温低聚酰亚胺的合成与性能

通过调控聚合单体的摩尔配比,合成了一系列新型的不同分子链长度的邻苯二甲腈封端含二氮杂萘酮联苯结构低聚酰亚胺,通过FTIR、1H-NMR、WAXD和元素分析对其结构进行表征.以4,4′-二氨基二苯砜为催化剂,低聚物经常压下固化交联后,得到含芳基均三嗪环结构的热固性聚酰亚胺.低聚物表现了良好的溶解性能,可溶于N-甲基-2-...     

Brookite TiO2 quasi nanocubes decorated with Cu nanoclusters for enhanced photocatalytic hydrogen production activity

Brookite TiO₂ quasi nanocubes (BTN) decorated with various Cu nanoclusters (CuNCs) contents (hereafter referred to as Cu/BTN composite) were synthesized via a facile chemical reduction process by NaBH₄. The obtained products and its Cu's existential state were characterized by X-ray diffraction, UV–Vis diffuse reflectance absorption spectroscopy, electron microscopy, X-ray photoelectron spectroscopy and X-ray fluorescence spectroscopy. It was found that the introduction of CuNCs with small size of ～1–2 nm on BTN surfaces can improve the photocatalytic H₂ production activity, and the maximum photoactivity (225 μmol h^?1) for H₂ production over 1.0 mol% Cu/BTN composite is similar to that (220 μmol h^?1) of the benchmark photocatalyst (P25) under the optimum photoreaction conditions, which is 5.2 times higher than that (42.5 μmol h^?1) of the BTN alone. This significant enhancement in the photoactivity of BTN is deemed to result from the metallic CuNCs with high surface area and dispersion, which favour the co-catalyst functions to cause an effective photogenerated carrier separation in space and an improvement in the photocatalytic activity and stability for H₂ production. The present results not only demonstrate the brookite TiO₂ would be a potential effective photocatalyst for H₂ production, but also provide an inexpensive, efficient and stable means of enhancing light-to-hydrogen energy conversion by using metallic Cu nanoclusters alternative to the commonly used noble metal co-catalyst.