Preparation of pillared layered antimony hydroxide and its flame retardancy in thermoplastic polyurethane

Journal of Thermal Analysis and Calorimetry - In this article, a pillared layered antimony hydroxide (Sb-LH) material has been prepared by the hydrothermal method. X-ray diffraction,...     

Solution-Based,Anion-Doping of Li4Ti5O12 Nanoflowers for Lithium-Ion Battery Applications

Solution-based, anionic doping represents a convenient strategy with which to improve upon the conductivity of candidate anode materials such as Li₄Ti₅O₁₂ (LTO). As such, novel synthetic hydrothermally-inspired protocols have primarily been devised herein, aimed at the large-scale production of unique halogen-doped, micron-scale, three-dimensional, hierarchical LTO flower-like motifs. Although fluorine (F) doping has been explored, the use of chlorine (Cl) dopants is the primary focus here. Several experimental variables, such as dopant amount, lithium hydroxide concentration, and titanium butoxide purity, were probed and perfected. Furthermore, the Cl doping process did not damage the intrinsic LTO morphology. The analysis, based on interpreting a compilation of SEM, XRD, XPS, and TEM-EDS results, was used to determine an optimized dopant concentration of Cl. Electrochemical tests demonstrated an increased capacity via cycling of 12 % for a Cl-doped sample as compared with pristine LTO. Moreover, the Cl-doped LTO sample described in this study exhibited the highest discharge capacity yet reported at an observed rate of 2C for this material at 143mAh g⁻¹. Overall, these data suggest that the Cl dopant likely enhances not only the ion transport capabilities, but also the overall electrical conductivity of our as-prepared structures. To help explain these favorable findings, theoretical DFT calculations were used to postulate that the electronic conductivity and Li diffusion were likely improved by the presence of increased Ti³⁺ ion concentration coupled with widening of the Li migration channel.     

Characterization of Different Salt Forms of Chitooligosaccharides and Their Effects on Nitric Oxide Secretion by Macrophages

In this paper, chitooligosaccharides in different salt forms, such as chitooligosaccharide lactate, citrate, adipate, etc., were prepared by the microwave method. They were characterized by SEM, FTIR, NMR, etc., and the nitric oxide (NO) expression was determined in RAW 264.7 cells. The results showed that pure chitooligosaccharide was an irregular spherical shape with rough surface, and its different salt type products are amorphous solid with different honeycomb sizes. In addition to the characteristic absorption peaks of chitooligosaccharides, in FTIR, the characteristic absorption of carboxyl group, methylene group, and aromatic group in corresponding acid appeared. The characteristic absorption peaks of carbon in carboxyl group, hydrogen and carbon in methyl, methylene group, and aromatic group in corresponding acid also appeared in NMR. Therefore, the sugar ring structure and linking mode of chitooligosaccharides did not change after salt formation of chitooligosaccharides. Different salt chitooligosaccharides are completely different in promoting NO secretion by macrophages, and pure chitooligosaccharides are the best.     

Synthesis and surfactochromicity of 1,4‐diketopyrrolo[3,4‐c]pyrrole(DPP)‐based anionic conjugated polyelectrolytes

Two novel anionic conjugated copolyelectrolytes PSDPPPV and PSDPPPE were synthesized via Heck/Sonogashira coupling reactions and characterized by FT‐IR, ¹H NMR, UV‐vis, and PL spectroscopy. The two polymers are respectively constituted of 2,5‐diethoxy‐1,4‐phenyleneethynylene (DPV) and 2,5‐diethoxy‐1,4‐phenyleneethynylene (DPE) with 1,4‐diketo‐2,5‐bis(4‐sulfonylbutyl)‐3,6‐diphenylpyrrolo[3,4‐c]pyrrole (SDPP) which is a novel water soluble diketopyrrolopyrrole derivative. PSDPPPV and PSDPPPE show broad absorption band in visible region and they exhibit strong fluorescence quenching in aqueous solution. The fluorescence of their aqueous solutions can be enhanced in the presence of cationic surfactant or polymer nonionic surfactant. Fluorescence enhancement by introduction of polyvinylpyrrolidone (PVP) shows linear response. This result provides a controllable method to increase fluorescence intensity of dipyrrolopyrrole‐based conjugate polyelectrolytes in aqueous phase. The optical properties suggested that PSDPPPV and PSDPPPE which are negatively charged conjugated polymers can assemble with positively charged photovoltaic materials to form ionic photoactive layer. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 739–751     

Combustion behavior and thermal stability of TPU composites based on layered yttrium hydroxides and graphene oxide

Journal of Thermal Analysis and Calorimetry - Layered yttrium hydroxides (LYH)- and graphene oxide (GO)-supported layered yttrium hydroxides (GO–LYH) were synthesized by a co-precipitation...     

低共熔溶剂分散液液微萃取-悬浮固化-高效液相色谱法测定水产品中3种内分泌干扰物的含量北大核心CSCD

将癸酸和香叶醇在10 mL玻璃管中以2∶1的物质的量之比混合,然后将混合物在80℃水浴锅中加热,直至形成稳定的低共熔溶剂(DES)。该溶剂易合成、低成本、低毒性且具有高生物降解性,是一种新型的疏水性DES,可用于水产品中内分泌干扰物的微萃取。取已粉碎的水产品样品1 g和乙腈2 mL置于5 mL离心管中,以转速2 000 r·min^(-1)涡旋振荡3 min。取上清液400μL,经0.45μm滤膜过滤,滤液与100μL DES混合,并迅速注入装有5 mL 80 g·L^(-1)氯化钠溶液的10 mL离心管中,以完成DES的分散。将上述离心管以转速3 500 r·min^(-1)离心5 min,然后置于冰浴中进行固化。将固化后所得样品溶解于150μL甲醇中,以Eclipse Plus C;色谱柱为分离柱,以体积比90∶10的甲醇-水的混合液为流动相,在激发波长228 nm,发射波长305 nm处测定双酚A、4-叔辛基苯酚和壬基酚等3种内分泌干扰物的含量。结果表明,DES在冰浴中固化,可促进其从水溶液中分离,简单且快速,利于萃取剂的收集。3种内分泌干扰物的质量分数均在0.25~10μg·g^(-1)内与其对应的峰面积呈线性关系,检出限(3S/N)均为0.075μg·g^(-1)。用此法对空白加标样品进行测定,测定值的日内和日间相对标准偏差(n=5)均小于4.0%。以空白样品为基体进行加标回收试验,所得回收率为78.7%~91.6%。     

Optimizing Age Penalty in Time-Varying Networks with Markovian and Error-Prone Channel State

In this paper, we consider a scenario where the base station (BS) collects time-sensitive data from multiple sensors through time-varying and error-prone channels. We characterize the data freshness at the terminal end through a class of monotone increasing functions related to Age of information (AoI). Our goal is to design an optimal policy to minimize the average age penalty of all sensors in infinite horizon under bandwidth and power constraint. By formulating the scheduling problem into a constrained Markov decision process (CMDP), we reveal the threshold structure for the optimal policy and approximate the optimal decision by solving a truncated linear programming (LP). Finally, a bandwidth-truncated policy is proposed to satisfy both power and bandwidth constraint. Through theoretical analysis and numerical simulations, we prove the proposed policy is asymptotic optimal in the large sensor regime.     

Highly sensitive trivalent copper chelate-H2O2 system for CE-chemiluminescent detection of luminol-type compounds

Luminol-type compounds can be used as chemiluminescent (CL) derivatization reagents for amines, carboxylic acids and protein. Copper chelate diperiodatocuprate(III) (K5[Cu(HIO6)2], DPC) was synthesized by complexation of copper at trivalent oxidation state and periodate in a strong basic medium. It was found that DPC can greatly enhance the reaction between luminol-type compounds and H2O2 to produce very strong CL emission. Based on this fact, a rapid CE method combined with high-sensitive end-column CL detection was established to simultaneously analyze luminol and N-(4-aminobutyl)-N-ethylisoluminol (ABEI) with wide concentration range of 3.0-300 nmol/L in 5 min. The RSDs of the signal intensity and the migration time were less than 3.9 and 7.0% for a standard sample containing 100 nmol/L luminol and ABEI (n=5), respectively. The investigation implies that DPC is a promising sensitizer for CE-CL detection of a great variety of biomolecules and drugs in biological samples after derivatization using luminol derivatives.     

One-pot syntheses of novel pyrazole-containing bisphosphonate esters at room temperature

An efficient general synthetic approach has been developed to synthesize pyrazole-containing bisphosphonate (N-BPs) esters from chromenone derivatives via a sequential two-step reaction in one pot at ambient temperature in good to excellent yields. This protocol provides a new convenient method to prepare lipophilic bisphosphonate precursors with potential activities.