JOURNAL OF LUMINESCENCE
·
2016
·
IF 2.693
Min Zhou,Ailian Wang,Cong Li,Xiaowei Luo,Yongjun Ma
A novel flow-injection chemiluminescence method (FI-CL) was established for the determination of methionine in this paper, based on its strong enhancement on CL intensity of the luminol-KIO 4 system catalyzed by thioglycolic acid-capped CdTe quantum dots in alkaline media. Under the optimized conditions, the relative CL intensity was in proportion to methionine concentration in the range from 1.0×10 − 8 to 1.0×10 −5 g mL −1 with a detection limit of 6.6×10 −9 g mL −1 (3σ). The relative standard deviation (RSD) of the CL intensity for 1.0×10 −6 g mL −1 standard methionine solution was 0.97% (n=11). The proposed method was successfully applied to determine methionine in commercial pharmaceutical formulations with recoveries between 98.0% and 101.9%. The possible CL mechanism was discussed as well.
研究领域:
分析化学
·
药学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2022
·Vol. 147
·期 23
·13253-13259
·
IF 4.755
Chen Yiyang,Wu Weihong,Zhang Man,Cui Yumeng,Zhang Kailun,Qu Hongqiang
The thermal degradation and flame retardancy effect between ionic liquid-modified graphene and hexaphenoxy cyclotriphosphazene on epoxy resin (EP) was investigated using thermogravimetric analysis, differential thermogravimetric analysis, thermogravimetric analysis-infrared spectrometry (TGA-FTIR) and the char residue analysis. The carbonization and synergistic flame-retardant mechanism were obtained. The results showed that, compared with pure EP, the char residue amount of flame-retardant EP was increased, which was dense and continuous with fewer and smaller pores. This was due to the compatibilization of the ionic liquid to the matrix, resulting in the good dispersion of the flame retardant in EP matrix to promote the carbonization efficiency. The TGA-FTIR analysis showed that the PO·and HF free radicals produced by decomposition of flame retardants quenched the flame in the gas phase, and the produced water vapor and NH 3 diluted the concentrations of combustible gas and oxygen to inhibit the progress of combustion. Graphical abstract
研究领域:
材料科学
·
燃烧学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
·
2025
·
IF 7.8
Guanxiang Wang,Chaoqun Li,Wenqing Xu,Xianchun Li,Yixi Wang,Tingyu Zhu
High proportion flue gas recirculation reduces oxygen content, affecting sintering production. To address combustion inhibition under low oxygen conditions, this study examines the impact of quasi-particle structure on combustion characteristics in hypoxic environments. The combustion characteristics of one-dimensional quasi-particles were quantitatively analyzed using non-isothermal and isothermal thermogravimetric experiments. The reactivity index and reaction rate constant of CaO-coated coke increased by 26.6% and 15%, respectively, compared to pure coke under 15% O₂ conditions. Subsequent studies have shown that CaO-coating increases the number of active sites and extends the diffusion path of combustion products, significantly enhancing the catalytic combustion effect. These findings were used to propose a CaO premixed low-oxygen sintering scheme. The effect of low-oxygen sintering of two-dimensional discrete fuels on production indexes was investigated by sintering pot experiments. Experimental results indicate that CaO premixing increases vertical sintering speed by 6.33%, enhancing productivity by 5.45%. Furthermore, the melting time of the surface layer is prolonged by 50%, leading to a 12.6% yield increase and a 1.9% improvement in drum strength. This study confirms that CaO premixing meets production requirements at 15% O 2 , thus providing data basis for improvements in the sinter flue gas recirculation rate.
研究领域:
冶金工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL POLLUTION
·
2020
·
IF 6.793
Yi Liu,Ruojia Li,Jianping Yu,Fengli Ni,Yingfei Sheng,Austin Scircle,James V. Cizdziel,Ying Zhou
Microplastics are ubiquitous in the marine environment but characterizing them in marine organisms is challenging. Herein we describe a method to detect, identify, and quantify microplastics in marine mussels ( Mytilus edulis ) using thermal gravimetric analysis – Fourier Transform infrared spectroscopy – gas chromatography mass spectrometry (TGA-FTIR-GC/MS) after extracting and isolating the microplastics using chemical digestion, density separation, and filtration. Combining the three instrumental techniques adds discriminatory power as temperature profiles, chromatograms, and vibrational and mass spectra differ among common plastics. First, we tested several digestion schemes after spiking the mussels with plastics commonly found in the marine environment, including polyethylene (PE), polystyrene (PS), polypropylene (PP) and polyvinyl chloride (PVC). KOH (10%, w/v) was the most suitable reagent, providing good recoveries (>97%) without degrading the microplastics. We show that the technique TGA-FTIR-GC/MS can be optimized to readily determine both the type (polymer) and amount (mass) of microplastics in the sample. Applied to 100 mussels from each of six locations along the coast of China, we found an average of 0.58 mg of plastic per kg of tissue (range 0.16–1.71 mg/kg), with PE being the most abundant type of plastic measured. Among the coastal cities, mussels from Dalian had the highest microplastic content. Overall, we demonstrate that the method is a powerful technique to quantify masses of microplastics in marine mussels, a species commonly used as a bioindicator of pollution, and may be applied to other biota as well.
研究领域:
环境科学
·
海洋生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
LUMINESCENCE
·
2019
·Vol. 34
·期 7
·673-679
·
IF 1.691
Min Zhou,Qiqi Chen,Ailian Wang,Juanhua Li,Yongjun Ma
The chemiluminescence (CL) behaviour of the luminol–potassium periodate system enhanced by CdTe quantum dots capped with thioglycolic acid (TGA–CdTe QDs) was studied using kinetic experiments, CL spectra, UV–vis absorption spectra and fluorescence spectra. The production of oxygen-containing reactant intermediates (O 2 •− and OH • ) in the present CL system was verified by CL. The possible CL mechanism was discussed in detail. Furthermore, theophylline (THP) was determined based on its enhancement of the CL intensity of the CdTe QDs–luminol–potassium periodate system coupled with a flow-injection technique. Under these optimized conditions, the linear range was found to be from 1.0 × 10 −8 to 1.0 × 10 −5 g/mL with a detection limit of 2.8 × 10 −9 g/mL (3σ). The recoveries for the determination of THP in tablets were from 98.2 to 99.6%.
研究领域:
分析化学
·
药学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
·
2019
·
IF 2.29
Jun-Feng Wang,Pan Liang
A pure barium borate of BaB 8 O 11 (OH) 4 ·3H 2 O has been synthesized and characterized by XRD, FT-IR, TGA, and chemical analysis. The molar enthalpies of solution of BaB 8 O 11 (OH) 4 ·3H 2 O in 1 mol dm −3 HCl(aq), and Ba(OH) 2 ·8H 2 O in the mixture solvent of {2.00 cm 3 of 1 mol·dm −3 HCl + H 3 BO 3 (aq)} were measured by microcalorimeter at T = 298.15 K, respectively. With the use of previously determined enthalpy of solution of H 3 BO 3 (s) in 1 mol·dm −3 HCl(aq), and the standard molar enthalpies of formation for Ba(OH) 2 ·8H 2 O(s), H 3 BO 3 (s), and H 2 O(l), the standard molar enthalpy of formation of −(7500.6 ± 6.5) kJ·mol −1 at T = 298.15 K was obtained based on an appropriate thermochemical cycle. Moreover, the molar enthalpy of formation of −6091.7 kJ mol −1 for [B 8 O 11 (OH) 4 ] 2− was estimated by a group contribution method, which was used to predict the Δ f H m o of a series of alkaline-earth metal borates for MB 8 O 11 (OH) 4 (M = Ca, Sr, Ba).
研究领域:
物理化学
·
无机化学
·
热化学
✓ 已验证
DOI
高影响因子
PROGRESS IN ORGANIC COATINGS
·
2022
·
IF 6.206
Shuhui Liu,Hui Xie,Qingmin Cao,Yujie Ning,Yihan Song,Chengdong Zhang,Bin Liu
This research aims to improve the protective performance of coatings in harsh corrosive conditions by using functionalized self-healing microcapsules. CeO 2 /PUF MCs and PUF MCs were prepared via one-step emulsion polymerization . The microcapsules were implanted into epoxy coatings to investigate their self-healing performance. Multiple testing techniques, including SEM, FTIR, XRD , TGA , EIS , and NSS were used to characterize the morphology, crystal structure, chemical composition, thermal properties, and self-healing performance of the microcapsules and coatings. The experimental results indicated that the CeO 2 /PUF MCs had a spherical core-shell structure with a rough surface and an average diameter of 1583 nm. Meanwhile, the minimum corrosion products and the highest low-frequency impedance were found in CeO 2 /PUF MCs coating with artificial scratch, which demonstrated that the self-healing and anti-corrosion performance were significantly improved by the newly developed bi-functional microcapsules.
研究领域:
材料科学
·
涂层技术
·
腐蚀科学
✓ 已验证
DOI
高影响因子
JOURNAL OF LUMINESCENCE
·
2019
·
IF 2.961
Yue Zhao,Tong Song,Katarzyna Matras-Postolek,Ping Yang
Highly luminescent CdTe quantum dots (QDs) is a typical luminescent material with great application potential. The photoluminescence (PL) and stability of the QDs depended strongly on Cd precursors, ligand (e.g. thioglycolic acid TGA) and preparation conditions. In this paper, CdTe QDs were prepared using Cd precursors with various molar ratios of TGA/Cd at different conditions. The composition of Cd-precursors depend strongly on the molar ratios of TGA/Cd and storage time due to the formation of Cd-TGA clusters which affects strongly the surface states of the QDs. The effect of the preparation conditions of Cd-precursors (e.g. molar ratios of TGA/Cd) on the PL peak wavelength, the full width at half maximum of PL spectra, PL quantum yields (PLQYs), fluorescence lifetime , and stability were tested in detailed. Interestingly, the PLQYs of the QDs prepared using a large molar ratio of TGA/Cd remarkably increased after Cd precursor stored in dark conditions for long time. This confirms that Cd-TGA clusters in the precursors drastically affected the synthesis of the QDs. The mechanism was discussed in detailed. These aqueous CdTe QDs with high PLQYs were obtained using a molar ratio of TGA/Cd of 1.25. In addition, the PL peak position of the QDs was red-shifted with increasing temperature, but is back to the initial value after cooling down to room temperature . Cycle test indicates red-emitting QDs reveal high stability.
研究领域:
材料科学
·
光学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2023
·
IF 3
Yuhan Chen,Nian Yin,Yunfei Wang,Shanjun Gao,Chunhui Shen
A novel bio-based carbon forming agent (Mg@PA-CS) containing P and N elements was were synthesized using the complexation characteristics of chitosan (CS) and phytate (PA). The flame retardant behavior of poly(lactic acid) (PLA)/Mg@PA-CS/APP composites (addition of 20 wt% of different ratios of Mg@PA-CS and APP to polylactic acid composites) were investigated by the limiting oxygen index (LOI), vertical burning test (UL-94), cone calorimetry test (CCT), and thermogravimetric analysis (TGA). Due to the biphasic flame retardant and synergistic effect, since the 20 wt% flame retardant system (Mg@PA-CS:APP = 1:2), PLA composites passed the UL-94 test V-0 rating, reached 34% LOI value. The peak heat release rate (PHRR) and total heat release rate (THR) were reduced to 1/2 of the pure PLA, char residue could be as high as 11.49% at 800°C. Moreover, the flame-retardant mechanism of PLA composites during thermal decomposition was analyzed using a scanning electron microscope (SEM) and the coupling techniques of TGA linked with FT-IR (TG-FTIR).
研究领域:
材料科学
·
高分子科学
·
消防安全工程
✓ 已验证
产品关联
DOI
高影响因子
FUEL PROCESSING TECHNOLOGY
·
2019
·
IF 4.507
Xiaona Lin,Lingshuai Kong,Hongzhen Cai,Qingfa Zhang,Dongmei Bi,Weiming Yi
The effects of the type and content of alkali/alkaline earth metals (AAEMs) on the co-pyrolysis of cellulose/high density polyethylene (HDPE) were studied using TGA and Py-GC/MS. AAEMs showed different effects on the decomposition characteristics of cellulose/HDPE mixtures. During cellulose/HDPE co-pyrolysis, AAEMs present in char could act as a base catalyst, with different catalytic effect on products distribution depending on the types of AAEMs. Na showed stronger catalytic cracking effect to promote alkenes formation compared to the use of K, Ca, and Mg. The comparison of experimental and calculated products distributions of raw cellulose/HDPE confirmed the existence of synergistic effect , which facilitated the cleavage of glycosidic linkages to form anhydrosugars and promoted the scission of HDPE chains to produce hydrocarbons. The effect of potassium on this synergy was also investigated. With increased potassium content, the yields of anhydrosugars and hydrocarbons decreased while the yields of furans and ketones increased, suggesting that potassium inhibited the cleavage of glycosidic bonds and promoted ring-opening reactions. This indicated that addition of potassium inhibited the synergy between cellulose and HDPE.
研究领域:
能源与燃料
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Molecular Systems Design & Engineering
·
2023
·Vol. 8
·期 12
·1492-1497
·
IF 3.6
Zichun Ding,Lishuai Zong,Chenghao Wang,Siying Wang,RunZe Liu,Xigao Jian,Jinyan Wang
The current design of phthalonitrile resins has been faced with mutual constraints between heat resistance and functionality. Instead of retaining complex heat-resistant structures in the monomer to ensure thermal performance, this study proposes a new strategy to endow carborane cages with dual identities as curing sites and heat-resistant components by utilizing the σ–π double coordination properties of cyano groups. Through the NMR tracking of the soluble B-stage resin and the XPS test of the stage cured product, it is confirmed that the cyano group was bonded to the B–H bond on the carborane cage at the initial stage of curing. In the later stage of curing, carborane is evenly dispersed in the curing network during the formation of triazine and phthalocyanine rings and becomes an inorganic filler to enhance the temperature resistance of the resin system. By performing TGA on the cured product, the 5% decomposition temperature (Td5%) of the component containing the carborane curing agent was increased by 75 °C up to 582 °C under nitrogen atmosphere. The design of this new carborane curing agent with dual functions before and after curing provides a new idea for improving the comprehensive performance of the phthalonitrile resin system.
研究领域:
材料科学
·
高分子化学
·
热工程
✓ 已验证
产品关联
DOI
高影响因子
POLYMER BULLETIN
·
2019
·Vol. 77
·期 6
·2855-2871
·
IF 1.858
Zhang Yongjie,Fan Mingshuai,Li Xiaopei
Abstract Long-chain alkyl silicone is a type of modified silicones that finds potential applications in various areas. Long-chain alkyl fluorosilicone (LCAFS) can be considered as a modified long-chain alkyl silicone as it synergistically combines the properties of long-chain alkyl silicone and novel fluorosilicone. As far as we know, reports on the synthesis of LCAFS are rare. In this report, a facile method to synthesize LCAFS was explored. It was found that silicone bearing novel C30-45 alkyls and trifluoropropyl pendent groups, namely (C30-45 alkyl) methylsiloxane/trifluoropropylmethylsiloxane copolymer (TF-AMS), could be synthesized via a simple siloxane equilibration process between silanol-terminated polytrifluoropropylmethylsiloxane and (C30-45 alkyl)methyl silicone, a commercially available silicone that is generally considered as unreactive. The chemical structure of TF-AMS was characterized unambiguously by FTIR, NMR, GPC and DSC. The thermal stabilities of TF-AMS were investigated by TGA. Based on our experimental results, a plausible mechanism for the synthesis of TF-AMS was proposed. Graphic abstract A novel long-chain alkyl fluorosilicone was synthesized via a simple yet efficient siloxane equilibration process.
研究领域:
材料科学
·
化学工程
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）