scholarly journals One-Step Synthesis of Eu3+-Modified Cellulose Acetate Film and Light Conversion Mechanism

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 113
Author(s):  
Zhihui Zhang ◽  
Zhengdong Zhao ◽  
Yujia Lu ◽  
Di Wang ◽  
Chengyu Wang ◽  
...  
Keyword(s):  
Cellulose Acetate ◽  
High Efficiency ◽  
Red Light ◽  
High Tensile Strength ◽  
Experimental Conditions ◽  
Cellulose Acetate Film ◽  
One Step ◽  
Agricultural Films ◽  
Modified Cellulose ◽  
Coordination Reaction

A CA-Eu(III) complex was synthesized by the coordination reaction of cellulose acetate (CA) and Eu3+ to obtain a CA-Eu light conversion film. This product was then doped with Tb(III) to sensitize the luminescence of Eu3+, which could functionalize the CA film. FTIR and XPS showed that the oxygen atoms in C=O, C–O (O=C–O), and O–H were involved in the complexation with Eu3+ and formed a Eu–O bond. SEM revealed that Eu3+ filled in the pores of the CA film. By changing the experimental conditions, the best fluorescence performance was obtained at the CA: Eu3+ ratio of 3:1 with a reaction time of 65 min. The energy transfer between Tb3+–Eu3+ could be realized by doping Tb3+ to enhance the luminescence of Eu3+. The best fluorescence performance of the CA-Eu-Tb light conversion film was at a Eu3+:Tb3+ ratio of 3:1. Compared with the CA film, the light conversion film has high transparency, high tensile strength, and good flexibility. It can convert the ultraviolet light harmful to plants into red light that is beneficial to photosynthesis. This offers high efficiency and environmental protection in the field of agricultural films.

One-step Separation and Purification of Four Phenolic Acids from Stenoloma chusanum (L.) Ching by Medium-pressure Liquid Chromatography and High-speed Counter-current Chromatography

2019 ◽  
Vol 9 (2) ◽  
pp. 138-143
Author(s):  
Tianyun Li ◽  
Xiling Dai ◽  
Yichen Li ◽  
Guozheng Huang ◽  
Jianguo Cao
Keyword(s):  
Natural Products ◽  
Liquid Chromatography ◽  
Phenolic Acids ◽  
High Speed ◽  
High Efficiency ◽  
Total Phenolic ◽  
Medium Pressure ◽  
Medium Pressure Liquid Chromatography ◽  
One Step ◽  
Counter Current

Background:Stenoloma chusanum (L.) Ching is a Chinese traditional medicinal fern with high total flavonoid and total phenolic content. Traditionally, phenolic compounds were separated by using column chromatography, which is relatively inefficient. </P><P> Objective: This study aims to use an efficient method to separate natural products from S. chusanum by Medium-Pressure Liquid Chromatography (MPLC) and High-Speed Counter-Current Chromatography (HSCCC).Methods:In the present research, firstly, a sample (2.5 g) from the dichloromethane extract of S. chusanum was separated by MPLC. Next, fraction P5 was purified by HSCCC with a two-phase solvent system composed of hexane-ethyl acetate-methanol-water (HEMWat) at a volume ratio of 2:4:1:4 (v/v/v/v). </P><P> Result: Four phenolic acids were obtained and their structures were identified by means of NMR and ESI-mass analysis. They were identified as: 1) protocatechuic acid (34 mg, purity 90.1%), 2) syringic acid (66 mg, purity 99.0%), 3) p-hydroxybenzoic acid (5 mg, purity 91.2%) and 4) vanillic acid (6 mg, purity 99.3%).Conclusion:The combination of MPLC and HSCCC is a high-efficiency separation method for natural products. This is the first report with regard to the separation of four phenolic acids in one step by MPLC and HSCCC from S. chusanum (L.) Ching.

Well-designed honeycomb Co3O4@CdS photocatalyst derived from cobalt foam for high-efficiency visible-light H2 evolution

2021 ◽  
Author(s):  
Chao Zhang ◽  
Baoquan Liu ◽  
Weiping Li ◽  
Xiangxue Liu ◽  
Ke Wang ◽  
...  
Keyword(s):  
Visible Light ◽  
Water Splitting ◽  
High Efficiency ◽  
H2 Evolution ◽  
One Step

Well-designed honeycomb Co3O4@CdS (H-Co3O4@CdS) was fabricated via a one-step strategy for efficient water splitting. During the decoration of CdS, honeycomb Co3O4 (H-Co3O4) with macropore was formed simultaneously. H-Co3O4 could enhance...

scholarly journals Temperature Dependence of Limiting Fluorescence Anisotropy of POPOP in Cellulose Acetate Film

1985 ◽  
Vol 40 (6) ◽  
pp. 559-561
Author(s):  
A. Kawski ◽  
A. Kubicki ◽  
I. Weyna ◽  
I. Janić
Keyword(s):  
Temperature Dependence ◽  
Cellulose Acetate ◽  
Fluorescence Anisotropy ◽  
Thermal Relaxation ◽  
Effect Of Temperature ◽  
Torsional Vibrations ◽  
Slow Increase ◽  
Cellulose Acetate Film ◽  
Luminescent Centre

The effect of temperature (103 K < T < 303 K) upon the limiting fluorescence anisotropy r0 of POPOP was investigated in a cellulose acetate film. A slow increase in r0 was observed when reducing the temperature. Based on the Jabłoński theory, the frequency of the torsional vibrations of POPOP was determined to be w = 1.3 x 1012s−1. The depolarization due to these torsional vibrations was found to occur immediately following excitation during the thermal relaxation of the luminescent centre, thus somewhat lowering the value of the fundamental fluorescence anisotropy rf to the limiting r0 value.

A Powerful One‐Step Puffing Carbonization Method for Construction of Versatile Carbon Composites with High‐Efficiency Energy Storage

2021 ◽  
pp. 2102796
Author(s):  
Shenghui Shen ◽  
Lei Huang ◽  
Xili Tong ◽  
Rongfan Zhou ◽  
Yu Zhong ◽  
...  
Keyword(s):  
Energy Storage ◽  
High Efficiency ◽  
Carbon Composites ◽  
One Step

High-angle Kikuchi patterns

1954 ◽  
Vol 221 (1145) ◽  
pp. 224-242 ◽  
Keyword(s):  
Lithium Fluoride ◽  
High Efficiency ◽  
Cylindrical Specimen ◽  
Angle Of Incidence ◽  
High Angle ◽  
Lead Sulphide ◽  
Marked Contrast ◽  
Experimental Conditions ◽  
Low Intensity ◽  
Glancing Angle

A cylindrical specimen chamber and camera have been used to study the high-angle Kikuchi patterns obtained by reflexion of electrons, of energy 6 to 50 keV, from the cleavage surfaces of crystals with the sodium chloride structure. Angles of scattering ranging from 0 to 164° were covered. The relative intensity of the pattern at different scattering angles was measured using a photographic technique. The intensity distribution was found to become less steep as the energy of the incident electrons decreased. In photographs taken with a large value of the glancing angle of incidence, defect bands were found, starting near the shadow edge of the pattern; these changed to excess bands at higher angles of scattering. The most striking feature of the results is the remarkable intensity and clarity at the highest scattering angles of the pattern produced by crystals such as lead sulphide and potassium iodide, the constituents of which have a relatively high elastic scattering cross-section. In marked contrast, a relatively low intensity and low clarity was found at these angles for lithium fluoride under the same experimental conditions. An investigation of the width of Kikuchi bands, visible over the whole available angular range, showed that the electrons forming these bands had the same energy as that of the incident electrons within the experimental error of 10%. A possible mechanism is discussed by means of which electrons can be diffused through large angles with high efficiency, relative to small angles, and with relatively little loss of energy.

Sign in / Sign up

Export Citation Format

Share Document