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1.
Phys Chem Chem Phys ; 26(1): 551-557, 2023 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-38086645

RESUMO

We designed a narrow-band metamaterial absorber (NMA) and an ultra-broadband metamaterial perfect absorber (UMPA) based on the impedance matching theory. The narrow-band metamaterial absorber mainly consists of Si3N4 cylinders with Si3N4 and Ti substrates. Numerical analysis shows that the absorption peak of the NMA is about 99.9% and the absorption bandwidth with more than 90% absorption is about 4.8 µm (9.5-14.3 µm). To further extend the absorption bandwidth, an ultra-broadband absorber was designed by integrating a Ti hyperbolic rectangle into the Si3N4 cylinder of the NMA. Numerical analysis shows that the absorption bandwidth of the UMPA is up to 10 µm (7-17 µm) with an average absorption rate of 96.6%. The designed UMPA has polarization insensitive properties with wide-angle absorption characteristics, and the average absorption can reach 85% and 76% in transverse magnetic (TM) and transverse electric (TE) modes, respectively, at 60° oblique incidence. The high absorption and wide band are mainly dominated by localized surface plasmon resonance, Fabry-Perot resonance and inter-resonance interactions. The designed absorber achieves excellent absorption in the long infrared wavelength band, which has potential applications in energy absorption, infrared sensing and other fields.

2.
Sci Rep ; 13(1): 17465, 2023 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-37838763

RESUMO

To further explore the pharmacological effect of pachymaran, this article studied the inhibition of pachymaran on oxidative stress and genetic damage induced by formaldehyde. 40 adult Kunming male mice were randomly divided into four groups with different interventions. One week later, the contents of serum SOD, GR, MDA, DNA-protein crosslink (DPC), 8-hydroxydeoxyguanosine (8-OHDG) and DNA adduct were determined by ELISA. The results showed that there were statistically significant differences in the contents of SOD, GR and MDA among the four groups (P < 0.01). The activity of SOD and GR increased along with the increase of pachymaran dosage (SOD: rs = 0.912, P < 0.01; GR: rs = 0.857, P < 0.01), while the content of MDA showing a significant negative correlation (rs = - 0.893, P < 0.01). There were statistically significant differences in the levels of DPC, 8-OHDG and DNA adduct among the four groups (DPC and DNA adduct: P < 0.01, 8-OHDG: P < 0.05), the concentration decreased along with the increase of pachymaran dosage (DPC: rs = - 0.855, P < 0.01; 8-OHDG:rs = - 0.412, P < 0.05, DNA adduct: γs = - 0.869, P < 0.01). It can be inferred that pachymaran can inhibit oxidative stress and DNA damage induced by formaldehyde with the dose-effect relationship.


Assuntos
Adutos de DNA , Dano ao DNA , Camundongos , Animais , Masculino , Adutos de DNA/farmacologia , 8-Hidroxi-2'-Desoxiguanosina , Estresse Oxidativo , Formaldeído/toxicidade , Proteínas/farmacologia , Superóxido Dismutase/metabolismo , Desoxiguanosina
3.
J Chromatogr A ; 1705: 464205, 2023 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-37442070

RESUMO

A new kind of covalent organic framework (COF) was first utilized as an stationary phase for open-tubular electrochromatography (OT-CEC) by in situ synthesis immobilized method at room temperature. On the basis of our previous work, 4,4',4″-(1,3,5-Triazine-2,4,6-triyl)trianiline (TZ) and 2,5-bis(2-propyn-1-yloxy)-1,4-benzenedicarboxaldehyde (BPTA) were employed as building blocks for the synthesis of COF TZ-BPTA. The coated capillary and COF TZ-BPTA were characterized by scanning electron microscopy (SEM). Then, Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) were also applied to characterize COF TZ-BPTA and the modified column. In SEM, it can be seen that COF TZ-BPTA was the spherical shape and the modified capillary was covered with globular particles equably. The COF TZ-BPTA coated column exhibited good separation resolution and efficiency towards two antiepileptic drugs and other kinds of small organic molecules involving alkylbenzene, sulfonamides, polycyclic aromatic hydrocarbon (PAH), parabens, amino acids and herbicides. The maximum column efficiency was over 2.8 × 105 plates·m-1. In addition, the precisions (RSDs) of the retention times for the alkylbenzenes of intra-day runs (n = 3), inter-day runs (n = 3) and column-to-column runs (n = 3) were all less than 1.70% and separation performance was without obvious change within 100 times run. In addition, the real sample was tested on COF TZ-BPTA coated column. Hence, COF TZ-BPTA showed great potential in the separation domain.


Assuntos
Eletrocromatografia Capilar , Estruturas Metalorgânicas , Estruturas Metalorgânicas/química , Eletrocromatografia Capilar/métodos , Espectroscopia de Infravermelho com Transformada de Fourier , Aminoácidos , Microscopia Eletrônica de Varredura
4.
J Pharm Anal ; 12(4): 610-616, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36105161

RESUMO

Covalent organic frameworks (COFs) are a novel type of crystalline porous organic polymer materials recently developed. It has several advantages in chromatographic separation field, such as high thermal stability, porosity, structural regularity, and large specific surface area. Here, a novel spherical COF 1,3,5-tris(4-aminophenyl)benzene (TAPB) and 2,5-bis(2-propyn-1-yloxy)-1,4-benzenedicarboxaldehyde (BPTA) was developed as an electrochromatographic stationary phase for capillary electrochromatography separation. The COF TAPB-BPTA modified capillary column was fabricated via a facile in situ growth method at room temperature. The characterization results of scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, and X-ray diffraction (XRD) confirmed that COF TAPB-BPTA were successfully modified onto the capillary inner surface. The electrochromatography separation performance of the COF TAPB-BPTA modified capillary was investigated. The prepared column demonstrated outstanding separation performance toward alkylbenzenes, phenols, and chlorobenzenes compounds. Furthermore, the baseline separations of non-steroidal anti-inflammatory drugs (NSAIDs) and parabens with good efficiency and high resolution were achieved. Also, the prepared column possessed satisfactory precision of the intra-day runs (n = 5), inter-day runs (n = 3), and parallel columns (n = 3), and the relative standard deviations (RSDs) of the retention times of tested alkylbenzenes were all less than 2.58%. Thus, this new COF-based stationary phase shows tremendous application potential in chromatographic separation field.

5.
Phys Chem Chem Phys ; 24(34): 20390-20399, 2022 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-35983852

RESUMO

We present a reverse design method useful for designing and analyzing metamaterial absorbers; we demonstrate its power by designing both a narrowband absorber and a wideband absorber. The method determines the structure of the absorber using an equivalent-circuit model. The narrowband metamaterial absorber structures were based on the equivalent-circuit model, and the narrowband metamaterial absorber designed using the method has an absorption fraction greater than 90% in a bandwidth of 500 nm centered at about 1450 nm. In order to extend the absorption bandwidth for the absorber, the narrowband absorber structure is adjusted based on the equivalent-circuit model, and the broadband metamaterial absorber structure is investigated. The numerical results show that the absorption bandwidth is substantially increased; the absorbance is greater than 90% for a band nearly reaching the limits of our experiment, from about 400 nm (near-ultraviolet) to about 2800 nm (deep infrared). The absorption spectrum of the wideband absorber is more sensitive to the angle of incident polarization due to the asymmetric structure, but the whole band shows polarization independence. For a large angle of 60° (TM polarization) oblique incidence, the average absorption of the broadband metamaterial absorber reaches 81%. The physical mechanism of the wideband high absorption is analyzed, which is mainly caused by Fabry-Perot resonance, surface plasmon resonance, local surface plasmon resonance, and the hybrid coupling among them. Our proposed design with high-broadband absorption has significant potential for thermoelectric and thermal emitters, solar thermal energy harvesting, and invisible device applications.

6.
Mikrochim Acta ; 189(9): 361, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-36044086

RESUMO

Covalent organic frameworks (COFs) with good chemical stability, flexible chemical functionalization, tunable pore sizes, and high specific surface areas have been increasingly employed in the field of fluorescence sensing. In this work, a crystalline vinyl-functionalized COF TzDa-V was facilely prepared through a room-temperature synthetic method via condensation reaction between 4,4',4″-(1,3,5-triazine-2,4,6-triyl)trianiline (Tz) and 2,5-diallyloxyterephthalaldehyde (Da-V). The intermolecular charge transfer (ICT) effect endowed the TzDa-V with fluorescence characteristic, and it was sensitive to trace water and can be quenched due to the disruption of ICT process by water. On this base, the prepared COF TzDa-V with excellent chemical/thermal stability was applied to sensing of trace water in common organic solvents such as DMF, acetone, THF, and ethyl acetate with rapid response (less than 10 s), satisfactory sensing range (0.5-18% water in DMF, 0.5-15% water in acetone, 0.5-16% water in THF, 0.5-5% in ethyl acetate, v/v), and high sensitivity. The limits of detection for water in DMF, acetone, THF, and ethyl acetate were 0.0497%, 0.0590%, 0.0502%, and 0.0766% (v/v), respectively. The proposed probe was successfully used for the detection of trace water in food products such as salt and sugar. The COF TzDa-V would be a good candidate for application in water sensing.


Assuntos
Acetona , Água , Fluorescência , Alimentos Crus , Solventes , Água/química
7.
J Chromatogr A ; 1678: 463343, 2022 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-35872537

RESUMO

The transformation of zero-dimensional carbon dots (CDs) to cross-linked nanomaterials is rare. In this work, a novel carbon dots-based covalent organic nanomaterial (CON CDs-TAPB) consisted of 1,3,5-tris(4-aminophenyl)-benzene (TAPB) and carbon dots (CDs) through facile Schiff-base reaction was synthesized and then employed as a stationary phase for open-tubular capillary electrochromatography (OT-CEC). The CON CDs-TAPB and the CDs-TAPB coated column were characterized through Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), UV-spectra experiments and X-ray photoelectron spectroscopy (XPS). Thanks to CON CDs-TAPB unique structure and abundant accessibility and interaction sites, the prepared column exhibited a satisfactory separation ability towards analytes including parabens, phenolic compounds. Among all analytes, the highest column efficiency was over 1.6 × 105 plates·m-1. In addition, affording methylbenzene loading capacity of 156.9 pmole, surpassing most of those materials-based OT-CEC reported thus far. Thus, the prepared carbon dots-based covalent organic nanomaterial (CON CDs-TAPB) gave a potential as a stationary phase in the separation science.


Assuntos
Eletrocromatografia Capilar , Nanoestruturas , Eletrocromatografia Capilar/métodos , Carbono , Fenóis , Espectroscopia de Infravermelho com Transformada de Fourier
8.
J Chromatogr A ; 1677: 463323, 2022 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-35853421

RESUMO

Crown ethers are macrocyclic polyether compounds containing multiple -oxo-methylene-structural units, which are often used for recognition of metal ions and ammonium ions. Inspired by the molecular design of rotaxanes, a novel covalent organic nanospheres material (CON ADBC-Tp) constructed by 4,4'-diaminodibenzo-18-crown-6 (ADBC) and 2,4,6-triformylphloroglucinol (Tp) was rationally designed as stationary phase for the separation of compounds containing imidazole structure. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR) were carried out to confirm the morphology and composition of ADBC-Tp and ADBC-Tp modified capillary column. Thanks to the introduction of crown ether building ligands, the prepared capillary column exhibited excellent separation selectivity towards protonated imidazole structure, with benzimidazole and its 2-substituted derivatives as modal analytes. Moreover, separation of fungicides, nucleobases, short peptides and sulfanilamides were achieved on ADBC-Tp@capillary. The multifunctional ADBC-Tp@capillary with satisfactory reproducibility and stability gives great promise for separation science.


Assuntos
Eletrocromatografia Capilar , Éteres de Coroa , Nanosferas , Eletrocromatografia Capilar/métodos , Imidazóis/química , Íons , Reprodutibilidade dos Testes , Espectroscopia de Infravermelho com Transformada de Fourier
9.
J Chromatogr A ; 1673: 463070, 2022 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-35526299

RESUMO

The development of novel stationary phases to achieve high-efficiency separation is still an important topic in separation sciences. Covalent organic frameworks (COFs) with the advantages of large specific surface areas, high porosity and stability have attracted great attention in chromatographic field. Here, a novel crystalline covalent organic framework (TzDa-V) was designed and synthesized by condensation reaction between 4,4',4″-(1,3,5-Triazine-2,4,6-triyl)trianiline (Tz) and 2,5-diallyloxyterephthalaldehyde (Da-V) for open-tubular capillary electrochromatography (OT-CEC). Thanks to the regular shape, strong hydrophobicity and microporous structure of COF TzDa-V, the TzDa-V modified capillary column exhibited excellent efficiency for the separation of several groups of small molecules, including alkylbenzenes, chlorobenzenes, sulfonamides and so on. The maximum column efficiency can reach about 2.0 × 105 plates•m-1 (for chlorobenzene). Besides, the prepared COF TzDa-V modified OT-column can afford methylbenzene loading capacity of 127.72 pmol. Also, the OT-columns were considerably stable and reproducible. The RSDs of intra-day (n = 3), inter-day (n = 3) and three batches runs for the retention times of four benzenes were all below 1.89%. Our successful work indicates the great potential of COF TzDa-V in CEC for high-efficiency separation.


Assuntos
Eletrocromatografia Capilar , Estruturas Metalorgânicas , Eletrocromatografia Capilar/métodos , Estruturas Metalorgânicas/química , Porosidade
10.
Appl Bionics Biomech ; 2022: 6091557, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35069799

RESUMO

This article is aimed at studying the design and implementation of a football player training management system based on smart images. Based on the analysis of the importance of informatization for scientific football training, system performance requirements and intelligent image detection technology, the football player training management is designed. The overall architecture of the system, and the detailed design of each functional module of the system. It mainly includes football player information management module, football player training plan viewing module, training goal formulation module and training information feedback module. The realization of the training management system relies on intelligent image technology to detect and track athletes. Finally, the performance of the system was tested. The test results show that the expected response time of each module of the system when different numbers of users are accessed is within 3 seconds. The longest actual time is 2.64 s, and the actual shortest time is 1.18 s. It can be seen that the response time of the system meets the demand. At the same time, the system throughput rate meets the requirements of this article, and the user pass rate is also above 95%, indicating that the performance of the football player training management system designed in this article is better.

11.
Carbohydr Polym ; 276: 118786, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34823797

RESUMO

Here, a novel multifunctional ß-cyclodextrin microporous organic network (CD-MON) has been successfully synthesized and used to remove bisphenol A (BPA) from water. The morphology and composition of the synthesized CD-MON were confirmed. The combination of hydrophobic interaction, π-π interaction inclusion mechanism and hydrogen bonding endowed CD-MON to exhibit superior adsorption capacity toward BPA. The adsorption kinetics and isotherms of BPA and other four model aromatic pollutants on CD-MON were studied. CD-MON could maintain adsorption efficiency toward BPA over wide pH ranges and without being affected by the ionic strengths, co-existing inorganic ions and humic acid. The optimal conditions and removal efficiency of BPA were screened by response surface analysis. In addition, nearly unchanged in the adsorption efficiency toward BPA was observed after five regeneration cycles on CD-MON. CD-MON can adsorb about 80% of five model aromatic pollutants from the water within 40 s in the flow-through experiments. This novel adsorbent gives great promise for practical wastewater remediation.

12.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-955473

RESUMO

Covalent organic frameworks(COFs)are a novel type of crystalline porous organic polymer materials recently developed.It has several advantages in chromatographic separation field,such as high thermal stability,porosity,structural regularity,and large specific surface area.Here,a novel spherical COF 1,3,5-tris(4-aminophenyl)benzene(TAPB)and 2,5-bis(2-propyn-1-yloxy)-1,4-benzenedicarboxaldehyde(BPTA)was developed as an electrochromatographic stationary phase for capillary electro-chromatography separation.The COFTTAPB-BPTA modified capillary column was fabricated via a facile in situ growth method at room temperature.The characterization results of scanning electron microscopy(SEM),Fourier transform infrared(FT-IR)spectroscopy,and X-ray diffraction(XRD)confirmed that COF TAPB-BPTA were successfully modified onto the capillary inner surface.The electrochromatography separation performance of the COF TAPB-BPTA modified capillary was investigated.The prepared column demonstrated outstanding separation performance toward alkylbenzenes,phenols,and chlorobenzenes compounds.Furthermore,the baseline separations of non-steroidal anti-inflammatory drugs(NSAIDs)and parabens with good efficiency and high resolution were achieved.Also,the prepared column possessed satisfactory precision of the intra-day runs(n=5),inter-day runs(n=3),and parallel columns(n=3),and the relative standard deviations(RSDs)of the retention times of tested alkylbenzenes were all less than 2.58%.Thus,this new COF-based stationary phase shows tremendous application potential in chromatographic separation field.

13.
Talanta ; 233: 122488, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34215110

RESUMO

Candida antarctica lipase B (CALB) is a natural biocatalyst with an intrinsically strong chiral environment and a high degree of enantio-selectivity, which is widely used in the separation of racemates. Here, a facile and efficient covalent immobilization approach was utilized to immobilize CALB onto the capillary inner wall as a novel chiral stationary phase to explore and broaden its application in the direct chiral separation by electrochromatography. The obtained CALB immobilized capillary column was characterized by scanning electron microscopy (SEM), fluorescence imaging and Fourier transform infrared spectroscopy (FT-IR). The enantioseparation property of the CALB immobilized capillary column was confirmed by direct chiral separation of several pairs of monoamine neurotransmitter enantiomers in OT-CEC mode. Outstanding enantioseparation performance for three types of monoamine neurotransmitter enantiomers including epinephrine, norepinephrine and phenylephrine was obtained by the CALB immobilized column. Thanks to the effectiveness of covalent bonding method and the intrinsic stability of CALB, the prepared CALB immobilized capillary columns were quite steady and reproducible. The relative standard deviations for retention times of the enantiomers were as follows: for intra-day (n = 5) runs (≤0.25%), inter-day (n = 3) runs (≤0.72%) and between-columns (n = 3) (≤2.42%). After 90 consecutive runs in CEC mode, the CALB immobilized column still exhibited desirable enantionseparation performance.


Assuntos
Eletrocromatografia Capilar , Basidiomycota , Lipase , Espectroscopia de Infravermelho com Transformada de Fourier , Estereoisomerismo
14.
J Chromatogr A ; 1649: 462239, 2021 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-34034110

RESUMO

Covalent organic frameworks (COFs), considered as a series of newly emerging porous organic materials, have been widely utilized in separation fields. Herein, a novel COF (TFPB-BD) was first employed as stationary phase for high-efficiency capillary electrochromatographic separation. Benzidine (BD) and 1,3,5-Tris-(4-formylphenyl)benzene (TFPB) were selected as organic linkers and then introduced into the aldehyde group modified capillary for the in situ growth of TFPB-BD onto the capillary inner wall at room temperature. The morphology and formation of TFPB coated capillary column were confirmed by a variety of tools including Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). It's interesting that the TFPB globular crystals with nanoscale were uniformly and densely modified on the capillary inner surface. Hence, the prepared column exhibited prominent separation performance for the test analytes including alkylbenzenes, chlorobenzenes and phenolic compounds with high efficiency and high resolution. The maximum column efficiency can reach about 1.8 × 105 plates•m-1. Additionally, the high resolutions of anilines, amino acids and parabens were also achieved on the TFPB modified capillary. The precisions (RSDs) of the retention times of alkylbenzenes of intra-day runs (n = 3), inter-day runs (n = 3) and parallel columns (n = 3) were all less than 2.83%. This innovative COF-based stationary phase gives great promise for the chromatographic separation field.


Assuntos
Eletrocromatografia Capilar/instrumentação , Estruturas Metalorgânicas/química , Microscopia Eletrônica de Varredura , Porosidade , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura
15.
J Chromatogr A ; 1647: 462166, 2021 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-33957344

RESUMO

Hydrophilic column combined with mobile phase containing high content of water is a green method for the separation of polar compounds, but there are few related studies, and the separation efficiency and performance of existing columns still needs to be improved. In this work, a novel monolithic column for separation of hydrophilic compounds under both high water content and HILIC condition, was prepared by in-situ polymerization using 4-vinylbenzoic acid (VBA) and 1-(Acryloyloxy)-3-(methacryloyloxy)-2-propanol (AMAP) as functional monomers. The poly(VBA-co-AMAP) monolithic column showed good separation performance towards various polar compounds under different chromatographic conditions based on the π-interaction, hydrophobic and hydrogen bonding interactions provided by 4-vinylbenzoic acid functional monomer. The highest column efficiency for adenine was over 2.15 × 105 plates m-1 (theoretical plate, N). In addition, the monolith showed good stability and reproducibility, the relative standard deviations (RSDs) of retention times within days (n = 5), between days (n = 5), between columns (n = 3) and between batches (n = 3) were 0.47-1.13%, 1.20-2.68%, 0.59-1.78% and 1.54-3.60%, respectively. This novel type of monolith has great application potential in the separation of hydrophilic compounds.


Assuntos
Ácido Benzoico/química , Eletrocromatografia Capilar/métodos , Adenina/análise , Adenina/química , Adenina/isolamento & purificação , Eletrocromatografia Capilar/instrumentação , Interações Hidrofóbicas e Hidrofílicas , Reprodutibilidade dos Testes , Água/química
16.
J Chromatogr A ; 1643: 462082, 2021 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-33780884

RESUMO

Herein, the fabrication of a fascinating multifunctional cyclodextrin (CD) chiral stationary phase and its chiral separation performance in capillary electrochromatography are proposed. A facile interfacial polymerization was used to anchor ethanediamine-ß-cyclodextrin (EDA-ß-CD) polymerized with trimesoyl chloride (TMC) and to form the chiral stationary phase (CSP) composite onto the surface wall of the capillary. The characters of prepared columns were confirmed by Fourier transform infrared spectroscopy (FT-IR), X-ray Photoelectron Spectrometer (XPS), scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). This novel CSP offers multi-typical interactions including hydrogen bonding, π-interaction, hydrophobic and electrostatic interaction as well as steric effects which contribute to prominent chiral recognition for Dansyl-DL-amino acids in CEC modes. The EDA-ß-CD modified column showed eminent enantioseparation performance towards five Dansyl-DL-amino acids (the DL-forms of valine, threonine, leucine, phenylalanine, serine). Besides, the prepared columns were perfectly reproducible and stable. The relative standard deviations of the enantiomer retention times for intra-day (n = 5), inter-day (n = 3) runs and column-to-columns (n = 3) are below 0.54%, 1.35% and 4.89%, individually. This innovative chiral stationary phase shows a broader application view and scope in chiral recognition domain.


Assuntos
Aminoácidos/análise , Eletrocromatografia Capilar/métodos , Compostos de Dansil/química , beta-Ciclodextrinas/química , Aminoácidos/isolamento & purificação , Compostos de Dansil/análise , Compostos de Dansil/isolamento & purificação , Etilenodiaminas/química , Leucina/análogos & derivados , Leucina/análise , Leucina/isolamento & purificação , Fenilalanina/análise , Fenilalanina/isolamento & purificação , Reprodutibilidade dos Testes , Espectroscopia de Infravermelho com Transformada de Fourier , Estereoisomerismo
17.
Micromachines (Basel) ; 12(2)2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33672013

RESUMO

In order to process micro scale parts more conveniently, especially the micro parts with complex shape, a new micro blanking equipment based on piezoelectric ceramic driving is proposed in this paper. Compared with other large precision machining equipment, the equipment cost has been greatly reduced. Using displacement sensor to detect the change of output displacement and feedback control piezoelectric actuator to control the change of relevant parameters, the control precision is high. The micro gear parts with diameter less than 2 mm are obtained through the blanking experiment on the experimental equipment. From the relationship between the obtained time and the punch output force, output displacement and die adjustment, it can be seen that the designed equipment has good processing performance and can complete the blanking forming of micro parts well.

18.
ISA Trans ; 111: 376-386, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33162061

RESUMO

Compared with single fault, the occurrence and composition of coupling faults have more uncertainties and diversities, which make fault classification a challenging topic in academic research and industrial application areas. In this paper, the classification problems of coupling faults are addressed from a new perspective, which will provide diagnostic decisions for online operators to take immediate remedial measures to bring the abnormal operation back to an incontrol state. Specifically, the main innovations are: (1) a semisupervised classification scheme for coupling faults is first proposed, which combines adaptive classification with multi-task feature selection; (2) number of classifications can be learned adaptively and automatically; (3) common and specific features among single and the associated coupling faults can be captured, which are crucial for improving classification performance. A case study on hot rolling mill process is finally given to validate the effectiveness of the proposed scheme, and several competitive methods are employed to carry out the classification process. It can be observed that the obtained classification results for two different cases are more successful than the traditional methods.

19.
J Chromatogr A ; 1629: 461497, 2020 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-32858454

RESUMO

Allylglycine, a conventional amino acid derivative, possesses typical zwitterionic and hydrophilic functionalities deriving from the carboxyl and amino groups in its structure. A novel monolithic column poly(allylglycine-co-1, 3, 5-triacryloylhexahydro-1, 3, 5-triazine) (AGly-co-TAT) with powerful hydrophilic selectivity and obvious zwitterionic feature was synthesized successfully with the monomer allyglycine and the cross-linker 1, 3, 5-triacryloylhexahydro-1, 3, 5-triazine through in-situ copolymerization for capillary electrochromatography. The obtained monolithic column has good permeability. Due to the zwitterionic functional groups of allylglycine, the poly(AGly-co-TAT) monolithic column can generate a cathodic and anodic electroosmotic flow (EOF) by changing the mobile phase pH, which is beneficial to expand its application range. The separations of different series of polar analytes, thioureas, xanthines, phenols, peptides and acidic compounds are achieved on this hydrophilic monolithic column due to the powerful hydrophilic, electrostatic and hydrogen bond interactions. Using this monolithic column, hydrophilic separations are achieved even at a lower level of 50% organic solvent. The separation efficiency up to 1.41 × 105 N m-1 and 1.19 × 105 N m-1 is achieved for the separation of theophylline and phenol, respectively. For a real sample, cytochrome C digestion, the monolithic column shows good separation performance, which offers the potential application of the monolithic column on proteomics study.


Assuntos
Eletrocromatografia Capilar/métodos , Eletro-Osmose , Glicina , Interações Hidrofóbicas e Hidrofílicas , Polímeros/química , Eletricidade Estática
20.
J Chromatogr A ; 1625: 461269, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32709321

RESUMO

Fluorous affinity means remarkably specific interaction between highly organic fluorides. This work aims to explore the potential of fluoro-functionalized stationary phase for the separation of organic fluorides by means of fluorous-fluorous interaction. Here, by using the Michael addition strategy between 1H,1H,2H,2H-perfluorodecanethiol (PFDT) and polydopamine (PD), a novel fluoro-functionalized stationary phase was synthesized for open-tubular capillary electrochromatography (OT-CEC). The PFDT@PD was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray Photoelectron Spectrometer (XPS). The PFDT@PD@capillary exhibited outstanding separation performance towards neutral compounds (such as alkylbenzenes and chlorobenzenes) and organic fluorides (such as fluorobenzenes and perfluoroalkyl methacrylates etc.) with high resolution and high separation efficiency by hydrophobic interaction and fluorous-fluorous interaction. In addition, the column shows good stability and reproducibility. The relative standard deviations (RSDs) of the retention time for intra-day (n = 5) and inter-day (n = 3) runs and between columns (n = 3) are less than 0.39%, 1.22% and 3.87%, respectively. This novel type of fluoro-functionalized stationary phase represents a great application potential in organic fluorides separation field.


Assuntos
Eletrocromatografia Capilar/métodos , Fluoretos/isolamento & purificação , Flúor/química , Compostos Orgânicos/isolamento & purificação , Eletro-Osmose , Indóis/química , Parabenos/análise , Parabenos/química , Polímeros/química , Reprodutibilidade dos Testes , Espectroscopia de Infravermelho com Transformada de Fourier
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