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Electronic and mechanical responses of two-dimensional HfS

Mohammad SALAVATI

《结构与土木工程前沿(英文)》 2019年 第13卷 第2期   页码 486-494 doi: 10.1007/s11709-018-0491-5

摘要: During the last decade, numerous high-quality two-dimensional (2D) materials with semiconducting electronic character have been synthesized. Recent experimental study (Sci. Adv. 2017;3: e1700481) nevertheless confirmed that 2D ZrSe and HfSe are among the best candidates to replace the silicon in nanoelectronics owing to their moderate band-gap. We accordingly conducted first-principles calculations to explore the mechanical and electronic responses of not only ZrSe and HfSe , but also ZrS and HfS in their single-layer and free-standing form. We particularly studied the possibility of engineering of the electronic properties of these attractive 2D materials using the biaxial or uniaxial tensile loadings. The comprehensive insight provided concerning the intrinsic properties of HfS , HfSe , ZrS , and ZrSe can be useful for their future applications in nanodevices.

关键词: 2D materials     mechanical     electronic     DFT    

Interlayer-confined two-dimensional manganese oxide-carbon nanotube catalytic ozonation membrane for

《化学科学与工程前沿(英文)》 2022年 第16卷 第5期   页码 731-744 doi: 10.1007/s11705-021-2110-6

摘要: Catalytic ozonation technology has attracted copious attention in water purification owing to its favorable oxidative degradation of pollutants and mitigation of membrane fouling capacity. However, its extensive industrial application has been restricted by the low ozone utilization and limited mass transfer of the short-lived radical species. Interlayer space-confined catalysis has been theoretically proven to be a viable strategy for achieving high catalytic efficiency. Here, a two-dimensional MnO2-incorporated ceramic membrane with tunable interspacing, which was obtained via the intercalation of a carbon nanotube, was designed as a catalytic ozonation membrane reactor for degrading methylene blue. Benefiting from the abundant catalytic active sites on the surface of two-dimensional MnO2 as well as the ultralow mass transfer resistance of fluids due to the nanolayer confinement, an excellent mineralization effect, i.e., 1.2 mg O3(aq) mg–1 TOC removal (a total organic carbon removal rate of 71.5%), was achieved within a hydraulic retention time of 0.045 s of pollutant degradation. Further, the effects of hydraulic retention time and interlayer spacing on methylene blue removal were investigated. Moreover, the mechanism of the catalytic ozonation employing catalytic ozonation membrane was proposed based on the contribution of the Mn(III/IV) redox pair to electron transfer to generate the reactive oxygen species. This innovative two-dimensional confinement catalytic ozonation membrane could act as a nanoreactor and separator to efficiently oxidize organic pollutants and enhance the control of membrane fouling during water purification.

关键词: catalytic membrane reactor     catalytic ozonation     nanoconfinement     two-dimensional manganese oxide    

Numerical simulation of two-dimensional spouted bed with draft plates by discrete element method

ZHAO Yongzhi, JIANG Maoqiang, CHENG Yi, JIN Yong

《化学科学与工程前沿(英文)》 2008年 第2卷 第1期   页码 5-9 doi: 10.1007/s11705-008-0009-0

摘要: A discrete element method (DEM)-computational fluid dynamics (CFD) two-way coupling method was employed to simulate the hydrodynamics in a two-dimensional spouted bed with draft plates. The motion of particles was modeled by the DEM and the gas flow was modeled by the Navier-Stokes equation. The interactions between gas and particles were considered using a two-way coupling method. The motion of particles in the spouted bed with complex geometry was solved by combining DEM and boundary element method (BEM). The minimal spouted velocity was obtained by the BEM-DEM-CFD simulation and the variation of the flow pattern in the bed with different superficial gas velocity was studied. The relationship between the pressure drop of the spouted bed and the superficial gas velocity was achieved from the simulations. The radial profile of the averaged vertical velocities of particles and the profile of the averaged void fraction in the spout and the annulus were statistically analyzed. The flow characteristics of the gas-solid system in the two-dimensional spouted bed were clearly described by the simulation results.

关键词: annulus     BEM-DEM-CFD simulation     gas-solid     two-dimensional     relationship    

Shape/size controlling syntheses, properties and applications of two-dimensional noble metal nanocrystals

Baozhen An,Mingjie Li,Jialin Wang,Chaoxu Li

《化学科学与工程前沿(英文)》 2016年 第10卷 第3期   页码 360-382 doi: 10.1007/s11705-016-1576-0

摘要: Two dimensional (2D) nanocrystals of noble metals (e.g., Au, Ag, Pt) often have unique structural and environmental properties which make them useful for applications in electronics, optics, sensors and biomedicines. In recent years, there has been a focus on discovering the fundamental mechanisms which govern the synthesis of the diverse geometries of these 2D metal nanocrystals (e.g., shapes, thickness, and lateral sizes). This has resulted in being able to better control the properties of these 2D structures for specific applications. In this review, a brief historical survey of the intrinsic anisotropic properties and quantum size effects of 2D noble metal nanocrystals is given and then a summary of synthetic approaches to control their shapes and sizes is presented. The unique properties and fascinating applications of these nanocrystals are also discussed.

关键词: two-dimension     noble metal     nanocrystal     surface plasmon     controllable synthesis    

Toughening of vinyl ester resins by two-dimensional MXene nanosheets

《化学科学与工程前沿(英文)》   页码 1651-1658 doi: 10.1007/s11705-022-2208-5

摘要: Two-dimensional nanosheets are highly effective tougheners for vinyl ester resins. The toughening effect is related to the high specific surface area and unique two-dimensional planar structure of the nanosheets. In this study, a coupling agent γ-(2,3-epoxypropoxy) propytrimethoxysilane (Kh-560) was used to modify MXene nanosheets (M-MXene) for use in toughening vinyl ester resin. The mechanical properties, including the tensile strength, flexural strength, Young’s modulus and elongation, of neat vinyl ester resin and vinyl ester resin modified with MXene and M-MXene were investigated. The results showed that modification significantly improved the mechanical properties of the vinyl ester resin. The tensile and flexural strengths of the MXene-nanosheet-modified vinyl ester resin were 27.20% and 25.32% higher, respectively, than those of the neat vinyl ester resin. The coupling agent improved the interfacial compatibility between the MXene nanosheets and vinyl ester resin, which resulted in the tensile and flexural strengths of the M-MXene-nanosheet-modified vinyl ester resin being 52.57% and 54.60% higher, respectively, than those of the neat vinyl ester resin for a loading quantity of nanosheets of only 0.04 wt %, which is economically viable. The main mechanisms by which the nanosheets toughen the resin are crack deflection and crack pinning.

关键词: MXene nanosheets     2D material     vinyl ester resin     modification     coupling agent    

Protein adsorption in two-dimensional electrochromatography packed with superporous and microporous cellulose

Dongmei WANG, Guodong JIA, Liang XU, Xiaoyan DONG, Yan SUN

《化学科学与工程前沿(英文)》 2009年 第3卷 第3期   页码 229-234 doi: 10.1007/s11705-009-0213-6

摘要: Anion-exchange superporous cellulose (DEAE-SC) and microporous cellulose (DEAE-MC) adsorbents were packed in an electrochromatographic column, and the effect of external electric field (eEF) on the dynamic adsorption was investigated. The column was designed to provide longitudinal, transverse or 2-dimensional (2D) eEF. It was found that the electro-kinetic effect caused by the introduction of an electric field played an important role in the dynamic adsorption of bovine serum albumin to the adsorbents. The dynamic binding capacity (DBC) in the presence of 2D eEF was higher than in the presence of a one-dimensional eEF. The effect of flow velocity on the DBC of the two adsorbents was also demonstrated. It was found that the effect of electric field on the DEAE-MC column was more remarkable than that on the DEAE-SC column at the same flow rate, whereas the DEAE-SC column showed higher DBC and adsorption efficiency (AE) than the DEAE-MC column. With increasing flow rate, the DEAE-SC column could still offer high DBC and AE in the presence of the 2D eEF. For example, a DBC of 21.4 mg/mL and an AE of 57.7% were obtained even at a flow rate as high as 900 cm/h. The results indicate that the 2D electrochromatography packed with the superporous cellulose adsorbent is promising for high-speed protein chromatography.

关键词: electrochromatography     two-dimensional electric field     dynamic binding capacity     superporous cellulose bead     protein    

Remediation of 2,4-dichlorophenol-contaminated groundwater using nano-sized CaO in a two-dimensional

《环境科学与工程前沿(英文)》 2020年 第15卷 第5期 doi: 10.1007/s11783-020-1381-3

摘要:

• Nano CaO2 is evaluated as a remediation agent for 2,4-DCP contaminated groundwater.

关键词: Calcium peroxide     2     4-DCP     Reaction zone     Fenton reaction    

A DNA sensor based on upconversion nanoparticles and two-dimensional dichalcogenide materials

Konstantina Alexaki, Davide Giust, Maria-Eleni Kyriazi, Afaf H. El-Sagheer, Tom Brown, Otto L. Muskens, Antonios G. Kanaras

《化学科学与工程前沿(英文)》 2021年 第15卷 第4期   页码 935-943 doi: 10.1007/s11705-020-2023-9

摘要: We demonstrate the fabrication of a new DNA sensor that is based on the optical interactions occurring between oligonucleotide-coated NaYF : Yb ; Er upconversion nanoparticles and the two-dimensional dichalcogenide materials, MoS and WS . Monodisperse upconversion nanoparticles were functionalized with single-stranded DNA endowing the nanoparticles with the ability to interact with the surface of the two-dimensional materials via van der Waals interactions leading to subsequent quenching of the upconversion fluorescence. By contrast, in the presence of a complementary oligonucleotide target and the formation of double-stranded DNA, the upconversion nanoparticles could not interact with MoS and WS , thus retaining their inherent fluorescence properties. Utilizing this sensor we were able to detect target oligonucleotides with high sensitivity and specificity whilst reaching a concentration detection limit as low as 5 fmol·L , within minutes.

关键词: upconversion nanoparticles     DNA sensor     two-dimensional materials     MoS2     WS2    

A two-dimensional numerical model for eutrophication in Baiyangdian Lake

Xudong WANG, Shushen ZHANG, Suling LIU, Jingwen CHEN

《环境科学与工程前沿(英文)》 2012年 第6卷 第6期   页码 815-824 doi: 10.1007/s11783-011-0383-6

摘要: Hydrodynamic, physical, and biochemical processes in the Baiyangdian Lake water environment were analyzed comprehensively. An eutrophication eco-dynamics model including the effects of reed resistance on flow was coupled with the hydrodynamics governing equations. An improvement on the Water Quality Analysis Simulation Program (WASP, a modeling system introduced by the US Environmental Protection Agency) is established, which uses the zooplankton kinetic equation. The model simulates water quality constituents associated with eutrophication in the lake, including phytoplankton, zooplankton, nitrogen, phosphorus, dissolved oxygen, and others. Various kinetic coefficients were calibrated using measured data or information from relevant literature, to study eutrophication in the lake. The values calculated by the calibrated model agree well with field data, including ammonia nitrogen, total nitrogen, total phosphorus and dissolved oxygen. Changes related to nutrition and dissolved oxygen during the processes were simulated. The present model describes the temporal variation of water quality in Baiyangdian Lake with reasonable accuracy. Deviations between model-simulated and observed values are discussed. As an ideal tool for environmental management of the lake, this model can be used to predict its water quality, and be used in research to examine the eutrophication process.

关键词: eutrophication     eco-dynamics     hydrodynamics     improved Water Quality Analysis Simulation Program (WASP) model     Baiyangdian Lake    

Numerical investigation of circle defining curve for two-dimensional problem with general boundaries

Chung Nguyen VAN

《结构与土木工程前沿(英文)》 2019年 第13卷 第1期   页码 92-102 doi: 10.1007/s11709-018-0472-8

摘要: The scaled boundary finite element method (SBFEM) is applied to the static analysis of two dimensional elasticity problem, boundary value problems domain with the domain completely described by a circular defining curve. The scaled boundary finite element equations is formulated within a general framework integrating the influence of the distributed body force, general boundary conditions, and bounded and unbounded domain. This paper investigates the possibility of using exact geometry to form the exact description of the circular defining curve and the standard finite element shape function to approximate the defining curve. Three linear elasticity problems are presented to verify the proposed method with the analytical solution. Numerical examples show the accuracy and efficiency of the proposed method, and the performance is found to be better than using standard linear element for the approximation defining curve on the scaled boundary method.

关键词: exact geometry     circular defining curve     general boundaries     SBFEM    

Size effects in two-dimensional layered materials modeled by couple stress elasticity

Wipavee WONGVIBOONSIN, Panos GOURGIOTIS, Chung Nguyen VAN, Suchart LIMKATANYU, Jaroon RUNGAMORNRAT

《结构与土木工程前沿(英文)》 2021年 第15卷 第2期   页码 425-443 doi: 10.1007/s11709-021-0707-y

摘要: In the present study, the effect of material microstructure on the mechanical response of a two-dimensional elastic layer perfectly bonded to a substrate is examined under surface loadings. In the current model, the substrate is treated as an elastic half plane as opposed to a rigid base, and this enables its applications in practical cases when the modulus of the layer (e.g., the coating material) and substrate (e.g., the coated surface) are comparable. The material microstructure is modeled using the generalized continuum theory of couple stress elasticity. The boundary value problems are formulated in terms of the displacement field and solved in an analytical manner via the Fourier transform and stiffness matrix method. The results demonstrate the capability of the present continuum theory to efficiently model the size-dependency of the response of the material when the external and internal length scales are comparable. Furthermore, the results indicated that the material mismatch and substrate stiffness play a crucial role in the predicted elastic field. Specifically, the study also addresses significant discrepancy of the response for the case of a layer resting on a rigid substrate.

关键词: cosserat     layered materials     size effects     microstructure    

Three-dimensional stability analysis of the dam foundation at Baise

XU Qianjun, LI Xu, CHEN Zuyu

《结构与土木工程前沿(英文)》 2007年 第1卷 第2期   页码 217-221 doi: 10.1007/s11709-007-0026-y

摘要: It is usually difficult to determine the actual safety factors of rock masses in an ordinary two-dimensional stability analysis if the safety factors of the different cross sections in the rock mass vary significantly. In addition to the actual slope, arch dam abutment, and the actual foundation of a high building, another example is that the different cross sections of the foundation in the monolith of a gravity dam vary significantly, just like the condition at the overflow dam in the Baise project. A three-dimensional stability analysis method based on the upper-bound theorem was employed to solve this problem. The parameters used in the analysis were obtained from geomechanics tests, as well as continuity simulations of the randomly distributed joints. Two failure patterns against sliding are analyzed. One pattern is the foundation slide along deep-seated planes which were determined by calculations. The other pattern is the foundation slide along the planes across the bottom of the high steps in the foundation pit. The results indicate that a special overflow dam monolith can be considered to be safe in case of considering the three dimensional effect. However, a key wall with a depth of 5m must be constructed at the upper side of this monolith in order to ensure the safety of the foundation.

关键词: ordinary two-dimensional     randomly     monolith     three-dimensional stability     different    

Scaled boundary finite element method with exact defining curves for two-dimensional linear multi-field

Jaroon RUNGAMORNRAT, Chung Nguyen VAN

《结构与土木工程前沿(英文)》 2019年 第13卷 第1期   页码 201-214 doi: 10.1007/s11709-018-0488-0

摘要: This paper presents an efficient and accurate numerical technique based upon the scaled boundary finite element method for the analysis of two-dimensional, linear, second-order, boundary value problems with a domain completely described by a circular defining curve. The scaled boundary finite element formulation is established in a general framework allowing single-field and multi-field problems, bounded and unbounded bodies, distributed body source, and general boundary conditions to be treated in a unified fashion. The conventional polar coordinates together with a properly selected scaling center are utilized to achieve the exact description of the circular defining curve, exact geometry of the domain, and exact spatial differential operators. Standard finite element shape functions are employed in the discretization of both trial and test functions in the circumferential direction and the resulting eigenproblem is solved by a selected efficient algorithm. The computational performance of the implemented procedure is then fully investigated for various scenarios to demonstrate the accuracy in comparison with standard linear elements.

关键词: multi-field problems     defining curve     exact geometry     general boundary conditions     SBFEM    

Recent progress of two-dimensional nanosheet membranes and composite membranes for separation applications

Wei Wang, Yanying Wei, Jiang Fan, Jiahao Cai, Zong Lu, Li Ding, Haihui Wang

《化学科学与工程前沿(英文)》 2021年 第15卷 第4期   页码 793-819 doi: 10.1007/s11705-020-2016-8

摘要: Two-dimensional (2D) materials have emerged as a class of promising materials to prepare high-performance 2D membranes for various separation applications. The precise control of the interlayer nanochannel/sub-nanochannel between nanosheets or the pore size of nanosheets within 2D membranes enables 2D membranes to achieve promising molecular sieving performance. To date, many 2D membranes with high permeability and high selectivity have been reported, exhibiting high separation performance. This review presents the development, progress, and recent breakthrough of different types of 2D membranes, including membranes based on porous and non-porous 2D nanosheets for various separations. Separation mechanism of 2D membranes and their fabrication methods are also reviewed. Last but not the least, challenges and future directions of 2D membranes for wide utilization are discussed in brief.

关键词: membrane separation     2D membranes     2D materials     nanosheet    

基于模糊集理论的二维线性鉴别分析新方法

郑宇杰,杨静宇,吴小俊,李勇智

《中国工程科学》 2007年 第9卷 第2期   页码 49-53

摘要:

二维线性鉴别分析(2DLDA)是一种直接基于矩阵的特征提取方法,跳过传统的基于Fisher鉴别准则 的线性鉴别分析方法中必须先将二维矩阵转化成一维矢量的过程,有效地提高了特征提取速度且避免了小样本问题,其识别率优于传统的Fisherface方法。结合模糊集理论,提出了一种新的2DLDA算法——模糊2DLDA (F1DLDA)算法。首先采用FKNN算法得到相应的样本分布信息,并按其对最后得到的特征向量所作的贡献融入 到特征抽取过程中,得到有效的样本特征向量集。实验表明,F2DLDA算法的性能优于传统的2DLDA算法和Fisherface算法。

关键词: 二维线性鉴别分析     模糊二维线性鉴别分析     模糊集理论     特征提取     模糊k近邻    

标题 作者 时间 类型 操作

Electronic and mechanical responses of two-dimensional HfS

Mohammad SALAVATI

期刊论文

Interlayer-confined two-dimensional manganese oxide-carbon nanotube catalytic ozonation membrane for

期刊论文

Numerical simulation of two-dimensional spouted bed with draft plates by discrete element method

ZHAO Yongzhi, JIANG Maoqiang, CHENG Yi, JIN Yong

期刊论文

Shape/size controlling syntheses, properties and applications of two-dimensional noble metal nanocrystals

Baozhen An,Mingjie Li,Jialin Wang,Chaoxu Li

期刊论文

Toughening of vinyl ester resins by two-dimensional MXene nanosheets

期刊论文

Protein adsorption in two-dimensional electrochromatography packed with superporous and microporous cellulose

Dongmei WANG, Guodong JIA, Liang XU, Xiaoyan DONG, Yan SUN

期刊论文

Remediation of 2,4-dichlorophenol-contaminated groundwater using nano-sized CaO in a two-dimensional

期刊论文

A DNA sensor based on upconversion nanoparticles and two-dimensional dichalcogenide materials

Konstantina Alexaki, Davide Giust, Maria-Eleni Kyriazi, Afaf H. El-Sagheer, Tom Brown, Otto L. Muskens, Antonios G. Kanaras

期刊论文

A two-dimensional numerical model for eutrophication in Baiyangdian Lake

Xudong WANG, Shushen ZHANG, Suling LIU, Jingwen CHEN

期刊论文

Numerical investigation of circle defining curve for two-dimensional problem with general boundaries

Chung Nguyen VAN

期刊论文

Size effects in two-dimensional layered materials modeled by couple stress elasticity

Wipavee WONGVIBOONSIN, Panos GOURGIOTIS, Chung Nguyen VAN, Suchart LIMKATANYU, Jaroon RUNGAMORNRAT

期刊论文

Three-dimensional stability analysis of the dam foundation at Baise

XU Qianjun, LI Xu, CHEN Zuyu

期刊论文

Scaled boundary finite element method with exact defining curves for two-dimensional linear multi-field

Jaroon RUNGAMORNRAT, Chung Nguyen VAN

期刊论文

Recent progress of two-dimensional nanosheet membranes and composite membranes for separation applications

Wei Wang, Yanying Wei, Jiang Fan, Jiahao Cai, Zong Lu, Li Ding, Haihui Wang

期刊论文

基于模糊集理论的二维线性鉴别分析新方法

郑宇杰,杨静宇,吴小俊,李勇智

期刊论文