CONSTRUCTION AND BUILDING MATERIALS
·
2024
·
IF 7.4
Zhipeng Zhu,Xiaoxue Song,Xiang Chi,Jingyao Zhao,Qiaofang Zhou,Antoni Sanchez‑Ferrer,Dengyun Tu,Wanli Cheng
Unilateral surface compression in wood presents notable benefits, including reduced wood volume loss and energy consumption, rendering a highly promising and extensive utilization. However, shortcomings in compressed wood arise due to unclear gas pressure, temperature, and moisture content distribution within the wood during hot pressing. In this paper, the temperature and pressure distribution were analyzed utilizing an optical fiber temperature and pressure measurement system within the wood during hot pressing. Moreover, the moisture content, stress and strain in each layer at the end of hot pressing were discussed extensively. The results showed that the wood surface layer (SL) and subsurface layer (SSL) maximum temperature values were similar even with different layer thicknesses. Under sealing conditions, SL and SSL temperatures were generally 6 ℃ to 7 ℃ higher compared to unsealing conditions. The gas pressure maximum value exhibited an opposite order, gradually transferring to the core layer (CL) and declining as the processing time extended. During compression treatment, moisture migrated from the hot end to the cold within the wood. The moisture content displayed significant differences between the middle and end parts of the wood under unsealed conditions, with the disparity becoming more pronounced further away from the hot end. The transition region of the compressed wood served as a stress concentration area, experiencing the highest levels of stress. The dense region followed with the second highest stress levels, while the un-densified region exhibited the least amount of stress. Under the same process parameters, the thickness had little influence on the distribution of dense layers.
研究领域:
木材科学
·
材料科学
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES B-BIOINTERFACES
·
2020
·
IF 4.389
Jiajie Hu,Xinrui Li,Meng Li,Yazhuo Shang,Yifan He,Honglai Liu
Air pollution has become increasingly serious. Fine particulate matter (PM2.5) is the most well-known air pollutant, which leads to some common respiratory diseases when inhaled into the lungs to certain concentration. However, there is a lack of research on the process of dynamically monitoring the real-time effect of nanoparticles on the pulmonary surfactant monolayer. In this study, the DPPC/DPPG monolayer is prepared by the Langmuir method to simulate the lung surfactant monolayer during respiration and the carbon nanoparticles are introduced to the monolayer under different surface pressures to simulate the real dynamic process of inhaling nanoparticles during breathing. The effect of carbon nanoparticles on the surface behavior of DPPC/DPPG monolayer in real-time was examined in details by a combination of surface pressure (π)-area (A) isotherms, compressibility modulus ( C s - 1 )-surface pressure (π) isotherms and the Brewster angle microscopy (BAM). The results have shown that the introduction of carbon nanoparticles under different surface pressures affects the properties of lipid monolayers. The added carbon nanoparticles under lower surface pressure are easy to penetrate the lipid molecules to inhibit monolayer phase transition. When the carbon nanoparticles are introduced to the monolayer under higher surface pressure, they tend to self-aggregate to reduce the monolayer stability rather than interact with lipid tail chains. This work not only confirms the exotic hydrophobic carbon nanoparticles retain in the DPPC/DPPG monolayer irreversibly and affect the surface behavior of monolayer during respiration, but also opens a new idea for real-time monitoring of the effects of PM2.5 on lung health.
研究领域:
生物物理学
·
医学
✓ 已验证
DOI
PubMed
高影响因子
ENVIRONMENTAL POLLUTION
·
2018
·
IF 4.358
Siyang Li,Lin Du,Qingzhu Zhang,Wenxing Wang
Phthalate esters which are widely used as industrial chemicals have become widespread contaminants in the marine environment. However, little information is available on the interfacial behavior of phthalate esters in the seawater, where contaminants generally occur at elevated concentrations and have the potential to transfer into the atmosphere through wave breaking on sea surface. We used artificial seawater coated with fatty acids to simulate sea surface microlayer in a Langmuir trough. The interactions of saturated fatty acids (stearic acid (SA) and palmitic acid (PA)) with one of the most abundant phthalate esters (di-(2-ethylhexyl) phthalate (DEHP)), were investigated under artificial seawater and pure water conditions. Pure DEHP monolayer was not stable, while more stable mixed monolayers were formed by SA and DEHP on the artificial seawater at relatively low surface pressure. Sea salts in the subphase can lower the excess Gibbs free energy to form more stable mixed monolayer. Among the ten components in the sea salts, Ca 2+ ions played the major role in condensation of mixed monolayer. The condensed characteristic of the mixed SA (or PA)/DEHP monolayers suggested that the hydrocarbon chains were ordered on artificial seawater. By means of infrared reflection-absorption spectroscopy (IRRAS), we found that multiple sea salt mixtures induced deprotonated forms of fatty acids at the air–water interface. Sea salts can improve the stability and lifetime of mixed fatty acid and phthalate ester monolayer on aqueous droplets in the atmosphere. Interfacial properties of mixed fatty acid and phthalate ester monolayers at the air–ocean interface are important to help understand their behavior and fate in the marine environment.
研究领域:
环境科学
·
海洋学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACTA PHYSICO-CHIMICA SINICA
·
2016
·Vol. 32
·期 9
·2318-2326
·
IF 0.844
LIU Shan-Shan,JI Shan,CHEN Qi-Bin,PENG Chang-Jun,LIU Hong-Lai
A supramolecular polymer brush composed of polyvinylpyrrolidone-cholesterol (PVP-Chol) was fabricated based on intermolecular hydrogen bonding between the ketone groups of the PVP moieties and the hydroxyl groups of the cholesterol, both in solution and at the air/water interface. These
confirmations were confirmed by Fourier transform infrared (FT-IR) spectroscopy, surface pressure versus molecular area (π-A) isotherms, and atomic force microscopy (AFM). At surface pressures up to 2.5 mN·m-1, the interfacial film was composed of cholesterol-enriched
regions and PVP-Chol nanofibril domains. Interestingly, oversurface pressures, the structure of the PVP-Chol-enriched domains evolved frominitial irregular shapes, to crescent and heart-shaped zones, and then to circular shapes. This transition indicated the controllability of such domains
during compression of a complex monolayer at relatively low surface pressures. Above 2.5 mN·m-1, the circular PVP-Chol domains disappeared and fibrous aggregates were formed at the air/water interface. The height of the comb-like PVP-Chol nanofibrils could be reversibly varied
between approximately 4.3 and 1.8 nm by adjusting the voltage applied to piezoceramics during the AFM scanning process. These results demonstrate that the reversible structural transformation of the PVP-Chol complex from cylindrical to elliptic cylindrical is induced by the applied force of
the AFM tip up to a value of 1.0 mN·m-1. These data provide important and useful information that improves our understanding of the relationship between the structures and performances of supramolecular polymer brushes, and should extend the range of applications of cholesterol-functionalized
polymers fabricated via a simple mixing strategy.
研究领域:
材料科学
·
表面化学
·
生物材料
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2020
·
IF 3.99
Ziyan Wang,Jiwen Si,Zhenguo Song,Peng Zhang,Jian Wang,Yizhan Hao,Wenqing Li,Peiping Zhang,Shiding Miao
Froth flotation is most common means in mineral separation, and the in-situ measurement of flotation is of significance. However there were no instrumental means of measuring kinetics and thermodynamics for this process up to date. Herein, for the first time a facile method was developed by using Langmuir-Blodgett (LB) technique to get precise recording of kinetics and thermodynamics for adsorption process of Langmuir hybrid layer at the air/water interface. The formation of hybrid Langmuir monolayer was assumed to simulate the adsorption of mineral particles by frother/collector bubbles in the micro-flotation although this was a semi-static adsorption process. The kinetic parameters including time constant (τ 1/e , 32.0∼139.0 s) and adsorption rate constant (k, 0.0315∼0.00718 s −1 ) were precisely determined according to surface pressure vs. time (π-t) plots of Langmuir monolayer which consisted of floated minerals particles and collector molecules. The thermodynamic data such as partition coefficient (K d , 0.221−0.339), Gibbs free energy of adsorption ΔG (2.68∼3.74 kJ mol −1 ), and minimum dosages of collector molecules (potassium butylxanthate) were derived from the surface pressure vs. molecular area (π-A) isotherms. Taking the major mineral of pyrite with minor of dolomite and quartz as a froth flotation model, the recovery yield of concentrate pyrite obtained from LB technique was found in good agreement with the common tests used micro-flotation, suggesting the consistency of the new-developed LB method in predicting kinetics and thermodynamics for froth flotation .
研究领域:
矿物加工工程
·
界面化学
·
分离科学
·
物理化学
·
材料表面科学
✓ 已验证
DOI
高影响因子
Environmental Science-Processes & Impacts
·
2018
·Vol. 20
·期 11
·1500-1511
·
IF 2.491
Junyao Li,Siyang Li,Shumin Cheng,Narcisse T. Tsona,Lin Du
Mixed Langmuir monolayers of cholesterol with both saturated and unsaturated fatty acids, stearic acid (SA), and oleic acid (OA) spread at the air–seawater surface were studied. The phase behavior, molecular interaction, and conformational order of the monolayers were investigated by surface pressure–area (π–A) isotherms and infrared reflection-absorption spectroscopy (IRRAS) measurements. The thermodynamic parameters of the mixed films, including excess molecular area and excess Gibbs free energy were calculated by using the isotherm data. The interaction between SA (or OA) and cholesterol varied with the molar fraction of the fatty acids and surface pressure. OA/chol monolayers showed the characteristics of miscibility, but they acted as nonideal systems. Cholesterol has been observed to have a stabilizing effect on OA monolayers. The negative values of the excess Gibbs free energy in the entire composition range demonstrated that mixed OA/chol monolayers were thermodynamically stable. IRRAS spectra showed that mixing with cholesterol changes the ordering of fatty acid monolayers at the air–seawater surface. The findings provide general information regarding the structural changes in the monolayer induced by lateral packing. These results help in the understanding of the mixing behavior of fatty acids and cholesterol and provide insights into the fate of the mixed-monolayer-coated sea salt aerosol in the ocean environment.
研究领域:
生物医学工程
·
环境科学
·
表面化学
·
材料科学
·
大气物理学
·
物理化学
✓ 已验证
DOI
高影响因子
FOOD HYDROCOLLOIDS
·
2019
·
IF 5.839
Lechuan Wang,Lisha Li,Nuo Xu,Weiqing Sun,Baomiao Ding,Wei Xu,Zhenshun Li
Lysozyme (Ly), as an important natural preservative, easily interacts with anionic polysaccharides in food , which results in low and unstable bacteriostatic activity. The interaction of carboxymethylcellulose (CMC) with Ly was used to investigate the mechanism of the bioactivity changes caused by Ly binding polysaccharides. The affinity of Ly or Ly-CMC complexes for a mixed monolayer liposome (Lip) as an in vitro biomembrane model was characterized by using dynamic light scattering, Fourier transform infrared spectroscopy , circular dichroism spectroscopy , fluorescence analysis and interface activity measurements. The results showed that the affinity between Ly and Lip mainly depended on hydrophobic and electrostatic forces. The electrostatic interaction in Ly-CMC weakened the Ly-Lip affinity and altered the spatial conformation of Ly molecules. Furthermore, CMC screened the active sites of Ly and neutralized the charge of Ly, which may reduce its bioactivity. The presence of CMC decreased the increase in surface pressure in the Lip-Ly interface, which means that Ly-CMC has a lower insertion capacity and ability to induce lipid molecule rearrangement than Ly alone, indicating an inferior bacteriostatic ability. Our work explains how the bacteriostatic mechanism of Ly is affected by food biopolymers.
研究领域:
食品科学
·
生物化学
·
生物物理学
✓ 已验证
产品关联
DOI
高影响因子
CHEMOSPHERE
·
2021
·
IF 7.086
Yan Cao,Linfeng Zhang,Yingxue Geng,Yingjie Li,Qun Zhao,Jianhong Huang,Ping Ning,Senlin Tian
Polycyclic aromatic hydrocarbons (PAHs) can penetrate and accumulate in the pulmonary surfactant (PS) membranes, leading to abnormalities of biological macromolecules and the destruction of membrane structure and properties. In the present study, the bioavailability , apparent permeability, effective permeability and residual coefficient of 10 PAHs on PS membrane was assessed by the parallel artificial membrane permeability assay (PAMPA). The influence of various forces on permeability is obtained by analyzing the correlation between parameters and physicochemical properties . Research shows that octanol-water partition coefficient ( K ow ) cannot directly predict permeability, and permeability has no significant relationship with polarity. Dispersion, induction, coupling/polarization promote permeation, while hydrogen bonded acid and n-n electron pair inhibit permeation. Further surface pressure-area (π-A) isotherms test and Brewster angle microscope observation manifested that there are huge differences in the transmembrane ability and effects on the membrane of PAHs with different structures. This work has considerable significance that will help to evaluate the bioavailability and human health risk of PAHs.
研究领域:
环境科学
·
毒理学
·
生物物理学
·
化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）