COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2017
·
IF 2.714
Zhilin Xi,Zhenya Feng,Ang Li
For the control of pulverized coal, we propose a dust suppressant by applying a blend of mixed polyethylene oxide (g-PEO) and sodium dodecyl sulfate ( SDS ). In our experimental study, the thermal characteristics, critical micelle concentration ( CMC ), wettability and adhesion of the dust suppressant are investigated. It was found that g-PEO had a low fusing temperature and its combustion temperature was close to that of coal, thus, the solution containing g-PEO applied coal dust control did not affect the use of the coal. Based on steady-state fluorescence using pyrene as a fluorescent label, quantitative analysis revealed that the CMC s of g-PEO and SDS were 1 and 20 g/L in g-PEO& SDS solution, respectively. The solution containing SDS had the best wettability, but it only had a short-term effect. The solution containing g-PEO showed negligible wetting ability to wet coal dust. The solution containing g-PEO& SDS had better wetting ability and adhesion. Scanning electron microscopy showed that the coal dust covered by g-PEO& SDS on its surface could form a thin layer of armor by holding the particles together after air-drying. It was concluded that the g-PEO& SDS solution containing g-PEO for 1 g/L and SDS for 20 g/L could suppress coal dust and maintain a long-term effect.
研究领域:
环境工程
·
矿业安全
·
颗粒物控制
·
表面化学
·
燃烧科学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2022
·Vol. 47
·期 79
·33861-33871
·
IF 7.139
Zhizhong Leng,Zuzhi Huang,Xu Zhou,Bo Zhang,Hu Bai,Juan Zhou,Shaorong Wang
Proton-conducting solid oxide electrolysis cells (H-SOECs) are attracting attentions of researchers due to their unique advantages. The proton-conducting material BaCe 0·7 Zr 0·1 Y 0.1 Yb 0.1 O 3-δ (BZCYYb) has both the advantages of barium ceria-based and barium zirconate-based materials. BZCYYb material usually is synthesized by solid-state reaction (SSR) method, hence the densification of this electrolyte material is the key to restrict the application of H-SOECs. In this paper, effects of adding 1 wt% of different sintering aids (NiO, CuO, ZnO) to BZCYYb on the grain size and the conductivity are investigated. After adding 1 wt% of NiO and CuO sintering aids, BZCYYb electrolyte achieves ideal density. The electrical conductivity of four samples (BZCYYb without adding sintering aid, BZCYYb with 1 wt% NiO, CuO, ZnO, respectively) is tested under different steam concentrations of air, nitrogen, hydrogen, and nitrogen-hydrogen mixture. The conductivity increased after the sintering aid is added. With the increase of steam concentration, the conductivity decreased slightly and then increased due to electron holes under oxygen atmosphere with steam at high temperature. In other atmospheres, the conductivity increases with the steam concentration. In the atmosphere of 20 vol% H 2 O-Air and H 2 , the conductivity of the BZCYYb samples with 1 wt% CuO is about 1.087 × 10 −2 S cm −1 and 9.02 × 10 −3 S cm −1 at 650 °C, and the conductivity of the BZCYYb samples with 1 wt% NiO is 1.277 × 10 −2 S cm −1 and 8.24 × 10 −3 S cm −1 , respectively. However, compared with NiO, CuO has advantages in promoting hydration reaction and proton conduction of BZCYYb electrolyte.
研究领域:
材料科学
·
电化学
·
能源材料
·
固态离子学
·
陶瓷材料
✓ 已验证
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2020
·
IF 9.038
Chuyuan Huang,Xianfeng Chen,Bihe Yuan,Hongming Zhang,Sheng Shang,Qi Zhao,Huaming Dai,Song He,Ying Zhang,Yi Niu
Flame propagation characteristics of wood dust deflagration and suppression mechanism of ultrafine powders are investigated systematically. The deflagration reaction intensity of wood dust increases firstly and then decreases with the increase in dust cloud concentration. This is due to factors such as oxygen supply, positive feedback among flame characteristic parameters. Thus, there is an equivalent dust concentration for greatest deflagration intensity. Nano-sized ultrafine zirconium hydroxide (Zr(OH) 4 ) and silicon dioxide (SiO 2 ) powder are introduced to suppress wood dust deflagration at the equivalent concentration. It is found that Zr(OH) 4 has a suppression effect of endothermic decomposition to generate zirconia (ZrO 2 ), dilution of oxygen and absorption of free radicals; while SiO 2 exerts suppression effect due to its high melting point and heat absorption. The suppression performance of Zr(OH) 4 is better than that of SiO 2 . This is because that Zr(OH) 4 and ZrO 2 have a catalytic carbonization effect. It can not only improve thermal stability of wood particles by catalyzing production of high-temperature resistant residuals, but also promote the formation of catalytic sites to reduce crystallite size of carbon layer on wood particles surface, weakening heat and mass transfer between particles.
研究领域:
安全工程
·
燃烧学
·
粉尘爆炸防控
·
材料化学
·
热力学
✓ 已验证
DOI
高影响因子
Journal of Global Antimicrobial Resistance
·
2016
·
IF 1.087
Dongmei Wu,Ruochen Lu,Yuquan Chen,Jie Qiu,Chaocheng Deng,Qiang Tan
This study aimed to determine whether selection by antibiotics, chlorhexidine (CHX) and Rhizoma coptidis extract (RCE) would lead to cross-resistance or decreased susceptibility in Staphylococcus aureus . The S. aureus reference strain ATCC 25923 as well as 14 clinical isolates were exposed to antibiotics, CHX and RCE at sublethal doses for up to 14 days. Changes in susceptibility were determined by analysis of minimum inhibitory concentrations (MICs). All isolates were cross-resistant to more than one other antibiotic following tetracycline exposure, and increased resistance (≥4-fold MIC increase) to RCE and CHX was observed in six and three isolates, respectively. Following selection by CHX, most of the treated strains showed no significant change in sensitivity to CHX. However, all strains developed cross-resistance to at least one antibiotic, and decreased susceptibility (≥4-fold MIC increase) to RCE appeared in seven strains. Following exposure to RCE, 11 isolates showed cross-resistance to at least one antibiotic. In addition, three RCE-exposed strains showed reduced susceptibility to CHX (4- or 8-fold MIC increase). The results obtained in this study imply that antibiotics, biocides and antimicrobial Chinese herbs might employ some of the same mechanisms of action against bacteria, triggering mutual cross-resistance to further foster the development of bacterial resistance.
研究领域:
微生物学
·
感染病学
·
药理学
·
分子生物学
·
抗菌药物耐药性
·
天然药物学
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2014
·
IF 2.354
Ni Cheng,Xiaoyuan Ma,Xiang Sheng,Tao Wang,Rui Wang,Jingjing Jiao,Li Yu
Two structurally similar imidazolium-based anionic surface active ionic liquids (SAILs) with double hydrocarbon chains, viz. 1-butyl-3-methylimidazolium bis(2-ethylhexyl) sulfosuccinate (C 4 mim-AOT) and 1-butyl-3-methylimidazolium bis(2-ethylhexyl) phosphate (C 4 mim-DEHP), were synthesized by a straightforward ion-exchange technique. A comparative investigation of their aggregation behavior with the corresponding traditional anionic surfactants, sodium bis(2-ethylhexyl) sulfosuccinate (Na-AOT) and sodium bis(2-ethylhexyl) phosphate (Na-DEHP) in aqueous solution was performed in detail by surface tension, electric conductivity, fluorescence spectra and dynamic light scattering measurements. The critical micelle concentration (CMC) values for the surfactants with double hydrocarbon chains obtained by different techniques are in good agreement. The surface activity of C 4 mim-AOT and C 4 mim-DEHP is superior to that of the corresponding traditional anionic surfactants, Na-AOT and Na-DEHP. It is also found that for anionic SAILs the nature of the anionic active group is a dominant factor in the determination of their aggregation behavior in aqueous solution, e.g. CMC and aggregation number, while the introduced organic cation plays a minor role. Theoretical calculations show that more conformations and electronegativity for DEHP anion leads to higher aggregation number and CMC values for C 4 mim-DEHP. This work is expected to be of practical values for the environmental friendly anion SAILs in nanomaterial synthesis and phase separation, etc.
研究领域:
物理化学
·
胶体与界面化学
·
纳米材料合成
·
环境友好材料
·
分子自组装
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2018
·
IF 3.779
Nan Liu,Zhi Dong,Zongqing Ma,Liming Yu,Chong Li,Chenxi Liu,Qianying Guo,Yongchang Liu
The bimodal distribution of tungsten grain size, which is also called bimodal structure, is a universal phenomenon in synthesizing tungsten based nanopowders by wet chemical method , and could significantly deteriorate further sintering characteristics of the powders. In this paper, W-Y 2 O 3 composite nanopowders with small grain size and no bimodal structure were synthesized by an improved wet chemical method. It was found that reaction conditions, especially the hydrogen ion concentration(ρ(H + )) could significantly influence the microstructure and morphology of the prepared composite nanopowders and has an optimum value of approximately 0.16 mol L −1 . W-Y 2 O 3 composite nanopowders synthesized under this optimum value got not only the minimum average grain size, which is about 17 nm, but also the best grain size uniformity with no bimodal structure. The microstructure of co-deposited precursors and prepared powders was analyzed in detail to figure out the specific influence mechanism of ρ(H + ), and it was indicated that ρ(H + ) could influence the microstructure and the Y 2 O 3 content of the reduced powders through affecting the fraction of precursor that has little yttrium content, which may lead to the bimodal distribution of tungsten grain size of the prepared powders. Furthermore, the formation mechanism of bimodal structure was systematically analyzed and a feasible method was proposed to eliminate the bimodal structure. It is suggested that the bimodal distribution of tungsten grain size is attributed to the distribution of Y 2 O 3 during hydrogen reduction process and can be well avoided by controlling ρ(H + ).
研究领域:
材料科学
·
纳米材料
·
粉末冶金
·
无机非金属材料
·
功能材料
✓ 已验证
DOI
高影响因子
Small
·
2023
·Vol. 20
·期 3
·2306251
·
IF 13.3
Muchun Guo,Ming Liu,Jianbo Zhu,Yuke Zhu,Fengkai Guo,Wei Cai,Yongsheng Zhang,QinYong Zhang,Jiehe Sui
Chemical bonds determine electron and phonon transport in solids. Tailoring chemical bonding in thermoelectric materials causes desirable or compromise thermoelectric transport properties. In this work, taking an example of CaMg 2 Bi 2 with covalent and ionic bonds, density functional theory calculations uncover that element Zn, respectively, replacing Ca and Mg sites cause the weakness of ionic and covalent bonding. Electrically, Zn doping at both Ca and Mg sites increases carrier concentration, while the former leads to higher carrier concentration than that of the latter because of its lower vacancy formation energy. Both doping types increase density-of-state effective mass but their mechanisms are different. The Zn doping Ca site induces resonance level in valence band and Zn doping Mg site promotes orbital alignment. Thermally, point defect and the change of phonon dispersion introduced by doping result in pronounced reduction of lattice thermal conductivity. Finally, combining with the further increase of carrier concentration caused by Na doping and the modulation of band structure and the decrease of lattice thermal conductivity caused by Ba doping, a high figure-of-merit ZT of 1.1 at 823 K in Zn doping Ca sample is realized, which is competitive in 1–2–2 Zintl phase thermoelectric systems.
研究领域:
材料科学
·
凝聚态物理
·
无机化学
·
能源材料
·
热电转换
✓ 已验证
DOI
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2017
·
IF 3.181
Xinyan Yan,Zhaolan Zhai,Zhanqian Song,Shibin Shang,Xiaoping Rao
A series of polymeric surfactants , poly acrylic acid rosin polyethylene glycol esters (P-AAR-PEG), have been synthesized from natural diterpenic rosin. Their structures were characterized by Fourier Transform Infrared Spectrometer (FTIR) and their molecular weights were characterized by Gel Permeation Chromatography (GPC). Their critical micelle concentration (CMC), surface tension (γ CMC ), foaming property (FP), and hydrophile-lipophile balance (HLB) value were evaluated. Their thermal properties were measured by Thermal Gravimetric Analyzer (TGA) and fluid behaviors were studied by Rotational Rheometer. The influence of concentration on the properties of oil-in-water emulsions was examined and contrasted the stability of emulsion by the mean droplet size between day1 and day7. The weight-average molecular weight of P-AAR-PEG ranged from 1770 to 5071. CMC values of P-AAR-PEG were ranged from 0.33 to 0.87 g/L and the corresponding γ CMC values were ranged from 37.8 to 39.1 mN/m respectively. Their CMC and γ CMC values decreased and then increased with the increment of molecular weight of hydrophile group. Rheological measurements indicated that the P-AAR-PEG solutions changed from pseudoplastic property to Newtonian with increasing shear rate. P-AAR-PEG1000 had good emulsion ability to turpentine in water. When the concentration of P-AAR-PEG1000 was 8 wt%, the emulsion remained stable for more than 7 days.
研究领域:
高分子化学
·
表面与界面化学
·
材料科学
·
胶体化学
·
应用化学
✓ 已验证
DOI
高影响因子
CARBON
·
2013
·
IF 5.868
Xiuqing Meng,Sefaattin Tongay,Jun Kang,Zhanghui Chen,Fengmin Wu,Shu-Shen Li,Jian-Bai Xia,Jingbo Li,Junqiao Wu
ZnMg and NbCl 5 were intercalated in graphite and the presence of such molecules between the graphene sheets results in n- and p-type doping, respectively. The doping effect is confirmed by Hall and Raman measurements and the intercalation process is monitored by scanning tunneling microscopy . After intercalation the carrier concentration increase almost an order of magnitude and reaches values as high as 10 19 and 10 18 cm −3 for p- and n-type doping, respectively. For higher intercalation times, the intercalated graphite turns back to be as ordered as pristine one as evidenced by the reduction in the D peak in Raman measurements. Intercalation compounds show remarkable stability allowing us to permanently tune the physical properties of few-layer graphite. Our study has provided a new route to produce stable and functional graphite intercalation compounds and the results can be applied to other graphitic structures such as few-layer graphene on SiC.
研究领域:
凝聚态物理
·
材料科学
·
纳米科技
·
表面科学
·
半导体物理
✓ 已验证
DOI
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2022
·Vol. 24
·期 44
·27105-27113
·
IF 3.945
Panpan Peng,Chao Wang,Lanwei Li,Shuyao Li,Jing Chen,Pengya Fan,Rui Du,Haotian Si,Zhenxiang Cheng,Jianli Wang
Endotaxial nanostructures can reduce lattice thermal conductivity through enhancing phonon scattering without affecting electrical transport, leading to a high thermoelectric performance. On the other hand, band engineering can enhance electrical transport by improving the Seebeck coefficient through valence band convergence and the resonance level. In this paper, the synergistic effect of band engineering and endotaxial nanostructures was implemented in SnTe thermoelectric materials by alloying with AgCuTe and doping with Indium. The positron annihilation lifetime spectra show that the vacancy concentration in SnTe was reduced after alloying with AgCuTe, which led to a decreasing hole concentration and improved carrier mobility. Additionally, the diffusion of Ag in the matrix during the preparation can facilitate valence band convergence. Therefore, the power factor of SnTe is greatly increased to 18 μW cm−1 K−2 at 800 K, which can be further increased to 21.4 μW cm−1 K−2 at 800 K after In doping due to resonance level formation. Meanwhile, Cu2Te endotaxial nanostructures also can be observed in the TEM image after SnTe alloying with AgCuTe. So, the lattice thermal conductivity significantly reduced to 0.93 W m−1 K −1 in In-doped and AgCuTe-alloyed SnTe. Finally, we obtain an enhanced ZT value of 1.14 in Sn1.02In0.01Te–1%AgCuTe at 800 K.
研究领域:
材料科学
·
凝聚态物理
·
功能材料
·
热电转换
·
纳米结构调控
·
半导体物理
·
能源材料
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Bing Yang,Bo Wang,Peng Li,Jing Chen,Bo Li,Lushan Ma,Futian Zhang,Haitao Guo,Yunfeng Tian,Xuzhuo Sun,Bo Chi
In this study, we developed an innovative strategy to fabricate perovskite oxide powder with 12.356 m 2 /g of specific surface area. Polyacrylamide hydrogel was used as a template to prepare Sm 0.5 Sr 0.5 CoO 3-δ (SSC) powders with lamellar structure. The three-dimensional interconnected structured SSC electrodes with lamellar connections were fabricate using screen printing method. As a result, the oxygen vacancy concentration of the SSC powder obtained by the polyacrylamide template method was 0.625 and 0.642 at 650 °C and 700 °C respectively. At 650°C, the polarization resistance value was 0.11 Ω cm 2 for the novel SSC-PAM-V cathode. Compared with the SSC-SG cathode, the polarization resistance and activation energy of SSC-PAM-V were reduced by 50 % and 6.9 %, respectively. Furthermore, in a single cell with SSC-PAM-V electrodes, we achieved a maximum power density of 935 and 1243 mW cm −2 at 650 °C and 700 °C under wet H 2 conditions, demonstrating good electrochemical output performance. The layered porous electrode was not only suitable for the diffusion of oxygen, but also for increasing the reactive active sites. The proposed powder prepared with polyacrylamide hydrogel as template, was not only suitable for the optimization of perovskite oxide, but also for the application in other types of catalysis, providing the potential for improving the electro-catalytic activity of perovskite electrodes.
研究领域:
材料科学
·
电化学
·
能源材料
·
催化化学
·
固体离子学
✓ 已验证
DOI
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
·
2016
·
IF 2.196
Peizhu Zheng,Dongxing Cai,Jihua Zhao,Weiguo Shen
The mixed surfactants of dodecyltrimethylammonium bromide (DTAB) and 1-dodecyl-3-methylimidazolium bromide (C 12 mimBr) in aqueous solutions were studied by measurement of electrical conductivity and isothermal titration microcalorimetry (ITC). The critical micelle concentrations (cmc) and the degree of dissociations of counter ions were determined for this system at various surfactant compositions, and the thermodynamic properties of micellization were evaluated. A one-parameter Margules equation was used to fit the cmc values to calculate the mole fraction, the activity coefficients of two surfactant components and the excess properties in mixed micelles.
研究领域:
胶体化学
·
物理化学
·
表面化学
·
热力学
·
溶液化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）