CERAMICS INTERNATIONAL
·
2020
·Vol. 46
·期 12
·20173-20182
·
IF 3.83
Shujie Gai,Haifeng Zhu,Peixin Gao,Cheng Zhou,Zihui Kong,Maxim S. Molokeev,Zhiyong Qi,Zhi Zhou,Mao Xia
Currently, phosphor-converted LEDs (pc-LEDs) are revolutionizing the industry of plant growth lighting. To meet the requirements of this technology, phosphors with tunable photoluminescence , high thermal stability and luminous intensity are required. Herein, we found that the simple substitution of yttrium for lanthanum in La 2 MgTiO 6 :Mn 4+ (LMT:Mn 4+ ) system could satisfy above three criteria simultaneously. The photoluminescence properties can be regulated by continuously controlling the chemical composition of La 2-x Y x MgTiO 6 :Mn 4+ solid solution . The La sites are occupied by Y ions , causing a significant blue shift in the emission spectra which owing to the change of local crystal field strengthen. Meanwhile, the thermal stability and decay lifetimes are also varied due to the variation of local structure and band gap energy. The thermal stability of the material reaches 83.5% at 150 °C, which is better than the reported La 2 MgTiO 6 :Mn 4+ and Y 2 MgTiO 6 :Mn 4+ phosphors. The electronic luminescence (EL) of pc-LED devices using La 2-x Y x MgTiO 6 :Mn 4+ red phosphor is evaluated, which matching the absorption regions of plant pigments well, reflecting the superiority of the studied phosphors in plant growth lighting areas.
研究领域:
材料科学
·
光电子学
·
无机化学
·
农业工程
·
固体物理
·
发光材料
·
植物生理学
✓ 已验证
DOI
高影响因子
Journal of Materiomics
·
2023
·Vol. 10
·期 5
·995-1003
·
IF 9.4
Wei Peng,Jianglei Chang,Jianwei Zhao,Dawei Wang,Zhen Liu,Genshui Wang,Shuxiang Dong
Piezoelectric PZT ceramics with high piezoelectric properties and good thermal stability are urgently desired concerning the practical application. New compositions of LiNbO 3 modified Pb(Ni 1/3 Nb 2/3 )O 3 PbZrO 3 PbTiO 3 ceramics have been prepared in this study. The effects of the introduction of the LiNbO 3 on the system were comprehensively investigated in terms of the phase structure, microstructure, electric properties, and thermal stability behavior of the ceramics. All compositions are located in the morphotropic phase boundary (MPB) region, and the ratio of the rhombohedral (R) phase increases obviously with the increase of LiNbO 3 concentration. With increasing the LiNbO 3 content, the piezoelectric properties were significantly enhanced. The sample added with 2% (in mole) LiNbO 3 shows excellent electric properties, including T m = 185 °C, ε r = 5,643, k p = 0.626, Q m = 51, d 33 = 902 pC/N. More importantly, no thermal depolarization behavior was observed in the temperature range of 25–100 °C. For PNN-PZT- x %LN ceramics, which is mainly attributed to the pinning effect resulted by the Li Pb ' − Nb Zr/Ti ∙ defect dipoles.
研究领域:
材料科学
·
功能陶瓷
·
压电材料
·
固态物理
·
电子材料
✓ 已验证
DOI
高影响因子
SURFACE & COATINGS TECHNOLOGY
·
2019
·
IF 3.192
Lu Zhu,Yousen Zhu,Xuanru Ren,Ping Zhang,Jianghao Qiao,Peizhong Feng
MoSi 2 -MoB-ZrO 2 composite powders are one-step synthesized prepared by self-propagating high-temperature synthesis (SHS), which are further utilized to prepare the oxidation protective coatings by spark plasma sintering (SPS) method on molybdenum substrate. Microstructure and properties of the coatings were investigated and determined. Oxidation behavior of the coatings at high temperature was also studied. The results showed that the composite coating is dense and crack-free due to the addition of ZrO 2 , which is beneficial for the decrease of mismatch in coefficient of thermal expansion, and no void exists in the diffusion layer owing to the diffusion of Si, which is inhibited by adding MoB. Compared with the pure MoSi2 coating, the high hardness of the composite coating is enhanced by about 20% while the fracture toughness of the composite coating is improved by about 25%, which makes the occurrence of intergranular fracture , crack deflection and crack bridging. After oxidation at 1400 °C for 80 h, MoSi 2 coating failed while xMoSi 2 -MoB-3ZrO 2 (x = 3, 4, 5) composite coating still kept its protective effect. Only a little substrate is consumed during oxidation and improved oxidation resistance is gained by MoSi 2 -MoB-ZrO 2 composite coating. 3MoSi 2 -MoB-3ZrO 2 coating shows the relatively best oxidation resistance due to the formation of crack-free oxide film on the surface of the coating.
研究领域:
材料科学
·
表面工程
·
高温氧化
·
陶瓷涂层
·
粉末冶金
✓ 已验证
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2023
·
IF 6
Bingyang Li,Meiqian Chen
Massive spent ion exchange resins (SIERs) containing radionuclides are produced in nuclear power plants , which need to be treated reasonably. The migration mechanism of nuclides in SIER in both pyrolysis and gasification was evaluated from the chemical equilibrium analysis based on the Gibbs free energy minimization. The maximum volatility degrees of Co, Sr and Cs at 400–600 °C and 0.1 MPa were 0.01%, 0% and 0.1% in the pyrolysis . The maximum volatility degrees of Co, Sr and Cs were 0.015%, 0% and 100% at 600–1300 °C and 0.1 MPa in the gasification, and the steam concentration should be set mainly how to limit the volatilization of radionuclides . To reduce the volatility of nuclides as much as possible, the temperatures should be kept below 600 °C and 870 °C in the pyrolysis and gasification, respectively. The volatilization of Cs was greatly inhibited with lifting the pressure from 0.1 MPa to 1.5 MPa, which decreased from 0.103% to 0.007% in the pyrolysis (600 °C) and from 4.80% to 0.30% in the gasification (715 °C), respectively. Based on preventing the nuclides leakage, the negative pressure in the gasification should be controlled between 0.097 and 0.099 MPa. The volatilization of radionuclides was effectively weakened by adding a fixative, Zr(HPO 4 ) 2 ·H 2 O, since it could be helpful to reduce the gaseous cesium-based products in the pyrolysis and gasification. The volatility degree of Cs was close to 0 if Zr/Cs was great than or equal to 0.5. This study could provide basic data for the pyrolysis and gasification treatment of SIER.
研究领域:
核化学
·
环境工程
·
放射化学
·
废物处理
·
热力学分析
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Zixiang Gao,Jun Liu,Ying Wang,Yuqiong Zhao,Guoqiang Li,Wenzhe Si,Yuefeng Liu,Guojie Zhang
Activated carbon (AC) adsorbents are extensively utilized for the adsorption and elimination of volatile organic compounds (VOCs), such as styrene, owing to their remarkable adsorption capacity and cost-effectiveness. However, the regeneration and reutilization of activated carbon face significant limitations due to incomplete cleavage of styrene and carbon accumulation during heated styrene cracking. This research focuses on the preparation of Ni-Fe bimetal-enriched adsorbent columns by successfully loading transition metals Ni and Fe onto activated carbon saturated with styrene adsorption using a simple impregnation method. A series of characterizations were conducted to unveil the formation process of active sites in the alloy phase and the mechanism behind the synergistic anti-accumulation effect of Ni and Fe on carbon deposits. Furthermore, the adsorption performance of the regenerated activated carbon for styrene was evaluated. The results revealed the formation of Fe 0.64 Ni 0.36 and Ni-Fe alloy (Kamacite) phases on the activated carbon carriers, which enhanced the cracking of styrene and exhibited superior anti-carbon accumulation properties. The styrene adsorption capacity of the synthesized bimetallic 2.5Fe-2.5Ni-900 regenerated sample reached 407.5 mg/g, approximately 1.5 times higher than that of the monometallic samples 5Fe-900 and 5Ni-900, and 1.6 times higher than that of the unmodified activated carbon RAC-900. Furthermore, kinetic studies indicated that the adsorption process of styrene by the samples followed a multilayer adsorption mechanism, predominantly governed by physical adsorption. Intra-pore diffusion was identified as the primary rate-determining step during the adsorption process. Moreover, after three regenerative adsorption cycles, the decrease in styrene adsorption capacity for the 2.5Fe-2.5Ni-900 sample was below 20 %. This study presents novel perspectives and methodologies for addressing the regeneration challenge of activated carbon saturated with styrene adsorption.
研究领域:
环境化学
·
吸附科学
·
材料再生
·
大气污染控制
·
环境功能材料
✓ 已验证
DOI
高影响因子
FUEL
·
2021
·
IF 6.609
Hongsheng Yu,Suhang Chen,Xiaodong Yu,Wei Zhang,Christian Paravan,Luigi T. DeLuca,Ruiqi Shen
The slow regression rate induced by the difficulty of pyrolysis has limited the practical application of hydroxyl-terminated polybutadiene (HTPB)-based fuels for hybrid rocket propulsion. A possible strategy is the use of suitable transition metal elements promoting polymer matrix thermal decomposition of fuels. This paper investigates the effects of nickel acetylacetonate, Ni(acac) 2 , on the thermal stability and combustion of HTPB-based fuel formulations. The presented experimental results show that the addition of Ni(acac) 2 can intensely decrease the thermal stability of HTPB thus enhancing the solid fuel regression rate even at a small additive mass fraction: under an oxygen mass flux of 50 kg/m 2 s, HTPB + 5 wt% Ni(acac) 2 shows a 25.5% increase over the non-loaded baseline. Kinetics analyses reveal that the catalytic effect is mainly induced by the Ni 2+ in Ni(acac) 2 at the early stage of decomposition, and by the NiO produced from the oxidative decomposition of Ni(acac) 2 in the fuel final degradation stage. On the other hand, the addition of Ni(acac) 2 decreases the combustion heat of HTPB-based fuels significantly and implies the accumulation of its decomposition products (much metal Ni, moderate elemental C, and a little NiO.) at the fuel regressing surface. Eventually, when the content of Ni(acac) 2 exceeds 5 wt%, the growth of regression rate slows down rapidly, and a performance detriment occurs at 40 wt%. This study verifies the catalytic effect of Ni(acac) 2 on polymer matrix for HTPB based fuels showing the attractive regression rate performance of this additive.
研究领域:
推进剂化学
·
燃烧学
·
高分子材料科学
·
航天动力工程
·
催化化学
✓ 已验证
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2024
·Vol. 12
·期 5
·114091
·
IF 7.4
Xiaolong Dai,Tiangui Qi,Xiaobin Li,Zhihong Peng,Guihua Liu,Qiusheng Zhou,Yilin Wang,Leiting Shen
In recent years, lithium iron phosphate (LFP) batteries have been widely used in the electric vehicle industry. The recycling of spent LFP will be propitious to conserving resources and alleviating the environmental risks it poses. In this study, a selective extraction method for lithium from spent LFP was proposed using nitric acid . Lithium leached into the liquid phase, while P and Fe remained in the leaching residue. Under the conditions of 120°C, HNO 3 /Li molar ratio of 2, and time of 2 h, the leaching efficiency of lithium reached 99.5 %, with a selectivity reaching 82.1 %. Initially, LFP was decomposed to liberate Li, Fe, and P in the liquid phase. Subsequently, ferrous ions were oxidized to trivalent, high-valent iron ions re-precipitated as FePO 4 ·2 H 2 O. Thermodynamic calculations indicate that the temperature and pH value of the extraction system have significant influence on both the oxidation and reprecipitation steps. An imbalance of Fe/P ratio (<1) in the raw material hinders the selectivity of lithium extraction , and supplementing this portion of Fe can enhance the selectivity to over 90 %. Additionally, LiCO 3 and anhydrous FePO 4 were effectively regenerated from the leachate and residue. This study provides a novel approach for the recycling of spent LFP and probably contributes to the sustainability of the lithium ion battery industry.
研究领域:
环境科学
·
冶金工程
·
材料回收
·
可持续能源
·
化学工程
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2019
·
IF 4.784
Junwang Zhang,Lili Song,Kunlan Li,Qingda An,Hao Ma,Liyu Yang,Ligang Wei
Water addition was found to enhance the thermal stability of alkylimidazolium–acetate ionic liquids (ILs). Especially in the case of high water content (30–50 wt%), few decomposition products can be observed in the 1 H NMR spectra even after treatment for 24 h at 150 °C. On the basis of this finding, lignin treatment of water and acetate IL mixtures (50–90 wt% IL content) were investigated at 150 °C. The addition of water, as opposed to pure IL treatment, can inhibit the lignin depolymerization into small fragments. Lignin degradation and the structure of regenerated lignin are more affected by cation types of ILs rather than the IL contents and pH values. In the case of 50–70 wt% 1-ethyl-3-methylimidazolium acetate–water system, the specific inter-unit linkages of lignin can be broken down, and regenerated lignin with a narrow polydispersity index (5.0–9.6) can be obtained.
研究领域:
绿色化学
·
生物质转化
·
高分子化学
·
离子液体化学
·
木质素化学
·
可持续材料
·
热化学转化
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Dan Wu,Mengnan Hu,Yongyi Zhang,Jing Zhou,Zhaona Wang
Surface enhanced Raman spectroscopy (SERS) is a key nondestructive detecting technology with a broad application demands. However, relative low stability and homogeneity of the SERS substrate hinder its practical applications. Here, a simple and flexible approach is proposed to achieve the arrayed SERS substrates with the periodicity and local randomness by directly growing silver nanoflowers on the patterned wafer fabricated by the optical interference method. By utilizing the hotspot effect of nanogaps within/between the Ag nanoflowers, the SERS substrates demonstrate the low detecting limit of 5 × 10 −10 M and 5 × 10 −9 M in one-dimensional (1D) and two-dimensional (2D) pattern structures for Rhodamine 6G (R6G) probe molecule, respectively. The periodicity assures the fabricated substrate a promising reproducibility and stability. After the 1D array structure is left for 21 days, the intensity of Raman signal of R6G maintains at 80%. Moreover, the proposed method has the advantages of simple preparation, low cost, flexible tunability, and easy-fabrication large scale substrate. The results indicate that the long-range ordered silver nanoflower array structures are promising candidates for the high performance SERS substrate in chemical analysis, medicine and environment monitoring.
研究领域:
分析化学
·
纳米生物技术
·
材料科学
·
环境监测
·
医学检测
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2017
·Vol. 135
·期 11
·45974
·
IF 1.86
Wenqi Xian,Lina Song,Baohua Liu,Hulan Ding,Zhao Li,Mengping Cheng,Le Ma
CO 2 copolymer diol-based thermal polyurethane elastomers (PPC-TPU) were prepared by the reaction of CO 2 copolymer diol and methylene diphenyl diisocyanate and chain extender (ethylene glycol/1,4-butanediol/1,6-hexanediol) (EG/BDO/HG). The rheological and mechanical properties of PPC-TPU were analyzed. The effects of shear rate, shear temperature, hard segment content, and variety of chain extender on the properties of PPC-TPU were studied. The results showed that the apparent viscosity (η) of PPC-TPU decreased with the increasing shear rate ( τ ), and the non-Newtonian index ( n ) was less than 1. PPC-TPU exhibited a typical character of pseudoplastic non-Newtonian rheological behavior. The degradation during the processing was obviously inhibited by adding plasticizer and antioxidant. It was also discovered that the apparent viscosity varied with the content of hard segment and chain extender. Under the same temperature (185 °C) and shear rate (50 s −1 ), the apparent viscosity increased considerably with the raise of hard segment content, and the apparent viscosity and tensile strength of PPC-TPU with EG as chain extender was the maximum. It can be seen that with the apparent shear rate increasing, the variation tendency of apparent shear stress levels off, and the nonlinear relationship of τ – γ curve tended to be obvious. PPC-TPU exhibited a typical character of pseudoplastic non-Newtonian rheological behavior. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 45974.
研究领域:
高分子材料科学
·
流变学
·
功能高分子
·
生物基聚合物
·
材料力学
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2022
·Vol. 139
·期 23
·52314
·
IF 3.057
Xiangrong Chen,Zelin Hong,Chao Dai,Muhammad Awais,Fan-Bo Meng,Ashish Paramane,Hao Li
This paper investigates the influence of voltage stabilizer and nanofiller addition on the insulation performance of the cross-linked polyethylene (XLPE). The test samples of XLPE/stabilizer blends consisting of 1 wt% m-aminobenzoic acid, XLPE nanocomposites consisting of 0.5 wt% nano MgO and XLPE hybrid composite consisting of both voltage stabilizer and nanofillers were prepared. Various physicochemical and electrical properties were measured to analyze the performance of prepared samples. The obtained results show that the addition of nanofillers deteriorates the electrical insulation performance of the XLPE. On the other hand, the voltage stabilizer addition proves to be suitable for enhancing the electrical insulation performance of the XLPE. Meanwhile, the hybrid XLPE composites have shown medium behavior. The voltage stabilizer addition reduces, but the nanofillers increase the space charge density inside the XLPE compared to pure XLPE. It is also found that the dispersion of the voltage stabilizer in the material is uniform, whereas the nanofillers are aggregated. Furthermore, both additives slightly improve the thermal stability of the XLPE. The trap level theory based on quantum chemical calculation is proposed to explain the influence mechanism of the additives on the XLPE.
研究领域:
高分子材料科学
·
电气工程
·
绝缘材料
·
介电物理
·
材料化学
·
聚合物纳米复合材料
✓ 已验证
DOI
高影响因子
CHEMICAL COMMUNICATIONS
·
2015
·Vol. 51
·期 48
·9785-9788
·
IF 6.834
Chao Wan,Dang-guo Cheng,Fengqiu Chen,Xiaoli Zhan
This communication describes the fabrication of Pt/CeO2 nanotube@SiO2 core–shell catalysts applied to highly efficient water–gas shift reaction, where the initial CO conversion is 30.2% at 250 °C. Pt/CeO2 nanotube@SiO2 core–shell catalysts show outstanding thermal stability, even after accelerated aging under reaction conditions at 450 °C for 6 h, and the morphology is also unchanged after thermal treatment at 800 °C.
研究领域:
材料科学
·
催化化学
·
纳米技术
·
能源化学
·
环境催化
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）