RARE METALS
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2020
·Vol. 40
·期 7
·1940-1948
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IF 2.161
Li Jia-Xin,Chen Yu-Hong,Bai Zhang-Jun,Zhao Bao-Jun,Jiang Liang,Wu Lan-Er
Ta–W alloys have unique properties but their applications at high temperatures are restricted due to their poor oxidation resistances. The addition of Al and Ti decreases the oxidation rate of the alloy, as Al-contained protective oxide layer could be formed. In this study, ternary and quaternary Ta–W alloys containing Al and Ti were prepared by hot press sintering. The microstructures and oxidation behaviors of the alloys were studied at 1173 K. The results show that the oxidation kinetics of all alloys follows a parabolic law at short oxidation periods. After cyclic oxidation, the kinetics of quaternary alloys still obeys the parabolic law but that of ternary alloy has been changed into linear law kinetics after 8-h oxidation. For ternary alloy, an outer layer with dense and continuous alumina was formed during the initial stage, and phase transformation caused the oxides to peel off. By comparison, the quaternary alloys depicted continuously solid solution of the oxides layer. Overall, Al and Ti played key roles in oxidation degree and affected the oxidation kinetics of ternary and quaternary alloys.
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Journal of Advanced Dielectrics
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2020
·
IF 0
Maomao Ju,Yawei Yang,Jianqiu Zhao,Xingtian Yin,Yutao Wu,Wenxiu Que
Interfacial water evaporation through solar heating with photothermal materials is a promising strategy for seawater desalination and wastewater purification. Tightly packed 2D membranes with high reflection losses and limited vapor escape channels result in a low evaporation rate. In this work, 3D MXene architecture was fabricated by dropping the delaminated Ti 3 C 2 ( d -Ti 3 C 2 ) nanosheets onto the carbonized melamine foam (CMF) framework. Owing to the macroporous 3D architecture, more effective broadband solar absorption and vapor escaping were achieved. As a result, the 3D CMF@ d -Ti 3 C 2 -based evaporator delivers a water evaporation rate of 1.60 kg/m 2 ⋅ h with a solar-to-vapor conversion efficiency of up to 84.6%.
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Nature Communications
·
2020
·Vol. 11
·期 1
·1-10
·
IF 12.121
Zhou Lu,Zhou Jun,Lai Wei,Yang Xudong,Meng Jie,Su Liangbi,Gu Chenjie,Jiang Tao,Pun Edwin Yue Bun,Shao Liyang,Petti Lucia,Sun Xiao Wei,Jia Zhenghong,Li Qunxiang,Han Jiaguang,Mormile Pasquale
In recent years, surface-enhanced Raman scattering (SERS) of a molecule/metal–semiconductor hybrid system has attracted considerable interest and regarded as the synergetic contribution of the electromagnetic and chemical enhancements from the incorporation of noble metal into semiconductor nanomaterials. However, the underlying mechanism is still to be revealed in detail. Herein, we report an irreversible accumulated SERS behavior induced by near-infrared (NIR) light irradiating on a 4-mercaptobenzoic acid linked with silver and silver-doped titanium dioxide (4MBA/Ag/Ag-doped TiO 2 ) hybrid system. With increasing irradiation time, the SERS intensity of 4MBA shows an irreversible exponential increase, and the Raman signal of the Ag/Ag-doped TiO 2 substrate displays an exponential decrease. A microscopic understanding of the time-dependent SERS behavior is derived based on the microanalysis of the Ag/Ag-doped TiO 2 nanostructure and the molecular dynamics, which is attributed to three factors: (1) higher crystallinity of Ag/Ag-doped TiO 2 substrate; (2) photo-induced charge transfer; (3) charge-induced molecular reorientation.
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PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2020
·
IF 10.652
Yapeng Tian,Chenhui Yang,Yi Tang,Yangyang Luo,Xiaojie Lou,Wenxiu Que
Supercapacitors with an advanced high volumetric energy density require a match of both electrodes materials and suitable electrolyte. Here, aqueous asymmetric supercapacitors are designed by employing layered Ti 3 C 2 T x as negative electrodes and highly compact activated carbon (AC) as positive electrodes. Ti 3 C 2 T x //AC asymmetric supercapacitors (Ti 3 C 2 T x //AC ASCs) with 1.7 V voltage window are designed by regulating the mass ratio of both electrodes, which results from the shift of the open circuit potential with different applied voltages. Then, dual-ion hybrid supercapacitors (Ti 3 C 2 T x //AC-KBr HSCs) are also constructed by introducing redox active (KBr) into traditional electrolyte (H 2 SO 4 ) for Ti 3 C 2 T x //AC ASCs to achieve a high volumetric energy density, in which fast hydronium ion intercalated pseudocapacitance happens at the Ti 3 C 2 T x negative electrode, while redox reaction of Br − /Br 3 − within the highly compact AC happens at the positive electrode. As a result, the Ti 3 C 2 T x //AC-KBr HSC achieves a high volumetric capacitance of 250 F cm −3 at 2 mV s −1 , a volumetric energy density of as high as 102.8 Wh L −1 at 424 W L −1 and an outstanding cycling stability with 122% capacitance retention after 6000 cycles. Furthermore, the self-discharge performance for the Ti 3 C 2 T x //AC-KBr HSC is obviously improved, which is mainly ascribed to the adsorption of oxidized species at the AC surface.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2020
·
IF 4.65
X.Q. Liu,C.J. Li,X. You,Z.Y. Xu,X. Li,R. Bao,J.M. Tao,J.H. Yi
Carbon nanotube reinforced aluminum matrix (CNT/Al) composites with various microstructures were fabricated by powder metallurgy via introducing nano-sized and micron-sized Ti powders into the CNT-Al system. The size-dependent effects of Ti powders on the microstructure evolution and mechanical properties were further investigated. The results reveal that the best enhancement (∼51% of UTS) was obtained by adding 80 nm sized Ti powders into the CNT/Al composite compared with the composite without Ti addition, which mainly derives from the synergistic strengthening of the homogenously dispersed CNTs, a large quantity of in-situ formed nano-sized TiAl 3 particles and fine grains. Meanwhile, it is also noted that the addition of micron-sized Ti powders can help the CNT dispersion in powder fabrication stage, and subsequently in-situ formed core-shell structured particles with different interface reaction degree in the Al matrix. Among them, 1 μm was determined to be the optimal size of Ti for the maximum formation of core-shell structured particles, which best exploits the load transfer ability of TiAl 3 shell layers at their interfaces, and finally attributes to significant strength enhancement (∼35% of UTS). This research provides a valuable reference concerning the size effects of addition metal in future fabrication of CNTs reinforced metal matrix composites with alternative microstructure.
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INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
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2020
·
IF 3.407
Longqing Chen,Wenbin Qiu,Hao Deng,Xiaoliang Yang,Yangyipeng Song,Jun Zhu,Jun Tang
The shrinkages presented in sintering process of tungsten alloys are extremely detrimental to their practical applications in fusion reactors. Positively in this work, we effectively reduced the shrinkages via synergistically applying Ti-doping and annealing process on tungsten‑potassium (WK) alloys. This shrinkage-fill effect only works in the one with trace amount of titanium doping, such as 0.05 wt%Ti or 0.5 wt%Ti. Due to such effect, the compressive strength was improved by ~18%. Based on morphological and elementary analyses, we speculated that the Ti-rich particles along the grain boundaries of WK alloys were activated and migrated into shrinkages during annealing. Further Ti doping (e.g. 1wt.%Ti) led to nanoscale grain refinement in WK alloys, which almost doubled the compressive strength. In this case, an unconventional grain-refinement model was proposed. Furthermore, anomalous grain growth was observed in WK-3wt.%Ti, which was attributed to the formation of Ti-rich regions and the corresponding raise of energy in grain boundaries. The fabricating strategies in this work may benefit the design of refractory tungsten alloys with less shrinkages and ultra-fine grains.
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JOURNAL OF POWER SOURCES
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2020
·
IF 8.247
Yangyang Luo,Chenhui Yang,Yapeng Tian,Yi Tang,Xingtian Yin,Wenxiu Que
To enhance rate and cycle performances of nickel sulfide, the two-dimensional (2D) titanium carbide (Ti 3 C 2 , MXene) with good electrical conductivity and electrochemical stability is chosen as 2D supporting matrix for synthesizing nickel sulfide/delaminated Ti 3 C 2 (Ni–S/d-Ti 3 C 2 ) nanohybrids by a solvothermal method . The Ni–S/d-Ti 3 C 2 nanohybrids show a coexistence of Ni 3 S 2 and NiS with the characteristic peak of d-Ti 3 C 2 nanosheets , and have electroactive species-on-sheet structures. The optimal Ni–S/1d-Ti 3 C 2 nanohybrid delivers a high specific capacity of 840.4 C g −1 at 1 A g −1 with enhanced capacity retention of 64.3% at 30 A g −1 and an outstanding cycle performance, which are ascribed to an integration of d-Ti 3 C 2 nanosheets that can act as electric channels to accelerate electrons transport at interface of the nanohybrid during charge-discharge processes. An increased Ni 2+ content and BET surface area also contribute to redox reactions of Ni–S/1d-Ti 3 C 2 nanohybrid electrode. An asymmetric supercapacitor (ASC) fabricated by using the Ni–S/1d-Ti 3 C 2 nanohybrid as positive electrode and d-Ti 3 C 2 film as negative electrode exhibits an energy density of 20.0 Wh kg −1 at 0.5 kW kg −1 and a good cycling stability. Our work provides a favorable ingenuity for synthesizing advanced nickel sulfide-based nanohybrids and an alternative strategy of using 2D MXene as capacitive electrode for high-performance supercapacitors .
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ANALYTICA CHIMICA ACTA
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2020
·
IF 5.977
Qi Kang,Qiao Zhang,Lixin Zang,Mengru Zhao,Xiaolan Chen,Dazhong Shen
Molecularly imprinting polymers (MIPs), as artificial antibodies with high recognition selectivity to template molecules, are widely used in various biosensors . To improve further the selectivity of MIPs-based photoelectrochemical (PEC) biosensors, we report a differential strategy using non-imprinted polymers (NIPs) as the reference. In a proof-to-concept example for the determination of dopamine (DA), MIPs and NIPs membranes were fabricated by electrochemical polymerization of polypyrrole membranes on the surface of graphene quantum dots (GQDs)/TiO 2 nanotubes (NTs). The photocurrent difference between the two PEC cells , MIPs@GQDs/TiO 2 NTs−Pt and NIPs@GQDs/TiO 2 NTs−Pt, was measured as the signal. As the non-specific adsorption of non-template molecules on the outside surface of MIPs and NIPs membranes is similar, the anti-interference ability for the determination of DA is much improved by using differential strategy. In the normal and differential PEC measurement models, 10.0 μM ascorbic acid is equivalent to 3.12 and 0.40 μM DA, respectively. Further, the smaller specific surface area in NIPs membrane was compensated by using a weight factor to correct the residual interference in a modified differential model. By using 10.0 μM ascorbic acid as the balance point, the presence of 10.0 μM H 2 O 2 , glutathione , uric acid or glucose is equivalent only to 0.090, 0.061,0.11 or 0.041 μM of DA, respectively, which are about 3–7% of their interference levels in the normal photocurrent model. The differential PEC method was applied in the determination of DA in serum samples in the linear range of 0.05–12.5 μM, with the detection limit of 0.018 μM.
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PubMed
高影响因子
Journal of Oceanology and Limnology
·
2020
·Vol. 38
·期 5
·1517-1531
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IF 0.617
Tian Jing,Chen Zhuoyuan,Jing Jiangping,Feng Chang,Sun Mengmeng,Li Weibing
The Cu 2 O/TiO 2 p-n heterojunction composite photoelectrodes were prepared by depositing Cu 2 O nanoparticles on the surface of TiO 2 nanotubes via anodic oxidation and constant current deposition. Field emission scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) analyses showed that Cu 2 O nanoparticles not only deposited on the surface of TiO 2 nanotube array, but also on the wall of TiO 2 nanotubes. The Cu 2 O deposition amount could be adjusted by changing the deposition time. The photoelectrochemical cathodic protection (PECCP) performance of the prepared photoelectrodes for 316L stainless steel (SS) was tested under visible light. The constant current deposition time had a significant effect on the PECCP performance of Cu 2 O/TiO 2 -X photoelectrodes and Cu 2 O/TiO 2 -20 had the best PECCP performance for the coupled 316L SS. This was attributed to the appropriate amount and thickness of Cu 2 O to form p-n heterojunctions with TiO 2 , in which separation of the photogenerated carriers was accelerated and transfer of the photogenerated electrons to 316L SS for PECCP was facilitated.
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SURFACE & COATINGS TECHNOLOGY
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2020
·
IF 3.784
Ying Zhang,Tengfei Han,Meng Xiao,Yifu Shen
(FeNiCoCrTi 0.5 )C x (x = 3 wt%, 6 wt%, 12 wt%) carbonized high-entropy alloy-based composite coatings , marked as C 3 , C 6 and C 12 , were prepared on 45 steel by laser cladding. The macroscopic morphology, phase, microstructure, hardness and wear resistance of coatings have been investigated systematically. The results indicate that diamond content has a significant influence on the microstructure and mechanical properties of (FeNiCoCrTi 0.5 )C x coating. (FeNiCoCrTi 0.5 )C x coatings, without pores and cracks, are well metallurgically bonded with substrate. The coatings consist of BCC solid solution, Cr 23 C 6 and TiC. The addition of diamond in (FeNiCoCrTi 0.5 )C x coating leads to the instability of BCC solid solution and facilitates the precipitation of carbides , which causes carbides to become coarse and aggregate into large blocks. The hardness of (FeNiCoCrTi 0.5 )C x coatings is much higher than that of the 45 steel, the average hardness of C 12 coating is 4 times the hardness of substrate. Besides, the hardness of (FeNiCoCrTi 0.5 )C x coating increases with the increase of diamond content. Nonetheless, compared to C 6 coating, the C 12 coating shows inferior tribological performance due to the brittleness . It is noteworthy that C 6 coating with outstanding wear resistance has the potential to apply in various fields of machinery industry, marine engineering and aerospace.
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INDUSTRIAL CROPS AND PRODUCTS
·
2020
·
IF 4.244
Min Shi,Yao Wang,Xiaorong Wang,Changping Deng,Wenzhi Cao,Qiang Hua,Guoyin Kai
Tanshinones and phenolic acids are two major groups of natural bioactive compounds in Salvia miltiorrhiza which exert excellent pharmacological activities. Due to low content in S.miltiorrhiza , it is urgent to enhance the production of the two compounds to meet the increasing need. The Arabidopsis basic helix-loop-helix (bHLH) transcription factor MYC2 was introduced into S. miltiorrhiza hairy roots. In the best transgenic line AtMYC2-3 , tanshinone yield was 14.06 mg/g dw which was increased by 5.45-fold more than that in the control line, while phenolic acid production was enhanced to 95.9 mg/g dw, a 3.3-fold increase compared with the control. Transcript levels of some genes involved in biosynthesis of tanshinones and phenolic acids were noticeably upregulated. Dual-luciferase assay revealed that AtMYC2 activated the expression of biosynthetic genes including SmDXS2 and SmTAT . These results revealed that AtMYC2 plays a positive role in accumulation of both tanshinones and phenolic acids which provides a promising strategy for engineering tanshinone and phenolic acid production in S. miltiorrhiza .
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JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
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2020
·
IF 3.442
Hui Yong,Xin Wei,Yanhao Wang,Shihai Guo,Zeming Yuan,Yan Qi,Dongliang Zhao,Yanghuan Zhang
To improve hydrogen storage property of Mg-based alloy, the Mg–Ce–Y–Ni + 10 wt % M (M = Zr, Ti, V) composites were prepared by the combination of alloying and ball-milling, and their microstructure, phase evolution, as well as hydrogen storage thermodynamic and kinetic properties, were investigated by XRD , PCT, and DSC methods. The result shows that the hydrogenated samples are composed of MgH 2 , Mg 2 NiH 4 and corresponding ZrH 2 , TiH 2 and VH 1.9 phases. In comparison, the |Δ H| value of M = Ti sample is larger than that of M = Zr and M = V samples, and the M = Ti sample has the highest the peak temperatures and lowest plateau pressure, which indicates that Zr and V elements are more efficient to reduce the thermodynamic stability of RE-Mg-Ni hydrogen storage alloys. Besides, the DSC curve of the M = V sample has another endothermic peak which corresponds to the decomposition reaction between VH 1.9 and VH 0.8 , which has a contribution to desorption kinetic property for the M = V sample. The apparent activation energies ( E de ) show an increasing trend in the following order: M = Zr (87.7 kJ/mol) < M = V (89.1 kJ/mol) < M = Ti (99.3 kJ/mol).
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危险品化学品经营许可证（带存储）