JOURNAL OF MATERIALS SCIENCE
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2018
·Vol. 53
·期 9
·6562-6573
·
IF 2.993
Jia Zhengfeng,Li Haoqi,Zhao Yao,Dikin Dmitriy A.,Ni Junjie,Zhao Limin,Zhen Jinming,Ge Bo,Shao Xin,Ren Fei
In this study, copper (Cu)/polydopamine (PDA) composite was fabricated by vacuum hot-press sintering of micrometer-sized Cu particles covered with PDA film tailored at the nanometer scale thickness. The resultant compacts exhibited much higher electrical conductivity than the uncoated counterparts. Analyses of sintered samples using scanning and transmission electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy revealed the conversion of PDA into carbonized PDA (cPDA). The increased mass density and grain growth are likely responsible for improved electrical conductivity of the composite material.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2018
·Vol. 29
·期 7
·5954-5960
·
IF 2.324
Wang Yan,Wang Yishu,Han Jing,Tan Shihai,Guo Fu
Sn grain orientation in solder matrix has recently been considered as one of the principal failure contributions in lead-free solder joints. Since β -Sn exhibits high anisotropy, the differences of electromigration behavior of solder joints with various grain orientations are dramatic. With different angle ( θ ) between the c -axis of Sn grain and the direction of electron flow, the solder joints often demonstrate varying degrees of electromigration-induced damage. The present investigation illustrated significant differences in microstructural features on the surface of Cu reinforced composite solder joints, even with similar angle θ . Two Cu particles reinforced Sn 3.5 Ag composite solder joints with the similar angle θ of 35° and 40° were selected to investigate the effects of Sn grain c -axis on electromigration under high current stressing for 528 h. A large number of Cu 6 Sn 5 compounds were observed and occupied nearly the whole surface with clear polarization effect in one sample. In contrast, very few Cu 6 Sn 5 were found on the surface of the solder matrix in the other sample after current stressing, and the Cu 6 Sn 5 which was formed after reflow disappeared with subsequent current stressing. Even though polarization effect was not obvious, and the cathode interfacial dissolution was observed on such sample. Systematic study revealed that the angle θ alone was not a sole factor to determine the electromigration damage. It has to be considered along with the coordinate system containing the orientation of the c -axis of the Sn grain, a more dominative factor for the diffusing species.
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GREEN CHEMISTRY
·
2018
·Vol. 20
·期 20
·4710-4718
·
IF 8.586
Mingming Zhou,Chaolin Li,Haijian Luo,Jingwen Wang,Xue Sun
A laboratory scale closed-loop cycle system for the complete regeneration of sodium persulfate/sulfuric acid etching solution (SPS) has been developed by anode oxidation of sulfate paired to cathode reduction of copper. A current-efficient (110%), zero-chemical dosage and zero-emission strategy for complete regeneration of SPS and recovery of copper was achieved. The micro-etching rate of the recycled SPS has no significant difference compared with that of the fresh SPS. On average, the cost of etching in this recycling system is decreased by 100%, compared with that in the current printed circuit boards used in industries. The full utilization of spent SPS realizes waste to wealth conversion in the true sense. The developed recycling system is a techno-economically feasible, environmentally friendly, sustainable, clean and green process for the reuse of SPS and recovery of valuable metal Cu through electrooxidation of sulfate paired to electroreduction of copper.
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ACS Applied Nano Materials
·
2018
·
IF 0
Zequn Yang,Hailong Li,Chen Liao,Jiexia Zhao,Shihao Feng,Pu Li,Xi Liu,Jianping Yang,Kaimin Shih
Rattle-type Fe3O4@CuS synthesized using a two-step method was applied for elemental mercury (Hg0) adsorption in coal combustion flue gas for the first time. The Fe3O4 with strong magnetization was an ideal candidate as a core to make the sorbent recyclable, while the stabilized ultrathin CuS shell assured that the Fe3O4@CuS had a higher Brunauer–Emmett–Teller (BET) surface area with more exposed active sites and stronger magnetization. The optimal operating temperature of 75 °C allowed for the injection of the sorbent between the wet desulfurization (WFGD) and wet electrostatic precipitator (WESP), which removed the detrimental influence of nitrogen oxides. Simulated flue gas (SFG) in this section showed a slight inhibitive effect on Hg0 adsorption over the Fe3O4@CuS, mainly due to the presence of water vapor (H2O). The inhibition of H2O was proven to be the result of an active site prevention effect instead of the widely recognized competitive adsorption effect. The adsorption capacity and rate of the Fe3O4@CuS for Hg0 capture reached 80.73 mg g–1 and 13.22 μg (g min)−1, which were the highest values among the magnetic sorbents currently reported for Hg0 removal from coal combustion flue gas. These properties allowed the sorbent to maintain a 100% Hg0 capture efficiency for more than 20 h with only a 50 mg dosage when no regeneration step was applied. Meanwhile, the contacting time between the sorbent and Hg0 was generally less than 5 s in a typical sorbent injection process. Polysulfides dominated the capturing process and primarily contributed to the extremely high adsorption capacity/rate. A multistep reaction mechanism was proposed to explain the Hg0 adsorption over Fe3O4@CuS. At the first stage, polysulfide participated in Hg0 adsorption as the most active component and was consumed rapidly. After that, S–S dimers, sulfides, and even copper-terminated sites functioned as the adsorption centers. The as-formed mercury–copper (Hg–Cu) amalgam was transformed into mercury sulfide (HgS), a process that was dependent on the extent of the saturation of sulfide sites. With these advantages, Fe3O4@CuS is a promising, cost-effective, highly recyclable, and efficient alternative to the traditional activated carbon for capturing Hg0 in coal combustion flue gases.
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ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
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2018
·
IF 3.974
Zhiyue Liao,Huabin Cao,Xueyan Dai,Chenghong Xing,Xiongwei Xu,Gaohui Nie,Caiying Zhang
To investigate the toxic effects of Molybdenum (Mo) and Cadmium (Cd) on trace elements in digestive organs of Shaoxing duck ( Anas platyrhyncha ), 120 Shaoxing ducks were randomly divided into control group and 5 treatment groups which were treated with a commercial diet containing different dosages of Mo and Cd. On the 60th and 120th days, the beak, esophagus, glandular stomach, muscular stomach, small intestine, large intestine and feces were collected to determine contents of Mo, Cd, copper (Cu), iron (Fe), zinc (Zn) and selenium (Se), then correlation analysis was performed. The results showed that Cd content in digestive organs significantly increased in co-treated groups compared to single treated groups and Mo concentration increased in Mo-treated groups compared to control group, whereas Cu, Fe, Zn and Se concentrations in digestive organs decreased in co-treated groups. Furthermore, Cd and Mo were mainly accumulated in the small intestine and esophagus, respectively. There was a strongly positive correlation between Cd and Mo while they had negative correlation with Cu, Fe, Zn and Se, respectively. In feces, Mo and Fe contents in high dose of Mo group and high Mo combined with Cd group were significantly higher than those in control group, and Cu content in all treated groups significantly increased and Cd, Zn and Se concentrations had no difference. The results indicated that dietary Mo or/and Cd might disturb homeostasis of trace elements in digestive organs of Shaoxing duck. Moreover, the two elements presented a synergistic relationship.
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ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY
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2018
·
IF 2.776
Min Xu,Huaqiao Tang,XueRong Zhou,Helin Chen,Qi Dong,Yuanli Zhang,Gang Ye,Fei Shi,Cheng Lv,Bo Jing,Changliang He,Ling Zhao,Yinglun Li
Copper nanoparticles (Cu NPs) have widespread application because of their special physicochemical characteristics, however we need to more clearly study the toxicity mechanism of Cu NPs to ensure its safe use in pharmaceutical and animal feed. Thus, the aim of this study was to evaluate the effects and mechanisms of sub-chronic exposure to Cu NPs on renal CYP450 s of rats. In this study, we investigated the effects of Cu NPs on renal oxidative stress, cytokines and histopathology of rats. We found that Cu NPs (200 mg/kg) significantly disordered the function and structure of the kidney and caused a dose-dependent increase in oxidative stress and cytokines, which significantly decreased the levels of mRNA, protein, and activity of CYP450 s. Micro-coppers (Cu MPs) and Cu ions have similar effects, but their effects on CYP450 s were weaker than Cu NPs. The expression of nuclear receptors were inhibited and the expression of Akt, STAT3/5, CREB, p70S6K, NF-κB, P38 and ERK1/2 were activated when the inhibition effects of CYP450 s activity were observed in renal of rats. Therefore, we believe that Cu NPs can activate the STAT, NF-κB and MAPK signaling pathways to down-regulate the expression and activity of CYP450 s by inducing oxidative stress and inflammatory response in rat kidney.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2018
·
IF 3.909
Cihui Tian,Sajid Asghar,Yurui Xu,Zhipeng Chen,Jingwei Zhang,Qineng Ping,Yanyu Xiao
Redox-sensitive micelles based onhydrophilic hyaluronic acid-ss-hydrophobic curcumin conjugate were designed as a novel delivery system for gliomas targeting. Furthermore, the obtained micelles were further functionalized with Tween 80 (CUR-THSC) for better brain penetration. Dynamic light scattering experiment and in vitro release study showed that the synthetic disulfide-linked conjugate possessed redox-sensitivity under high glutathione conditions. Spherical micelles with a mean particle size of 74.2 nm, negative zeta potential (−30.25 mV), high entrapment efficiency (94.12%) and drug loading (8.9%) were obtained. XRD analysis of micelles revealed amorphous form of the encapsulated drug. CUR-THSC micelles showed good plasma stability and did not induce any hemolysis in erythrocytes. In addition, highest cytotoxicity in G422 cells was observed compared to the free curcumin group and non-sensitive micelles group. These results indicate that the Tween 80-modified hyaluronic acid-ss-curcumin micelles could emerge as a promising platform for the delivery of curcumin in the treatment of gliomas.
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JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
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2018
·
IF 3.046
Xiaoshan Yang,Xiufang Cui,Guo Jin,Jinna Liu,Yanbo Chen,Zhe Liu
Laser additive manufacturing (LAM) is a novel method for processing compositionally graded alloys and becomes increasingly important in the context of next-generation manufacturing technology. In this work, (Fe 60 Co 35 Ni 5 ) 78 Si 6 B 12 Cu 1 Mo 3 soft magnetic alloys with different laser power were designed and processed by the LAM. The magnitudes of magnetic properties were analyzed, and the relationships among composition-microstructure-magnetic properties assessed. Results show that the (Fe 60 Co 35 Ni 5 ) 78 Si 6 B 12 Cu 1 Mo 3 alloys by LAM exhibits relative uniform microstructure and comparable magnetic property compared with those conventional processed alloys. The bcc dominated microstructures exhibit a substantially higher saturation magnetization (Ms). With the increase in power, the average grain size of the alloy increased slightly and the increasing volume fraction of the Fe Si phase leaded to the enhancement of magnetization. The (Fe 60 Co 35 Ni 5 ) 78 Si 6 B 12 Cu 1 Mo 3 alloys with laser power of 3000 W exhibits the highest Ms (199 emu/g). The appearance of Fe 3 B results in coarse dendrites and high coercivity (Hc) in the multiple re-heating cycles.
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MATERIALS AND CORROSION-WERKSTOFFE UND KORROSION
·
2019
·Vol. 70
·期 11
·1964-1976
·
IF 1.458
Jin Li,Daquan Zhang,Kai Zhang,Lixin Gao,Cheng Shi,Donghui Chen,Manhong Huang
The triazole inhibitor of 1-(p-tolylthio)-1H-1,2,3-triazole-4-carboxylic acid (TTC) was synthesized via the Cu(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition reaction. The self-assembling method was performed to fabricate the self-assembled film of TTC on the copper surface. The electrochemical measurement results indicate that the TTC film can efficiently protect the copper from corrosion in high concentrated industrial cooling water. The protection efficiency of TTC film for copper is 92.2%. Surface characterizations imply that the copper with TTC film after corrosion is covered with multiple protective layers. It probably contains Cu(I) and Cu(II) complexes mixed with nitrogenous compound, Cl − and SO 4 2− . The result of quantum chemical calculation shows that the superior performance of TTC film is related to the adsorption of TTC molecules on copper surface horizontally. This kind of adsorption is mainly achieved via the adsorption centers of triazole ring and O atoms in TTC molecule.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2018
·
IF 3.141
Xiaopeng Han,Ying Huang,Qiao Gao,Meng Yu,Xuefang Chen
Weak interfacial bonding and the agglomeration of reinforcements are critical challenges for the expected performance in thermal management materials, hindering the extensive application of aluminum matrix composites. In this work, Cu particles, nanotubes, Ag-coated graphite flakes and films, urea, and starch were mixed together to fabricate porous preforms, which then were infiltrated by vacuum gas pressure at 720 °C. The effects of graphite film thickness on the microstructure and properties of thermal conductivity (TC) and coefficient of thermal expension were investigated. The nanotube@Cu/Ag@graphite/aluminum composites exhibited a high TC of 451 W/mK and excellent bending strength of 74 MPa, which were approximately increased by 48.8% and 126%, respectively, as compared with the samples without graphite film.
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ADVANCED POWDER TECHNOLOGY
·
2018
·
IF 2.943
Kewei Li,Fei Gao
The heterogeneity of grain refinement and texture formation in conductive copper powder during pulsed electric current sintering have been investigated by means of microstructural analysis of the particle-contacting zone of the samples sintered with micron-sized powders. The particle-contacting region was indicated to experience a higher level of grain refinement than the particle center due to the inhomogeneous temperature distribution among the particle when pulsed electric current passed through. Meanwhile, two main textures of Cube (1 0 0)[0 0 1] texture and Goss (1 1 0)[0 0 1] texture were directly detected in the sintered Cu samples by a combination of electron backscatter diffraction and X-ray diffraction. Based on the experimental results, a feasible mechanism for the formation of texture during the pulsed electric current sintering has been proposed by considering the applied uniaxial pressure and pulsed electric current as well as the rearrangement of grains. In addition, the effects of heterogeneous grain refinement and texture formation on the tensile properties of the sintered Cu samples were also discussed based on the tensile properties and fractographic. These results would contribute to the basic understanding of the sintering mechanisms in pulsed electric current sintering process.
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CHEMOSPHERE
·
2019
·
IF 5.108
Huizhong Chi,Xu He,Jianqiao Zhang,Jun Ma
Degradation of naproxen, bisphenol S and ibuprofen in a hydroxylamine enhanced zero-valent copper (Cu 0 ) catalyzed peroxymonosulfate system was investigated for the first time. We found that hydroxylamine addition accelerated the reduction of Cu 2+ to Cu + as well as the corrosion of Cu 0 , and environmental friendly gas nitrogen was the main product of hydroxylamine. Additionally, hydroxyl radical and sulfate radical were identified to be the dominant reaction species by competitive experiments. The degradation of naproxen, bisphenol S and ibuprofen kept highly efficient in the pH range of 3.0–7.0 in Cu 0 /hydroxylamine/peroxymonosulfate process, with their degradation products identified by HPLC-MS, which showed that Cu 0 /hydroxylamine/peroxymonosulfate system could be an alternative to remove non-steroidal antiinflammatory drugs or plasticizers in wastewater. Furthermore, the effects of Cu 0 , hydroxylamine and peroxymonosulfate dosage were studied and optimized by a BBD based response surface model. This study provided a method to solve the disadvantages of Cu 0 /peroxymonosulfate systems, and gave a promising method to enhance the efficiencies of ZVMs activated system such as iron, cobalt and copper.
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