The preparation of lead-free thick-film resistors are reported:using RuO 2 and ruthenates as conductive particles,glass powders composed of B 2 O 3,SiO 2,CaO and Al2 O 3 as insulating phase,adding organic matter which...The preparation of lead-free thick-film resistors are reported:using RuO 2 and ruthenates as conductive particles,glass powders composed of B 2 O 3,SiO 2,CaO and Al2 O 3 as insulating phase,adding organic matter which mainly consists of ethyl cellulose and terpineol to form printable pastes.Resistors were fabricated and sintered by conventional screen-printing on 96%Al 2 O 3 substrates,and then sintering in a belt furnace.X-ray diffraction(XRD) and electron scanning microscopy(SEM) have been used to characterize the conductive particles.The resistors exhibit good refiring stability and low temperature coefficient of resistance.Sheet resistance spans from about 80Ω/□ to 600Ω/□.The resistors prepared are qualified for common use.展开更多
CuO-doped（Ag0.75Li0.1Na0.1K0.05）NbO3（ALNKN-xCuO, x = 0.2mol%） lead-free piezoelectric ceramics were prepared by the solid-state reaction method in air atmosphere. The effects of CuO addition on the phase structure...CuO-doped（Ag0.75Li0.1Na0.1K0.05）NbO3（ALNKN-xCuO, x = 0.2mol%） lead-free piezoelectric ceramics were prepared by the solid-state reaction method in air atmosphere. The effects of CuO addition on the phase structure, microstructure, and piezoelectric properties of the ceramics were investigated. The experimental results show that the ALNKN ceramics without doping CuO possess rhombohedral phase along with K2NbrO16- type phase and metallic silver phase. For all of the CuO-doped ALNKN ceramics, a pure perovskite structure with the orthorhombic phase was obtained by enclosing the samples in a corundum tube. A homogeneous microstructure with＇the grain size of about 1 ~tm was formed for the ceramics with 0.5mo1% CuO. The grain size increases with increasing amount of CuO. The temperature dependence of dielectric properties indicates that the ferroelectric phase of the ALNKN-xCuO ceramics becomes less stable with the addition of CuO. The ceramics with x = lm01% exhibit relatively good electrical properties along with a high Curie temperature. These results will provide a helpful guidance to preparing other AN-based ceramics by solid-state reaction method in air atmosphere.展开更多
For the purpose of alleviating the adverse effect of paste aging on the properties of corn starch film, a series of electroneutrally quaternized/sulfosuccinylated starches（EQSS） with different degrees of substitutio...For the purpose of alleviating the adverse effect of paste aging on the properties of corn starch film, a series of electroneutrally quaternized/sulfosuccinylated starches（EQSS） with different degrees of substitution（DS） were synthesized via the quaternization/sulfosuccination of acid-thinned corn starch（ATS） by varying the amounts of N-（3-chloro-2-hydroxypropl） trimethylammonium chloride, maleic anhydride, and sodium hydrogen sulfite. The influence of paste aging on the properties of starch film cast from heat-induced starch paste was investigated and the properties were explored in terms of tensile strength, elongation, work at break, degree of crystallinity, and flex-fatigue resistance. The experimental results showed that the paste ageing generated adverse influence on the elongation, work at break, and flex-fatigue resistance of starch film. Further experiments showed that electroneutral quaternization/sulfosuccination of starch were able to alleviate the negative effect of paste ageing on the elongation, work at break, and flex-fatigue resistance, thereby obviously enhancing the elongation, work at break and flex-fatigue resistance, and thus reducing the drawback of brittleness. The enhancement depended on the amounts of the substituents introduced. With the increase in DS value, the elongation and work at break as well as flex-fatigue resistance continuously rose, whereas the tensile strength gradually reduced.展开更多
The influence of superplasticizer（SP） on the early age drying shrinkage of cement paste with the same consistency was investigated. To conduct the test, which lasted for 72 hours, three paste mixtures were used for ...The influence of superplasticizer（SP） on the early age drying shrinkage of cement paste with the same consistency was investigated. To conduct the test, which lasted for 72 hours, three paste mixtures were used for comparison. The 72 hours early age drying shrinkage staring from the initial setting time was measured by a clock gauge. The pore size distribution was measured by Mercury Intrusion Method. The surface tension of capillary simulation liquid and mass loss of paste were also measured. The experimental results showed that the addition of SP increased the early drying shrinkage greatly. The ratios of water evaporation and the total free water in mixtures added with SPs showed great differences. SPs fined the capillary pores of paste, and the volume of pore with diameter within 50 nm was well consistent with shrinkage rate. The addition of SPs did not raise the capillary liquid surface tension. It showed that with the volume of pore with diameter within 50 nm and the ratio of water evaporation and the total free water a tolerable shrinkage result of paste added with SP could be predicted, and the elastic modulus could have an influence on the early shrinkage. These results have never been proposed before.展开更多
Objective:To provide a possible basis for the anti-aging effect of modified Qiongyu paste(MQP).Methods:Ultra-high-performance liquid chromatography-Q-Orbitrap mass spectrometry was applied to confirm the effective com...Objective:To provide a possible basis for the anti-aging effect of modified Qiongyu paste(MQP).Methods:Ultra-high-performance liquid chromatography-Q-Orbitrap mass spectrometry was applied to confirm the effective components of MQP that we had identified from databases and research literature.Then,network pharmacology was employed to predict the possible underlying mechanism of MQP against aging.According to the overlap with age-related gene targets,we obtained key targets of MQP against aging using protein-protein interaction analyses.Superoxide dismutase(SOD)tests were performed in vitro and in vivo.Western blotting of P62 and LC3B and quantitative polymerase chain reaction of the expression of the P62,LC3B,HO-1,Keap1,and Nrf2 genes were conducted on H_(2)O_(2) -induced PC12 cells.Enzyme-linked immunosorbent assays of tumor necrosis factor-a and interleukin-6 were conducted on a D-galactose-induced aging mice model.Results:A total of 44 compounds in MQP were finally identified,and 48 gene targets were considered related to anti-aging.Kyoto Encyclopedia of Genes and Genomes and Gene Ontology enrichment analyses linked the principal anti-aging mechanisms of MQP to oxidative resistance,genomic stabilization,and growth hormone regulation.In vitro,H_(2)O_(2)-induced PC12 cells showed that MQP was able to activate SOD,prolong telomeres,and enhance the expression levels of P62,LC3B,HO-1,Keap1,and Nrf2.The quantitative polymerase chain reaction results were affirmed with the reactive oxygen species inhibitor N-acetylcysteine and the reactive oxygen species agonist diallyl-tetrasulfide.In vivo,the D-gal-induced aging mice showed that MQP increased SOD in the brain and reduced tumor necrosis factor-α and interleukin-6 in the serum.Thus,our results suggest that the mechanism of the anti-aging effect of MQP primarily involves antagonizing oxidative stress.Conclusion:From the analyses and experimental validation,we may conclude that oxidative stress resistance may be a potential mechanism of the MQP anti-aging effect.展开更多
In this work, the wettability, aging and shear properties of a new type of lead-free solder paste Sn-01Ag-Q5Cu ＋ BiNi （SACBNQ7） was investigated by conducting a series of comparison experiments with SAC305 and SAC...In this work, the wettability, aging and shear properties of a new type of lead-free solder paste Sn-01Ag-Q5Cu ＋ BiNi （SACBNQ7） was investigated by conducting a series of comparison experiments with SAC305 and SAC0307 solder paste. The results show that wettability of SACBNQ1 is almost equal to SAC3Q5,and better than that of SACQ3Q1 solder paste. The thickness of intermetallic compound （IMC） layer in SACBNQl/Cu is lower than that o f other two types o f solder joint after aging. And Cu3Sn layer of SACBNQl/Cu is thinner than that of SAC3Q5 and SAC0307. In addition, the SACBNQ7 solder joints perform the best shear strength among these three types of solder pastes.展开更多
Composite solders were prepared by mechanically dispersing different volumes of nano-sized Ag particles into the Sn-0.7Cu eutectic solder. The effects of Ag particle addition on the microstructure of Sn-0.7Cu solder j...Composite solders were prepared by mechanically dispersing different volumes of nano-sized Ag particles into the Sn-0.7Cu eutectic solder. The effects of Ag particle addition on the microstructure of Sn-0.7Cu solder joints were investigated. Besides, the effects of isothermal aging on the microstructural evolution in the interfacial intermetallic compound （IMC） layer of the Sn-0.7Cu solder and the composite solder reinforced with 1vol% Ag particles were analyzed, respectively. Experimental results indicate that the growth rate of the interfacial IMC layer in the Ag particles reinforced composite solder joint is much lower than that in the Sn-0.7Cu solder joint during isothermal aging. The Ag particles reinforced composite solder joint exhibits much lower layer-growth coefficient for the growth of the IMC layer than the corresponding solder joint.展开更多
The electroplated(111)-oriented nanotwinned-Cu(nt-Cu) film was utilized as substrate for Ag and Cu sinter joining to improve the weak interface connection between the metal paste and the substrate.It was found that bo...The electroplated(111)-oriented nanotwinned-Cu(nt-Cu) film was utilized as substrate for Ag and Cu sinter joining to improve the weak interface connection between the metal paste and the substrate.It was found that both Cu and Ag sinter joints using(111)-oriented nt-Cu film exhibited a higher bonding strength than that using traditional random-oriented Cu film.Especially,the joints sintered with Cu paste on(111)-oriented nt-Cu film possessed a higher bonding strength of 53.7 MPa at the sintering condition of 300 °C,0.4 MPa in N2 atmosphere,compared to that on random-oriented Cu film with a value of 31.3 MPa.The results show that as metal substrate layer,the(111)-oriented nt-Cu film can improve the connection performance of Ag and Cu sinter joints,which could further promote their application in dieattachment technology for the next-generation power semiconductors.展开更多
文摘The preparation of lead-free thick-film resistors are reported:using RuO 2 and ruthenates as conductive particles,glass powders composed of B 2 O 3,SiO 2,CaO and Al2 O 3 as insulating phase,adding organic matter which mainly consists of ethyl cellulose and terpineol to form printable pastes.Resistors were fabricated and sintered by conventional screen-printing on 96%Al 2 O 3 substrates,and then sintering in a belt furnace.X-ray diffraction(XRD) and electron scanning microscopy(SEM) have been used to characterize the conductive particles.The resistors exhibit good refiring stability and low temperature coefficient of resistance.Sheet resistance spans from about 80Ω/□ to 600Ω/□.The resistors prepared are qualified for common use.
基金Funded by the Scientific Research Fund of Sichuan Provincial Education Department(No.11ZB109)
文摘CuO-doped（Ag0.75Li0.1Na0.1K0.05）NbO3（ALNKN-xCuO, x = 0.2mol%） lead-free piezoelectric ceramics were prepared by the solid-state reaction method in air atmosphere. The effects of CuO addition on the phase structure, microstructure, and piezoelectric properties of the ceramics were investigated. The experimental results show that the ALNKN ceramics without doping CuO possess rhombohedral phase along with K2NbrO16- type phase and metallic silver phase. For all of the CuO-doped ALNKN ceramics, a pure perovskite structure with the orthorhombic phase was obtained by enclosing the samples in a corundum tube. A homogeneous microstructure with＇the grain size of about 1 ~tm was formed for the ceramics with 0.5mo1% CuO. The grain size increases with increasing amount of CuO. The temperature dependence of dielectric properties indicates that the ferroelectric phase of the ALNKN-xCuO ceramics becomes less stable with the addition of CuO. The ceramics with x = lm01% exhibit relatively good electrical properties along with a high Curie temperature. These results will provide a helpful guidance to preparing other AN-based ceramics by solid-state reaction method in air atmosphere.
基金Funded by the Open Project Program of Key Laboratory of Eco-Textiles,Ministry of Education,China(No.KLET0617)the Scientific Research Fund of Talent Introduction of Anhui Polytechnic University(No.2016YQQ004)
文摘For the purpose of alleviating the adverse effect of paste aging on the properties of corn starch film, a series of electroneutrally quaternized/sulfosuccinylated starches（EQSS） with different degrees of substitution（DS） were synthesized via the quaternization/sulfosuccination of acid-thinned corn starch（ATS） by varying the amounts of N-（3-chloro-2-hydroxypropl） trimethylammonium chloride, maleic anhydride, and sodium hydrogen sulfite. The influence of paste aging on the properties of starch film cast from heat-induced starch paste was investigated and the properties were explored in terms of tensile strength, elongation, work at break, degree of crystallinity, and flex-fatigue resistance. The experimental results showed that the paste ageing generated adverse influence on the elongation, work at break, and flex-fatigue resistance of starch film. Further experiments showed that electroneutral quaternization/sulfosuccination of starch were able to alleviate the negative effect of paste ageing on the elongation, work at break, and flex-fatigue resistance, thereby obviously enhancing the elongation, work at break and flex-fatigue resistance, and thus reducing the drawback of brittleness. The enhancement depended on the amounts of the substituents introduced. With the increase in DS value, the elongation and work at break as well as flex-fatigue resistance continuously rose, whereas the tensile strength gradually reduced.
文摘The influence of superplasticizer（SP） on the early age drying shrinkage of cement paste with the same consistency was investigated. To conduct the test, which lasted for 72 hours, three paste mixtures were used for comparison. The 72 hours early age drying shrinkage staring from the initial setting time was measured by a clock gauge. The pore size distribution was measured by Mercury Intrusion Method. The surface tension of capillary simulation liquid and mass loss of paste were also measured. The experimental results showed that the addition of SP increased the early drying shrinkage greatly. The ratios of water evaporation and the total free water in mixtures added with SPs showed great differences. SPs fined the capillary pores of paste, and the volume of pore with diameter within 50 nm was well consistent with shrinkage rate. The addition of SPs did not raise the capillary liquid surface tension. It showed that with the volume of pore with diameter within 50 nm and the ratio of water evaporation and the total free water a tolerable shrinkage result of paste added with SP could be predicted, and the elastic modulus could have an influence on the early shrinkage. These results have never been proposed before.
基金This study was supported by the National Key Research and Development Program of China(2019YFC1710105).
文摘Objective:To provide a possible basis for the anti-aging effect of modified Qiongyu paste(MQP).Methods:Ultra-high-performance liquid chromatography-Q-Orbitrap mass spectrometry was applied to confirm the effective components of MQP that we had identified from databases and research literature.Then,network pharmacology was employed to predict the possible underlying mechanism of MQP against aging.According to the overlap with age-related gene targets,we obtained key targets of MQP against aging using protein-protein interaction analyses.Superoxide dismutase(SOD)tests were performed in vitro and in vivo.Western blotting of P62 and LC3B and quantitative polymerase chain reaction of the expression of the P62,LC3B,HO-1,Keap1,and Nrf2 genes were conducted on H_(2)O_(2) -induced PC12 cells.Enzyme-linked immunosorbent assays of tumor necrosis factor-a and interleukin-6 were conducted on a D-galactose-induced aging mice model.Results:A total of 44 compounds in MQP were finally identified,and 48 gene targets were considered related to anti-aging.Kyoto Encyclopedia of Genes and Genomes and Gene Ontology enrichment analyses linked the principal anti-aging mechanisms of MQP to oxidative resistance,genomic stabilization,and growth hormone regulation.In vitro,H_(2)O_(2)-induced PC12 cells showed that MQP was able to activate SOD,prolong telomeres,and enhance the expression levels of P62,LC3B,HO-1,Keap1,and Nrf2.The quantitative polymerase chain reaction results were affirmed with the reactive oxygen species inhibitor N-acetylcysteine and the reactive oxygen species agonist diallyl-tetrasulfide.In vivo,the D-gal-induced aging mice showed that MQP increased SOD in the brain and reduced tumor necrosis factor-α and interleukin-6 in the serum.Thus,our results suggest that the mechanism of the anti-aging effect of MQP primarily involves antagonizing oxidative stress.Conclusion:From the analyses and experimental validation,we may conclude that oxidative stress resistance may be a potential mechanism of the MQP anti-aging effect.
基金supported by National Natural Science Foundation of China(Grant No.51174069)
文摘In this work, the wettability, aging and shear properties of a new type of lead-free solder paste Sn-01Ag-Q5Cu ＋ BiNi （SACBNQ7） was investigated by conducting a series of comparison experiments with SAC305 and SAC0307 solder paste. The results show that wettability of SACBNQ1 is almost equal to SAC3Q5,and better than that of SACQ3Q1 solder paste. The thickness of intermetallic compound （IMC） layer in SACBNQl/Cu is lower than that o f other two types o f solder joint after aging. And Cu3Sn layer of SACBNQl/Cu is thinner than that of SAC3Q5 and SAC0307. In addition, the SACBNQ7 solder joints perform the best shear strength among these three types of solder pastes.
基金supported by the New Star Project of Beijing Science and Technology Commission, China (No.2004B03)
文摘Composite solders were prepared by mechanically dispersing different volumes of nano-sized Ag particles into the Sn-0.7Cu eutectic solder. The effects of Ag particle addition on the microstructure of Sn-0.7Cu solder joints were investigated. Besides, the effects of isothermal aging on the microstructural evolution in the interfacial intermetallic compound （IMC） layer of the Sn-0.7Cu solder and the composite solder reinforced with 1vol% Ag particles were analyzed, respectively. Experimental results indicate that the growth rate of the interfacial IMC layer in the Ag particles reinforced composite solder joint is much lower than that in the Sn-0.7Cu solder joint during isothermal aging. The Ag particles reinforced composite solder joint exhibits much lower layer-growth coefficient for the growth of the IMC layer than the corresponding solder joint.
文摘The electroplated(111)-oriented nanotwinned-Cu(nt-Cu) film was utilized as substrate for Ag and Cu sinter joining to improve the weak interface connection between the metal paste and the substrate.It was found that both Cu and Ag sinter joints using(111)-oriented nt-Cu film exhibited a higher bonding strength than that using traditional random-oriented Cu film.Especially,the joints sintered with Cu paste on(111)-oriented nt-Cu film possessed a higher bonding strength of 53.7 MPa at the sintering condition of 300 °C,0.4 MPa in N2 atmosphere,compared to that on random-oriented Cu film with a value of 31.3 MPa.The results show that as metal substrate layer,the(111)-oriented nt-Cu film can improve the connection performance of Ag and Cu sinter joints,which could further promote their application in dieattachment technology for the next-generation power semiconductors.
