The influence of Mo and ZrO_(2)nanoparticles addition on the interfacial properties and shear strength of Sn58Bi solder joint was investigated.The interfacial microstructures of Sn58Bi/Cu,Sn58Bi+Mo/Cu and Sn58Bi+ZrO_(...The influence of Mo and ZrO_(2)nanoparticles addition on the interfacial properties and shear strength of Sn58Bi solder joint was investigated.The interfacial microstructures of Sn58Bi/Cu,Sn58Bi+Mo/Cu and Sn58Bi+ZrO_(2)/Cu solder joints were analysed using a scanning electron microscope(SEM)coupled with energy dispersive X-ray(EDX)and the X-ray diffraction(XRD).Intermetallic compounds(IMCs)of MoSn_(2)are detected in the Sn58Bi+Mo/Cu solder joint,while SnZr,Zr_(5)Sn_(3),ZrCu and ZrSn_(2)are detected in Sn58Bi+ZrO_(2)/Cu solder joint.IMC layers for both composite solders comprise of Cu_(6)Sn_(5) and Cu_(3)Sn.The SEM images of these layers were used to measure the IMC layer’s thickness.The average IMC layer’s thickness is 1.4431μm for Sn58Bi+Mo/Cu and 0.9112μm for Sn58Bi+ZrO_(2)/Cu solder joints.Shear strength of the solder joints was investigated via the single shear lap test method.The average maximum load and shear stress of the Sn58Bi+Mo/Cu and Sn58Bi+ZrO_(2)/Cu solder joints are increased by 33%and 69%,respectively,as compared to those of the Sn58Bi/Cu solder joint.By comparing both composite solder joints,the latter prevails better as adding smaller sized ZrO_(2)nanoparticles improves the interfacial properties granting a stronger solder joint.展开更多
In recent decades, many additives with different characteristics have been applied to strengthen and toughen Al2O3-based ceramic cutting tool materials. Among them, SiC whiskers and SiC nanoparticles showed excellent ...In recent decades, many additives with different characteristics have been applied to strengthen and toughen Al2O3-based ceramic cutting tool materials. Among them, SiC whiskers and SiC nanoparticles showed excellent performance in improving the material properties. While no attempts have been made to add SiC whiskers and SiC nanoparticles together into the ceramic matrix and the synergistically toughening effects of them have not been studied. An Al2O3-SiCw-SiC np advanced ceramic cutting tool material is fabricated by adding both one-dimensional SiC whiskers and zero-dimensional SiC nanoparticles into the Al2O3 matrix with an effective dispersing and mixing process. The composites with 25 vol% SiC whiskers and 25 vol% SiC nanoparticles alone are also investegated for comparison purposes. Results show that the Al2O3-SiCw-SiCnp composite with both 20 vo1% SiC whiskers and 5 vol% SiC nanoparticles additives have much improved mechanical properties. The flexural strength of Al2O3-SiCw-SiCnp is 730＋ 95 MPa and fracture toughness is 5.6 ± 0.6 MPa.m1/2. The toughening and strengthening mechanisms of SiC whiskers and nanoparticles are studied when they are added either individually or in combination. It is indicated that when SiC whiskers and nanoparticles are added together, the grains are further refined and homogenized, so that the microstructure and fracture mode ratio is modified. The SiC nanoparticles are found helpful to enhance the toughening effects of the SiC whiskers. The proposed research helps to enrich the types of ceramic cutting tool and is benefit to expand the application range of ceramic cutting tool.展开更多
The Cu2O/SiC photocatalyst was obtained from SiC nanoparticles （NPs） modified by Cu2O. Their photocatalytic activities for reducing CO2 to CH3OH under visible light irradiation have been investigated. The results in...The Cu2O/SiC photocatalyst was obtained from SiC nanoparticles （NPs） modified by Cu2O. Their photocatalytic activities for reducing CO2 to CH3OH under visible light irradiation have been investigated. The results indicated that besides a small quantity of 6H-SiC, SiC NPs mainly consisted of 3C-SiC. The band gaps of SiC and Cu2O were estimated to be about 1.95 and 2.23 eV from UV-Vis spectra, respectively. The Cu2O modification can enhance the photocatalytic performance of SiC NPs, and the largest yields of methanol on SiC, Cu2O and Cu2O/SiC photocatalysts under visible light irradiation were 153, 104 and 191μmol/g, respectively.展开更多
Developing low-loading single-atom catalysts with superior catalytic activity and selectivity in formaldehyde(HCHO)oxidation at room temperature remains challenging.Herein,ZrO_(2)nanoparticles coupled low-loading Ir s...Developing low-loading single-atom catalysts with superior catalytic activity and selectivity in formaldehyde(HCHO)oxidation at room temperature remains challenging.Herein,ZrO_(2)nanoparticles coupled low-loading Ir single atoms in N-doped carbon(Ir_(1)-N-C/ZrO_(2))was prepared.The optimal Ir_(1)-N-C/ZrO_(2)with 0.25 wt%Ir loading delivers the high HCHO removal and conversion efficiency(>95%)at 20℃,which is higher than that over Ir_(1)-N-C with the same Ir loading.The specific rate can reach 1285.6 mmol gIr^(-1)h^(-1),surpassing the Ir based catalysts reported to date.Density functional theory calculation results and electron spin resonance spectra indicate that the introduction of Zr O_(2)nanoparticles modulate the electronic structure of the Ir single atoms,promoting O_(2)activation to·O_(2)^(–).Moreover,the Ir-C-Zr channel is favorable for the dissociation of·O_(2)^(–)to active oxygen atom(*O),and further accelerates the transformation of HCHO and intermediates(dioxymethylene and formates)to CO_(2)and H_(2)O.This work provides a facile strategy to design low-loading single-atom catalysts with high catalytic activity toward HCHO oxidation.展开更多
An efficient synthesis of hexahydropyrido[2,3-d]pyrimidinetrione derivatives is achieved via tandem Knoevenagel-Michael addition of aromatic aldehydes,methylcyanoacetate and 4（6）-aminouracil in solvent-free conditio...An efficient synthesis of hexahydropyrido[2,3-d]pyrimidinetrione derivatives is achieved via tandem Knoevenagel-Michael addition of aromatic aldehydes,methylcyanoacetate and 4（6）-aminouracil in solvent-free conditions in the presence of 10 mol%of ZrO_2 nanoparticles（ZrO_2 NPs） as a heterogenous catalyst.The procedure is formed in high yields,short reaction time and an environmentally friendly specificity.展开更多
Zirconia(ZrO_2)incorporated ceramic coatings were fabricated on biodegradable ZM21 Mg alloy by the PEO coupled with EPD process.Subsequently,the sample surface was modified by laser texturing to improve the corrosion ...Zirconia(ZrO_2)incorporated ceramic coatings were fabricated on biodegradable ZM21 Mg alloy by the PEO coupled with EPD process.Subsequently,the sample surface was modified by laser texturing to improve the corrosion resistance,roughness and cell proliferation and growth properties.The corrosion performance of the fabricated samples along with the substrate was studied by electrochemical measurements under simulated body fluid(SBF)environment.The cell direct contact assay was conducted for the substrate and fabricated samples using L-929 mouse fibroblast cells for 24 h.The phase contrast images of cell direct contact assay revealed that fabricated samples exhibited better contact and response with the fibroblast cells,compared to the substrate.The addition of nanoparticles in the PEO process,called PEO coupled EPD process,resulted in attaining a higher thickness and improved corrosion performance of the samples than the PEO coated samples.Among all the samples,laser surface textured PEO,and PEO-EPD coated samples unveiled enhanced corrosion resistance,cell growth,thereby enabling it as a suitable prototype for biodegradable implant applications.展开更多
With the trends of miniaturization and high density of electronic packaging,there has been an urgent demand to open up lead-free solders with high strength and ductility.In this study,a ZrO_(2)-reinforced Sn1.0Ag0.5Cu...With the trends of miniaturization and high density of electronic packaging,there has been an urgent demand to open up lead-free solders with high strength and ductility.In this study,a ZrO_(2)-reinforced Sn1.0Ag0.5Cu composite solder was designed.First,surface modification on ZrO_(2) was conducted with ball milling-pyrolysis method.Subsequently,NiO modified ZrO_(2)(NiO/ZrO_(2))was added to the solder matrix with ultrasonic stirring.The morphology and interface of NiO/ZrO_(2) were discussed.Moreover,the microstructure,interface and mechanical properties of the composite solders were systematically studied.The results showed that NiO nanoparticles were evenly adhered to the ZrO_(2) surface,and the interface relationship between them was semi-coherent and coherent.Further,an appropriate addition of NiO/ZrO_(2) could refine the microstructure of composite solders.The refinement mechanism was systematically investigated.Besides,a micro-mechanical lock and non-micropored clean interface was formed between NiO/ZrO_(2) and the solder matrix.The Sn/NiO/ZrO_(2) interface system based on mutual solid solution was ingeniously designed.The ultimate tensile strength and elongation were increased synergistically,and the fracture mechanism transformed from a ductile−brittle mixed fracture mode to a ductile fracture mode.Therefore,a lead-free solder with high strength and ductility was obtained.展开更多
Developing low toxicity and multifunctional theranostic nanoplatform is the key for precise cancer diagnosis and treatment.Herein,an inorganic-organic hybrid nanocomposite is designed by modifying zirconium dioxide(Zr...Developing low toxicity and multifunctional theranostic nanoplatform is the key for precise cancer diagnosis and treatment.Herein,an inorganic-organic hybrid nanocomposite is designed by modifying zirconium dioxide(ZrO_(2)) with polydopamine(PDA) followed by doping Mn^(2+) ions and functionalizing with Tween 20(Tween-ZrO_(2)@PDA-Mn2+) for multimodal imaging and chemo-photothermal combination therapy.The as-prepared nanocomposite exhibits good biocompatibility in vitro and in vivo.Specifically,it can be employed as a multifunctional platform not only for computed tomography(CT)imaging and T1-weighted magnetic resonance(MR) imaging,but also for efficient chemotherapeutic drug doxorubicin hydrochloride(DOX) loading.Importantly,because of the pronounced photothermal conversion performance and controllable DOX release ability triggered by the near-infrared(NIR)irradiation and acidic pH,the synergistic effect between photothermal the rapy and chemotherapy results in an enhanced cancer treatment efficacy in vivo.Our work provides a high-performance inorganicorganic hybrid nanotheranostic platform for chemo-photothermal cancer therapy guided by CT and MR imaging.展开更多
文摘The influence of Mo and ZrO_(2)nanoparticles addition on the interfacial properties and shear strength of Sn58Bi solder joint was investigated.The interfacial microstructures of Sn58Bi/Cu,Sn58Bi+Mo/Cu and Sn58Bi+ZrO_(2)/Cu solder joints were analysed using a scanning electron microscope(SEM)coupled with energy dispersive X-ray(EDX)and the X-ray diffraction(XRD).Intermetallic compounds(IMCs)of MoSn_(2)are detected in the Sn58Bi+Mo/Cu solder joint,while SnZr,Zr_(5)Sn_(3),ZrCu and ZrSn_(2)are detected in Sn58Bi+ZrO_(2)/Cu solder joint.IMC layers for both composite solders comprise of Cu_(6)Sn_(5) and Cu_(3)Sn.The SEM images of these layers were used to measure the IMC layer’s thickness.The average IMC layer’s thickness is 1.4431μm for Sn58Bi+Mo/Cu and 0.9112μm for Sn58Bi+ZrO_(2)/Cu solder joints.Shear strength of the solder joints was investigated via the single shear lap test method.The average maximum load and shear stress of the Sn58Bi+Mo/Cu and Sn58Bi+ZrO_(2)/Cu solder joints are increased by 33%and 69%,respectively,as compared to those of the Sn58Bi/Cu solder joint.By comparing both composite solder joints,the latter prevails better as adding smaller sized ZrO_(2)nanoparticles improves the interfacial properties granting a stronger solder joint.
基金Supported by National Natural Science Foundation of China(Grant No.51175305)
文摘In recent decades, many additives with different characteristics have been applied to strengthen and toughen Al2O3-based ceramic cutting tool materials. Among them, SiC whiskers and SiC nanoparticles showed excellent performance in improving the material properties. While no attempts have been made to add SiC whiskers and SiC nanoparticles together into the ceramic matrix and the synergistically toughening effects of them have not been studied. An Al2O3-SiCw-SiC np advanced ceramic cutting tool material is fabricated by adding both one-dimensional SiC whiskers and zero-dimensional SiC nanoparticles into the Al2O3 matrix with an effective dispersing and mixing process. The composites with 25 vol% SiC whiskers and 25 vol% SiC nanoparticles alone are also investegated for comparison purposes. Results show that the Al2O3-SiCw-SiCnp composite with both 20 vo1% SiC whiskers and 5 vol% SiC nanoparticles additives have much improved mechanical properties. The flexural strength of Al2O3-SiCw-SiCnp is 730＋ 95 MPa and fracture toughness is 5.6 ± 0.6 MPa.m1/2. The toughening and strengthening mechanisms of SiC whiskers and nanoparticles are studied when they are added either individually or in combination. It is indicated that when SiC whiskers and nanoparticles are added together, the grains are further refined and homogenized, so that the microstructure and fracture mode ratio is modified. The SiC nanoparticles are found helpful to enhance the toughening effects of the SiC whiskers. The proposed research helps to enrich the types of ceramic cutting tool and is benefit to expand the application range of ceramic cutting tool.
基金supported by the National Natural Science Foundation of China (Grant No. 20906034)the Key Academic Program of the 3rd Phase "211 Project" of South China Agricultural University (Grant No. 2009B010100001)China Postdoctoral Science Foundation (Grant No. 20080430820)
文摘The Cu2O/SiC photocatalyst was obtained from SiC nanoparticles （NPs） modified by Cu2O. Their photocatalytic activities for reducing CO2 to CH3OH under visible light irradiation have been investigated. The results indicated that besides a small quantity of 6H-SiC, SiC NPs mainly consisted of 3C-SiC. The band gaps of SiC and Cu2O were estimated to be about 1.95 and 2.23 eV from UV-Vis spectra, respectively. The Cu2O modification can enhance the photocatalytic performance of SiC NPs, and the largest yields of methanol on SiC, Cu2O and Cu2O/SiC photocatalysts under visible light irradiation were 153, 104 and 191μmol/g, respectively.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences,China(Nos.XDA23010300 and XDA23010000)National Science Foundation of China,China(Nos.52200137 and 21725102)+1 种基金the Plan for“National Youth Talents”GuangDong Basic and Applied Basic Research Foundation(No.2021A1515110427)。
文摘Developing low-loading single-atom catalysts with superior catalytic activity and selectivity in formaldehyde(HCHO)oxidation at room temperature remains challenging.Herein,ZrO_(2)nanoparticles coupled low-loading Ir single atoms in N-doped carbon(Ir_(1)-N-C/ZrO_(2))was prepared.The optimal Ir_(1)-N-C/ZrO_(2)with 0.25 wt%Ir loading delivers the high HCHO removal and conversion efficiency(>95%)at 20℃,which is higher than that over Ir_(1)-N-C with the same Ir loading.The specific rate can reach 1285.6 mmol gIr^(-1)h^(-1),surpassing the Ir based catalysts reported to date.Density functional theory calculation results and electron spin resonance spectra indicate that the introduction of Zr O_(2)nanoparticles modulate the electronic structure of the Ir single atoms,promoting O_(2)activation to·O_(2)^(–).Moreover,the Ir-C-Zr channel is favorable for the dissociation of·O_(2)^(–)to active oxygen atom(*O),and further accelerates the transformation of HCHO and intermediates(dioxymethylene and formates)to CO_(2)and H_(2)O.This work provides a facile strategy to design low-loading single-atom catalysts with high catalytic activity toward HCHO oxidation.
文摘An efficient synthesis of hexahydropyrido[2,3-d]pyrimidinetrione derivatives is achieved via tandem Knoevenagel-Michael addition of aromatic aldehydes,methylcyanoacetate and 4（6）-aminouracil in solvent-free conditions in the presence of 10 mol%of ZrO_2 nanoparticles（ZrO_2 NPs） as a heterogenous catalyst.The procedure is formed in high yields,short reaction time and an environmentally friendly specificity.
基金the grants received from the Science and Engineering Research Board(SERB),New Delhi(SR/S3/ME/0024/2011,dated 3rd July 2012)。
文摘Zirconia(ZrO_2)incorporated ceramic coatings were fabricated on biodegradable ZM21 Mg alloy by the PEO coupled with EPD process.Subsequently,the sample surface was modified by laser texturing to improve the corrosion resistance,roughness and cell proliferation and growth properties.The corrosion performance of the fabricated samples along with the substrate was studied by electrochemical measurements under simulated body fluid(SBF)environment.The cell direct contact assay was conducted for the substrate and fabricated samples using L-929 mouse fibroblast cells for 24 h.The phase contrast images of cell direct contact assay revealed that fabricated samples exhibited better contact and response with the fibroblast cells,compared to the substrate.The addition of nanoparticles in the PEO process,called PEO coupled EPD process,resulted in attaining a higher thickness and improved corrosion performance of the samples than the PEO coated samples.Among all the samples,laser surface textured PEO,and PEO-EPD coated samples unveiled enhanced corrosion resistance,cell growth,thereby enabling it as a suitable prototype for biodegradable implant applications.
基金supported by the China Scholarship Council(No.202008050209)。
文摘With the trends of miniaturization and high density of electronic packaging,there has been an urgent demand to open up lead-free solders with high strength and ductility.In this study,a ZrO_(2)-reinforced Sn1.0Ag0.5Cu composite solder was designed.First,surface modification on ZrO_(2) was conducted with ball milling-pyrolysis method.Subsequently,NiO modified ZrO_(2)(NiO/ZrO_(2))was added to the solder matrix with ultrasonic stirring.The morphology and interface of NiO/ZrO_(2) were discussed.Moreover,the microstructure,interface and mechanical properties of the composite solders were systematically studied.The results showed that NiO nanoparticles were evenly adhered to the ZrO_(2) surface,and the interface relationship between them was semi-coherent and coherent.Further,an appropriate addition of NiO/ZrO_(2) could refine the microstructure of composite solders.The refinement mechanism was systematically investigated.Besides,a micro-mechanical lock and non-micropored clean interface was formed between NiO/ZrO_(2) and the solder matrix.The Sn/NiO/ZrO_(2) interface system based on mutual solid solution was ingeniously designed.The ultimate tensile strength and elongation were increased synergistically,and the fracture mechanism transformed from a ductile−brittle mixed fracture mode to a ductile fracture mode.Therefore,a lead-free solder with high strength and ductility was obtained.
基金supported by the National Natural Science Foundation of China (Nos.51772293,U1932112,and 21471103)Beijing Natural Science Foundation (No.2202064)+1 种基金Science and Technology Innovation Service Ability Construction Project of the Beijing Municipal Commission of Education (No.19530050182)CAS Key Laboratory of Nano-Bio Interface (No.20NBI01)。
文摘Developing low toxicity and multifunctional theranostic nanoplatform is the key for precise cancer diagnosis and treatment.Herein,an inorganic-organic hybrid nanocomposite is designed by modifying zirconium dioxide(ZrO_(2)) with polydopamine(PDA) followed by doping Mn^(2+) ions and functionalizing with Tween 20(Tween-ZrO_(2)@PDA-Mn2+) for multimodal imaging and chemo-photothermal combination therapy.The as-prepared nanocomposite exhibits good biocompatibility in vitro and in vivo.Specifically,it can be employed as a multifunctional platform not only for computed tomography(CT)imaging and T1-weighted magnetic resonance(MR) imaging,but also for efficient chemotherapeutic drug doxorubicin hydrochloride(DOX) loading.Importantly,because of the pronounced photothermal conversion performance and controllable DOX release ability triggered by the near-infrared(NIR)irradiation and acidic pH,the synergistic effect between photothermal the rapy and chemotherapy results in an enhanced cancer treatment efficacy in vivo.Our work provides a high-performance inorganicorganic hybrid nanotheranostic platform for chemo-photothermal cancer therapy guided by CT and MR imaging.
