Surface-enhanced Raman Spectroscopy(SERS)is a nondestructive technique for rapid detection of analytes even at the single-molecule level.However,highly sensitive and reliable SERS substrates are mostly fabricated with...Surface-enhanced Raman Spectroscopy(SERS)is a nondestructive technique for rapid detection of analytes even at the single-molecule level.However,highly sensitive and reliable SERS substrates are mostly fabricated with complex nanofabrication techniques,greatly restricting their practical applications.A convenient electrochemical method for transforming the surface of commercial gold wires/foils into silver-alloyed nanostructures is demonstrated in this report.Au substrates are treated with repetitive anodic and cathodic bias in an electrolyte of thiourea,in a one-pot one-step manner.X-rays absorption fine structure(XAFS)spectroscopy confirms that the AuAg alloy is induced at the surface.The unique AuAg alloyed surface nanostructures are particularly advantageous when served as SERS substrates,enabling a remarkably sensitive detection of Rhodamine B(a detection limit of 10^(-14)M,and uniform strong response throughout the substrates at 10^(-12)M).展开更多
For designing low-impedance magnetic tunnel junctions(MTJs),it has been found that tunneling magnetoresistance strongly correlates with the insulating barrier thickness,imposing a fundamental problem about the relatio...For designing low-impedance magnetic tunnel junctions(MTJs),it has been found that tunneling magnetoresistance strongly correlates with the insulating barrier thickness,imposing a fundamental problem about the relationship between spin polarization of ferromagnet and the insulating barrier thickness in MTJs.Here,we investigate the influence of alumina barrier thickness on tunneling spin polarization(TSP)through a combination of theoretical calculations and experimental verification.Our simulating results reveal a significant impact of barrier thickness on TSP,exhibiting an oscillating decay of TSP with the barrier layer thinning.Experimental verification is realized on FeNi/AlO_(x)/Al superconducting tunnel junctions to directly probe the spin polarization of FeNi ferromagnet using Zeeman-split tunneling spectroscopy technique.These findings provide valuable insights for designs of high-performance spintronic devices,particularly in applications such as magnetic random access memories,where precise control over the insulating barrier layer is crucial.展开更多
The liquid phase catalytic exchange(LPCE) reaction is an effective process for heavy water detritiation and production of deuterium-depleted potable water. In the current study, hydrophobic carbon-supported platinum c...The liquid phase catalytic exchange(LPCE) reaction is an effective process for heavy water detritiation and production of deuterium-depleted potable water. In the current study, hydrophobic carbon-supported platinum catalysts(Pt/C/PTFE) with high efficiency as reported previously for LPCE were prepared and comprehensive performance evaluation method is applied to evaluate the separation behaviors of LPCE systematically. Experimental results indicate that the optimum reaction temperature of 60–80℃ and the molar feed ratio G/L of 1.5–2.5 would lead to higher separation efficiencies. As to the packing method, a random packing mode with a packing ratio of hydrophobic catalysts 0.25 is recommended. In addition, thermodynamic analysis corresponds well with experimental results under lower temperature and G/L, while the suppression of kinetic factors should not be neglected when T > 80℃ and G/L > 1.5.展开更多
Bimetallic transition metal phosphides(TMPs)as potential candidates for superior electrochemical performance are still facing great challenges in the controllable preparation of two-dimensional(2 D)structures with hig...Bimetallic transition metal phosphides(TMPs)as potential candidates for superior electrochemical performance are still facing great challenges in the controllable preparation of two-dimensional(2 D)structures with high aspect ratio.Herein,a novel structure of quasi-monolayered NiCo-bimetal-phosphide(NiCoP)has been designed and successfully synthesized by the newly developed process combined with ultrasonic-cavitation and phase-transition.This is the first time to break through the controllable preparation of 2 D bimetal-phosphides with a thickness of 0.98 nm in sub-nanoscale.Based on the advantages of 2 D quasi-monolayer structure with dense crystalline-amorphous interface and the reconfigured electronic structure between Ni^(δ+)/Co^(δ+)and P^(δ-),the optimized Ni_(5%)CoP exhibits an outstanding bifunctional performance for electrocatalyzing both hydrogen evolution reaction and oxygen evolution reaction in an alkaline medium.Ni_(5%)CoP presents lower overpotentials and voltage of 84 mV&259 mV and1.48 V at the current density of 10 mA cm^(-2)for HER&DER and overall water splitting,respectively,which are superior to most other reported 2 D bimetal-phosphides.This work provides a new strategy to optimize the performance of electrolytic water for bimetal-phosphates and it may be of significant value in extending the design of other ultrathin 2 D structured catalysts.展开更多
Based on the nondestructive test data of operating railway tunnels in China, this paper summarizes the basic characteristics of the complex contact behavior between the rock mass and lining structure. The contact mode...Based on the nondestructive test data of operating railway tunnels in China, this paper summarizes the basic characteristics of the complex contact behavior between the rock mass and lining structure. The contact modes are classified into dense contact, local non-contact, and loose contact. Subsequently, the corresponding mechanical model for each contact mode is developed according to its mechanical characteristics using the complex variable method. In the proposed mechanical model, a special algorithm is introduced to detect whether the local non-contact zone is re-contacted. Besides, a novel conformal mapping method is also proposed to accurately calculate the mechanical response of the concrete lining. Finally, the accuracy of the proposed method is verified by comparing it with the finite element method(FEM). Several parameter investigations are conducted to analyze the effects of different contact modes on the rock-lining interaction. The results show that:(i) the height of the local noncontact area does not have a significant effect on the contact stress distribution if no re-contact occurs;(ii) backfill grouting can reduce the local stress concentration caused by poor contact modes;and(iii) reducing the friction coefficient of the interface can lead to a more uniform distribution of internal forces in the concrete lining.展开更多
Trifunctional Cu-mesh/Cu_(2)O@FeO nanoarrays heterostructure is designed and fabricated by integrating CuCu_(2)O@FeO nanoarrays onto Cu-mesh(CM)via an in situ growth and phase transformation process.It is successfully...Trifunctional Cu-mesh/Cu_(2)O@FeO nanoarrays heterostructure is designed and fabricated by integrating CuCu_(2)O@FeO nanoarrays onto Cu-mesh(CM)via an in situ growth and phase transformation process.It is successfully applied to efficiently mitigate the antibiotic pollution,including degradation of antibiotics,inactivation of antibiotic-resistant bacteria(ARB),and damage of antibiotics resistance genes(ARGs).Under visible-light irradiation,CM/CuCu_(2)O@FeO nanoarrays exhibit a superior degradation efficiency on antibiotics(e.g.,up to 99%in 25 min for tetracycline hydrochloride,TC),due to the generated reactive oxygen species(ROS),especially the dominant·O^(2−).It can fully inactivate E.coli(HB101)with initial number of~108 CFU mL^(−1) in 10 min,which is mainly attributed to the synergistic effects of 1D nanostructure,dissolved metal ions,and generated ROS.Meanwhile,it is able to damage ARGs after 180 min of photodegradation,including tetA(vs TC)of 3.3 log 10,aphA(vs kanamycin sulfate,KAN)of 3.4 log 10,and tnpA(vs ampicillin,AMP)of 4.4 log 10,respectively.This work explores a green way for treating antibiotic pollution under visible light.展开更多
[Objectives] This study was conducted to understand the current status of duck related research. [Methods] CiteSpace knowledge graph analysis tool, VOSviewer visual analysis software and HistCite citation graph analys...[Objectives] This study was conducted to understand the current status of duck related research. [Methods] CiteSpace knowledge graph analysis tool, VOSviewer visual analysis software and HistCite citation graph analysis tool were used to analyze the number of publications and subject distribution of duck-related research fields in the Web of Science core collection database. The main countries(regions) and institutions, the main academic journals, the main research scholars, the main research hotspots and their changing trends were used for quantitative analysis. [Results](1) Duck-related research is receiving more and more attention, which further supports ducks’ important significance in the livestock and poultry industry.(2) Countries such as China, the United States, Canada, and France had published more articles in this field, and there was close cooperation between countries.(3) The top two journals with local citations in the duck-related research fields were PLOS ONE and JOURNAL OF VIROLOGY, and the journal with the highest impact factor in 2019 was JOURNAL OF VIROLOGY.(4) High-yield scholars in duck related research fields included Cheng Anchun, Wang Mingshu, Jia Renyong, etc.(5) Infection was a research hotspot in duck-related research. Typical pathogenic microorganisms included Newcastle disease, Avian influenza, and campylobacter.(6) The future trend of duck-related research mainly focuses on breeds, living environment, diseases, and molecular mechanisms. [Conclusions] Based on data from the Web of Science core collection database, this paper provides a complete bibliometric analysis of the current research status of ducks.展开更多
Background: The aim of this study was to investigate the distribution of the c-erbB2 antisense probe labeled with superparamagnetic iron oxide nanoparticles in the major organs of mice by MR imaging. Methods: Sixty BA...Background: The aim of this study was to investigate the distribution of the c-erbB2 antisense probe labeled with superparamagnetic iron oxide nanoparticles in the major organs of mice by MR imaging. Methods: Sixty BALB/c mice were randomly divided into experimental and control groups. MR scans were performed in each mouse of the experimental group at five different time points (10, 30, 60, 180 and 360 min) after injection of the antisense probe. The signal from each major organ (liver, spleen, heart, kidney and muscle tissue) in comparison with the background signal (signal to noise ratio) was determined at each time point as a measure of the distribution of the antisense probe. Six control mice were killed at each of the same time points and the organs immediately removed for determination of their iron content. Results: After injection of the antisense probe, the highest enrichment of the probe was seen in the spleen, reaching a peak at 180 min, followed by the liver, muscle, heart and kidney. Conclusions: MR imaging can visualize the distribution of c-erbB2 antisense probe labeled with superparamagnetic iron oxide nanoparticles in the major organs of mice, and this may provide the basis for further in vivo studies of MR imaging time and dose selection.展开更多
The system controlled in synchronous frame is commonly used. However, it is a problem how to transform the controller in synchronous frame to stationary frame. This paper deduces the stationary frame equivalent model ...The system controlled in synchronous frame is commonly used. However, it is a problem how to transform the controller in synchronous frame to stationary frame. This paper deduces the stationary frame equivalent model of arbitrarily controller in synchronous frame. The equivalent model can reflect the control performance of the input signal at different frequency accurately. The unified frequency-domain model of the overall system can be established using the equivalent model, and the guidance for frequency analysis and stability analysis can be provided. Theoretical derivation and simulation results verify the correctness and generality of the equivalent model.展开更多
Nanolaminates are composed of nanoscale-thick alternating layers of different materials and their properties are dependent on the individual layers,the layer thickness and the interfaces between the layers.Nanolaminat...Nanolaminates are composed of nanoscale-thick alternating layers of different materials and their properties are dependent on the individual layers,the layer thickness and the interfaces between the layers.Nanolaminates composed of cubic crystal structured metals are usually ductile compared to nanolaminates containing hexagonal crystal structured metals.Mechanical properties such as strength and hardness of nanolaminates increase with a decrease in individual layer thickness down to a few nanometers and they become independent when the thickness of individual layers is less than a couple of nanometers.This review provides a detailed analysis of the effects of individual layer thickness and the interface structures on the strength and the strengthening mecha nisms of nanolaminates,their ductility and fracture behavior in terms of structural variations including grain morphologies,nanotwins,amorphous phases and crystal structures of the layers.The principles for designing nanolaminates with exceptionally high mechanical and physical properties and their fabrication are also highlighted.Some contradictory issues such as strengthening mechanisms,elastic modulus dependency on individual layer thickness and the effect of a thin amorphous layer on the strength are discussed.This review also provides future research directions in designing the high-strength nanolaminates that will facilitate practical engineering applications through analyzing up-to-date research efforts.展开更多
基金supported by Shenzhen-Hong Kong Science and Technology Innovation Cooperation Zone Shenzhen Park (Project HZQBKCZYB-2020030)National Key R&D Program of China (Project 2017YFA0204403)+2 种基金the National Natural Science Foundation of China (Project 51590892)the Major Program of Changsha Science and Technology (Project kh2003023)the Innovation and Technology Commission of HKSAR through Hong Kong Branch of National Precious Metals Material Engineering Research Centre,and the City University of Hong Kong (Project 9667207)。
文摘Surface-enhanced Raman Spectroscopy(SERS)is a nondestructive technique for rapid detection of analytes even at the single-molecule level.However,highly sensitive and reliable SERS substrates are mostly fabricated with complex nanofabrication techniques,greatly restricting their practical applications.A convenient electrochemical method for transforming the surface of commercial gold wires/foils into silver-alloyed nanostructures is demonstrated in this report.Au substrates are treated with repetitive anodic and cathodic bias in an electrolyte of thiourea,in a one-pot one-step manner.X-rays absorption fine structure(XAFS)spectroscopy confirms that the AuAg alloy is induced at the surface.The unique AuAg alloyed surface nanostructures are particularly advantageous when served as SERS substrates,enabling a remarkably sensitive detection of Rhodamine B(a detection limit of 10^(-14)M,and uniform strong response throughout the substrates at 10^(-12)M).
基金supported by the National Natural Science Foundation of China(Grant Nos.11774303 and 11574373)the financial support from“15th Graduate Research Innovation Project”from Yunnan Universityfinancial support from the Joint Fund of Yunnan Provincial Science and Technology Department(Grant No.2019FY003008)。
文摘For designing low-impedance magnetic tunnel junctions(MTJs),it has been found that tunneling magnetoresistance strongly correlates with the insulating barrier thickness,imposing a fundamental problem about the relationship between spin polarization of ferromagnet and the insulating barrier thickness in MTJs.Here,we investigate the influence of alumina barrier thickness on tunneling spin polarization(TSP)through a combination of theoretical calculations and experimental verification.Our simulating results reveal a significant impact of barrier thickness on TSP,exhibiting an oscillating decay of TSP with the barrier layer thinning.Experimental verification is realized on FeNi/AlO_(x)/Al superconducting tunnel junctions to directly probe the spin polarization of FeNi ferromagnet using Zeeman-split tunneling spectroscopy technique.These findings provide valuable insights for designs of high-performance spintronic devices,particularly in applications such as magnetic random access memories,where precise control over the insulating barrier layer is crucial.
基金Supported by the National Key Research and Development Program of China(2017YFE0300302)the National Natural Science Foundation of China(21503199,21406212)Key Project of Applied&Basic Research of Sichuan Province(18YYJC1594)
文摘The liquid phase catalytic exchange(LPCE) reaction is an effective process for heavy water detritiation and production of deuterium-depleted potable water. In the current study, hydrophobic carbon-supported platinum catalysts(Pt/C/PTFE) with high efficiency as reported previously for LPCE were prepared and comprehensive performance evaluation method is applied to evaluate the separation behaviors of LPCE systematically. Experimental results indicate that the optimum reaction temperature of 60–80℃ and the molar feed ratio G/L of 1.5–2.5 would lead to higher separation efficiencies. As to the packing method, a random packing mode with a packing ratio of hydrophobic catalysts 0.25 is recommended. In addition, thermodynamic analysis corresponds well with experimental results under lower temperature and G/L, while the suppression of kinetic factors should not be neglected when T > 80℃ and G/L > 1.5.
基金financially supported by the National Natural Science Foundation(22171212)the Science and Technology Committee of Shanghai Municipality(21160710300,19DZ2271500)of Chinathe International Exchange Grant(IEC/NSFC/201078)through Royal Society UK and NSFC。
文摘Bimetallic transition metal phosphides(TMPs)as potential candidates for superior electrochemical performance are still facing great challenges in the controllable preparation of two-dimensional(2 D)structures with high aspect ratio.Herein,a novel structure of quasi-monolayered NiCo-bimetal-phosphide(NiCoP)has been designed and successfully synthesized by the newly developed process combined with ultrasonic-cavitation and phase-transition.This is the first time to break through the controllable preparation of 2 D bimetal-phosphides with a thickness of 0.98 nm in sub-nanoscale.Based on the advantages of 2 D quasi-monolayer structure with dense crystalline-amorphous interface and the reconfigured electronic structure between Ni^(δ+)/Co^(δ+)and P^(δ-),the optimized Ni_(5%)CoP exhibits an outstanding bifunctional performance for electrocatalyzing both hydrogen evolution reaction and oxygen evolution reaction in an alkaline medium.Ni_(5%)CoP presents lower overpotentials and voltage of 84 mV&259 mV and1.48 V at the current density of 10 mA cm^(-2)for HER&DER and overall water splitting,respectively,which are superior to most other reported 2 D bimetal-phosphides.This work provides a new strategy to optimize the performance of electrolytic water for bimetal-phosphates and it may be of significant value in extending the design of other ultrathin 2 D structured catalysts.
基金supported by the National Natural Science Foundation of China (Grant Nos. 51738002 and 52108376)Fundamental Research Funds for the Central Universities (Grant No. 2021CZ111)
文摘Based on the nondestructive test data of operating railway tunnels in China, this paper summarizes the basic characteristics of the complex contact behavior between the rock mass and lining structure. The contact modes are classified into dense contact, local non-contact, and loose contact. Subsequently, the corresponding mechanical model for each contact mode is developed according to its mechanical characteristics using the complex variable method. In the proposed mechanical model, a special algorithm is introduced to detect whether the local non-contact zone is re-contacted. Besides, a novel conformal mapping method is also proposed to accurately calculate the mechanical response of the concrete lining. Finally, the accuracy of the proposed method is verified by comparing it with the finite element method(FEM). Several parameter investigations are conducted to analyze the effects of different contact modes on the rock-lining interaction. The results show that:(i) the height of the local noncontact area does not have a significant effect on the contact stress distribution if no re-contact occurs;(ii) backfill grouting can reduce the local stress concentration caused by poor contact modes;and(iii) reducing the friction coefficient of the interface can lead to a more uniform distribution of internal forces in the concrete lining.
基金This work was financially sup-ported by the National Natural Science Foundation of China(NSFC Nos:22171212,21771140,51771138,51979194)International Corporation Project of Shanghai Committee of Science and Technology by China(No.21160710300)International Exchange Grant(IEC/NSFC/201078)through Royal Society UK and NSFC.
文摘Trifunctional Cu-mesh/Cu_(2)O@FeO nanoarrays heterostructure is designed and fabricated by integrating CuCu_(2)O@FeO nanoarrays onto Cu-mesh(CM)via an in situ growth and phase transformation process.It is successfully applied to efficiently mitigate the antibiotic pollution,including degradation of antibiotics,inactivation of antibiotic-resistant bacteria(ARB),and damage of antibiotics resistance genes(ARGs).Under visible-light irradiation,CM/CuCu_(2)O@FeO nanoarrays exhibit a superior degradation efficiency on antibiotics(e.g.,up to 99%in 25 min for tetracycline hydrochloride,TC),due to the generated reactive oxygen species(ROS),especially the dominant·O^(2−).It can fully inactivate E.coli(HB101)with initial number of~108 CFU mL^(−1) in 10 min,which is mainly attributed to the synergistic effects of 1D nanostructure,dissolved metal ions,and generated ROS.Meanwhile,it is able to damage ARGs after 180 min of photodegradation,including tetA(vs TC)of 3.3 log 10,aphA(vs kanamycin sulfate,KAN)of 3.4 log 10,and tnpA(vs ampicillin,AMP)of 4.4 log 10,respectively.This work explores a green way for treating antibiotic pollution under visible light.
基金Supported by National Natural Science Foundation of China(31260607,31560703)Guizhou Provincial Hundred-level Innovative Talent Project(QKHRC20164009)Guizhou Provincial Science and Technology Platform and Talent Team Planning Project(QKHPTRC20185253)。
文摘[Objectives] This study was conducted to understand the current status of duck related research. [Methods] CiteSpace knowledge graph analysis tool, VOSviewer visual analysis software and HistCite citation graph analysis tool were used to analyze the number of publications and subject distribution of duck-related research fields in the Web of Science core collection database. The main countries(regions) and institutions, the main academic journals, the main research scholars, the main research hotspots and their changing trends were used for quantitative analysis. [Results](1) Duck-related research is receiving more and more attention, which further supports ducks’ important significance in the livestock and poultry industry.(2) Countries such as China, the United States, Canada, and France had published more articles in this field, and there was close cooperation between countries.(3) The top two journals with local citations in the duck-related research fields were PLOS ONE and JOURNAL OF VIROLOGY, and the journal with the highest impact factor in 2019 was JOURNAL OF VIROLOGY.(4) High-yield scholars in duck related research fields included Cheng Anchun, Wang Mingshu, Jia Renyong, etc.(5) Infection was a research hotspot in duck-related research. Typical pathogenic microorganisms included Newcastle disease, Avian influenza, and campylobacter.(6) The future trend of duck-related research mainly focuses on breeds, living environment, diseases, and molecular mechanisms. [Conclusions] Based on data from the Web of Science core collection database, this paper provides a complete bibliometric analysis of the current research status of ducks.
文摘Background: The aim of this study was to investigate the distribution of the c-erbB2 antisense probe labeled with superparamagnetic iron oxide nanoparticles in the major organs of mice by MR imaging. Methods: Sixty BALB/c mice were randomly divided into experimental and control groups. MR scans were performed in each mouse of the experimental group at five different time points (10, 30, 60, 180 and 360 min) after injection of the antisense probe. The signal from each major organ (liver, spleen, heart, kidney and muscle tissue) in comparison with the background signal (signal to noise ratio) was determined at each time point as a measure of the distribution of the antisense probe. Six control mice were killed at each of the same time points and the organs immediately removed for determination of their iron content. Results: After injection of the antisense probe, the highest enrichment of the probe was seen in the spleen, reaching a peak at 180 min, followed by the liver, muscle, heart and kidney. Conclusions: MR imaging can visualize the distribution of c-erbB2 antisense probe labeled with superparamagnetic iron oxide nanoparticles in the major organs of mice, and this may provide the basis for further in vivo studies of MR imaging time and dose selection.
基金supported by SGCC Scientific and Technological Project(5216A018000J)National Key R&D Program of China(2016YFB0900900)
文摘The system controlled in synchronous frame is commonly used. However, it is a problem how to transform the controller in synchronous frame to stationary frame. This paper deduces the stationary frame equivalent model of arbitrarily controller in synchronous frame. The equivalent model can reflect the control performance of the input signal at different frequency accurately. The unified frequency-domain model of the overall system can be established using the equivalent model, and the guidance for frequency analysis and stability analysis can be provided. Theoretical derivation and simulation results verify the correctness and generality of the equivalent model.
基金financial support for this research by the Australian Research Council (ARC) through the Discovery Project (DP170102557)Future Fellowship (FT160100252)National Health and Medical Research Council (NHMRC), Australia through project grant (GNT1087290)。
文摘Nanolaminates are composed of nanoscale-thick alternating layers of different materials and their properties are dependent on the individual layers,the layer thickness and the interfaces between the layers.Nanolaminates composed of cubic crystal structured metals are usually ductile compared to nanolaminates containing hexagonal crystal structured metals.Mechanical properties such as strength and hardness of nanolaminates increase with a decrease in individual layer thickness down to a few nanometers and they become independent when the thickness of individual layers is less than a couple of nanometers.This review provides a detailed analysis of the effects of individual layer thickness and the interface structures on the strength and the strengthening mecha nisms of nanolaminates,their ductility and fracture behavior in terms of structural variations including grain morphologies,nanotwins,amorphous phases and crystal structures of the layers.The principles for designing nanolaminates with exceptionally high mechanical and physical properties and their fabrication are also highlighted.Some contradictory issues such as strengthening mechanisms,elastic modulus dependency on individual layer thickness and the effect of a thin amorphous layer on the strength are discussed.This review also provides future research directions in designing the high-strength nanolaminates that will facilitate practical engineering applications through analyzing up-to-date research efforts.
