The formation of periodic layered structure in Ni3Si/Zn diffusion couples with Zn in vapor or liquid state was investigated by SEM-EDS, FESEM and XRD. The results show that the diffusion path in solid-liquid reaction ...The formation of periodic layered structure in Ni3Si/Zn diffusion couples with Zn in vapor or liquid state was investigated by SEM-EDS, FESEM and XRD. The results show that the diffusion path in solid-liquid reaction is Ni3Si/（T＋γ）/γ/…T/γ/Ni4Zn12Si3/γ/…Ni4Zn12Si3/γ/Ni4Zn12Si3/δ…/Ni4Zn12Si3/δ/liquid-Zn, and the diffusion path in solid-vapor reaction is Ni3Si/θ/（T＋γ）/γ/…/T/γ/…T/γ/vapor-Zn. With increasing Zn diffusion flux, the diffusion reaction path moves toward the Zn-rich direction, and the distance from the Ni3Si substrate to the periodic layer pair nearest to the interface decreases. In the initial stage of both reactions,γphase nucleates and grows within T matrix phase at first, and then conjuncts together to form a band to reduce the surface energy. Based on the experimental results and diffusion kinetics analysis, the microstructure differences were compared and the formation mechanism of the periodic layered structure in Ni3Si/Zn system was discussed.展开更多
OBJECTIVE:To assess the clinical effectiveness and adverse effects of Yinchenwuling powder(YCWLP)in the treatment of hyperlipidemia using Meta-analysis.METHODS:Seven electronic databases were searched for randomized c...OBJECTIVE:To assess the clinical effectiveness and adverse effects of Yinchenwuling powder(YCWLP)in the treatment of hyperlipidemia using Meta-analysis.METHODS:Seven electronic databases were searched for randomized controlled trials designed to evaluate the clinical effectiveness of YCWLP for hyperlipidemia published in any language prior to February 2015.Two reviewers independently identified articles,extracted data,assessed quality,and cross-checked the results.Revman 5.3 was used to analyze the data.RESULTS:Only five randomized controlled trials with poor methodology were included in the analy-sis.The five trials compared YCWLP with conventional lipid-lowering drugs.Meta-analysis indicated that YCWLP was more effective at the levels of total cholesterol and triglycerides,while increasing the level of high-density lipoprotein cholesterol without serious adverse effects.However,it was not more effective than lipid-lowering drugs in reducing low-density lipoprotein cholesterol and improving hemorheology.CONCLUSION:YCWLP appeared to improve lipid levels.However,given the high risk of bias among the trials,we could not conclude that YCWLP was beneficial to patients with hyperlipidemia.More rigorous trials are required to provide stronger evidence for the conclusion.展开更多
In this paper, the phenomenon that the variation in nutrient and water temperature could cause changes in phytoplankton growth and structure is examined; and the question of how a marine ecosystem make up the earth ec...In this paper, the phenomenon that the variation in nutrient and water temperature could cause changes in phytoplankton growth and structure is examined; and the question of how a marine ecosystem make up the earth ecosystem step by step to auto-sustain the balance between phytoplankton and nutrient supply especially Si is discussed. Three major complementary mechanisms of the earth ecosys- tem for nutrient Si, water temperature and carbon were put forward. Understanding the mechanisms nowadays would explain the why the El Nifio and La Nifia occurred, and forecast the trend of human-impacted the earth, which would alert us with proactive countermeasures.展开更多
The effects of yttrium and cerium on microstructures and properties of Nb-Si system composites were investigated by scanning electron microscopy( SEM), energy dispersive spectrum(EDS), X-ray diffraction(XRD) and high ...The effects of yttrium and cerium on microstructures and properties of Nb-Si system composites were investigated by scanning electron microscopy( SEM), energy dispersive spectrum(EDS), X-ray diffraction(XRD) and high temperature oxidation experiments.It is found that the coarse primary silicide phase became finer and more homogeneous with Y and Ce addition.The results of high temperature oxidation experiments show that the oxidation rates of NbSi system composites with an appropriate amount of Y and Ce decrease compared with those of alloys without Y or Ce addition, and oxidation products mainly distribute along the phase boundaries between the Nb solid solution and silicide.展开更多
High peak-to-average power ratio(PAPR) is a concern in orthogonal frequency division multiplexing(OFDM) systems. Hadamard based selected mapping(HSLM) which uses Hadamard code as the phase sequence in selected mapping...High peak-to-average power ratio(PAPR) is a concern in orthogonal frequency division multiplexing(OFDM) systems. Hadamard based selected mapping(HSLM) which uses Hadamard code as the phase sequence in selected mapping(SLM) is an attractive technique to reduce PAPR. But it requires sending side information(SI) to the receiver for each data block, and this results in a reduction in bandwidth efficiency. In this paper, we proposed a modified PAPR reduction method called semi-Hadamard based selected mapping(semi-HSLM) to decouple the phase information matrix into a phase rotation matrix for PAPR reduction and a SI matrix for side information hiding. We proposed a semi-hadamard matrix generation method to generate the phase rotation matrix, and designed a cyclic shift matrix as the SI matrix. Compared with the traditional HSLM, the semi-HSLM saves half of the phase storage and achieves good PAPR reduction performance.展开更多
Martensitic transformation is significant to strengthen steels,but its thermodynamic prediction is restricted to simple systems due to lacking multicomponent interaction parameters.The driving forces of martensitic tr...Martensitic transformation is significant to strengthen steels,but its thermodynamic prediction is restricted to simple systems due to lacking multicomponent interaction parameters.The driving forces of martensitic transformation can be divided into chemical and non-chemical driving forces.The magnetic parameters are carefully optimized because it affects the magnetic Gibbs free energy of austenite and ferrite,and have big impact on the chemical driving force.The dilatational strain energy provides major contribution to non-chemical driving force,thus the integrated-models for dilatational coefficient are constructed in a wide composition and temperature range based on the experimental dilatational data.It expands the scope of application of thermodynamic model and improved prediction accuracy of martensitic transformation temperature(M_(s)).The prediction error reaches 5.6%for Fe-C-X(X=Ni,Mn,Si,Cr)and6.5%for Fe-C-Mn-Si-X(X=Cr,Ni)steels.展开更多
Thermoelectric materials, Mg2Si1-xGex （x=0, 0.2, 0.4, 0.6, 0.8, 1）, have been prepared by bulk mechanical alloying （BMA） and hot pressing （HP）. The electrical conductivity, Seebeck coefficient and thermal conduc...Thermoelectric materials, Mg2Si1-xGex （x=0, 0.2, 0.4, 0.6, 0.8, 1）, have been prepared by bulk mechanical alloying （BMA） and hot pressing （HP）. The electrical conductivity, Seebeck coefficient and thermal conductivity were measured from room temperature up to about 700 K. The electrical conductivity of all the samples increases with increasing temperature, while the Seebeck coefficient and thermal conductivity decrease with increasing temperature. Mg2Si and Mg2Si0.8Ge0.2 possess negative type of conductivity, while for other compounds it is positive. At the same time, the effect of hot processing condition on thermoelectric properties was also investigated. The maximum figure of merit of Mg2Si0.6Ge0.4 was obtained with the processing parameter of BMA at 600 cycles and hot pressing at 773 K and i GPa for i h.展开更多
In this paper, we design a novel three-order autonomous system. Numerical simulations reveal the complex chaotic behaviors of the system. By applying the undetermined coefficient method, we find a heteroclinic orbit i...In this paper, we design a novel three-order autonomous system. Numerical simulations reveal the complex chaotic behaviors of the system. By applying the undetermined coefficient method, we find a heteroclinic orbit in the system. As a result, the Si＇lnikov criterion along with some other given conditions guarantees that the system has both Smale horseshoes and chaos of horseshoe type.展开更多
An ion beam analysis system was established on a 1.7 MV tandem accelerator, enabling Rutherford backscattering(RBS), elastic recoil detection(ERD), nuclear reaction analysis(NRA) and channeling measurements. The syste...An ion beam analysis system was established on a 1.7 MV tandem accelerator, enabling Rutherford backscattering(RBS), elastic recoil detection(ERD), nuclear reaction analysis(NRA) and channeling measurements. The system was tested by performing qualitative and quantitative analysis of Si, Ni/Si, Bi Fe O3:La/Si,Mo C/Mo/Si and Ti BN/Si samples. RBS of a Bi Fe O3:La film was used as system calibration. Tested by ion beam channeling, a Si(100) is of good crystallinity(χmin= 3.01%). For thin film samples, the measured thickness agrees well with simulation results by SIMNRA. In particular, composition of a Mo C/Mo/Si and Ti BN film samples were analyzed by RBS and non-Rutherford elastic backscattering.展开更多
Introduction:Robotic systems are designed to address the limitations of laparoscopic surgery,leading to a growing interest in robotic rectal surgery.However,certain technical limitations associated with the previous s...Introduction:Robotic systems are designed to address the limitations of laparoscopic surgery,leading to a growing interest in robotic rectal surgery.However,certain technical limitations associated with the previous systems(da Vinci S&Si)have arguably slowed down its wholesale adoption.The latest robotic platform,the da Vinci Xi,addresses these limitations.This study aims to examine the short-term surgical outcomes of 240 single-docking fully-robotic rectal cancer resections and compare the outcomes of cases performed with the da Vinci Xi vs Si systems.Materials and methods:All consecutive patients receiving robotic rectal cancer resections from three centres between 2013 and 2018 were identified from prospectively collated databases.The baseline characteristics and short-term surgical outcomes are presented and the da Vinci Xi vs Si system outcomes are analysed.Results:A total of 240 patients were identified(124 Si,116 Xi).Median operation-time and length-of-stay were 260 minutes and 6 days respectively.Conversion and 30-day mortality rates were 0.The da Vinci Si vs Xi system analysis shows that operation-time was lower in the Si group(230 vs 300 min,p=0.000)but length-of-stay,lymph node yield and circumferential resection margin favoured the Xi group(7 vs 5 days,p=0.010;17 vs 21,p=0.000;92.7%vs 99.1%,p=0.020).Conclusion:Single-docking fully-robotic rectal cancer surgery is safe,feasible and can lead to good shortterm outcomes,making it a good alternative to laparoscopic rectal cancer surgery.The new systems technological advances may result in better short-term outcomes but further larger scale observational studies are required if we are to reach such a conclusion.展开更多
A new phase with the appropriate composition of Ti_3Co_2Si is found to exist at 1100℃. The X-ray diffraction of this phase can not be indexed by any other phase in the Ti-Co-Si ternary system and show this phase to b...A new phase with the appropriate composition of Ti_3Co_2Si is found to exist at 1100℃. The X-ray diffraction of this phase can not be indexed by any other phase in the Ti-Co-Si ternary system and show this phase to be hexagonal with the lattice parameter of α=0.676 nm, c=0.732 nm, c/α=1.0825.展开更多
基金Projects(51271040,51171031)supported by the National Natural Science Foundation of ChinaProject supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘The formation of periodic layered structure in Ni3Si/Zn diffusion couples with Zn in vapor or liquid state was investigated by SEM-EDS, FESEM and XRD. The results show that the diffusion path in solid-liquid reaction is Ni3Si/（T＋γ）/γ/…T/γ/Ni4Zn12Si3/γ/…Ni4Zn12Si3/γ/Ni4Zn12Si3/δ…/Ni4Zn12Si3/δ/liquid-Zn, and the diffusion path in solid-vapor reaction is Ni3Si/θ/（T＋γ）/γ/…/T/γ/…T/γ/vapor-Zn. With increasing Zn diffusion flux, the diffusion reaction path moves toward the Zn-rich direction, and the distance from the Ni3Si substrate to the periodic layer pair nearest to the interface decreases. In the initial stage of both reactions,γphase nucleates and grows within T matrix phase at first, and then conjuncts together to form a band to reduce the surface energy. Based on the experimental results and diffusion kinetics analysis, the microstructure differences were compared and the formation mechanism of the periodic layered structure in Ni3Si/Zn system was discussed.
基金Supported by the Chinese National Natural Science Foundation Key Project(Identification of the Molecular Signature Contributing to the Susceptibility of Phlegmatic Hygrosis Constitution to Metabolic Syndrome,No.81030064)
文摘OBJECTIVE:To assess the clinical effectiveness and adverse effects of Yinchenwuling powder(YCWLP)in the treatment of hyperlipidemia using Meta-analysis.METHODS:Seven electronic databases were searched for randomized controlled trials designed to evaluate the clinical effectiveness of YCWLP for hyperlipidemia published in any language prior to February 2015.Two reviewers independently identified articles,extracted data,assessed quality,and cross-checked the results.Revman 5.3 was used to analyze the data.RESULTS:Only five randomized controlled trials with poor methodology were included in the analy-sis.The five trials compared YCWLP with conventional lipid-lowering drugs.Meta-analysis indicated that YCWLP was more effective at the levels of total cholesterol and triglycerides,while increasing the level of high-density lipoprotein cholesterol without serious adverse effects.However,it was not more effective than lipid-lowering drugs in reducing low-density lipoprotein cholesterol and improving hemorheology.CONCLUSION:YCWLP appeared to improve lipid levels.However,given the high risk of bias among the trials,we could not conclude that YCWLP was beneficial to patients with hyperlipidemia.More rigorous trials are required to provide stronger evidence for the conclusion.
基金Supported by the Director’s Foundation of the Beihai Monitoring Cen-ter, the State Oceanic Administration, and Chinese Academy of Sciences (KZCX 2-207).
文摘In this paper, the phenomenon that the variation in nutrient and water temperature could cause changes in phytoplankton growth and structure is examined; and the question of how a marine ecosystem make up the earth ecosystem step by step to auto-sustain the balance between phytoplankton and nutrient supply especially Si is discussed. Three major complementary mechanisms of the earth ecosys- tem for nutrient Si, water temperature and carbon were put forward. Understanding the mechanisms nowadays would explain the why the El Nifio and La Nifia occurred, and forecast the trend of human-impacted the earth, which would alert us with proactive countermeasures.
基金Project supported by Areonautical Science Foundation of China(03G21003 )
文摘The effects of yttrium and cerium on microstructures and properties of Nb-Si system composites were investigated by scanning electron microscopy( SEM), energy dispersive spectrum(EDS), X-ray diffraction(XRD) and high temperature oxidation experiments.It is found that the coarse primary silicide phase became finer and more homogeneous with Y and Ce addition.The results of high temperature oxidation experiments show that the oxidation rates of NbSi system composites with an appropriate amount of Y and Ce decrease compared with those of alloys without Y or Ce addition, and oxidation products mainly distribute along the phase boundaries between the Nb solid solution and silicide.
基金the Wireless Network Positioning and Communication Integration Research Center in BUPT for financial support
文摘High peak-to-average power ratio(PAPR) is a concern in orthogonal frequency division multiplexing(OFDM) systems. Hadamard based selected mapping(HSLM) which uses Hadamard code as the phase sequence in selected mapping(SLM) is an attractive technique to reduce PAPR. But it requires sending side information(SI) to the receiver for each data block, and this results in a reduction in bandwidth efficiency. In this paper, we proposed a modified PAPR reduction method called semi-Hadamard based selected mapping(semi-HSLM) to decouple the phase information matrix into a phase rotation matrix for PAPR reduction and a SI matrix for side information hiding. We proposed a semi-hadamard matrix generation method to generate the phase rotation matrix, and designed a cyclic shift matrix as the SI matrix. Compared with the traditional HSLM, the semi-HSLM saves half of the phase storage and achieves good PAPR reduction performance.
基金financially supported by the National Natural Science Foundation of China(Nos.U1808208 and 51734002)the Independent Research and Development Project of State Key Laboratory of Advanced Special Steel,Shanghai Key Laboratory of Advanced Ferrometallurgy,Shanghai University(No.SKLASS 2020Z01)the Science and Technology Commission of Shanghai Municipality(No.19DZ2270200)。
文摘Martensitic transformation is significant to strengthen steels,but its thermodynamic prediction is restricted to simple systems due to lacking multicomponent interaction parameters.The driving forces of martensitic transformation can be divided into chemical and non-chemical driving forces.The magnetic parameters are carefully optimized because it affects the magnetic Gibbs free energy of austenite and ferrite,and have big impact on the chemical driving force.The dilatational strain energy provides major contribution to non-chemical driving force,thus the integrated-models for dilatational coefficient are constructed in a wide composition and temperature range based on the experimental dilatational data.It expands the scope of application of thermodynamic model and improved prediction accuracy of martensitic transformation temperature(M_(s)).The prediction error reaches 5.6%for Fe-C-X(X=Ni,Mn,Si,Cr)and6.5%for Fe-C-Mn-Si-X(X=Cr,Ni)steels.
文摘Thermoelectric materials, Mg2Si1-xGex （x=0, 0.2, 0.4, 0.6, 0.8, 1）, have been prepared by bulk mechanical alloying （BMA） and hot pressing （HP）. The electrical conductivity, Seebeck coefficient and thermal conductivity were measured from room temperature up to about 700 K. The electrical conductivity of all the samples increases with increasing temperature, while the Seebeck coefficient and thermal conductivity decrease with increasing temperature. Mg2Si and Mg2Si0.8Ge0.2 possess negative type of conductivity, while for other compounds it is positive. At the same time, the effect of hot processing condition on thermoelectric properties was also investigated. The maximum figure of merit of Mg2Si0.6Ge0.4 was obtained with the processing parameter of BMA at 600 cycles and hot pressing at 773 K and i GPa for i h.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61170037 and 61074192)
文摘In this paper, we design a novel three-order autonomous system. Numerical simulations reveal the complex chaotic behaviors of the system. By applying the undetermined coefficient method, we find a heteroclinic orbit in the system. As a result, the Si＇lnikov criterion along with some other given conditions guarantees that the system has both Smale horseshoes and chaos of horseshoe type.
基金Supported by the National Natural Science Foundation of China(No.11405117)the State Key Lab of Advanced Welding and Joining of Harbin Institute of Technology(No.AWJ-M13-03)
文摘An ion beam analysis system was established on a 1.7 MV tandem accelerator, enabling Rutherford backscattering(RBS), elastic recoil detection(ERD), nuclear reaction analysis(NRA) and channeling measurements. The system was tested by performing qualitative and quantitative analysis of Si, Ni/Si, Bi Fe O3:La/Si,Mo C/Mo/Si and Ti BN/Si samples. RBS of a Bi Fe O3:La film was used as system calibration. Tested by ion beam channeling, a Si(100) is of good crystallinity(χmin= 3.01%). For thin film samples, the measured thickness agrees well with simulation results by SIMNRA. In particular, composition of a Mo C/Mo/Si and Ti BN film samples were analyzed by RBS and non-Rutherford elastic backscattering.
文摘Introduction:Robotic systems are designed to address the limitations of laparoscopic surgery,leading to a growing interest in robotic rectal surgery.However,certain technical limitations associated with the previous systems(da Vinci S&Si)have arguably slowed down its wholesale adoption.The latest robotic platform,the da Vinci Xi,addresses these limitations.This study aims to examine the short-term surgical outcomes of 240 single-docking fully-robotic rectal cancer resections and compare the outcomes of cases performed with the da Vinci Xi vs Si systems.Materials and methods:All consecutive patients receiving robotic rectal cancer resections from three centres between 2013 and 2018 were identified from prospectively collated databases.The baseline characteristics and short-term surgical outcomes are presented and the da Vinci Xi vs Si system outcomes are analysed.Results:A total of 240 patients were identified(124 Si,116 Xi).Median operation-time and length-of-stay were 260 minutes and 6 days respectively.Conversion and 30-day mortality rates were 0.The da Vinci Si vs Xi system analysis shows that operation-time was lower in the Si group(230 vs 300 min,p=0.000)but length-of-stay,lymph node yield and circumferential resection margin favoured the Xi group(7 vs 5 days,p=0.010;17 vs 21,p=0.000;92.7%vs 99.1%,p=0.020).Conclusion:Single-docking fully-robotic rectal cancer surgery is safe,feasible and can lead to good shortterm outcomes,making it a good alternative to laparoscopic rectal cancer surgery.The new systems technological advances may result in better short-term outcomes but further larger scale observational studies are required if we are to reach such a conclusion.
文摘A new phase with the appropriate composition of Ti_3Co_2Si is found to exist at 1100℃. The X-ray diffraction of this phase can not be indexed by any other phase in the Ti-Co-Si ternary system and show this phase to be hexagonal with the lattice parameter of α=0.676 nm, c=0.732 nm, c/α=1.0825.
