目的系统评价有氧结合抗阻运动在卵巢癌患者中的干预效果。方法计算机检索PubMed、Cochrane Library、Embase、Web of Science、知网、维普、万方、中国生物医学文献服务系统等数据库中有关有氧结合抗阻运动对卵巢癌患者干预效果的随机...目的系统评价有氧结合抗阻运动在卵巢癌患者中的干预效果。方法计算机检索PubMed、Cochrane Library、Embase、Web of Science、知网、维普、万方、中国生物医学文献服务系统等数据库中有关有氧结合抗阻运动对卵巢癌患者干预效果的随机对照试验(randomized controlled trial,RCT)或类试验,检索时限从建库至2024年1月9日。由2名研究人员进行独立筛选、数据提取和质量评价,采用RevMan 5.4软件进行meta分析。结果共纳入6篇文献,包括3项RCT和3项类实验,共444例患者。meta分析结果显示,有氧结合抗阻运动能够缓解患者癌因性疲乏[SMD=-0.85,95%CI(-1.50,-0.20),P=0.01];改善患者的情绪功能[SMD=0.25,95%CI(0.03,0.47),Z=2.21,P=0.03]、身体功能[SMD=0.50,95%CI(0.28,0.73),Z=4.38,P<0.001]、社会功能[SMD=0.23,95%CI(0.00,0.45),Z=2.00,P=0.05];但肌肉力量证据不足,其他指标如健康相关生活质量、睡眠质量、最大摄氧量差异无统计学意义(P>0.05)。结论有氧结合抗阻运动能缓解卵巢癌患者的癌因性疲乏,改善其情绪功能、身体功能和社会功能,可为临床医护人员开展运动干预提供参考。展开更多
Al-FeCoNiCrAl high entropy alloy(HEA) composite coatings were prepared on Ti-6Al-4V via highenergy mechanical alloying(MA). The microstructures and phase composition of the coatings were studied. A continuous and dens...Al-FeCoNiCrAl high entropy alloy(HEA) composite coatings were prepared on Ti-6Al-4V via highenergy mechanical alloying(MA). The microstructures and phase composition of the coatings were studied. A continuous and dense coating could be fabricated at a ratio of 35%(weight fraction)Al-FeCoNiCrAl after 4 h milling.The results showed that the thickness of the composite coatings increased first and then decreased with the increase of milling time. And the hardness of coating increased with the increase of milling time. The phase changed during the annealing process. Part of the initial body-centered cubic(BCC)phase of the composite coatings changed into the L12 phase,(Ni,Co)3Al4 and σ phase after annealing above 550 ℃. Ordered BCC was found in the coatings after annealing above 750 ℃. Only BCC and ordered BCC appeared in coatings after annealing above 1 050 ℃. The hardness of the coatings after annealing at 550 ℃ and 750 ℃ was higher than before because of spinodal decomposition and high hardness σ phase. The hardness of the coatings after annealing at 1 050 ℃ decreased because residual stress released.展开更多
Lithium sulfur(Li-S)batteries are poised to be the next generation of high-density energy storage devices.In recent years,the concept of“electrocatalysis”has been introduced into the field of Li-S batteries,and some...Lithium sulfur(Li-S)batteries are poised to be the next generation of high-density energy storage devices.In recent years,the concept of“electrocatalysis”has been introduced into the field of Li-S batteries,and some transition metals have been proved to catalyze the electrochemical conversion reaction of sulfur species.In this study,carbon encapsulated nickel nanoparticles(Ni@C)with a specific surface area of 146 m^(2)/g are shown to play a definitive electrocatalytic role for the sulfur cathode.With Ni@C incorporated,the Ni@C/G-S electrode achieved a better electrochemical performance than the G-S electrode.Moreover,the reversible capacity and cycle stability were further improved through chemical modifications of the carbon shell.The influence of doping with different elements on the Li-S battery performance was also investigated in detail.Higher specific capacities of 1229 mA·h/g,927 mA·h/g,and 830 mA·h/g were achieved at 0.2 C,0.5 C,and 1.0 C for the N-Ni@C-G/S electrode.Besides,the B-Ni@C-G/S electrode possessed a best cycle stability.展开更多
We investigate the luminescence properties of erbium-doped and erbium-ytterbium-codoped potassium lithium tantalate niobate ceramics prepared by the solid phasesyntheses method.The crystalline structure and surface mo...We investigate the luminescence properties of erbium-doped and erbium-ytterbium-codoped potassium lithium tantalate niobate ceramics prepared by the solid phasesyntheses method.The crystalline structure and surface morphology of these ceramics are tested by x-ray diffraction and scanning electron microscopy.The green,red,and near-infrared upconversion photoluminescence properties are analyzed by the steady-state spectra under 975 nm and 800 nm excitations.These ceramics arewell sintered and tetragonal tungsten type crystalline structure with the 4 mm point group and the P4bm space group.The Er3+upconversion emission integrated intensities increase with theincrease in Er3+ion concentration,while the green emissiondecreases with the increase in Yb^(3+)ion concentration under the 800 nm excitation.An effective energy back transfer process from the Er^(3+)^(4)S_(3/2)state to Yb^(3+)ground state plays an important role in enhancing the red emission and weakening the green emission.展开更多
文摘Al-FeCoNiCrAl high entropy alloy(HEA) composite coatings were prepared on Ti-6Al-4V via highenergy mechanical alloying(MA). The microstructures and phase composition of the coatings were studied. A continuous and dense coating could be fabricated at a ratio of 35%(weight fraction)Al-FeCoNiCrAl after 4 h milling.The results showed that the thickness of the composite coatings increased first and then decreased with the increase of milling time. And the hardness of coating increased with the increase of milling time. The phase changed during the annealing process. Part of the initial body-centered cubic(BCC)phase of the composite coatings changed into the L12 phase,(Ni,Co)3Al4 and σ phase after annealing above 550 ℃. Ordered BCC was found in the coatings after annealing above 750 ℃. Only BCC and ordered BCC appeared in coatings after annealing above 1 050 ℃. The hardness of the coatings after annealing at 550 ℃ and 750 ℃ was higher than before because of spinodal decomposition and high hardness σ phase. The hardness of the coatings after annealing at 1 050 ℃ decreased because residual stress released.
基金This work was financially supported by the China Petrochemical Corporation(218025-9).
文摘Lithium sulfur(Li-S)batteries are poised to be the next generation of high-density energy storage devices.In recent years,the concept of“electrocatalysis”has been introduced into the field of Li-S batteries,and some transition metals have been proved to catalyze the electrochemical conversion reaction of sulfur species.In this study,carbon encapsulated nickel nanoparticles(Ni@C)with a specific surface area of 146 m^(2)/g are shown to play a definitive electrocatalytic role for the sulfur cathode.With Ni@C incorporated,the Ni@C/G-S electrode achieved a better electrochemical performance than the G-S electrode.Moreover,the reversible capacity and cycle stability were further improved through chemical modifications of the carbon shell.The influence of doping with different elements on the Li-S battery performance was also investigated in detail.Higher specific capacities of 1229 mA·h/g,927 mA·h/g,and 830 mA·h/g were achieved at 0.2 C,0.5 C,and 1.0 C for the N-Ni@C-G/S electrode.Besides,the B-Ni@C-G/S electrode possessed a best cycle stability.
文摘单电感双输出(single-inductor dual-output,SIDO)开关变换器工作在共享充放时序下存在电感电流纹波大、输出支路间交叉影响严重以及电路参数宽范围变化下控制电路不能正常工作等问题.为此,提出一种独立充放时序电流型变频控制(current-mode variable frequency control,C-VF)技术.首先,具体描述变换器在连续导电模式(continuous conduction mode,CCM)下的工作原理,并推导主电路开环传递函数;进一步构建闭环小信号模型,推导闭环交叉阻抗,详细分析不同输出电压及负载电流下变换器的交叉影响特性;最后,通过仿真和实验进行验证.研究表明:相较于共享充放时序,独立充放时序C-VF CCM SIDO buck变换器减小了交叉影响,改善了负载瞬态响应性能;当两支路负载电压不等时,减轻某一支路负载可以降低该支路的交叉影响;当两支路输出电压相同但负载不同时,重载支路对轻载支路的交叉影响更小.
基金Supported by the National Natural Science Foundation of China under Grant No 11074059the Fundamental Research Funds for the Central Universities of China under Grant No Bzx/13b101-06.
文摘We investigate the luminescence properties of erbium-doped and erbium-ytterbium-codoped potassium lithium tantalate niobate ceramics prepared by the solid phasesyntheses method.The crystalline structure and surface morphology of these ceramics are tested by x-ray diffraction and scanning electron microscopy.The green,red,and near-infrared upconversion photoluminescence properties are analyzed by the steady-state spectra under 975 nm and 800 nm excitations.These ceramics arewell sintered and tetragonal tungsten type crystalline structure with the 4 mm point group and the P4bm space group.The Er3+upconversion emission integrated intensities increase with theincrease in Er3+ion concentration,while the green emissiondecreases with the increase in Yb^(3+)ion concentration under the 800 nm excitation.An effective energy back transfer process from the Er^(3+)^(4)S_(3/2)state to Yb^(3+)ground state plays an important role in enhancing the red emission and weakening the green emission.
