期刊文献+
共找到261,373篇文章
< 1 2 250 >
每页显示 20 50 100
Ablation behaviour and mechanical performance of ZrB_(2)-ZrC-SiC modified carbon/carbon composites prepared by vacuum infiltration combined with reactive melt infiltration
1
作者 ZHANG Jia-ping SU Xiao-xuan +2 位作者 LI Xin-gang WANG Run-ning FU Qian-gang 《新型炭材料(中英文)》 SCIE EI CAS CSCD 北大核心 2024年第4期633-644,共12页
The development of advanced aircraft relies on high performance thermal-structural materials,and carbon/carbon com-posites(C/C)composited with ultrahigh-temperature ceramics are ideal candidates.However,the traditiona... The development of advanced aircraft relies on high performance thermal-structural materials,and carbon/carbon com-posites(C/C)composited with ultrahigh-temperature ceramics are ideal candidates.However,the traditional routes of compositing are either inefficient and expensive or lead to a non-uniform distribution of ceramics in the matrix.Compared with the traditional C/C-ZrC-SiC composites prepared by the reactive melt infiltration of ZrSi_(2),C/C-ZrB_(2)-ZrC-SiC composites prepared by the vacuum infiltration of ZrB_(2) combined with reactive melt infiltration have the higher content and more uniform distribution of the introduced ceramic phases.The mass and linear ablation rates of the C/C-ZrB_(2)-ZrC-SiC composites were respectively 68.9%and 29.7%lower than those of C/C-ZrC-SiC composites prepared by reactive melt infiltration.The ablation performance was improved because the volatilization of B_(2)O_(3),removes some of the heat,and the more uniformly distributed ZrO_(2),that helps produce a ZrO2-SiO2 continu-ous protective layer,hinders oxygen infiltration and decreases ablation. 展开更多
关键词 c/c composites ZrB_(2)-Zrc-Sic Vacuum filtration Reactive melt infiltration Ablation.
下载PDF
Effect of Heat Treatment on Microstructure and Mechanical Properties of Multiscale SiC_p Hybrid Reinforced 6061 Aluminum Matrix Composites
2
作者 吴健铭 许晓静 +3 位作者 ZHANG Xu LUO Yuntian LI Shuaidi HUANG Lin 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第1期174-181,共8页
The performance of solid solution aging treatment on aluminum matrix composites prepared by powder metallurgy and reinforced with 6061 aluminum alloy powder as matrix;meanwhile, nano silicon carbide particles(nm Si Cp... The performance of solid solution aging treatment on aluminum matrix composites prepared by powder metallurgy and reinforced with 6061 aluminum alloy powder as matrix;meanwhile, nano silicon carbide particles(nm Si Cp), submicron silicon carbide particles(1 μm Si Cp) and Ti particles were studied. The Al/Si Cp composite powder was prepared by high-energy ball milling, and then cold-pressed, sintered, hotextruded, and then heat-treated with different solution temperatures and aging times for the extruded composites. Optical microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy(EDS), X-ray diffractometer(XRD) and extrusion testing were used to analyze and test the microstructure and mechanical properties of aluminum matrix composites. The results show that after the multi-stage solid solution at 530 ℃×2 h+535 ℃×2 h+540 ℃×2 h, the particles are mainly equiaxed grains and uniformly distributed. There is no reinforcement agglomeration, and the surface is dense and the insoluble phase is basically dissolved. In the matrix, the strengthening effect is good, and the hardness and compressive strength are 179.43 HV and 680.42 MPa, respectively. Under this solution process, when the aluminum matrix composites are aged at 170 ℃ for 10 h, the hardness and compressive strength can reach their peaks and increase to 195.82 HV and 721.48 MPa, respectively. 展开更多
关键词 aluminum matrix composites Si c particles multiscale hybrid enhancement heat treatment mechanical properties
下载PDF
Multi-scale Modeling and Finite Element Analyses of Thermal Conductivity of 3D C/SiC Composites Fabricating by Flexible-Oriented Woven Process
3
作者 Zheng Sun Zhongde Shan +5 位作者 Hao Huang Dong Wang Wang Wang Jiale Liu Chenchen Tan Chaozhong Chen 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2024年第3期275-288,共14页
Thermal conductivity is one of the most significant criterion of three-dimensional carbon fiber-reinforced SiC matrix composites(3D C/SiC).Represent volume element(RVE)models of microscale,void/matrix and mesoscale pr... Thermal conductivity is one of the most significant criterion of three-dimensional carbon fiber-reinforced SiC matrix composites(3D C/SiC).Represent volume element(RVE)models of microscale,void/matrix and mesoscale proposed in this work are used to simulate the thermal conductivity behaviors of the 3D C/SiC composites.An entirely new process is introduced to weave the preform with three-dimensional orthogonal architecture.The 3D steady-state analysis step is created for assessing the thermal conductivity behaviors of the composites by applying periodic temperature boundary conditions.Three RVE models of cuboid,hexagonal and fiber random distribution are respectively developed to comparatively study the influence of fiber package pattern on the thermal conductivities at the microscale.Besides,the effect of void morphology on the thermal conductivity of the matrix is analyzed by the void/matrix models.The prediction results at the mesoscale correspond closely to the experimental values.The effect of the porosities and fiber volume fractions on the thermal conductivities is also taken into consideration.The multi-scale models mentioned in this paper can be used to predict the thermal conductivity behaviors of other composites with complex structures. 展开更多
关键词 3D c/Sic composites Finite element analyses Multi-scale modeling Thermal conductivity
下载PDF
Designing Symmetric Gradient Honeycomb Structures with Carbon‑Coated Iron‑Based Composites for High‑Efficiency Microwave Absorption 被引量:1
4
作者 Yu Zhang Shu‑Hao Yang +9 位作者 Yue Xin Bo Cai Peng‑Fei Hu Hai‑Yang Dai Chen‑Ming Liang Yun‑Tong Meng Ji‑Hao Su Xiao‑Juan Zhang Min Lu Guang‑Sheng Wang 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第11期224-241,共18页
The impedance matching of absorbers is a vital factor affecting their microwave absorption(MA)properties.In this work,we controllably synthesized Material of Institute Lavoisier 88C(MIL-88C)with varying aspect ratios(... The impedance matching of absorbers is a vital factor affecting their microwave absorption(MA)properties.In this work,we controllably synthesized Material of Institute Lavoisier 88C(MIL-88C)with varying aspect ratios(AR)as a precursor by regulating oil bath conditions,followed by one-step thermal decomposition to obtain carbon-coated iron-based composites.Modifying the precursor MIL-88C(Fe)preparation conditions,such as the molar ratio between metal ions and organic ligands(M/O),oil bath temperature,and oil bath time,influenced the phases,graphitization degree,and AR of the derivatives,enabling low filler loading,achieving well-matched impedance,and ensuring outstanding MA properties.The MOF-derivatives 2(MD_(2))/polyvinylidene Difluoride(PVDF),MD_(3)/PVDF,and MD4/PVDF absorbers all exhibited excellent MA properties with optimal filler loadings below 20 wt%and as low as 5 wt%.The MD_(2)/PVDF(5 wt%)achieved a maximum effective absorption bandwidth(EAB)of 5.52 GHz(1.90 mm).The MD_(3)/PVDF(10 wt%)possessed a minimum reflection loss(RL_(min))value of−67.4 at 12.56 GHz(2.13 mm).A symmetric gradient honeycomb structure(SGHS)was constructed utilizing the high-frequency structure simulator(HFSS)to further extend the EAB,achieving an EAB of 14.6 GHz and a RL_(min) of−59.0 dB.This research offers a viable inspiration to creating structures or materials with high-efficiency MA properties. 展开更多
关键词 MIL-88c(Fe) Fe/Fe_(3)O_(4)/Fe_(3)c@c controllable preparation Symmetric gradient honeycomb structure Microwave absorbing
下载PDF
Ablation Processes for HfC-Coated 2.5D Needle-Punched Composites Used for Aerospace Engines Under Hypersonic Flight Conditions
5
作者 ZHANG Ziyi SHI Zhenyu +2 位作者 NI Jing WANG Jilai ZHANG Chengpeng 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2024年第5期645-655,共11页
The working environment of aerospace engines is extremely harsh with temperature exceeding 1700℃and accompanied by thermal coupling effects.In this condition,the materials employed in hypersonic aircraft undergo abla... The working environment of aerospace engines is extremely harsh with temperature exceeding 1700℃and accompanied by thermal coupling effects.In this condition,the materials employed in hypersonic aircraft undergo ablation issues,which can cause catastrophic accidents.Due to the excellent high-temperature stability and ablation resistance,HfC exhibits outstanding thermal expansion coefficient matching that of C/SiC composites.2.5D needle-punched C/SiC composites coated with HfC are prepared using a plasma spraying process,and a high-enthalpy arc-heated wind tunnel is employed to simulate the re-entry environment of aircraft at 8 Mach and an altitude of 32 km.The plasma-sprayed HfC-coated 2.5D needle-punched C/SiC composites are subjected to long-term dynamic testing,and their properties are investigated.Specifically,after the thermal assessment ablation experiment,the composite retains its overall structure and profile;the total mass ablation rate is 0.07445 g/s,the average linear ablation rate in the thickness direction is-0.0675μm/s,and the average linear ablation rate in the length direction is 13.907μm/s.Results verify that plasma-sprayed HfC coating exhibits excellent anti-oxidation and ablation resistance properties.Besides,the microstructure and ablation mechanism of the C/SiC composites are studied.It is believed that this work will offer guideline for the development of thermal protection materials and the assessment of structural thermal performance. 展开更多
关键词 2.5D needle-punched c/Sic composites ablation mechanism arc-heated wind tunnel experiment high enthalpy flow
下载PDF
Lignite-Based Hierarchical Porous C/SiO_(x)Composites as High-Performance Anode for Potassium-Ion Batteries
6
作者 Zexu Yang Shouwang Zhao +7 位作者 Rongji Jiao Gengyu Hao Yunying Liu Wenxiu He Jingwei Chen Guixiao Jia Jinlong Cui Shaohui Li 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2024年第4期107-117,共11页
Silicon oxide(SiO_(x),0<x≤2)has been recognized as a prominent anode material in lithium-ion batteries and sodium-ion batteries due to its high theoretical capacity,suitable electrochemical potential,and earth abu... Silicon oxide(SiO_(x),0<x≤2)has been recognized as a prominent anode material in lithium-ion batteries and sodium-ion batteries due to its high theoretical capacity,suitable electrochemical potential,and earth abundance.However,it is intrinsically poor electronic conductivity and excessive volume expansion during potassiation/depotassiation process hinder its application in potassium-ion batteries.Herein,we reported a hierarchical porous C/SiO_(x)potassium-ion batteries anode using lignite as raw material via a one-step carbonization and activation method.The amorphous C skeleton around SiO_(x)particles can effectively buffer the volume expansion,and improve the ionic/electronic conductivity and structural integrity,achieving outstanding rate capability and cyclability.As expected,the obtained C/SiO_(x)composite delivers a superb specific capacity of 370 mAh g^(-1)at 0.1 A g^(-1)after 100 cycles as well as a highly reversible capacity of 208 mAh g^(-1)after 1200 cycles at 1.0 A g^(-1).Moreover,the potassium ion storage mechanism of C/SiO_(x)electrodes was investigated by ex-situ X-ray diffraction and transmission electron microscopy,revealing the formation of reversible products of K_(6.8)Si_(45.3)and K_(4)SiO_(4),accompanied by generation of irreversible K2O after the first cycle.This work sheds light on designing low-cost Si-based anode materials for high-performance potassium-ion batteries and beyond. 展开更多
关键词 ANODE hierarchical porous c/SiO_(x) K_(4)SiO_(4) LIGNITE potassium-ion batteries
下载PDF
Compositional and Hollow Engineering of Silicon Carbide/Carbon Microspheres as High-Performance Microwave Absorbing Materials with Good Environmental Tolerance 被引量:2
7
作者 Lixue Gai Yahui Wang +5 位作者 Pan Wan Shuping Yu Yongzheng Chen Xijiang Han Ping Xu Yunchen Du 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第9期128-146,共19页
Microwave absorbing materials(MAMs)characterized by high absorption efficiency and good environmental tolerance are highly desirable in practical applications.Both silicon carbide and carbon are considered as stable M... Microwave absorbing materials(MAMs)characterized by high absorption efficiency and good environmental tolerance are highly desirable in practical applications.Both silicon carbide and carbon are considered as stable MAMs under some rigorous conditions,while their composites still fail to produce satisfactory microwave absorption performance regardless of the improvements as compared with the individuals.Herein,we have successfully implemented compositional and structural engineering to fabricate hollow Si C/C microspheres with controllable composition.The simultaneous modulation on dielectric properties and impedance matching can be easily achieved as the change in the composition of these composites.The formation of hollow structure not only favors lightweight feature,but also generates considerable contribution to microwave attenuation capacity.With the synergistic effect of composition and structure,the optimized SiC/C composite exhibits excellent performance,whose the strongest reflection loss intensity and broadest effective absorption reach-60.8 dB and 5.1 GHz,respectively,and its microwave absorption properties are actually superior to those of most SiC/C composites in previous studies.In addition,the stability tests of microwave absorption capacity after exposure to harsh conditions and Radar Cross Section simulation data demonstrate that hollow SiC/C microspheres from compositional and structural optimization have a bright prospect in practical applications. 展开更多
关键词 Sic/c composites compositional engineering Hollow engineering Microwave absorption Environmental tolerance
下载PDF
Experimental Investigation of the Anisotropic Thermal Conductivity of C/SiC Composite Thin Slab
8
作者 毋克凡 张虎 唐桂华 《Chinese Physics Letters》 SCIE EI CAS CSCD 2024年第3期48-60,共13页
Fiber-reinforced composites possess anisotropic mechanical and heat transfer properties due to their anisotropic fibers and structure distribution.In C/Si C composites,the out-of-plane thermal conductivity has mainly ... Fiber-reinforced composites possess anisotropic mechanical and heat transfer properties due to their anisotropic fibers and structure distribution.In C/Si C composites,the out-of-plane thermal conductivity has mainly been studied,whereas the in-plane thermal conductivity has received less attention due to their limited thickness. 展开更多
关键词 composites c/Si ANISOTROPIc
下载PDF
维生素C对禁食黄颡鱼抗氧化能力和肌肉品质的影响 被引量:2
9
作者 汪兰 夏雨婷 +9 位作者 胡澳 陈朗 郭晓嘉 乔宇 吴文锦 石柳 黄云 彭条凤 熊光权 陈胜 《广东海洋大学学报》 CAS CSCD 北大核心 2024年第1期20-26,共7页
【目的】研究添加不同浓度维生素C对禁食暂养黄颡鱼(Pelteobagrus fulvidraco)抗氧化能力和肌肉品质的影响,为提升鲜活黄颡鱼耐运性和肌肉品质提供理论依据。【方法】随机将黄颡鱼分为4组:T0-0(0 mg/L V_(C),暂养0 d)、T0-5(0 mg/L V_(... 【目的】研究添加不同浓度维生素C对禁食暂养黄颡鱼(Pelteobagrus fulvidraco)抗氧化能力和肌肉品质的影响,为提升鲜活黄颡鱼耐运性和肌肉品质提供理论依据。【方法】随机将黄颡鱼分为4组:T0-0(0 mg/L V_(C),暂养0 d)、T0-5(0 mg/L V_(C),暂养5 d)、T10-5(10 mg/L V_(C),暂养5 d)、T30-5(30 mg/L V_(C),暂养5 d),每组40尾鱼,检测血清、肌肉的抗氧化物质以及肌肉品质指标。【结果】T5-0组黄颡鱼血清中GSH-PX、CAT、GSH活性以及MDA浓度,肌肉中CAT、GSH活性和MDA浓度显著低于T1-0组(P<0.05);其纤维结构变得紧密,pH下降,白度增加,持水力增加,肌肉品质指标显著升高(P<0.05)。与T0-5及T30-5组相比,T10-5组血清中SOD、CAT、GSH、GSH-PX活性显著较高(P<0.05),MDA浓度较低;肌肉中SOD、GSH活性与血清中结果变化相同;持水力进一步增加。在质构方面,T10-5组剪切力、硬度、弹性、咀嚼性、黏性均高于T0-5组及T30-5组。【结论】添加10 mg/L的V_(C)能进一步显著提高黄颡鱼的抗氧化能力和肌肉品质(P<0.05),但30 mg/L V_(C)添加不利于黄颡鱼肌肉品质的提升,甚至对其产生负面影响。 展开更多
关键词 维生素c 黄颡鱼 暂养 运输应激 抗氧化能力 肌肉品质
下载PDF
Microwave absorption properties of Ni/C@SiC composites prepared by precursor impregnation and pyrolysis processes
10
作者 Xinli Ye Junxiong Zhang +4 位作者 Zhaofeng Chen Junfeng Xiang Yun Jiang Faqin Xie Xiaomin Ma 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第3期94-102,共9页
In the present study,the unique three-dimensional graphene coated nickel(Ni/C)foam reinforced silicon carbide(Ni/C@SiC)composites were first obtained via the precursor impregnation and pyrolysis(PIP)processes.The micr... In the present study,the unique three-dimensional graphene coated nickel(Ni/C)foam reinforced silicon carbide(Ni/C@SiC)composites were first obtained via the precursor impregnation and pyrolysis(PIP)processes.The microstructure images indicated that the SiC fillers were successfully prepared in the skeleton pores of the Ni/C foam.The influence of the PIP cycles on the microwave absorption performances was researched,and the results indicated that after the primary PIP process,Ni/C@SiC-I possessed the optimal microwave absorbing performance with a minimum reflection loss(RL)of-25.87 d B at 5.28 GHz and 5.00 mm.Besides,the RL values could be below-10.00 dB from 5.88 GHz to 7.74 GHz when the corresponding matching thickness was 3.85 mm.However,the microwave absorption properties of Ni/C@SiC-II and Ni/C@SiC-Ⅲwere tremendously degraded as the PIP times increased.At last,the electromagnetic parameter,dielectric loss,attenuation constant as well as impedance matching coefficient were further investigated to analyze the absorbing mechanism,which opened a new path for the certain scientific evaluation of the absorbing materials and had extremely important to the defence technology. 展开更多
关键词 composites Ni/c ABSORPTION
下载PDF
桂东北D/C界线沉积特征及对台盆相间演化的启示 被引量:1
11
作者 吴亮君 王璞珺 +11 位作者 吴继文 韦盛亮 户景松 吕勇 潘明 周嘉铭 林宇 廖家飞 韦伟 韦艾辰 李喜林 苏光样 《地质学报》 EI CAS CSCD 北大核心 2024年第4期1244-1262,共19页
台盆相间是桂东北泥盆纪和石炭纪沉积的重要特色,而D/C界线又是台盆相间沉积最突出的一个时段之一。文章回顾并评述了桂东北D/C界线的研究历程、相序划分、主要代表剖面,认为桂东北D/C界线可划分为碎屑岩相序和碳酸盐岩相序以及它们的... 台盆相间是桂东北泥盆纪和石炭纪沉积的重要特色,而D/C界线又是台盆相间沉积最突出的一个时段之一。文章回顾并评述了桂东北D/C界线的研究历程、相序划分、主要代表剖面,认为桂东北D/C界线可划分为碎屑岩相序和碳酸盐岩相序以及它们的过渡类型。通过对20条典型剖面的岩性组合特征对比,恢复了桂东北D/C界线海平面相对下降期的岩相古地理,结果显示桂东北在该时期主要存在柳州、桂林两大台地以及多个小型台地,台地间普遍发育快速相变的台沟、盆地沉积,石炭纪初期海水变浅,台地分布范围显著扩大,江南古陆供给增强,台盆相间格局迅速发展。为了进一步探讨桂东北D/C界线的演化过程和背后的控制因素,文章分析了广西整体的台盆相间演化的阶段性、同沉积构造作用以及海平面变化的影响,梳理了台盆相间演化过程中沉积环境分异与构造运动-海平面的关系,认为在滇黔桂裂谷盆地在持续断陷发展的前提下,桂东北D/C界线沉积分异的主要原因可能是受冈瓦纳大陆冰川形成与消融导致的海平面异常波动,以及柳江运动引发的局部同沉积断陷强度差异变动影响,且构造和沉积要素在D/C界线的耦合作用达到最强,最终促进桂东北台盆相间格局在D/C界线达到鼎盛。在此模式下,可以将台盆相间的演化划分为4个阶段,早泥盆世中期—晚期为台盆相间格局的孕育期,早泥盆世晚期—中泥盆世晚期沉积开始分异,为台盆相间格局的发展期,晩泥盆世—早石炭世台-盆出现强烈分割,海平面异常下降和柳江运动同时作用于沉积,为台盆相间格局的鼎盛期,早石炭世之后,台盆相间沉积维持了一定时期的强度,晚石炭世开始海水逐步恢复正常后台盆相间逐渐减弱,为台盆相间格局的衰退期。 展开更多
关键词 台盆相间 D/c界线 桂东北 广西 泥盆纪 石炭纪 古地理 柳江运动
下载PDF
莫来石-Ti(C,N)复合材料的制备及其力学性能研究 被引量:1
12
作者 陈博 董博 +7 位作者 邓承继 邹起良 丁军 朱万政 王前 张雍 祝洪喜 余超 《陶瓷学报》 CAS 北大核心 2024年第1期133-138,共6页
以TiO_(2)粉、石墨粉、Al/Si/Al_(2)O_(3)复合粉体为原料,在氮气气氛下经1400℃~1600℃保温2 h,采用碳热还原氮化法制备得到莫来石-Ti(C,N)复合材料,研究了烧成温度对复合材料物相组成、微观结构与力学性能的影响。结果表明:经1400℃热... 以TiO_(2)粉、石墨粉、Al/Si/Al_(2)O_(3)复合粉体为原料,在氮气气氛下经1400℃~1600℃保温2 h,采用碳热还原氮化法制备得到莫来石-Ti(C,N)复合材料,研究了烧成温度对复合材料物相组成、微观结构与力学性能的影响。结果表明:经1400℃热处理后,试样的物相组成为Ti(C,N)、SiO_(2)和硅线石。随热处理温度升高至1450℃~1600℃,硅线石消失的同时,试样出现了短柱状莫来石,并与无定形SiO_(2)紧密连接,形成有效的化学结合。当烧成温度为1500℃时,大量开口气孔随颗粒重排、界面移动而消失,材料颗粒间结合较为紧密,气孔数量明显减少,该烧成温度下试样具有最佳综合性能,其体积密度、弹性模量、抗折强度和维氏硬度分别为(3.48±0.02) g·cm-3、(138.5±0.1) GPa、(158.0±0.03) MPa和(21.01±0.01) GPa。 展开更多
关键词 TI(c N) 碳热还原氮化 莫来石 微观结构 力学性能
下载PDF
血清PCT、CRP及IL-4水平预测小儿支原体肺炎病情严重程度的价值 被引量:3
13
作者 王耀邦 沙宁 +1 位作者 杨娟 杨珊珊 《中外医学研究》 2024年第2期69-72,共4页
目的:探讨血清降钙素原(PCT)、C反应蛋白(CRP)及白细胞介素-4(IL-4)水平预测支原体肺炎患儿病情严重程度的价值。方法:选取2019年1月—2023年1月淮安市第二人民医院儿科收治的102例支原体肺炎患儿作为研究对象,根据病情将患儿分为轻症... 目的:探讨血清降钙素原(PCT)、C反应蛋白(CRP)及白细胞介素-4(IL-4)水平预测支原体肺炎患儿病情严重程度的价值。方法:选取2019年1月—2023年1月淮安市第二人民医院儿科收治的102例支原体肺炎患儿作为研究对象,根据病情将患儿分为轻症组59例和重症组43例。比较两组临床资料及基质细胞衍生因子(CXCL12)、γ干扰素(IFN-γ)、硫化氢(H_(2)S)、超氧化物歧化酶(SOD)、基质金属蛋白酶-9(MMP-9)、PCT、CRP及IL-4水平,多因素分析采取非条件logistic逐步回归分析,采用ROC曲线分析PCT、CRP及IL-4水平对重症支原体肺炎的预测价值。结果:两组性别、年龄、病程及CXCL12、IFN-γ、H_(2)S、SOD、MMP-9水平比较,差异无统计学意义(P>0.05);重症组PCT、CRP、IL-4水平显著高于轻症组,差异有统计学意义(P<0.05)。logistic逐步回归分析结果显示,PCT、CRP及IL-4为重症支原体肺炎独立危险因素(P<0.05)。ROC分析显示,PCT、CRP及IL-4预测重症支原体肺炎的曲线下面积分别为0.896、0.851、0.787。结论:血清PCT、CRP及IL-4水平均参与支气管肺炎患儿的病情进展,且可作为重症支气管肺炎的诊断指标。 展开更多
关键词 支原体肺炎 儿童 降钙素原 c反应蛋白 白细胞介素-4
下载PDF
嵌套加强的LQ550高强冷弯薄壁C型钢连续檩条受力性能研究 被引量:2
14
作者 袁焕鑫 房铭坤 +2 位作者 杜新喜 柯善夫 谭美超 《建筑结构》 北大核心 2024年第1期66-71,共6页
为提高LQ550级高强冷弯薄壁C型钢连续檩条的承载能力,采用在支座处嵌套的方法来加强连续檩条。对未加强和采用两种嵌套方式加强的檩条共7组试件进行三点受弯试验,得到了试件的承载性能和破坏形态,试验结果表明加强后的试件出现跨中局部... 为提高LQ550级高强冷弯薄壁C型钢连续檩条的承载能力,采用在支座处嵌套的方法来加强连续檩条。对未加强和采用两种嵌套方式加强的檩条共7组试件进行三点受弯试验,得到了试件的承载性能和破坏形态,试验结果表明加强后的试件出现跨中局部屈曲和嵌套端部局部屈曲两种破坏形态。采用ABAQUS软件建立了非线性有限元模型对嵌套加强的檩条进行数值模拟,有限元分析得到的承载力和破坏形态与试验结果吻合良好,验证了有限元模型的准确性。基于验证的有限元模型,分析了两种嵌套方式和不同嵌套长度对檩条承载力的提升,且表明嵌套檩条的长度宜取为连续檩条跨度的1/5~1/4。 展开更多
关键词 高强钢 冷弯薄壁c型钢 连续檩条 嵌套加强 受力性能
下载PDF
维生素C辅助阿奇霉素序贯疗法治疗儿童肺炎支原体肺炎的疗效 被引量:2
15
作者 何娜 郑光强 +3 位作者 黄娆 林科 陈耿浩 袁文霄 《川北医学院学报》 2024年第1期42-45,共4页
目的:探讨维生素C辅助阿奇霉素序贯疗法治疗儿童肺炎支原体肺炎(MPP)疗效及其对免疫功能的影响。方法:选取106例MPP患儿为研究对象,按照治疗方式不同分为观察组和对照组,每组各53例。观察组患者采用维生素C辅助阿奇霉素序贯疗法治疗;对... 目的:探讨维生素C辅助阿奇霉素序贯疗法治疗儿童肺炎支原体肺炎(MPP)疗效及其对免疫功能的影响。方法:选取106例MPP患儿为研究对象,按照治疗方式不同分为观察组和对照组,每组各53例。观察组患者采用维生素C辅助阿奇霉素序贯疗法治疗;对照组采用阿奇霉素治疗,疗程均为7 d。比较两组患儿临床疗效、症状缓解时间、肺功能、免疫功能及不良反应发生情况。结果:观察组患儿临床总有效率高于对照组(98.11%vs.86.79%,P<0.05)。治疗后,观察组患儿高热、咳嗽、肺啰音、胸片缓解时间短于对照组(P<0.05)。治疗前,两组患儿用力呼气肺活量占预计值百分比(FVC)、第1秒用力呼气肺活量(FEVl)、FEVl/FVC无统计学差异(P>0.05);治疗后,两组患儿FVC、FEVl、FEVl/FVC均升高,且观察组高于对照组(P<0.05)。治疗前,两组患儿外周血免疫球蛋白IgA、IgM、IgG水平无统计学差异(P>0.05);治疗后,两组患儿外周血IgA、IgG水平均升高,且观察组高于对照组(P<0.05);IgM水平均降低,且观察组低于对照组(P<0.05)。两组患儿治疗期间不良反应发生率比较,差异无统计学意义(P>0.05)。结论:阿奇霉素序贯疗法联合维生素C治疗儿童肺炎支原体肺炎能够提高疗效和免疫功能,值得临床推广。 展开更多
关键词 维生素c 阿奇霉素序贯疗法 肺炎支原体肺炎 免疫功能
下载PDF
大面积脑梗死患者血清Visfatin、TN-C、IL-17水平与神经功能缺损程度的相关性及对预后的预测价值 被引量:2
16
作者 李小磊 李华丽 石伟纲 《海南医学》 CAS 2024年第5期614-619,共6页
目的 探讨大面积脑梗死(LHI)患者血清内脂素(Visfatin)、肌腱蛋白C (TN-C)、白介素-17 (IL-17)水平与神经功能缺损程度的相关性及对患者预后的预测价值。方法 前瞻性选取2020年1月至2023年1月平顶山市第一人民医院收治的80例LHI患者作为... 目的 探讨大面积脑梗死(LHI)患者血清内脂素(Visfatin)、肌腱蛋白C (TN-C)、白介素-17 (IL-17)水平与神经功能缺损程度的相关性及对患者预后的预测价值。方法 前瞻性选取2020年1月至2023年1月平顶山市第一人民医院收治的80例LHI患者作为LHI组,另选取同期80例非大面积急性脑梗死(ACI)患者作为非LHI组,同期80例健康志愿者作为对照组。比较三组研究对象入院(体检)时的血清Visfatin、TN-C、IL-17水平,并比较LHI组不同神经功能缺损程度患者的血清Visfatin、TN-C、IL-17水平,采用Spearman相关系数分析血清Visfatin、TN-C、IL-17水平与LHI神经功能缺损程度的相关性。比较LHI组不同预后患者入院时血清Visfatin、TN-C、IL-17水平,通过受试者工作特征曲线(ROC)分析血清Visfatin、TN-C、IL-17水平预测预后的价值,采用KM生存曲线分析不同血清Visfatin、TN-C、IL-17水平患者3个月存活情况。结果 LHI组患者入院时的血清Visfatin、TN-C、IL-17水平分别为(86.74±25.17)μg/L、(81.45±20.67)μg/L、(118.19±28.26) pg/mL,明显高于非LHI组的(51.63±16.24)μg/L、(61.29±15.16)μg/L、(76.70±15.49) pg/mL和对照组的(7.71±1.59)μg/L、(19.61±7.38)μg/L、(29.51±6.02) pg/mL,且非LHI组患者的血清Visfatin、TN-C、IL-17水平明显高于对照组,差异均具有统计学意义(P<0.05);LHI组神经功能缺损程度重度患者入院时的血清Visfatin、TN-C、IL-17水平分别为(98.71±18.25)μg/L、(95.38±16.84)μg/L、(135.71±26.03) pg/mL,明显高于中度患者的(79.17±15.61)μg/L、(72.64±14.10)μg/L、(107.11±22.49) pg/mL,差异均具有统计学意义(P<0.05);经Spearman相关分析法分析结果显示,入院时血清Visfatin、TN-C、IL-17水平与LHI患者神经功能缺损程度呈正相关(P<0.05);LHI组预后不良患者入院时的血清Visfatin、TN-C、IL-17水平分别为(101.25±19.17)μg/L、(98.74±17.43)μg/L、(140.71±28.01) pg/mL,明显高于预后良好患者的(78.49±16.20)μg/L、(71.62±15.76)μg/L、(105.38±24.26) pg/mL,差异均有统计学意义(P<0.05);经ROC分析结果显示,入院时血清Visfatin、TN-C、IL-17水平联合预测LHI预后不良的曲线下面积(AUC)为0.951 (95%CI:0.878~0.987),大于三项指标单独预测的AUC (P<0.05);LHI组入院时血清Visfatin、TN-C、IL-17高水平患者3个月后存活率分别为74.29%、76.32%、70.97%,明显低于血清Visfatin、TN-C、IL-17低水平患者的93.33%、92.86%、93.88%,差异均有统计学意义(P<0.05)。结论 LHI患者血清Visfatin、TN-C、IL-17水平明显升高,且与神经功能缺损程度呈正相关,联合检测各指标可为临床预测患者预后提供可靠依据。 展开更多
关键词 大面积脑梗死 内脂素 肌腱蛋白c 白介素-17 神经功能缺损 预后
下载PDF
Lp-PLA2、hs-CRP和FIB联合检测在急性脑梗死诊断中的应用 被引量:3
17
作者 孟凤琴 曹军 +2 位作者 石亚志 李战永 于奇 《标记免疫分析与临床》 CAS 2024年第2期287-291,共5页
目的探讨血浆脂蛋白相关磷脂酶A2(Lp-PLA2)、超敏C反应蛋白(hs-CRP)和纤维蛋白原(FIB)联合检测在急性脑梗死诊断中的临床价值。方法收集我院240例急性脑梗死的住院患者作为研究对象(脑梗组),以100例门诊体检健康人员为对照组,比较两组... 目的探讨血浆脂蛋白相关磷脂酶A2(Lp-PLA2)、超敏C反应蛋白(hs-CRP)和纤维蛋白原(FIB)联合检测在急性脑梗死诊断中的临床价值。方法收集我院240例急性脑梗死的住院患者作为研究对象(脑梗组),以100例门诊体检健康人员为对照组,比较两组人群的一般临床数据及检验结果,记录患者入院时的NIHSS评分。分析急性脑梗死患者血浆Lp-PLA2、hs-CRP和FIB水平与其神经功能缺损程度的关系,进行多因素Logistic回归分析确定急性脑梗死的危险因素,利用ROC曲线评估患者血浆Lp-PLA2、hs-CRP和FIB水平对急性脑梗死的诊断价值。结果重度脑梗死患者的Lp-PLA2、hs-CRP和FIB水平均高于轻度及中度脑梗死患者(P<0.05);与对照组比较,脑梗组患者的血浆Lp-PLA2、hs-CRP和FIB水平均显著升高,差异均具有统计学意义(P<0.05)。血浆Lp-PLA2、hs-CRP和FIB水平与急性脑梗死发病风险显著相关(P<0.05)。Lp-PLA2、hs-CRP和FIB 3个指标中,Lp-PLA2的ROC曲线下面积最大,诊断价值最高;Lp-PLA2、hs-CRP和FIB联合检测能显著提高急性脑梗死的诊断效率。结论联合检测Lp-PLA2、hs-CRP和FIB对判断ACI患者神经功能缺损程度具有较高价值。 展开更多
关键词 急性脑梗死 脂蛋白相关磷脂酶A2 超敏c反应蛋白 纤维蛋白原
下载PDF
参松养心胶囊联合沙库巴曲缬沙坦治疗阵发性心房颤动合并慢性心力衰竭对hs-CRP、BNP、AngⅡ及心功能的影响 被引量:4
18
作者 何文凤 薛成 +2 位作者 郑健康 帅壮 岳荣川 《中华中医药学刊》 CAS 北大核心 2024年第6期95-98,共4页
目的 探讨参松养心胶囊联合沙库巴曲缬沙坦治疗阵发性心房颤动合并慢性心力衰竭对高敏C反应蛋白(High sensitivity C-reactive protein, hs-CRP)、脑钠肽(Brain natriuretic peptide, BNP)、血管紧张素Ⅱ(AngiotensinⅡ,AngⅡ)及心功能... 目的 探讨参松养心胶囊联合沙库巴曲缬沙坦治疗阵发性心房颤动合并慢性心力衰竭对高敏C反应蛋白(High sensitivity C-reactive protein, hs-CRP)、脑钠肽(Brain natriuretic peptide, BNP)、血管紧张素Ⅱ(AngiotensinⅡ,AngⅡ)及心功能的影响。方法 选取100例阵发性心房颤动合并慢性心力衰竭患者,随机分为对照组与观察组,每组50例,对照组在常规治疗基础上给予沙库巴曲缬沙坦口服,观察组在常规治疗基础上给予参松养心胶囊联合沙库巴曲缬沙坦口服治疗,疗程6个月。观察血清hs-CRP、BNP、AngⅡ、左心室射血分数(Left ventricular ejection fraction, LVEF)、左室收缩末期内径(Left ventricular end systolic diameter, LVESD)、左室舒张末期内径(Left ventricular end diastolic diameter, LVEDD)变化。结果 两组治疗前血清hs-CRP、BNP、AngⅡ比较差异无统计学意义(P>0.05),治疗后下降(P<0.05),且观察组低于对照组(P<0.05);两组治疗前LVEF、LVESD、LVEDD比较差异无统计学意义(P>0.05),治疗后LVEF升高(P<0.05),且观察组高于对照组(P<0.05),治疗后LVESD、LVEDD下降(P<0.05),且观察组低于对照组(P<0.05);两组治疗前阵发性心房颤动发作次数、阵发性心房颤动持续时间、心室率比较差异无统计学意义(P>0.05),治疗后下降(P<0.05),且观察组低于对照组(P<0.05);对照组转为持续性心房颤动、心力衰竭恶化、缺血心源性死亡率分别为20.00%、22.00%、4.00%,观察组分别为4.00%、6.00%、0.00%,转为持续性心房颤动、心力衰竭恶化发生率对照组高于观察组(P<0.05);观察组治疗疗效优于对照组(P<0.05)。结论 参松养心胶囊联合沙库巴曲缬沙坦治疗阵发性心房颤动合并慢性心力衰竭有助于促进hs-CRP、BNP、AngⅡ下降,改善患者心功能,改善预后。 展开更多
关键词 参松养心胶囊 沙库巴曲缬沙坦 阵发性心房颤动 慢性心力衰竭 高敏c反应蛋白 脑钠肽 血管紧张素Ⅱ 心功能
下载PDF
通督调神针法治疗阴虚动风型脑梗死偏瘫疗效及对患者血清Hcy、CRP水平的影响 被引量:1
19
作者 齐涛 张闻东 +1 位作者 李佩芳 刘辉 《陕西中医》 CAS 2024年第5期696-699,共4页
目的:探讨通督调神针法治疗阴虚动风型脑梗死偏瘫患者疗效及对患者血清同型半胱氨酸(Hcy)、C反应蛋白(CRP)水平的影响。方法:选取脑梗死偏瘫患者76例,1∶1随机分为观察组(西医治疗+通督调神针法)与对照组(常规西医治疗)各38例。持续治疗... 目的:探讨通督调神针法治疗阴虚动风型脑梗死偏瘫患者疗效及对患者血清同型半胱氨酸(Hcy)、C反应蛋白(CRP)水平的影响。方法:选取脑梗死偏瘫患者76例,1∶1随机分为观察组(西医治疗+通督调神针法)与对照组(常规西医治疗)各38例。持续治疗1个月后,评估两组临床疗效,比较两组治疗前后中医证候积分、血清炎症因子(Hcy、CRP)水平、运动功能[Fugl-Meyer评定量表(FMA)]、平衡功能[Berg平衡量表(BBS)]和移动功能[功能性步态评价表(FGA)]变化情况,并记录两组不良事件发生率。结果:观察组总有效率更高(P<0.05);观察组治疗后中医证候积分降低程度比对照组更明显(P<0.05)。观察组治疗后FMA、FGA和BBS评分升高水平均比对照组更明显(P<0.05),观察组治疗后Hcy、CRP水平下降程度均比对照组更明显(P<0.05)。治疗期间两组均无不良事件发生。结论:阴虚动风型脑梗死偏瘫患者应用通督调神针法联合常规西医治疗具有较好的增益效果,可有效提高临床疗效,缓解患者临床症状,提高运动、平衡和移动能力,降低炎症反应。 展开更多
关键词 脑梗死偏瘫 通督调神针法 阴虚动风型 血清同型半胱氨酸 c反应蛋白 运动功能
下载PDF
龟羚帕安丸对帕金森病大鼠血清NSE、Cys-C、5-HT、5-HIAA及NE水平的影响 被引量:2
20
作者 常学辉 陈帅杰 +2 位作者 张良芝 王冬莲 张创业 《中华中医药学刊》 CAS 北大核心 2024年第2期1-4,共4页
目的观察龟羚帕安丸对帕金森病(Parkinson’s disease,PD)大鼠血清神经元特异性烯醇化酶(Neuron-specific enolase,NSE)、胱抑素C(Cystatin C,Cys-C)、5-羟色胺(5-Hydroxytryptamine,5-HT)、5-羟基吲哚乙酸(5-Hydroxyindoleacetic acid,... 目的观察龟羚帕安丸对帕金森病(Parkinson’s disease,PD)大鼠血清神经元特异性烯醇化酶(Neuron-specific enolase,NSE)、胱抑素C(Cystatin C,Cys-C)、5-羟色胺(5-Hydroxytryptamine,5-HT)、5-羟基吲哚乙酸(5-Hydroxyindoleacetic acid,5-HIAA)及去甲肾上腺素(Norepinephrine,NE)水平的影响。方法采用6-羟基多巴胺(6-OHDA)立体定向注射法制作PD大鼠模型,造模成功的PD大鼠随机分为模型组,西药组,中药高、中、低剂量组,中西药合用组,每组15只,另设假手术组15只。模型组及假手术组给予等容积生理盐水灌胃,其余组给予相应药物灌胃,连续给药28 d。大鼠腹主动脉取血,用酶联免疫吸附测定法(Enzyme linked immunosorbent assay,ELISA)检测各组大鼠血清NSE、Cys-C、5-HT、5-HIAA及NE的水平。结果模型组大鼠血清NSE及Cys-C水平均明显升高,血清5-HT、5-HIAA及NE水平均明显降低;中药各剂量组、中西药合用组、西药组血清NSE及Cys-C水平均明显降低,5-HT、5-HIAA及NE水平均明显升高。结论龟羚帕安丸具有明显神经保护作用,作用机制与降低NSE及Cys-C水平,增加5-HT、5-HIAA及NE水平,降低脑实质损伤、神经炎症损伤及提高单胺类神经递质有关。 展开更多
关键词 帕金森病 龟羚帕安丸 神经元特异性烯醇化酶 胱抑素c 5-羟色胺 5-羟基吲哚乙酸
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部