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Three-Dimensional Simulations of RESET Operation in Phase-Change Random Access Memory with Blade-Type Like Phase Change Layer by Finite Element Modeling 被引量:2
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作者 金秋雪 刘波 +8 位作者 刘燕 王维维 汪恒 许震 高丹 王青 夏洋洋 宋志棠 封松林 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第9期128-131,共4页
An optimized device structure for reducing the RESET current of phase-change random access memory (PCRAM) with blade-type like (BTL) phase change layer is proposed. The electrical thermal analysis of the BTL cell ... An optimized device structure for reducing the RESET current of phase-change random access memory (PCRAM) with blade-type like (BTL) phase change layer is proposed. The electrical thermal analysis of the BTL cell and the blade heater contactor structure by three-dimensional finite element modeling are compared with each other during RESET operation. The simulation results show that the programming region of the phase change layer in the BTL cell is much smaller, and thermal electrical distributions of the BTL cell are more concentrated on the TiN/GST interface. The results indicate that the BTL cell has the superiorities of increasing the heating efficiency, decreasing the power consumption and reducing the RESET current from 0.67mA to 0.32mA. Therefore, the BTL cell will be appropriate for high performance PCRAM device with lower power consumption and lower RESET current. 展开更多
关键词 PCRAM cell RESET Three-Dimensional Simulations of RESET Operation in phase-Change Random Access Memory with Blade-Type Like phase Change layer by Finite Element Modeling of by in with
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The Effect of Varied Dietary Crude Protein Levels with Balanced Amino Acids on Performance and Egg Quality Characteristics of Layers at First Laying Phase 被引量:3
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作者 Gbemiga Oladimeji Adeyemo Sulaiman Adewole Abioye Foluke A. Aderemi 《Food and Nutrition Sciences》 2012年第4期526-529,共4页
Four diets were formulated to study the influence of varying crude protein levels on the performance, egg quality, serum and haematological characteristics at the first phase of laying cycle of sixty Bovan Nera laying... Four diets were formulated to study the influence of varying crude protein levels on the performance, egg quality, serum and haematological characteristics at the first phase of laying cycle of sixty Bovan Nera laying birds that were randomly allotted to dietary treatments. The four experimental diets had five replicates each and three birds per repli-cate. Diet 1 contained 14% crude protein (CP), while diet 2 contained 15% CP, diets 3 and 4 contained 16% and 17% CP respectively. The experimental birds were fed for 10 weeks and the data collected were statistically analysed. Apparent variations recorded for all the performance characteristics such as Egg number, Hen-day production, Feed Conversion Ratio (FCR) and weight gain were significantly different (p < 0.05). The best FCR value were recorded by birds fed 17% CP (3.45), while the highest weight gain mean value were also recorded by birds fed 17% CP value. Findings indicated a direct relationship between dietary crude protein values and performance. 展开更多
关键词 EGG Quality FIRST LAYING phase layerS PERFORMANCE and Varied Crude Protein Levels
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Comparison of liquid-liquid extraction-thin layer chromatography with solid-phase extraction-high-performance thin layer chromatography in detection of urinary morphine 被引量:1
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作者 Ali Ahadi Alireza Partoazar +1 位作者 Mohammad Hassan Abedi Khorasgani Seyed Vahid Shetab Boushehri 《The Journal of Biomedical Research》 CAS 2011年第5期362-367,共6页
Liquid-liquid extraction-thin layer chromatography (LLE-TLC) has been a common and routine combined method for detection of drugs in biological materials. Solid-phase extraction (SPE) is gradually replacing the tr... Liquid-liquid extraction-thin layer chromatography (LLE-TLC) has been a common and routine combined method for detection of drugs in biological materials. Solid-phase extraction (SPE) is gradually replacing the tra- ditional LLE method. High performance thin layer chromatography (HPTLC) has several advantages over TLC. The present work studied the higher efficiency of a new SPE-HPTLC method over that of a routine LLE-TLC method, in extraction and detection of urinary morphine. Fifty-eight urine samples, primarily identified as mor- phine-positive samples by a strip test, 'were re-screened by LLE-TLC and SPE-HPTLC. The results of LLE-TLC and SPE-HPTLC were then compared with each other. The results showed that the SPE-HPTLC detected 74% of total samples as morphine-positive samples whereas the LLE-TLC detected 48% of the same samples. We further discussed the effect of codeine abuse on TLC analysis of urinary morphine. Regarding the importance of morphine detection in urine, the present combined SPE-HPTLC method is suggested as a replacement method for detection of urinary morphine by many reference laboratories. 展开更多
关键词 morphine detection liquid-liquid extraction thin-layer chromatography solid-phase extraction highperformance thin layer chromatography
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Properties of Phase Transformation of Ferroelectric Thin Films with Surface Layers
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作者 Lian Cui Xu Xu +3 位作者 JiXin Che Zelong He Huijie Xue Tianquan Lv 《Journal of Modern Physics》 2011年第9期1037-1040,共4页
Using the generalized Ginzburg-Landau-Devonshire theory, the characteristics of phase transformation of a ferroelectric thin film with surface layers are investigated. We study the effect of the surface layer on the p... Using the generalized Ginzburg-Landau-Devonshire theory, the characteristics of phase transformation of a ferroelectric thin film with surface layers are investigated. We study the effect of the surface layer on the properties (coercive field, critical thickness) of a ferroelectric thin film. Our theoretical results show that the surface layer is likely to answer for the emergence of phase transformation. 展开更多
关键词 FERROELECTRIC THIN FILM Surface layer phase TRANSFORMATION
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STUDY ON DETERMINATION OF TRACE Cu(Ⅱ) BY DDCT CHELATING RESIN PRECONCENTRATION AND THIN LAYER RESIN PHASE SPECTROPHOTOMETRY
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作者 LI Chunxiang YAN Yongsheng +1 位作者 SONG Huanyu WANG Yun 《Chinese Journal of Reactive Polymers》 2006年第2期161-166,共6页
A new method for determination of Cu(Ⅱ) by DDCT chelating resin preconcentration and thin layer resin phase spectrophotometry was developed. The method has a high sensitivity (ε455= 3.6×10^5L/mol·cm), ... A new method for determination of Cu(Ⅱ) by DDCT chelating resin preconcentration and thin layer resin phase spectrophotometry was developed. The method has a high sensitivity (ε455= 3.6×10^5L/mol·cm), which is 33 times higher than that of liquid phase spectrophotometry. It has a good selectivity (most coexisting ions could not influence determination) and an ideal precision [30μg Cu(Ⅱ), n=6, RSD= l.67%]. The content of Cu(Ⅱ) in water, high purity rare earth and its oxide was determined. The detection limit of Cu(Ⅱ) is 5.3μg/L , and the linear range is 0-7.2μg/ml. The result is satisfactory. 展开更多
关键词 Chelating resin PRECONCENTRATION Thin layer resin phase spectrophotometry TRACE Cu(Ⅱ)
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STUDY ON DETERMINATION OF TRACE Fe BY Fe(Ⅱ)-VA THIN LAYER RESIN PHASE SPECTROPHOTOMETRY
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作者 SONG Huanyu YAN Yongsheng WANG Yun 《Chinese Journal of Reactive Polymers》 2006年第2期155-160,共6页
A new method for the determination of Fe by thin layer resin phase spectrophotometry in alkali condition was reported. The complex anion formed by Fe(Ⅱ) and VA was absorbed on the 717w resin and Fe was determined b... A new method for the determination of Fe by thin layer resin phase spectrophotometry in alkali condition was reported. The complex anion formed by Fe(Ⅱ) and VA was absorbed on the 717w resin and Fe was determined by making thin layer. This method had a high sensitivity (ε620= 3.0×10^5L/mol.cm), which was 15 times higher than that of liquid phase spectrophotometry. It had been proved a satisfactory precision (5.01μg Fe, n=6, RSD=1.8%). The trace Fe in natural water was determined and the recovery was 97%. 展开更多
关键词 Thin layer resin phase spectrophotometry TRACE FE
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STUDY ON THE DETERMINATION OF TRACE Fe(Ⅲ) BY THIN LAYER RESIN PHASE SPECTROPHOTOMETRY
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作者 HOU Yanmin YANG Yongsheng +1 位作者 XIE Jimin HUANG Weihong 《Chinese Journal of Reactive Polymers》 2007年第1期80-84,共5页
A method to determine Fe(Ⅲ) by thin layer resin phase spectrophotometry has been developed in this paper. The colored complex formed by Fe(Ⅲ) and 1,2-benzendiol is concentrated on the 717^# resin, then Fe(Ⅲ) ... A method to determine Fe(Ⅲ) by thin layer resin phase spectrophotometry has been developed in this paper. The colored complex formed by Fe(Ⅲ) and 1,2-benzendiol is concentrated on the 717^# resin, then Fe(Ⅲ) can be determined directly by making thin layer. The method is sensitive with a apparent molar absorption of 4.8×10^4L/mol.cm, which is 16 times higher than that of liquid phase spectrophotornetry, most coexisting ions do not influence the determination. The detection limit for Fe(Ⅲ) is 1.47μg/L with the precision of 3.3% [n=6, 7μg/50mL Fe(Ⅲ)]. The calibration curve is linear in the range of 0-25μg/50mL. The preposed method was applied to the determination of Fe(Ⅲ) in water sample with satisfactory results. 展开更多
关键词 1 2-benzendiol Thin layer resin phase spectrophotometry Fe(Ⅲ).
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Tuning the phase separation in La_(0.325)Pr_(0.3)Ca_(0.375)MnO_3 using the electric double-layer field effect
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作者 崔丽敏 李洁 +5 位作者 张玉 赵璐 邓辉 黄克强 李贺康 郑东宁 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第9期528-534,共7页
Electric double-layer field effect experiments were performed on ultrathin films of La0.325Pr0.3Ca0.375MnO3, which is noted for its micrometer-scale phase separation. A clear change of resistance up to 220% was observ... Electric double-layer field effect experiments were performed on ultrathin films of La0.325Pr0.3Ca0.375MnO3, which is noted for its micrometer-scale phase separation. A clear change of resistance up to 220% was observed and the characteristic metal-insulator transition temperature Tp was also shifted. The changes of both the resistance and Tp, suggest that the electric field induced not only tuning of the carrier density but also rebalancing of the phase separation states. The change of the charge-ordered insulating phase fraction was estimated to be temperature dependent, and a maximum of 16% was achieved in the phase separation regime. This tuning effect was partially irreversible, which might be due to an oxygen vacancy migration that is driven by the huge applied electric field. 展开更多
关键词 electric double-layer field effect MANGANITES phase separation
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AN IMPLICIT ALGORITHM OF THIN LAYER EQUATIONS IN VISCOUS,TRANSONIC,TWO-PHASE NOZZLE FLOW
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作者 何洪庆 侯晓 +1 位作者 蔡体敏 吴心平 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1994年第4期323-334,共12页
Omitting viscosity along flow direction, we have simplified the dimensionless N-Sequations in arbitrary curved coordinate system as the thin layer equations. Using theimplicit approximate-factorization algorithm to so... Omitting viscosity along flow direction, we have simplified the dimensionless N-Sequations in arbitrary curved coordinate system as the thin layer equations. Using theimplicit approximate-factorization algorithm to solve the gas-phase governing equ-ations and the characteristic method to follow the tracks of particles, we then obtainedthe full coupled numerical method of two-phase.transonic, turbulent flow. Here, par- ticle size may be grouped, the subsonic boundary condition at entry of nozzle is ireatedby quasi-characteristic method in reference plane and the algebraic model is used forturbulent flow. These methods are applied in viscous two-phase flow. calculation of ro-cket nozzle and in the prediciton of thrust and specific impulse for solid propellant ro-cket motor. The calculation results are in good agreement with the measurerment va-lues. Moreover, the influences of different particle radius, different particle mass frac-tion and particle size grouped on flow field have been discussed, and the influences of particle two-dimensional radial velosity component and viscosity on specific impulse ofrocket motor have been analysed.The method of this paper possesses the advantage of saving computer time. More important, the effect is more obvious for the calculation of particle size being grouped. 展开更多
关键词 thin layer equations two-phase viscous transonic nozzle flow implicit algorithm
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Effect of Phase Change Materials on the Thermal Protective Performance of the Multi-layered Fabrics Examined by TPP Tester under Flash Fire 被引量:1
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作者 赵蒙蒙 李俊 《Journal of Donghua University(English Edition)》 EI CAS 2016年第1期150-154,共5页
Cotton fabrics treated with phase change materials( PCMs)were used in multi-layered fabrics of the fire fighter protective clothing to study its effect on thermal protection. The thermal protective performance( TPP) o... Cotton fabrics treated with phase change materials( PCMs)were used in multi-layered fabrics of the fire fighter protective clothing to study its effect on thermal protection. The thermal protective performance( TPP) of the multi-layered fabrics was measured by a TPP tester under flash fire. Results showed that the utilization of the PCM fabrics improved the thermal protective performance of the multi-layered fabrics. The fabric with a PCM add on of 41. 9% increased the thermal protection by 50. 6% and reduced the time to reach a second degree burn by 8. 4 s compared with the reference fabrics( without PCMs). The employment of the PCM fabrics also reduced the blackened areas on the inner layers. The PCM fabrics with higher PCM melting temperature could bring higher thermal protective performance. 展开更多
关键词 phase change material(PCM) multi-layered fabrics thermal protection performance(TPP) fire fighter protective clothing
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Comparison of Isobaric and Non-isobaric Operations on a Two-Phase Dynamic Model for PEFC Cathode Gas Diffusion Layer
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作者 纪光霁 陈翌 +1 位作者 周苏 陈凤祥 《Journal of Donghua University(English Edition)》 EI CAS 2011年第6期539-546,共8页
Key words,: Two 1-D dynamical and isothermal models of cathode gas diffusion layer(GDL) with isobaric and non-isobaric operations for polymer electrolyte fuel cells(PEFCs) were developed and implemented in COMSOL... Key words,: Two 1-D dynamical and isothermal models of cathode gas diffusion layer(GDL) with isobaric and non-isobaric operations for polymer electrolyte fuel cells(PEFCs) were developed and implemented in COMSOL Multiphysics v3.5.The artificial diffusion coefficient was introduced as well to make the numerical computation be stable.In the non-isobaric model,the pressure of gas mixture was obtained by summing up the governing equations of gaseous components,instead of Navier-Stoks equation.Comparison of the two models were carried out with the steady-states and dynamical simulations under given conditions.The corresponding analysis based on the simulated results was also given simultaneously.This paper is contributed to finding the differences between the isobaric and non-isobaric operation in the two-phase model of cathode GDL. 展开更多
关键词 TWO-phase model gas diffusion layer(GDL) ISOBARIC and non-isobaric operations polymer electrolyte fuel cell(PEFC)
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一种增强相控阵天线性能的介质层设计方法
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作者 张明月 许广钰 +2 位作者 刘志惠 刘兆松 高仁璟 《计算力学学报》 北大核心 2026年第1期33-39,共7页
堆叠介质层是实现相控阵天线宽带宽角扫描的常用方法,但传统PCB材料性质(介质特性和厚度等)常面临无法满足实现天线性能所需的材料特性的问题,进而限制了天线的性能提升空间。针对这一问题,本文提出一种考虑3D打印精度的介质层设计方法... 堆叠介质层是实现相控阵天线宽带宽角扫描的常用方法,但传统PCB材料性质(介质特性和厚度等)常面临无法满足实现天线性能所需的材料特性的问题,进而限制了天线的性能提升空间。针对这一问题,本文提出一种考虑3D打印精度的介质层设计方法,以改善相控阵天线的阻抗匹配特性。该方法首先通过优化算法确定最优的介质层尺寸和介电参数,然后基于散射参数反演法设计具有上述特征的材料单胞,用于构建所需的介质层。为保证设计的介质层的可制造性,将3D打印精度作为材料单胞的尺寸约束。基于该方法,设计了由馈电区、辐射区和匹配区组成的工作在X波段的相控阵天线单元,通过设计介质层微结构实现介质层减重47.89%;从仿真结果看,设计的天线可以在X波段实现法向驻波比小于2,在E平面和H平面实现±60°扫描时驻波比均小于2.5,并且具有良好的极化纯度。 展开更多
关键词 散射参数反演法 3D打印 堆叠介质层 相控阵天线 宽带宽角扫描
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马氏体耐热钢/镍基合金异种金属界面过渡层设计
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作者 高健飞 付佳 +4 位作者 夏美玲 穆浪 于云鹤 侯纪新 夏志新 《精密成形工程》 北大核心 2026年第2期60-72,共13页
目的 针对超超临界火电领域对马氏体耐热钢/镍基合金高质量结合的需求,设计过渡层成分,并探究合金体系及元素扩散对组织与性能的影响。方法 综合考虑耐高温与抗腐蚀性能,并结合熵焓比-原子半径差(Ω-δ)、混合焓(∆H_(mix))和电子浓度(VEC... 目的 针对超超临界火电领域对马氏体耐热钢/镍基合金高质量结合的需求,设计过渡层成分,并探究合金体系及元素扩散对组织与性能的影响。方法 综合考虑耐高温与抗腐蚀性能,并结合熵焓比-原子半径差(Ω-δ)、混合焓(∆H_(mix))和电子浓度(VEC)等固溶体判据,初步筛选出FeNiCr中熵合金过渡层体系。利用JMat Pro软件模拟Fe、Ni、Cr元素扩散对G115马氏体耐热钢与617B镍基合金相平衡、物理性能及力学性能的影响。结果 计算结果表明,FeNiCr合金易形成面心立方结构简单固溶体。Cr元素扩散使G115钢中M_(6)C相消失,当Cr的质量分数达到9%时,会诱发σ相;Fe元素扩散促使617B合金形成MC相,而Cr扩散使M_(6)C相消失并出现MC相。Ni元素扩散显著影响G115钢的线膨胀系数与力学性能,Fe元素扩散导致617B合金力学性能下降,而Cr元素扩散可提升617B合金的力学性能。结论 Fe NiCr合金过渡层可对Fe、Ni元素无限固溶,有助于实现界面成分梯度平缓过渡,通过控制元素扩散可形成物理性能梯度分布、提升力学性能,为马氏体耐热钢/镍基合金异种金属连接界面设计与性能优化提供了重要的理论参考。 展开更多
关键词 异种金属 过渡层 固溶体 相平衡 元素扩散
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基于相位调制自发辐射光的微波光子隐蔽通信技术
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作者 刘占琪 朱华涛 +7 位作者 姜丰 刘一伯 张鑫 徐向明 杨晨昊 丁海洋 赵永利 张杰 《移动通信》 2026年第1期59-67,共9页
放大自发辐射(ASE)光是光隐蔽通信的理想光源,其具有与光噪声相同的信号特征,相位调制不会改变ASE光的时频域特性。然而,由于ASE光的相干长度仅为亚毫米级,基于延迟线干涉仪的解调器无法适用。基于此,提出了一种用于相位调制ASE光的新... 放大自发辐射(ASE)光是光隐蔽通信的理想光源,其具有与光噪声相同的信号特征,相位调制不会改变ASE光的时频域特性。然而,由于ASE光的相干长度仅为亚毫米级,基于延迟线干涉仪的解调器无法适用。基于此,提出了一种用于相位调制ASE光的新型微波光子滤波检测方法,相位调制后的ASE光在光域内通过25 km的公共光信道实现隐蔽传输。为验证电域微波光子隐蔽通信的可行性,加入了可重构智能表面用于反射光电探测器输出的电信号。通过阐述微波光子隐蔽通信原理,对原理验证实验装置进行介绍,给出了实验结果与讨论,并得出结论,该方案将拓展微波光子学在隐蔽通信及6G安全通信的应用。 展开更多
关键词 6G 隐蔽通信 物理层安全 光通信 相位调制
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自分层储能电池体系的研究进展
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作者 杜心怡 王雨晨 +3 位作者 崔洋洋 王路宽 李奇 王存国 《化工科技》 2026年第1期47-52,共6页
自分层电池凭借其无膜结构设计和独特的自发相分离机制,被认为是电网储能领域极具前景的候选方案之一。该电池通过液体组分间的密度和极性差异实现自发相分层,构建稳定的液-液界面,有效解决了传统电池中隔膜成本高和电极稳定性差等问题... 自分层电池凭借其无膜结构设计和独特的自发相分离机制,被认为是电网储能领域极具前景的候选方案之一。该电池通过液体组分间的密度和极性差异实现自发相分层,构建稳定的液-液界面,有效解决了传统电池中隔膜成本高和电极稳定性差等问题。详细阐述了自分层储能电池的基本工作原理,介绍了液态金属自分层电池、水性双相自分层电池、水-有机双相自分层电池、非水双相自分层电池等研究进展,为新型自分层电池的构建与应用提供借鉴。 展开更多
关键词 自分层电池 液态金属 二次电池 相分离 有机电解质
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钠离子电池P2/O3相正极材料改性研究进展
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作者 李添 段其乐 +1 位作者 赵德威 丁翔 《电池》 北大核心 2026年第1期215-221,共7页
正极材料是决定钠离子电池性能与成本的核心组件,其中金属层状氧化物因高能量密度和易合成性备受关注,但单一P2或O3相材料存在不可逆相变、扩散动力学差异等缺陷。阐述P2相与O3相的结构特征及性能,可通过P2/O3双相协同设计的界面互锁效... 正极材料是决定钠离子电池性能与成本的核心组件,其中金属层状氧化物因高能量密度和易合成性备受关注,但单一P2或O3相材料存在不可逆相变、扩散动力学差异等缺陷。阐述P2相与O3相的结构特征及性能,可通过P2/O3双相协同设计的界面互锁效应实现性能互补;介绍溶胶-凝胶法、固相法、共沉淀法在双相材料的应用场景;分析元素掺杂、高熵设计、结构调控及煅烧工艺优化改性策略的作用机制。双相协同与多策略结合,能够突破单一相材料性能瓶颈,为高性能钠离子电池正极材料的开发提供理论依据。 展开更多
关键词 钠离子电池 P2/O3相层状氧化物 元素掺杂 高熵设计 煅烧工艺优化
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催化层介孔碳载体结构对质子交换膜燃料电池多相反应输运影响的LB模拟研究
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作者 王誉霖 马飞 +3 位作者 秦世位 乔佳楠 张剑波 杨若曦 《电气工程学报》 北大核心 2026年第1期108-119,共12页
阴极催化层是质子交换膜燃料电池发生氧还原反应的关键场所,优化其碳载体结构对提升质子交换膜燃料电池性能至关重要。基于Shan-Chen伪势格子玻尔兹曼方法建立了耦合氧还原反应和组分传输的两相流模型,研究了质子交换膜燃料电池中具有... 阴极催化层是质子交换膜燃料电池发生氧还原反应的关键场所,优化其碳载体结构对提升质子交换膜燃料电池性能至关重要。基于Shan-Chen伪势格子玻尔兹曼方法建立了耦合氧还原反应和组分传输的两相流模型,研究了质子交换膜燃料电池中具有连通孔与梯度孔的介孔碳载体结构对阴极催化层内的氧还原反应与输运过程的影响。结果表明,相比非连通孔结构,连通孔介孔碳结构提供了充分的氧传输通道和排水路径。对于孔径深度为外6 nm里8 nm的梯度孔介孔碳载体催化层,随着外部孔径深度增加,氧还原反应速率先增大后减小,当外部孔深为3 nm时,氧还原反应速率最大;而孔为外8 nm里6 nm的梯度孔的氧还原反应速率均随着离聚物侵入比例增加而降低。因此,设计具有连通孔、并采用外小内大且外孔深度约3 nm的梯度孔介孔碳载体结构,可优化催化层内氧气传输、液态水排出,有效提升质子交换膜燃料电池性能。 展开更多
关键词 介孔碳载体结构 阴极催化层 格子玻尔兹曼方法 两相流 质子交换膜燃料电池
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HT300表面双层结构碳化钼复合涂层的微观组织和力学性能
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作者 梁小进 康玲 +1 位作者 白海强 王旭东 《表面技术》 北大核心 2026年第3期244-251,共8页
目的在钢铁材料表面制备硬质涂层,可明显改善其因表面硬度低和耐磨性差导致在摩擦工况下使用寿命低的问题。采用传统均质涂层在提高表面硬度和耐磨性的同时,通常伴随着韧性的大幅降低,即硬度(耐磨性)与韧性存在权衡关系,因此采用原位固... 目的在钢铁材料表面制备硬质涂层,可明显改善其因表面硬度低和耐磨性差导致在摩擦工况下使用寿命低的问题。采用传统均质涂层在提高表面硬度和耐磨性的同时,通常伴随着韧性的大幅降低,即硬度(耐磨性)与韧性存在权衡关系,因此采用原位固相扩散技术在HT300表面制备一种具有双层结构的新型碳化钼复合涂层。方法采用X射线衍射(XRD)、扫描电子显微镜(SEM)和背向散射电子衍射技术(EBSD)分析涂层的物相组成和微观形貌。用G200纳米压痕仪测试涂层截面的硬度和压入模量。通过维氏压痕测试实验评价涂层的断裂韧性。结果当制备工艺参数为1000℃、保温10 h时,涂层呈现致密结构,且涂层与基体之间无明显间隙。进一步将制备工艺参数优化为温度1050℃、保温时间10 h,所制备涂层的截面微观组织呈现典型的双层结构。从复合涂层表面到基体,第1层(Ⅰ)为完全致密的Mo_(2)C层,第2层(Ⅱ)为连接Mo_(2)C层与HT300基体的Fe_(3)Mo_(3)C(Si)过渡层。Mo_(2)C层/Fe_(3)Mo_(3)C(Si)层界面和Fe_(3)Mo_(3)C(Si)层/基体界面均呈现良好的冶金结合。当保温时间由4 h增加到10 h时,复合涂层的厚度由(15.9±0.46)μm增至(25.3±0.85)μm,且复合涂层厚度的平方与保温时间t成正比(d2=Kt,K=64.35μm^(2)·h)。压痕测试结果表明,复合涂层表面的硬度和断裂韧性分别达到(24.6±0.5)GPa和(3.0±0.1)MPa·m^(1/2)。相较于未涂覆的HT300基体((3.5±0.5)GPa),复合涂层表面的硬度提高了约6倍。沿着厚度方向,复合涂层的硬度逐渐降低,而断裂韧性逐渐增大。结论复合涂层内双层结构的形成可以降低复合涂层与基体之间的界面应力集中,进而改善了复合涂层与基体之间的界面结合。该新型钢铁材料表面双层结构的制备策略有效解决了钢铁材料表面硬度低和耐磨性不足的问题。 展开更多
关键词 固相扩散 双层结构 碳化钼复合涂层 微观组织 力学性能
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高熵P2/O3双相正极的协同设计助力高性能钠离子电池
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作者 赵珊 刘旭 +4 位作者 郭昊天 柳宗琳 王鹏飞 舒杰 伊廷锋 《物理化学学报》 北大核心 2026年第1期49-61,共13页
P2型层状过渡金属氧化物(P2-Na_(x)TMO_(2))因其优异的循环稳定性和倍率性能,成为钠离子电池正极材料的有力候选者。然而,其在高电压下的不可逆相变和固有低理论容量问题,阻碍了实际应用。本研究工作提出高熵策略与双相结构的协同设计... P2型层状过渡金属氧化物(P2-Na_(x)TMO_(2))因其优异的循环稳定性和倍率性能,成为钠离子电池正极材料的有力候选者。然而,其在高电压下的不可逆相变和固有低理论容量问题,阻碍了实际应用。本研究工作提出高熵策略与双相结构的协同设计来克服这些挑战。通过在P2相高熵基体中引入O3相,构建新型P2/O3双相高熵层状氧化物Na_(0.70)Ni_(0.25)Mn_(0.35)Co_(0.15)Fe_(0.05)Ti_(0.20)O_(2)(简称Na_(0.70)NMCFT)。其中,高熵设计通过构型熵稳定效应有效抑制P2相的不可逆相变,而O3相则通过协同作用弥补容量不足并提升循环稳定性。此外,双相组分之间的相互作用进一步促进P2-O3与P2-P3相变的高度可逆性。Na_(0.70)NMCFT在1C倍率下的初始放电容量为102.08 mAhg^(-1),200次循环后容量保持率达88.15%,表明具有优异的循环稳定性。更重要的是,即使在10C的高倍率下,Na_(0.70)NMCFT仍能提供85.67 mAh g^(-1)的初始放电比容量,并在1000次循环后容量保持率达70%。本工作证实双相高熵设计在提升钠离子电池正极性能中的关键作用,为开发先进钠离子电池正极材料提供了新思路。 展开更多
关键词 钠离子电池 层状氧化物正极 高熵 P2/O3双相 相变
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Sn-Bi基焊料界面可靠性关键问题与改性策略研究进展
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作者 赏敏 马海涛 +2 位作者 马浩然 王加俊 王云鹏 《表面技术》 北大核心 2026年第3期219-243,共25页
系统综述了旨在提升Sn-Bi焊点界面可靠性的多层次改性策略。首先,评述了通过焊料合金化调控其本征性能的方法,系统分析了添加Ag、Cu、Ni、In、Sb、Zn、Co等元素对焊料微观结构、力学性能及界面反应动力学的影响。其次,探讨了以石墨烯为... 系统综述了旨在提升Sn-Bi焊点界面可靠性的多层次改性策略。首先,评述了通过焊料合金化调控其本征性能的方法,系统分析了添加Ag、Cu、Ni、In、Sb、Zn、Co等元素对焊料微观结构、力学性能及界面反应动力学的影响。其次,探讨了以石墨烯为代表的纳米颗粒强化机制,阐明其在细化晶粒和抑制IMC生长方面的作用。随后,重点阐述了以基板改性为核心的界面工程策略,深入剖析了Ni基金属镀层和Ni-P、Ni-W-P等先进复合镀层作为扩散阻挡层的核心机理,即通过改变界面反应热力学路径来抑制原子互扩散。同时,也关注了复合改性方法,如焊料合金化与基板表面处理,如ENEPIG的协同作用。最后,对未来研究方向进行了展望,指出开发高熵/非晶合金等新型阻挡层,并结合计算材料学与先进原位表征技术,将是实现下一代高可靠性Sn-Bi焊点界面“按需设计”的关键。 展开更多
关键词 Sn-Bi焊料 界面可靠性 金属间化合物 Bi相偏析 合金化 扩散阻挡层 纳米增强
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