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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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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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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 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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激光烧结Al_(x)CoCrFe_(y)Ni高熵合金的高温氧化行为 被引量:2
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作者 李刚 孟祥然 +2 位作者 李思南 周琳涵 王崇铄 《稀有金属》 北大核心 2025年第1期57-67,共11页
为了探究高熵合金在高温环境中的稳定性和Al,Fe元素对高温抗氧化性能的影响,本文研究了Al_(x)CoCrFe_(y)Ni (x=1.5,2;y=1,1.25,1.5)系高熵合金在900℃的高温氧化行为。采用激光烧结技术制备Al_(x)Co Cr Fe_(y)Ni合金,将合金放置于900℃... 为了探究高熵合金在高温环境中的稳定性和Al,Fe元素对高温抗氧化性能的影响,本文研究了Al_(x)CoCrFe_(y)Ni (x=1.5,2;y=1,1.25,1.5)系高熵合金在900℃的高温氧化行为。采用激光烧结技术制备Al_(x)Co Cr Fe_(y)Ni合金,将合金放置于900℃的流动空气中加热100 h,测试随加热时间,合金的质量变化,建立合金氧化动力学模型。通过X射线衍射(XRD)、扫描电镜(SEM)和能谱(EDS)分析合金氧化层的物相组成和形貌,研究合金的高温氧化机制。结果发现,激光烧结制备的Al_(x)CoCrFe_(y)Ni系高熵合金为体心立方(bcc)相或者bcc+少量面心立方(fcc)双相的固溶体结构。在900℃加热100 h的高温氧化过程中,合金的氧化动力学曲线符合抛物线规律,Al_(2)CoCrFeNi合金的氧化增重曲线抛物线速率常数K_(T)=0.5345,其值最小,具有较好的抗氧化性能。合金的氧化层物相相近,均由细小密集堆叠的Cr_(2)O_(3)相、致密的富Al尖晶石相、不含Al元素片层状堆叠的富Fe尖晶石相和珊瑚状的富Co尖晶石相组成。与带有孔隙不含Al的尖晶石相相比,Al,Cr元素的氧化物连续且致密,对合金基体保护性更好。高熵合金中Al元素含量增加,合金的高温抗氧化性能增强;Fe元素含量增加,合金高温抗氧化性能减弱。激光烧结制备的Al_(x)CoCrFe_(y)Ni系高熵合金的孔隙率高于铸态合金,孔隙加速了合金的高温氧化行为。高熵合金的高温抗氧化性能与组成元素的氧化激活能有关,通过成分优化和工艺控制能够改善高熵合金的高温稳定性,拓展合金的应用范围。 展开更多
关键词 高熵合金 激光烧结 高温氧化 氧化层 尖晶石相
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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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基于动态区域划分的配电网台区三相不平衡治理策略
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作者 陈晓龙 徐颖 李斌 《电力自动化设备》 北大核心 2025年第8期208-216,共9页
传统三相不平衡治理仅关注变压器关口处的三相不平衡情况,忽略了台区内部不平衡特征,且多采用静态调相策略,难以适应灵活源荷接入下低压配电网运行状态的动态变化。为此,提出了一种基于动态区域划分的三相不平衡治理策略。提出基于分区... 传统三相不平衡治理仅关注变压器关口处的三相不平衡情况,忽略了台区内部不平衡特征,且多采用静态调相策略,难以适应灵活源荷接入下低压配电网运行状态的动态变化。为此,提出了一种基于动态区域划分的三相不平衡治理策略。提出基于分区评价指数与阈值触发机制的动态分区方法,以划定后续相序优化的区域范围。建立考虑多类型灵活调节资源的双层优化模型,上层以各分区三相不平衡度最小为目标优化相序配置,下层构建以运行成本最小为目标的电压优化模型。采用基于云模型改进的遗传算法和Gurobi求解器分别求解上下层模型。基于改进的IEEE 123节点系统和0.38 kV实际配电网台区进行仿真,验证了所提策略的有效性与优越性。 展开更多
关键词 配电网 三相不平衡 动态分区 双层优化模型 相序优化 云模型 遗传算法
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苏南地区一次罕见冰粒天气成因
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作者 雷正翠 吴海英 +4 位作者 温静 黄文彦 夏束薇 李斌 钱雨妃 《气象科技》 2025年第3期405-416,共12页
利用多源观测资料、再分析资料,对2024年2月22-24日苏南地区的罕见冰粒天气进行了分析,并对冰粒、冻雨、雪三种相态进行了比较。结果表明:700 hPa西南暖湿急流强盛且稳定维持,为冰粒天气的形成提供了有利的动力、水汽和温度层结条件,中... 利用多源观测资料、再分析资料,对2024年2月22-24日苏南地区的罕见冰粒天气进行了分析,并对冰粒、冻雨、雪三种相态进行了比较。结果表明:700 hPa西南暖湿急流强盛且稳定维持,为冰粒天气的形成提供了有利的动力、水汽和温度层结条件,中层暖湿气流的发展具有显著的极端性,苏南地区700 hPa高度场较常年气候平均值偏高10~30 gpm(标准差倍数达0.5~1个标准差σ),西南风偏强10 m·s^(-1),温度偏高4~5℃(标准差倍数≥1.5σ),中层异常偏暖是苏南地区出现罕见的长时间冰粒天气的重要条件之一。逆温层稳定存在,位于939.8~729.9 hPa之间,平均厚度为1540 m,平均强度为10.2℃。稳定维持的中层暖层和低层冷层为冰粒天气的出现提供了有利的温度层结条件:暖层的平均厚度为709 m,高度位于779.3~683 hPa之间,暖层温度≤2.9℃;冷层基本位于779.3 hPa以下,最低温度为-8.7~-7.6℃,有利于被暖层部分融化的冰相粒子在下降过程中再次被冻结,最后以冰粒相态降落至地面。冰粒、冻雨、雪三种相态的雷达特征存在差异,对降水相态的识别和相态临近预报有一定指示意义:雪的反射率因子在30 dBz以下,而冰粒和冻雨的反射率因子较强,一般在45 dBz以下;差分反射率因子(Z_(DR))大小为冰粒>冻雨>雪,其中冰粒的Z_(DR)最大达4 dB;从相关系数看,冰粒最小,而冻雨和雪接近于1。 展开更多
关键词 冰粒 标准差 暖层 冷层 降水相态
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基于相场法的质子交换膜电解水阳极扩散层两相流研究
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作者 王志明 赵培羽 +5 位作者 张自明 王铁营 郭浩 刘圣春 徐超 胡开永 《工程热物理学报》 北大核心 2025年第2期603-609,共7页
本文基于相场法通过COMSOL软件建立了质子交换膜电解水阳极扩散层两相流动的二维瞬态模型,详细分析了氧气在扩散层两相流动中的运动状态,同时研究了液态水流速、接触角、表面张力等参数的影响。结果表明,液态水流速的改变不影响多孔传... 本文基于相场法通过COMSOL软件建立了质子交换膜电解水阳极扩散层两相流动的二维瞬态模型,详细分析了氧气在扩散层两相流动中的运动状态,同时研究了液态水流速、接触角、表面张力等参数的影响。结果表明,液态水流速的改变不影响多孔传输层中氧气输运路径,但影响气泡脱离多孔传输层及气泡到达出口的时间;接触角对流域内氧气的输运具有双重作用;减小表面张力有利于氧气突破限制孔喉,能够使催化层产生的氧气尽快离开扩散层,有效地提高电池性能。 展开更多
关键词 质子交换膜电解水 阳极扩散层 相场法 氧气 两相流动
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钠离子电池层状过渡金属氧化物正极材料研究进展
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作者 陈东 《灯与照明》 2025年第4期236-238,共3页
钠离子电池因资源丰富、成本低及安全性高,成为储能领域的重要研究方向。层状过渡金属氧化物(Na_(x)TMO_(2))正极材料因高比容量和结构多样性备受关注。本文简要综述了钠离子电池层状过渡金属氧化物正极材料不同的相结构类型和相应的研... 钠离子电池因资源丰富、成本低及安全性高,成为储能领域的重要研究方向。层状过渡金属氧化物(Na_(x)TMO_(2))正极材料因高比容量和结构多样性备受关注。本文简要综述了钠离子电池层状过渡金属氧化物正极材料不同的相结构类型和相应的研究进展,探讨了各种类型的层状氧化物正极材料在应用中存在的问题及可行的改性方案,为钠离子电池层状过渡金属氧化物正极材料的进一步发展提供参考。介绍了P2相层状氧化物、O3相层状氧化物,认为层状过渡金属氧化物(Na_(x)TMO_(2))作为钠离子电池正极材料,凭借高比容量和可调结构展现出广阔前景。 展开更多
关键词 钠离子电池 正极材料 层状过渡金属氧化物 P2相 O3相
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在碳化物陶瓷中构筑金属原子层分相共生结构
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作者 鲍伟超 郭晓杰 +5 位作者 辛晓婷 彭湃 王新刚 刘吉轩 张国军 许钫钫 《无机材料学报》 北大核心 2025年第1期17-22,共6页
在保持结构陶瓷高硬度的同时提高其韧性和塑性,可以显著拓展其在极端环境中的应用前景,其中微结构设计是一项重要策略。本工作研究了在碳化物陶瓷中构筑金属单原子层分相共生结构的可行性。以过渡金属单质、石墨和少量Al为原材料,采用... 在保持结构陶瓷高硬度的同时提高其韧性和塑性,可以显著拓展其在极端环境中的应用前景,其中微结构设计是一项重要策略。本工作研究了在碳化物陶瓷中构筑金属单原子层分相共生结构的可行性。以过渡金属单质、石墨和少量Al为原材料,采用放电等离子体烧结工艺在1900℃和30 MPa压力下制备不同组元数的过渡金属碳化物陶瓷,发现只有高熵(TiZrHfNbTa)C陶瓷形成了Al原子层分相共生结构。该结构不是长程序的单相化合物(如MAX相),而是一种无周期性的碳化物和金属单原子层交叉堆叠的复合物。通过纳米至原子尺度的球差校正透射电子显微镜和能谱表征,揭示了少量Al单原子层无周期性地嵌入高熵碳化物面心立方结构的{111}面。结合第一性原理计算,发现形成原子层分相共生结构的关键因素不是Al在不同碳化物晶格中的扩散差异,而是高熵带来的热力学稳定性、晶格畸变和迟滞扩散效应等。本研究有助于推动结构陶瓷中原子尺度微结构的设计和调控,从而获得硬度-强度-韧性综合力学性能优异的结构陶瓷。 展开更多
关键词 结构陶瓷 高熵碳化物陶瓷 金属原子层分相 共生结构
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气体扩散层梯度孔隙率结构对质子交换膜燃料电池性能的影响
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作者 陈昕 叶丁丁 +4 位作者 汪洋 朱恂 杨扬 陈蓉 廖强 《工程热物理学报》 北大核心 2025年第10期3251-3257,共7页
质子交换膜燃料电池阴极存在复杂的水管理问题,气体扩散层内气液输运过程至关重要。为提升阴极水管理能力,本文提出四种具有不同方向梯度孔隙率结构的气体扩散层,构建三维非等温两相质子交换膜燃料电池数学模型,并通过设置极限电流密度... 质子交换膜燃料电池阴极存在复杂的水管理问题,气体扩散层内气液输运过程至关重要。为提升阴极水管理能力,本文提出四种具有不同方向梯度孔隙率结构的气体扩散层,构建三维非等温两相质子交换膜燃料电池数学模型,并通过设置极限电流密度对传质损失进行修正,探究梯度孔隙率结构对气液两相输运及性能的影响。结果表明,在靠近催化层和阴极入口处具有较高孔隙率的扩散层结构能有效降低阴极液态水饱和度,增强氧气传质,提升电池在高电流密度下的电化学性能,梯度孔隙率结构对于低电流密度下的性能影响较小。 展开更多
关键词 质子交换膜燃料电池 梯度孔隙率 气体扩散层 两相模型
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PBI基/PIM-1复合离聚物提高碱性膜氢燃料电池性能
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作者 王蕾蕾 吴雪梅 +3 位作者 陈婉婷 逄博 崔福军 贺高红 《膜科学与技术》 北大核心 2025年第5期133-142,共10页
本研究提出一种用于碱性阴离子交换膜燃料电池(AEMFC)催化层的新型复合离聚物设计。该设计将高离子传导性的亲水聚合物(UTA-PBI-25%)与具有微孔结构的疏水聚合物(PIM-1)相结合。亲水组分提供优异的离子传导性和催化剂结合能力,而疏水微... 本研究提出一种用于碱性阴离子交换膜燃料电池(AEMFC)催化层的新型复合离聚物设计。该设计将高离子传导性的亲水聚合物(UTA-PBI-25%)与具有微孔结构的疏水聚合物(PIM-1)相结合。亲水组分提供优异的离子传导性和催化剂结合能力,而疏水微孔组分则有效抑制溶胀并显著增强催化层的透气性。优化配比后的复合离聚物实现了催化层结构的协同改善,使其在催化剂分散、电化学性能和电极反应效率方面表现优异。应用于氢氧燃料电池时,该复合离聚物显著提升了电池在高电流密度下的输出性能,获得了高水平的峰值功率密度。这种“亲水黏结剂-疏水造孔剂”复合策略有效兼顾了催化层对离子传导性和气体传质能力的需求,为优化AEMFC性能提供了新思路。 展开更多
关键词 离聚物 聚苯并咪唑 自聚微孔聚合物(PIMs) 催化层三相界面 燃料电池
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青藏高原东北缘构造特征与分层各向异性 被引量:1
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作者 夏新宇 高原 《地震学报》 北大核心 2025年第1期1-20,共20页
本文综合前人在青藏高原东北缘利用不同方法不同资料得到的地震各向异性结果,对该地区断裂和应力等构造特征及分层各向异性进行了分析。结果表明,青藏高原东北缘以地壳缩短增厚变形为主,部分区域存在各向异性分层或壳内韧性层。XKS(SKS,... 本文综合前人在青藏高原东北缘利用不同方法不同资料得到的地震各向异性结果,对该地区断裂和应力等构造特征及分层各向异性进行了分析。结果表明,青藏高原东北缘以地壳缩短增厚变形为主,部分区域存在各向异性分层或壳内韧性层。XKS(SKS,PKS和SKKS震相的统称)分裂的快波方向整体呈NW或WNW向,与上地幔物质的流动有关。地壳的快波方向表明地壳变形会受到断裂及主压应力的影响。祁连造山带和海原断裂带的分层各向异性特征揭示了上地壳与中下地壳可能存在解耦。阿拉善地块东部至鄂尔多斯地块西部可能存在壳幔解耦现象,上下两层的变形机制不同。秦岭造山带表现为较强的壳幔耦合。松潘—甘孜地块的分层特征及其变形机制较为复杂,仍然存在争议。 展开更多
关键词 青藏高原东北缘 各向异性分层 XKS震相 接收函数 剪切波分裂 壳幔变形特征
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