Results 11 to 20 of about 11,900 (124)

尿素与复合氮肥增效剂配施对水稻氮素利用的影响

open access: yesShuitu Baochi Xuebao, 2006
采用^15N-尿素进行盆栽和田间试验,研究了复合氮肥增效剂用量、尿素与复合氮肥增效剂配施对水稻生长、籽粒产量和氮素吸收利用的影响。结果表明,适宜用量(施氮量的20%)的复合氮肥增效剂能显著促进水稻幼苗生长发育;尿素全量配施复合氮肥增效剂不影响水稻生长,能显著提高水稻植株Ndff%、氮吸收总量,氮素利用率和^15N的吸收量,尿素减量5%~15%(即减少施氮7.8~23.7kg/hm^2)配施复合氮肥增效剂基本上不影响水稻生长、籽粒产量和吸氮总量,能显著提高氮素的农学效率、生理效率和氮素利用率;植株吸氮总量、
田秀英, 王正银
doaj   +2 more sources

Bidentate Coordination by Graphene Oxide‐Enhanced γ‐Cyclodextrin for Synergistic Solvation and Stabilization of the Zn Anode

open access: yesRare Metals, EarlyView.
ABSTRACT With the rapid development of the energy storage industry, aqueous zinc‐ion batteries (AZIBs) have attracted considerable attention in the field of energy storage because of their inherent advantages, thereby emerging as a promising research direction with significant potential.
Lingjiao Fu   +8 more
wiley   +1 more source

Fabrication‐Driven Oxidation Pathways in Y/Hf‐Modified High‐Entropy Alloys: From Elemental Segregation to Oxide Homogeneity

open access: yesRare Metals, EarlyView.
ABSTRACT This study elucidates the oxidation mechanisms governing Y/Hf‐doped AlCoCrFeNiTi high‐entropy alloys (HEAs) and reveals the pivotal role of fabrication processes in dictating high‐temperature oxidation behavior. We demonstrate that casting and spark plasma sintering (SPS) promote Y/Hf segregation, resulting in heterogeneous oxide formation and
Huaqing Yi   +5 more
wiley   +1 more source

High‐Coercivity Nd2Fe14B/α‐Fe Nanocomposites With Ultrafine Nanocrystalline Structure via Zr‐Induced Synchronous Precipitation

open access: yesRare Metals, EarlyView.
ABSTRACT Nanocomposite permanent magnets with reduced rare‐earth content represent a promising class of materials for next‐generation high‐performance applications. However, asynchronous precipitation of soft and hard magnetic phases often results in grain size mismatch and limited coercivity.
Xiaowei Zhang   +6 more
wiley   +1 more source

In Situ MOF Pyrolysis Construction of Hierarchical Porous Co‐Nanoparticles/Carbon Cloth Composites for Enhanced Electromagnetic Wave Shielding and Absorption

open access: yesRare Metals, EarlyView.
ABSTRACT The development of high‐performance electromagnetic protection materials integrating broadband absorption and effective shielding capabilities is hindered by challenges in simultaneously optimizing multiple electromagnetic properties through conventional material designs.
Changlong Du   +9 more
wiley   +1 more source

Coalescence‐Ripening Mechanism of γ′−Ni3(Al, Ti) During Long‐Term/High‐Temperature Operation of Ni‐Based Superalloy Discs

open access: yesRare Metals, EarlyView.
ABSTRACT The evolution of the γ′−Ni3(Al, Ti) phase in superalloys is governed by a coupled coalescence‐ripening mechanism driven by elemental diffusion. In this study, thermal exposure experiments were performed at 750°C and 800°C for durations ranging from 100 to 20,000 h.
Zhaotian Wang   +5 more
wiley   +1 more source

基于10/350μs波形下不同压敏电压的限压型浪涌保护器间能量配合研究

open access: yesDianci bileiqi, 2019
浪涌保护器(Surge protective device,SPD)对于保障电气、电子设备免于雷击风险有着至关重要的作用。为实现电气、电子系统过电压保护,必须安装两级或多级合理能量配合SPD。针对SPD间能量配合问题,利用10/350μs波形对I类、II类SPD并联能量配合问题进行研究,得出以下结论:当SPD间无专门退耦装置时,限压型SPD间的线路特性阻抗对于其间能量配合起到关键作用。当第一级SPD压敏电压高于第二级,且SPD间距离短、冲击浪涌电流较小时,SPD间能量配合失效 ...
程智余, 沈淼, 邱宏瑜
doaj  

On the Damage Tolerance of Diffusion Bonded Titanium–Aluminum Phase Biomimetic Composites

open access: yesRare Metals, EarlyView.
ABSTRACT The biomimetic design principles of natural structures involve the strategic integration of stiff and compliant phases to synergistically enhance strength and toughness. Its evolutionary refined natural armor, characterized by a specialized microarchitecture, enables superior damage tolerance.
Shuai Tong   +10 more
wiley   +1 more source

Optimizing the Surface Coordination of Pd‐Cu Nanoalloy Through Chemical Ordering to Enhance Hydrogenation Selectivity

open access: yesRare Metals, EarlyView.
ABSTRACT Precise control of chemical ordering in bimetallic nanocatalysts offers a route to decouple activity and selectivity in acetylene hydrogenation, but direct atomic‐scale evidence linking surface order to catalytic performance is scarce. Here, we tune Pd‐Cu nanoalloys from chemically disordered to highly ordered states by composition control and
Fan Xue   +5 more
wiley   +1 more source

标准衰减振荡波下压敏电阻能量配合研究

open access: yesDianci bileiqi, 2017
为了有效利用压敏电阻对真实雷电过电压进行防护,需要对标准衰减振荡波下压敏电阻能量配合进行研究。利用EMTP软件搭建0.5μs-100 k Hz标准振荡波发生电路,采用IEEE压敏电阻模型进行仿真冲击。分析前后级压敏电阻采用高低配合与低高配合方式的防护效果。最后讨论不同前后级压敏电阻连接导线长度对分流和能量吸收的影响。分析结果表明:压敏电阻残压随着充电电压的增加而增大,低高配合方式下,前级压敏电阻承受了绝大部分雷电流和能量,配合效果不如高低配合方式。前后级连接导线长度增加时,流过前级和后级的电流峰值均降低,
苏奎, 马媛媛
doaj  

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