Results 11 to 20 of about 29,855 (152)

添加表面活性剂两步沉淀法制备甲醇催化剂

open access: yes, 2005
采用添加表面活性剂两步沉淀法制备了具有高表面铜相对浓度的超细甲醇合成催化剂:以组成为H2/CO/CO2/N2=66/27/3/4(体积比)的原料气对催化剂进行了活性评价。结果表明,该催化剂比传统并流沉淀法制备的铜基催化剂活性提高47.9%.比两步沉淀法和添加表面活性剂并流沉淀法制备的铜基催化剂活性分别提高9.3%和16.8%。利用SEM、XRD及XPS方法对催化剂的结构 ...
王铁军   +4 more
core   +5 more sources

浅谈研究所资金沉淀问题

open access: yes, 2005
随着中国科学院知识创新工程的实施,各研究所财政补贴收入也大量增加,货币资金存量也随之增长,因而在科研资金的管理上也出现了新的问题,如存在不同程度的“资金沉淀”现象。本文分析了“资金沉淀”现象产生的原因及其弊端,“资金沉淀”的种类 ...
董耕宇, 廖彩菊
core   +4 more sources

改进共沉淀法制Cu基甲醇催化剂

open access: yes, 2004
采用传统共沉淀法和加表面活性剂改进共沉淀法制备了两种超细Cu/ZnO/Al2O3催化剂,并应用XRD,TEM对催化剂的结构和形貌进行了表征,同时用流动固定床微型反应器在3.0MPa和体积空速7600h^-1下考察了其催化合成气合成甲醇的活性.结果表明,改进共沉淀法制备的超细Cu/ZnO/Al2O3催化剂具有比传统共沉淀法制备的催化剂更细的粒径和更高的催化活性 ...
常杰, 阴秀丽, 付严, 汪俊锋
core   +4 more sources

In Situ Rare Earth Nanoparticle Reinforcement of NiCoCrAlYTa Coatings via HCPEB Modification: Insights Into Early Oxidation Behavior and Microstructural Evolution

open access: yesRare Metals, Volume 45, Issue 9, September 2026.
ABSTRACT NiCoCrAlYTa coatings are widely used as bond coats in thermal barrier coating (TBC) systems for gas turbines and aeroengines to provide oxidation resistance and support the formation of a protective thermally grown oxide (TGO). Herein, high‐current pulsed electron beam (HCPEB) modification was utilized to strengthen a NiCoCrAlYTa coating by ...
Xiangcheng Li   +6 more
wiley   +1 more source

Overcoming Thermodynamic and Kinetic Constraints of Recrystallization and Precipitation in Cu‐Ni‐Sn Alloy via Electropulsing Treatment

open access: yesRare Metals, Volume 45, Issue 9, September 2026.
ABSTRACT The performance optimization of ultrahigh‐strength Cu‐15Ni‐8Sn alloy relies on controlling recrystallization and aging precipitation, which are two thermally activated processes constrained by high activation barriers. Conventional heat treatment requires elevated temperatures and prolonged holding time, inevitably leading to grain coarsening ...
Fei Tan   +10 more
wiley   +1 more source

Uncovering Cu Involved Nanophase Structures and Transformation in a Novel 7075B Aluminum Alloy

open access: yesRare Metals, Volume 45, Issue 9, September 2026.
ABSTRACT In this study, aberration‐corrected transmission electron microscopy combined with first‐principles calculations was employed to systematically investigate the Cu‐involved crystal structures and evolution mechanisms of nanoprecipitates in a novel 7075B Al alloy. Firstly, an atomic model of the early‐stage GP‐ηp structure together with specific
Deyu Zhang   +13 more
wiley   +1 more source

Rational Design of Bimetallic MOF‐Derived Cu/Co@N‐C Nanocubes for Ultrasensitive Electrochemical Nitrite Detection

open access: yesRare Metals, Volume 45, Issue 8, August 2026.
ABSTRACT A facile coprecipitation‐pyrolysis strategy was employed to fabricate Cu/Co nanoparticles (NPs) embedded in nitrogen‐doped carbon matrices (Cu/Co@N‐C) through the carbonization of CuCo‐MOF precursors. Moreover, monometallic counterparts of Cu@N‐C and Co@N‐C were also prepared via carbonization of bimetallic CuZn‐MOF and CoZn‐MOF, respectively.
Weinan Yao   +7 more
wiley   +1 more source

Tailoring a Dual‐Scale Heterostructure With γ‐Textures and Nano‐β0 Dispersion for Synergistic Enhancement of Mechanical Properties of TiAl Alloy

open access: yesRare Metals, Volume 45, Issue 8, August 2026.
ABSTRACT The limited crack resistance of coarse grain boundaries and coarse interfaces leads to an incompatibility between high‐temperature strength and ductility in TiAl alloys. Tailoring stress‐oriented textures and multiscale heterogeneous interfaces can effectively impede crack propagation, thereby overcoming this trade‐off.
Kexuan Li   +7 more
wiley   +1 more source

Microstructure Tailoring of Laser Powder Bed Fused Nb521 Alloy Toward Strength‐Ductility Synergy

open access: yesRare Metals, Volume 45, Issue 8, August 2026.
ABSTRACT Niobium‐based refractory alloys are promising candidates for high‐temperature aerospace structures, yet their limited ambient‐temperature ductility and poor processability remain major barriers to broader implementation. Here, Nb521 alloy was fabricated by laser powder bed fusion (LPBF), and the effects of processing conditions and subsequent ...
Lele Qin   +7 more
wiley   +1 more source

Dual‐Bioactive Lignin‐Based Microcarrier Hydrogel Platform via Metal Salt Crosslinking for Synchronized Infection Eradication and Bone Regeneration

open access: yesRare Metals, Volume 45, Issue 8, August 2026.
ABSTRACT Infected bone defects represent a dual therapeutic challenge demanding concurrent infection inhibition and osteogenesis promotion. Systemic antibiotic administration is taken as a classical treatment protocol but often yields inadequate local antibiotic concentrations and delayed bone repair.
Xucai Wang   +8 more
wiley   +1 more source

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