Results 11 to 20 of about 28,550 (128)
, 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
, 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
, 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
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, 1957 在前文中我们已经给出小球在不均匀流场中运动时所受到的阻力。本文中我们假定泥沙和水为两种不同的介质,同时假定泥沙的浓度很小。利用前文所得到的阻力公式,我们建立了在层流状态时泥沙和水各自的运动方程组。然后利用这一组方程来讨论明渠中水流流态为层流时泥沙沉淀的情况。最后我们得到泥沙和水的相对速度在主流方向的分量并不等于零。同时我们求得根据简单假定来计算时所引起的沉积位置的误差。这个误差和水深成正比而和泥沙颗粒的大小无关。一般说来 ...
蔡树棠
core +2 more sources
, 1956 一.引言 在工程上一般碰到泥沙在水中运动的时侯,都应用斯托克斯公式来计算泥沙所受到的阻力。但是斯托克斯公式是一个圆球在无穷的粘性流体中作匀速运动时的阻力定律,对于很多砂子同时下沉作非匀速运动时,斯托克斯公式显然不能应用 ...
蔡树棠
core +2 more sources
Rare 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
Rare 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
Gongye shui chuli, 2020 采用聚合氯化铝铁混凝处理兰州夏季超高浊度黄河水，通过单因素实验考察了混凝剂投加量、沉淀比表面负荷及沉淀时间对处理效果的影响，并以响应面法对这些因素进行了优化。结果表明，各因素对浊度去除率、CODMn去除率的影响次序：混凝剂投加量>沉淀比表面负荷>沉淀时间；最佳混凝条件：混凝剂投加量640 mg/L，沉淀比表面负荷0.08 m3/m2，沉淀时间32 min。在最佳条件下，浊度和CODMn的平均去除率分别为98.62%、98.14%，与模型预测值相对偏差分别为0.5%、0.86%。
谢慧娜, 李杰, 朱雪燕, 边云峰
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Rare 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
Organ‐specific ozone and nitrogen legacies strengthen substrate control over litter decomposition
Functional Ecology, Volume 40, Issue 8, Page 2548-2559, August 2026.Read the free Plain Language Summary for this article on the Journal blog. Abstract Elevated tropospheric ozone (O3) and nitrogen (N) deposition are concurrent atmospheric changes that strongly influence terrestrial carbon cycling, yet their combined effects on below‐ground decomposition remain poorly understood.
Xiaofan Hou +8 more
wiley +1 more source