Results 31 to 40 of about 345,035 (139)

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

生物膜法强化低温反硝化

open access: yesGongye shui chuli, 2021
针对冬季温度低导致的脱氮效率下降问题,建立上流式固定床生物膜反应器(UFBR),并与传统活性污泥反应器(SASR)低温时的反硝化效果、微生物特性及群落结构进行比较,分析低温下生物膜的形成。经过160 d先逐步降温再提升硝酸盐进水负荷(NLR)的连续运行,UFBR表现出耐受低温能力强、脱氮效果优于SASR的特点;8℃下,UFBR的硝酸盐去除负荷(NRR)达到0.32 kg/(m3·d),比SASR高2倍多。低温下活性污泥产生大量胞外聚合物,发生污泥膨胀。而UFBR生物膜可分泌更多蛋白质 ...
赵楠楠   +5 more
doaj   +2 more sources

Rapid Removal of Binder From Spent Lithium‐Ion Batteries by Microwave Radiation for Enhanced Flotation Separation of Anode and Cathode Materials

open access: yesRare Metals, Volume 45, Issue 9, September 2026.
ABSTRACT Achieving rapid and selective separation of anode and cathode materials remains a critical challenge in the recycling of spent lithium‐ion batteries. This study develops a microwave‐enhanced flotation strategy for the efficient recovery of cathode and anode materials.
Peiyuan Ye   +5 more
wiley   +1 more source

Chemical Removal of Al From Layered Mn2AlB2: Toward 2D‐MBene and Its Application to MgH2 Hydrogen Storage

open access: yesRare Metals, Volume 45, Issue 9, September 2026.
ABSTRACT Two‐dimensional Mn‐based MBenes remain challenging to synthesize due to structural instability during etching. Herein, Mn2AlB2 was employed as a precursor to systematically investigate Al removal via HF, NaOH, and a gas–solid route using PVDF‐derived HF.
Tao Zhong   +6 more
wiley   +1 more source

低温低噪声放大器噪声测试系统

open access: yes, 2006
本文介绍了上海天文台低温低噪声放大器噪声测试系统的研制情况。该测试系统在现有的仪器设备基础上,利用负载温度可变法和低温衰减器法实现了低温低噪声放大器噪声参数的精确测量和快速测量。负载温度可变法实现了低噪声放大器噪声温度的精确测量,测试不确定度约为1K;低温衰减器法实现了低噪声放大器噪声温度的快速测量,测试不确定度低于4K。实验表明,两种测试方法至少可以在10MHz~10GHz频率范围内达到上述精度。目前,上海天文台已经用该测试系统验收了5台S波段和5台X波段进口低噪声放大器 ...
徐建军
core  

亚低温对大鼠局灶性脑缺血自由基和NO影响

open access: yesZhongguo shiyan zhenduanxue, 2004
目的研究亚低温状态下,大鼠急性脑缺血时氧自由基超氧化物歧化酶(SOD)和一氧化氮(NO)、一氧化氮合酶(NOS)的改变,探讨亚低温对缺血脑组织的保护机制。方法将45只Wistar大鼠随机分为9组,假手术组5只,缺血组及亚低温组又根据缺血、亚低温时间不同分为3h、24h、48h、72h亚组(各组均为5只)。动物模型参照Longa、Koizumi和刘亢丁等人的方法,采用颈内动脉线栓法制备大脑中动脉闭塞(MCAO)模型。结果比较缺血组和亚低温组,可见亚低温组栓塞侧脑组织SOD的生成和释放明显增加 ...
孙宏霞, 付铁娟, 刘亢丁
doaj  

Constructing Ultrafine Ru Nanoclusters via a Dual‐Confinement Strategy: Synergizing Hierarchical Pores and Electronic Modulation for Efficient Lignin Hydrogenolysis

open access: yesRare Metals, Volume 45, Issue 9, September 2026.
ABSTRACT Lignin hydrogenolysis is a promising route to separable aromatic monomers, yet practical upgrading is still hindered by macromolecular mass‐transfer limitations and the aggregation/deactivation of metal sites. Herein, we propose a “dual‐confinement” strategy to construct ultrafine Ru nanoclusters supported on lignin‐based N‐doped hierarchical ...
Tianjin Li   +11 more
wiley   +1 more source

避雷器在线监测装置的低温特性试验方法研究

open access: yesDianci bileiqi, 2018
对低温环境的适应性是部分地区避雷器在线监测装置运行中必然遇到的问题,需要研究相应的低温试验方法来确保监测装置在低温环境下的运行可靠性和测量准确性。根据自然环境低温分布特点及对电网影响的程度,总结了适用于电力系统的低温环境分类,可分为三类:-55℃-45℃,-45℃-20℃,-20℃0℃。根据避雷器在线监测装置结构,分析了低温环境对状态监测装置运行可靠性的影响因素,建议使用纯度较高的硅橡胶(VQM)和三元乙丙(EPDM)作为密封圈材料,建议使用温度特性更好的元器件来设计电源、采集系统等电子电路 ...
汤霖, 黄佳瑞, 侯文君
doaj  

Time‐Efficient Columnar‐to‐Equiaxed Transition via High Magnetic Field Processing

open access: yesRare Metals, Volume 45, Issue 9, September 2026.
ABSTRACT The need to simplify processing routes and improve processing efficiency motivates the development of time‐efficient methods for inducing the columnar‐to‐equiaxed transition (CET) during solidification while tailoring material performance. Conventional multistep CET approaches are time‐consuming and often struggle to simultaneously regulate ...
Chendong Zhao   +12 more
wiley   +1 more source

麻疯树活性氧水平及酶类清除系统对温度胁迫的差异应答研究

open access: yes四川大学学报. 自然科学版, 2015
本文测定并比较了低温(4℃)和高温(40℃)胁迫下,麻疯树幼苗叶片中的丙二醛、脯氨酸、可溶性糖、活性氧水平以及活性氧清除酶类的活性变化.研究发现在低温或高温胁迫下,活性氧(H2O2、O2-)含量均呈现出先保持不变后上升的趋势,而SOD、CAT、POD活性先上升后降低.在低温胁迫下,MDA、脯氨酸和可溶性糖含量随着胁迫时间增长而逐渐升高;而高温胁迫虽使MDA、脯氨酸含量增大,但变化趋势不如受冷胁迫的麻疯树变化明显,且高温胁迫未使可溶性糖含量发生明显变化 ...
蒋楠   +5 more
doaj  

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