Results 31 to 40 of about 2,077 (193)

Synergistic Electron Density and Oxygen Defect Regulation in Fluorite High‐Entropy Oxides for Superior Ionizing Radiation Shielding

open access: yesRare Metals, Volume 45, Issue 4, April 2026.
ABSTRACT Lightweight and lead‐free radiation shielding materials remain urgently needed. This work designed a fluorite high‐entropy oxide (FHEO) system through a combined computational–experimental route. Density functional theory based on special quasi‐random structures was used to identify thermodynamically stable fluorites from a wide compositional ...
Xiangjie Duan   +9 more
wiley   +1 more source

高压水射流注入液态铅铋的传热升压特性研究

open access: yesHe jishu
铅铋堆蒸汽发生器传热管两侧具有较大的压力差和温度差,而且铅铋冷却剂对换热管具有腐蚀作用,长期运行存在破裂的可能性。为揭示铅铋堆蒸汽发生器传热管破裂(Steam Generator Tube Rupture,SGTR)事故下铅铋池的传热升压机理,基于计算流体力学(Computational Fluid Dynamics,CFD)方法,通过耦合VOF(Volume of Fluid)模型、Realizable k-ε模型和Lee相变模型对高压水射流注入液态铅铋的相互作用过程进行数值模拟。结果表明 ...
胡 晗, 李 根, 梁 晓雯
doaj   +1 more source

Etnografia é, etnografia não é

open access: yesIlha Revista de Antropologia, 2017
Usando uma noção de "digital" como uma de suas metáforas principais, uma versão do termo que se apoia na discussão de Kara Keeling sobre o "humanismo digital", este texto argumenta que há algo sobre as não-linearidades que definem a diferença da digitalidade que pode nos ajudar a pensar sobre recalibragens no próprio projeto etnográfico.
Araujo, F. N., Jackson, John L.
openaire   +2 more sources

Broad‐Spectral Response Lead Halide Perovskite Solar Cells Through Integration of Multifunctional Organic Bulk‐Heterojunction and Quantum‐Cutting Downconversion Materials

open access: yesRare Metals, Volume 45, Issue 3, March 2026.
ABSTRACT Expanding near‐infrared (NIR) spectral response and utilizing ultraviolet (UV) photons are effective strategies for enhancing the power conversion efficiency (PCE) of lead halide perovskite solar cells (PSCs). However, the range of NIR spectral response extension and the utilization of UV light for devices are not enough, and the loss of ...
Li He   +9 more
wiley   +1 more source

菜地土壤铅、镉有效态与生物有效性研究

open access: yesShuitu Baochi Xuebao, 2011
通过野外采样、室内测试分析,探讨重庆市北碚区菜地土壤铅、镉的有效态含量及生物有效性。结果表明:研究区菜地土壤铅、镉有效态平均含量为3.114,0.051mg/kg,生物有效性系数分别为7.7%,25.1%;小白菜可食部分铅、镉平均含量分别为0.123,0.021mg/kg,富集系数分别为0.4%,9.8%;从富集系数和生物有效性系数看,研究区菜地土壤镉的潜在生态风险要大于铅的。研究区菜地土壤理化性质中pH对有效态镉有显著影响;砂粒、粘粒和有机质对有效态铅含量有显著影响;铅、镉有效态与全量变化一致 ...
袁波   +4 more
doaj  

静电喷涂无铅玻璃釉在金属氧化物电阻片制造中的应用研究

open access: yesDianci bileiqi, 2022
笔者深入研究了采用静电喷涂无铅玻璃釉工艺来制备金属氧化物电阻片的制造技术。研究内容包括:1)在一定配方比例的无铅玻璃釉粉料基础上,采用高速离心喷雾造粒制备所需要静电喷涂粉料;2)采用流化床静电喷涂机喷涂无铅玻璃粉料工艺;3)无铅玻璃粉料的热处理玻化;4)性能试验:以D42 mm×27 mm规格电阻片为例,可以满足4/10、120 kA的大电流冲击3次。从研究的结果来看:1)在金属氧化物电阻片制造中应用静电喷涂无铅玻璃釉,可以实现“无铅”化环保制造过程。2)材料的利用率达到85%,可以满足节约原料的目的 ...
赵冬一
doaj  

“Agro é tech, agro é pop, agro é tudo”?

open access: yesRevista Tamoios
O objetivo deste artigo é apresentar um panorama dos conflitos pela água produzidos e intensificados pelo agronegócio em Minas Gerais entre os anos de 2002 e 2022, a partir do aporte teórico-metodológico da Ecologia Política. Para tanto, foi desenvolvida uma pesquisa qualitativa, de caráter descritivo.
José Vitor Palhares dos Santos   +2 more
openaire   +1 more source

A Multifunctional Reducing Molecular Dopant for 16% Efficient Tin Perovskite Solar Cells

open access: yesRare Metals, Volume 45, Issue 3, March 2026.
ABSTRACT Although lead‐based photovoltaics have seen remarkable progress, tin‐based perovskite solar cells (Sn‐PSCs) continue to face challenges due to their limited power conversion efficiency and insufficient operational stability. The primary cause of this performance gap is the susceptibility of Sn2+ to oxidation, which promotes rapid defect ...
Xianyong Zhou   +12 more
wiley   +1 more source

外源铅在土壤中的形态、分布及其对土壤养分的影响

open access: yesShuitu Baochi Xuebao, 2008
通过对加入外源铅的砂姜黑土、黄褐土、红壤进行培养处理,测定土壤中各形态铅及水溶态NH4 ,K 和速效态磷的含量,研究外源铅在各类土壤中的形态分布特点及对土壤养分的影响。结果表明:交换态和残渣态的铅为红壤>黄褐土>砂姜黑土,碳酸盐态铅为砂姜黑土>黄褐土>红壤,铁锰氧化态铅为红壤>砂姜黑土>黄褐土,有机结合态铅为黄褐土>砂姜黑土>红壤;交换态和残渣态所占比例随着外源铅的浓度增大而提高,有机结合态的比例随着外源铅浓度增大降低,碳酸盐结合态铅在砂姜黑土、铁锰氧化态铅在红壤上则呈现外源铅小于500 m g ...
朱江   +4 more
doaj  

Conservation and health policy implications linked to the human consumption of sea turtles in northwestern Mexico 墨西哥西北部人类食用海龟一事对动物保护和健康政策的启示 Implicaciones para las políticas de conservación y salud vinculadas al consumo humano de tortugas marinas en el noroeste de México

open access: yesWorld Medical &Health Policy, Volume 16, Issue 1, Page 57-69, March 2024.
Abstract Human consumption of sea turtles remains prevalent throughout Mexico even though laws restricting trade and take of threatened and endangered species have been in place for several decades. The illegal consumption of sea turtles represents a risk to animal conservation, and the pathogens in the meat can adversely affect human health.
A. Alonso Aguirre   +6 more
wiley   +1 more source

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