Results 21 to 30 of about 14,720 (193)

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

Physiological Responses of Carbon and N2 fixation of Trichodesmium IMS101 to Environmental Changes [PDF]

open access: yes, 2015
CO2和光是影响海洋浮游植物最重要的环境因子,未来海洋将面临这两方面的变化:一方面,大气CO2的升高使得全球变暖的同时导致海洋酸化(海水pH下降),并引起海洋低氧化。另一方面,海洋升温导致的上部混合层变浅,使得浮游植物在该层内接受可见光与UV辐射量增加。这些海洋环境的变化会对浮游植物、初级生产力及关键生态过程产生深远的影响。目前,多数研究聚焦于硅藻和钙化藻类对这些环境变化的响应,而有关固氮蓝藻的报道很少。束毛藻可贡献高达一半的全球海洋生物固氮量,直接影响寡营养海域的初级生产力及其它生态过程。为此 ...
蔡晓霓
core  

A Micro‐Nano Flower‐Like Na3V2(PO4)3@C Constructed by Polar‐Driven H‐Bond Engineering Toward High‐Rate Sodium Storage

open access: yesRare Metals, EarlyView.
ABSTRACT The polyanionic compound Na3V2(PO4)3 (NVP) has emerged as a competitive cathode material for sodium‐ion batteries (SIBs), owing to its high‐voltage redox activity (3.4 V vs. the Na+/Na reference couple) and NASICON‐type framework that enables superior ionic conductivity.
Xiaolei Wu   +5 more
wiley   +1 more source

亚低温对大鼠局灶性脑缺血氧自由基和一氧化氮的影响

open access: yesZhongguo shiyan zhenduanxue, 2009
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:3 h2、4 h4、8 h7、2 h亚组(各组均为5只)。采用颈内动脉线栓法制备大鼠大脑中动脉闭塞(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超氧化物歧化酶(SOD)的生成和释放明显增加;亚低温组血清中一氧化氮(NO ...
林淑香   +3 more
doaj  

Study on phytoplankton community similarity and ecological connectivity in northern Beibu Gulf [PDF]

open access: yes, 2015
浮游植物是海洋生态系统中主要的初级生产者,是构成海洋生态系统食物网的基础环节,其种类变化和群落结构直接影响海洋生态系统的结构和功能,在海洋生态系统的物质循环和能量流动过程中起着重要作用。本文以2006~2007年于北部湾进行的四个航次的调查数据,分析了北部湾北部浮游植物的种类组成、数量变化、群落结构以及生物多样性,探讨了浮游植物的群落演替和群落相似性及生态连通性的调控机制,获得主要结果如下: (1)北部湾北部浮游植物四季共鉴定273种(含变种和变型),隶属于5门78属,种类组成以广温类和暖水类为主 ...
王符菁
core  

Achieving High‐Performance SiO@C Anode of Li‐Ion Batteries via a One‐Step Prelithiated Preparation Strategy

open access: yesRare Metals, EarlyView.
ABSTRACT Silicon oxide (SiO) is becoming the main anode for high‐energy lithium‐ion batteries because of its ease of manufacture, outstanding cycling stability, and high capacity. However, low initial Coulombic efficiency (ICE) caused by the irreversible reaction of silica, as the main issue, strictly limits its commercial applications.
Hailong Mei   +5 more
wiley   +1 more source

F‐Mediated Precise Control Over Amorphous/Crystalline Fe/Ni‐Based Phosphides Heterostructure for Efficient Oxygen Evolution Reaction

open access: yesRare Metals, EarlyView.
ABSTRACT Transition metal‐based amorphous/crystalline (a/c) heterostructured catalysts have garnered significant attention due to their exceptional activity, stability, and cost‐effectiveness. However, the precise synergistic regulation of interfacial composition and phase states remains challenging.
Haoran Li   +3 more
wiley   +1 more source

经鼻高流量氧疗应用于重症肺部感染拔管后序贯干预的可行性研究

open access: yesZhongguo shiyan zhenduanxue, 2023
目的 探究经鼻高流量氧疗(HFNC)应用于重症肺部感染拔管后序贯干预的可行性。方法 选取2021年1月至2021年8月期间南通市海门区人民医院收治的82例重症肺部感染呼吸机支持的患者,根据随机数字表法将其分为观察组和对照组,每组各41例,两组机械通气拔管后,观察组采用HFNC治疗,对照组采用常规氧疗,比较两组患者治疗前,治疗24 h后呼吸功能指标[呼吸频率(R)、血氧饱和度(SPO2)],治疗前、治疗6 h、12 h及24 h的血气指标[氧合指数(PaO2/FiO2)、动脉血氧分压(PaO2 ...
黄珉珉, 李佳, 褚一鸣
doaj  

Molecular mechanism of inhibitory effect of lipoxin A4 on estrogen-induced epithelial to mesenchymal transition (EMT) in endometriosis [PDF]

open access: yes, 2016
子宫内膜异位症,简称内异症(Endometriosis,EM),是育龄妇女的常见病,它是指具有活性的子宫内膜出现在子宫腔以外所引起的一种病变。人群发病率高达10%-15%。其典型症状为不孕和疼痛,严重影响患者的生活质量和家庭和谐,尤其是高达50%的复发率,给家庭和社会带来沉重的经济负担。这一系列防治难题的根本原因在于发病机制尚不明确。解析内异症的发病机制,进而寻找新的药物靶点和安全高效的治疗方法具有重大意义。 本论文首先以临床内异症患者在位/异位子宫内膜组织及非内异症患者子宫内膜组织为研究对象 ...
吴荣锋
core  

Linking biochemical properties of particles to particle-attached and free-living bacterial community structure along the particle density gradient from freshwater to open ocean [PDF]

open access: yes, 2016
海洋颗粒有机质(particulateorganicmatter,POM)作为初级生产力的承担者,是链接生物泵和微型生物碳泵的重要桥梁,在海洋物质和能量循环中扮演重要角色。海洋颗粒附着(particle-attached,PA)细菌能够寄居在颗粒物上,通过细菌水解酶作用将POM转化成溶解有机质(dissolvedorganicmatter,DOM),在颗粒物周围形成羽流。POM在去除过程中直接为PA细菌提供底物,影响PA细菌群落组成,而颗粒物释放的小分子化合物则影响周围的浮游(free-living ...
肖伟
core   +1 more source

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