Results 51 to 60 of about 12,951 (170)

Synthesis and Characterization of Lanthanum-based Nano Catalysts for Oxidative Coupling of Methane [PDF]

open access: yes, 2015
甲烷氧化偶联(OCM)是实现甲烷直接转化制C2烃的重要途径,研发有效的催化剂,使甲烷活化温度降低,目标产物深度氧化得到抑制,是一极富挑战性的课题。纳米催化剂,因粒径小,比表面大,分散性好,表面原子配位未饱和程度高,因而具有较强的选择活化反应物分子的能力,受到了人们的普遍关注。因此,本文以镧氧化物为研究对象,从纳米催化剂的制备、改性及阴阳离子调变(掺杂)等角度出发,对催化剂的构效关系进行了研究。主要结果总结如下: 1.催化剂的分散性和酸碱性:通过于浸渍液中添加聚乙烯吡咯烷酮(PVP ...
侯玉慧
core  

Tailoring Spin States of CuNNi3 via d‐d Orbital Coupling for High Performance Water Splitting

open access: yesRare Metals, Volume 45, Issue 3, March 2026.
ABSTRACT Against the backdrop of escalating global energy crises and environmental challenges, the development of clean and sustainable hydrogen energy has become increasingly imperative. Hydrogen production via water electrolysis is widely regarded as a promising approach due to its green and efficient characteristics.
Weigao Zhong   +6 more
wiley   +1 more source

低氧环境对高原鼠兔骨骼肌HIF-1α和VEGF表达的影响

open access: yes野生动物学报, 2018
研究了在低氧应激条件下,世居高原小哺乳动物高原鼠兔(Ochotona curzoniae)和SD大鼠(Rattus norregicus)骨骼肌中HIF-1α和VEGF的蛋白质水平变化及HIF-1α和VEGF的相关性。运用双位点免疫酶测定法(ELISA)检测骨骼肌中HIF-1α和VEGF的表达水平。结果表明,在低氧暴露(6 h)条件下,高原鼠兔和SD大鼠氧化和糖酵解型肌纤维中HIF-1α和VEGF的表达水平都显著高于常氧组 ...
谢惠春 罗巧玉 陈 志 乔 枫
doaj  

Effect of Benzalkonium Chloride on Corneal Epithelial Barrier Function and Possible Mechanisms of Benzalkonium Chloride Inhibiting Corneal Endothelial Gap Junction Intercellular Communication [PDF]

open access: yes, 2015
第一部分:局部应用前列腺素类药物对兔角膜上皮细胞屏障功能的影响 目的:苯扎氯铵(BAK)是滴眼液中最常用的防腐剂之一,大量的临床研究发现,局部长期使用含BAK的眼部制剂会出现很多眼部不适症状。含BAK的前列腺素类药物是治疗开角性青光眼的一线药物,临床上患者往往需要长期使用,易导致眼睛干涩,结膜充血等等,然而其作用机制还不是非常清楚。紧密连接与粘着连接等构成了角膜上皮抵御外界病原微生物入侵的第一道生理屏障,对角膜正常生理功能的维持具有非常重要的作用 ...
张振豪
core  

Peri-operative pulse oximetry in low-income countries: a cost–effectiveness analysis [PDF]

open access: yes, 2014
Objective: To evaluate the cost–effectiveness of pulse oximetry – compared with no peri-operative monitoring – during surgery in low-income countries. Methods: We considered the use of tabletop and portable, hand-held pulse oximeters among patients of ...
Burn, Samantha L   +3 more
core   +1 more source

Multi‐Functional S‐HA/ASTA NPs Coating on Biodegradable ZE21B Alloy for Cerebrovascular Applications

open access: yesRare Metals, Volume 45, Issue 2, February 2026.
ABSTRACT Magnesium (Mg) and its alloys have attracted extensive attention of researchers in the field of cerebrovascular implants due to their good mechanical properties and biosafety. However, rapid degradation and delayed endothelialization pose challenges. To address these issues, this study introduces a multifunctional composite coating.
Aqeela Yasin   +4 more
wiley   +1 more source

Preparation and Characterization of FeOx/Rh(111) and CoOx/Rh(111) Model Catalysts [PDF]

open access: yes, 2014
多相催化剂的表面是催化反应的活性位点,表面组成、粒径和结构决定了催化剂的催化性能。真实催化剂结构复杂并且表面不均一,阻碍了表面灵敏的表征手段的运用,无法精准确定其构效关系。构建成分简单结构单一的模型催化剂表面可简化传统催化剂的复杂性,用以研究气体吸脱附、催化活性和选择性、构效关系等催化问题。本论文在超高真空环境中制备模型表面FeOx/Rh(111)和CoOx/Rh(111),应用表面科学仪器X-射线光电子能谱(XPS)和低能离子散射谱(LEIS)对模型表面进行表征,取得了如下结果: 一、在高温 ...
王文毅
core  

利用去囊导管下咽部给氧快速纠正无痛胃镜肥胖患者血氧饱和度的研究

open access: yesZhongguo shiyan zhenduanxue, 2014
目的探讨利用去囊后的气管导管(简称去囊导管)下咽部给氧,快速纠正无痛胃镜检查中肥胖患者血氧饱和度的可能性。方法选择无痛胃镜肥胖患者1274例,随机分为鼻导管组(A组)和下咽部导管组(B组),当无痛麻醉过程中血氧饱和度下降10%以上时,A组采取加大鼻导管氧流量、抬高下颌等方式纠正低氧状态,B组通过去囊导管下咽部供氧纠正低氧状态。结果 A组和B组患者出现血氧饱和度下降10%以上者分别为617例(96.86%)和598例(93.86%),两组无明显差异(P>0.05)。A组中303例(49.11 ...
刘佰纯   +6 more
doaj  

Functions of Periostin in pre-metastatic immunosuppressive niches of breast tumor metastasis [PDF]

open access: yes, 2016
在肿瘤发生发展过程中,肿瘤细胞及其相关间质细胞向肿瘤微环境中分泌大量促癌细胞因子以及趋化因子,促使骨髓来源的免疫抑制细胞(myeloid-derivedsuppressorcells,MDSCs)向远处靶器官浸润,形成免疫抑制微环境,为肿瘤细胞的转移提供有利条件,从而促进肿瘤细胞的转移。在乳腺癌肿瘤组织中,细胞外基质蛋白Periostin主要由肿瘤相关成纤维细胞分泌,并参与调控肿瘤的发生发展过程。然而,关于Periostin蛋白在MDSCs介导的转移前微环境形成中的功能尚不清楚 ...
熊珊珊
core  

Effect of two different ways of oxygen inhalation on relieving postoperative hypoxemia of patients underwent abdomen operation

open access: yesHuli yanjiu, 2005
[目的 ]探讨面罩给氧和鼻塞给氧缓解腹部手术后低氧血症的效果。 [方法 ]择期上中腹部手术病人 ,术后回病房第一时间监测血氧饱和度 (SpO2 )≤ 90 %的病人 44例 ,将其随机分为面罩组及鼻塞组 ,分别给予面罩和鼻塞给氧方式 ,观察给氧 4h、6h、8h病人血氧饱和度的变化及病人舒适度反应。 [结果 ]面罩组的氧疗效果明显优于鼻塞组 (P
王惠莹, 许琼, 蔡可莉, 钟晓珊
doaj  

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