“测定空气中氧气含量”实验的改进

针对沪教版九年级化学教材中“测定空气中氧气含量”实验存在的不足,在文献研究的基础上设计和优化实验,得到一种利用铁粉吸氧腐蚀原理和连通器装置的改进方案。改进方案具有原料廉价易得、绿色环保、装置简约、操作简便、现象明显、动态可视、科学高效、安全可靠的优点。     

梅猷测定空气组成实验赏析

详细介绍并分析了梅猷测定空气组成实验：利用铁与稀硝酸反应制备出一氧化氮，并将一氧化氮收集在倒置于水面的烧瓶中，使其与瓶中的氧气和水反应，从而测定出空气中氧气的含量。     

"探究空气中氧气的体积分数"教学设计和反思

现行各种版本的《义务教育课程标准实验教科书:化学》中均安排了内容相似的空气课题,本课时内容就选自空气的第一部分——测量空气中氧气的体积分数。1设计思路《全日制义务教育化学课程标准(实验稿)》明确要求学生实验探究空气中氧气的体积分数,因此在进行空气的教学时,将第一部分测量空气中氧     

邻苯三酚法测定空气中氧气的含量

按照教材中用燃烧红磷除去氧气的方法测定空气中氧气的含量,存在实验现象不明显和实验数据不严谨的问题;采用邻苯三酚法改进空气中氧气含量测定实验,操作更为简单,实验现象更明显,实验数据严谨,宜作为演示实验在教学中推广。     

利用手持技术与T形玻璃管探究钠与空气中的氧气反应*

针对钠与氧气反应教学中存在的不足,引入手持技术数字化创新实验,自主设计创新反应装置T形玻璃管以定量探究钠与氧气反应。本研究利用氧气传感器,通过测定密闭体系内氧气含量的变化,帮助学生基于四重表征模型、从定性和定量的角度认识钠与空气中的氧气在室温和加热条件下反应的区别;借助氧气、二氧化碳、湿度等3种传感器从定量的角度探究空气中的二氧化碳与水蒸气对钠的影响,形成对钠与氧气反应的科学认知。     

气相色谱法测量空气中的黄樟素

用黄樟油作原料合成其它产品,生产现场空气中含大量的黄樟素。黄樟素是一种致癌物。为减少环境污染,保障人体健康,需经常测量现场空气中黄樟素含量,以控制出排放。目前,未见国内有关现场空气中黄樟素测量的报道。为此,我们选用气相色谱法进行测量的研究,对分离的工...     

不同常压流化床煤气化方案的模型预测 Ⅱ. 模型预测及分析

利用已建立的流化床煤气化模型系统地研究了不同气化方案下的流化床煤气化性能，包括空气气化、空气/蒸气气化、空气/二氧化碳气化、氧气/水蒸气气化、氧气/二氧化碳气化5个气化方案，结果表明：空气/水蒸气和氧气/水蒸气方案具有较优的气化效率和较高的煤气品质，氧气/蒸气气化方案在煤气组分、气化效率和热效率等方面比空气/蒸气气化方案更具优势。     

利用化学史促进探究教学的案例研究

通过“空气中氧气含量的测定”、“原子的构成”和“水的组成”3个教学案例,介绍了利用化学史料促进探究教学的研究。     

白磷和红磷燃烧条件探究及空气中氧气含量测定的组合实验

用白磷和红磷在探究燃烧的条件,同时测定空气中氧气的含量,将这两个实验有机地结合在一起进行,既避免了产生的P2O5白烟污染空气,又简化了实验操作,而且实验现象明显,成功率高,特别适合用作在教师指导下的学生探究实验。     

氧气氛中紫外光辐照官能化HDPE的结构与性能研究

采用FT－IR，XPS，WAXD，DXC，凝胶和表面自由能力分析，研究了氧化氛中紫外辐照官能化高密度聚乙烯（HDPE）的化学结构、晶体结构和表面自由能的变化。与空气相比，在氧气氛中紫外辐照HDPE能提高C－O，C（＝O）O和C＝O等含氧基团的引入速度，同时又能降低HDPE中的凝胶含量，在空气和氧气氛中紫外辐照后，HDPE的晶型没有发生变化，仍为正交晶系；HDPE的晶胞参数a,b,c以及（110），（200），（020），（011），（111）等晶面间距基本保持不变；HDPE的熔融温度下降，但熔融热焓升高，结晶度增大，表面自由能增大，且在氧气氛中辐照HDPE的变化幅度较大。     

SrTi0.9M0.1O3-δ钙钛矿型氧化物催化剂甲烷氧化偶联反应性能的研究

The structure and catalytic properties of SrTi_0.9M_0.1O_3-δ (M=Mg，Al， Zr) perovskite-type catalysts for ox-idative coupling of methane (OCM) have been studied by using X-ray diffraction (XRD)，X-ray photoelectron spectroscopy (XPS) and temperature-programmed desorption of oxygen(O₂-TPD) methods. It has been shown that doping the cations of lower valence (e.g. Mg²⁺， Al³⁺) to the B site of SrTi_0.9M_0.1O_3-δ perovskite-type catalysts results in the higher content of adsorbed oxygen species on the surface of catalysts and thus higher C₂-selectivity for OCM reaction. It is suggested that the oxygen vacancies of SrTi_0.9M_0.1O_3-δ (M=Mg， Al， Zr) perovskite-type catalysts are the sites responsible for oxygen activation， and the adsorbed oxygen species on the surface of SrTi_0.9M_0.1O_3-δ catalysts are the main active species for OCM reaction.     

SrTi1-xMgxO3-δ钙钛矿型氧化物催化剂甲烷氧化偶联反应性能的研究

The structure and catalytic properties of SrTi_1-xMg_xO_3-δ perovskite-type catalysts for oxidative coupling of methane (OCM) have been studied by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Temperature-programmed desorption (O₂-TPD) methods. It has been shown that doping Mg²⁺ cations to the B site of SrTi_1-xMg_xO_3-δ perovskite-type catalysts results in the formation of oxygen vacancies in the lattices of oxide cata-lysts. With increasing the amount of Mg²⁺ doped in the B site of SrTi_1-xMg_xO_3-δ, methane conversion and C₂ selectivity first increase and then decrease remarkably. The SrTi_1-xMg_xO_3-δ catalyst with x=0.1 has the highest methane conversion and C₂ yield. It is suggested that the oxygen vacancies produced by Mg²⁺ cations doping are the sites responsible for oxygen activation, and the adsorbed oxygen species on the surface of SrTi_1-xMg_xO_3-δ catalysts are the main active species for OCM reaction. However, the over high content of the adsorbed oxygen species on the surface results in the complete oxidation of methane. Introducing water steam into feedstock can improve the catalytic properties of SrTi_1-xMg_xO_3-δ perovskite-type catalysts for OCM reaction at lower temperature. The SrTi_0.9Mg_0.1O_3-δ catalyst has the methane conversion of 28.0 % with C₂ hydrocarbons selectivity of 36.8 % under reaction temperature of 550 ℃.     

唇周紫绀新生儿与正常新生儿血氧饱和度对比分析

为了探讨新生儿出现唇周紫绀与缺氧关系，选择了两组新生儿（唇周紫绀组及正常组各101例），进行了血氧饱和度检测，结果表明无论是周紫绀或是正常新生儿，只要其呼吸频率＜600bpm，血氧饱和度均大于等于94％，将这两组新生儿血氧饱和度进行对比检测，证实两组均数无显著性差异（P＞0．05），提示仅有唇周紫绀不能作为缺氧依据。     

有机过氧化物中过氧键的建立(引入)方法

有机过氧化物目前已发展成非常重要的一类抗疟药物. 形成/引入过氧键是合成有机过氧化物的关键步骤和难点所在. 对合成有机过氧化物时常见的建立或引入过氧键的方法、各方法的适用范围及优劣所在作了简要的综述.     

活性炭表面性质对氧气扩散电极电催化性能的影响

 分别采用硝酸和空气氧化处理制得具有不同表面性质的粉末活性炭,并以此为催化层材料制成炭基氧气扩散电极,测定了不同电极的极化曲线和电化学阻抗谱. N2物理吸附和He程序升温脱附(He-TPD)研究表明,硝酸处理对活性炭孔结构的影响较小,但可使其表面含氧基团明显增加; 而空气氧化处理则会导致活性炭的中孔面积和孔容显著增大,但对表面含氧基团的影响较小. 极化曲线和电化学阻抗谱研究发现,当活性炭的孔结构相近时,电极的催化性能随着表面含氧基团的增多而急剧下降; 当活性炭表面含氧基团的量相近时,中孔孔容增大将导致电极催化性能的恶化. 与活性炭表面含氧基团相比,孔结构对氧气扩散电极的电化学性能具有更显著的影响.     

负载型氧电极PtRuIr/TiC催化剂的制备、结构及CV研究

以TiC纳米粉作载体,超声波分散?共还原沉积方法制备以Pt、Ru和Ir为活性组分的负载型催化剂PtRuIr/TiC.BET比表面积、扫描电子显微镜(SEM)、X光衍射(XRD)及循环伏安(CV)等测试表明:该负载型催化剂活性组分Pt、Ru、Ir微晶(组成2.6%Pt,1.3%Ru,16%Ir和80%TiC,by mass)在载体TiC上趋于无定型化结构,主要分散在载体的外表面上,其析氧性能约是相同成分无负载催化剂的3倍,经过120次CV扫描,PtRuIr/TiC在电解质溶液中几乎不溶解.实验证实,这一电极具有良好的电化学催化性能和稳定性.     

利用数字化实验研究“油封”对水中溶解氧的影响

通过光学溶解氧传感器分别测定花生油和煤油以“油封”方式对水中溶解氧的影响,证实了植物油和矿物油“油封”都不能完全隔绝氧气,但能明显减小氧的溶解速率,在一定时间内使水或溶液中溶解氧处于低浓度状态,且植物油比矿物油更有利于维持水样的贫氧状态。     

适宜氧空位诱导α-MnO2高效催化消除碳烟研究

柴油机排放的碳烟颗粒对人类和自然产生了严重的威胁,开发高活性低成本的碳烟燃烧催化剂是解决这一问题的关键。本文采用不同煅烧气氛（空气、真空和氮气）成功制备了含有不同浓度氧空位的α-MnO2催化剂（记为M-Air-500,M-Va-500,M-N-500,M-N-450）。M-Va-500和M-N-500催化剂在500 ℃煅烧会失去过多晶格氧,导致晶相结构发生改变,出现Mn3O4相,这与XRD和HRTEM结果一致。XPS和Soot-TPR的结果说明,适量的表面氧空位能够吸附并活化氧气分子,催化剂表面的化学吸附氧提高了催化剂的催化性能。H2-TPR结果说明适量的氧空位能够加快晶格氧的迁移,提高可移动氧物种丰度,增强催化剂的氧化能力。结合催化活性测试结果可以得出：在保持α-MnO2晶相结构的前提下,氧空位越多,催化剂表面的化学吸附氧越多,催化活性越好。     

High purity oxygen production with a polymer electrolyte membrane electrolyser

Oxygen is required for treatment of patients in hospitals and at home, in industrial processes and for fuel combustion. Most commonly oxygen is produced by cryogenic or pressure swing adsorption routes. Other techniques include oxygen-ion conducting ceramic membranes, polymer membranes and chemical processes used mainly in civil aviation to reduce the condition of hypoxia at high altitudes. Water electrolysis is used mainly for the production of hydrogen with oxygen as a by-product. In order to use this system only for oxygen production, hydrogen must be utilised and disposed off safely. This, however, is not practical in many instances where there is no use for hydrogen and it poses an explosion hazard. In this paper, an electrolyser system based on polymer electrolyte membrane is described in which hydrogen produced on one side of the electrochemical cell is consumed by combining it with atmospheric oxygen, through operating the cell in a carefully configured fuel cell mode. This reduces the power consumed in the electrolysis operation by more than 35% and eliminates hydrogen in exit gases. Oxygen generated is of high quality and can be used for human consumption (portable and plug-in home care oxygen therapy devices, in hospitals, defence or aerospace requirements) and for many other industrial applications.     

Taming of Singlet Oxygen: Towards Artificial Oxygen Carriers Based on 1,4-Dialkylnaphthalenes

Naphthalene endoperoxides are known as convenient sources of singlet oxygen (O₂, ¹Δ_g), which is the major product of endoperoxide cycloreversion reaction. However, their potential as carriers of ground-state molecular oxygen (O₂, ³Σ_g) similar to artificial oxygen carriers remains largely unexplored. This is due to the extreme reactivity and cytotoxic effects of the released singlet oxygen. We now report that a compound with a bimodular design, which incorporates an endoperoxide and an efficient physical quencher of singlet oxygen, 1,4-diazabicyclo[2.2.2]octane (DABCO), produces exclusively ground-state molecular oxygen. This result, coupled with the fact that oxygen release rates from endoperoxides are highly amenable to fine-tuning in a very broad range, and open to targeting by ligand attachment, raises the potential of these compounds far above any comparable chemical, or even biochemical sources. In cell culture experiments, we showed that the addition of the endoperoxide-quencher conjugate can enhance and sustain cell proliferation.