Vanadium species in new catalysts for the selective oxidation of methane to formaldehyde: Activation of the catalytic sites

New vanadium oxide supported on mesoporous silica catalysts for the oxidation of methane to formaldehyde were investigated by infrared and Raman spectroscopies to identify and characterize the molecular structure of the most active and selective catalytic sites. In situ and operando experiments have been conducted in order to understand the redox and hydroxylation/dehydroxylation processes of the vanadium species. (SiO)₂VO(OH) species were identified in these catalysts in reaction conditions and shown to undergo a deprotonation at 580 °C under vacuum, leading to a site giving a photoluminescence band at 550 nm attributed to reverse radiative decay from the excited triplet state:

(V⁴⁺–O⁻)^*  (V⁵⁺O²⁻). An activation mechanism of vanadium monomeric species with electrophilic oxygen species is proposed.     

电镀锡机组软熔导电辊脱锡技术研究

粘锡是电镀锡机组软熔导电辊失效的主要原因,应用化学方法脱锡是延长导电辊寿命的重要途径.开发了氢氧化钠(钾)为主要组成,并加入适量亚铅酸钠(钾)和硝酸(亚硝酸)钠配制而成脱锡剂,当脱锡剂温度为40～80℃,导电辊表面温度为40～70℃时,对粘锡导电辊具有很好的脱锡效果.粘锡导电辊脱锡后的表面粗糙度可以恢复到4.0μm以上,导电辊使用寿命提高80%,降低导电辊修复成本90%,并大幅度减少导电辊更换时间,提高电镀锡机组生产作业率.     

20.4K冷氦加温及氧箱的模拟增压试验技术

主要介绍２０．４Ｋ低温氦气经过加温后给液氧贮箱增压的试验技术。对试验设备、试验方法、试验过程及试验结果做了简要的介绍。     

Fe—Ga—O系平衡测定

在钼丝炉内氩气保护下，利用固体电解质定氧探头测定了含镓１．８７％～６．２１％范围内Ｆｅ－Ｇａ－Ｏ三元系平衡时的氧活度，通过处理得到镓在铁液中的标准溶解自由能等热力学参数与温度的关系。     

Consequences of the formation of Cooper-pairs near oxygen-deficient sites

In this investigation we consider the formation of Cooper pairs near the oxygen-deficient sites in Y-Ba-Cu-O ceramic superconductors which would give rise to an energy-dependent potential as seen by conduction charge carriers. It is shown that Cooper pairs could be formed under such conditions, resulting in a supercurrent. We use the Bogoliubov transformation technique to calculate the energy gap, the energy difference, and the transition temperature of the model superconductor using certain data obtained from previous experiments. Numerical analysis shows that the superconducting current can be explained by the presence of such oscillating Cooper pairs.     

High-temperature properties of the Bi-Sr-Ca-Cu-O system: Simultaneous occurrence of melting, oxygen desorption, and a metal-insulator transition

We have investigated the temperature dependence of the electrical transport and the thermogravimetric properties, from -200°C to +1000, of the Bi-Sr-Ca-Cu-O high-temperature superconductor. We conclude that this system has a cooperative, simultaneous-melting/oxygen desorption/metal-insulator transition that occurs near 900°C. We speculate on its nature and on its relationship to phenomena found in other high-T _c superconductors.     

Annexin 1 Is a Component of eATP-Induced Cytosolic Calcium Elevation in Arabidopsis thaliana Roots

Extracellular ATP (eATP) has long been established in animals as an important signalling molecule but this is less understood in plants. The identification of Arabidopsis thaliana DORN1 (Does Not Respond to Nucleotides) as the first plant eATP receptor has shown that it is fundamental to the elevation of cytosolic free Ca²⁺ ([Ca²⁺]_cyt) as a possible second messenger. eATP causes other downstream responses such as increase in reactive oxygen species (ROS) and nitric oxide, plus changes in gene expression. The plasma membrane Ca²⁺ influx channels involved in eATP-induced [Ca²⁺]_cyt increase remain unknown at the genetic level. Arabidopsis thaliana Annexin 1 has been found to mediate ROS-activated Ca²⁺ influx in root epidermis, consistent with its operating as a transport pathway. In this study, the loss of function Annexin 1 mutant was found to have impaired [Ca²⁺]_cyt elevation in roots in response to eATP or eADP. Additionally, this annexin was implicated in modulating eATP-induced intracellular ROS accumulation in roots as well as expression of eATP-responsive genes.     

关于超耐候性BA01—02钛白粉的研制

采用高温淬火方法制备了Ｔｃ在２７．４Ｋ至９２．４Ｋ之间的一组不同氧含量的ＰＭＰ（粉末熔融工艺）法ＹＢＣＯ超导体。通过对这些超导体样品的磁滞回线及不可逆线的研究发现，随着氧空位的增加，超导体的磁通钉扎力减小     

Reactivity study and kinetic evaluation of CuO-based oxygen carriers modified by three different ores in chemical looping with oxygen uncoupling (CLOU) process

In the chemical looping with oxygen uncoupling (CLOU) process,CuO is a promising material due to the high oxygen carrier capacity and exothermic reaction in fuel reactor but limited by the low melting point.The combustion rate of carbon is faster than the decoupling rate of oxygen carrier (OC).Hence,high tem-perature tolerance and rapid oxygen release rate of CuO modified by three different ores were investi-gated in this study.The kinetics analysis of oxygen decoupling with Cu-based oxygen carriers was also evaluated.Results showed that CuO modified by chrysolite had faster oxygen release rate than that of CuO.Limestone showed obvious positive effect on the oxidization process.The selected OCs could keep stable in at least 20 cycles,for about 1200 min.Shrinking core model (SCM) fitted well for the decoupling process in the temperature range of 1123-1223 K.Reduction rate kinetic information may aid in the development of chemical looping with oxygen uncoupling (CLOU) technologies during reactor design and process modeling.Ternary doped copper oxide with chrysolite and limestone could improve the reactivity of CuO in decoupling and coupling process and also improve the high temperature tolerance.     

多孔普鲁士蓝类似物的合成及电催化析氧性能

采用一种简单易行的共沉淀法合成了前驱体镍铁普鲁士蓝类似物NiFe-PBA（NF）,然后通过溶剂热处理获得了镍铁普鲁士蓝纳米多孔材料（NFP）。通过XRD、SEM、TEM、XPS、BET及电化学方法对所得材料进行了结构表征和析氧性能测试。结果表明,NFP相对于前驱体NF,电化学比表面积增大、催化活性位点增多,电催化析氧反应（OER）性能显著提高。在浓度1 mol/L KOH水溶液中,达到10 mA/cm2电流密度时,NFP所需过电位仅为260 mV,比NF（320 mV）前驱体低18.75%,也优于大多数已报道的非贵金属催化剂和商用贵金属催化剂,显示出良好的应用前景。