An in-situ DRIFTS study in the reaction between NO x and soot on BaAl2O4

The interactions between NO, O2 and their mixture on BaAl2O4, as well as the reaction of NOx with soot in the presence of O2, have been investigated using Diffuse Reflectance Infrared Fourier Transform Spectroscopy （DRIFTS）. NO adsorption produces only nitrites species in the absence of O2. NO2 adsorption produces nitrates species besides nitrites species. The produced nitrites will further react with O2, Osurf^-. and Olattice^2- to form nitrates. The reaction of NOx with soot begins with the reaction of nitrates with soot oxygenated complex （C（O））, which is regarded as the key and rate determining step. A reaction pathway is proposed for the catalyzed reaction of NOx with soot in the presence of O2.     

A formal synthesis of psymberin

A formal synthesis of psymberin (irciniastatin A) is presented. Notable features of the synthesis include the chemo-, regio-, and stereoselective oxidation of a 1,3-disubstituted allene, a configuration-dependent spirodiepoxide opening, the efficient syntheses of functionalized trans-2,6-disubstituted pyrans, and the union of a highly functionalized aldehyde with a pentasubstituted aryl homoenolate to give a dihydroisocumarin. [structure: see text]     

论中小学教师的人文素养及其拓展与提升

通过追溯分析,论述了导致现有教师人文素养欠缺的时代背景和社会因素。从教师人文素养的内涵及人文素养的基础性、发展性和延伸性三个层次中的诸要素出发,围绕我国中小学校教师现阶段的人文素养情况,给出拓展和提升教师人文素养的途径、方式和方法。     

Reconstruction of core-shell dispersed particles in impact polypropylene copolymer during extrusion

We reported an approach to reconstruct the complex phase morphology of impact polypropylene copolymer(IPC) with core-shell dispersed particles and to optimize its toughness in approximate shear condition. The molten-state annealing results indicate that the phase structure with core-shell dispersed particles is unstable and could be completely destroyed by static annealing, resulting in the degradation of impact strength. By using a co-rotating twin screw extruder, we found that the dispersed particle with core-shell structure could be rebuilt in appropriate condition with the recovery of excellent impact strength due to both the huge interfacial tension during solidification and the great difference in viscosity of components. Results reveal that almost all the extruded IPCs show the impact strength 60%-90% higher than that of annealed IPCs at room temperature. And the twice-extruded IPC shows the highest impact strength, 446% higher than that of IPC annealed for 30 min. As for low temperature tests, the impact strength of extruded IPCs also increases by 33%-58%. According to adjusting the processing conditions including extrusion speed, extrusion frequency and temperature, an optimization of toughness was well established.     

Glacier changes during the last forty years in the Tarim Interior River basin, northwest China

By comparing digitized glacier outlines from the Chinese Glacier Inventory (CGI) during the 1960s–1970s and Landsat Enhance Thematic Mapper (ETM+) images from 1999 to 2001, we investigated changes for about 7665 alpine glaciers among 11665 glaciers in seven sub-basins of the Tarim Interior River basin (TIRB). The results showed that the total glacier area was reduced by 3.3% from the 1960s/ 1970s to 1999/2001 and area losses for 1–5 km2 glaciers accounted for 48.3% of the total glacier area loss in the TIRB. However, the glacier area reductions varied from 0.7% to 7.9% among the seven sub-basins of the TIRB during the study period. The glacier area changing with altitude showed that the maximum contribution of area shrinkage occurred at 4900–5400 m. Data from 25 meteorological stations in the TIRB showed increases in both the annual mean air temperature and annual precipitation during 1960–2000. This indicates that the glacier shrinkage in the TIRB over the last 40 years was largely due to regional climate warming that enhanced glacier ablation and overcame the effects of increased precipitation on the glacier mass balance.     

Role Assignment and Cooperation of Ontology and Object-Oriented Principle in Construction of Digital Product Model

Powerful expressive ability of semantic information, to be easily computed and flexibility are basic features of digital product model (DPM). Using ontology and object-oriented principle (OOP) together to cope with problems in modeling is brought forward in this paper. The two are widely used and do well in modeling, but they each alone cannot cope with all issues and new challenges. Three basic requests are pointed out in DPM modeling. Status, problems, and root of current non-semantic and semantic models are introduced. Ontology, OOP, and their difference are introduced. It is found that the two are entirely complementary with each other. How to assign the roles and to cooperate for the two in coping with the three basic issues in DPM modeling are explained in detail.     

缩比地下化学爆炸气体泄漏规律研究

针对气体通过均匀多孔介质、非均匀多孔介质和贯通裂缝泄漏三种机制,研究地下爆炸缩比实验气体泄漏时间和份额的规律.结果显示,对于相同介质中的缩比化学爆炸实验,气体泄漏时间与药量的三分之二次方成正比,不同药量实验的最终泄漏份额基本一致.实验室缩比化学爆炸实验气体泄漏时间关系的监测结果与理论分析基本一致.     

Speckle Noise Suppressing Based on a Generalized Parallel Weighted-Average Multidirectional Morphological Filtering Algorithm

1 IntroductionThe coherent-imaging systems, such as LR(Laser Radar) and SAR(SyntheticAPerture Radar), generate images by coherent processing of the scattering echOsignals, so they are highly susceptible to speckle not,.Lll. The presence of speckle noise' in the images reduces the resolution and the tenet-explaining ability of the images.Thus it brings about an impact on the applications of the images and the detect~abilityof LR and SAR. However, removing speckle noise is one of the mos…     

电位滴定法研究多胺铕铽络合物稳定性及其对磷酸二酯键水解断裂

用电位滴定法研究了24元大环多胺(BDBPH)-Eu(Ⅲ)和BDBPH-Tb(Ⅲ)溶液中络合物的稳定性和物种分布,分析了不同pH条件下各物种的存在形式及变化趋势。发现当3个质子被中和后BDBPH才与稀土离子发生配位,分别形成质子化和脱质子化的比较稳定的单核和双核络合物。BDBPH与Tb(Ⅲ)能够形成单羟基、双羟基和三羟基配位的双核络合物。选择BDBPH-Tb络合物体系(1∶2)研究对模型化合物-二(对硝基苯酚)磷酸酯(BNPP)的催化水解作用,得到了其二级反应速率常数(kBNPP=2.3×10-3((mol/L)-1.s-1)和络合物体系的有效物种(L-Tb2-OH),其催化机理可能是Lew is酸碱催化机理,即络合物中双金属和配位羟基分别进攻磷酯基团中的O和P,加速了原有P O键的断裂。研究结果为进一步模拟核酸酶对DNA或RNA的水解断裂提供了重要资料。     

介孔Ce-MCM-48的合成及其可见光催化性能研究

分别利用十六烷基三甲基溴化铵(CTAB)、正硅酸乙酯(TEOS)为模板剂和硅源,合成了高度有序的MCM-48材料。通过浸渍法制备了Ce含量不同的MCM-48(Ce-MCM-48s)材料。采用TG-DTA、小角XRD、N2吸-脱附、FT-IR、TEM、XPS和UV-vis等对Ce-MCM-48s进行了表征。XRD、N2吸-脱附和TEM证明Ce-MCM-48s具有与MCM-48相似的三维螺旋立体结构;FT-IR和XPS表明MCM-48孔道及其表面已被Ce氧化物所覆盖。可见光催化降解罗丹明B的实验证明,10%Ce-MCM-48的催化降解效率好于纯CeO2,商用TiO2(P125),5%Ce-MCM-48和15%Ce-MCM-48的。