Synthesis and Biological Activity of Organothiophosphoryl Polyoxotungstates

Organothiophosphoryl polyoxotungstates R∋XW∞∞O∋∃/- , R∋ P∋W∞,O∞/-, R∋PW∃O∋ Δ-(X = P, Si, Ge, B or Ga; R = PhP(S), C6H11P(S)) have been prepared from lacunary polyoxoanions and PhP(S). The products were characterized by elemental analysis, IR, and NMR spectroscopy. According to spectroscopic observations, the hybrid anions consist of a lacunary anion framework on which are grafted two equivalent or groups through P-O-W bridges. Some of the title compounds showed the antigerm activity

Leaf photosynthetic function duration during yield formation of large-spike wheat in rainfed cropping systems

Improving photosynthetic capacity significantly affects the yield of wheat (Triticum aestivum L.) in rainfed regions. In this study, the physiological characteristics of eight large-spike wheat lines were compared with a multiple-spike cultivar as a control (CK) in a field over two consecutive seasons: 2010–2012. The tillering peak was 7–21 d after returning green for line 2040, the average rate of decline of relative water content was slower, and the average duration time of photosynthetic rate was longer than CK in vitro. There was a strong linear and positive correlation between photosynthetic rate and root activity at jointing, flowering, and grain-filling stages. In addition, average yields were higher in large-spike lines than CK (multiple-spike cultivar). The results suggest that large-spike lines might have greater water retaining capacity during yield formation under rainfed conditions

PARAMETER OPTIMIZATION OF DRILL PIPE FOR SPIRAL DRILLING MACHINE BASED ON FINITE ELEMENT METHOD

In order to improve the strength and life of the spiral drilling machine,and reduce the weight of the drill pipe,it took the spiral drill pipe of the spiral drilling machine as the research object. On the condition of meeting the strength requirement,it selected the weight of the drill pipe to be the lightest as the optimization goal. The solid optimization model was established in the software of Pro/E. The strength analysis was proceeded in the software of ANSYS Workbench based on finite element method,as the result it selected the thickness of the drill pipe and blade,height,helix angle as the optimizing parameters by observing the stress nephogram to optimize the structure parameters of the drill pipe. The result indicates that the strength of the spiral drilling machine has improved obviously,the stress is reduced by 15. 8% and the weight is reduced by6. 4%. The life of the drill pipe has been extended

Rod-like Cellulose Regenerated by Bottom-Up Assembly in Natural Rubber Latex and Its Reinforcement

As a renewable biomass material, nano-cellulose has been investigated as a reinforcing filler in rubber composites but has seen little success because of its strong inclination towards aggregating. Here, a bottom-up self-assembly approach was proposed by regenerating cellulose crystals from a mixture of cellulose solution and natural rubber (NR) latex. Different co-coagulants of both cellulose solution and natural rubber latex were added to break the dissolution equilibrium and in-situ regenerate cellulose in the NR matrix. The SEM images showed that the sizes and morphologies of regenerated cellulose (RC) varied greatly with the addition of different co-coagulants. Only when a 5 wt% acetic acid aqueous solution was used, the RC particles showed an ideal rod-like structure with small sizes of about 100 nm in diameter and 1.0 μm in length. The tensile test showed that rod-like RC (RRC)-endowed NR vulcanizates with pronounced reinforcement had a drastic upturn in stress after stretching to 200% strain. The results of XRD and the Mullins effect showed that this drastic upturn in stress was mainly attributed to the formation of rigid RRC-RRC networks during stretching instead of the strain-induced crystallization of NR. This bottom-up approach provided a simple way to ensure the effective utilization of cellulosic materials in the rubber industry

Soil organic carbon and nitrogen storage under a wheat (Triticum aestivum L.)—maize (Zea mays L.) cropping system in northern China was modified by nitrogen application rates

Field cultivation practices have changing the carbon and nitrogen cycles in farmland ecosystem, soil organic carbon (SOC) and total nitrogen (TN) were the important parameters in maintaining soil quality and increasing agricultural productivity, however, N application’s effects on the SOC and TN storage capacity under intensive wheat-maize cropping system remain unclear. Therefore, we investigated the characteristics and relationships of SOC and TN for wheat-maize cropping system under nitrogen treatments. In doing so, continuous applications of four nitrogen application rates were examined: 0, 180, 240 and 300 kg ha−1 (N0, N180, N240 and N300, respectively). Wheat yields under N180 and N240 were significantly higher than that under N300, while the maize yields under N180, N240 and N300 were significantly higher than that under N0 by 79.79, 85.23 and 86.85%, respectively; the TN content and storage were significantly higher under N240 than that under other N levels in 40–60 cm soil layer after wheat growing season; the SOC content and storage under N180 and N240 were significant higher than that under N300 in 20–40 cm after maize growing season. The correlations between SOC and TN contents (or storage) were stronger after wheat planting than maize planting. These findings provide a basis for further studies on the effect of long-term N application on SOC and TN storage, crop quality and nitrogen use efficiency under wheat-maize cropping systems

PARAMETER OPTIMIZATION OF SPIRAL DRILL PIPE FOR ANCHOR RECYCLING EQUIPMENT BASED ON PARTICLE SWARM OPTIMIZATION ALGORITHM

In order to improve the drilling efficiency and reduce the weight of the anchor recycling equipment,it took spiral drill pipe of the anchor recycling equipment as the research object,by selecting the inner and outer diameter of the drill pipe,blade thickness,pitch,helix angle,speed,blade number and blade height as the optimizing parameters. It chosen the highest efficiency in transport,the lightest in weight and the highest rate in secondary crushing as the ideal goal of the drill pipe optimization,the result indicates that the drilling efficiency is increased by 31. 4%,the weight is reduced by 12. 7% and the secondary crushing rate is increased by 48. 7% based on particle swarm optimization. The efficiency of the recovering has been improved,and the wear-resisting degree and intensity of the spiral pipe have been enhanced

Activating Mn3O4 by Morphology Tailoring for Oxygen Reduction Reaction

Oxygen reduction reaction (ORR) is becoming increasingly important with the development of fuel cells and metal-air batteries. Manganese oxides have been one of the focuses of recent research for Pt-alternative ORR catalysts. However, the structure-activity relationships of manganese oxides have not been well studied or understood. In the present work, we report a new finding that there is a strong dependence of the ORR activity of Mn3O4 on its morphology. By adopting different solvents in the wet-chemical synthesis, we are able to tailor the morphology of Mn3O4 from nanoparticles (NP-L, 12.5 nm and NP-S, 5.95 nm) to nanorods (NR, exposure of Mn3O4 (101)) and nanoflake (NF, exposure of Mn3O4 (001)). Surprisingly, surface-specific activity of NF toward the ORR was found to be one order of magnitude higher than NP-L. The morphology-activity relationships of Mn3O4 were further studied through a combination of electrochemical experiments and density functional theory (DFT) calculations. It was discovered that the formation of *OOH, concomitant with the first electron transfer, is the potential determining step, which is thermo-dynamically more facile on Mn3O4 (001) than (101) plane. The underlying mechanism could be ascribed to the strong interaction between O-2 and Mn3O4 (001) surface as indicated by the DFT calculations. The study enlarges our understanding of Mn3O4 catalysis and provides clues for rational design of highly efficient transitional metal oxide electrocatalysts for the ORR. (C) 2016 Published by Elsevier Ltd

afenccatalystwithhighlydispersedironincarbonforoxygenreductionreactionanditsapplicationindirectmethanolfuelcells

氧还原反应（ORR）是燃料电池和金属空气电池等洁净发电装置中阴极的主要反应,该反应动力学过程慢,电化学极化严重. Pt基电催化剂具有较好的ORR活性,然而Pt资源有限、价格昂贵,研制高活性、低成本的代Pt电催化剂意义重大.经过几十年的探索,研究者发现将含有C, N和Fe等元素的前体进行高温热处理得到的Fe-N-C电催化剂对ORR具有良好的活性,然而在高温热解过程中Fe容易发生聚集而形成大块颗粒,导致Fe的利用率不高,影响了电催化剂的ORR活性. 本文分别以聚吡咯和乙二胺四乙酸二钠（EDTA-2Na）为C和N的前驱体,利用高温热解形成的富含微孔的碳材料对铁前体的吸附及锚定作用,获得了一种Fe高度分散的Fe-N-C电催化剂.采用物理吸脱附技术、高分辨透射电镜（HRTEM）和扫描电镜对Fe-N-C及其制备过程中相关电催化剂的孔结构及表面形貌进行了表征.结果表明,在第一步热解过程中, EDTA-2Na的Na对碳材料起到了活化作用,形成富含微孔的N掺杂碳材料（N-C-1）,其BET比表面积达到1227 m2/g,孔径约1.1 nm.在第二步热解过程中, N-C-1有效地抑制了Fe的聚集,产物Fe-N-C中的Fe元素均匀地分布在碳材料中,其比表面积高达1501 m2/g. 电化学测试结果表明,在碱性介质（0.1 mol/L NaOH）中, Fe-N-C电催化剂对ORR具有良好的催化活性, ORR起始电位（Eo）为1.08 V （vs. RHE）,半波电位（E1/2）0.88 V,电子转移数n接近4, H2O2产率〈3%,与商品20%Pt/C（Johnson Matthey）接近.电化学加速老化测试结果表明, Fe-N-C的E1/2未发生明显变化,而Pt的负移45 mV,表明Fe-N-C具有很好的稳定性；在酸性介质（0.1 mol/L HClO4）中, Fe-N-C的Eo为0.85 V, E1/2为0.75 V,其E1/2比Pt/C负移约0.15 V,表明在酸性介质中Fe-N-C对ORR的催化活性还有待提高.采用TEM、X射线衍射、X射线光电子能谱以及穆斯堡尔谱等方法研究了电催化剂构效关系.结果表明, Fe-N-C较好的ORR活性主要来自于高分散的Fe-N4结构,此外, N（吡啶N和石墨N）掺杂的C也对反应具有一定的催化活性. 与Pt/C相比, Fe-N-C电催化剂具有很好的耐甲醇性能.本文对比了Fe-N-C和Pt/C作为阴极催化剂的直接醇类燃料电池（DMFC）性能,采用质子交换膜的DMFC最大功率密度分别为47（Fe-N-C）和79 mW/cm2（Pt/C）,而采用碱性电解质膜的则分别为33（Fe-N-C）和8 mW/cm2（Pt/C）.结合半电池结果表明, Fe-N-C电催化剂在碱性介质中具有比Pt更为优秀的催化活性和稳定性,有望用作DMFC阴极代Pt催化剂