Improving the photocatalytic activity of graphitic carbon nitride by thermal treatment in a high-pressure hydrogen atmosphere

Extending visible light absorption range and suppressing the recombination of photogenerated charge carriers are always important topics in developing efficient solar-driven photocatalysts. In this study, the thermal treatment process at 400 °C in a high-pressure hydrogen atmosphere was applied to modify graphitic carbon nitride. Compared to the normal atmospheric hydrogen treatment process, this process has the merit of producing nitrogen deficient graphitic carbon nitride in high-yield. The optimal photocatalytic activity of modified graphitic carbon nitride was demonstrated by controlling the treatment duration in the hydrogen atmosphere.The changes in the crystal structure, microstructure and optical properties of carbon nitrides were investigated by several characterizations. The relationship between the photocatalytic activity and structures of graphitic carbon nitride was preliminarily established. The results obtained in this study could provide some new ways of improving the activity of graphitic carbon nitride based photocatalyst.     

产业结构调整和碳排放量耦合分析——以上海为例

为准确把握产业结构调整和碳排放量的动态关系,通过构建灰色系统理论模型,选取上海市2001—2011年度碳排放量和三次产业的产值,运用灰色关联度的研究方法,具体分析了产业结构调整和碳排放量之间的关联关系.首先计算出上海市2001—2011年的碳排放量,然后结合这11年的三次产业产值,运用灰色关联度分析法分析了两者之间的关联关系.结果表明,上海第三产业和碳排放量的关联度最大,第一产业和碳排放量的关联度最小.此外,结合能耗强度的相关研究成果对结论进行分析,分别从政府、企业和社会的角度对上海市发展低碳经济提出了建议.     

原位聚合法制备高导电石墨烯-碳纳米管/聚酰亚胺柔性复合膜

用简单绿色的方法制备三明治结构的石墨烯-碳纳米管纳米复合物(Gr-CNTs),并以该复合物作为填料,通过原位聚合法制备石墨烯-碳纳米管/聚酰亚胺(Gr-CNTs/Polyimide(PI))复合膜.与CNTs/PI相比,在聚酰亚胺中掺杂少量的Gr-CNTs(w≤10%)可明显提高PI的导电能力.而且这种复合材料的导电能力可以通过控制PI基底中填料的含量加以调控.该新型复合材料有望大范围应用于电子、太阳能电池以及生物传感器等领域.     

Modeling decarburization kinetics of grain-oriented silicon steel

A mathematic model has been presented to predict the decarburization kinetics of grain-oriented silicon steel sheet in the gas mixture of N2–H2–H2O during annealing.This model is based on the carbon flux balance between the oxidation reaction at the surface and the carbon diffusion inside the steel sheet.It can be numerically solved to quantify the influences of annealing temperature and atmosphere on decarburization kinetics when the boundary conditions are properly determined.In case that a humid gas mixture is employed during annealing,the most influential process parameter is temperature rather than compositions of the gas mixture,because the diffusion of carbon in ferrite is the rate-limiting step.Therefore,a higher temperature is required for the efficient decarburization of the thicker silicon steel sheet using the industrial continuous annealing production line.     

Effect of heating rate on the electrochemical performance of MnO X @CNF nanocomposites as supercapacitor electrodes

Carbon nanofibers （CNFs） and MnOjc@CNF nanocomposites （MCNFs） are fabricated by electrospin- ning and investigated as free-standing electrodes for sup- ercapacitor. This work presents the effect of heating rate during carbonization on the electrochemical behavior of the as-prepared MCNFs electrodes in 6 mol/L KOH elec-trolyte. Results show that the MCNFs electrodes carbon- ized by relatively slower heating rate exhibit higher specific capacitance. The electronic conductivity of the slow heated MCNFs electrodes is better than that of the fast heated electrodes due to the better crystallinity of the MnOx nanoparticles and the graphitic carbon layers forming on the surface of the Mn-loaded CNFs. These MCNFs electrodes demonstrate elevated rate capability and improved cycling performance without adding any polymer binder or electronic conductor.     

Mechanical properties of carbonfi ber/cellulose composite papers modified by hot-melting fibers

Carbon fiber(CF)/cellulose(CLS) composite papers were prepared by papermaking techniques and hot-melting fibers were used for modification. The mechanical properties of the obtained composite papers with different CF,CLS and hot-melting fiber ratios were studied and further discussed. It is observed that,for both CF/CLS composite papers and those modified by hot-melting fibers,the normal stress firstly increases and then declines with the addition of carbon fibers. The results also show that with the addition of hot-melting fibers,the modified papers exhibit enhanced mechanical performance compared to CF/CLS composite papers. Through SEM characterization,it is confirmed that the improvement of mechanical properties attributes to the reinforcement of adhesive binding at the fiber overlap nodes. Also,through four-probe method,the resistivity and the electrical performance of the modified and unmodified papers were characterized and the result shows that the hot-melting fiber modification brings no harm to the electrical properties.     

论冀中地区O、C—P凝析气藏的形成条件

据凝析油轻烃组成、甲烷及其同系物碳同位素组成、天然气与源岩吸附气指纹时比、双环倍半萜组合特征及地质结构的综合分析,查明O、C—P大多数提析气藏的油气主要来源于石炭—二叠系煤系腐植型有机质,混入了部分下第三系的油气。对石炭—二叠系成烃特点的分析表明,R。=0.6%～1.3%,以成气为主,生油为辅,原始油气比一般大于1OOCm3/t。成熟期的石炭—二叠系有机质的成烃特点和具备油气富集的良好地质条件是O、C—P凝析气藏形成的基本条件。     

具有时滞的中立型非线性控制系统的镇定与控制问题

讨论了具有滞后的中立型定常非线性控制系统的镇定与次优控制问题,利用有关方法讨论了这类控制系统的镇定理论方面的有关问题,并且也得到了该系统的滞后量及线性项范围的估计公式     

氢分子吸附碳纳米管场发射性质的密度泛函理论研究

使用第一原理密度泛函理论方法,对吸附氢分子的开口(5,5)单壁碳纳米管在有电场和无电场情况下的性质进行研究。研究结果表明在有电场发射条件下,吸附氢分子后的结构更加稳定。氢分子吸附后,费米能级处的局域态密度增加。     

CeO2/CNTs复合光催化剂的制备及其对抗生素废水光催化降解研究

以多壁碳纳米管(MWCNTs)为载体,硝酸锶铵为锶源,采用水热法制备CeO2/CNTs复合管光催化剂．采用场发射扫描电子显微镜(FE．SEM)对碳纳米管负载CeO2前后的形貌进行了的表征;以阿莫西林溶液的降解为目标反应,考察了催化剂的紫外光、可见光(A>420 nm)催化活性．结果表明：所制备的催化剂基本保持了原始MWCNTs的纤维状形貌,二氧化锶在MWCNTs表面分布均匀,MWCNTs增强了污染物在催化剂表面的吸附,提高了对光的吸收和利用,因此所制备的CeO2／MWCNTs复合光催化剂表现出较高的光催化活性．