1－十二烷基氮杂环庚烷－2－酮的合成

己内酰胺与溴代十二烷在氢氧化钾的作用下，于甲苯中进行Ｎ－烷基化反应，合成了１－十二烷基氮杂环庚烷－２－酮，收率８８％～９２％。     

Synthesis and properties of a thiophene-substituted diaza[7]helicene for application as a blue emitter in organic light-emitting diodes

Carbazole-based diaza[7]helicene substituted by thiophene groups, 2,12-dithiophene-5,15-dihexyl-5,15-diaza[7]helicene (6), was synthesised successfully and confirmed by ¹H NMR, ¹³C NMR, High Resolution Mass Spectrometry, Time of Flight Mass Spectrometry. Compound 6 exhibited good solubility and excellent thermal stability with no melting point and a high decomposition temperature of 453.64 °C. A doped device with a structure of ITO/NPB (50 nm)/CBP: 10% 6 (30 nm)/Bphen (20 nm)/Mg:Ag (150 nm)/Ag (50 nm) emitted the blue light at 460 nm with Commission Internationale de LEclairage (CIE) coordinate of (0.176, 0.26). The maximum brightness and external quantum efficiency (EQE) were 2306 cd m^?2 and 0.41%, respectively.     

ESR study of the hydrogenated nanocrystalline silicon thin films

We studied the stability and light-induced paramagnetic centers in hydrogenated nanocrystalline silicon thin films (nc-Si:H) by electron-spin-resonance (ESR) and photothermal-deflection-spectroscopy (PDS). There is no measurable change in defect density upon illumination with white light with a light intensity of 300 mW cm^?2 for 300 h. At low temperatures, upon illumination with sub-bandgap light, a light-induced ESR signal appears. This signal is similar to that in hydrogenated micro-crystalline silicon (μc-Si:H).     

Characterization of tunnel oxide passivated contact with n-type poly-Si on p-type c-Si wafer substrate

The junction properties of tunnel silicon oxide (SiO_x) passivated contact (TOPCon) with n-type poly-Si on p-type c-Si wafer are characterized using current-voltage (J-V) and capacitance-voltage (C-V) measurements. The dark J-V curves show a standard diode characteristic with a turn-on voltage of ～0.63 V, indicating a p-n junction is formed. While the C-V curve displays an irregular shape with features of 1) a slow C increase with the decrease of the magnitude of reverse bias voltage, being used to estimate the built-in potential (V_bi), 2) a significant increase at a given positive bias voltage, corresponding to the geometric capacitance crossing the ultrathin SiO_x, and 3) a sharp decrease to negative values, resulting from the charge tunneling through the SiO_x layer. The C of depleting layer deviates from the normal linear curve in the 1/C²-V plot, which is caused by the diffusion of P dopants from the n-type poly-Si into the p-type c-Si wafer as confirmed by the electrochemical capacitance-voltage measurements. However, the 1/C^2+γ-V plots with γ > 0 leads to linear curves with a proper γ and the V_bi can still be estimated. We find that the V_bi is the range of 0.75–0.85 V, increases with the increase of the doping ratio during the poly-Si fabrication process, and correlates with the passivation quality as measured by the reverse saturated current and implied open circuit voltage extracted from transient photoconductivity decay.     

Electric Field-driven Acid-base Transformation: Proton Transfer from Acid(HBr/HF) to Base(NH3/H2O)

The proton-transfer between ammonia/water and HF/HBr without and with the stimulus of external electric fields(E_ext) was investigated with the ab initio calculations. When external electric field is applied, the proton transfer occurs, resulting in ion-paired H₄N⁺X^- and H₃O⁺X^-(X=Br and F) from hydrogen-bonded complexes in view of the great changes of geometrical structures, dipole moments, frontier molecular orbitals and potential energy surfaces in the critical external electric fields(E_c) of 1.131×107 V/cm for H₃N-HBr, 1.378×108 V/cm for H₃N-HF, 9.358×107 V/cm for H₂O-HBr and 2.304×108 V/cm for H₂O-HF, respectively. Furthermore, one or three excess electrons can trigger the proton transfer from H₃N-HBr and H₃N-HF to H₄N⁺Br^- and H₄N⁺F^-, while two and four excess electrons can induce the proton transfer from H₂O-HBr and H₂O-HF to H₃O⁺Br^- and H₃O⁺F^-, respectively. Compared with that of the analogous NH₃/H₂O-HCl systems, the strength of E_c of proton transfer increases from HBr to HCl and HF for either H₃N-HX or H₂O-HX series, which is understandable by the fact that the acidity sequence is HBr>HCl>HF. And the larger of acidity of conjugated acid, the smaller of needed E_c. On the other hand, the E_c for the systems of NH₃ with a stronger basicity is generally smaller than that of H₂O systems for the same conjugated acid.     

不连续冷源布局多孔介质内热流耦合LBM数值模拟

为研究不连续冷源边界对内置发热体多孔介质方腔内传热及流动的影响，采用格子Boltzmann方法对REV尺度下多孔介质方腔内的自然对流进行计算，并研究瑞利数（Ra）、达西数（Da）、孔隙度对多孔介质方腔内传热流动的影响.发现Da对方腔内的流体流型影响很大，Da为10^-4时，多孔介质方腔内只有一个涡流，而Da为10^-2时，方腔内有两个涡流.增大Ra、Da、孔隙度可以提高冷源壁面的平均努赛尔数（Nu），增强散热效果，孔隙率对平均Nu影响程度和Da的大小有关.当冷源布置在壁面上方，壁面的平均Nu随Ra的增加剧烈变化，方腔处于高Ra条件下时，将冷源布置在边界的上方可以提高散热效果.6种布置方案中Case 6的散热效果最好.     

Preparation of phosphorus-modified PITQ-13 catalysts and their performance in 1-butene catalytic cracking

A series of phosphorus-modified PITQ-13 catalysts was prepared by wet impregnation of NH4H2PO4 solution into an HITQ-13 parent. The catalysts were characterized using XRD, N2 adsorption, MAS NMR and NH3-TPD. Their catalytic performance in 1-butene catalytic cracking was evaluated in a fixed fluidized bed reactor. The results showed that the crystallinity, surface area and pore volume of P-modified PITQ-13 catalysts decreased with the increasing amounts of P. The number of weak acid sites increased, whereas that of strong acidity decreased. The selectivity to propylene in 1-butene cracking reactions increased because of the decrease in strong acidity. The yield of propylene achieved 41.6% over PITQ-13-2 catalyst with a P content of 1.0 wt%, which was 5.1% greater than that achieved over HITQ-13 catalyst.     

Optimization and characterization of i/p buffer layer in hydrogenated nanocrystalline silicon solar cells

The effect of a-Si:H i/p buffer layer on the performance of nc-Si:H solar cells is studied systematically. The results show that for thin nc-Si:H cells, an optimized i/p buffer layer significantly reduces the dark current thus increases the open-circuit voltage. We believe that the carrier recombination at the i/p interface is one of the determining factors for the nc-Si:H cell performance, especially for cells with a thin intrinsic layer. Therefore, optimizing the i/p buffer layer is one of the key factors for achieving high efficiency nc-Si:H solar cells. This interface effect is less pronounced as the nc-Si:H intrinsic layer thickness increases, where the recombination in the bulk becomes a dominant factor. Combining the improved nc-Si:H intrinsic layer with a proper hydrogen dilution and an optimized a-Si:H i/p buffer layer, the performance of nc-Si:H single-junction and a-Si:H/a-SiGe:H/nc-Si:H triple-junction cells is significantly improved.     

翼型近尾迹流动的PIV研究

利用在线式互相关PIV系统,在低速风洞中对NACA0012翼型的近尾迹流动进行了实验研究。实验结果表明,翼型近尾迹存在有序的涡街结构,涡街在尾缘处形成后,在向下游的迁移中,会经历一个发展壮大,失稳破碎,最终演化为湍流的过程、本文分析了近尾迹流动结构、流动机制,探讨了近尾迹流动中旋涡和涡街的稳定性．本文指出在翼型尾缘处采用恰当的流动控制措施,可以改变尾流与其下游物体相互作用的形式和机制,以达到兴利除弊的目的。     

Scalable sulfonate-coated cotton fibers as facile recyclable adsorbents for the highly efficient removal of cationic dyes

Adsorbents that exhibit a high adsorption capacity and facile recyclability are considered promising materials for dye wastewater remediation. In this work, a novel sulfonate-decorated cotton fiber was fabricated as a recyclable adsorbent for the highly efficient removal of cationic dyes. Herein, poly(sodium p-styrene sulfonate-co–N-methylol acrylamide) (P(SSNa-co-NMAM)) with SSNa units as adsorption sites and NMAM units as thermal-crosslinking points was synthesized for the modification of cotton fibers. As expected, the as-obtained P(SSNa-co-NMAM)-coated cotton fibers (PCFs) presented outstanding adsorption capacities toward cationic dyes, even in the simulated effluents. The processes of cationic dye absorbing onto the PCFs were well fitted by the Langmuir isotherm model and pseudo-second-order kinetics. The thermodynamic study revealed that the adsorption reaction of the cationic dyes onto PCF was spontaneous, and the efficiency of adsorption was more desirable at higher temperatures. The maximum adsorption capacities of PCF toward methylene blue (MEB), rhodamine B (RhB), and malachite green (MG) were 3976.10, 2879.80, and 3071.55 mg/g, respectively. The dye removal mechanism was ascribed predominantly to electrostatic interactions. Moreover, the adsorption capacity of the PCFs toward cationic dyes was slightly influenced by the pH of the solutions because of the sulfonate moieties, which exhibit stability under acidic and alkaline conditions. Furthermore, the recyclability and reusability of the as-prepared PCFs were satisfactory and good mechanical properties and thermal stability were observed compared to those of pristine cotton fibers. Given the aforementioned results, the as-obtained PCFs are highly promising as ideal adsorbents for the remediation of dye-contaminated wastewater.

Graphical abstract