Novel Red Phosphorescent Polymers Bearing Both Ambipolar and Functionalized IrIII Phosphorescent Moieties for Highly Efficient Organic Light‐Emitting Diodes

A series of novel red phosphorescent polymers is successfully developed through Suzuki cross‐coupling among ambipolar units, functionalized Ir^III phosphorescent blocks, and fluorene‐based silane moieties. The photophysical and electrochemical investigations indicate not only highly efficient energy‐transfer from the organic segments to the phosphorescent units in the polymer backbone but also the ambipolar character of the copolymers. Benefiting from all these merits, the phosphorescent polymers can furnish organic light‐emitting diodes (OLEDs) with exceptional high electroluminescent (EL) efficiencies with a current efficiency (η _L) of 8.31 cd A⁻¹, external quantum efficiency (η _ext) of 16.07%, and power efficiency (η _P) of 2.95 lm W⁻¹, representing the state‐of‐the‐art electroluminescent performances ever achieved by red phosphorescent polymers. This work here might represent a new pathway to design and synthesize highly efficient phosphorescent polymers.

     

不同绿藻浓度下铜绿微囊藻对轮虫生活史的影响

利用生命表实验,研究了不同斜生栅藻浓度下,铜绿微囊藻对萼花臂尾轮虫和红臂尾轮虫生活史的影响.结果表明:当斜生栅藻浓度较高(105,106cells/m L)时,铜绿微囊藻对萼花臂尾轮虫的存活和繁殖有抑制作用,对照组轮虫的rm、R0均显著高于铜绿微囊藻组中的值(p0.01);当斜生栅藻浓度较低(104cells/m L)时,铜绿微囊藻对萼花臂尾轮虫种群则有一定的促进作用.任一斜生栅藻浓度下,铜绿微囊藻对红臂尾轮虫种群存活和繁殖及生活史特征参数均有抑制作用,且这种抑制作用随斜生栅藻浓度的升高而减弱.说明铜绿微囊藻对轮虫的作用受其他可食性绿藻食物浓度的影响,且这种影响随轮虫种类的不同而有差异.     

Bαlog空间到QK(p,q)空间的复合算子

运用复分析和泛函分析的理论与方法,讨论了B_(log)~α空间到Q_K(p,q)空间的复合算子C_ф:C_ф(f)=foф的有界性,得到了该算子有界的充分必要条件。     

Long-Chain Alkane Dehydrogenation over Hierarchically Porous Ti-Doped Pt–Sn–K/TiO2–Al2O3 Catalysts

Kinetics and Catalysis - Hierarchically porous γ-Al2O3, TiO2–Al2O3 composite supports, and Pt–Sn–K/Al2O3 and Pt–Sn–K/TiO2–Al2O3 catalysts were prepared...     

银耳多糖在肝癌治疗中的作用及相关机制的实验研究

目的研究银耳多糖(Tremella Polysaccharide TP)对荷HAC小鼠T细胞表面分化抗原、细胞因子、体外肿瘤细胞的杀伤作用及小鼠移植性肝癌的影响.方法用环磷酰胺和银耳多糖分别作用于荷HAC肝癌小鼠,采用免疫荧光法、流式细胞仪及酶标仪观察各组免疫功能的变化及细胞因子的表达,并分离其脾细胞,将诱导的细胞毒性T细胞(CTL细胞)分别作用于体外培养的3H-TdR标记的肿瘤细胞P815,HAC和B16,4 h后用γ-闪烁记数仪进行检测,并计算杀伤程度.检测各组肿瘤质量、体积、组织学改变和主要脏器的形态学改变.结果银耳多糖实验组总T细胞、T杀伤细胞及肿瘤坏死因子(TNF)高于对照组,其中对总T细胞及TNF上调明显.在对HAC,P815,B16肿瘤细胞的杀伤作用中,银耳多糖实验组的杀伤活性明显高于对照组,分别为23.85%,20.81%,25.43%,P<0.01,其中对B16杀伤作用最强,HAC次之,P815最弱.环磷酰胺 银耳多糖实验组上述指标与银耳多糖实验组相比有所下降,但与对照组相比则明显增高(P<0.05).治疗组肝肿瘤质量、体积均低于模型组.组织学上肿瘤坏死程度重且范围广,淋巴细胞、巨噬细胞浸润明显,纤维组织增生显著.环磷酰胺组较实验组表现的更为明显.银耳多糖实验组除脾脏外,其他主要脏器无明显形态学变化.结论银耳多糖具有激活和提高特异性和非特异性杀伤细胞的抗肿瘤作用,是一种能调节机体免疫功能、抑制肿瘤细胞增殖、分化的抗癌中药制剂.     

Syntheses and Crystal Structures of Two New Pentaborates Templated by Transition-Metal Complexes

Two new pentaborates [M(dap)₃][B₅O₆(OH)₄]₂·H₂O (M = Co (1) and Ni (2); dap = 1,2-diaminopropane) have been hydrothermally synthesized. Both structures were determined by single crystal X-ray diffraction and further characterized by elemental analysis, FT-IR, thermogravimetric analysis and photoluminescence spectroscopy. Two compounds are isostructural and consist of isolated pentaborate [B₅O₆(OH)₄]^? anions and [M(dap)₃]²⁺ complex cations. The anionic [B₅O₆(OH)₄]^? groups are linked by extensive hydrogen bonds to form a 3-D supramolecular framework with large channels, in which the transition-metal complex templates are located. The luminescent properties of 1 and 2 were studied, and blue luminescence occurs with an emission maximum at 405 and 408 nm upon excitation at 332 and 328 nm respectively. Crystal data: 1, monoclinic, space group P2₁/c (No. 14), a = 9.7159(5) Å, b = 29.3372(19) Å, c = 11.5121(6) Å, β = 103.286(5)°, V = 3193.6(3) ų, Z = 4; 2, monoclinic, space group P2₁/c, a = 9.7264(4) Å, b = 29.3810(16) Å, c = 11.5185(6) Å, β = 103.249(4)°, V = 3204.0(3) ų, Z = 4.     

Electrospinning synthesis and photocatalytic property of CaFe2O4/MgFe2O4 heterostructure for degradation of tetracycline

CaFe₂O₄/MgFe₂O₄ nanowires with heterostructure had been successfully synthesized by electrospinning method. The obtained samples were systematically characterized by scanning electron microscopy (SEM), X‐Ray diffraction (XRD), UV–Vis diffuse reflectance spectra (UV‐Vis DR) and Environment scanning electron microscopy (ESEM). The novel CaFe₂O₄/MgFe₂O₄ nanowires exhibit an enhanced photocatalytic activity for degrading of tetracycline (TC) under visible light. Compared with bare CaFe₂O₄ or MgFe₂O₄ samples, the prepared CaFe₂O₄/MgFe₂O₄ (Ca:Mg:Fe = 3:2:10) composited nanowires show the best photocatalytic performance with a degradation efficiency of 40% after 150 min reaction time. This enhancement is attributed to the heterostructure of CaFe₂O₄/MgFe₂O₄ nanowires, which effectively repress the recombination of photo‐generated electrons and holes. Based on heterostructure and energy band positions, the enhancement of mechanism under visible‐light enhances the photocatalytic activity.     

Electrochemical Phase Evolution of Metal-Based Pre-Catalysts for High-Rate Polysulfide Conversion

In situ evolution of electrocatalysts is of paramount importance in defining catalytic reactions. Catalysts for aprotic electrochemistry such as lithium–sulfur (Li-S) batteries are the cornerstone to enhance intrinsically sluggish reaction kinetics but the true active phases are often controversial. Herein, we reveal the electrochemical phase evolution of metal-based pre-catalysts (Co₄N) in working Li-S batteries that renders highly active electrocatalysts (CoS_x). Electrochemical cycling induces the transformation from single-crystalline Co₄N to polycrystalline CoS_x that are rich in active sites. This transformation propels all-phase polysulfide-involving reactions. Consequently, Co₄N enables stable operation of high-rate (10 C, 16.7 mA cm⁻²) and electrolyte-starved (4.7 μL mg_S⁻¹) Li-S batteries. The general concept of electrochemically induced sulfurization is verified by thermodynamic energetics for most of low-valence metal compounds.     

The miracle role of lattice imperfections in benzene alkylation with methanol over mordenite

Mordenite (MOR) has demonstrated potential as a catalyst for alkylation due to high variability, intrinsic porosity, and outstanding stability. However, the contact probability of benzene and methanol has been limited by typical layered structures of MOR and there is no connection between layers. Here, we report the preparedness of H-MOR via a sequential post-treatment method based on a commercial MOR. H-MOR sample had appeared lattice imperfections inferred from characterization means. The samples were tested with benezene methylation reaction. Results show that the high conversion of benzene and the high selectivity of toluene were obtained from the miracle role of lattice imperfections in the H-MOR sample. Sequentially, based on the study of all catalyst structure and physical properties, a plausible reaction mechanism for the selectivity of the desired toluene was proposed.     

Effect of ammonia,ammonia-water,and sulfuric acid on the HO2 + HO2 → H2O2 + 3O2 reaction in troposphere: Competition between stepwise and one-step mechanisms

A detailed theoretical study on the reaction mechanisms for the formations of H₂O₂ + ³O₂ from the self-reaction of HO₂ radicals under the effect of NH₃, H₃N···H₂O, and H₂SO₄ catalysts was performed using the CCSD(T)/CBS//M06-2X/aug-cc-pVTZ method. The rate constant was computed using canonical variational transition state theory (CVT) with small curvature tunneling (SCT). Our results indicate that NH₃-, H₃N···H₂O-, and H₂SO₄-catalyzed reactions could proceed through both one-step and stepwise routes. Calculated rate constants show that the catalyzed routes in the presence of the three catalysts all prefer stepwise pathways. Compared to the catalytic efficiency of H₂O, the efficiencies of NH₃, H₃N···H₂O, and H₂SO₄ are much lower due to their smaller relative concentrations. The present results have provided a definitive example of how basic and acidic catalysts influence the atmospheric reaction of HO₂ + HO₂ → H₂O₂ + ³O₂. These results further encourage one to consider the effects of basic and acidic catalysts on the related atmospheric reactions. Thus, the present investigation should have broad implications in the gas-phase reactions of the atmosphere.