Novel Bi2O3 nanoporous film fabricated by anodic oxidation and its photoelectrochemical performance

Novel bismuth oxide (Bi₂O₃) nanoporous films were fabricated through anodization of bismuth foil in electrolytes containing glycol, ammonium sulfate ((NH₄)₂SO₄) and deionized (DI) water. Scanning electron microscopy analysis indicated that morphology of the anodized bismuth foil changed markedly along with the changing of oxidation time, water content, electrolyte concentration, temperature, and applied voltages. The optimized morphology was obtained when bismuth was anodized at 20 V, 40 °C for 40 min in glycol solution containing 0.3 wt% (NH₄)₂SO₄ and 5 wt% DI water. The composition and crystal structure of the samples formed in the optimized conditions were characterized by energy-dispersive spectroscopy and X-ray diffraction. Results showed that the as-prepared nanoporous structures were amorphous. β-Bi2O3 was obtained when the samples were annealed at 200 °C. The photocurrent response experiments demonstrated that the Bi₂O₃ nanoporous film can generate photocurrent as large as 2.893 and 6.980 μA/cm² under 0 and 0.5 V bias voltage versus saturated calomel electrode, respectively.     

FIA—ICP—AES法测定土壤提取液中游离氧化铁的研究

研究了土壤提取液中游离氧化铁含量的ＦＩＡ－ＩＣＰ－ＡＥＳ测定法。考察了采术量以及提取剂（盐酸羟胺和草酯）的浓度对的影响。试验表明：如果选择５０μＬ采样环进样，并将盐酸羟爱和草酸的浓度控制在１０ｍｇ．ｍＬ＾－１以下，则进样顺畅，不出现喷雾嘴堵塞的现象，分析线的背景干扰也得到有效抑制。此法的回收率为９７．６％～１００％，ＲＳＤ≤３．５％。     

牛顿环实验误差的探讨

对牛顿环实验中干涉宽度的变化对测量过程中各种物理量的影响进行分析,提出了牛顿环实验数据处理方法,找到了减小测量误差钧途径。     

Effects of lithium excess amount on the microstructure and electrochemical properties of LiNi<Subscript>0.5</Subscript>Mn<Subscript>1.5</Subscript>O<Subscript>4</Subscript> cathode material

Spinel LiNi_0.5Mn_1.5O₄ cathode materials with different lithium excess amount (0, 2%, 6%, 10%) were synthesized by a facile solid-state method. The effect of lithium excess amount on the microstructure, morphology, and electrochemical properties of LiNi_0.5Mn_1.5O₄ materials was systematically investigated. The results show that the lithium excess amount does not change the particle morphology and size obviously; thus, the electrochemical properties of LiNi_0.5Mn_1.5O₄ are mainly determined by structural characteristics. With the increase of lithium excess amount, the cation disordering degree (Mn³⁺ content) and phase purity first increase and then decrease, while the cation mixing extent has the opposite trend. Among them, the LiNi_0.5Mn_1.5O₄ material with 6% lithium excess amount exhibits higher disordering degree and lower impurity content and cation mixing extent, thus leading to the optimum electrochemical properties, with discharge capacities of 125.0, 126.1, 124.2, and 118.9 mAh/g at 0.2-, 1-, 5-, and 10-C rates and capacity retention rate of 96.49% after 100 cycles at 1-C rate.     

非线性半定规划一个全局收敛的无罚无滤子SSDP算法

提出了一个求解非线性半定规划的无罚函数无滤子序列二次半定规划(SSDP)算法. 算法每次迭代只需求解一个二次半定规划子问题确定搜索方向; 非单调线搜索保证目标函数或约束违反度函数的充分下降, 从而产生新的迭代点. 在适当的假设条件下, 证明了算法的全局收敛性. 最后给出了初步的数值实验结果.     

Novel Small Four-armed Molecules with Triphenylamine-bridged Structure for Organic Solar Cells Featuring High Open-circuit Voltage

In view of few attention on star-shaped molecules containing triphenylamine(TPA) unit as π-linker, a series of small four-armed molecules, consisting of octyloxy-substituted 2,1,3-benzothiadiazole(DOBT) or 4-octyl-2-thienyl functionalized DOBT as the core, TPA as π-bridge and 4-methylphenyl or 4-methoxyphenyl groups as terminal units, was designed and synthesized. The effects of π-bridges and substitute groups on molecular photoelectric performance and photovoltaic performance were fully explored. With the help of the additional thiophene-linkers incorporation, 3-octylthienyl substituted molecule with end-capping 4-methylphenyl(T-BTTPAM) and 3-octylthienyl substituted molecule with end-capping 4-methoxyphenyl(T-BTTPAOM) showed stronger and broader absorption, as well as higher charge mobilities compared to the molecules without thiophene-linkers(BTTPAM and BTTPAOM). Additionally, changing substitute groups from methyl to methoxy helped BTTPAOM and T-BTTPAOM achieve better absorption properties than BTTPAM and T-BTTPAM, respectively. When paired with PC₆₁BM as the electron acceptor to fabricate solution-processed photovoltaic devices, the four materials gave high open-circuit voltage(V_oc) values over 0.90 V. These results demonstrate that our materials are promising candidates as donor materials for organic solar cells(OSCs), and further device optimization is in progress in our laboratory.     

Influence of the polarization direction of two-beam coupling in photorefractive Bi12SiO20: Diffusion regime

Beam coupling effects in an optically active photorefractive crystal of Bi₁₂SiO₂₀ are very much influenced by the polarization direction of the interacting beams. Analytic expressions for the signal amplification in the diffusion regime have been derived for two commonly used crystallographic configurations,G<001> andG<110>,G being the grating vector. It is shown that only the <001> orientation is suitable for signal amplification. The results obtained for the diffusion regime can be applied, as a first approximation, to the more common and more intricate drift regime in which a bias electric field is applied to the crystal to enhance the coupling effect.     

Metal–Organic Framework for Emulsifying Carbon Dioxide and Water

Forming emulsions of carbon dioxide (CO₂) and water can largely expand the utility of CO₂. Herein we propose for the first time the utilization of a metal–organic framework (MOF) for emulsifying CO₂ and water. Owing to the hybrid composition, MOF particles can easily assemble at the CO₂/water interface to create a rigid protective barrier around the dispersed droplet. The MOF‐stabilized CO₂ and water emulsion has exceptional stability compared to those emulsions stabilized by surfactants or other solids. Moreover, the CO₂ and water emulsion stabilized by MOF is “tunable” due to the designable features of MOFs and adjustable character of CO₂. Such a novel kind of emulsion composed of CO₂, water, and MOF provides a facile route for constructing MOF superstructures with many advantages. The macroporous networks and hollow capsules of different kinds of MOFs have been successfully derived from CO₂ and water emulsions.     

A contribution to the volumetric electrometric determination of some organic peroxides in alkaline media

Conditions for the determination of DBP, CHP, MEKP, and MCHP, as well as m-chloroperbenzoic acid, with a standard solution of SnII-glyc or SnII-sorb by the potentiometric, bipotentiometric, and biamperometric method were found. Quite good results were obtained in comparison with individual modifications of the iodometric method. Large positive errors were found only for the determination of m-chloroperbenzoic acid with SnII-glyc. The reductometric procedure is an advantage in the determination of organic peroxides by this procedure.