第三方检测市场入侵条件下乳品供应链网络均衡研究

构建包含生鲜乳供应商、第三方检测机构、乳品制造商以及需求市场的乳品供应链网络均衡模型，揭示第三方检测机构入侵下，生鲜乳检测技术革新投入水平变化对乳品供应链各层级均衡决策的影响。研究结果表明：第三方检测机构承担生鲜乳检测技术投入，有利于供应链检测质量水平的提升，行业风险规避能力加强，供应链整体获利增加，是实现乳品供应链治理的有益尝试；生鲜乳供应商应在质量控制上占据主导地位，通过价格传导机制，促使乳制品制造商分担部分检测费用；政府在第三方检测环境下扮演监管角色，通过补贴与惩罚举措提升第三方检测机构的公平性及公正性，并通过策略调整来推动第三方检测的市场化运作。     

5-[2''-氟-4''-溴-苯甲亚胺]-8-羟基喹啉铝的量子化学研究

应用密度泛函PBE0方法优化5-[2′-氟-4′-溴-苯甲亚胺]-8-羟基喹啉铝(AlA3)及5-[2′-氟-4′-溴-苯甲亚胺]-8-羟基喹啉(HA)的几何构型,用TDDFT法计算其电子光谱,对电荷转移及金属原子与配体的结合能进行了讨论.计算结果表明:(1)AlA3配合物较稳定,但结合能略低于8-羟基喹啉铝(AlQ3).与AlQ3相比,AlA3的轨道作用较强,静电作用较弱,两者之和相近,但AlA3排斥能较大.(2)计算AlA3的两个电子吸收峰与实验结果相符.AlA3中的电荷由羟基喹啉基团通过Al原子在不同配体间转移呈现出最大吸收峰,属于AlQ3类衍生物的特征吸收峰.因为体系的共轭程度增大使LUMO轨道能降低,电子跃迁需要的能量减少,故吸收峰比AlQ3红移;(3)290 nm吸收峰是电荷由C N基团向羟基喹啉基团转移产生的.在喹啉环接上5-[2′-氟-4′-溴-苯甲亚胺]基团可望制备出波长更长的发光材料,且增加了一个较强的吸收峰.     

Efficient Laser-Diode End-Pumped Passively Q-Switched Mode-Locked Yb：LYSO Laser Based on SESAM

We report an efficient Q-switched laser action based on a semiconductor saturable absorber mirrors （SESAMs） as passively Q-switched laser starter and a Yb：LYSO alloyed crystal as gain material pumped directly by 974nm InGaAs laser diodes. The output pulse duration is measured to be about 7μs, while the average power and the repetition rate of the pulse chain are about 0.92 W and 6.2 kHz, respectively, under 12.5 W absorbed pumping power. The Q-switched mode-locked pulse train is also observed in this setup. The laser performance shows that Yb：LYSO is a promising laser gain medium for laser-diode pumped compact solid-state lasers.     

8-羟基喹啉共轭连接芳香杂环化合物的合成、荧光性质及生物活性的研究

设计合成了4个8-羟基喹啉共轭联接芳香杂环化合物来研究它们在有机发光材料和荧光探针的潜在应用。用IR, 1H NMR, 13C NMR, MS, UV确认了这些新化合物的结构。测定了化合物1-4的荧光性质,发光衰变时间和量子产率,并用密度泛函方法研究了4个化合物的几何结构和荧光发射波长的关系。在调控骨髓间充质干细胞增殖以及清除DPPH自由基的活性测试结果表明,这些化合物具有促进小鼠骨髓间充质干细胞的增殖的活性及良好的抗氧化性。     

7-氯-[1，2，3，4]-四氢吩嗪-[2，3]-并富勒烯[60]的合成

60富勒烯及其衍生物因其结构的特殊性,在有机超导、分子磁性、有机发光材料、分子器件、非线性光学活性、能量代谢和生物活性等[1]方面表现出独特的性能和潜在的应用前景,是非常活跃的研究领域之一.     

中学生对化学实验的态度及其对化学教学的启示

通过调查研究,了解当前中学生对化学实验的态度的基本情况,进而分析中学化学实验教学中问题的症结,从而为改进实验教学,全面提高实验教学的质量提供依据,以推动实验教学向着以学生为主体的方向发展。     

具有空穴传输性能高效蓝光咔唑芘

A novel bifunctional blue-light material, 9-(pyren-1-yl)-9H-carbazole (CzPy), has been syn-thesized and its structure is identified by electron ionization mass spectrometry, ¹H NMR, and element analysis. The absorption, photoluminescence spectra and thermal properties were studied, results showedthat CzPy was stable under ambient conditions with a blue-light emission (461 nm).Additionally, its electroluminescence properties were characterized with four different devices. Results indicated a maximum luminous efficiency reached 1.56 cd/A and maximum luminance up to 3526 cd/m² at 10 V with commission international De L'Eclairage coordinates of (0.20, 0.24) when it was used as emitter. Furthermore, CzPy also indicated hole-transporting ability.     

Deep-ultraviolet surface plasmon resonance of Al and Al_(core)/Al_2O_(3shell) nanosphere dimers for surface-enhanced spectroscopy

The localized surface plasmon resonance properties of Al and Alcore/Al2O3 shell nanosphere dimers with Al and Al core nanosphere radii of 20 nm and Al2O3 shell of 2 nm in the deep-ultraviolet region have been studied using the finite difference time domain method. The extinction spectra and the electric field distribution profiles of the two dimers for various gap distances between two individual nanospheres are compared with those of the corresponding monomers to reveal the extent of plasmon coupling. It is found that with the interparticle distance decreasing, a strong plasmon coupling between two Al or Alcore/Al2O3 shell nanospheres is observed accompanied by a significant red shift in the extinction spectra at the parallel polarization direction of the incident light related to the dimer axis, while for the case of the perpendicular polarization direction, a weak plasmon coupling arises characterized by a slight blue shift in the extinction spectra. The electric field distribution profiles show that benefiting from the dielectric Al2O3 shell, the gap distance of Alcore/Al2O3 shell nanosphere dimers can be tailored to < 1 nm scale and results in a very high electric field enhancement. The estimated surface-enhanced Raman scattering enhancement factors suggests that the Alcore/Al2O3 shell nanosphere dimers with the gap of < 1 nm gave rise to an enhancement as high as 8.1 × 107 for interparticle gap = 0.5 nm. Our studies reveal that the Alcore/Al2O3 shell nanosphere dimers may be promising substrates for surface-enhanced spectroscopy in the deep-ultraviolet region.     

Nonlinear polarization rotation-induced pulse shaping in a stretched-pulse ytterbium-doped fiber laser

We report on controllable pulse shaping in a Yb-doped stretched-pulse fiber laser followed by a high-power chirped pulse amplifier. We demonstrate that the pulses after an extra-cavity grating pair change their intensity profile from Lorentz to Gaussian and then to sech2 shapes by adjusting the intra-cavity polarization through a quarter-wave plate inside the fiber laser cavity. The laser pulses with different pulse shapes exhibit pulse-to-pulse amplitude fluctuation of -- 1.02%, while the sech2-shaped pulse train is provided with a more stable free-running repetition rate as a result of the stronger self-phase modulation in the fiber laser cavity than Lorentz- and Gaussian-shaped pulse trains.     

螺二芴富勒烯吡咯烷衍生物的合成及电化学和光限幅性能

设计合成了3种新颖的螺二芴键联富勒烯(C₆₀/C₇₀)吡咯烷衍生物, 其结构通过IR, ¹H NMR, ¹³C NMR和MALDI-TOF进行确证, 其电化学性质用循环伏安法进行研究. 结果表明, C₇₀衍生物6的还原电位较C₆₀衍生物7分别向负电势移动0.1, 0.12和0.01 V. 同时, 使用纳秒和飞秒激光分别研究了化合物6, 7和8的光限幅性能, 其光限幅阈值分别为15.3, 23.3和13.7 J/cm², 表明材料具有优异的光限幅性能.