受限于碳纳米管中水分子特性的分子动力学模拟研究

利用分子动力学模拟研究了常温常压下受限于（8,8）（9,9）和（10,10）单壁碳纳米管中的水分子,对受限水分子平衡体系的状态和径向分布函数等静态性质进行了分析。结果显示,在不同管径的碳纳米管内部,水分子的微观结构都有高度的有序性。通过做水分子在碳纳米管内的均方位移与时间关系图,利用Einstein法算出不同管径中水分子的扩散系数,然后利用Knudsen扩散公式计算出的水分子的扩散系数,对种方法的计算结果进行比较。     

二甲醚储罐的安全风险及运行管理

对二甲醚罐区进行了重大危险源的辨识;通过数学模型,模拟分析了二甲醚储罐和罐区池发生火灾或爆炸事故时的危害程度;从储罐设计、维护和管理方面,提出了二甲醚储罐的安全运行措施.     

钛铁矿和高磷铁矿混合矿氧气顶吹熔融还原炼铁的工艺条件

采用氧气顶吹熔融还原法进行了高磷铁矿和钛铁矿混合矿炼铁的实验研究,考察了熔渣四元碱度、反应温度、碳氧摩尔比、通氧时间、保温时间和氧流量对炼铁效果的影响. 结果表明,提高反应温度、在一定范围内增加CaO加入量、提高碳氧摩尔比、延长通氧时间和保温时间、增加氧流量都能不同程度地提高铁还原率. 确定的合理工艺条件为：温度1500℃,碱度1.3,碳氧摩尔比1.0,保温时间30 min,通氧时间10 min,氧流量350 L/h,在此条件下渣铁分离较好,铁还原率达96.17%.     

Enhanced wettability and thermal stability of polypropylene separators by organic–inorganic coating layer for lithium‐ion batteries

Organic–inorganic coating polypropylene separators were developed by introducing SiO₂ nanoparticles through sol–gel process, where polydopamine was used as an intermediate layer. Scanning electron microscopy results showed the coating layers have highly porous structure, which was beneficial for liquid electrolyte uptake. Compared with pristine polypropylene separator, the ceramic separators showed improved thermal stability, higher ionic conductivity, and lower interfacial impedance. The cells employing the ceramic separators delivers excellent discharge capacity (retention = 75%) and coulombic efficiency up to 98% at 2 °C rate after 100 cycles. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46478.     

Three‐dimensional color prediction modeling of single‐ and double‐layered woven fabrics

In this research, the three‐dimensional structural and colorimetric modeling of three‐dimensional woven fabrics was conducted for accurate color predictions. One‐hundred forty single‐ and double‐layered woven samples in a wide range of colors were produced. With the consideration of their three‐dimensional structural parameters, three‐dimensional color prediction models, K/S‐, R‐, and L*a*b*‐based models, were developed through the optimization of previous two‐dimensional models which have been reported to be the three most accurate models for single‐layered woven structures. The accuracy of the new three‐dimensional models was evaluated by calculating the color differences ΔL*, ΔC*, Δh°, and ΔE_CMC(2:1) between the measured and the predicted colors of the samples, and then the error values were compared to those of the two‐dimensional models. As a result, there has been an overall improvement in color predictions of all models with a decrease in ΔE_CMC(2:1) from 10.30 to 5.25 units on average after the three‐dimensional modeling.     

氧化石墨烯固定化α-淀粉酶

以石墨粉为原料,使用改进Hummer法制备氧化石墨烯,采用沉积法固定化α-淀粉酶,并对固定条件进行优化。分别采用NaOH-CH₂ClCOOH法和HNO₃-H₂SO₄法制备羧基化氧化石墨烯,并将其用于固定化α-淀粉酶。结果表明,沉积法固定化酶的最适宜温度为65 ℃,最适宜pH=7.0。连续催化反应9次后,固定化酶活力仍能保持初始固定化酶活力的47.81%。经比较发现,NaOH-CH₂ClCOOH法更有利于羧基化氧化石墨烯的制备,该方法制备的羧基化氧化石墨烯产率为HNO₃-H₂SO₄法的1.2倍。     

Preparation and properties of Eu and Dy co-doped strontium aluminate long afterglow nanomaterials

The long afterglow nanomaterials of strontium aluminate co-doped by Eu and Dy have been synthesized by co-precipitation combined hydrothermal method. The effects of hydrothermal time, calcination time, pH value, the amount of aluminum nitrate, activator, co-activator and flux H₃BO₃ on the fluorescence properties of the product were investigated by means of single factor optimization experiment. Then the orthogonal experiment was employed to obtain the optimal synthesis conditions that are as follows: n_Dy/n_Eu = 2.5, t_c = 2.5?h, n_Eu/n_Sr = 0.02, t_h = 8?h. Subsequently, the optimal synthesis conditions were verified by three repeated experiments, and the obtained products were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and fluorescence spectrometer. The results showed that the synthesized target products all were the mixed crystal phase of SrAl₂O₄ and Sr₄Al_l4O₂₅. The particles presented regular spherical-like with size ~ 100?nm. The dopants Eu and Dy were confirmed existed in the SrAl₂O₄ powders. The fluorescence and afterglow data of the target products were better than that in the orthogonal experiment scheme. The primary emission spectra band was in the range of 400–600?nm with characteristic peak located at ~ 460?nm corresponding to the transitions of Eu²⁺ ions from 4f⁶5d→4f⁷, and the blue light can be observed by naked eyes. The similar fast-decaying and slow-decaying processes were displayed in all the afterglow curves, and the initial afterglow brightness of the target product is apparently higher than that of products synthesized by the orthogonal experiment. The synthesized target products, which show excellent long afterglow performance, present a great application prospects in the aspects of ceramics, plastics, arts and crafts, ink and coating.     

Tunable‐focus negative poly(vinyl chloride) gel microlens driven by unilateral electrodes

Tunable‐focus microlenses are urgently required for compact optical products to replace digital zoom and obtain high‐quality images. An electrically controllable tunable‐focus negative microlens is proposed, which is based on an electroactive poly(vinyl chloride) gel plasticized by ecofriendly dioctyl terephthalate. The anode and cathode of the microlens are simply assembled on the same side of the electrorheological elastomer, which greatly saves space and allows the thickness of the proposed microlens to be less than 1 mm. By applying voltages ranging from 0 to 1000 V, the stable focus of the microlens is interestingly able to vary as wide as from –∞ to ?21.3 mm correspondingly. The proposed microlens is simple and thin but is flexible and stable and has a wide range of the focus variation, showing promising applications in minielectric and optical devices. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46136.     

Assessment of conversion efficiency of Cr4+ ions by aliovalent cation additives in Cr:YAG ceramic for edge cladding

0.25at.% Cr:YAG ceramics were successfully fabricated as the edge cladding of Yb:YAG transparent ceramic slabs through vacuum sintering of co‐precipitated powders, using oxide additives to introduce different cations. The effects of various cation additives (Si⁴⁺, Ca²⁺, and Si⁴⁺ + Ca²⁺) on the conversion efficiency of Cr⁴⁺ ions and optical characteristics of the Cr:YAG edge cladding were investigated. Measurements of the absorption spectra of the Cr:YAG ceramics without any additives revealed 2 absorption bands centered at 430 nm and 600 nm, which imparted the sample with a green color. The introduction of only Si⁴⁺‐bearing additive did not promote the transition of Cr ions from the 3+ to 4+ state. Theoretical analysis and experimentation revealed that the addition of CaO not only enhanced the microstructure and improved the transmittance of the Cr:YAG ceramic, but also introduced vacancies that assisted in the formation of Cr⁴⁺ ions. It was determined that CaO has the same effect on the conversion efficiency of Cr⁴⁺ ions whether it is added as a single additive or in combination with SiO₂. The underlying mechanisms by which these aliovalent cation additives influence the formation of Cr⁴⁺ ions and affect optical properties are discussed in detail. High quality composite ceramics with Yb:YAG transparent ceramic slabs and dark brown‐colored Cr⁴⁺: YAG ceramic edge cladding were achieved through the addition of 0.05 wt.% CaO to the edge cladding, with no interfacial effects between the 2 regions being observed.     

化妆品功效评价(Ⅲ)——美白功效宣称的科学支持

概述了皮肤颜色的影响因素、黑色素形成及美白机理,介绍了生物化学法、物理化学法、细胞生物学法、三维重组皮肤模型替代法、动物实验法、主观评价法、客观仪器评价法等美白化妆品功效评价方法,提供了美白功效评价的新思路,展望了美白化妆品功效评价方法的未来发展趋势。