The synthesis of mesoporous zeolite beta aggregates without the use of second template and additive

Zeolite Beta Aggregates have been synthesized by the self-assembly of Beta nanoparticles without the use of second template or additive, where the large zeolitic aggregates avoided the filtration difficulties and the presence of mesopore reduced the diffusion limitation. The samples were characterized by XRD, N₂-sorption, SEM, TEM, thermogravimetric analysis, IR spectroscopy and temperature programmed desorption of ammonia. The results showed that the SiO₂/Al₂O₃ ratio played a key role on the particle size, mesopore volume and particle–particle aggregation process of zeolite Beta. The sample with SiO₂/Al₂O₃ ratio below 60 had improved textual and acidic properties and exhibited the best catalytic activity to the alkylation of phenol with tert-butanol.     

Crystal structures, luminescent properties and thermal decomposition kinetics of some binuclear lanthanide complexes with 2,3-dichlorobenzoic acid anion and 2,2′-bipyridine

Some binuclear lanthanide complexes with the general formula [Ln(2,3-DClBA)₃bipy]₂ (Ln = Sm(1), Eu(2), Tb(3), Dy(4), and Ho(5); 2,3-DClBA = 2,3-dichlorobenzoate; bipy = 2,2′-bipyridine) were synthesized and characterized by elemental analysis, molar conductance, infrared, ultraviolet, luminescent spectroscopy, thermogravimetry, and different thermogravimetry (TG–DTG) techniques. The single crystals of the complexes have been obtained except the complex 2 and their structures have been determined by single-crystal X-ray diffraction. The four complexes are isostructural and the rare earth ions are all nine coordinated. The two rare earth ions in each complex are linked by two bridging bidentate and two chelating-bridging tridentate carboxylate groups. Under ultraviolet light excitation, the europium and terbium complexes exhibited characteristic red fluorescence of Eu³⁺ ion and green fluorescence of Tb³⁺ ion at room temperature. The non-isothermal kinetics was investigated by using the integral isoconversional non-linear (NL-INT) and the Popescu methods. The mechanism functions of the first decomposition step of the complexes 3–5 were determined. Meanwhile, the thermodynamic parameters (ΔG ^≠ , ΔH ^≠, and ΔS ^≠) at DTG peak temperatures were also calculated.     

RP-HPLC同时测定白花檵木花中的槲皮素和山奈酚

建立用反相高效液相色谱法同时测定白花檵木花中槲皮素和山奈酚含量的方法。采用Eclipse XDB-C18色谱柱(4.6mm×250mm,5μm);柱温:25℃;流动相为乙腈-0.4%磷酸水溶液(35:65,V/V);流速为1.0mL·min-1;检测波长为360nm。槲皮素在1.08×10-3—1.08×10-1μg·μL-1的范围内具有良好的线性关系(r=0.9999),平均回收率97.23%,RSD为1.26%;山奈酚在1.04×10-3—1.04×10-1μg.μL-1的范围内具有良好的线性关系(r=0.9999),平均回收率99.78%,RSD为0.46%。方法简便、准确、可靠,可作为白花檵木花中槲皮素和山奈酚的定量分析方法。     

喷淋高度对氨喷雾相变冷却特性的影响

喷雾相变冷却具有高热流密度的换热能力,本文通过建立喷雾相变冷却实验系统,以液氨为工质,使用单喷嘴,对冷却面为2.5 cm×1.2 cm的热沉进行了实验研究。结果表明:以氨为工质的喷雾相变冷却具有较高的换热能力;在热流密度达到400W/cm~2时,热沉表面的温度在15℃以下;在实验工况不变时,随喷嘴喷淋高度的降低,临界热流密度值(CHF)增大,最大换热系数可达95000 W/(m~2·K)。     

大孔吸附树脂吸附法结合氯仿溶解法分离混合二元酸

建立利用大孔吸附树脂吸附法结合氯仿溶解法分离混合二元酸中丁二酸、戊二酸和己二酸的方法并使其分别达到一定的纯度和收率。首先利用LC-ESI-MS方法测定了混合二元酸中丁二酸、戊二酸和己二酸含量,然后通过对3种大孔吸附树脂AB-8、NKA-Ⅱ和D-380吸附性能的综合比较,筛选出AB-8大孔吸附树脂作为吸附剂,以水、10%、30%和95%乙醇水溶液作为洗脱剂对混合二元酸进行初步的分离,得到A、B、C和D4个分离部位,再利用氯仿对二元酸溶解度的不同,将该4个分离部位在55℃水浴恒温分别用氯仿进行溶解、过滤,通过LC-ESI-MS方法测定确定相应部位的组成情况后进行适当合并,最终达到将混合二元酸分离的目的。丁二酸纯度:70.3%,收率:92.7%;戊二酸纯度:94.1%,收率89.2%;己二酸纯度:90.7%,收率:88.7%。     

Dynamics of the Random Ising Model with Long-Range Interaction

Critical dynamics of the random Ising model with long-range interaction decaying as r-(d σ) where d is the dimensionality) is studied by the theoretic renormalization-group approach. The system is released to an evolution within a model A dynamics. Asymptotic scaling laws are studied in a frame of the expansion in = 2σ - d. In dimensions d ＜ 2σ. the dynamic exponent z is calculated to the second order in at the random fixed point.``     

溶剂对钙钛矿薄膜形貌和结晶性的影响研究

溶剂对钙钛矿太阳能电池器件有着至关重要的影响. 基于目前常用的N, N-二甲基甲酰胺(DMF)和丁内酯(GBL)溶剂, 一步溶液旋涂技术和介孔电池结构, 制备的钙钛矿薄膜的形貌、结晶性, 以及最终的器件光电转化效率存在较大的差异, 利用DMF作为溶剂, 效率仅为2.8%, 而基于GBL的电池效率可以达到10.1%. 结合SEM, HRTEM, XRD和UV等表征手段, 分析了钙钛矿从DMF溶液和GBL溶液中结晶析出的不同机理, 明确了溶剂跟PbI₂的配位作用对钙钛矿的溶解、析出过程的制约作用, 揭示了造成器件效率差异的本质原因.     

甲氨蝶呤/层状双金属氢氧化物的性能调控及细胞生物实验研究

在乙醇-水混合体系中,以氨水为沉淀剂共沉淀合成了甲氨蝶呤/层状双金属氢氧化物（MTX/LDH）纳米复合物,采用控制水热处理时间的方式来调控其性能。利用X-射线衍射（XRD）、透射电镜（TEM）和红外光谱（FT-IR）等表征手段,对其结构及形貌进行了表征。研究表明：MTX分子以单层倾斜或垂直方式插入LDH层间,随着水热处理时间的不同,MTX在层间的倾斜角度发生了变化;水热处理时间对产物的结晶度、粒径和层间排列方式都有影响,当水热处理时间为12h时,得到的MTX/LDH纳米复合物的结晶度最高,单分散性最好。在磷酸缓冲液中考察了MTX/LDH纳米复合物的缓释性能,结果表明样品均呈现出良好的缓释性能,释放速率先快后慢。重点考察了这几种MTX/LDH纳米复合物作用于肺癌细胞A549的细胞生物实验,研究表明这几种复合物对肺癌细胞A549都具有良好的抑制作用,其效果与纳米复合物的单分散性和粒径有密切的关系,单分散性越好,粒径分布越均匀,对A₅₄₉癌细胞的抑制效果越好。     

Analysis of triacylglycerol hydroperoxides in human lipoproteins by Orbitrap mass spectrometer

Herein, we represent a simple method for the detection and characterization of molecular species of triacylglycerol monohydroperoxides (TGOOH) in biological samples by use of reversed-phase liquid chromatography with a LTQ Orbitrap XL mass spectrometer (LC/LTQ Orbitrap) via an electrospray ionization source. Data were acquired using high-resolution, high-mass accuracy in Fourier-transform mode. Platform performance, related to the identification of TGOOH in human lipoproteins and plasma, was estimated using extracted ion chromatograms with mass tolerance windows of 5 ppm. Native low-density lipoproteins (nLDL) and native high-density lipoproteins (nHDL) from a healthy donor were oxidized by CuSO₄ to generate oxidized LDL (oxLDL) and oxidized HDL (oxHDL). No TGOOH molecular species were detected in the nLDL and nHDL, whereas 11 species of TGOOH molecules were detected in the oxLDL and oxHDL. In positive-ion mode, TGOOH was found as [M + NH₄]⁺. In negative-ion mode, TGOOH was observed as [M + CH₃COO]^–. TGOOH was more easily ionized in positive-ion mode than in negative-ion mode. The LC/LTQ Orbitrap method was applied to human plasma and three molecular species of TGOOH were detected. The limit of detection is 0.1 pmol (S/N?=?10:1) for each synthesized TGOOH.