毛细管电泳法测定β-环糊精与芦荟大黄素包合反应平衡常数

在25 ℃条件下,利用毛细管电泳法测得β-环糊精与芦荟大黄素在pH=9.7、浓度为0.015 mol/L的硼砂缓冲溶液中的包合反应平衡常数为27.5 L/mol. 由于芦荟大黄素具有强疏水性,故其与环糊精的结合力应属于疏水作用力.     

氢化与氟化五边形石墨烯双层电子性能调控的第一性原理研究

基于密度泛函理论的第一性原理计算方法,我们研究了氢化、氟化及氢氟化五边形石墨烯双层对其电子性能的调控.计算结果表明,氢化和氟化的五边形石墨烯双层可分别在价带顶及导带底形成局域的电子态而显著降低带隙.基于这一特性,我们进一步研究氢氟化的五边形石墨烯双层结构对电子能带的影响,并且发现通过调控氢氟化覆盖度能够有效调节带隙,进而实现五边形石墨烯双层从半导体到金属态的转变.     

Semi-theoretical analyses of the concrete plate perforated by a rigid projectile

Based on the three-stage perforation model, a semi-theoretical analysis is conducted for the ballistic performances of a rigid kinetic projectile impacting on concrete plates. By introducing the projectile resistance coefficients, dimensionless formulae are proposed for depth of penetration (DOP), perforation limit thickness, ballistic limit velocity, residual velocity and perforation ratio, with the projectile nosed geometries and projectile-target interfacial friction taken into account. Based on the proposed formula for DOP and lots of penetration tests data of normal and high strength concrete targets, a new expression is obtained for target strength parameter. By comparisons between the results of the proposed formulae and existing empirical formulae and large amount of projectile penetration or perforation tests data for monolithic and segmented concrete targets, the validations of the proposed formulae are verified. It is found that the projectile-target interfacial friction can be neglected in the predictions of characteristic ballistic parameters. The dimensionless DOP for low-to-mid speed impacts of non-flat nosed projectiles increases almost linearly with the impact factor by a coefficient of 2/(πS). The anti-perforation ability of the multilayered concrete plates is dependent on both the target plate thickness and the projectile impact velocity. The variation range of the perforation ratio is 1–3.5 for concrete targets.     

高压微波辅助提取法提取牛黄上清丸中的黄芩苷

采用高压微波辅助提取法提取牛黄上清丸中的黄芩苷, 利用蜜丸的粘性, 将蜜丸涂敷在自制毛玻璃片表面后, 置于高压微波提取装置中进行提取, 同时与直接将蜜丸切块置于微波装置进行了对比.     

Non-polar Solvent Microwave-Assisted Extraction of Volatile Constituents from Dried Zingiber Officinale Rosc.

A new method, non-polar solvent microwave-assisted extraction （NPSMAE）, was applied to the extraction of essential oil from Zingiber officinale Rosc. in closed-vessel system. By adding microwave absorption mediumcarbonyl iron powders （CIP） into extraction system, the essential oil was extracted by the non-polar solvent （ether） which can be heated by CIP. The constituents of essential oil obtained by NPSMAE were comparable with those obtained by hydrodistillation （HD） by GC-MS analysis, which indicates that NPSMAE is a feasible way to extract essential oil from dried plant materials. The NPSMAE took much less extraction time （5 min） than HD （180 min）, and its extraction efficiency was much higher than that of conventional polar solvent microwave-assisted extraction （PSMAE） and mixed solvent microwave-assisted extraction （MSMAE）. It can be a good alternative for the extraction of volatile constituents from dried plant samples.     

A new strategy for the detection of adenosine triphosphate by aptamer/quantum dot biosensor based on chemiluminescence resonance energy transfer

We designed an aptasensor for the detection of adenosine triphosphate (ATP) based on chemiluminescence resonance energy transfer (CRET). An adenosine aptamer was cut into two pieces of ssDNA, which were attached to quantum dots (QDs) and horse radish peroxidase (HRP), respectively. They could reassemble into specific structures in the presence of ATP and then decrease the distance of HRP and QDs. ATP detection can be easily realized according to the fluorescent intensity of QDs, which is excited by CRET between luminol and QDs. Results show that the concentration of ATP is linear relation with the fluorescent intensity of the peak of QDs emission and the linear range for the linear equation is from 50 μM to 231 μM and the detection limit was 185 nM. When the concentration of ATP was 2 mM, the efficiency of CRET is 13.6%. Good specificity for ATP had been demonstrated compared to thymidine triphosphate (TTP), cytidine triphosphate (CTP) and guanosine triphosphate (GTP), when 1 mM of each was added, respectively. This method needs no external light source and can avoid autofluorescence and photobleaching, and ATP can be detected selectively, specifically, and sensitively in a low micromolar range, which means that the strategy reported here can be applicable to the detection of several other target molecules.     

电子碰撞原子(e,2e)反应的复极化势

研究包括连续通道等非处理通道的复极化势对(e,2e)碰撞过程三重微分截面的影响,即将耦合通道光学势方法得到的复极化势附加到畸变波玻恩近似方法的畸变势中,在靶态的HF近似下,计算了Ar原子和Ne原子在非共面对称几何条件下(e,2e)反应的三重微分截面.对于较高的入射能量,在实验的误差范围内,计算结果与电子动量谱的实验数据符合较好,复极化势的影响很小;对于较低的入射能量,复极化势的作用明显增大. 关键词： 复极化势 (e;2e)反应 三重微分截面 电子动量谱     

Heat capacities and thermodynamic properties of M(HBTC)(4,4′-bipy)·3DMF (M?=?Ni and Co)

Two metal?Corganic frameworks (MOFs) of M(HBTC)(4,4??-bipy)·3DMF [M?=?Ni (for 1) and Co (for 2); H₃BTC?=?1,3,5-benzenetricarboxylic acid (1,3,5-BTC); 4,4??-bipy?=?4,4??-bipyridine; DMF?=?N,N??-dimethylformamide] were synthesized by a one-pot solution reaction and a solvothermal method, respectively, and characterized by powder X-ray diffraction and FT-IR spectra. The low-temperature molar heat capacities of M(HBTC)(4,4??-bipy)·3DMF were measured by temperature-modulated differential scanning calorimetry (TMDSC) for the first time. The thermodynamic parameters such as entropy and enthalpy relative to reference temperature 298.15?K were derived based on the above molar heat capacity data. Moreover, the thermal stability and the decomposition mechanism of M(HBTC)(4,4??-bipy)·3DMF were investigated by thermogravimetry analysis (TGA). The experimental results through TGA measurement demonstrate that both of the two compounds have a three-stage mass loss in air flow.     

A modified transfer matrix method for the study of the bending vibration band structure in phononic crystal Euler beams

We introduce a modified transfer matrix (MTM) method for the calculation of the bending vibration band structure of one-dimensional phononic crystal (PC) Euler beams. A particular combination of hyperbolic functions and triangular functions is introduced to transform the state parameters of the transfer matrix (TM) method into four initial parameters, which have the explicit meanings of the displacement, rotation angle, bending moment and shear force at one beam end. The method is used to calculate the band structures of two PC Euler beams constructed from aluminum–Lucite and 100 kinds of materials. The effectiveness and high efficiency of the MTM method are demonstrated by the results. Several advantages make it a proper choice for the calculation of the bending vibration band structure of PC Euler beams.