β-环糊精衍生物对α-苯丙酸包结作用的研究

用紫外光谱法研究了系列β-环糊精衍生物(羟丙基-β-环糊精、羟乙基-β-环糊精和甲基-β-环糊精)对α-苯丙酸的包结作用,考察了不同β-环糊精衍生物对不同存在状态的α-苯丙酸的包结行为。结果说明,α-苯丙酸与β-环糊精衍生物形成的包合物的包合比为1∶1,三种主体环糊精的包结能力强弱顺序为:羟乙基-β-环糊精羟丙基-β-环糊精甲基-β-环糊精。羟丙基-β-环糊精适合包结分子状态的α-苯丙酸,而不易包结离子状态的α-苯丙酸。     

高光谱影像的鲜桃可溶性固形物含量预测模型

可溶性固形物含量(SSC)是决定鲜桃风味和品质的重要成分。高光谱影像的特征提取为无损检测可溶性固形物含量提供了数据基础和方法路径。先前的研究表明,基于多光谱、荧光谱、近红外光谱、电子鼻的水果内部品质评估取得较好的结果。但是,由于缺少多特征融合,从而限制了水果品质的精准估测。为此,提出了一种基于堆栈自动编码器-粒子群优化支持向量回归(SAE-PSO-SVR)模型预测鲜桃可溶性固形物含量。首先,利用高光谱影像提取光谱信息、空间信息及空-谱融合信息。其次,设置普适性堆栈自动编码器(SAE)提取光谱信息、空间信息及空-谱融合信息的深层特征。最后,将深层特征作为粒子群优化支持向量回归(PSO-SVR)模型的输入数据进行鲜桃可溶性固形物含量的预测。其中,对于光谱信息作为输入的SAE模型,设计了453-300-200-100-40, 453-350-250-150-50, 453-350-250-100-60的三个隐含层结构。对于空间信息作为输入的SAE模型,设计了894-700-500-300-50, 894-650-350-200-80, 894-800-700-500-100的三个隐含层结构。对于融合信息作为输入的SAE模型,设计了1347-800-400-200-40, 1347-750-550-400-100, 1347-700-500-360-150的三个隐含层结构。实验结果表明,对于输入数据分别为光谱信息、空间信息及融合信息的SAE模型,结构为453-300-200-100-40, 894-800-700-500-100和1347-750-550-400-100的模型效果较好,而且基于融合信息的模型预测精度明显优于基于光谱信息或者图像信息的模型。为了验证模型的普适性,利用结构为1347-750-550-400-100的SAE模型提取融合信息的深层特征估测不同品种鲜桃的可溶性固形物含量并进行可视化。结果表明,基于结构为1237-650-310-130的SAE-PSO-SVR模型预测效果最好(R2=0.873 3, RMSE=0.645 1)。因此,所提出的SAE-PSO-SVR模型提高了鲜桃可溶性固形物含量的估计精度,为鲜桃的其他成分检测提供了技术支撑。     

化学发光法测定水中1-溴-3-氯-5,5-二甲基海因

基于在碱性条件下 (p H 12 .0— 12 .5 ) 1-溴 - 3-氯 - 5 ,5 -二甲基海因与鲁米诺 -过氧化氢体系反应产生化学发光的性质 ,建立了一种测定其含量的新方法。 1-溴 - 3-氯 - 5 ,5 -二甲基海因的浓度在 4 .0× 10 -8— 1.0×10 -6mol/ L范围内与化学发光强度呈良好的线性关系。本方法的线性范围宽 ,灵敏度高 ,检出限为 2 .0×10 -8mol/ L。操作简单、方便。应用于游泳池水中 1-溴 - 3-氯 - 5 ,5 -二甲基海因的测定 ,结果令人满     

浙产山胡椒根挥发油化学成分的研究

采用水蒸汽蒸馏法提取挥发油,气相色谱-质谱联用法结合计算机检索对浙产山胡椒根挥发油的化学成分进行分析和鉴定,用气相色谱面积归一法计算各组分的相对百分含量。从山胡椒根的挥发油中,分析并鉴定出17种化合物。主要含1,2,3,3a,4,5,6,7-八氢-1,4-二甲基-7-(1-甲基乙烯基)-奥艹、4,6,6-三甲基-2-(3-甲基-1,3-丁二烯基)-3-氧杂环-辛烷、愈创木醇、1,2,3,5,6,7,8,8a-八氢-1,4-二甲基-7-(1-甲基乙烯基)-奥艹,它们占挥发油总量的84.75%。     

国家标准局等发布十一个声学国家标准

国家标准局、国务院环境保护领导小组及国家经济委员会等部门最近陆续批准发布了由全国声学标准化技术委员会归口和审查通过的十一个声学国家标准,其编号、名称及发布、实施日期如下: GB 3096-82 城市区域环境噪声标准 82-04-06发布,82-08-01实施 GB 3222-82 城市环境噪声测量方法 82-10-12发布,83-07-01实施。 GB 3223-82 水声换能器自由场校准方法 82-10-12发布,83-07-10实施。 GB 3449.1-82 机车车辆内部噪声测量——司机室噪声测量 82-12-31发布,83-10-01实施 GB 3450-82 机车司机室允许噪声标准 82-12-31发布,83-10-01实施 GB 3451-82 标准调音频率 82-12-31发布,83-10-01实施 GBJ 47-83 混响室法吸声系数测量规范 83-01-05发布,83-06-01实施 GB 3767-83 噪声源声功率级的测定——工程法及准工程法 83-06-03发布,84-05-01     

2,6-二氨基吡啶衍生物作为过渡金属离子荧光探针的研究

2,6-二氨基吡啶(DAPD)衍生物都有较强的荧光。除DMHND(2,4-二甲基-7-羟基-1,8-萘啶)外,2,4-二甲基-7-胺基-1,8-萘啶(DMAND)和2,4-二甲基-7-丙烯酰胺基-1,8-萘啶(DMAAN)在加入过渡金属离子后,荧光强度增强,发射光谱红移,可以作为过渡金属离子的荧光探针。根据Irving-Williams顺序,以过渡金属中络合能力较强的Cu2+为代表,求算了DMAND和DMAAN与Cu2+的结合比,通过非线性拟合计算了结合常数,比较了它们与金属离子结合的强弱,DMAND较DMAAN为更灵敏的过渡金属离子荧光探针。     

表面增强拉曼散射探测细胞酶的活性

本文以5-溴-4-氯-3-吲哚基-β-D-吡喃半乳糖苷为底物,探测细胞结构中β-半乳糖苷酶的活性。作为β-半乳糖苷酶的底物,5-溴-4-氯-3-吲哚基-β-D-吡喃半乳糖苷在细胞β-半乳糖苷酶酶解作用下,形成靛蓝染料衍生物,在贵金属表面具有较强的表面增强拉曼散射。这种通过表面增强拉曼光谱探测细胞酶活性的方法,与高速拉曼线扫描相结合,可以快速地评估细胞种群的酶活性。     

柚子皮挥发油化学成分分析

使用水蒸气蒸馏法提取柚子皮中的挥发油,利用气相色谱-质谱联用技术对柚子皮化学成分进行分离鉴定,采用色谱峰面积归一化法确定各成分的相对含量。分析结果表明,共检测出62种组分,鉴定了其中的31种组分,占挥发油组分总量的50.0%。主要成分是β-蒎烯、4,4A,5,6,7,8-六氢-4,4A-二甲基-6-(1-甲基亚乙基)-(4R-顺)-2(3H)-萘酮、氧化芳樟醇、(E,E)-3,7,11,15-四甲基-1,6,10,14-十六碳四烯-3-醇。     

利用光谱法和分子对接技术研究4-乙基-2-甲氧基苯酚与人血清白蛋白之间的相互作用

4-乙基-2-甲氧基苯酚是一种被广泛应用的食品添加剂,但它也具有一定的毒性,为了探究4-乙基-2-甲氧基苯酚对人体的影响,将多种光谱技术与分子模拟等技术结合起来对4-乙基-2-甲氧基苯酚与人血清白蛋白Human Serum Albumin(HSA)之间的相互作用进行了较全面的研究。紫外吸收光谱的结果说明,4-乙基-2-甲氧基苯酚与人血清白蛋白之间形成了新的复合物。荧光光谱的结果说明了4-乙基-2-甲氧基苯酚的存在,可以增加人血清白蛋白的荧光强度。通过15 nm的同步荧光光谱同时结合荧光增强效应方程可以计算出4-乙基-2-甲氧基苯酚与人血清白蛋白之间的结合常数,且它们之间的结合常数随着温度的升高而减小。热力学参数表明,4-乙基-2-甲氧基苯酚主要靠氢键和疏水作用力与人血清白蛋白结合在一起。同步荧光光谱、三维荧光光谱和圆二色光谱的结果说明人血清白蛋白的构象会随着4-乙基-2-甲氧基苯酚的作用而发生一定的变化。分子对接得到结果说明4-乙基-2-甲氧基苯酚键合在人血清白蛋白的IB区域。     

山绿茶化学成分的研究

硅胶柱色谱、凝胶柱色谱分离,高效液相色谱纯化,得到单体化合物,用各种有机波谱鉴定化合物结构。分离得到6个化合物,鉴定为:α-香树脂素(Ⅰ),乌索酸(Ⅱ),3β,19α-二羟基乌索-12-烯-24,28-二酸(Ⅳ),2α,3β,23-三羟基乌索-12-烯-28-羧酸(),3β,19α,20β-三羟基乌索-12-烯-24,28-二羧酸(V),3β,19α-二羟基乌索-12-烯-23,28-二羧酸(Ⅲ)。化合物Ⅰ,Ⅲ,Ⅳ,Ⅴ,Ⅵ都是首次从该植物中分离得到。     

BEPCⅡ国产500 MHz超导腔运行综述

北京正负电子对撞机二期(BEPCⅡ),国产500 MHz超导腔经过紧张的安装调试于2017年10月正式投入带束流运行。首先对此国产超导腔两次降温调试的相关参数进行了监测和对比分析;其次研究了通过高功率老练的方法改善超导腔的品质因数,并实时监测超导腔老练过程中的辐射剂量;最后对超导腔的带束流运行情况进行了介绍分析。结果表明:BEPCⅡ国产500 MHz超导腔虽然放置了6年,但是状态良好,通过高功率老练能够降低超导腔的辐射剂量,改善其性能,完全满足束流运行要求。     

Viscosity and electric properties of water aerosols

The flow of water mist in a narrow duct has been studied experimentally. The profile of the velocity of drops has been measured, and the viscosity of the mist has been calculated using the Navier–Stokes equation. It has been found that at low gradients of the rate of shear the viscosity of the mist can exceed that of clean air by tens and even hundreds of times. The electric charge of the drops has been measured. It has been found that the viscosity of the mist differs from that of clean air at gradients of the rate of shear that are less than the frequency of the establishment of electric equilibrium between the drops. A comparative analysis of the viscosities of the mist and a drop cluster has been carried out, and the dependence of the viscosity of the water aerosol on the radius and the charge of the drops has been predicted. The possible role of aerosols that contain submicron drops in the known “clear air turbulence” problem has been shown.     

稀土和锕系化合物中重费密子行为

本文采用周期Anderson哈密顿量研究了稀土和锕系化合物中的重费密子行为。对f电子间库仑关联项做了平均场近似并引入自能项反映多体作用的效应。对自能项采用了单格位近似,在准粒子表象中讨论了系统的性质,通过对f电子平均占据数的自洽计算,得到了准粒子有效质量,讨论了形成重费密子的条件,以及相应的磁性的变化,并做了数值计算。所得结果与最近的实验进行了比较。 关键词：     

Magnetic structure of the compensated ferromagnet-multiferroic interface

The magnetic structure of the compensated ferromagnet-multiferroic interface has been considered. The law governing the decrease of distortions of magnetic order parameters with increasing distance from the interface has been found. An expression for the energy of interlayer interaction of magnetic order parameters has been derived, and it has been shown that its magnitude is determined by the exchange interaction. The condition for magnetization switching of the ferromagnetic layer by an electric field applied to the multiferroic layer has been formulated. It has been demonstrated that the magnetoelectric effect and weak ferromagnetism are not prerequisites to the development of electric field-switchable magnetoresistive memory.     

Specific features of the structure of detonation nanodiamonds from results of electron microscopy investigations

The experimental results of a comprehensive investigation of the structure of detonation synthesis nanodiamonds by electron microscopy methods have been presented. The morphology of diamond nanoparticles has been investigated and the microdiffraction patterns have been analyzed. The method of characteristic fast electron energy loss spectroscopy in transmission electron microscopy has been used. The local density of structural components of a nanodiamond (diamond core and fullerene-like shell) has been obtained. The shape of the shell surrounding the nanocrystal has been determined using model calculations. A hypothesis explaining the charging of the nanodiamond surface has been proposed.     

Generalized classical mechanics

Generalized classical mechanics has been introduced and developed as a classical counterpart of the fractional quantum mechanics. The Lagrangian of generalized classical mechanics has been introduced, and equation of motion has been obtained. Lagrange, Hamilton and Hamilton-Jacobi frameworks have been implemented. Oscillator model has been launched and solved in 1D case. A new equation for the period of oscillations of generalized classical oscillator has been found. The interplay between the energy dependency of the period of classical oscillations and the non-equidistant distribution of the energy levels for fractional quantum oscillator has been discussed. We discuss as well, the relationships between new equations of generalized classical mechanics and the well-known fundamental equations of classical mechanics.     

Bistability of a “chevron” smectic C* liquid crystal in an external electric field

The system of nonlinear equations describing a surface-stabilized ferroelectric smectic C* liquid crystal in the chevron geometry has been investigated by numerical methods in the framework of the continuum model of liquid crystals. Stable orientational and structural configurations have been studied, and the results obtained have been compared with those derived using simplified models. The height of the potential barrier separating two stable configurations has been determined, and the transition between them under the action of the external electric field has been examined. It has been demonstrated that this effect has a threshold character. The dependence of the threshold field on the film thickness has been analyzed.     

Extremely short optical pulses in strained graphene in terms of the gauge theory

Evolution of optical pulses, which propagate in strained graphene, has been investigated. The effective wave equation for the vector potential of the electromagnetic field has been derived. The tensile strain of graphene layers has been described using the effective vector-potential in terms of the gauge theory. The numerical solution of the derived wave equation has been presented and the dependence of the pulse strength and shape on the magnitude of the external strain has been analyzed.     

Zitterbewegung in thin-film topological insulators in the presence of a terahertz pulse

Zitterbewegung (trembling motion) in thin-film topological insulators in the presence of a terahertz pump pulse has been considered. An analytical expression for the electric current density has been derived, which describes the electric current induced by the motion of an electron wave packet. The electron subsystem has been considered in the long-wavelength approximation, and the electromagnetic field has been described classically in the constant-pump approximation. The numerical analysis of the results has been carried out.     

Current-induced spin polarization of holes in tellurium

The current-induced optical activity in a tellurium single crystal has been experimentally investigated in the mid-infrared spectral region. The phenomenological theory of the current-induced optical activity has been considered and the microscopic mechanism of this phenomenon has been described. The dependence of the degree of spin polarization of holes in tellurium on the electric current density has been determined. An approximate analytical expression relating the current-induced optical activity to the degree of spin polarization of holes has been obtained.