简论加强化学科技伦理教育的重要意义

化学科学与人类生活密不可分,对人类的可持续发展至关重要。若科技与伦理的关系不和谐,必定会影响到整个人类社会发展的和谐性。化学作为一门重要的自然科学,化学科技伦理在当前科技伦理教育中的重要地位日益突出,在教学中加强化学科技伦理教育具有非常重要的意义。     

有限级超越整函数的(微-)差分多项式的零点分布

作者研究了有限级超越整函数的差分多项式和微-差分多项式的零点分布,在一定条件下得到了这些多项式的零点收敛指数的精确估计.所得结果可视为Hayman关于Picard例外值的经典结果的(微-)差分模拟.     

A Study of the Mechanism of Particle Size Control of Ferrous Oxalate Dihydrate by N,N-Diethylacetamide

Journal of Solution Chemistry - Density functional theory was used to study the effect of N,N-diethylacetamide (DEAc) in the preparation of ferrous oxalate dihydrate. The calculation results...     

Pre-irradiation-induced graft reaction of maleic anhydride onto polypropylene

The radiation induced graft polymerization is a well-known method to obtain new materials. Until recently, only conventional radiation sources, such as Co-60 and electron beams, were used. Moreover, part of the damage induced in polymers by heavy ions can produce active sites (peroxides and hydroperoxides) that are useful to initiate grafting reactions. Maleic anhydride (MAH) was grafted onto polypropylene (PP) wax with a number-average molecular weight (Mn) of 8000 by gamma pre-irradiation technique. Effects of total dose, monomer concentration, reaction time, and temperature on percentage of grafting are studied in detail. It is shown that the optimum conditions for grafting are temperature of 70 ^°C and total dose of 14.4 kGy. PP-g-MAH is characterized by infrared spectrum. Differential scanning calorimetry shows that the compatibility of PP-g-MAH is better than that of PP.     

A simple generation of tunable inhomogeneously polarized beam by half-wave plate

Polarization which has attracted much attention plays an important role in many optical systems, and vector beam generation is very desirable. In this paper, a very simple method for generating tunable inhomogeneously polarized beam is proposed. Polarizing film is employed to construct conic polarization converter that can convert incident beam into inhomogeneously polarized vector beam. Two half-wave plates are put in light path, and by adjusting the angle between the fast axes of the two half-wavelength plates, the polarization distribution can be altered conveniently. Experiments have been made successfully to show that this kind of method is very simple and valid.     

Hyperbolic-cosine-Gaussian beam with sine-azimuthal variation wavefront

Intensity distribution in focal plane plays an important role in many optical systems and has attracted much attention. In this paper, focusing properties of hyperbolic-cosine-Gaussian (cosh-Gaussian) beam with sine-azimuthal variation wavefront is investigated. Wavefront distribution is the sine function of the azimuthal angle. Results show that the sine parameter in the sine part of the cosh-Gaussian and decentered parameter associated with the cosh parts affect focal pattern considerably. Many novel focal patterns may occur, including cross-shape focal pattern with four intensity peak, intensity peak array, intensity peak wheel, and swallowtail multiple-peak focal pattern. The focal pattern evolution principle on increasing decentered parameter differs remarkably for different sine parameter. In addition, some focal spots are smaller than focal spot with incident Gaussian beam, which means super resolution effect appears under condition of certain sine parameter and decentered parameter.     

双沃拉斯顿棱镜光强分束比精确分析

利用折射定律,介质膜两侧折射率不同时多光束干涉理论和菲涅耳公式,精确推导了双沃拉斯顿棱镜的光强分束比的具体表达式。以公式为基础,通过Matlab软件数值模拟作图分析光强分束比随入射角、入射波长和结构角的变化关系曲线。结果表明:在棱镜为介质胶合型时,光强分束比随入射角和入射波长的变化很小,光强分束比基本为1;棱镜为空气胶合型时,光强分束比随入射角,结构角和波长的变化很大。两种情况下,光强分束比随各参量的变化基本呈周期性变化。     

Surface-enhanced Raman scattering of trans-1,2-bis (4-pyridyl)-ethylene on silver by theory calculations

Surface-enhanced Raman spectra of trans-1,2-bis (4-pyridyl)-ethylene (t-BPE) on silver foil were detected at laser line of 514.5, 633, 785 and 1064 nm, respectively. The structure of Ag-t-BPE, Ag4-t-BPE, Ag6-t-BPE, Ag10-t-BPE and Ag20-t-BPE complexes has been calculated using a local version of the Amsterdam density functional program package. The Raman spectra and electronic polarizability of t-BPE-Ag at 514.5, 633, 785 and 1064 nm excitation lines were calculated. The Raman bands of t-BPE were assigned according to the calculation of potential energy distribution. The experimental and calculated Raman spectra of t-BPE-Ag at 514.5, 633, 785 and 1064 nm were compared. The relative Raman intensities change at different excitation lines were discussed based on the Raman enhanced mechanism and surface selection rules.     

On-line microheterogeneity analysis and rapid phenotyping of haptoglobin by capillary electrophoresis using sodium dodecyl sulfate as additive

To improve the detection sensitivity and determine phenotypes of haptoglobin (Hp), a prefilling technique was developed and tested in capillary electrophoresis (CE) with UV–vis absorbance detection. Adding 0.01% sodium dodecyl sulfate (SDS) to the protein sample and 0.1% SDS to the prefilling buffer solution, on-line stacking and microheterogeneity separation of Hp were achieved. In addition, the influences of pH, buffer concentration, sample and prefilling buffer SDS concentration upon resolution were examined. Under optimized conditions, Hp-microheterogeneity was well resolved and two phenotypes of Hp (Hp 1-1 and Hp 2-2) were differentiated. This method was applied to the analysis of sera from normal individuals and β-Thalassemia patients. After the depletion of albumin (HSA) and immunoglobulin G (IgG), this method allowed to determine two phenotypes in different individuals and to detect the decrease of Hp in β-Thalassemia patients. Featuring high efficiency, speed and simplicity, the proposed method shows great potential for use in clinical diagnosis and proteome research.     

An approach of partial control design for system control and synchronization

In this paper, a general approach of partial control design for system control and synchronization is proposed. It turns control problems into simpler ones by reducing their control variables. This is realized by utilizing the dynamical relations between variables, which are described by the dynamical relation matrix and the dependence–influence matrix. By adopting partial control theory, the presented approach provides a simple and general way to stabilize systems to their partial or whole equilibriums, or to synchronize systems with their partial or whole states. Further, based on this approach, the controllers can be simplified. Two examples of synchronizing chaotic systems are given to illustrate its effectiveness.