双黄连口服液1H NMR质量稳定性分析方法研究

采用NOESYPR1D（水峰抑制）技术,测定双黄连口服液的¹H NMR谱图,用Mnova和Excel 2003软件分析处理谱图,以相似度为指标,判别分析不同厂家、不同批次的双黄连口服液中主要成分的差异. 所建立的双黄连口服液的¹H NMR质量分析方法可以有效判别不同批次双黄连口服液质量的差异. 实验方法简单、快速、稳定、重现性好,可以为中药成方制剂的质量评价提供新的思路和方法.     

The electrochemical preparation and microwave absorption properties of magnetic carbon fibers coated with Fe3O4 films

Electrodeposition was employed to fabricate magnetite (Fe₃O₄) coated carbon fibers (MCCFs). Temperature and fiber surface pretreatment had a significant influence on the composition and morphology of Fe₃O₄ films. Uniform and compact Fe₃O₄ films were fabricated at 75 °C on both nitric acid treated and untreated carbon fibers, while the films prepared at 60 °C were continuous and rough. Microwave measurements of MCCF/paraffin composites (50 wt.% of MCCFs, pretreated carbon fibers as deposition substrates) were carried out in the 2-18 GHz frequency range. MCCFs prepared at 60 °C obtained a much higher loss factor than that prepared at 75 °C. However, the calculation results of reflection loss were very abnormal that MCCFs prepared at 60 °C almost had no absorption property. While MCCFs prepared at 75 °C exhibited a good absorption property and obtained −10 dB and −20 dB refection loss in wide matching thickness ranges (1.0-6.0 mm and 1.7-6.0 mm range, respectively). A secondary attenuation peak could also be observed when the thickness of MCCF/paraffin composite exceeded 4.0 mm. The minimum reflection loss was lower.     

Double dark resonances and the dispersion properties in a four-level inverted-Y atomic system

The electromagnetically induced transparency (EIT) and its dispersion properties in a four-level inverted-Y atomic system are investigated. The absorption spectrum of a weak probe field shows two EIT windows (dark resonances) whose location, width, and depth can be controlled by manipulating the parameters of the coupling fields; the corresponding dispersion properties are also measured by using a Mach-Zehnder interferometer. The experimental measurements agree well with the theoretical calculations. This kind of system can find important applications in two-channel quantum communication and information storage.     

Surface profile inspection of a moving object by using dual-frequency Fourier transform profilometry

The 2π phase ambiguity caused by surface isolations and large height step can be solved by dual-frequency projection grating profilometry. However, in the Fourier transform profilometry (FTP) of a moving object, only one single deformed fringe pattern can be obtained. In order to introduce the dual-frequency technique into the FTP of moving object, a novel experimental system is designed to capture two fringe patterns with different frequency at the same time. A grating structure comprising two regions with different frequencies is projected upon the surface of the detected object. Two line-scan CCD cameras are used to capture the surface images encoded by the two kinds of patterns, respectively. By getting the corresponding image intensity at the same point of the object surface in the two acquired images, the dual-frequency technique is applied to extract the real phase without phase ambiguity. The surface profile of a specimen with a large height step is measured to prove the feasibility of the proposed method. The experimental results show that the proposed method can solve the 2π phase ambiguity problem successfully in the surface profile inspection of a moving object.     

Risk estimation of infectious diseases determines the effectiveness of the control strategy

Usually, whether to take vaccination or not is a voluntary decision, which is determined by many factors, from societal factors (such as religious belief and human rights) to individual preferences (including psychology and altruism). Facing the outbreaks of infectious diseases, different people often have different estimations on the risk of infectious diseases. So, some persons are willing to vaccinate, but other persons are willing to take risks. In this paper, we establish two different risk assessment systems using the technique of dynamic programming, and then compare the effects of the two different systems on the prevention of diseases on complex networks. One is that the perceived probability of being infected for each individual is the same (uniform case). The other is that the perceived probability of being infected is positively correlated to individual degrees (preferential case). We show that these two risk assessment systems can yield completely different results, such as, the effectiveness of controlling diseases, the time evolution of the number of infections, and so on.     

Enhanced coercivity in sponge magnets with three dimensionally ordered nanopores

Nanoporous magnets are new promising materials particularly useful in biological assays and ion separations. This letter deals with a simple method for making porous magnets composed of cobalt ferrite, where polymer colloidal spheres were used as sacrificial templates. Compared with the bulk congener the porous cobalt ferrite shows enhancements in coercive field and magnetization, which could be associated with the presence of nanopores ordered three dimensionally. Using the sponge magnet complete removal of magnetic Cu and Fe ions was achieved while partial removal was observed with porous silicate having the same size of nanopores.     

Novel long-pulse TE CO2 laser excited by pulser–sustainer discharge

A novel long-pulse TE CO₂ laser with UV-preionization is presented. With an active volume of 1.17 l and gas pressure of 30 kPa, the laser can discharge stably with low pulser energy and high sustainer energy. Various long-pulse discharges such as 12, 20 or 25 μs are demonstrated. At discharge pulse width of 23.9 μs, maximum output laser energy of 6.8 J is obtained at an efficiency of 9.0%.     

信噪比对偏振耦合测试影响分析

以白光麦克尔逊干涉仪对双折射保偏光纤的偏振耦合进行测试,并基于仪器结构建立了测试扫描结果的数学模型.分析及仿真了信噪比对耦合强度及耦合位置检测的影响大小及变化趋势.信噪比大于32dB,可满足偏振耦合测试的要求.     

可调谐液晶法-珀滤光片的研究

提出了一种可用于密集波分复用系统中的新型可调谐滤光片的设计方法,该设计利用了液晶的双折射现象,以及液晶盒内法-珀效应,从理论上分析了器件的光谱特性,计算了液晶分子的折射率调制和其分子转动角度的关系.并对器件进行了性能测试.实验结果与理论吻合较好.     

类镍等电子系列离子M1,M2,E2禁戒跃迁特性的理论研究

利用基于全相对论框架下的多组态Dirac-Fock理论方法发展起来的程序包GRASP92和新发展的处理辐射跃迁过程的程序REOS99,计算了类镍等电子系列离子(Z=45-95)的基组态3s23p63d10 1S0以及低激发组态3s23p63d94l,3s23p53d104l和3s3p63d104 l(l=s,p,d,f)的能级及其向基态的M1,M2,E2禁戒跃迁概率.通过分析高离化类镍离子在特定的原子序数范围内由于存在能级交叉而产生的强组态相互作用,解释了高离化类镍离子禁戒跃迁概率的反常变化现象,探讨了禁戒跃迁概率受强组态相互作用影响而变化的一般规律.