大鼠脑组织含磷代谢物随年龄变化的NMR研究

随着人口老龄化的不断加剧,衰老相关疾病已成为全球关注的问题.神经系统功能的退行性改变居于衰老相关疾病的首位,其机制尚不明了.该文旨在通过核磁共振磷谱(~(31)P NMR)检测不同月龄大鼠脑组织中小分子物质的改变,明确能量相关的含磷化合物随大鼠年龄增长的变化,从而揭示脑组织中年龄相关代谢物的变化规律.该研究萃取了不同年龄(幼年、中年及老年)Sprague-Dawley(SD)大鼠脑组织中的小分子物质,进行了~(31)P NMR检测分析.结果显示:老年大鼠脑组织中能量代谢相关物质——磷酸肌酸的含量显著升高,而磷脂酰胆碱及磷酸肌醇含量显著降低,并且出现了磷酸化葡萄糖.这一发现有助于理解衰老相关的脑结构和功能下调,为神经退行性疾病的发生提供依据.     

Hollow glass microspheres coated with CoFe2O4 and its microwave absorption property

Spinel CoFe₂O₄ coating on the surface of hollow glass microspheres of low density was synthesized by co-precipitation method. The phase structures, morphologies, particle size, shell thickness, chemical compositions of the composites have been characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and energy dispersive X-ray spectroscopy (EDS). The results show that CoFe₂O₄ coating on hollow glass microspheres can be achieved, and the coating layers are constituted by CoFe₂O₄ nanoparticles of mean size ca. 10 nm. The as-synthesized powder materials were uniformly dispersed into the phenolic cement, then the mixture was pasted on metal plate with the area of 200 mm×200 mm as the test plate. The test of microwave absorption was carried out by the radar-absorbing materials (RAM) reflectivity far field radar cross-section (RCS) method. The results indicate that the coated CoFe₂O₄/hollow glass microspheres composites can be applied in lightweight and strong absorption microwave absorbers.     

双折射调谐器设计的等色图原理

提出双折射调谐器设计的等色图方法，给出原理。分析表明当晶片光轴处在以折射光线为轴线、顶角为４５°的圆锥面上时，双折射调谐器具有最快的波长调谐速率；当光轴位于过折射光线并与入射面成４５°或１３５°的平面内时，调谐器抑制非所需波长的能力最强。由此给出光轴相对晶片表面的两个优化取向，对石英晶片它们分别为１８．７１２°和５９．９２２°。文中还给出了三块晶片组合的调谐器的设计例子，对其调谐特性进行了简要的讨论。     

Linearization of Systems of Nonlinear Diffusion Equations

We investigate the linearization of systems of n-component nonlinear diffusion equations; such systems have physical applications in soil science, mathematical biology and invariant curve flows. Equivalence transformations of their auxiliary systems are used to identify the systems that can be linearized. We also provide several examples of systems with two-component equations, and show how to linearize them by nonlocal mappings.     

Study on improving output capability of high-power lasers providing short pulses by using different laser glasses together in the amplifier chain

We have discussed the optical and laser properties of different laser glass types. According to the properties of the gain and the B integral in the high-power laser amplifier chain, an optimal configuration is pointed out to improve the output capability at short pulses based on reducing nonlinear refractive index n₂. In this way, high gain glasses and low n₂ glasses are used in different amplifier stages simultaneously. The simulated results show that on the condition that the maximal output energies of both the configurations are same at 3 and 5 ns, the maximal output capability growth ratio of 30.48% () and 42.24% () for the optimal configuration can be obtained at 1 ns, respectively.     

甲氧氯普胺和盐酸普鲁卡因顺序注射光谱研究和测定

在酸性介质中,铈(Ⅳ)与甲氧氯普胺和盐酸普鲁卡因反应生成不稳定的红色产物,研究了不同条件下的光谱吸收曲线,初步探讨了反应机理,并据此建立了顺序注射光度法测定甲氧氯普胺和盐酸普鲁卡因的新方法。测定甲氧氯普胺方法的线性范围9.71～116.6 μg·mL-1,检出限6.5 μg·mL-1,进样频率45 h-1。测定盐酸普鲁卡因的方法的线性范围10.0～130.0 μg·mL-1,检出限7.4 μg·mL-1,进样频率45 h-1。用于针剂和胃复安药片中甲氧氯普胺的含量以及针剂中盐酸普鲁卡因含量的测定,并与标准测定方法对照,经统计学处理无显著性差异,结果满意。     

溶液样品温度对ICP光源发射强度的影响

通过光电检测法研究了溶液样品温度在20,40和60 ℃条件下,对电感耦合等离子体(ICP)光源发射强度的影响。实验结果表明,随着溶液温度的提高,元素钡、铜和锌的谱线强度有明显的增强。观察了在不同溶液温度下,谱线强度随光源观察高度和载气压力的变化规律, 发现温度的提高使最佳观测高度位置降低,而最佳载气压力升高。     

New Operator Identities and Combinatorics Studied by Virtue of IWOP Technique

Using the coherent state representation we derive some new operator identities and study some mathematical relations in combinatorics. The technique of integral within an ordered product (IWOP) of operators plays an essential role in realizing our goal.     

Second-harmonic generation in thermally poled chalcohalide glass

Second-harmonic generation in 60GeS(2)-20Ga(2)S(3)-20KBr chalcohalide glass was investigated by the thermal poling method. A large second-order nonlinear susceptibility, as high as 7.0 pm/V, was obtained in a poled sample by Maker fringe analysis. We believe this to be the first time that a clear second-harmonic wave was observed in chalcohalide glasses containing large amount of alkali ions (6.25 at. %). Such observation is of great potential use in all optical waveguide devices.     

Influence of binding energies of electrons on nuclear mass predictions

Nuclear mass contains a wealth of nuclear structure information, and has been widely employed to extract the nuclear effective interactions. The known nuclear mass is usually extracted from the experimental atomic mass by subtracting the masses of electrons and adding the binding energy of electrons in the atom. However,the binding energies of electrons are sometimes neglected in extracting the known nuclear masses. The influence of binding energies of electrons on nuclear mass predictions are carefully investigated in this work. If the binding energies of electrons are directly subtracted from the theoretical mass predictions, the rms deviations of nuclear mass predictions with respect to the known data are increased by about 200 ke V for nuclei with Z, N 8. Furthermore, by using the Coulomb energies between protons to absorb the binding energies of electrons, their influence on the rms deviations is significantly reduced to only about 10 ke V for nuclei with Z, N 8. However, the binding energies of electrons are still important for the heavy nuclei, about 150 ke V for nuclei around Z = 100 and up to about 500 ke V for nuclei around Z = 120. Therefore, it is necessary to consider the binding energies of electrons to reliably predict the masses of heavy nuclei at an accuracy of hundreds of ke V.