超高效液相色谱-串联质谱法测定畜禽毛发中利巴韦林及其代谢物

建立了一种测定畜禽毛发中利巴韦林及其代谢物1H-1,2,4-三氮唑-3-甲酰胺(TCONH2)残留的检测方法。1%十二烷基硫酸钠清洗毛发,2%甲酸-甲醇(2:98,V/V)溶液提取,13C-利巴韦林(13CRBV)内标法定量,乙二胺-N-丙基硅烷(PSA)和十八烷基硅烷(C18)基质分散净化,Agilent ZORBAX SB-Aq色谱柱分离,电喷雾串联质谱多反应监测模式测定。利巴韦林和TCONH2在毛发中线性关系良好(R^2>0.99)在2,10,100μg/kg3个添加水平下利巴韦林和代谢物TCONH2的回收率分别为101.5%~108.5%和98.5%~101.5%相对标准偏差均小于7%,检出限和定量限分别为0.2μg/kg和0.5μg/kg。该方法适合于畜禽毛发中违禁抗病毒药物利巴韦林及其代谢物TCONH2的测定。     

对比生物体系以及合成体系中单核铜氧物种对碳氢键和氧氢键活化的理论研究展望

由于具有较好的催化性能,含过渡金属的酶一直备受研究者的关注.其中,铜作为生物体中含量仅次于铁和锌的过渡金属,在新陈代谢过程中发挥着重要作用.铜酶广泛存在于自然界中,该类生物大分子涉及电子转移、氧化还原、氧气的运输与活化等生物化学过程.多种铜酶在氧气活化方面表现出引人注目的 性质,例如:颗粒状甲烷单加氧酶(pMMO)、多...     

替考拉宁和万古霉素高效液相色谱手性固定相的研究

分别使用四种不同的方法将替考拉宁和万古霉素键合在硅胶表面,制备了八种不同的高效液相色谱柱固定相,并在反相模式和极性有机相模式下考察了这八种手性柱的性能.实验表明,固定相制备方法的不同和色谱条件的改变对色谱柱拆分性能有一定的影响,不相同的键合臂,能拆分的对映异构体可能不一样,这些柱之间具有一定的互补性.八种手性固定相均有...     

Synthesis of polysilisiquioxane used as core layer material of optical waveguide

Colorless and transparent polysilisiquioxane was synthesized using non-hydrolytic sol–gel process. A high degree of poly-condensation and a lower remnant ratio of Si–OCH₃ were calculated by ²⁹Si NMR and ¹H NMR, respectively. After spin-coating, subsequently UV and thermal curing, free-cracked thin films were obtained. The properties of the free-cracked thin films were measured by a prism coupler and thermal analysis system. The refractive index increased to 1.5495 (1,310 nm TE) and 1.5468 (1,550 nm TE), respectively, with the increasing of phenyltrimethoxysilane content to 20 mol%. Birefringence was below 0.0005. The thermo-optic coefficient was about −2.8 × 10⁻⁴ °C⁻¹. The optical loss was 0.20 dB cm⁻¹ at 1,310 nm and 0.75 dB cm⁻¹ at 1,550 nm, which was very important for core layer material of optical waveguide. The results of Thermo-Gravimetric Analysis indicated an excellent thermal stability. All of these properties imply that it will be a promising core layer material of optical waveguide.     

Long time behavior of stochastic {MHD} equations perturbed by multiplicative noises

In this paper, 2-dimensional (2D) magnetohydrodynamics (MHD) equations perturbed by multiplicative noises in both the velocity and the magnetic field is studied. We first considered the stability, or the upper semi-continuity, for equivalent random dynamical systems (RDS), and then applying the abstract result we established the existence and the upper semi-continuity of tempered random attractors for the stochastic MHD equations. This result shows that the asymptotic behavior of MHD equations is stable under stochastic perturbations.     

关于可解李三超系

给出了关于李三超系的一些基本概念和性质,包括:(1)可解李三超系的任意包络李超代数都是可解的;(2)如果一个李蔓超系有可解的包络李超代数,则它也是可解的;(3)一个李三超系T是幂零的当且仅当它的标准嵌入李超代数L(T)是幂零的;(4)L(T)的中心等于T的中心;(5)李三超系上的右不变超对称双线性型可唯一地扩张到它的标准嵌入李超代数上.     

Levenberg–Marquardt method based on probabilistic Jacobian models for nonlinear equations

In this paper, we propose a Levenberg–Marquardt method based on probabilistic models for nonlinear equations for which the Jacobian cannot be computed accurately or the computation is very expensive. We introduce the definition of the first-order accurate probabilistic Jacobian model, and show how to construct such a model with sample points generated by standard Gaussian distribution. Under certain conditions, we prove that the proposed method converges to a first order stationary point with probability one. Numerical results show the efficiency of the method.

     

Construction of many- particle spin entangled states and signature

Using the collective rotational transformation,R _x(π we construct two types of many-particle spin entangled states in terms of the bases of angular momentum uncoupling and coupling representations. The concept of signature is introduced. The entanglement properties of a four-particle system is investigated by analyzing various subsystem reduced density matrices.     

Tailoring the d‐Band Centers Enables Co4N Nanosheets To Be Highly Active for Hydrogen Evolution Catalysis

Endowing materials with specific functions that are not readily available is always of great importance, but extremely challenging. Co₄N, with its beneficial metallic characteristics, has been proved to be highly active for the oxidation of water, while it is notoriously poor for catalyzing the hydrogen evolution reaction (HER), because of its unfavorable d‐band energy level. Herein, we successfully endow Co₄N with prominent HER catalytic capability by tailoring the positions of the d‐band center through transition‐metal doping. The V‐doped Co₄N nanosheets display an overpotential of 37 mV at 10 mA cm^?2, which is substantially better than Co₄N and even close to the benchmark Pt/C catalysts. XANES, UPS, and DFT calculations consistently reveal the enhanced performance is attributed to the downshift of the d‐band center, which helps facilitate the H desorption. This concept could provide valuable insights into the design of other catalysts for HER and beyond.