Study on Rhizoma Chuanxiong based on capillary electrophoresis with amperometric detection

<正>A high-performance capillary electrophoresis with amperometric detection(CE-AD) method has been developed for the analysis of seven bioactive ingredients,namely ferulic acid(FA),vanillin,vanillic acid,p-hydroxybenzoic acid,caffeic acid,gallic acid and protocatechuic acid,in Rhizoma Chuanxiong.The effects of several factors such as the acidity and concentration of running buffer,the separation voltage,the applied potential to working electrode and the injection time were investigated.Under the optimum conditions,the seven analytes could be well separated within 21 min at the separation voltage of 16 kV in a 60 mmol/L borax running buffer(pH 8.7).A 300μm diameter carbon disk electrode has a good response at potential of +950 mV(vs.SCE) for all analytes.Good linear relationship was established over three orders of magnitude with detection limits(S/N = 3) ranged from 3.3×10~(-7) to 6.7×10~(-9)g/mL.This proposed method has been successfully applied for the determination and comparison of different batches of Rhizoma Chuanxiong samples based on their characteristic electrochemical profiles.     

Actuator saturation control of uncertain structures with input time delay

This paper presents a robust saturation control approach for active vibration attenuation of building structures involving parameter uncertainties and input time delay. The parameter uncertainties are described in both polytopic and norm-bounded forms and represent the variations of floor masses, stiffnesses and damping coefficients. The input time delay can be time-varying within a known bound. In terms of the feasibility of certain delay-dependent linear matrix inequalities (LMIs), a state feedback controller can be designed to guarantee the robust stability and performance of the closed-loop system in the presence of parameter uncertainties, actuator saturation, and input time delay. The effectiveness of the proposed approach is investigated by numerical simulations on the vibration control of a three-storey building structure subject to seismic excitation. It is validated that the designed robust saturation controller can effectively suppress the structural vibration and keep the system stability when there are parameter uncertainties and input time delay.     

一类参数未知混沌系统的追踪控制与参数辨识

针对一类参数未知的混沌系统,提出一种追踪控制方法,基于Lyapunov稳定性理论,设计了追踪控制器和参数自适应控制律,实现了混沌系统的追踪控制和未知参数的辨识.以统一混沌系统为例进行了数值模拟,结果表明了该方法的有效性. 关键词： 混沌系统 追踪控制 参数辨识     

Synthesis and characterization of green to orange electroluminescent copolymers derived from fluorene and 2,3-dimethylnaphthalopyrazine

Series of high molecular weight, readily soluble copolymers were synthesized by Suzuki palladium catalyzed coupling reaction from 9,9-dioctylfluorene and 2,3-dimethylnaphthopyrazine. The absorption, electrochemical and photoluminescence properties of the copolymers were studied. The external electrolu-minescence efficiencies in the devices of configuration indium-tin oxide/polyethylenedioxythiophene-polystyrene sulfonic acid/poly(fluorene-naphthopyrazine)/barium/aluminium varied with the copolymers composition, and the electroluminescence emission peaks of the copolymers were red-shifted from 530 nm to 584 nm as 2,3-dimethylnaphthopyrazine mole contents increasing from 0.5% to 30%. The best device performance was observed for devices fabricated with the copolymer of 2,3-dimethylnathphpyrazine 5% mole contents, showed maximum external quantum efficiency of 1.38% and electroluminescence peaks at around 537 nm.     

Synthesis of 14-Bromo and 14-Hydroxy Baccatin III Derviatives

Numerous efforts towards synthesis of anticancer drug paclitaxel (Taxol(r), 1a) with improved activities led to the modification at 13-phenylisoserine side chain and different positions of its core structure-baccatin III 1c1. At the same time, the activities of searching new taxoids for starting materials of new semi-synthetic paclitaxel analogs from Taxus spp. plant have not ever been stopped. Among these taxoids, 14?-hydroxy-10-deacetylbaccatin III 22 and 13-acetyl-9-dihydrobaccatin III …     

Oxide-supported Ir nanodendrites with high activity and durability for the oxygen evolution reaction in acid PEM water electrolyzers

Reducing the noble-metal catalyst content of acid Polymer Electrolyte Membrane (PEM) water electrolyzers without compromising catalytic activity and stability is a goal of fundamental scientific interest and substantial technical importance for cost-effective hydrogen-based energy storage. This study presents nanostructured iridium nanodendrites (Ir-ND) supported on antimony doped tin oxide (ATO) as efficient and stable water splitting catalysts for PEM electrolyzers. The active Ir-ND structures exhibited superior structural and morphological properties, such as particle size and surface area compared to commercial state-of-art Ir catalysts. Supported on tailored corrosion-stable conductive oxides, the Ir-ND catalysts exhibited a more than 2-fold larger kinetic water splitting activity compared with supported Ir nanoparticles, and a more than 8-fold larger catalytic activity than commercial Ir blacks. In single-cell PEM electrolyzer tests, the Ir-ND/ATO outperformed commercial Ir catalysts more than 2-fold at technological current densities of 1.5 A cm^–2 at a mere 1.80 V cell voltage, while showing excellent durability under constant current conditions. We conclude that Ir-ND/ATO catalysts have the potential to substantially reduce the required noble metal loading, while maintaining their catalytic performance, both in idealized three-electrode set ups and in the real electrolyzer device environments.     

A novel strategy for in situ maskless synthesis of biochips： Self-driving micro-fluid porous type printing （SMPTP）

A novel maskless technique,self-driving micro-fluid porous type printing(SMPTP),was reported to in situ synthesize oligonucleotide arrays on glass slide,which has the merits of low cost,high quality and simple craft.In SMPTP for fabricating gene- chips,porous fiber tubes with a number of nanometric or micron channels functioned as“active letters”and were assembled in designed patterns,which are identical to the distribution of monomers in each layer of the array,and four patterns were needed for each layer.By means of capillarity,the synthesis solution was automatically taken into porous tubes assembled in a printing plate and reached the surface.An oligonucleotide array of 160 features with four different 15-mer probes was in situ synthesized using this technique.The four specific oligonucleotide probes,including the matched and the mismatched by the fluorescent target sequence,gave obviously different hybridization fluorescent signals.     

金属-聚哇烷-硅结构的电容-电压特性

设计了metal-polysilane-silicon(MPS)结构.首次发现MPS结构具有电容-电压(C-V)特性,许多MPS结构的C-V曲线平带电压为正,且其C-V特性与聚硅烷枝化度一致,即随着聚硅烷枝化度提高,MPS结构C-V曲线明显向电压轴正向漂移.聚硅烷MPS结构有望设计成测定聚硅烷枝化度装置.     

THE METHOD OF THE RECIPROCAL THEOREM OF FORCED VIBRATION FOR THE ELASTIC THIN RECTANGULAR PLATES(Ⅰ)-RECTANGULAR PLATES WITH FOUR CLAMPED EDGES AND WITH THREE CLAMPED EDGES

In this paper the method of the reciprocal theorem (MRT) is extended to solve the steady state responses of rectangular plates under harmonic disturbing forces. A series of the closed solutions of rectangular plates with various boundary conditions are given and the tables and figures which have practical value are provided. MRT is a simple, convenient and general method for solving the steady state responses of rectangular plates under various harmonic disturbing forces. The paper contains three parts: (I) rectangular plates with four clamped edges and with three clamped edges; (II) rectangular plates with two adjacent clamped edges; (III) cantilever plates. We are going to publish them one after another.