一种改进的外积分解(OPDA)算法

传统的外积分解(OPDA outer-product decomposition algorithm)算法虽然允许信道阶数被过估计,但该情况下的均衡结果不够理想。针对这一问题,提出一种改进的算法,即对过估计出的信道响应修正后再进行均衡。改进的算法较之原算法能更好的抑制剩余码间干扰,且在阶数估计上有更好的鲁棒性。通过计算机仿真证明了该算法的有效性。

一种基于帧结构的MIMO-OPDA盲均衡改进算法

提出了一种新的改进外积分解法(OPDA),克服了单输入多输出(SIMO)系统中的OPDA盲均衡算法扩展到多输入多输出(MIMO)系统中计算复杂度增加的缺点。在MATALB中构建了基于帧结构的MIMO-OPDA盲均衡算法模型,并将改进算法和原算法进行了仿真比较.仿真表明系统运算速度提高了,而且随着接收信息的累积,改进的OPDA和原OPDA算法性能相当,证明算法改进十分有效。

Fragmentation Reactions of Adduct Ions [M+CH_3CO]^+ of Isomeric Phenylenediamines

The dissociation routes of the adduct ions [M+CH3CO]+ formed by ion-moleculereaction of isomeric phenylenediamines with acetyl ion from acetone under chemical ionizationcondition were investigated by using collision-induced dissociation (CID) technique performed ation kinetic energies of 40eV. The adduct ions are intermediate ion-neutral complexes.

Fast electron transfer and enhanced visible light photocatalytic activity by using poly-o-phenylenediamine modified AgCl/g-C_3N_4 nanosheets

Exfoliation of bulk graphitic carbon nitride(g‐C3N4)into two‐dimensional(2D)nanosheets is one of the effective strategies to improve its photocatalytic properties so that the 2D g‐C3N4 nanosheets(CN)have larger specific surface areas and more reaction sites.In addition,poly‐o‐phenylenediamine(PoPD)can improve the electrical conductivity and photocatalytic activity of semiconductor materials.Here,the novel efficient composite PoPD/AgCl/g‐C3N4 nanosheets was first synthesized by a precipitation reaction and the photoinitiated polymerization approach.The obtained photocatalysts have larger specific surface areas and could achieve better visible‐light response.However,silver chloride(AgCl)is susceptible to agglomeration and photocorrosion.The PoPD/AgCl/CN composite exhibits an extremely high photocurrent density,which is three times that of CN.Obviously enhanced photocatalytic activities of PoPD/AgCl/g‐C3N4 are revealed through the photodegradation of tetracycline.The stability of PoPD/AgCl/CN is demonstrated based on four cycles of experiments that reveal that the degradation rate only decreases slightly.Furthermore,.O2^-and h+are the main active species,which are confirmed through a trapping experiment and ESR spin‐trap technique.Therefore,the prepared PoPD/AgCl/CN can be considered as a stable photocatalyst,in which PoPD is added as a charge carrier and acts a photosensitive protective layer on the surface of the AgCl particles.This provides a new technology for preparing highly stable composite photocatalysts that can effectively deal with environmental issues.

A novel impedance immunosensor based on O-phenylenediamine modified gold electrode to analyze abscisic acid

An impedance immunosensor based on O-phenylenediamine modified gold electrode for the determination of phytohormone abscisic acid(ABA) was proposed.The operating pH,absorption time,absorption temperature and concentration of anti-ABA antibody were investigated to optimize the analytical performance.The calibration curve for the determination of ABA was obtained from this impedance immunosensor under optimal conditions.The results showed that the detection limit at about 1 ng/mL in the range of 10-5000 ng/mL...

Determination and correlation solubility of m-phenylenediamine in (methanol, ethanol, acetonitrile and water) and their binary solvents from 278.15 K to 313.15 K

In this study, the solubility of m-phenylenediamine in four pure solvents(methanol, ethanol, acetonitrile and water) and three binary solvent(methanol + water),(ethanol + water) and(acetonitrile + water) systems were determined in the temperature ranging from 278.15 K to 313.15 K by using the gravimetric method under atmospheric pressure. In the temperature range of 278.15 K to 313.15 K, the mole fraction solubility values of m-phenylenediamine in water, methanol, ethanol, and acetonitrile are 0.0093–0.1533, 0.1668–0.5589,0.1072–0.5356, and 0.1717–0.6438, respectively. At constant temperature and solvent composition, the mole fraction solubility of o-phenylenediamine in four pure solvents was increased as the following order:water b ethanol b methanol b acetonitrile;and in the three binary solvent mixtures could be ranked as follows:(ethanol + water) b(methanol + water) b(acetonitrile + water). The relationship between the experimental temperature and the solubility of m-phenylenediamine was revealed as follows: the solubility of mphenylenediamine in pure and binary solvents could be increased with the increase of temperature. The experimental values were correlated with the Jouyban–Acree model, van’t Hoff–Jouyban–Acree model, modified Apelblat–Jouyban–Acree model, Sun model and Ma model. The standard dissolution enthalpy, standard dissolution entropy and the Gibbs energy were calculated based on the experimental solubility data. In the binary solvent mixtures, the dissolution of m-phenylenediamine could be an endothermic process. The solubility data,correlation equations and thermodynamic property obtained from this study would be invoked as basic data and models regarding the purification and crystallization process of m-phenylenediamine.

A Novel Catalyst for Liquid Phase Hydrogenation of m-Dinitrobenzene to m-Phenylenediamine

A novel lanthana-promoted nickel catalyst supported on silica for the liquid phase hydrogenation of m-dinitrobenzene to m-phenylenediamine was prepared by an incipient wetness sequential impregnation method. It was found that Ni-La/SiO2 catalyst exhibited high activity and stability for m-dinitrobenzene hydrogenation. Over this catalyst, the conversion of m-dinitrobenzene and the yield of m-phenylenediamine were up to 97.1% and 93.5%, respectively, at 373 K and 2.6 MPa hydrogen pressure after reaction for 1 h.

Thermal Degradation Kinetics of N,N'-Di(diethoxythiophosphoryl)-1,4-phenylenediamine

The non-isothermal degradation kinetics of N,N＇-di（diethoxythiophosphoryl）-1,4-phenylenediamine in N2 was studied by TG-DTG techniques.The kinetic parameters,including the activation energy and pre-exponential factor of the degradation process for the title compound were calculated by means of the Kissinger and Flynn-Wall-Ozawa（FWO）method and the thermal degradation mechanism of the title compound was also studied with the Satava-Sestak methods.The results indicate that the activation energy and pre-exponential factor are 152.61 kJ/mol and 9.06×101 4s -1with the Kissinger method and 154.08 kJ/mol with the Flynn-Wall-Ozawa method,respectively.It has been shown that the degradation of the title compound follows a kinetic model of one-dimensional diffusion or parabolic law,the kinetic function is G（α）=α2and the reaction order is n=2.

Theoretical investigation of uranium(Ⅳ) coordinated with N,N'-bis(3-allyl salicylidene)-o-phenylenediamine

We used density functional theory calculations at the B3LYP/6-311G** level for a theoretical study on the complex formed when uranium(Ⅳ) coordinates with N,N'- bis(3-allyl salicylidene)-o-phenylenediamine(BASPDA),i.e.,U(BASPDA)_2.The results indicated that the coordination complex of U(BASPDA)2 could form two different structures with a ratio of 1:2.One was a parallel dislocation structure(PDS-U),in which the two BASPDAs' middle benzene rings adopted a parallel dislocation with an angle of 56.64°,and the other was a staggered finger "+" structure(SFS-U),in which the two BASPDAs employed the staggered finger "+" shape.The binding energies,charge distribution,spectral properties,thermodynamic properties,molecular orbitals and Wiberg bond indices for both PDS-U and SFS-U were calculated and compared with each other.

A New Dinuclear Gadolinium Complex Constructed from p-Phenylenediamine-N,N,N′,N′-tetraacetic Acid and in situ Generated Oxalate

Routine solution reaction of Gd3＋ and p-phenylenediamine-N,N,N′,N′-tetraacetic acid （p-PhDTA） yields a dinuclear complex [Gd2（ox）（p-PhDTA）2（H2O）10]·6H2O （ox = oxalate）, which was characterized by single-crystal X-ray diffraction （MoKα radiation, = 0.71073）, elemental analysis and IR. This complex crystallizes in the monoclinic system, space group P21/n with a = 10.2522（8）, b = 10.0053（8）, c = 23.8834（18）, = 99.1080（10）°, V = 2419.0（3）3, Z = 2, Mr = 1367.32, Dc = 1.877 g/cm3, F（000） = 1368, = 2.830 mm-1, the final R = 0.0337 and wR = 0.0794 for 4747 observed reflections （I 〉 2 （I））. The exo-tetradentate oxalate ligand, generated in situ from the oxidative coupling of methanol, is incorporated to construct a dinuclear Gd2（ox）2 unit decorated with p-PhDTA ligands on the two sides with a monodentate coordination mode. The dinuclear molecules are further connected by the lattice water molecules to form a three-dimen- sional hydrogen network.

Polymerization of o-Phenylenediamine Catalyzed byHemeproteins Encapsulated in Reversed Micelle

Hemeproteins encapsulated in reversed micelle formulated with di-2-ethylhexyl sulfosuccinate(AOT) was found to catalyze the polymerization of o-phenylenediamine(o-PDA) with hydrogen peroxide, whereas o-PDA catalyzed by hemeproteins dissolved in water could only form its trimers. As the nanostructural environment in reversed micelle acts as a certain orientation surrounding medium, it offers a strong electrostatic field that alters the reductive potential of Fe 3+/Fe 2+(E m7) in the heme of hemeproteins and thus increases the catalytic activity of peroxidase accordingly. According to the results of UV-Vis, 1H NMR and FTIR, the polymer catalyzed by hemoglobin(Hb) in reversed micelle was presumed to be constructed of lines and trapeziforms alternatively.

Synthesis and Characterization of a 1-D Zigzag Catenarian Compound [Sn(edt)_2(p-phenylenediamine)]_n

A 1-D zigzag chain [Sn（edt）2（p-phenylenediamine）], （edt=ethane-l,2-thiolate） was synthesized by self-assembly and determined by X-ray structure analysis. The title compound （C10H16N2S4Sn） crystallizes in monoclinic, space group C2/c with a=16.659（2）, b=7.0977（10）, c=12.4421（17） A°,β=96.577（2）°, V= 1461.5（4）A°^3, Z=4, Mr=411.18, Dc=1.869 g/cm^3, F（000）=816,μ=2.300 mm^-1, the final R=0.0332 and wR=0.0837 for 1142 observed reflections （I〉2σ（I））. In the complex, Sn^4＋ ion is six-coordinated with four sulfur atoms of two edt ligands from equatorial positions and two nitrogen atoms of p-phenylenediamine ligands from axial positions. The zigzag chain thus formed is parallel to the a axis.

Green and High Efficient Synthesis of 2-Aryl Benzimidazoles: Reaction of Arylidene Malononitrile and 1,2-Phenylenediamine Derivatives in Water or Solvent-Free Conditions

A fast, high efficiency and environmentally friendly procedure for the synthesis of 2-aryl benzim-idazole derivatives has been reported. Reaction between 1,2-phenylenediamine derivatives and arylidene malononitrile under aqueous media and also solvent-free conditions generates 2-aryl benzimidazole derivatives with a high yield.

<i>In Situ</i>UV–Vis Spectroelectrochemical Studies on the Copolymerization of Diphenylamine and <i>o</i>-Phenylenediamine

The in situ ultraviolet-visible (UV-Vis) spectroelectrochemical study on the copolymerization of diphenylamine (DPA) and o-phenylenediamine (OPD) has been performed at a constant potential of 0.8 V using indium tin oxide (ITO)-coated glass electrodes as working electrode. And also, as a comparison, the electrochemical homopolymerizations of DPA and OPD have been investigated by using the in situ spectroelectrochemical technique. The intermediate species generated during the electrochemical homopoly-merization of DPA and OPD, and the copolymerization of DPA with OPD have been identified by using the in situ spectroelectrochemical procedure. The results reveal the formation of an intermediate in the initial stage of copolymerization through the cross-reaction of the cation radicals of DPA and OPD, and the absorption peak located at 538 nm in the UV–Vis spectra is assigned to this intermediate. To further investigate the copolymerization of DPA with OPD, cyclic voltammetry (CV) has been used to study the electrochemical homopolymerization of DPA and OPD and also the copolymerization of DPA and OPD with different concentration ratios in solution. The different voltammetric characteristics between the homopolymerization and copolymerization processes exhibit the occurrence of the copolymerization, and the difference between the copolymerization of DPA and OPD with different concentration ratios shows the dependence of the copoly-merization on the concentrations of DPA and OPD. The copolymer has also been characterized by Fourier transform infrared spectroscopy (FT-IR).

Urea Amperometric Biosensors Based on Nanostructured Polypyrrole and Poly Ortho-Phenylenediamine

Urea Amperometric biosensor was obtained on the base of nanostructured polypyrrole (PPy) and poly ortho- phenylenediamine (POPDA). The optimal conditions for monomer electropolymerization were determined. The effect of supporting electrolyte and number of deposition cycles on the OPDA and Py electropolymerization were studied. It was proved that POPDA and PPy were affected by pH changes and responded to the ammonium, product of urease catalyzed reaction. SEM images of the modified Pt/PPy electrode were presented. The cycle voltammograms and chrono amperometric curves of Pt/POPDA/urease and Pt/PPy/urease electrodes were studied. A good linear relationship was observed for Pt/POPDA/urease electrode in a concentration range from 6.7 to 54 mMurea. For Pt/PPy/urease electrode the linear relation in the range from 0.02 to0.16 mMurea was determined. The entrapped carbon nanotubes (CNT) in PPy film and the bipolymer layers were prepared for construction of Pt/PPy/CNT/urease, Pt/POPDA/PPy/urease and Pt/PPy/POPDA/urease biosensors. Obviously, the addition of POPDA to the composition of the two biosensors (Pt/PPy/POPDA/urease and Pt/POPDA/PPy/urease) reduced their sensitivity to urea. Pt/РPy/CNT/urease and Pt/РPy/ urease biosensors were 173 and 138 times more sensitive to urea than biosensor without PPy (Pt/POPDA/urease biosensor). It was found, that the performance of Pt/PPy/CNT/urease electrode was the best from the five obtained biosensors: linear range of urea concentrations—from 0.02 to0.16 mM;sensitivity—15.22 μA/mM and detection limit— 0.005 mM urea.

有机磷农药降解酶opdA的提取和酶学性质

采用硫酸铵进行分级沉淀,使有机磷农药降解酶opdA得到了纯化,提纯倍数为2.29,回收率为55.1%,用SDS-PAGE聚丙烯酰胺进行电泳,确定opdA的分子量为35KDa。该酶在温度为25~40℃区间时稳定性良好,35℃时酶活最佳。在pH6~10区间稳定,最适反应pH9。重金属Mg^(2+)、Mn^(2+)对酶活呈现促进作用,而Fe^(2+)、Al^(3+)对酶活抑制作用明显。本文选择5种有机磷农药进行降解试验,降解酶opdA均呈现很好的降解作用。

Fe改性Pt/C催化剂催化混合硝基氯苯氨解产物加氢的研究

使用浸渍-还原法分别制备了3%Pd/C、3%Pt/C和3%Pt-Fe/C催化剂,通过ICP、TEM、XPS等方法对催化剂的金属含量、表面形态、电子状态进行了表征。将制备的催化剂用于以混合硝基氯苯氨解后产物邻、对硝基苯胺和间硝基氯苯为原料,催化加氢合成邻、对苯二胺和间氯苯胺反应。通过对比3种催化剂,得到3%Pt-Fe/C催化剂催化效果最好。以3%Pt-Fe/C为催化剂,考察了各因素对混合硝基氯苯氨解产物加氢反应的影响,确定了反应的最优条件:起始催化剂用量0.8%(以反应原料的质量分数计),m(甲醇)∶m(水)=50∶50为溶剂,温度85℃,压力2 MPa,搅拌转速600 r·min^(-1)。在此条件下,反应物转化率为100%,邻、对苯二胺和间氯苯胺的总收率可以达到99%以上,催化剂可重复使用19次。对新鲜和失活的Pt-Fe/C催化剂进行BET、CO化学吸附、TEM等表征,发现失活后催化剂的比表面积大幅下降,判定催化剂孔道堵塞是导致催化剂失活的主要原因。

植酸/聚间苯二胺修饰纳米SiO_(2)制备水性环氧复合涂层及其防腐性能

以溶胶凝胶法制备了γ-缩水甘油醚氧丙基三甲氧基硅烷(KH560)改性SiO_(2)(f-SiO_(2));将间苯二胺(mPD)原位聚合制备的聚间苯二胺(PmPD)共价接枝在f-SiO_(2)表面,制得(PmPD-SiO_(2));最后,通过分子间作用力将植酸(PA)与PmPD-SiO_(2)结合制得PA/PmPD-SiO_(2)复合材料,用于制备水性环氧复合涂层。采用红外光谱、热失重分析和X射线光电子能谱表征了产物结构,通过扫描电镜、电化学和盐雾试验对涂层的防腐性能进行分析。结果表明,当添加质量分数为0.5%的PA/PmPD-SiO_(2)时,涂层附着力0级、铅笔硬度3H、耐冲击45 kg·cm,缓蚀效率为97.2%,耐腐蚀性最佳;腐蚀电流密度较纯水性环氧树脂(WEP)涂层缩小了36倍,低频阻抗模量较纯WEP涂层提升了2个数量级。

我国对苯二胺类抗氧化剂及其衍生醌类化合物污染现状及健康风险研究进展

对苯二胺类物质(PPDs)通常被用作橡胶工业中的抗氧化剂,以延长橡胶产品(如轮胎)的使用寿命.PPDs的醌类转化产物(PPDQs)近来被视为一类新兴的污染物,因其对一系列水生生物的急性致死毒性而引起广泛关注.PPDs及PPDQs在环境中普遍存在,并可通过多种暴露途径进入人体而对健康造成潜在威胁.本文回顾了目前关于PPDs和PPDQs的来源、浓度和分布的报道,比较不同人群通过各种途径的对PPDs和PPDQs的暴露水平及评估其潜在的健康风险.研究发现,温度、光照、臭氧水平及水文条件等因素影响各环境介质中的PPDs和PPDQs的浓度和分布.此外,人们也普遍暴露于多种PPDs及PPDQs,且PPDQs的内暴露水平比其母体化合物更为严重.现有的流行病学证据表明PPDs和PPDQs可能对人类健康产生不利影响,干扰肝脏和免疫功能,但其毒理学机制尚不清楚.迫切需要开展更多研究以全面了解PPDs和PPDQs对环境和人类健康的影响.

超高效液相色谱-串联高分辨质谱法检测人体尿液中的对苯二胺-醌类新污染物

该文建立了一种基于液液萃取的超高效液相色谱-串联高分辨质谱测定人体尿液中5种新污染物对苯二胺-醌(PPD-Qs)的方法。优化确定了样品前处理条件及色谱、质谱仪器参数,并采用氘代N-(1,3-二甲基丁基)-N'-苯基-对苯二胺醌(6PPD-Q-D5)作为内标进行定量分析。结果表明,该方法在0.01~50 ng/mL范围内线性关系良好,相关系数大于0.999,方法检出限低至2.4~7.5 pg/mL。尿液中5种PPD-Qs的基质效应为81.3%~110%;3种不同浓度水平加标样本的平均回收率为80.5%~114%,日内及日间相对标准偏差(RSD)均不大于11%。将该方法应用于人群队列尿液中5种PPD-Qs的检测,5种PPD-Qs的平均质量浓度为0.04~1.06 ng/mL。该方法操作简单、灵敏度高、重复性好,适用于人体尿液中新污染物PPD-Qs的检测。