2-(2-喹啉偶氮)-1,3-二羟基苯分光光度法测定钒的研究

研究了新显色剂2-(2-喹啉偶氮)-1,3-二羟基苯(QADHB)在阳离子表面活性剂十六烷基三甲基溴化铵(CTMAB)存在下,与钒(V)的显色反应条件。试验结果表明,在pH3.5的柠檬酸-氢氧化钠缓冲介质中,该显色剂可与钒(V)形成2:1 稳定配合物。在550nm波长处配合物的表观摩尔吸光系数ε=7.79×104 L·moL·moL-1·cm-1,钒含量在0-15μg/25mL内符合比尔定律。该法用于几种合金样品中钒的分析,结果令人满意。     

钒—二溴羟基苯基荧光酮——曲通X-100体系显色反应的研究

研究了钒—二溴羟基苯基荧光酮——曲通 X-1 0 0三元配合物的显色反应条件 ,在 p H为 6 .90的 Na H2 PO4 -Na2 HPO4 缓冲液中钒与试剂形成 1∶ 4的配合物 ,其最大吸收波长λmax=5 5 4nm,表观摩尔吸光系数ε=1 .0 5× 1 0 5l· mol- 1· cm- 1,钒的含量在 0～ 9μg/2 5 ml范围内符合比耳定律     

2-(2-喹啉偶氮)-1,3-二羟基苯吸光光度法测定钒的研究

研究了新显色剂2 (2 喹啉偶氮) 1,3 二羟基苯(QADHB)在阳离子表面活性剂十六烷基三甲基溴化铵(CTMAB)存在下,与钒(V)的显色反应条件。试验结果表明,在pH3.5的柠檬酸 氢氧化钠缓冲介质中,该显色剂可与钒(V)形成生成2∶1稳定配合物。在550nm波长处配合物的表观摩尔吸光系数ε=7.79×104L·mol-1·cm-1,钒含量在0～15μg/25mL内符合比尔定律。该法用于几种合金样品中钒的分析,结果令人满意。     

4-硝基-4′-磺酰胺基苯基重氮氨基偶氮苯的合成及其与镉显色反应研究

报道了新显色剂 4 -硝基 - 4′-磺酰胺基苯基重氮氨基偶氮苯的合成及其与 (Ⅱ )显色反应。结果表明 :该试剂能与生成稳定的配合物 ,其配合物的最大吸收波长在 5 2 0nm处 ; (Ⅱ )量在 0～ 9 73μg/ 2 5mL范围内遵守比尔定律 ,表观摩尔吸光系数ε=1 0 4× 10 5L·mol-1·cm-1。用本法测定工业废水中微量 ,结果令人满意     

催化动力学光度法测定痕量钒(Ⅴ)的研究

研究了在 p H=4及没食子酸存在下 ,微量钒 ( )催化溴酸钾氧化邻苯二胺的动力学条件 ,建立了催化动力学光度法测定痕量钒 ( )的新方法。方法的测定范围为 0～ 0 .0 2 5 μg· 2 5 m L- 1 ,检出限为 1.18× 10 - 6 g·L- 1 ,相对标准偏差为 4 .6 3% (n=10 ) ,线性回归方程为△ A=2 5 .6 6 c(μg· 2 5 m L- 1 ) - 0 .0 15 7(r=0 .9997) ,表观摩尔吸光系数ε4 6 0 nm=3.2 7× 10 7L· m ol- 1 · cm- 1 。该法灵敏度高 ,选择性好 ,直接应用于水样和食品样中痕量钒( )的测定 ,结果满意     

5,10,15,20-四(4-甲氧基-3-磺酸苯基)卟啉光度法测定铝合金中痕量锌的研究

5,10,15.20-四(4-甲氧基-3-磺酸苯基)卟啉[T(4-MOP)PS_4],pH5.2,于8-羟基喹啉-5-磺酸存在下,在沸水浴中加热2分钟与 Zn~(2+)形成1:1的配合物。其最大吸收波长位于423.6nm,摩尔吸光系数ε=5.15×10~5l·mol~(-1)·cm~(-1)。是目前测定锌的最灵敏的显色剂之一。用于铝合金中痕量锌的光度测定,结果满意。测定范围为0～2μg/25ml。相关系数γ=0.9995。     

试剂6-硝基-2-苯并噻唑重氮氨基偶氮苯的合成并用其测定人发中的微量锌

在TritonX 1 0 0表面活性剂存在下 ,研究了 6 硝基 2 苯并噻唑重氮氨基偶氮苯 (NBTDAA)与锌的显色反应。在pH1 0 5～ 1 2 0的Na2 B4O7 NaOH缓冲溶液中 ,锌与该试剂生成 1∶4型深红色配合物。配合物的最大吸收峰位于λ =5 2 5nm处 ,表观摩尔吸光系数 1 5 1× 1 0 5L·mol-1 ·cm-1 。Zn2 + 的浓度在 0～ 1 0 μg/ 2 5mL范围内符合比尔定律。用拟定方法测定人发中的微量锌 ,结果满意     

锌(Ⅱ)与2-吡咯硫代甲酸配合物的合成及晶体结构

合成了锌 (Ⅱ )与 2 吡咯硫代甲酸的配合物 [Zn(S2 CC4H4N) 2 ]2 。用X 射线单晶衍射测定了该配合物的晶体结构。结果表明 ,配合物为三斜晶系 ,空间群P1 - ,a =0 80 34(1 5 )nm ,b =0 80 34(1 5 )nm ,c =1 2 31 (2 )nm ,α =73 5 8(3)° ,β =73 5 8(3)° ,γ =87 2 8(2 )° ,Z =2 ,V =0 731 (2 )nm3 ,Dc =1 5 90g/cm3 ,F(0 0 0 ) =35 2 ,R1 =0 0 6 1 0 ,wR2 =0 1 0 5 5。锌原子为畸变的四面体构型 ,由于两个硫代羧酸基的桥联作用 ,配合物以环状结构存在     

新显色剂4-(2-吡啶偶氮)-邻苯二酚吸光光度法测定微量Cd(Ⅱ)

研究了新显色剂4-(2-吡啶偶氮)-邻苯二酚(PAPC)与Cd(Ⅱ)的显色反应。在有机溶剂DMF及pH=10.08Na_4B_4O_7-NaOH缓冲溶液中,试剂与Cd(Ⅱ)反应生成稳定的橙色配合物,其最大吸收波长为498nm,表观摩尔吸光系数为4.9×10~5L·mol~(-1)·cm~(-1),镉含量在0～3.5×10~(-6)mol·L~(-1)范围内服从比耳定律,该方法应用于长江水与自来水中微量镉的测定,结果令人满意。     

5-溴吡啶偶氮-H的合成及应用研究

报道了新试剂 5 -溴吡啶偶氮 -H的合成方法及其与 Cu2 + 显色反应的条件。实验表明 :在弱酸性溶液中 Cu2 + 与试剂形成蓝色配合物 ,K=8.0× 1 0 7,ε=2 .5× 1 0 4L· mol- 1· cm- 1。试剂选择性好 ,应用于岩石矿样中微量铜的测定 ,结果满意     

Victrex® poly(ethersulfone) (PES) and Victrex® poly(etheretherketone) (PEEK)

Properties of two high performance engineering thermoplastics, amorphous polyethersulfone (PES) and semicrystalline polyetheretherketone (PEEK), are discussed. Both resins can be processed by conventional techniques, compounded with high performance fibers, and have high service temperature (up to 300°C). Due to the amorphous character PES can be dissolved and spray coated into metals.     

Photopyroelectric Spectroscopic Studies of ZnO-MnO(2)-Co(3)O(4)-V(2)O(5) Ceramics

Photopyroelectric (PPE) spectroscopy is a nondestructive tool that is used to study the optical properties of the ceramics (ZnO + 0.4MnO(2) + 0.4Co(3)O(4) + xV(2)O(5)), x = 0-1 mol%. Wavelength of incident light, modulated at 10 Hz, was in the range of 300-800 nm. PPE spectrum with reference to the doping level and sintering temperature is discussed. Optical energy band-gap (E(g)) was 2.11 eV for 0.3 mol% V(2)O(5) at a sintering temperature of 1025 °C as determined from the plot (ρhυ)(2)versushυ. With a further increase in V(2)O(5), the value of E(g) was found to be 2.59 eV. Steepness factor 'σ(A)' and 'σ(B)', which characterize the slope of exponential optical absorption, is discussed with reference to the variation of E(g). XRD, SEM and EDAX are also used for characterization of the ceramic. For this ceramic, the maximum relative density and grain size was observed to be 91.8% and 9.5 μm, respectively.     

(Ba_(1-α)Sr_α)_(4.8)(Sm_(0.7)La_(0.3))_(8.8)Ti_(18)O_(54)陶瓷的微波介电性能

采用固相合成法制备了(Ba(1-α)Srα)4.8(Sm0.7La0.3)8.8Ti18O54(α=0.1～0.5)系陶瓷,表征了该陶瓷的相组成和显微结构,测试了微波介电性能.结果表明:α=0.3时,(Ba(1-α)Srα)4.8(Sm0.7La0.3)8.8Ti18O54系陶瓷为单相的新钨青铜结构固溶体.α>0.3时,相继出现了第二相BaLa2Ti4O12和La0.66TiO2.993.随α的增加,(Ba(1-α)Srα)4.8(Sm0.7La0.3)8.8Ti18O54系陶瓷的相对介电常数(εr)先增大后有所波动,品质因数(Qf)先增大后减小,谐振频率温度系数(τf)单调减小.α=0.3时,在1 350℃烧结的陶瓷的微波介电性能最佳:εr=98.77,Qf=5184GHz,τf=10.9×10-6/℃,优于不掺杂的BaO-Sm2O3-TiO2陶瓷的.     

Calcium silicate hydrate (II) (“C-S-H(II)”)

This semicrystalline phase, originally named ‘calcium silicate hydrate(II)’ by Taylor (1950), has been studied with X-rays, electron optics, chemical investigation of silicate anion type, infrared spectra, and thermal methods. It is structurally related to jennite (C₉S₆H₁₁) and probably also to the fibrous CSH of cement pastes, the three phases forming a sequence of decreasing crystallinity. The specimen studied had approximate composition C₂SH_3.2 after standing over saturated CaCλ₂ at about 15°C. CSH(II) contains metasilicate chains and pyrosilicate groups and has a disordered layer structure. Much of the water can be lost reversibly without significant change in lattice parameters.     

Poly(butadiene-acrylic acid(g)acrylonitrile(g)acrylic acid)

Summary In the present work we describe, the synthesis and characterization of a new gel obtained by crosslinking a cooligomer of butadiene-acrylic acid (BuAA), by reaction with acrylonitrile and acrylic acid. The purified product was characterized by FTIR, elemental analyses and scanning electronic microscopy. The thermal properties were studied and swelling indexes were determined in different solvents and at different pH values. The capacity of poly(butadiene-acrylic acid(g)acrylonitrile(g)acrylic acid) [gel A] to separate different organic substances, such as amino acids and colorants, was determined.     

Photooxidative stability of substituted poly(phenylene vinylene) (PPV) and poly(phenylene acetylene) (PPA)

The addition of side groups to improve the photooxidative stability of polymers used in polymer-based light-emitting diodes (LEDs) is explored. Infrared spectroscopy and computational chemistry techniques are used to study the effects of chemical substitution of the reactive vinylene moiety in poly(phenylene vinylene) (PPV). The bond order of the vinylene group in small oligomers is calculated using semiempirical techniques to assess the improvement in stability toward oxidants such as singlet oxygen. We find that PPV dimers allow relative comparisons across a range of possible substitutions. Experimental results correlate well with these calculations. The addition of electron-withdrawing substituents, such as nitrile groups, to the vinylene moiety is found to be particularly effective in reducing the reactivity of alkoxy-substituted PPV toward singlet oxygen. The photooxidative stability of a poly(phenylene acetylene) (PPA) derivative is also studied. It appears that this family of polymers is more stable toward photooxidation than are its PPV analogs. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 2451–2458, 1998     

Chemical cross-linking of conducting poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) using poly(ethylene oxide) (PEO)

Hybrid films of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) were prepared with different molecular weights of poly(ethylene oxide) (PEO). The cross-linking reaction between PEO and PEDOT:PSS was performed at high temperature and confirmed by using differential scanning calorimeter (DSC), contact angle measurement, and solid-state ¹H NMR. The effect of chemical reaction on the conductivity and morphology of these hybrid films was studied by using 4-point probe and atomic force microscope (AFM), respectively. As-spun PEO/PEDOT:PSS films have lower electric conductivity due to the addition of nonconductive PEO, and exhibits no molecular weight dependence on conductivity. After chemical cross-linking reaction at high temperature, only PEDOT:PSS films with lowest molecular weight PEO additives show enhanced conductivity with increasing reaction time. AFM result indicates that the heat-treated PEO/PEDOT:PSS hybrid films show grain-like morphology compared to ethylene glycol treated PEDOT:PSS films which shows continuous PEDOT domain. In the present work we demonstrate that the cross-linking reaction can be used to improve the wet stability of PEDOT:PSS nanofiber, showing good water resistance and excellent dimensional stability.     

Thermal studies of blends of poly(phenylene sulfide) (PPS) with poly(phenylene sulfide sulfone) (PPSS) and with poly(phenylene sulfide ether) (PPSE)

The miscibilities of poly(phenylene) sulfide/poly(phenylene sulfide sulfone) (PPS/PPSS) and poly(phenylene) sulfide/poly(phenylene sulfide ether) (PPS/PPSE) blends were invesigated in terms of shifts of glass transition temperatures T_g of pure PPS, PPSS, a dn PPSE. The crystallization kinetics of PPS/PPSS blends was also studied as a function of molar composition. The PPS/PPSS and PPS/PPSE blends are respectively partially and fully miscible. PPSE shows a plasticizing effect on PPS as does PPS on PPSS, which necessarily improves te processibility in the respective systems. We can control T_g and melting temperature T_m of PPS by varying amounts of PPSE in blends. The melt crystallization temperature T_mc of PPS/PPSE blends was higher than that of the PPSE homopolymer. Therefore, these blends require shorter cycle times in processing than pure PPSE. The overall rate of crystallization for PPS/PPSS blends follows the Avrami equation with an exponent ?2. The maximal rate of crystallization for PPS/PPSS blends occurs at a temperatre higher by 10°C than that for PPS, while the crystallization half time t_1/2 is 4 times shorter. In the cold crystallization range, crystal growth rates increase and Avrami exponents decrease significantly as the temperature increases.