碳氢扩散火焰实验研究：燃烧气氛对火焰光谱与温度的影响

辐射是各种燃烧过程中热传递的主要方式。在不同的火焰中,辐射光谱分布十分复杂。在这项工作中,利用光谱仪测量了可见光(200～900 nm),近红外(900～1 700 nm)和中红外(2 500～5 000 nm)波段火焰的光谱强度,分析了空气和富氧气氛下扩散火焰的光谱特征。并基于光谱分析,定量得到了火焰中碳烟以及气体发射的辐射力,计算了火焰的温度分布。结果表明,空气燃烧中的火焰温度低于富氧燃烧中的火焰温度。在空气气氛下,火焰中的碳烟和气体均对中的热辐射起着重要作用。而在富氧气氛下,气体对于火焰热辐射更为重要。在可见光和近红外波段,由于在空气气氛下火焰中碳烟的大量形成,光谱曲线显示出了良好连续性。而富氧气氛下火焰的辐射光谱降低。在中红外波段,空气气氛下火焰的气体辐射明显弱于富氧气氛下火焰的气体辐射。     

Investigation of the interaction of DNA and neutral red by?uorescence spectroscopic analysis

The binding characteristics of neutral red (NR) with DNA were investigated by fluorescence spectrometry. Chemometrics approach as singular value decomposition (SVD) was used to evaluate the number of spectral species in the drug-DNA binding process, and then the intrinsic binding constant of 1.6 104 in base pairs and the binding site number of 0.97 were obtained from the Scatchard plot.     

采用BP神经网络研究C-F键核自旋偶合常数

通常理论研究核自旋偶合常数的方法是基于线性模型进行拟合和预测，该方法在拟合和预测中仍有较大误差. 本文在前面工作的基础上，提出了基于非线性模型对C-F键核自旋偶合常数进行研究的观点，采用BP神经网络方法对C-F键核自旋偶合常数的函数关系式进行拟合，并用拟合结果对4种化合物的偶合常数进行预测. 结果表明，采用非线性的BP神经网络方法其训练效果与预测效果均优于线性模型方法；其预测误差对文中的4种化合物不超过0.40%.     

Synthesis and Crystal Structural Characterization of a Thiosemicarbazone Derived from 4-Acylpyrazolone

1 INTRODUCTION Pyrazol-5-one derivatives form an important class of organic compounds due to their structural che- mistry and biological activities as analgesic, antipy- retic, anti-inflammatory and hyperglycemic agents[1～4]. Even the simplest pyrazol-5-one derivatives like antipyrine and amidopyrine are widely used in anal- gesic medicine[5, 6]. On the other hand, thiosemicar- bazones, especially heterocyclic thiosemicarbazones, have been the subject of extensive investigations be- cause…     

Synthesis, Crystal Structure, Fluorescent and Thermal Properties of Sodium Tridecafluorodizirconate Na_5Zr_2F_(13) Compound

1 INTRODUCTION Considerable research effort on the heavy metal fluoride glasses like barium, zirconium fluoride and a series of rare-earth fluorozirconate compounds du- ring the last two decades was initiated by the broad optical transmission window of these glasses and thereby the potential for ultralow-loss optical fi- bers[1~10]. The fluorozirconate of alkali metals was first reported in 1938[11], and most of the sodium and potassium fluorozirconates were reported amongthe 1940s and 19…     

HETEROAROMATIC POLYMERS—HIGH TEMPERATURE POLYPYRROLONES DERIVED FROM 2,6-BIS(3'''',4''''-DIAMINOPHENYL)-4-BIPHENYLPYRIDINE AND VARIOUS AROMATIC DIANHYDRIDES

A new type of aromatic tetraamine containing biphenyl moiety in the side chain was synthesized via a modified Chichibabin's reaction.3-Nitro-4-acetamidoacetophenone was reacted with 4-phenyl benzaldehyde in the presence of ammonium acetate to obtain 2,6-bis(3',4'-diaminophenyl)-4-biphenyl pyridine(DPPA).A series of polypyrrolones(PPys) were prepared using tetraamine and various aromatic dianhydrides via a two-step cyclization procedure.All the PPys show excellent high temperature stabilities with the initial decomposition temperatures of 530-549℃ and residual weight ratio of 49%-80% at 750℃ in nitrogen.The polymers exhibit no apparent glass transition temperatures(T_gs)except PPy-1 (T_g=327℃),which is derived from tetraamine DPPA and 2,2-bis[4-(3',4'-dicarboxyphenoxy)-phenyl]propane dianhydride (BPADA).In addition,the polymers have acceptable mechanical properties with the tensile strength of 65-94 MPa.The PPy films show excellent hydrolysis-resistance in alkaline aqueous medium and could maintain most of the properties even after boiling in 10% aqueous sodium hydroxide solution for a week.     

中药土鳖虫溶栓成分的分离纯化研究

对土鳖虫水浸醇沉提取物2号样品进行了离子交换柱层析，得组分Ⅰ、Ⅱ、Ⅲ。实验结果表明，组分Ⅲ的溶栓活性明显高于组分Ⅰ和组分Ⅱ，其蛋白质占量为88．9％，分子量约为38，018，效价为313UK／mg，比活力为352UK／mg蛋白。将组分Ⅲ再进行凝胶过滤柱层析，得组分Ⅳ、Ⅴ、Ⅵ。组分Ⅵ的生物活性高于组分Ⅳ和组分Ⅴ，蛋白质含量为89．3％，电泳呈现两条带，分子量约为34，623和39，811，效价为77UK／mg，比活力为86UK／mg蛋白。将组分Ⅵ进行反相高效液相色谱柱层析，收集保留时间为17min的洗脱峰，得到土鳖虫纯蛋白质，呈白色絮状，极易溶于水。再一次用反相高效液相色谱检查其纯度，保留时间为17．073min．无杂质峰。纤溶活性实验结果表明，组分Ⅵ既有直接降解纤维蛋白的作用，同时也有纤溶酶原激活剂样作用。     

Photochemical degradation of environmentally persistent perfluorooctanoic acid （PFOA） in the presence of Fe（Ⅲ）

Environmentally persistent and bioaccumulative perfluorooctanic acid （PFOA） was difficult to be decomposed under the irradiation of 254 nm UV light. However, in the presence of 80μmol/L Fe（Ⅲ）, 80% of PFOA with initial concentration of 48μmol/L （20 mg/L） was effectively degraded and 47.8% of fluorine atoms in PFOA molecule were transformed into inorganic fluoride ion after 4 h reaction. Shorter chain perfluorocarboxylic acids bearing C3-C7 and fluoride ion were detected and identified by LC/MS and IC as the degradation products in the aqueous solution. It was proposed that complexes of PFOA with Fe（Ⅲ） initiated degradation of PFOA irradiated with 254 nm UV light.     

两角和与差的三角函数

1．本单元重、难点分析 本单元的重点是：两角和与差的正弦、余弦、正切公式；二倍角的正弦、余弦、正切公式；运用公式进行简单三角函数式的化简、求值与恒等式证明．     

Synthesis and Crystal Structure of the Heteropolymate Compound Na_3H_2[Ce_3(H_2O)_(18)Bi_2W_(22)O_(76)]·23H_2O

1 INTRODUCTION As a rich remarkable class of inorganic cluster systems, polyoxometalates continue to be the focus of significant attention in the 21th century because of their various and alluring topologies as well as their unusual physicochemical prope…