先锋褐煤热溶及热溶物红外光谱表征

利用高温热溶装置研究了不同溶剂中先锋褐煤热溶性能,并对热溶物和热溶残煤分别进行了红外光谱表征。结果表明,先锋褐煤以化学交联大分子结构为主,非共价键缔合低分子化合物含量较低;虽然高温热溶可以显著提高热溶效率,300℃甲苯和四氢萘溶剂中热溶率达到20.7%和21.3%,但是以热断裂煤结构中的非共价键作用,促进低分子化合物溶解为主;300℃热溶过程中不存在明显热解反应,供氢溶剂及氢键型溶剂作用不明显;先锋褐煤热溶物中含有丰富的脂肪结构和羧酸酯,羟基和芳香结构含量较低;热溶溶剂明显影响热溶物结构与组成。
     

磷对CoMoP浸渍液及催化剂活性组分结构影响的激光拉曼光谱法研究

采用激光拉曼光谱技术(LRS)对CoMoP浸渍液以及浸渍后的样品进行表征,研究了磷含量对CoMoP浸渍液中活性相前躯体结构的影响以及在浸渍后处理过程中对活性相结构的影响.实验结果表明,当CoMoP浸渍液中磷含量较低时,活性组分主要以CoxH6-2x[P2Mo5O23]、CoxH7-2x[PMo11O39]或CoxH3-2x[PMo9O31]以及CoxH3-2x[PMo12O40]结构存在,随着磷添加量的增加,后3种结构转化成CoxH6-2x[P2Mo5O23].提高磷含量有利于抑制活性组分在氧化铝表面分解成七聚钼酸盐.活性组分在载体吸附和催化剂焙烧过程中,在Mo和P之间存在相互作用,[P2Mo5O23]6-结构在焙烧过程中会发生解离.干燥样品经过高温焙烧后,催化剂中出现四面体配位和八面体配位的钼物种.     

焦炭与CO2和水蒸气气化后孔隙结构和高温抗压强度研究

通过焦炭气化反应装置和高温抗压强度测定装置,研究了焦炭与CO₂和水蒸气气化后孔隙结构变化规律及溶损率、温度和孔隙结构对焦炭高温抗压强度的影响。结果表明,与CO₂气化相比,水蒸气气化后焦炭平均孔径较小,比表面积和100 μm以下气孔数量增加,且整体高温抗压强度更高。焦炭气化后高温抗压强度随溶损率增加而降低,随温度升高而降低。温度为1 200 ℃时,随溶损率增加压缩过程焦炭承受压缩功(WOC_u)逐渐降低,水蒸气气化后的WOC_u高于CO₂条件,随溶损率增加焦炭压缩过程形变量呈降低趋势。在相同溶损率下,水蒸气气化后焦炭的孔隙结构对焦炭强度损害相对较小,抗变形能力更强。     

热解/红外光谱联用技术用于热解反应的快速检测

详细介绍了快速热解装置CDS2000／红外联用仪(Py／FTIR)的特点。带有样品的热解探头插入并固定在接口装置上，接口装置可直接置于FTIR的光路中，对热解产物进行直接、快速检测，并且可分析重质热解产物。CDS2000热丝裂解器具有极快的升温速度，升温速度从0．01℃／min到20000℃／s，可以有效避免热解过程中的二次反应，有助于推断结构和热解机理；另外，本文对CDS2000／FTIR热解／红外联用仪使用过程中的有关参数进行了分析，如分辨率的选择。本文应用CDS2000／FTIR联用仪对PVC、生物质和模型化合物进行了热解实验，取得了满意的结果。     

二维红外相关光谱在双氰胺固化环氧树脂体系中的应用

利用原位红外加热炉模拟双氰胺固化环氧树脂体系的固化反应过程,实时测试并记录反应过程中官能团结构的变化;将一维红外光谱和二维红外光谱相结合进行分析,给出固化过程中各官能团的变化顺序和趋势。 在双氰胺固化环氧树脂体系中,双氰胺首先分解成氰基胺,然后再和环氧树脂发生开环加成反应,生成亚胺结构,通过重排生成酰胺结构。 双氰胺分解为氰基胺的反应是可逆反应。 将原位红外、一维红外与二维红外三者结合是阐明热固性树脂固化反应机理的非常有效的手段。     

激光光热反射光谱检测装置的研制

研制出一种采用直接测量激光反射光信号的激光光热反射光谱检测装置。讨论了该装置的硬件结构和程序模块,并应用于分子印迹实验。该装置具有操作简单、精度高、稳定性好和抗干扰能力强等优点。     

β-转角肽的溶液构象

主要报导TEM-1β-内酰胺酶的天然蛋白类抑制剂BLIP中一段多肽B1的溶液构象研究 结果.在磷酸盐缓冲溶液中,通过圆二色光谱、傅立叶红外光谱和核磁共振谱研究了B1的二 级结构特征.实验结果表明,B1在溶液中形成了β-转角结构,为在溶液中单独研究β-转 角结构形成与稳定性提供了良好的模板.β-转角在溶液中可以独立存在,表明β-转角在 蛋白质折叠过程中可能具有重要作用.     

时间分辨激光荧光光谱分析技术研究——Ⅱ.微秒级时间分辨激光荧光光谱测量

本文主要以进行稀土元素分析为目的,在已建立的激光荧光寿命测量装置的基础上,建立了时间分辨激光荧光光谱测量装置。结合在此装置上取得的初步实验结果,对装置的原理、特点、使用范围、工作条件进行了讨论。为进行稀土元素的时间分辩激光荧光光谱分析建立了必要的手段,也为某些发光材料的发光动力学研究提供了一定的方法。     

焙烧温度对Ni/MgO催化剂结构及其在甲苯二氧化碳重整反应中催化性能的影响(英文)

考察了焙烧温度对 Ni/MgO 催化剂结构及其在甲苯二氧化碳重整反应中催化性能的影响. 由于 NiO-MgO 固溶体的形成,样品的 X 射线衍射谱中没有出现明显的 NiO 衍射峰, 而在拉曼光谱中出现明显的散射信号. X 射线光电子能谱、氢气程序升温还原和 H2脉冲吸附结果表明, 高温焙烧过程中 Ni 向催化剂体相扩散, 与 MgO 发生强互相互作用, 使得 Ni 物种难以还原,但部分位于催化剂表面的 Ni 物种能够还原; 高温焙烧后催化剂表面活性 Ni 物种明显减少, 致使催化剂重整活性降低. 重整反应后, 催化剂表面存在少量多核芳烃类积炭, 这很可能是高温焙烧催化剂稳定性差的原因.     

水光谱探针及其在结构分析中的应用

水对化学和生物过程具有重要作用,因此水的结构和性质研究一直备受关注。水的结构易受温度影响,利用温控近红外光谱技术和化学计量学方法,通过提取随温度变化的水光谱信息,不仅可以了解水的结构和性质,还可以将水作为探针,探测溶液或生物体系中分子的定量信息和结构变化。该文总结了利用温控近红外光谱技术研究小分子的结构和蛋白质、温敏聚合物结构转变过程等方面的研究工作,并利用随温度变化的水光谱信息,对化学结构及其变化过程中水的作用及作用机理进行了分析。     

Studies on the Lanthanum-Modified Lead Titanate Ultrafine Particles by Raman Spectroscopy

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Thermal Stability and Thermal Behavior of Nanoparticle a-Fe2O3-stearate Alternating Langmuir-BIodgett Multilayer

Thermal stability and thermal behavior of nanoparticulate α-Fe₂O₃-stearate alternating Langmuir-Blodgett multilayer have been studied through temperature dependent FTIR spectroscopy. The results show that this multilayer has an excellent thermal stability. From 60℃ to 150℃,the alkyl chains in the multilayer can keep "all trans" configuration and the Fe₂O₃ nanopar-ticle multilayer film structure still remains an order structure. From 200℃ to 220℃, the film undergoes a phase transition from solid to liquid. Tins high melting point is due to the high molecular weight (at least 105 atomic weight units for one nanoparticle) and the stearate ions are chemically bonded to it.     

Identification of Free OH and its Implication on Structural Changes of Liquid Water

The molecular structure of liquid water has been an outstanding issue for many years. The identification of free -OH holds the key in differentiating structure models for liquid water. By analyzing the relative changes of the intensity and depolarization ratio in temperature dependent Raman spectra, the occurrence of free -OH in liquid water is unambiguously de-termined. Furthermore, upon the increase of temperature from 5 oC to 85 oC, the structure of liquid water undergoes significant change, but the relative proportion of free -OH is con-siderably small and remains almost unchanged. This implies that the breaking of hydrogen bond from the tetrahedral structure prefers to occur at the site of the hydrogen acceptor. The energetic favoring of the structural change for liquid water is thus clearly revealed from experiments.     

Rheological characterization and microphase‐separated structure of a poly(ether‐block‐amide) segmented block copolymer

Melt of a segmented block copolymer having poly(lauryl lactam) as the hard segment and poly(tetramethylene oxide) as the soft segment was investigated by rheological techniques. Storage modulus of the polymer melt exhibits the nonterminal behavior resembling those of diblock and triblock copolymer melts, indicating the existence of a microphase‐separated structure. Contrary to block copolymers, the melt of the segmented block copolymer changes from a weak structure to a stiff one upon raising temperature. The storage modulus of the weak structure at low temperatures is inert to large‐amplitude oscillatory shear, while the oscillatory shear destroys the stiff structure at high temperatures and reduces its storage modulus to a value that is same as that of the weak structure. The tapping‐mode data of atomic force microscopy reveal that at low temperatures the polymer melt exhibits a biphasic structure consisted of small spherical soft domains dispersed in a slightly harder matrix; and at high temperatures the spherical domain structure preserves, though the domain coarsens and the hardness difference between the domain and the matrix enlarges. Infrared spectrum analysis shows that the temperature‐induced structural change is related to the dissociation of hydrogen bonding between the hard and soft segments. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2557–2567, 2005     

Electronic and Spectroscopic Properties of La2@C112 Isomers

Among the 3352 isolated pentagon rule(IPR) isomers and 129073 non-IPR isomers satisfying adjacent pentagon pairs(APPs) ≤ 2 of fullerene C₁₁₂, the lowest-energy IPR and non-IPR isomers of C₁₁₂ and C₁₁₂^6- have been fully screened by the density functional tight-binding(DFTB) and density functional theory(DFT) methods for stu-dying the electronic and spectroscopic properties of La₂@C₁₁₂. The structural features and infrared and absorption spectra of those isomers were analyzed in detail, and the characteristic fingerprint absorption peaks were assigned. To clarify the relative stabilities of La₂@C₁₁₂ isomers at high temperature, entropy contributions were determined at the B3LYP level. IPR isomer La₂@C₁₁₂(C₂:860136) is not the lowest-energy isomer but is one of the most important isomers. This is the first work that considers non-IPR C₁₁₂ isomers when exploring the structure and properties of La₂@C₁₁₂.     

A broad-band dielectric study of poly(vinyl chloride): Effect of molar mass and processing conditions on space-charge mechanisms

The dielectric properties of poly(vinyl-chloride) (PVC) were investigated as a function of frequency and temperature. Attention was focused on the low frequency dielectric properties. Samples with different molar masses were studied. Two dipolar retardation processes were observed, one due to a local motion in the polymeric chain and the other at the glass transition. In compression-molded samples of high molar mass an additional low-frequency space-charge polarization mechanism was found at high temperatures. The effect was most pronounced at the highest molar masses. The space-charge mechanism was absent in samples of well-kneaded material. This macroscopic polarization process in compression molded samples is probably due to discontinuities in the poorly gelified material because of a residual grain particle structure. The detected effects of air inclusions in a PVC matrix can be described by the Maxwell-Wagner theory. The magnitude of the space-charge mechanism is an indication of the effectiveness of the processing method used in destroying the grain structure. © 1994 John Wiley & Sons, Inc.     

Growth, Band Structure and Optical Properties of LiSrBO3 Crystal

The bulk crystal of LiSrBO3 (8.39 g) with a size of 21mm×20mm×15mm was grown by high temperature solution growth method. The relationship between growth habit and crystal structure was discussed. The transmission spectrum shows an UV absorption edge at about 300 nm. The melting temperature of this crystal was determined to be 942 ℃ by DTA-TG measurement. The band structure of the LiSrBO3 crystal was studied by means of the first principle method. An indirect band gap was found to be about 4.0 eV,and a low dielectric constant was estimated to be about 1.9 in terms of theoretical results.     

The Fourier transform infrared spectrum of the boron trifluoride–nitrous oxide complex

The Fourier transform infrared spectra of boron trifluoride and nitrous oxide, co-deposited in nitrogen and argon matrices at cryogenic temperatures, have been recorded. Concentration and temperature cycling experiments have established the existence of a 1:1 molecular complex, the spectrum of which is consistent with a structure similar to that of BF₃.N₂O in the gas phase. The structure derived from the infrared spectrum is also consistent with the results of a series of ab initio molecular orbital calculations reported by us recently. The experimental wavenumbers and complex-monomer wavenumber shifts compare reasonably well, by and large, with those predicted by the ab initio calculations.     

金属氮化物包合物Tb3N@C80的分离和表征

在利用电弧放电法合成铽的富勒烯笼内金属包合物时,首次观察到Tb₃N@C₈₀的存在,并用两步HPLC法将其分离和提纯.进一步的实验结果表明,氮气的加入是导致Tb₃N@C₈₀生成的原因.并用MALDI-TOF-MS和UV-Vis-NIR光谱对其进行了表征.     

离子液体在分析化学中应用研究进展

离子液体具有低蒸汽压、低熔点、宽电化学窗口、良好离子导电性、导热性及高热稳定性等特点,是一种新型的软介质和功能材料。离子液体已经被用于分析化学的各个领域如分离科学、色谱体系、电化学分析与传感器、光谱与质谱等方面。并对室温离子液体在分析化学各个方面的最新应用进展进行了综述。