配合物La（C5O3H3）3·C12H8N2·H2O的合成和表征

本以α－呋喃甲酸（Ｃ５Ｏ３Ｈ４）和邻菲罗啉（Ｃ１２Ｈ８Ｎ２）为配体,在乙醇８溶剂中与硝酸镧反应,合成了与稀土离子Ｌａ（Ⅲ）的三元混配配合物。经元素分析确定其配合物的组成为Ｌａ（Ｃ５Ｏ３Ｈ３）·Ｃ１２Ｈ８Ｎ２·Ｈ２Ｏ,同时还通过了ＩＲ、＾１ＨＮＭＲ、ＵＶ、ＴＧ－ＤＴＡ等谱光的测试与分析,表征了配合物的组成结构和性质。ＩＲ、＾１ＨＮＭＲ和ＵＶ谱的分析结果表明配体羧酸是以脱质子的酸根形式与中心稀土离子     

一个灵敏测定过氧化氢的吖啶红共振散射光谱新方法

在pH为5.0的HAc-NaAc缓冲液中,Fe2 催化H2O2产生·OH,·OH氧化I-为I2.过量I-与I2反应生成的I-3,与吖啶红(AR)形成AR-I3缔合物分子.在疏水作用和分子间力作用下,AR-I3缔合物分子自动聚集形成(AR-I3)n缔合物微粒.该缔合物微粒在320,400,595 nm处产生3个共振散射峰.H2O2的浓度在0.50～16.0×10-6 mol·L-1范围内与400 nm波长的共振散射光强度成线性关系,方法的检出限为2.0×10-7 mol·L-1 H2O2,用于废水中H2O2的测定,结果满意,回收率在97.9%～101.2%之间.     

罗丹明6G缔合微粒共振散射光谱法测定过氧化氢

在0.020mol.L-1HCl-4.0×10-4mol.L-1KI-1.6×10-5mol.L-1Mo(Ⅵ)介质中,罗丹明6G(RhG)在540nm处有1个荧光峰,在540nm处有1个同步荧光峰。当有H2O2存在时,H2O2与过量的I-反应生成I3-,I3-与RhG形成缔合微粒,在320,400,595nm处产生3个共振散射(RS)峰;而在540nm处荧光峰猝灭。H2O2浓度在0.068~34μg.mL-1范围内与400nm波长处的共振散射光强度呈线性关系。据此建立了一个测定水中H2O2的共振散射光谱分析法。光谱研究结果表明,(RhG-I3)n缔合微粒和界面的形成是导致体系RS增强和荧光猝灭的根本原因。     

Scavenging of OH(*) radicals produced from H(2)O sonolysis with nitrate ions

The scavenging of OH(?) radicals formed during H(2)O sonolysis with nitrate-ions was studied in HNO(3)/NaNO(3) mixture at the constant NO(3)(-) ions concentration ([HNO(3)]+[NaNO(3)])=1 M in Ar atmosphere. Small amounts of N(2)H(5)NO(3) was added to solutions to avoid HNO(2) accumulation due to HNO(3) sonolysis. It was shown that the increase of [H(+)] causes the increase of H(2)O(2) formation rate (W(H(2)O(2)). (W(H(2)O(2)) values reach the plateau at [HNO(3)] approximately 1 M. The (W(H(2)O(2)) ratio in solution with [H(+)]=1 M and pure water was found to be equal to 2.4+/-0.4. It was assumed that (W(H(2)O(2)) increase in nitric acid medium is related to the changing of H(2)O(2) formation mechanism. In pure water H(2)O(2) is formed due to the OH(*) radicals recombination. In HNO(3)+NaNO(3) mixture the mechanism of H(2)O(2) formation consists in conversion of OH(*) radicals to NO(3)(*) radicals followed by NO(3)(*) radicals hydrolysis. Results obtained show that OH(*) radicals recombination mainly occurs in the liquid phase surrounding the cavitating bubble.     

磷酸根与磷酸基水化作用之比较—红外光谱研究

本文运用傅立叶变换红外光谱，对水／ＮａＤＥＨＰ／正庚烷反胶束体系中的磷酸根及磷酸三丁酯－水体系中磷酸基的水化作用进行了研究。     

Absolute Line Intensities for the nu6 Band of H2O2

The purpose of this work was to obtain reliable absolute intensities for the nu6 band of H2O2. It was undertaken because strong discrepancies exist between the different nu6 band intensities which are presently available in the literature (A. Perrin, A. Valentin, J.-M. Flaud, C. Camy-Peyret, L. Schriver, A. Schriver, and P. Arcas, J. Mol. Spectrosc. 1995. 171, 358), (R. May, J. Quant. Radiat. Transfer 1991. 45, 267), and (R. L. Sams, personal communication). The method which was chosen in the present work was to measure simultaneously the far-infrared absorptions and the nu6 absorptions of H2O2. Consequently, Fourier transform spectra of H2O2 were recorded at Giessen in a spectral range (370-1270 cm-1) which covers both the R branch of the torsion-rotation band and the P branch of the nu6 band which appear at low and high wavenumbers, respectively. From the low wavenumber data, the partial pressure of H2O2 present in the cell during the recording of the spectra was determined by calibrating the observed absorptions in the torsion-rotation band with intensities computed using the permanent H2O2 dipole moment measured by Stark effect (A. Perrin, J.-M. Flaud, C. Camy-Peyret, R. Schermaul, M. Winnewisser, J.-Y. Mandin, V. Dana, M. Badaoui, and J. Koput, J. Mol. Spectrosc. 1996. 176, 287-296) and [E. A. Cohen and H. M. Pickett, J. Mol. Spectrosc. 1981. 87, 582-583). In the high frequency range, this value of the partial pressure of H2O2 was used to measure absolute line intensities in the nu6 band. Finally, the line intensities in the nu6 band were fitted using the theoretical methods described in detail in our previous works. Using these new results on line intensities together with the line position parameters that we obtained previously, a new synthetic spectra of the nu6 band was generated, leading to a total band intensity of 0.185 x 10(-16) cm-1/(molecule.cm-2) at 296 K. It has to be pointed out that the new line intensities agree to within the experimental uncertainties with the individual line intensity measurements performed previously by May and by Sams. Copyright 1999 Academic Press.     

2,3-二羟基萘钼多酸有机衍生物的合成及1H NMR和IR谱学研究

本文对二种新合成的2，3－二羟基萘二钼和四钼多酸有机衍生物[n-Bu)4N]2[Mo2O5(OC10H6O)2](Ⅰ）和[n-Bu)4N]2[Mo4O10(OC10H6O)2(OCH3)2](Ⅱ)进行了红外光谱与核磁共振波谱研究，发现[Mo2O5]^2 中钼氧多桥键的红外振动频率较[Mo4O10(OCH3)2]^2 中钼氧多桥键的红外振动频率红移，而在配合物Ⅱ中2，3－二羟基中芳环的^1H化学位移较配合物Ⅰ中向低场移动。同时还发现含二钼配位中心[Mo2O5]^2 的[Mo2O5(OC10H6O)2]^2-与含四钼配位中心[Mo4O10(OCH3)2]^2 的[Mo4O10(OC10H6O)2(OCH3)2]^2-生成条件的差异仅仅只在反应体系的pH值的微小变化，说明钼多酸有机衍生物阴离子是对体系酸碱度极为敏感的物质。     

The threshold electron impact spectrum of H2O

The threshold electron spectrum of H2 O was obtained using a high resolution electron impact spectrometer combined with the penetrating field method for scattered electrons with energies close to zero eV. The valence, triplet Rydberg states, as well as the resonances were identified and are discussed in the energy region 5.2–14.3 eV. The threshold spectrum confirms the influence of resonances on the enhancement of the intensity of some Rydberg states above 10 eV. The vibrational spacing of the observed transitions of the Rydberg states indicates that the water molecule is excited in the symmetric stretching mode.     

First real-time measurement of the evolving 2H/1H ratio during water evaporation from plant leaves

We have studied the temporal behaviour of the deuterium isotope ratio of water vapour emerging from a freshly cut plant leaf placed in a dry nitrogen atmosphere. The leaf material was placed directly inside the sample gas cell of the stable isotope ratio infrared spectrometer. At the reduced pressure ( approximately 40 mbar) inside the cell, the appearance of water evaporating from the leaf is easily probed by the spectrometer, as well as the evolving isotope ratios, with a precision of about 1 per thousand. The demonstration experiment we describe measures the 2H/1H isotope ratio only, but the experiment can be easily extended to include the 18O/16O and 17O/16O isotope ratios. Plant leaf water isotope ratios provide important information towards quantification of the different components in the ecosystem water and carbon dioxide exchange.     

Counterintuitive alignment of H2(+) in intense femtosecond laser fields

The multiphoton ionization of H2 has been studied using laser pulses of 266 nm wavelength, 250 fs duration, and 5x10(13) W/cm(2) peak intensity. Dissociation of H2(+) via one-photon absorption proceeds through two channels with markedly different proton angular distributions. The lower-energy channel (2.6 eV kinetic energy release) is produced in the bond softening mechanism, which generates parallel alignment. The higher-energy channel (3.5 eV) originates from population trapping in a light-induced bound state, where bond hardening generates orthogonal, counterintuitive alignment.     

Isotope effect in hydrogen peroxide formation during H2O and D2O sonication

The kinetics of hydrogen peroxide formation have been studied during H2O and D2O sonication in the presence of argon and oxygen (f = 22 kHz, I = 3.0 W cm-2, Pac = 0.52 W ml-1, V = 20 ml, T = 20 degrees C). It was found that the sonochemical reaction rate W has a zero order with respect to hydrogen peroxide (H2O, D2O or DHO2) concentration. In argon atmosphere the kinetic isotope effect was found to be equal to alpha = WH2O/WD2O = 2.2 +/- 0.3. The alpha value decreases in H2O-D2O mixtures with increasing H2O concentration. In oxygen atmosphere the isotope effect is not observed (alpha = 1.05 +/- 0.10). It is assumed that the revealed isotope effect is related to the mechanism of water sonolysis including the H2O-Ar* and D2O-Ar* energy transition, where Ar* is an argon atom in an excited state, in nonequilibrium plasma generated by the shock-wave.     

硝酸羟胺-(H_2O)_n复合物氢键相互作用的密度泛函研究

为研究硝酸羟胺-(H_2O)_n复合物的氢键作用,采用密度泛函B3LYP方法在6-311++G(d, p)基组水平上对硝酸羟胺-(H_2O)_n复合物的结构进行优化,采用MP2/6-311++G(d, p)方法,经基组叠加误差和零点能校正计算得到复合物的相互作用能.利用自然键轨道分析方法研究复合物氢键作用的本质,并对复合物中水分子的振动光谱进行分析.计算结果表明,硝酸羟胺-(H_2O)_n复合物存在着6个硝酸羟胺-H_2O稳定构型和8个硝酸羟胺-(H_2O)_2稳定构型,且最稳定构型的相互作用能分别为52.821 kJ·mol~(-1)和73.349 kJ·mol~(-1).在硝酸羟胺-(H_2O)_n复合物中,水中H-O伸缩振动频率明显红移,且红移增大的程度与复合物稳定化能的变化趋势基本一致.     

Reactive wetting: H2O/Rh(111)

First-principles calculations imply that neither H2O bilayers nor half-dissociated, H2O+OH+H monolayers are thermodynamically stable on clean Rh(111). Thus, the experimental observation that Rh(111) supports a periodic 2D water adlayer needs an explanation. Chemistry involving common surface impurities, notably C atoms, may be the answer. Calculations show they provide favorable binding sites for H atoms detached from H2O. The resulting OH fragments can anchor a 2D water layer to the surface.     

A comparative study of the immunogold labeling on H(2)O(2)-treated and heated epoxy sections.

The purpose of this study was to compare the intensity of the immunogold labeling of H(2)O(2)-treated and heated epoxy sections. Renal swine tissue with glomerular immune complex deposits with reactivity against IgG was embedded in epoxy resin. Immunogold labeling with anti-IgG was performed on sections from these blocks. Some of these sections were treated by H(2)O(2), others were heated in a citrate solution, while some were not treated at all. Some epoxy sections, which had been exposed to both H(2)O(2) and heat, were also exposed to the same immunolabeling. The heated epoxy sections obtained an yield of specific immunogold labeling, which was twice as large as the labeling of the H(2)O(2)-treated sections. The yield of immunolabeling of the sections that had been exposed to both H(2)O(2) and heat was not significantly different from the sections that were only exposed to heat. The non-treated sections were very weakly labeled with anti-IgG. We believe that both H(2)O(2) and heat have the ability to break some chemical bonds between the epoxy resin and the antigens, but heating in citrate buffer has a larger potential in this respect than H(2)O(2). We interpret the results from the combined treatment with H(2)O(2) and heat in the following way; the bonds that are broken by H(2)O(2) will also be broken by heating in citrate solution. The practical significance of these results is that heating in citrate buffer is a more convenient method for enhancing the immunolabeling of epoxy sections than treatment with H(2)O(2).     

Off-resonance binomial preparatory pulse technique for high sensitivity MRI of H2O17

H2O17 is a freely diffusible tracer and naturally occurring isotope of O16 detectable by MRI and has been shown to be useful for assessing cerebral perfusion in animal studies using direct and indirect MR detection techniques. However, earlier MR techniques are either not sensitive to changes in small concentrations of tissue H2O17 or are not practical for use on clinical scanners. In this work, a novel method for detecting H2O17 with high sensitivity has been proposed that uses a short, intense, binomial preparatory spin lock pulse with resonance offsets for high sensitive rapid, multislice imaging of tissue H2O17. Two sets of phantom experiments were performed on the 1.5 T and repeated on 3.0 T to assess the feasibility of the proposed technique. The phantom was constructed using ovalbumin and doped with 0.4 atom% and 1.0 atom% H2O17. After obtaining initial parameters, the proposed technique was validated in an anesthetized primate model that was injected with 1.8 cc of 40 atom% H2O17. Phantom experiments showed that the proposed technique was able to detect H2O17 with relatively high sensitivity and high B1 amplitude (and small offsets) preparatory pulses produced similar results as low B1 amplitude (and larger offsets). Primate brain study showed a 42.97% difference in mean signal intensity between pre- and post-H2O17 injection. The proposed technique was successfully implemented on a clinical scanner and was able to detect H2O17 with relatively high sensitivity. Primate study has shown that such a technique can be successfully used for human imaging applications to investigate and assess cerebral perfusion.     

NSR催化剂12CaO-7Al2O3/10%K中水对NO还原性能的影响

主要讨论在不同反应温度和不同水蒸汽浓度下,新型的NOx储存-还原催化剂12CaO·7Al2O3／10％K(简称C12A7／K)中水的存在对NO还原性能的影响．研究结果表明,当存在1．2％水蒸汽,并低于500℃时,NO转化率和N2的选择性均降低,水蒸汽的存在对催化剂低温区的活性起到较明显的抑制作用;而温度高于500℃时,此抑制作用则基本消失,说明此时C12A7／K催化剂的水热稳定性较好．FT-IR结果证明储存NOx后的C12A7／K样品小形成了NO3／NO2的反应中间物种,用H2还原则可消除中间物种,以N2等形式放出。     

(H2O)n (n=1-3)和H2SO4作用下H2CO3气相分解反应机理的理论研究

本文利用CCSD(T)/6-311++(3df,3pd)//B3LYP-D3/6-311++G(3df,3pd)+ 0.9686×ZPE理论方法对(H2O)n (n=1-3)和H2SO4存在与不存在的情况下,H2CO3气相分解反应机理进行了理论研究。计算结果表明(H2O)n (n=1-3)和H2SO4都能使H2CO3气相分解反应的能垒显著地降低,其催化能力按由强到弱的顺序是H2SO4>(H2O)2>(H2O)3>H2O。     

Low energy elastic differential electron scattering from H2O

Normalized differential cross sections for elastic (rotationally averaged) electron scattering from gaseous water (H2O) are obtained using the relative flow method against helium with a thin aperture collimating source of gas instead of a tube. This method obviates the use of gas kinetic molecular diameters for helium or water. Our measurements are found to be largely in quantitative disagreement with past differential elastic electron scattering measurements and suggest that present recommended electron scattering total cross sections for water be revised.     

First real-time measurement of the evolving 2H/1H ratio during water evaporation from plant leaves

We have studied the temporal behaviour of the deuterium isotope ratio of water vapour emerging from a freshly cut plant leaf placed in a dry nitrogen atmosphere. The leaf material was placed directly inside the sample gas cell of the stable isotope ratio infrared spectrometer. At the reduced pressure (～40 mbar) inside the cell, the appearance of water evaporating from the leaf is easily probed by the spectrometer, as well as the evolving isotope ratios, with a precision of about 1 ‰. The demonstration experiment we describe measures the ²H/¹H isotope ratio only, but the experiment can be easily extended to include the ¹⁸O/¹⁶O and ¹⁷O/¹⁶O isotope ratios. Plant leaf water isotope ratios provide important information towards quantification of the different components in the ecosystem water and carbon dioxide exchange.     

甘氨酸与水分子间相互作用的理论研究

在密度泛函(DFT)B3LYP/6_311++G(3d,3p)水平,对中性甘氨酸的最小点结构Ip和H2O分子间可能存在的氢键复合物进行全自由度能量梯度优化,发现了三个氢键极小结构A、C和E,其中结构A为最稳定结构,它是H2O与甘氨酸的羧基(-COOH)形成两个氢键的结构,具有C1对称性.分别采用密度泛函理论(DFT)和MP2方法,在6-311++G(3d,3p)水平,对结构A的结构和结合能进行了比较计算,得到结合能ΔEDFT为-41.88 kJ/mol,ΔEMP2为-40.34 kJ/mol.