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Ferromagnetic materials have a property of magnetostriction, guided wave generation is based on the magnetostrictive effect, and guided wave detection is based on the inverse magnetostrictive effect. A computation model of output signals of guided waves NDT in a ferromagnetic cylinder is proposed and discussed in this paper. It focuses on the magnetic and mechanical aspects of the system and the two linear constitutive piezomagnetic equations are used to illustrate the magnetomechanical coupling. To quantify the relationship between the input current applied to exciting coil and the output voltage induced in the receiving coil of the magnetostrictive sensor, some simplifications and assumptions are made. This model reflects a general prototype in the magnetostrictive sensor reception of guided wave in a ferromagnetic cylinder, and plays an important role in quantifying calculation and NDT in the engineering application.

This work aims to develop a method to predict the pipe defect size by modified grey system and guided wave signal recognition with matching pursuit (MP). Firstly, the evolutionary programming using mutations based on the t probability distribution (tEP) is applied to the matching pursuit method. Then, a steel pipe with a notch of different depth is tested by guided wave testing system and the measured signals are decomposed by MP with chirplet atoms and the amplitudes of defect echo are extracted. At last, the signals amplitudes are made to be the original sequence to predict the defect grow by modified grey system. The forecast error of the defect size is analyzed and the error ratio is restricted within 2%–5%. Therefore, this method can effectively estimate the defect size and the steel pipe defect can be quantitatively identified.

has been severely hampered withregardto understandingreactions on oxidesurfaces.Here, wepresent a novel method capable of investigating oxygenvacancies on surfaces of oxide single crystals as well as onpowder particles. We apply this method to demonstrate thatthe surface chemistry of formaldehyde on TiO

Thin films of HfGdO x and HfDyO x were deposited by metalorganic chemical vapor deposition (MOCVD) utilizing guanidinate precursors for Hf, Gd and Dy. The close match in the thermal properties of the precursors enabled the MOCVD of rare-earth (RE) substituted HfO 2 over a wide temperature window. Film deposition was carried out in the temperature range 300–700 °C in the presence of oxygen on Si(100) substrates. HfGdO x films were analyzed in detail for their structure, composition and morphology using X-ray diffraction, Rutherford backscattering spectrometry, proton induced X-ray emission, X-ray photoelectron spectroscopy and scanning electron microscopy. The electrical properties of HfGdO x in terms of capacitance–voltage and current–voltage characteristics of metal-insulator-semiconductor device structures were evaluated.

Evolutionary programming using mutations based on the t probability distribution (tEP) is introduced and tested by maximizing the test function. The evolutionary programming algorithm is applied to the matching pursuit method. A steel pipe with a notch is tested by guided wave testing system and the measured signal is decomposed by the matching pursuit method. The defective signal is easy to recognize from the processed signal. The defect location analyzed theoretically according to the matched result agrees well with the experiment setup. The processed signal is compared with the processed result obtained by matching pursuit based on DE, and the features are nearly the same, except that there are some difference between the wave amplitude and wave width. Therefore, matching pursuit based on tEP is a useful method to process guided wave signals and to recognize defective signals.

Guided waves have the multi-modes and dispersive characteristic and the mode conversion at boundary or with defects in pipes, which make it very difficult to identify different guided waves mode reflection signals in pipes detection. The experiment method is using guided waves to detect two stainless steel pipes, one pipe has no defect and another pipe has a hole defect. The guided waves detection echo signals are obtained. By calculating the Chirplet match atom parameters and the time frequency distributions spectrum of guided waves detection echo signals, guided waves mode with T(0,1),F(1,2) and L(0,2) are respectively identified for no defect pipe detection, and defect echo consisted by two wave-packets with T(0,1) and F(1,2) mode is also identified for defect pipe detection. The results show that the matching pursuit method has a tremendous advantage to identify different guided waves modes signals in pipes non-destructive testing.

The modified dynamic differential evolution (MDDE) algorithm is proposed and applied to matching pursuit (MP) method. Two kinds of steel pipes with blind holes, and notches of different size, respectively, are tested by guided wave test system. The measured signals are decomposed by MP and the defect signals are easy to recognize from the processed signals. The average square root of the residual signals (ASRRS) after each matching pursuit iteration are calculated. The decline trend of ASRRS becomes greater when the defects are bigger. This feature can work as a criterion to estimate the defect size of steel pipes.

Dynamic simulation in the computer is an important information technology to control safety in structural engineering. The dynamic response is very important vibration characteristic for the large crane's structure. To analysis the vibration of the crane structure and decrease the displacement of the vibration for crane's safety control, the computer information technology dynamic simulation is be introduced. The analysis results of the dynamic simulation are very precise as the experiment data acquired from the crane; furthermore, the reinforcement on the crane is successful in vibration control as the dynamic simulation predicted in the computer. So, the dynamic simulation is very important information technology in engineering safety control.

[EN] The Zn-carboxylate-based porous coordination polymer MOF-5 [Zn4O(bdc)(3)] and the metal oxide loaded materials ZnO@MOF-5 and TiO2@MOF-5 were loaded in a second step with the precursor [ClAuCO] to yield intermediate materials denoted as [ClAuCO]@MOF-5, [ClAuCO]/ZnO@MOF-5 and [ClAuCO]/TiO2@MOF-5. These composites were decomposed to Au@MOF-5, Au/ZnO@MOF-5 and Au/TiO2@MOF5 under hydrogen at 100 degrees C. The nanoparticle-loaded hybrid materials were characterised by powder X-ray diffraction (PXRD), IR spectroscopy, X-ray photoelectron spectroscopy (XPS) and N-2 sorption measurements, which reveal an intact MOF-5 structure that maintains a high specific surface area. For Au@MOF-5, crystalline Au nanoparticles were distributed over the MOF matrix in a homogeneous fashion with a size of ca. 1-3 nm, evidenced by high resolution transmission electron microscopy. In the case of Au/ZnO@MOF-5, the Au and metal oxide particles of a few nm in size were coexistent in a given volume of the MOF-5 matrix and were not separated in different crystalline MOF particles. For the TiO2 loaded materials the oxide is preferentially located near the outer surface of the MOF particles, leading to an increase of larger exterior Au particles in comparison to very small interior Au particles as observed for the other materials. Au@MOF-5, Au/ZnO@MOF-5 and Au/TiO2@MOF-5 were tested in liquid-phase oxidation of alcohols. Preliminary results show a high activity for the Au loaded materials in this reaction. This observation is attributed to the microstructure of the composites with very small Au particles distributed homogeneously over the MOF matrix., This work was supported by the Deutsche Forschungsgemeinschaft (DFG) (Research Centre "Metal Support Interaction in Heterogeneous Catalysis", SFB-558). M. M. is grateful to the Ruhr-University Research School for supporting her doctoral thesis and as well to the Evangelisches Studienwerk e. V., Villigst for a stipend. S. T. gratefully acknowledges financial support from the Fund for Scientific Research Flanders (FWO). The authors acknowledge support from the European Union (Framework 6 program under a contract from an Integrated Infrastructure Initiative, reference number 026019 ESTEEM). The authors would also like to thank M. Lieb and S. Bendix for valuable help with GC-MS analysis.

Phase-pure crystalline thin films of a mixed-valence Ru(2)(II,III) metal-organic framework with 1,3,5-benzenetricarboxylate (btc) as a linker were solvothermally grown on amorphous alumina and silica surfaces. Based on the Rietveld refinement, the structure of Ru-MOF was assigned to be analogous to [Cu(3)(btc)(2)] (HKUST-1).

A combined experimental and first principles study of Cu defects in bulk ZnO is presented. Cu particles are epitaxially deposited on the polar O-ZnOð000 1Þ surface at room temperature. Upon heating, a broadening of the quasielastic peak in high resolution electron energy loss spectra is observed, corresponding to an electronic doping effect of Cu atoms in bulk ZnO with an ionization energy of 88 meV. Cu impurities in ZnO, although commonly acting as acceptors, are presently observed to induce shallow donor states. We assign these to interstitial Cu species on the basis of a hybrid density functional study.

This study was designed to evaluate the effect of oral administration of ginseng stem-and-leaf saponin (GSLS) on immune responses in chickens vaccinated with live Newcastle disease (ND) vaccines. In experiment 1, chickens were orally administered GSLS (2.5, 5, 10, and 20mg/kg) in drinking water for 3 days, and then intranasally vaccinated with ND vaccine. Hemagglutination inhibition (HI) test showed that the optimal dose of GSLS for enhancing HI titers was 5mg/kg. In experiment 2, chickens were fed with GSLS (5mg/kg) for 7, 5 or 3 days before vaccination. Result indicated that GSLS enhanced HI titers in a time-dependent manner. The order of the duration for drinking GSLS on increasing HI titers was 7 days>5 days>3 days. In experiment 3, chickens were fed with GSLS before or after immunization. Serum was sampled at a week interval for 5 weeks for HI test, splenic lymphocytes were prepared at weeks 2 and 4 after the booster immunization for lymphocyte proliferation test (LPT) and intestinal tissues were sampled at week 4 after the booster immunization for immunohistochemistry and histological examination. Results showed that HI titer, LPT, IgA+ cells and intestinal intraepithelial lymphocytes (iIELs) were significantly higher in chickens drinking GSLS before vaccination than those after vaccination. Therefore, oral administration of GSLS in drinking water at a dose of 5mg/kg for 7 days significantly increased systemic as well as gut mucosal immunity in chickens immunized with ND vaccine. Considering the immune potentiating effect of GSLS on ND vaccine, GSLS should be evaluated for its oral adjuvant effect on the immune response against other diseases such avian influenza and infectious bursal disease.

A systematic study on the photocatalytic activity of well-defined, macroscopic bulk single-crystal ${\mathrm{TiO}}_{2}$ anatase and rutile samples has been carried out, which allows us to link photoreactions at surfaces of well-defined oxide semiconductors to an important bulk property with regard to photochemistry, the life time of $e\mathrm{\text{\ensuremath{-}}}h$ pairs generated in the bulk of the oxides by photon absorption. The anatase (101) surface shows a substantially higher activity, by an order of magnitude, for CO photo-oxidation to ${\mathrm{CO}}_{2}$ than the rutile (110) surface. This surprisingly large difference in activity tracks the bulk $e\mathrm{\text{\ensuremath{-}}}h$ pair lifetime difference for the two ${\mathrm{TiO}}_{2}$ modifications as determined by contactless transient photoconductance measurements on the corresponding bulk materials.

The adsorption of NO on single crystalline rutile TiO(2)(110) surfaces at 100 K and the subsequent formation of N(2)O via NO dimer intermediates was studied by reflection-absorption infrared spectroscopy using a UHV-FTIR system. Analysis of the IR data reveals that the occurrence of s-polarized adsorbate vibrational bands always increases the reflectivity, giving negative bands, whereas p-polarized bands are either positive or negative, depending on the reduction state of the substrate. This sign reversal of optical bands is caused by vacancy doping, which also affects the optical constants governing the complex interplay between reflection and transmission of p-polarized light on a dielectric substrate.

A Comment on the Letter by Georg H. Enevoldsen et al., Phys. Rev. Lett. 102, 136103 (2009). The authors of the Letter offer a Reply.

Metal stearate-stabilized Cu nanoparticles, synthesized by an efficient one-step process, were applied in the continuous liquid-phase synthesis of methanol. After optimizing the reduction procedure, twofold higher rates of methanol formation were found for Cu-Zn colloids, compared to the conventional ternary Cu/ZnO/Al 2 O 3 catalyst applied as fine powder in the liquid phase. Structural changes were investigated as a function of time on stream; after reduction in H 2 , spherical, well-separated 5-10 nm Cu particles stabilized by a Zn stearate shell were found. Under catalytic high-pressure conditions Zn stearate was hydrolyzed forming ZnO. High-resolution transmission electron microscopy revealed the presence of triangular ZnO prisms with truncated edges. Applying optimized synthesis conditions these triangularly shaped ZnO particles were found to be mostly attached to the spherical Cu particles. The catalytic results and the structural and spectroscopic characterization suggest that these ZnO particles act as a reservoir, releasing ZnO x species, which diffuse onto the Cu particles and promote the catalytic activity.

A newly designed ultrahigh vacuum (UHV) infrared spectroscopy apparatus dedicated to the spectroscopic characterization of oxides, singles crystals as well as powders, is described. It combines a state-of-the-art vacuum Fourier transform infrared (FTIR) spectrometer (Bruker, VERTEX 80v) with a novel UHV system (PREVAC) consisting of load-lock, distribution, measurement, and magazine chambers. The innovative design allows carrying out both reflection-absorption IR spectroscopy experiments at grazing incidence on well-defined oxide single crystal surfaces and FTIR transmission measurements for powder particles. A further unique feature of the apparatus is the entirely evacuated optical path to avoid background signals from gas phase H(2)O, CO(2), and other species, thus creating the possibility to record high-quality IR data with high sensitivity and stability, an essential prerequisite for monitoring molecular species adsorbed on oxide single-crystal surfaces. The unique performance of this new apparatus with regard to the spectroscopic characterization of adsorbates on oxide single crystals as well as on powder particles is demonstrated by case studies for two different materials, TiO(2) and ZnO.

Reduction of pancreatic β-cell mass is a key element leading to type 2 diabetes. Obesity and overweight with high levels of lipids including cholesterol are tightly linked to type 2 diabetes. The direct impact of cholesterol on pancreatic β-cells, however, has not been extensively studied. In this study, MIN6 mouse β-cell line was used to test the effect of cholesterol on pancreatic β-cell apoptosis over different doses and durations. It was found that cholesterol dose- and time-dependently induced cell death of MIN6 cells above 160 μM after 6 h treatment in vitro. Annexin-V staining revealed that cholesterol treatment significantly induced apoptosis in MIN6 cells. Cholesterol treatment resulted in the loss of the ability to retain Rhodamine 123, indicating mitochondrial damage in MIN6 cells. Cholesterol-induced cell apoptosis and mitochondrial damage were blocked by low-temperature condition. In addition, glutathione also protected MIN6 cells from cholesterol-induced cell death. It is concluded that high level of cholesterol induces cell apoptosis in MIN6 cells, which is in part due to mitochondrial dysfunction. We suggest that excessive uptake of cholesterol in β-cells may contribute to β-cell apoptosis and dysfunction and the deterioration of type 2 diabetes.

[EN] Nanoscale titania particles were synthesized inside the porous coordination polymer [Zn(4)O(bdc)(3)] (bdc = 1,4-benzene-dicarboxylate, MOF-5) by adsorption of titanium isopropoxide from the gas-phase and subsequent dry oxidation and annealing., The authors acknowledge support within the Research Centre 558 "Metal Substrate Interactions in Heterogeneous Catalysis" of the German Research Foundation (DFG). The authors wish to thank Todor Hikov for very valuable help with UV-Vis and PL measurements. M. M. is grateful to the Ruhr-University Research School [DFG GSC 98/1] for supporting her doctoral thesis and to the Evangelische Studienwerk e. V. Villigst for a stipend.

The electronic effects of H atoms at interstitial sites in ZnO have been investigated by high resolution electron energy loss spectroscopy (HREELS). A reversible doping is achieved by exposing single crystalline $(000\overline{1})$-oriented ZnO substrates to atomic hydrogen. At low temperatures, interstitial H atoms form shallow donor states. At sufficiently high temperatures, the electrons are excited into the conduction band. We use EELS to demonstrate the presence of plasmons resulting from this finite density of charge carriers in the conduction band. Above temperatures of 100 K, a strong, plasmon-induced broadening of the quasielastic peak in the HREELS data is observed. The analysis of the temperature dependence yields a donor level ionization energy of $25\ifmmode\pm\else\textpm\fi{}5\text{ }\text{ }\mathrm{meV}$.

Angelica and ChuanXiong are used to cure ischemic heart disease in China. Previous studies found that these two herbs could increase myocardial blood flow, oxygen-supply and keep myocardial oxygen balance, etc. However, the mechanisms of angiogenic effects of these two herbs are not well-known. The purpose of this study was to assess the effects of Angelica and ChuanXiong on vascular endothelial growth factor (VEGF) expression in rat myocardial infarction, on endothelial cell proliferation and quantity of vessels on chick embryo chorioallantoic membrane (CAM). In this study, rats were divided randomly into either pre-treatment or acute-treatment group and sacrificed at the end of the treatments. VEGF expression using Western blot analysis was significantly increased in the groups pre-treated with ChuanXiong and Angelica when compared to the control group ( p < 0.05). There was significant increase in VEGF expression in the rats treated acutely with Angelica ( p < 0.05). In the contrary, the rats treated with ChuanXiong showed a decrease in VEGF expression when compared to the acute-treatment control group ( p < 0.05). Similar results were observed in immunohistochemistry of VEGF expression in the myocardia. Our study also demonstrated that these two herbs significantly enhanced endothelial cell proliferation ( p < 0.05) and revascularity in CAM ( p < 0.05). The data showed that Angelica and ChuanXiong could affect VEGF expression in rat myocardial infarction, promote endothelial cell proliferation and stimulate quantity of vessels on CAM model. The results suggest that Angelica and ChuanXiong have angiogenic effects, and may provide some mechanisms for the treatment of myocardial infarction and peripheral ischemia.

No doubt a noninvasive technique for detection of focal cerebral ischemic extent, before the focus is formed, is extremely valuable. This work presents a new approach to early evaluate the degree of focal ischemic injury by combining bispectrum estimation of electroencephalograms (EEGs) with artificial neural network (ANN). The graded ischemic injuries in 24 Sprague-Dawley (SD) rats were induced for different periods of 8, 18, 30 min. Four channels of EEG were collected in each rat at the scheduled time of ischemia. The maximum bicoherence index and the weighted center of EEG bispectrum (WCOB) were extracted from the EEG bispectrum and were used as the input feature vector of a four layer (12-7-2-1) ANN for prediction. Training and testing the ANN used the 'leave one out' strategy. The levels of ischemic injury were verified and classified by observing the ischemic area in the heat shock protein (HSP70) test. The proposed system was able to correctly detect the ischemic extent in average accuracy of 91.67% of the cases. The results show that the scheme can be expected to diagnose ischemic cerebral injury in its earlier phases.

No doubt a noninvasive technique for detection of focal cerebral ischemic extent, before the focus is formed, is extremely valuable. A new approach to cerebral ischemic state analysis by approximate entropy is described in this paper. After a brief introduction to the concept, the approximate entropy, ApEn, were extracted from two different EEG time series, based on a novel cerebral ischemia experiment model of SD rat. Then the entropy values were analyzed, and the results showed that this measure of EEG complexity is sensitive to the extent of ischemic cerebral injury, ischemic and normal region can also be distinguished.

This study was designed to examine whether physiologically tolerable insulin, which maintains lower blood glucose, can protect the myocardium against ischemia/reperfusion (I/R) injury in a preclinical large animal model. Adult dogs were subjected to 50 minutes of myocardial ischemia (80% reduction in coronary blood flow) followed by 4 hours of reperfusion and treated with vehicle, glucose-insulin-potassium (GIK; glucose, 250 g/L; insulin, 60 U/L; potassium, 80 mmol/L), GK, or low-dose insulin (30 U/L) 10 minutes before reperfusion. Treatment with GIK exerted significant cardioprotective effects as evidenced by improved cardiac function, improved coronary blood flow, reduced infarct size, and myocardial apoptosis. In contrast, treatment with GK increased blood glucose level and aggravated myocardial I/R injury. It is interesting that treatment with insulin alone at the dose that reduced blood glucose to a clinically tolerable level exerted significant cardioprotective effects that were comparable to that seen in the GIK-treated group. This low-dose insulin had no effect on coronary blood flow after reperfusion but markedly reduced coronary reactive hyperemia and switched myocardial substrate uptake from fat to carbohydrate. Our results suggest that lower glucose supply to the ischemic myocardium at early reperfusion may create a "metabolic postconditioning" and thus reduce myocardial ischemia/reperfusion injury after prolonged reperfusion.

The interaction of water with the non-polar ZnO(100) surface has been studied by high resolution electron energy loss spectroscopy (HREELS) and thermal desorption spectroscopy (TDS). Adsorption of water at room temperature leads to the partial dissociation of water molecules giving rise to a well defined (2 × 1) superstructure. This observation was confirmed by the HREELS data which show the water-induced O–H stretching modes at 396 and 460 meV (3193 and 3709 cm−1) as well as the peak at 456 meV (3677 cm−1) arising from the OH species. The large red shift of the loss at 396 meV indicates unusually strong hydrogen bonding interactions of water to both neighbouring adsorbate molecules and the surface O atoms which are responsible for the partial dissociation of water molecules on the perfect ZnO(100) surface.

The interaction of hydrogen with RuO(2)(110) surfaces was studied by means of thermal desorption and vibration spectroscopies. The stoichiometric surface exposes two types of coordinatively unsaturated atoms: double-bonded O-bridge and five-fold-bonded Ru-cus, while at the O-rich surface the Ru-cus atoms are covered with single-bonded O-cus. On the stoichiometric RuO(2)(110) surface at 90 K, H(2) either adsorbs molecularly on Ru-cus sites or dissociates and forms with O-bridge an H(2)O-like surface group. If, in addition, also O-cus is present at the surface, hydrogen interacts exclusively with this species forming H(2)O-cus. This demonstrates that hydrogen reacts much more readily with O-cus than with O-bridge as expected from the reduced bond order and smaller binding energy of O-cus. It is furthermore shown that at surface temperatures below 90 K free coordinatively unsaturated Ru-cus sites are needed to activate the incoming H(2) molecules prior to any reaction with O-cus or O-bridge. Generally, Ru-cus sites play a key role for reactions of a number of molecules at the RuO(2)(110) surface. These findings are supported by recent DFT-based calculations but are at variance with other reports.

Exposure of the mixed-terminated $\mathrm{ZnO}(10\overline{1}0)$ surface to atomic hydrogen at room temperature is found to lead to drastic changes of the electrical properties. The insulator surface is found to become metallic. By employing several experimental techniques (electron energy loss spectroscopy, He-atom scattering, and scanning tunneling microscopy) together with ab initio electronic structure calculations we demonstrate that a low-temperature ($1\ifmmode\times\else\texttimes\fi{}1$) phase with two H atoms in the unit cell transforms upon heating to another ($1\ifmmode\times\else\texttimes\fi{}1$) phase with only one H atom per unit cell. The odd number of electrons added to the surface per unit cell gives rise to partially filled surface states and thus a metallization of the surface.

In the research of tissue impedance spectroscopy measurement, the authors constructed a frequency sets that produce angularly equidistant points on the Nyquist loci. The studies of simulation data model demonstrate that, by use of the same quantity of frequency points and in comparison with the frequency sets that are logarithmic and quasi-linear, the angularly equidistant frequency sets can improve the estimate accuracy of tissue electrical model parameters of alpha and fc.

The in vivo measurements of rabbit brain tissue impedance were taken under both normal and ischemic conditions by using two-electrode measurement method in the frequency range from 0.1 Hz to 1 MHz. The dynamic images about the resistivity of cerebral ischemia were reconstructed based on a 16-electrode system. The results of in vivo measurement showed that the ratio of impedance increased can be as high as 75% at frequencies lower than 10 Hz. In the range from 1 KHz to 1 MHz, the ratio showed a constant value of 15%. The electrical impedance tomography (EIT) images obtained suggested that the regions of impedance changes highly correspond to the position of ischemia. It is confirmed that the brain function changes caused by local deficiency of blood can be detected and imaged by EIT method.

We present high-resolution electron energy-loss data and theoretical modeling for the vibrational properties of an atomic monolayer of H (D) on the Pt(111) surface. Experimentally we find three loss peaks, in contrast with two peaks visible in the low-coverage case. A three-dimensional adiabatic potential-energy surface at full coverage of hydrogen is obtained through first-principles calculations. When the zero-point energy effects are included, the minimum energy adsorption site is found to be the fcc site just as in the low-coverage case. Vibrational band states for motion in this potential-energy surface are computed and the excited states associated with the observed loss peaks identified.

We present a combination of theoretical calculations and experiments for the low-lying vibrational excitations of H and D atoms adsorbed on the Pt(111) surface. The vibrational band states are calculated based on the full three-dimensional adiabatic potential energy surface obtained from first principles calculations. For coverages less than three quarters of a monolayer, the observed experimental high-resolution electron peaks at 31 and 68meV are in excellent agreement with the theoretical transitions between selected bands. Our results convincingly demonstrate the need to go beyond the local harmonic oscillator picture to understand the dynamics of this system., Comment: In press at Phys. Rev. Lett - to appear in April 2002

Adsorption and thermal dehydrogenation of NH3, adsorbed at 80 K on the open Ru(11(2) over bar 1) surface, was studied using high-resolution electron energy-loss spectroscopy (HREELS) and thermal desorption spectroscopy (TDS). For the NH3 monolayer, a strong dipole-active mode is found at 15 meV which is newly assigned to T-z, the frustrated-translation mode perpendicular to the surface of NH3 bonding with the nitrogen atom to the Ru surface. Increasing the temperature. 70% of NH3 desorbs before a channel for dehydrogenation opens at about 280 K. The remaining 30% decomposes completely during further warming to 470 K. The dehydrogenation of NH3 gives rise to four peaks in the H-2 TDS which are assigned to desorption of coadsorbed hydrogen at 220 K and three dehydrogenation reaction steps at 320, 360. and 420 K in accordance with HREELS. The reaction intermediates NH2 and NH are identified through HREELS. In a new interpretation NH2 is characterized by intense modes at 163 meV (rocking) and at 189 meV (scissoring). Using a maximum entropy algorithm six frequencies for v(Ru-N) were resolved at 46, 50, 58, 61, 69, and 75 meV.

OH species adsorbed on Pt(111) were studied in a combined investigation using scanning tunneling microscopy (STM) and high-resolution electron energy loss spectroscopy (HREELS). OH was formed by two different reactions, by reaction of H2O with O, and as an intermediate in the reaction of O with hydrogen to H2O. In both cases, two ordered OH phases were observed, a (√3×√3)R30° and a (3×3) structure, for which models are proposed. Both structures have OH coverages of 2/3, and their formation is driven by hydrogen bond formation between the adparticles; the OH adsorption site is most likely on top. OH molecules at defects in the adlayer, in particular at island edges, are spectroscopically distinguishable and contribute significantly to the vibrational spectra in disordered OH layers. This is important for the water formation reaction, where the OH islands are small. The discrepancies between previous HREELS studies on OH can be explained by the different degree of order under the various formation conditions.

The phase selective synthesis of nanocrystalline TiO2, titania, in ionic liquids (ILs) is explored. The influence not only of the IL but also of the Ti-precursor, pH, and temperature is investigated. Sonochemical synthesis, microwave synthesis and conventional heating are compared. In the case of Ti(O(i)Pr)4 (O(i)Pr = isopropyl) as the Ti-source the ILs [C4mim][Tf2N] (1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide), [C3mimOH][Tf2N] (1-(3-hydroxypropyl)-3-methylimidazolium bis(trifluoromethanesulfonyl)amide), [C4Py][Tf2N] (butylpyridinium bis(trifluoromethanesulfonyl)amide), [N1888][Tf2N] (methyltrioctylammonium bis(trifluoromethanesulfonyl)amide), and [P66614][Tf2N] (tetradecyltrihexyl phosphonium bis(trifluoromethanesulfonyl)amide) led at ambient temperature to TiO2 in the form of anatase. The morphology of nano-anatase is controlled by the IL cation. Anatase nanospheres with a crystal size below 10 nm are obtained in [C3mimOH][Tf2N], [P66614][Tf2N] and [C4Py][Tf2N], whilst nanorods with a length and diameter of ∼10 to 20 and 5 nm are formed in [N1888][Tf2N] and spindle-shaped particles with an average length of 10-25 nm are formed in [C4mim][Tf2N]. Calcination at temperatures above 730 °C leads to rutile. When using TiCl4 as the Ti-precursor an anatase-rutile mixture forms under ambient conditions. Pure rutile can be obtained under ambient conditions in the presence of an appropriate volume of aqueous HCl. At moderate to high pH values pure anatase can be obtained even from TiCl4. The photocatalytic activity of the obtained TiO2 materials has been assessed by the photodegradation of an aqueous methyl orange solution under UV light. The results indicate that the photocatalytic activity of anatase-brookite mixtures obtained in [C4mim][Tf2N], [N1888][Tf2N] and [P66614][Tf2N] is higher than that of pure anatase which is formed in [C3mimOH][Tf2N] and [C4Py][Tf2N] and competitive with commercially available catalysts.

The microporous and activated zeolitic imidazolate framework (Zn(MeIM)2; MeIM = imidazolate-2-methyl; ZIF-8) was loaded with the MOCVD precursor diethyl zinc [Zn(C2H5)2]. Exposure of ZIF-8 to the vapour of the volatile organometallic molecule resulted in the formation of the inclusion compound [Zn(C2H5)2]0.38@ZIF-8 revealing two precursor molecules per cavity. In a second step the obtained material was treated with oxygen (5 vol% in argon) at various temperatures (oxidative annealing) to achieve the composite material ZnO0.35@ZIF-8. The new material was characterized with powder XRD, FT-IR, UV-vis, solid state NMR, elemental analysis, N2 sorption measurements, and transmission electron microscopy. The data give evidence for the presence of nano-sized ZnO particles stabilized by ZIF-8 showing a blue-shift of the UV-vis absorption caused by quantum size effect (QSE). The surface structure and reactivity of embedded ZnO nanoparticles were characterized via carbon dioxide adsorption at different temperatures monitored by ultra-high vacuum FTIR techniques. It was found that the surface of ZnO nanoparticles is dominated by polar OZnO and ZnZnO facets as well as by defect sites, which all exhibit high reactivity towards CO2 activation forming various adsorbed carbonate and chemisorbed CO2δ− species.

Dye modified MOF microcrystals were characterized by fluorescence microscopy (FM) and confocal laser scanning microscopy (CLSM) which visualized the position and distribution of fluorescent dyes encapsulated into MOF crystals and provided proof for selective, post-synthetic covalent modification of the external surface of MOF crystals.

Highly active Pt–WCx/carbon nanotube (CNT) electrocatalysts for the oxygen reduction reaction (ORR) have been developed by the combination of tungsten carbide with CNTs as electrocatalyst supports. The obtained WCx/CNT and Pt–WCx/CNT samples were characterized by XRD, TEM, XPS and electrochemical measurements. The results showed that nanostructured tungsten carbide particles on carbon nanotubes could be prepared by microwave-assisted thermolytic molecular precursor method, and the particle size of tungsten carbide increased with the increase of tungsten loading. The nanostructured WCx/CNTs showed electrocatalytic activity for oxygen reduction reaction. The deposition of Pt nanoparticles on the WCx/CNTs resulted in higher electrocatalytic activity for the oxygen reduction reaction and better immunity to methanol than Pt/CNT catalysts. The unique electrocatalytic properties of the novel Pt–WCx/CNT electrocatalyst were attributed to a synergistic effect between Pt, WCx and the CNTs. The findings also indicated that WCx/CNTs were efficient electrocatalyst supports that could reduce Pt usage while the same electrocatalytic properties were kept for the ORR in direct methanol fuel cells.

The adsorption of CO on the rutile TiO(2)(110) surface was investigated using He atom scattering (HAS), high resolution electron energy loss spectroscopy (HREELS), thermal desorption spectroscopy (TDS), and different types of ab initio electronic structure calculations. The experimental and theoretical results allow to put forward a consistent picture for this rather complicated adsorbate system. At 70 K a (2x1) adlayer with a glide symmetry plane is formed, containing two molecules per unit cell which are tilted in alternate directions by about 20 degrees relative to the surface normal. For this high density phase, the theoretical calculations reveal a substantial repulsion between CO molecules on neighboring lattice sites, in accord with the results of a detailed analysis of the experimental TDS data. The CO binding energy depends strongly on coverage and varies between 0.20 eV for the saturated monolayer and 0.36 eV for isolated molecules. The CO-CO repulsion leads to the desorption of about half of the CO molecules above 70 K and the formation of low density phases. HAS gave no indication of ordered adlayers at these lower coverages. For the internal stretching vibration of the CO molecules a value of 273 meV was determined by HREELS, in very good agreement with the theoretical calculations.

A highly efficient one-step process to generate Cu-Zn colloids was developed, in which the colloidal particles were synthesized from Cu and Zn stearates by reduction with H(2) in a continuously operated stirred tank reactor. The resulting spherical, well separated particles have a size of 5-10 nm, consisting of a crystalline Cu(0) core (fcc) stabilized by a Zn stearate shell without long-range order. In situ attenuated total reflection FTIR spectroscopy was used to monitor the shift of the C-O stretching vibration of adsorbed CO as a function of temperature and pressure. The absence of the CO rotation-vibration bands of dissolved CO allowed us to obtain FTIR spectra at a CO pressure of 1.0 MPa at 473 K resulting in three shifted CO bands at 2030-2025, 1979-1978, and 1920 cm(-1). These bands indicate the presence of reduced coadsorbed Zn species on the metallic Cu surface. Cyclic CO adsorption experiments demonstrated the dynamics of the interaction between the Cu core and the Zn stearate shell.

The interaction of water with ZnO nanoparticles has been studied by means of diffuse reflectance infrared spectroscopy (DRIFTS) and ultra-high vacuum FTIR spectroscopy (UHV-FTIRS). Exposing clean ZnO powder to water at 323 K leads to both molecular and dissociative adsorption of H2O forming a number of hydroxyl species. All the OH bands are clearly identified by the adsorption of D2O showing the expected isotopic shifts. According to the vibrational and thermal stability data obtained from single crystal surfaces, the OH species observed on ZnO nanoparticles are identified as follows: (1) OH group (3620 cm(-1)) on the polar O-ZnO(0001[combining macron]) surface formed via dissociation of water on oxygen vacancy sites; (2) partial dissociation of water on the mixed-terminated ZnO(101[combining macron]0) surface yielding coexistent H2O ( approximately 3150 and 3687 cm(-1)) and OH species (3672 cm(-1)), where the molecularly adsorbed H2O is further identified by the characteristic scissoring mode at 1617 cm(-1); (3) isolated OH species (3639 and 3656 cm(-1)) formed on the mixed-terminated ZnO(101[combining macron]0) surface; (4) interaction of water with defects forming hydroxyl (or O-HO) species (3564 and 3448 cm(-1)).