A Spectroscopic Study of the Decomposition of C2 Hydrocarbons and Methyl Amine on Pt(111) and Ru(001)

Heterogeneous catalysis plays a vital role in chemical and petroleum industries. As the catalytic reaction takes place at the interface, probing surface adsorbates becomes extremely important in order to get a better understanding about the catalytic reaction mechanism. Therefore, surface-sensitive spectroscopies appear to be the primary tool to study model catalyst systems related to different reactions. Here, we use a combination of spectroscopic techniques (RAIRS, TPD/TPRS, AES, LEED) to characterize the surface intermediates in the decomposition of C2Hx hydrocarbons and methyl amine on Pt(111) and Ru(001). This thesis focus on three different projects related to C-H, C-C, N-H and C-N activation: the characterization of C2Hx in the decomposition of vinyl iodide on Pt(111), C2Hx and CHx following the decomposition of ethylene on Ru(001), and HxCNHy in the decomposition of methyl amine on Ru(001). For each of the different systems, the surface intermediates formed from the adsorption and decomposition are characterized and a reaction mechanism is proposed, which provides new insights into the surface chemistry on Pt and Ru surfaces and facilitates the understanding and designs of new catalysts

Measurement and Shaping of Circular Airy Vortex via Cross Phase

We apply the CP to CAVs for the first time experimentally. Firstly, we introduce the propagation properties of a CAV with the LOCP in the process of measuring TCs, and measure the TCs of CAVs in the self-focusing areas experimentally. Secondly, we shape the CAVs via the HOCP and discuss the manipulaiton of singularities

One-time measurement to characterize complex amplitude single component in symmetry superposed optical vortices

Complex amplitude measurement is an essential prerequisite for light field characterization. In this work, we propose a one-time measurement method to characterize the complex amplitude of symmetry superposed optical vortices (SSOVs) with only one picture registered by CCD. This method includes two strategies we proposed. One is the ring extraction strategy for amplitude measurement, and another is the rotational measurement strategy for phase measurement. In the proof-of-concept experiment, the complex amplitude is characterized, and the mode purity is well measured. This method has excellent flexibility, rapidity, and robustness, which can be applied to various occasions and harsh conditions. Careful alignment and optimized error analysis allow us to generate and measure a single component with mode purity as high as 99.99%

Directly measuring mode purity of single component in superposed optical vortices

Mode purity is an important reference for the quality of the optical vortex. In this work, we propose a self-interference method to directly measure single component in superposed optical vortices based on phase-shifting technology. This method has excellent flexibility and robustness, which can be applied to a variety of occasions and harsh conditions. Careful alignment and optimized error analysis allow us to generate and measure single component with mode purity as high as 99.997%

Measurement and Shaping of Perfect Optical Vortex via Cross Phase

We investigate a method for the measurement and shaping of a perfect optical vortex (POV) by using the cross-phase for the first time. Experimentally, we propose a method to measure the topological charges +3 and +-5 of POVs with the low-order cross-phase (LOCP) at the Fourier plane; we realize shaping intensity distributions of POVs at the Fourier plane with the high-order cross-phase (HOCP) and show the asymmetric modulation ability of the HOCP for an optical field. Furthermore, we discuss the influence of parameters on the optical field in the shaping process. On this basis, we propose a secondary energy control method that combines the characteristics of the POV, which ensures flexible control of the shape while reducing the impact on the orbital angular momentum of the original POV. This work provides an alternative method to measure and shape a POV, which facilitates applications in optical micro-manipulation

Observation of Tunneling in the Hydrogenation of Atomic Nitrogen on the Ru(001) Surface to Form NH

The kinetics of NH and ND formation and dissociation reactions on Ru(001) were studied using time-dependent reflection absorption infrared spectroscopy (RAIRS). Our results indicate that NH and ND formation and dissociation on Ru(001) follow first-order kinetics. In our reaction temperature range (320–390 K for NH and 340–390 K for ND), the apparent activation energies for NH and ND formation were found to be 72.2 ± 1.9 and 87.1 ± 1.8 kJ/mol, respectively, while NH and ND dissociation reactions between 370 and 400 K have apparent activation barriers of 106.9 ± 4.1 and 101.8 ± 4.8 kJ/mol, respectively. The lower apparent activation energy for NH formation than that for ND as well as the comparison between experimentally measured isotope effects with theoretical results strongly indicates that tunneling already starts to play a role in this reaction at a temperature as high as 340 K

Observation of Tunneling in the Hydrogenation of Atomic Nitrogen on the Ru(001) Surface to Form NH

The kinetics of NH and ND formation and dissociation reactions on Ru(001) were studied using time-dependent reflection absorption infrared spectroscopy (RAIRS). Our results indicate that NH and ND formation and dissociation on Ru(001) follow first-order kinetics. In our reaction temperature range (320–390 K for NH and 340–390 K for ND), the apparent activation energies for NH and ND formation were found to be 72.2 ± 1.9 and 87.1 ± 1.8 kJ/mol, respectively, while NH and ND dissociation reactions between 370 and 400 K have apparent activation barriers of 106.9 ± 4.1 and 101.8 ± 4.8 kJ/mol, respectively. The lower apparent activation energy for NH formation than that for ND as well as the comparison between experimentally measured isotope effects with theoretical results strongly indicates that tunneling already starts to play a role in this reaction at a temperature as high as 340 K

Fabrication of Rattle-Type TiO₂/SiO₂ Core/Shell Particles with Both High Photoactivity and UV-Shielding Property

Rattle-type TiO2@void@SiO2 particles, with commercial TiO2 particles encapsulated into hollow SiO2 shell, were fabricated by successive coating of multilayer polyelectrolytes and SiO2 shell onto TiO2 particles and then treatment by UV irradiation to remove the polyelectrolyte layers. TEM observation showed that the composite particles had a unique rattle-type structure in which there existed void space between TiO2 core and SiO2 shell. The photocatalytic degradation of Rhodamine B indicated that these composite particles with larger void space tended to have higher photoactivity. The polyurethane films doped with rattle-type TiO2@void@SiO2 composite particles had very good UV-shielding property

Data_Sheet_1_ARF6s Identification and Function Analysis Provide Insights Into Flower Development of Punica granatum L..docx

Based on the genome and small-RNA sequencing of pomegranate, miRNA167 and three target genes PgARF6 were identified in “Taishanhong” genome. Three PgARF6 genes and their corresponding protein sequences, expression patterns in pomegranate flower development and under exogenous hormones treatments were systematically analyzed in this paper. We found that PgARF6s are nuclear proteins with conserved structures. However, PgARF6s had different protein structures and expression profiles in pomegranate flower development. At the critical stages of pomegranate ovule sterility (8.1–14.0 mm), the expression levels of PgARF6s in bisexual flowers were lower than those in functional male flowers. Interestingly, PgARF6c expression level was significantly higher than PgARF6a and PgARF6b. Under the treatment of exogenous IBA and 6-BA, PgARF6s were down-regulated, and the expression of PgARF6c was significantly inhibited. PgmiR167a and PgmiR167d had the binding site on PgARF6 genes sequences, and PgARF6a has the directly targeted regulatory relationship with PgmiR167a in pomegranate. At the critical stage of ovule development (8.1–12.0 mm), exogenous IBA and 6-BA promoted the content of GA and ZR accumulation, inhibited BR accumulation. There was a strong correlation between the expression of PgARF6a and PgARF6b. Under exogenous hormone treatment, the content of ZR, BR, GA, and ABA were negatively correlated with the expressions of PgARF6 genes. However, JA was positively correlated with PgARF6a and PgARF6c under IBA treatment. Thus, our results provide new evidence for PgARF6 genes involving in ovule sterility in pomegranate flowers.</p