Gas Phase Synthesis of the Elusive Trisilacyclopropyl Radical (SiH) via Unimolecular Decomposition of Chemically Activated Doublet Trisilapropyl Radicals (SiH).

The gas phase reaction of the simplest silicon-bearing radical silylidyne (SiH; XΠ) with disilane (SiH; XA) was investigated in a crossed molecular beams machine. Combined with electronic structure calculations, our data reveal the synthesis of the previously elusive trisilacyclopropyl radical (SiH)-the isovalent counterpart of the cyclopropyl radical (CH)-along with molecular hydrogen via indirect scattering dynamics through long-lived, acyclic trisilapropyl (i-SiH) collision complex(es). Possible hydrogen-atom roaming on the doublet surface proceeds to molecular hydrogen loss accompanied by ring closure.

The Elusive Ketene (H CCO) Channel in the Infrared Multiphoton Dissociation of Solid 1,3,5-Trinitro-1,3,5-Triazinane (RDX).

Understanding of the fundamental mechanisms involved in the decomposition of 1,3,5-trinitro-1,3,5-triazinane (RDX) still represents a major challenge for the energetic materials and physical (organic) chemistry communities mainly because multiple competing dissociation channels are likely involved and previous detection methods of the products are not isomer selective. In this study we exploited a microsecond pulsed infrared laser to decompose thin RDX films at 5 K under mild conditions to limit the fragmentation channels. The subliming decomposition products during the temperature programed desorption phase are detected using isomer selective single photoionization time-of-flight mass spectrometry (PI-ReTOF-MS).

Synthesis of Polycyclic Aromatic Hydrocarbons by Phenyl Addition-Dehydrocyclization: The Third Way.

Polycyclic aromatic hydrocarbons (PAHs) represent the link between resonance-stabilized free radicals and carbonaceous nanoparticles generated in incomplete combustion processes and in circumstellar envelopes of carbon rich asymptotic giant branch (AGB) stars. Although these PAHs resemble building blocks of complex carbonaceous nanostructures, their fundamental formation mechanisms have remained elusive. By exploring these reaction mechanisms of the phenyl radical with biphenyl/naphthalene theoretically and experimentally, we provide compelling evidence on a novel phenyl-addition/dehydrocyclization (PAC) pathway leading to prototype PAHs: triphenylene and fluoranthene.

A study on the enzymatic properties and reuse of cellulase immobilized with carbon nanotubes and sodium alginate.

Cellulase has many potential applications in ethanol production, extraction of medicinal ingredients, food, brewing, oil exploration, environmental protection. However, the widespread use of cellulase is limited by its relatively high production costs and low biological activity. Therefore, we studied the enzymatic properties and reusability of cellulase immobilized on multiwalled carbon nanotubes and sodium alginate for the first time.

A vacuum ultraviolet photoionization study on the formation of methanimine (CHNH) and ethylenediamine (NHCHCHNH) in low temperature interstellar model ices exposed to ionizing radiation.

Methylamine (CH3NH2) and methanimine (CH2NH) represent essential building blocks in the formation of amino acids in interstellar and cometary ices. In our study, by exploiting isomer selective detection of the reaction products via photoionization coupled with reflectron time of flight mass spectrometry (Re-TOF-MS), we elucidate the formation of methanimine and ethylenediamine (NH2CH2CH2NH2) in methylamine ices exposed to energetic electrons as a proxy for secondary electrons generated by energetic cosmic rays penetrating interstellar and cometary ices. Interestingly, the two products methanimine and ethylenediamine are isoelectronic to formaldehyde (H2CO) and ethylene glycol (HOCH2CH2OH), respectively.

[Effects of forest gap on seasonal dynamics of soil organic carbon and microbial biomass car- bon in Picea asperata forest in Miyaluo of Western Sichuan, Southwest China].

Effects of gap sizes (50, 100 and 150 m2) on seasonal dynamics of soil organic carbon (SOC) and microbial biomass carbon (MBC) in soil surface (0-15 cm) and subsurface (15-30 cm) were investigated in a 50-year old Picea asperata plantation in Miyaluo forest, Western Si- chuan, China. In the four seasons, the SOC and MBC contents were higher in the soil surface than in soil subsurface in the four treatments, and varied insignificantly in different seasons. Compared with the control, the SOC content increased by 35.