The assembly of small water clusters (H2O) n, n= 1− 6, on a graphite surface is studied
using a density functional tight-binding method complemented with an empirical van der
Waals force correction, with confirmation using second-order M�ller− Plesset perturbation
theory. It is shown that the optimized geometry of the water hexamer may change its original
structure to an isoenergy one when interacting with a graphite surface in some specific
orientation, while the smaller water cluster will maintain its cyclic or linear configurations (for�…

The maize endophyte Acremonium zeae is antagonistic to kernel rotting and mycotoxin
producing fungi Aspergillus flavus and Fusarium verticillioides in cultural tests for
antagonism, and interferes with A. flavus infection and aflatoxin contamination of preharvest
maize kernels. Chemical studies of an organic extract from maize kernel fermentations of
Acremonium zeae (NRRL 13540), which displayed significant antifungal activity against
Aspergillus flavus and F. verticillioides, revealed that the metabolites accounting for this�…

The heterogeneous reactions of deposited, millimeter-sized oleic acid droplets with ozone
and nitrate radicals are studied. Attenuated total reflectance infrared spectroscopy (ATR−
IR), gas chromatography− mass spectrometry (GC− MS), and liquid chromatography− mass
spectrometry (LC− MS) are used for product identification and quantification. The condensed-
phase products of the ozonolysis of oleic acid droplets are 1-nonanal (30�3% carbon yield),
9-oxononanoic acid (14�2%), nonanoic acid (7�1%), octanoic acid (1�0.2%), azelaic acid�…

The Joule heating effect on electroluminescent efficiency is important in the degradation
origin of organic light-emitting diodes (OLED). Scanning tunneling microscopy (STM) and
photoluminescence (PL) measurements were performed on the guest molecule BT (1, 4-bis
(benzothiazole-vinyl) benzene), host molecule TPBI (2, 2 ', 2 ''-(1, 3, 5-phenylene) tris-[1-
phenyl-1H-benzimidazole]), and their mixture deposited on an HOPG surface to study the
OLED degradation mechanism due to thermal heating. At room temperature, BT and TPBI in�…

Atomistic molecular dynamics simulations are used to study generation 5 polyamidoamine
(PAMAM) dendrimers immersed in a bath of water. We interpret the results in terms of three
classes of water: buried water well inside of the dendrimer surface, surface water associated
with the dendrimer− water interface, and bulk water well outside of the dendrimer. We
studied the dynamic and thermodynamic properties of the water at three pH values: high pH
with none of the primary or tertiary amines protonated, intermediate pH with only the primary�…

Supported manganese oxide catalysts were prepared by the impregnation of alumina foam
blocks washcoated with alumina and silica. The manganese content based on the weight of
the washcoats was 10 wt% calculated as MnO2. Fourier transform profiles of the Mn K-edge
EXAFS spectra for these samples gave three distinctive peaks at 0.15, 0.25, and 0.32 nm
and were close to the profiles of Mn3O4 and β-MnO2. The number of surface active sites
was determined through oxygen chemisorption measurements at a reduction temperature (T�…

The ozonolysis of mixed oleic-acid/stearic-acid (OL/SA) aerosol particles from 0/100 to 100/0
wt% composition is studied. The magnitude of the divergence of the particle beam inside an
aerosol mass spectrometer shows that, in the concentration range 100/0 to 60/40, the mixed
OL/SA particles are liquid prior to reaction. Upon ozonolysis, particles having compositions
of 75/25 and 60/40 change shape, indicating that they have solidified during reaction.
Transmission electron micrographs show that SA (s) forms needles. For particles having�…

A rapid synthesis procedure for nonagglomerated silicalite nanocrystals has been
developed. This was achieved by concentrating the precursor sol before 10− 12 h of aging
at 80� C, followed by hydrothermal synthesis at 175� C for 90 min. The high silica
concentration in the concentrated sol accelerated the aggregation of primary units that were
present early in the system. Thus, little silica nutrients were left for growth when the
secondary particles were converted to zeolite during hydrothermal reaction. As a result, fully�…