331 research outputs found
Metabolic data
Metabolite profiling was conducted using a liquid chromatography-mass spectrometry (LC-MS) system consisting of a Waters UPLC and a Thermo Q Exactive.</p
Fundamental Studies of Nitrogen and Hydrocarbons on Metal Surfaces
The selective catalytic reduction (SCR) of NOx by hydrocarbons on noble metals is critically
important to the implementation of leaner-burning, more fuel-efficient combustion engines in
order to handle the increased amount of NOx that is produced. Understanding the reaction
mechanisms and pathways is essential for designing an effective catalytic system for exhaust
treatment. As one small part of this effort, we focus on the interaction of nitrogen atoms and
simple unsaturated hydrocarbons such as ethylene and acetylene on the Pt(111) surface under
ultra high vacuum conditions to understand the potential intermediates in NOx reduction.
In this study, we employ a variety of surface techniques, including temperature programmed
desorption (TPD), and reflection absorption infrared spectroscopy (RAIRS) in an attempt to
identify reaction pathways in hydrocarbon SCR. Three interesting observations have been made.
First, we observed the presence of π-bonded ethylene below 220 K, indicating a switch in the
preferred binding site for ethylene on N-Pt(111) as compared to the clean surface. This result
suggests that nitrogen could potentially serve as a promoter in metal catalyzed hydrogenation
reactions. Second, the formation of ammonia is observed through ND3 desorption by using
isotopically labeled ethylene or acetylene at 500 K. Because direct reaction between nitrogen
atoms and hydrogen does not proceed to form ammonia, the appearance of ammonia is believed
to be the result of a reaction between N atoms with coadsorbed ethynyl (CCH). This route to
ammonia synthesis has not been previously observed under UHV conditions. Third, above 560
K, CN coupling occurs as indicated by the desorption of HCN and the identification of CNH2 with RAIRS. In addition, a new dual UHV/“high-pressure” chamber has been constructed
and tested through two proof of principle experiments. First, nitrogen adsorption on Ni(110)
has been examined at pressures ranging up to the torr level. Second, we have studied the
hydrogenation of a nitrogen layer on Pt(111) at room temperature to determine the effects of
pressure on the ability to achieve a higher coverage of NH than what can be achieved under
UHV conditions. A detailed discussion about the system limitations are provided and possible
improvements are suggested
Additional components allow more newly developed photosynthetic systems and car engines to outperform conventional ones under specific conditions.
<p>(a) Supercharged engines outperform conventional ICEs with increasing altitude (decreasing O<sub>2</sub> concentration). (b) Likewise, “supercharged” C4 crops (corn and sorghum combined data) outperform “conventional” C3 crops (soybeans (o) and wheat (x)) with decreasing CO<sub>2</sub> concentration. (c) Hybrid cars strongly outperform their traditional counterparts under conditions of high variability in driving speed, while they perform similarly under conditions of low variability. (d) In a similar fashion, CAM plants strongly outperform their C3 counterparts in conditions of high variability in vapor pressure deficit, while they are less efficient in the absence of variability.</p
The six distinct shapes used in Experiment 4.
<p>The six distinct shapes used in Experiment 4.</p
ShenOpenPracticesDisclosure – Supplemental material for Object-Based Attention on Social Units: Visual Selection of Hands Performing a Social Interaction
<p>Supplemental material, ShenOpenPracticesDisclosure for Object-Based Attention on Social Units: Visual Selection of Hands Performing a Social Interaction by Jun Yin, Haokui Xu, Jipeng Duan and Mowei Shen in Psychological Science</p
Ultralight Three-Dimensional Boron Nitride Foam with Ultralow Permittivity and Superelasticity
Dielectrics
with ultralow permittivity within 2 times that of air,
excellent mechanical performance, and high thermal stability are highly
attractive to many applications. However, since the finding of silica
aerogels in the 1930s, no alternative ultralight porous dielectric
with density below 10 mg/cm<sup>3</sup> has been developed. Here we
present three-dimensional hierarchical boron nitride foam with permittivity
of 1.03 times that of air, density of 1.6 mg/cm<sup>3</sup>, and thermal
stability up to 1200 °C obtained by chemical vapor deposition
on a nickel foam template. This BN foam exhibits complete recovery
after cyclic compression exceeding 70% with permittivity within 1.12
times that of air. Gathering all these exceptional characters, the
BN foam should create a breakthrough development of flexible ultralow-permittivity
dielectrics and ultralight materials
Example of the mask and the results for Experiment 1b.
<p>(A) Pattern mask used in the current experiment. (B) and (C) Accuracy and reaction times (RT) for the match-mismatch task, respectively. The * and <i>ns</i> show the result of planned contrast between the three types of change and no change. * means the difference is significant, whereas <i>ns</i> means the difference is nonsignificant. (D) The ERPs recorded at FZ and FCZ. All the three types of change elicited N270 relative to no change.</p
The results for Experiment 2a.
<p>(A) and (B) The accuracy and reaction times for the four types of change, respectively. The * and <i>ns</i> show the result of planned contrast between the three types of change and no change. * means the difference is significant, whereas <i>ns</i> means the difference is nonsignificant. (C) The ERPs recorded at FZ and FCZ. Only the relevant change and both change elicited N270 relative to no change, no difference existed between irrelevant change and no change.</p
ShenSupplementalExperiments – Supplemental material for Object-Based Attention on Social Units: Visual Selection of Hands Performing a Social Interaction
<p>Supplemental material, ShenSupplementalExperiments for Object-Based Attention on Social Units: Visual Selection of Hands Performing a Social Interaction by Jun Yin, Haokui Xu, Jipeng Duan and Mowei Shen in Psychological Science</p
The results for Experiment 2b.
<p>(A) and (B) The accuracy and reaction times for the four types of change, respectively. The * and <i>ns</i> show the result of planned contrast between the three types of change and no change. * means the difference is significant, whereas <i>ns</i> means the difference is nonsignificant. (C) The ERPs recorded at FZ and FCZ. Only the relevant change and both change elicited N270 relative to no change, no difference existed between irrelevant change and no change.</p
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