scholarly journals From interstellar carbon monosulfide to methyl mercaptan: paths of least resistance

2018 ◽  
Vol 615 ◽  
pp. L2 ◽  
Author(s):  
T. Lamberts
Keyword(s):  
Reaction Network ◽  
Branching Ratios ◽  
Quantitative Information ◽  
Interstellar Cloud ◽  
Radical Reactions ◽  
Methyl Mercaptan ◽  
Intermediate Species ◽  
Reaction Energies ◽  
Carbon Monosulfide ◽  
First Time

The 29 reactions linking carbon monosulfide (CS) to methyl mercaptan (CH3SH) via ten intermediate radicals and molecules have been characterized with relevance to surface chemistry in cold interstellar ices. More intermediate species than previously considered are found likely to be present in these ices, such as trans- and cis-HCSH. Both activation and reaction energies have been calculated, along with low-temperature (T > 45 K) rate constants for the radical-neutral reactions. For barrierless radical-radical reactions on the other hand, branching ratios have been determined. The combination of these two sets of information provides, for the first time, quantitative information on the full H + CS reaction network. Early on in this network, that is, early on in the lifetime of an interstellar cloud, HCS is the main radical, while later on this becomes first CH2SH and finally CH3S.

scholarly journals Another SMEFT story: Z′ facing new results on ε′/ε, ∆MK and K → $$ \pi \nu \overline{\nu} $$

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Jason Aebischer ◽  
Andrzej J. Buras ◽  
Jacky Kumar
Keyword(s):  
Renormalization Group ◽  
Mass Difference ◽  
Branching Ratios ◽  
New Physics ◽  
Matrix Elements ◽  
Isospin Breaking ◽  
Left Handed ◽  
The Standard Model ◽  
First Time ◽  
Group Effects

Abstract Recently the RBC-UKQCD lattice QCD collaboration presented new results for the hadronic matrix elements relevant for the ratio ε′/ε in the Standard Model (SM) albeit with significant uncertainties. With the present knowledge of the Wilson coefficients and isospin breaking effects there is still a sizable room left for new physics (NP) contributions to ε′/ε which could both enhance or suppress this ratio to agree with the data. The new SM value for the K0 − $$ {\overline{K}}^0 $$ K ¯ 0 mass difference ∆MK from RBC-UKQCD is on the other hand by 2σ above the data hinting for NP required to suppress ∆MK. Simultaneously the most recent results for K+ → $$ {\pi}^{+}\nu \overline{\nu} $$ π + ν ν ¯ from NA62 and for KL → $$ {\pi}^0\nu \overline{\nu} $$ π 0 ν ν ¯ from KOTO still allow for significant NP contributions. We point out that the suppression of ∆MK by NP requires the presence of new CP-violating phases with interesting implications for K → $$ \pi \nu \overline{\nu} $$ πν ν ¯ , KS → μ+μ− and KL → π0ℓ+ℓ− decays. Considering a Z′-scenario within the SMEFT we analyze the dependence of all these observables on the size of NP still allowed by the data on ε′/ε. The hinted ∆MK anomaly together with the εK constraint implies in the presence of only left-handed (LH) or right-handed (RH) flavour-violating Z′ couplings strict correlation between K+ → $$ {\pi}^{+}\nu \overline{\nu} $$ π + ν ν ¯ and KL → $$ {\pi}^0\nu \overline{\nu} $$ π 0 ν ν ¯ branching ratios so that they are either simultaneously enhanced or suppressed relative to SM predictions. An anticorrelation can only be obtained in the presence of both LH and RH couplings. Interestingly, the NP QCD penguin scenario for ε′/ε is excluded by SMEFT renormalization group effects in εK so that NP effects in ε′/ε are governed by electroweak penguins. We also investigate for the first time whether the presence of a heavy Z′ with flavour violating couplings could generate through top Yukawa renormalization group effects FCNCs mediated by the SM Z-boson. The outcome turns out to be very interesting.

Past, Present and Future of Analytical Stems

2001 ◽  
Vol 7 (S2) ◽  
pp. 182-183
Author(s):  
C. Colliex
Keyword(s):  
Analytical Electron Microscopy ◽  
Quantitative Information ◽  
General Level ◽  
Chemical Mapping ◽  
Theoretical Understanding ◽  
Fundamental Limits ◽  
Cornell University ◽  
Resolution Imaging ◽  
First Time ◽  
Major Emphasis

Twenty five years ago, in august 1976, a specialist workshop gathered in Cornell University, at John Silcox's invitation, scientists covering a broad spectrum of interests to assess the potential of analytical electron microscopy, as to instrumentation, fundamental limits, general level of data processing and current theoretical understanding. If the STEM instrument had already been existing for a few years in Crewe's laboratory, its major emphasis, in spite of the existence of an EELS spectrometer, had focused on new modes of high resolution imaging. At the first Cornell workshop, the STEM instrument was for the first time recognized as a potentially formidable analytical instrument because of the possibility of extracting all available signals simultaneously. Furthermore it was directly suitable for digital computer processing and therefore for providing quantitative information. It was also pointed out that a major advantage of the STEM would be its potential to record EELS spectra from every point in the field of view as one scans an area to form an image, thus offering the capability of "chemical" mapping beyond "elemental" mapping.

scholarly journals Direct Synthesis of (K0.5Na0.5)NbO3Powders by Mechanochemical Method

2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
Nguyen Duc Van
Keyword(s):  
Milling Time ◽  
Direct Synthesis ◽  
Weight Ratio ◽  
Intermediate Species ◽  
X Ray Diffraction ◽  
Mechanochemical Method ◽  
X Ray ◽  
Milling Parameters ◽  
First Time ◽  
Carbonato Complex

The synthesis and structural properties of lead-free piezoelectric (K0.5Na0.5)NbO3powders prepared by mechanochemical method using Nb2O5, K2CO3, and Na2CO3as starting materials were reported. X-ray diffraction, infrared spectroscopy, Raman spectroscopy, and scanning electron microscopy were used to characterize the prepared samples. Results showed that, for the first time, by selecting the milling speed of 600 rpm and the ball-to-powder weight ratio of 35 : 1 as milling parameters, pure (K0.5Na0.5)NbO3crystalline phase was obtained directly in the as-milled samples after 5 h of milling time. The existence of a carbonato complex betweenCO32−and Nb5+ions as an intermediate species of the formation of (K0.5Na0.5)NbO3was also found.

Wet Scrubbing Removal of Methyl Mercaptan by Peroxymonosulfate under Acidic Condition

2014 ◽  
Vol 955-959 ◽  
pp. 2388-2391
Author(s):  
Shi Ying Yang ◽  
Lin Yu Feng ◽  
Mei Qing Huo ◽  
Yan Li
Keyword(s):  
Mass Transfer ◽  
Liquid Phase ◽  
Gas Phase ◽  
Gas Flow ◽  
Acidic Solution ◽  
Acidic Condition ◽  
Methyl Mercaptan ◽  
Wet Scrubbing ◽  
First Time ◽  
Rate Controlling Step

Peroxymonosulfate (PMS) was used in wet scrubbing removal of odorous gas methyl mercaptan (CH3SH) under acidic condition (pH = 2) for the first time. Even though CH3SH can hardly dissociate as CH3S− under acidic solution (pKa = 10.3), quick oxidizing reaction may occur at the gas-liquid interface by PMS alone or Co2+ activated PMS oxidation. When the gas flow is 0.5 L min-1, PMS alone can remove 94% of 60 ppm/v CH3SH. The absorption of CH3SH is the rate controlling step of the removal process, however, quick oxidizing reaction with the dissolved CH3SH(aq) molecule could improve the mass transfer of CH3SH from the gas phase into the liquid phase.

scholarly journals Phenotyping single-cell motility in microfluidic confinement

2021 ◽  
Author(s):  
Samuel A Bentley ◽  
Vasileios Anagnostidis ◽  
Hannah Laeverenz Schlogelhofer ◽  
Fabrice Gielen ◽  
Kirsty Y Wan
Keyword(s):  
Single Cell ◽  
Genetic Basis ◽  
Marine Alga ◽  
Reaction Network ◽  
Droplet Microfluidics ◽  
Model Species ◽  
Active Systems ◽  
Locomotor Behaviour ◽  
Cellular Excitability ◽  
First Time

At all scales, the movement patterns of organisms serve as dynamic read-outs of their behaviour and physiology. We devised a novel droplet microfluidics assay to encapsulate single algal microswimmers inside closed arenas, and comprehensively studied their roaming behaviour subject to a large number of environmental stimuli. We compared two model species, Chlamydomonas reinhardtii (freshwater alga, 2 cilia), and Pyramimonas octopus (marine alga, 8 cilia), and detailed their highly-stereotyped behaviours and the emergence of a trio of macroscopic swimming states (smooth-forward, quiescent, tumbling or excitable backward). Harnessing ultralong timeseries statistics, we reconstructed the species-dependent reaction network that underlies the choice of locomotor behaviour in these aneural organisms, and discovered the presence of macroscopic non-equilibrium probability fluxes in these active systems. We also revealed for the first time how microswimmer motility changes instantaneously when a chemical is added to their microhabitat, by inducing deterministic fusion between paired droplets - one containing a trapped cell, and the other, a pharmacological agent that perturbs cellular excitability. By coupling single-cell entrapment with unprecedented tracking resolution, speed and duration, our approach offers unique and potent opportunities for diagnostics, drug-screening, and for querying the genetic basis of micro-organismal behaviour.

scholarly journals Study of Λ-Hypernuclei with Stopped K− Reaction

1994 ◽  
Vol 117 ◽  
pp. 1-15
Author(s):  
Hirokazu Tamura ◽  
Ryugo S. Hayano ◽  
Haruhiko Outa ◽  
Toshimitsu Yamazaki
Keyword(s):  
Excited States ◽  
Branching Ratios ◽  
Future Prospects ◽  
Mesonic Decay ◽  
Peak Intensity ◽  
Momentum Spectra ◽  
Γ Ray ◽  
Improved Accuracy ◽  
First Time ◽  
Nuclear Targets

We summarize studies of Λ hypernuclei with stopped K− reaction carried out at KEK. The π− momentum spectra in the (stopped K−, π−) reaction were measured with light nuclear targets (4He, 7Li, 9Be, 12C and 16O). The ground and excited states of Λ4He, Λ12C and Λ16O were identified and their formation probabilities were measured. The branching ratios of π0-mesonic decay of Λ4He, Λ11B and Λ12C were measured for the first time with π0 coincidence. The lifetime of Λ4H was also determined with an improved accuracy. The π− peak intensity from Λ4H→4He+π− decay gave the Λ4H formation probabilities on these targets, where Λ4H is produced as hyperfragment except for the case of the 4He target. Concerning the formation mechanism of hyperfragments and their application to hypernuclear γ-ray spectroscopy, the running experiments and future prospects are also described.

THEORETICAL INVESTIGATION ON THE INSERTION REACTIONS OF THE GERMYLENOIDH2GeLiFWITHRH(R=Cl,SH,PH2)

2013 ◽  
Vol 12 (03) ◽  
pp. 1350003 ◽  
Author(s):  
BING-FEI YAN ◽  
WEN-ZUO LI ◽  
YU-WEI PEI ◽  
QING-ZHONG LI ◽  
JIAN-BO CHENG
Keyword(s):  
Potential Energy ◽  
Gas Phase ◽  
Potential Energy Surfaces ◽  
Stationary Points ◽  
Insertion Reaction ◽  
Insertion Reactions ◽  
Reaction Energies ◽  
Energy Surfaces ◽  
First Time ◽  
Calculated Potential Energy

The insertion reactions of the germylenoid H2GeLiF with RH (R = Cl, SH , PH2) were studied for the first time by using the DFT B3LYP and QCISD methods. The geometries of the stationary points on the potential energy surfaces of the reactions were optimized at the B3LYP/6-311+G (d,p) level of theory. The calculated results indicated that the mechanisms of the insertion reactions of H2GeLiF with HCl , H2S , and PH3are identical to each other. The QCISD/6-311++G(d,p)//B3LYP/6-311+G(d,p) calculated potential energy barriers of the three reactions are 81.80, 123.39 and 205.56 kJ/mol, and the reaction energies for the three reactions are -58.74, -33.51 and -13.35 kJ/mol, respectively. Under the same situation, the insertion reactions should occur easily in the following order H–Cl > H–SH > H–PH2. The insertion reaction in THF solution is easier than in gas phase.

NON-FRANCK–CONDON EFFECTS IN THE PHOTOIONIZATION OF N2 TO THE ${\rm N}_2^+$ A 2Πu STATE AND OF O2 TO THE ${\rm O}_2^+$ X 2Πg STATE IN THE 19–34 eV PHOTON ENERGY REGION

2002 ◽  
Vol 09 (01) ◽  
pp. 147-152
Author(s):  
J. RIUS I RIU ◽  
J. ÁLVAREZ ◽  
A. KARAWAJCZYK ◽  
M. STANKIEWICZ ◽  
P. WINIARCZYK ◽  
...  
Keyword(s):  
Cross Sections ◽  
Photoelectron Spectroscopy ◽  
Branching Ratios ◽  
Rydberg Series ◽  
Many Body ◽  
Channel Coupling ◽  
Valence States ◽  
Many Body Perturbation Theory ◽  
First Time ◽  
Franck Condon

Photoionization to the [Formula: see text] A 2Πu state and to the [Formula: see text] X 2Πg state is studied using photoelectron spectroscopy. The experimental vibrational branching ratios are obtained for the first time in the 19–34 eV region for the v′ = 0–3 levels, for both molecules. Ab initio many-body perturbation theory is used to calculate branching ratios for ionization to the [Formula: see text] A 2Πu state and branching ratios, vibrationally resolved partial cross sections and total cross section for ionization to the [Formula: see text] X 2Πg state. The Franck–Condon breakdown observed in the photoionization of the N 2 1πu electron is mainly explained by autoionization from Rydberg and valence states of N 2, whereas photoionization of the O 2πg electron is not fully explained either by channel coupling effects or by autoionization from known Rydberg series and valence states.

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