The internal structure of planetary bodies

Each planet in the Solar System is represented as a mechanically spherical cold body, possibly in rotation. It is seen that, on this basis, the properties of the planets can be understood within the already established principles of the physics of matter under high pressures. Internal structures of the planets can be deduced which are consistent with observed data, although no unique detailed structural model can be isolated at this stage.     

SULFENAMIDES AND SULFINAMIDES VI. REACTIONS OF ARYL SULFENAMIDES WITH DIPHENYLPICRYLHYDRAZYL FREE RADICAL

Abstract

Hydrogen abstraction may be postulated as the first step in reactions of aryl sulfenamides with the stable diphenylpicrylhydrazyl free radical. Differences in the reactivity of the sulfenamides are controlled by steric and electronic effects of the substituents, with attention drawn to the capacity of the divalent sulfur atom to relay these effects. Origins of decomposition products are discussed.     

THE REARRANGEMENT OF ARYLSELENENAMIDES

Abstract

Attempts to synthesize N-phenylbenzeneselenena mide always produced the isomeric p-aminodiphenyl selenide, probably as a result of an acid catalyzed rearrangement. The ease with which this rearrangement occurs is contrasted with the forcing conditions required for the analogous rearrangement of sulfenamides.     

Collision cell pressure effect on CID spectra pattern using triple quadrupole instruments: a RRKM modeling

Control of the ion internal energy in mass spectrometry is needed to establish a workable mass spectral library. The purpose of this study is to understand and to compare the pressure effects on the collision‐induced dissociation (CID) spectrum pattern recorded using triple quadrupole instruments. The monoprotonated Leucine enkephalin [YGGFL, H⁺] was used as a thermometer molecule to calibrate the electrospray ionization (ESI) and the CID internal energies deposited on the molecular species and the time scale of ion decompositions. The survival yield and the ratio of a₄/b₄ fragment ions were mainly monitored. The energy uptake for the ESI source geometry used in our study has no impact on the CID spectrum fingerprint. The collision cell pressure for the [YGGFL, H⁺] has a major influence on the SY curves slope and on the experimental time scale. To demonstrate the pressure effect on internal energy distribution, three models (threshold, thermal and collisional) based on RRKM theory were built using the Masskinetics software. As a result, the limit of each model is discussed, and the investigation demonstrates that the thermal model, using truncated Maxwell‐Boltzmann internal energy distribution, is well‐suited for simulating the experimental data at high pressure widely used in the analytical conditions. Copyright © 2013 John Wiley & Sons, Ltd.     

Homogeneous Catalytic Hydrogenation of Amides to Amines

Hydrogenation of amides in the presence of [Ru(acac)₃] (acacH=2,4‐pentanedione), triphos [1,1,1‐tris‐ (diphenylphosphinomethyl)ethane] and methanesulfonic acid (MSA) produces secondary and tertiary amines with selectivities as high as 93 % provided that there is at least one aromatic ring on N. The system is also active for the synthesis of primary amines. In an attempt to probe the role of MSA and the mechanism of the reaction, a range of methanesulfonato complexes has been prepared from [Ru(acac)₃], triphos and MSA, or from reactions of [RuX(OAc)(triphos)] (X=H or OAc) or [RuH₂(CO)(triphos)] with MSA. Crystallographically characterised complexes include: [Ru(OAc‐κ¹O)₂(H₂O)(triphos)], [Ru(OAc‐κ²O,O′)(CH₃SO₃‐κ¹O)(triphos)], [Ru(CH₃SO₃‐κ¹O)₂(H₂O)(triphos)] and [Ru₂(μ‐CH₃SO₃)₃(triphos)₂][CH₃SO₃], whereas other complexes, such as [Ru(OAc‐κ¹O)(OAc‐κ²O,O′)(triphos)], [Ru(CH₃SO₃‐κ¹O)(CH₃SO₃‐κ²O,O′)(triphos)], H[Ru(CH₃SO₃‐κ¹O)₃(triphos)], [RuH(CH₃SO₃‐κ¹O)(CO)(triphos)] and [RuH(CH₃SO₃‐κ²O,O′)(triphos)] have been characterised spectroscopically. The interactions between these various complexes and their relevance to the catalytic reactions are discussed.     

Longitudinal-transverse separations of deep-inelastic structure functions at low Q2 for hydrogen and deuterium

We report on a study of the longitudinal to transverse cross section ratio, R=sigmaL/sigmaT, at low values of x and Q2, as determined from inclusive inelastic electron-hydrogen and electron-deuterium scattering data from Jefferson Laboratory Hall C spanning the four-momentum transfer range 0.06相似文献   

High accuracy simulations of optical propagation in nanophotonic devices

We introduce a new high accuracy second-order finite-difference time-domain (FDTD) algorithm based on non-standard finite differences, and use it to investigate light propagation in subwavelength structures such as photonic crystals.     

In Situ Vesicle Formation by Native Chemical Ligation

Phospholipid vesicles are of intense fundamental and practical interest, yet methods for their de novo generation from reactive precursors are limited. A non‐enzymatic and chemoselective method to spontaneously generate phospholipid membranes from water‐soluble starting materials would be a powerful tool for generating vesicles and studying lipid membranes. Here we describe the use of native chemical ligation (NCL) to rapidly prepare phospholipids spontaneously from thioesters. While NCL is one of the most popular tools for synthesizing proteins and nucleic acids, to our knowledge this is the first example of using NCL to generate phospholipids de novo. The lipids are capable of in situ synthesis and self‐assembly into vesicles that can grow to several microns in diameter. The selectivity of the NCL reaction makes in situ membrane formation compatible with biological materials such as proteins. This work expands the application of NCL to the formation of phospholipid membranes.     

Low temperature ESR of K2Pt(CN)4Br0.3. 3.2 H2O

Electron spin resonance has been observed in high purity single crystals of K₂Pt(CN)₄Br_0.3·3.2H₂O, (KCP), in the temperature range of 4.22–80 K. Two types of paramagnetic species are found to dominate the spectrum. One of these is an inhomogeneously broadened line showing no resolved hyperfine splitting and having g_∥ = 1.946 ± 0.003 and g⊥ = 2.340 ± 0.003. The second paramagnet is identified as a Cu²⁺ impurity center with g_∥ = 2.231 ± 0.003, g⊥ = 2.079 ± 0.002 and hyperfine tensor A_∥ = 467 MHz, A_⊥ = 70 MHz.     

Six-dimensional Dirac equation

The Dirac equation in six-dimensional relativity (three space and three time) is considered and shown to correspond to particles which have spatial spin-1/2 and temporal spin-1/2. Explicit forms of the spinor transformation are found. Plane wave solutions are obtained and their properties are given in terms of spatial and temporal spins and helicities. An expression is found for the charge conjugation operator.