Investigation of anomalons in He fragments

We have studied the mean free path of He fragments from projectile beams of Ar, Fe and Kr of energy 1 ? E ?2A GeV at different distances $\text{(L ? 2.5}\text{cm}\text{)}$ from their production point and found that they are the same, independent of their (i) energy, (ii) target size, (iii) target excitation, (iv) He multiplicities and (v) production angles.     

Diamagnetic and zeeman shifts of the ground state of arsenic donors in germanium

The technique of four-wave mixing spectroscopy has been utilized to study the magnetic field dependence of the valley-orbit splitting, 4△(B), of As donors in Ge at 1.8°K for ⊥ [111]. The upper ground level, ls(T₂), splits into two levels, one of “high” and the other of “low” diamagnetism. For donor concentration N_D ? 5 × 10¹⁵ cm^-3 we have measured the diamagnetism and g-factor for the high diamagnetism level (g ? 1.07) as a function of (< 7 T). Transitions originating from both spin-up and spin-down levels are observed, indicating that the spins are heated during the 100 n-sec laser pulse. Excellent agreement between measured and theoretical values of 4▽(B) is found (employing no adjustable parameters) if magnetic field compression of the wavefunction is taken into account.     

Structure of the products of condensation of hydroxylamine with trifluoromethyl-beta-diketones: assignments of the diastereotopic protons of the 4-methylene group in 5-hydroxy-5-trifluoromethyl-delta2-isoxazolines

The combined use of 1H NMR spectroscopy with theoretical calculations of chemical shifts (GIAO) and coupling constants (B3LYP/6-311 ++G**) of a 5-hydroxy-5-trifluoromethyl-Delta2-isoxazoline has enabled solving the problem of the assignments of the diastereotopic protons in this compound. This result has been extended to 5-hydroxy-5-trifluoromethyl-Delta2-pyrazolines and the corresponding 5-trichloromethyl derivatives.     

Magnetic and spectral studies on N-(thiophene-2-carboxamido)salicylaldimine complexes of some bivalent 3d metal ions

Metal(II) complexes of N-(thiophene-2-carboxamido)salicylaldimine (H₂TCS) of types M(H₂TCS)₂Cl₂ [M = Ni, Cu and Zn], M(HTCS)Cl [M = Co, Ni and Cu], M(HTCS)₂ [M = Mn, Fe, Co, Ni, Cu and Zn], M(TCS)·xH₂O [M = Mn, Co and Ni, x = 2; M = Cu, x = 0], Ni(TCS)py₂ and Cu(TCS)py have been prepared. Elemental analyses, molar conductance, magnetic moment, electronic, IR and ESR spectral studies have been used to characterize these complexes. The different modes of chelation of the ligand and the stereochemistry of the complexes are discussed.     

Multi-component reaction to access a library of polyfunctionally substituted 4,7-dihydropyrazolo[3,4-b]pyridines

A practical approach to polyfunctionally substituted 4,7-dihydropyrazolo[3,4-b]pyridine derivatives from heteroaryl hydrazine, 3-aryl-3-oxopropanenitriles and aldehydes have been described in the report. The present catalyst-free protocol involves the intermediacy of 5-aminopyrazole and α-cyanochalcone, which undergoes in situ Michael addition to afford title compounds in moderate to good yields. All the steps were conducted concomitantly to render the procedure as practical and straightforward as possible. The expeditious synthetic protocol experiment takes less than one hour and shows broad substrate scope.     

Triphenylphosphine and sodium iodide: a new catalyst combination to rival precious metal complexes in visible light photoredox catalysis

<正>Photoredox catalysis has changed the landscape of modern synthetic organic chemistry by prompting a dramatic increase in research activity into reactions that proceed through free radical intermediates~([1]). Instrumental in this shift in interest from two-electron to single-electron processes was the widespread appreciation of the synthetic utility of pho-     

A gamma-spectrometric method for the determination of plutonium isotope ratios

A gamma-spectrometric method using an intrinsic high resolution germanium detector has been developed for the determination of isotope ratios of plutonium from samples in solution form. The method is based on the assay of low energy gamma-rays of²³⁸Pu,²³⁹Pu,²⁴⁰Pu and²⁴¹Pu and does not require the use of branching intensities or the knowledge of detection efficiencies for different gamma rays. Since low energy gamma-rays are used, the effect of²⁴¹Am has also been studied. It is found that results are not affected up to 0.5 wt% of²⁴¹Am in plutonium samples. An accuracy of 3% is achievable in the determination of²⁴⁰Pu/²³⁹Pu and²⁴¹Pu/²³⁹Pu atom ratios as demonstrated by carrying out measurements on isotopic standards of plutonium.