排序方式: 共有35条查询结果,搜索用时 15 毫秒
1.
Patrizia Ferraboschi Alberto Fiecchi Paride Grisenti Enzo Santaniello Susanna Trave 《合成通讯》2013,43(13):1569-1575
Recently, polyethylene glycols (PEGS) of various molecular weights have been proposed as solvent promoters for various reactions 1, 2. We wish to report on the use of PEG 400 as solvent for the anionic activation of potassium thioacetate, which could be used for the preparation of alkyl and benzyl thioacetates from the corresponding halides or alcohol derivatives. The method can be synthetically significant, since from thioacetates the corresponding thiols can be easily prepared under a variety of mild conditions 3. 相似文献
2.
Jahnke T Czasch A Schöffler M Schössler S Käsz M Titze J Kreidi K Grisenti RE Staudte A Jagutzki O Schmidt LP Weber T Schmidt-Böcking H Ueda K Dörner R 《Physical review letters》2007,99(15):153401
We investigate the interatomic Coulombic decay (ICD) of neon dimers following photoionization with simultaneous excitation of the ionized atom (shakeup) in a multiparticle coincidence experiment. We find that, depending on the parity of the excited state, which determines whether ICD takes place via virtual dipole photon emission or overlap of the wave functions, the decay happens at different internuclear distances, illustrating that nuclear dynamics heavily influence the electronic decay in the neon dimer. 相似文献
3.
Background
Growth hormone (GH) plays an incompletely understood role in the development of the central nervous system (CNS). In this study, we use transgenic mice expressing a growth hormone antagonist (GHA) to explore the role of GH in regulating postnatal brain, spinal cord and body growth into adulthood. The GHA transgene encodes a protein that inhibits the binding of GH to its receptor, specifically antagonizing the trophic effects of endogenous GH. 相似文献4.
Liquid 4He at pressures P(0)=0.5-30 bars and temperatures T(0)=1.5-4.2 K is discharged into vacuum through two different 2 microm nozzles. The velocities of the beam of particles obey the Bernoulli equation down to 15 m/sec. With decreasing T0 and increasing P0 the velocity and angular distributions become exceedingly narrow with Deltav/v less or similar 1% and Deltatheta less or similar 1 mrad. Optical observations indicate that the beam consists of micron-sized droplets (N greater or similar 10(9) atoms). This new droplet source provides opportunities for novel experimental studies of superfluid behavior. 相似文献
5.
Grisenti RE Schollkopf W Toennies JP Hegerfeldt GC Kohler T Stoll M 《Physical review letters》2000,85(11):2284-2287
A molecular beam consisting of small helium clusters is diffracted from a 100 nm period transmission grating. The relative dimer intensities have been measured out to the 7th order and are used to determine the reduction of the effective slit width resulting from the finite size of the dimer. From a theoretical analysis of the data which also takes into account the van der Waals interaction with the grating bars, the bond length (mean internuclear distance) and the binding energy are found to be = 52+/-4 A and |E(b)| = 1. 1+0.3/-0.2 mK. 相似文献
6.
Sanson A Rocca F Armellini C Dalba G Fornasini P Grisenti R 《Physical review letters》2008,101(15):155901
A large number of AgI-based fast-ion-conducting glasses have been investigated by K-iodine extended x-ray absorption fine structure spectroscopy (EXAFS) measurements at liquid nitrogen temperature. A general correlation between the I-Ag distance measured by EXAFS and the glass activation energy for dc ionic conductivity has been found out: glasses with longer I-Ag distances display higher ionic conductivity, independently from the chemical composition of their host glassy matrix. This behavior can be related to the progressive increase of the "pathway volume" for ionic conduction. 相似文献
7.
Purans J Afify ND Dalba G Grisenti R De Panfilis S Kuzmin A Ozhogin VI Rocca F Sanson A Tiutiunnikov SI Fornasini P 《Physical review letters》2008,100(5):055901
Extended x-ray absorption fine structure has been measured on two powdered samples of (70)Ge and (76)Ge as a function of temperature from 20 to 300 K. The effect of isotopic mass difference on the amplitude of relative atomic vibrations is neatly evidenced by the temperature dependence of the difference of Debye-Waller factors. The isotopic effect is also detected on the difference of nearest-neighbor average ineratomic distances, thanks to a resolution better than 10 fm. 相似文献
8.
KM Varier AM Vinodkumar NVSV Prasad PV Madhusudhana Rao DL Sastry Lagy T Baby MC Radhakrishna NG Puttaswamy JJ Das P Sugathan N Madhavan AK Sinha DO Kataria 《Pramana》1999,53(3):529-533
Large enhancements have been observed in the sub-barrier fusion cross sections for Ti+Ni systems in our previous studies.
Coupled channel calculations incorporating couplings to 2+ and 3− states failed to explain these enhancements completely. A possibilty of transfer channels contributing to the residual enhancements
had been suggested. In order to investigate the role of relevant transfer channels, measurements of one- and two-nucleon transfer
were carried out for 46,48Ti+61Ni systems. The present paper gives the results of these studies. 相似文献
9.
WYETH Paul 《中国科学:化学》2010,(3)
Silks represent some of the most precious ancient and historic textile artefacts in collections worldwide.Their optimum preservation demands an appreciation of their characteristics.One important concern,especially with regard to ancient Chinese silks,is whether the fabrics have been degummed.Silks with remnant sericin gum coating the fibroin fibres would require different conservation protocol.In previous research on aged silks,the presence of sericin has been inferred from amino acid analysis of hydrolysa... 相似文献
10.
T. Gassner A. Gumberidze M. Trassinelli R. Heß U. Spillmann D. Banaś K.-H. Blumenhagen F. Bosch C. Brandau W. Chen Chr. Dimopoulou E. Förster R.E. Grisenti S. Hagmann P.-M. Hillenbrand P. Indelicato P. Jagodzinski T. Kämpfer M. Lestinsky D. Liesen Yu.A. Litvinov R. Loetzsch B. Manil R. Märtin F. Nolden N. Petridis M.S. Sanjari K.S. Schulze M. Schwemlein A. Simionovici M. Steck Th. Stöhlker C.I. Szabo S. Trotsenko I. Uschmann G. Weber O. Wehrhan N. Winckler D.F.A. Winters N. Winters E. Ziegler H.F. Beyer 《X射线光谱测定》2020,49(1):204-208
We present a measurement of K-shell transitions in H-like gold (Au78+) using specially developed transmission type crystal spectrometers combined with Ge(i) microstrip detectors. The experiment has been carried out at the Experimental Storage Ring at GSI in Darmstadt. This is a first high-resolution wavelength-dispersive measurement of a K-shell transition in a high-Z H-like ion, thus representing an important milestone in this field. Ideas on possible future improvements are discussed as well. 相似文献