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K. Müller R. Henkelmann J. P. Biersack P. Mertens 《Journal of Radioanalytical and Nuclear Chemistry》1977,38(1-2):9-17
The isotopes3He,6Li,7Be and10B exhibit extremely large cross sections, between 1 and 48 kilobarn, for (n, p) or (n, α) reactions with thermal neutrons.
Together with now available extracted thermal neutron fluxes of 10( n·cm−2·sec−1 or more, these reactions present a highly sensitive method of detecting the mentioned light elements in any heavy matrix
material. Through the experimentally determined energy losses of the emitted protons or α-particles, also well resolved depth
profiles can be obtained, as demonstrated here for some relevant examples from semiconductor and fusion technology. 相似文献
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Metallcarbonyl-Synthesen,XIV. Neuartige Vanadium-, Niob- und Tantal-Komplexe mit Wasserstoff-Brücken
Wolfgang A. Herrmann Helmut Biersack Barbara Balbach Peter Wülknitz Manfred L. Ziegler 《欧洲无机化学杂志》1984,117(1):79-94
Syntheses of Metal Carbonyls, XIV. Novel Vanadium, Niobium, and Tantalum Complexes Having Hydrido Bridges The novel homo- and heterodinuclear organometallic μ-hydrido compounds 3a – c of vanadium, niobium, and tantalum have been synthesized by light-induced reactions of the hydridoniobium complex (η5-C5H5)2NbH3 ( 1 ) with the half-sandwich complexes (η5-C5H5)M(CO)4 ( 2a : M = V; 2b : M = Nb; 2c : M = Ta). These compounds have the general composition LxM – H – Nb(CO)(η5-C5H5)2. The formation of the M – H – Nb moieties is a dark-reaction preceded by two photoreactions that are independent from each other elimination of CO from 2a – c and elimination of H2 from 1 , with the extruded carbon monoxide being transfered to the (η5-C5H5)2NbH fragment; subsequent fixation of the species (η5-C5H5)2Nb(CO)H thus generated to the photogragments (η5-C5H5)M(CO)3 results in donor stabilization of these latter groups. The structural architecture of the derivatives 3a und b was established by X-Ray diffraction. The hydrogen bridges are to be considered as three-center two-electron functions that are responsible for a serious lengthening of the otherwise by at least 40 pm shorter metal-to-metal distances amounting to 371.3 pm in 3a and 373.3 pm in 3b (mean values). 相似文献
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M. Matsuoka J. F. D. Chubaci J. P. Biersack S. Watanabe N. Kuratani K. Ogata 《辐射效应与固体损伤》2013,168(1-4)
Abstract Thin Ni films were prepared at room temperature by Ni metal vapour deposition and simultaneous irradiation by Ar ions with an energy of 2–20 keV. The reaction of Ni with Si during dynamic ion-beam mixing was studied. The fluences of the ion beam were 4.7 × 1017 and 8.9 × 1017 cm?2, and arrival rate ratios Ni/Ar were 9.7 and 5.1. Concentration profiles of Ni, Si, C, and O were analysed with Auger electron spectroscopy; the surface morphology and the crystalline structure were investigated with a cross-sectional scanning electron microscope and X-ray diffractometry. The theoretical profiles were calculated with the dynamic Monte Carlo simulation T-DYN for comparison with the experimentally obtained profiles. It was possible to observe the ballistic mixing effects and also thermally activated formation of nickel silicide. 相似文献
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J. P. Biersack 《辐射效应与固体损伤》2013,168(1-2):161-162
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Sofia I. Bär Madeleine Gold Sebastian W. Schleser Dr. Tobias Rehm Alexander Bär Leonhard Köhler Lucas R. Carnell Dr. Bernhard Biersack Prof. Dr. Rainer Schobert 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(15):5003-5010
Three [1,3-diethyl-4-(p-methoxyphenyl)-5-(3,4,5-trimethoxyphenyl)imidazol-2-ylidene](L)gold(I) complexes, 4 a (L=Cl), 5 a (L=PPh3), and 6 a (L=same N-heterocyclic carbene (NHC)), and their fluorescent [4-(anthracen-9-yl)-1,3-diethyl-5-phenylimidazol-2-ylidene](L)gold(I) analogues, 4 b , 5 b , and 6 b , respectively, were studied for their localisation and effects in cancer cells. Despite their identical NHC ligands, the last three accumulated in different compartments of melanoma cells, namely, the nucleus ( 4 b ), mitochondria ( 5 b ), or lysosomes ( 6 b ). Ligand L was also more decisive for the site of accumulation than the NHC ligand because the couples 4 a / 4 b , 5 a / 5 b , and 6 a / 6 b , carrying different NHC ligands, afforded similar results in cytotoxicity tests, and tests on targets typically found at their sites of accumulation, such as DNA in nuclei, reactive oxygen species and thioredoxin reductase in mitochondria, and lysosomal membranes. Regardless of the site of accumulation, cancer cell apoptosis was eventually induced. The concept of guiding a bioactive complex fragment to a particular subcellular target by secondary ligand L could reduce unwanted side effects. 相似文献
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Selfsputtering and reflection are investigated with the Monte Carlo program TRIMSP. The results include particle and energy reflection coefficients, sputtering yields and sputtered energy versus incident angle and energy. Angular and energy distributions of reflected and sputtered particles are also given. Reflection and sputtering values are compared to show their contributions to selfsputtering. A comparison of calculated sputtering yields and sputtering efficiencies (sputtered and reflected energy) with experimental data is carried out. The systems investigated are mainly the bombardement of C, Ni, and W with self-ions at low energies. All global results are summarized in graphs, where scaling properties are utilized including the sputtering yield in a generalized form. 相似文献
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Encapsulation of Functional Organic Compounds in Nanoglass for Optically Anisotropic Coatings 下载免费PDF全文
Matthias Stöter Dr. Bernhard Biersack Dr. Sabine Rosenfeldt Markus J. Leitl Dr. Hussein Kalo Prof. Dr. Rainer Schobert Prof. Dr. Hartmut Yersin Prof. Geoffrey A. Ozin Prof. Dr. Stephan Förster Prof. Dr. Josef Breu 《Angewandte Chemie (International ed. in English)》2015,54(16):4963-4967
A novel approach is presented for the encapsulation of organic functional molecules between two sheets of 1 nm thin silicate layers, which like glass are transparent and chemically stable. An ordered heterostructure with organic interlayers strictly alternating with osmotically swelling sodium interlayers can be spontaneously delaminated into double stacks with the organic interlayers sandwiched between two silicate layers. The double stacks show high aspect ratios of >1000 (typical lateral extension 5000 nm, thickness 4.5 nm). This newly developed technique can be used to mask hydrophobic functional molecules and render them completely dispersible in water. The combination of the structural anisotropy of the silicate layers and a preferred orientation of molecules confined in the interlayer space allows polymer nanocomposite films to be cast with a well‐defined orientation of the encapsulated molecules, thus rendering the optical properties of the nanocoatings anisotropic. 相似文献
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Jochen P. Biersack 《Zeitschrift für Physik A Hadrons and Nuclei》1968,211(5):495-501
A calculation of the stopping power, range, and range straggling of low energetic atoms (E?1 MeV) is reported. The computation applied the biatomic repulsive potential of Firsov and thus had to be carried out numerically. The results, however, are presented in an analytical form. — Experimental checks were performed with recoil atoms. 96 keV Ra-224 atoms from the α-decay of Th-228 were used to measure the range distributions in several light gases. — The fast neutron induced reactions, such as (n, p)-or (n, α)-reactions, led to recoils of higher energies (up to more than 1 MeV). Their mean ranges in polycrystalline metals or amorphous oxide layers could be obtained by measuring the fraction of radioactive recoils which had left the target surface. — The experimental data are in good agreement with the theory, except at the highest energies where the observed ranges are slightly larger than predicted. 相似文献