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Almost thirty years ago the criteria that are currently used to verify claims for the discovery of a new element were set down by the comprehensive work of a Transfermium Working Group, TWG, jointly established by IUPAC and IUPAP. The recent completion of the naming of the 118 elements in the first seven periods of the Periodic Table of the Elements was considered as an opportunity for a review of these criteria in the light of the experimental and theoretical advances in the field. In late 2016 the Unions decided to establish a new Joint Working Group, JWG, consisting of six members determined by the Unions. A first meeting of the JWG was in May 2017. One year later this report was finished. In a first part the works and conclusions of the TWG and the Joint Working Parties, JWP, deciding on the discovery of the now named elements are summarized. Possible experimental developments for production and identification of new elements beyond the presently known ones are estimated. Criteria and guidelines for establishing priority of discovery of these potential new elements are presented. Special emphasis is given to a description for the application of the criteria and the limits for their applicability.

Slowing down and stopping of the heaviest atoms, products of the fusion–evaporation nuclear reactions, during their passage through the Dubna gas-filled recoil separator has been studied using TRIM simulations. The study is important for experiments on the synthesis of super-heavy elements (SHEs) with atomic numbers around Z P = 114 produced with accelerated heavy ion (HI) beams and extracted with a separator for their detection. The average Mylar stopping power (SP) values obtained with the simulations for HIs with 82 ⩽ Z P ⩽ 92 reveal almost the same magnitudes, allowing extrapolation to the region of Z P > 92. Similar extrapolation of the ranges in an He + Ar gas mixture leads to rather small values for the heaviest atoms ( Z P ⩾ 102) as compared to the range for U. The extrapolated values have large uncertainties and should be verified with different approaches. Available SP data obtained for HIs with 18 ⩽ Z P ⩽ 92 at energies E 20 MeV/u have been analysed within various semi-empirical approaches. The analysis has shown that existing parameterizations give Mylar SP values for Z P ⩾ 82 that are very different from each other at energies of interest (around 0.1 MeV/u). We propose to use a general approach based on the HI effective charge parameterization obtained with available SP data for HIs and the hydrogen SP and effective charge corresponding to the same velocity and stopping medium as those for HIs. In this manner, the SPs of the gases H 2 , He, C 4 H 10 , and Ar as well as those of the solids Mylar, C, Al, and Ti have been obtained for any atoms with Z P ⩾ 18 (including the heaviest ones) at their reduced velocities 0 . 03 ⩽ V red ⩽ 5 . 0. The SP values derived in such a way seem to be more reliable compared to the existing semi-empirical calculations and can be used in the conditioning of experiments on the synthesis of SHEs.

Almost thirty years ago the criteria that are currently used to verify claims for the discovery of a new element were set down by the comprehensive work of a Transfermium Working Group, TWG, jointly established by IUPAC and IUPAP. The recent completion of the naming of the 118 elements in the first seven periods of the Periodic Table of the Elements was considered as an opportunity for a review of these criteria in the light of the experimental and theoretical advances in the field. In late 2016 the Unions decided to establish a new Joint Working Group, JWG, consisting of six members determined by the Unions. A first meeting of the JWG was in May 2017. One year later this report was finished. In a first part the works and conclusions of the TWG and the Joint Working Parties, JWP, deciding on the discovery of the now named elements are summarized. Possible experimental developments for production and identification of new elements beyond the presently known ones are estimated. Criteria and guidelines for establishing priority of discovery of these potential new elements are presented. Special emphasis is given to a description for the application of the criteria and the limits for their applicability.

Gas-phase chromatography studies of nihonium (Nh, $Z=113$ ) were carried out at the one-atom-at-a-time level. For the production of nihonium, the heavy-ion-induced nuclear fusion reaction of 48Ca with 243Am was used. This leads to isotopes 284,285Nh, as the direct descendants of the $\alpha$ -decaying precursors 288,289Mc. Combining the Dubna Gas-Filled Recoil Separator with gas-phase chromatographic separation, the experiment was sensitive to elemental nihonium and its adsorption behavior on Teflon, theoretically predicted by modern relativistic density functional theory. The non-observation of any decays of Nh after the chemical separation indicates a larger than expected retention of elemental Nh on a Teflon surface.

First experimental results of a chemical investigation of element 113 independently confirm the synthesis of the new elements 115 and 113 in the nuclear fusion reaction of Ca 48 + Am 243 and indicate a chemical behaviour resembling a species with a high volatility a weak interaction with inert surfaces and an enhanced reactivity towards gold surfaces.

In the Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research (FLNR JINR), construction of a new experimental complex is currently in progress (Superheavy Element Factory), aimed at the synthesis of new superheavy nuclides and the detailed study of those already synthesized. The project includes the construction of a new accelerator of stable and long-lived isotopes in the mass range A = 10–100 with an intensity of up to 10 pμ A and energy up to 8 MeV/nucleon; con-struction of a new experimental building and infrastructure for housing the accelerator with five channels for the transportation of beams to a 1200-m2 experimental hall that is equipped with systems of shielding and control for operations with radioactive materials; development of new separators of reaction products; upgrade of the existing separators and development of the new detection modules for the study of nuclear, atomic, and chemical properties of new elements. The first experiments are planned for 2018.

Discovery and investigation of the “Island of stability” of superheavy nuclei at the separator DGFRS in the 238 U- 249 Cf+ 48 Ca reactions is reviewed. The results are compared with the data obtained in chemistry experiments and at the separators SHIP, BGS, TASCA, and GARIS. The synthesis of the heaviest nuclei, their decay properties, and methods of identification are discussed and compared with the criteria that must be satisfied for claiming the discovery of a new chemical element. The role of shell effects in the stability of superheavy nuclei is demonstrated by comparison of the experimental results with empirical systematics and theoretical data.

The results on the synthesis of new superheavy elements, synthesized in complete fusion reactions of 48Ca ions with actinide targets, are summarized and analyzed. The perspectives for the synthesis of element 117, as well as of elements with Z⩾118 are also considered.

Single- and multiple-nanopore membranes are both highly interesting for biosensing and separation processes, as well as their ability to mimic biological membranes. The density of pores, their shape, and their surface chemistry are the key factors that determine membrane transport and separation capabilities. Here, we report silicon nitride (SiN) membranes with fully controlled porosity, pore geometry, and pore surface chemistry. An ultrathin freestanding SiN platform is described with conical or double-conical nanopores of diameters as small as several nanometers, prepared by the track-etching technique. This technique allows the membrane porosity to be tuned from one to billions of pores per square centimeter. We demonstrate the separation capabilities of these membranes by discrimination of dye and protein molecules based on their charge and size. This separation process is based on an electrostatic mechanism and operates in physiological electrolyte conditions. As we have also shown, the separation capabilities can be tuned by chemically modifying the pore walls. Compared with typical membranes with cylindrical pores, the conical and double-conical pores reported here allow for higher fluxes, a critical advantage in separation applications. In addition, the conical pore shape results in a shorter effective length, which gives advantages for single biomolecule detection applications such as nanopore-based DNA analysis.

The recognition criterion for discovery of a new chemical element includes two aspects, the characterization properties and the assignment properties. In this paper, we will discuss the status of element 115 experiments that have been performed in Dubna, Russia, highlighting the characterization and assignment properties as they specifically relate to a recent experiment. After discussing the status of what is known about the decay properties of element 115 [Yu.Ts. Oganessian et al. Phys. Rev. C 72 (2005) Art. No 034611], observed previously using the Dubna Gas-Filled Recoil Separator, we will discuss the prior chemical studies that have been performed on the Db descendant of element 115 [S.N. Dmitriev et al. Mendeleev Commun.(1) (2005) 1–4]. Following the success of that experiment, some additional chemical information was desired. Two separation chemistries were then developed at LLNL and JINR. LLNL utilized reversed phase chromatography and JINR utilized anion exchange chromotography to perform not only +4/+5 separations, but also intra-group separations, where Nb-like and Ta-like fractions were eluted. The results from an experiment using these chemistries for the first time during December 2005 in Dubna, Russia, will be compared with prior chemical results. We will conclude with a discussion of possible enhancements to the work already performed and the current status of the future experimental plans.

p-type silicon MOS structures were irradiated with 23 MeV electrons in vacuum for different durations. Capacitance-voltage (C/V), current-voltage (I/V) and conductance-voltage (G/V) methods were used to investigate the changes in the electrical characteristic of the MOS structures after electron irradiation. Our results show that high-energy electron irradiation generates positive charges in the oxide and at the Si-SiO 2 interface, which are frequency dependent. After electron irradiation, two kinds of interface traps are determined. The traps energy position evaluated by these three independent methods is very close to E v + 0.16 eV and B v + 0.36 eV. As these results are in a very good agreement with our earlier results, obtained by TSC and DLTS methods, the observed traps can be attributed to the boron- (V/B) and oxygen (V/O) vacancies complexes.

The influence of high-energy electron irradiation on the redistribution of silicon and oxygen atoms in implanted Si-SiO 2 structures has been investigated by Rutherford backscattering spectroscopy (RBS). Two groups of Si-SiO 2 samples implanted with different doses of silicon ions (1 × 10 12 cm -2 and 1 × 10 16 cm -2 ) are used. The ion energy of 15 keV is chosen to produce maximum radiation defects at the Si-SiO 2 interface. The structures are then irradiated with 20 MeV electrons for different durations (from 60 s up to 120 min). After electron irradiation, the redistribution of the oxygen and silicon atoms in the samples implanted with 1 × 10 12 cm -2 Si + ions is negligible: significant redistribution of these atoms is found only in Si-SiO 2 samples implanted a with dose of 10 16 cm -2 . These results demonstrate that the structural changes at the silicon surface of implanted Si-SiO 2 samples, which take place after electron irradiation, depend more strongly on the implantation dose than on the electron dose irradiation.

Impedance characteristics and voltammograms are measured for modified electrodes containing single-wall carbon nanotubes in neutral aqueous electrolyte solutions. Modifying nanotube electrodes by their exposure to a flow of heavy ions and highly active radicals is shown to substantially increase their low-frequency capacitance values and decrease the hydrogen evolution overvoltage. It was found that functional groups are not formed at nanotube surface under action of active radicals (OH and H). The phenomenon of autoelectron emission current from nanotubes to electrolyte solution at negative electrode potentials is experimentally evidenced. Keywords: Single-wall nanotubes, Impedance, Voltammetry, Autoelectron emission, Overvoltage

The recent discovery of the elements 115 and 113 in the reaction 48Ca + 243Am was confirmed by an independent radiochemical experiment based on the identification of the long-lived decay product dubnium.

The results on the synthesis of new superheavy elements, synthesized in complete fusion reactions of 48Ca ions with actinide targets, are summarized and analyzed. The perspectives for the synthesis of element 117, as well as of elements with Z⩾118 are also considered.

The changes of defect characteristics of MOS structures induced by irradiation with 23 MeV electrons are studied. The samples were irradiated for 30 or 120 s. The distributions of radiation induced interface traps, located at the Si/SiO2 interface obtained from capacitance-voltage (C-V) characteristics and decomposition of multi-frequency conductance-voltage (G-V) characteristics, are dominated by distinct defects, with different localized energy levels in the Si bandgap. The interface traps are related with Pb centers, with concentrations depending on irradiation time. The Pb1 concentration shows an order of magnitude increase as compared to the reference unirradiated sample, while Pb0 are found only after electron irradiation. The C-V characteristics indicate an increase of the positive oxide charge in SiO2 due to generation of E' defects. Defects in the Si bulk space charge region are also generated, which can be attributed to boron (V/B) and oxygen (V/O) vacancies complexes.