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In this research, the one-dimensional fluid code SIGLO-rf was used to study the internal parameters of RF capacitive discharge in carbon dioxide, focusing mainly on time-averaged and spatio-temporal distributions of discharge parameters. With the help of this code, in the range of distances between electrodes d = 0.04 – 8 cm, RF frequencies f = 3.89 – 67.8 MHz, and values of carbon dioxide pressure p = 0.1 – 9.9 Torr, averaged over the RF period axial profiles of the density of electrons, positive and negative ions were calculated as well as potential and electric field strength. It is shown that the discharge plasma in CO2 contains electrons, positive ions, as well as negative ions. The negative ions of atomic oxygen are formed by the dissociative attachment of electrons to CO2 molecules. Studies of the spatio-temporal dynamics of plasma parameters (electron density, potential and electric field strength, as well as ionization and attachment rates) in RF capacitive discharge in CO2 showed that during half of the RF period, 1 to 3 ionization bursts are usually observed. They correspond to stochastic heating in the near-electrode sheath and the formation of passive and active double layers near the sheath boundaries. The passive double layer appears in the cathode phase and maintains the discharge plasma. The active layer is formed in the anodic phase and ensures a balance of positive and negative charges escaping to the electrode during the RF period. It was found that when the conditions pd = 2 Torr cm and fd = 27.12 MHz cm are met simultaneously, during half of the RF period, 4 intense ionization peaks are observed: resulting from stochastic heating, passive, active, and additional (auxiliary) double layers. The auxiliary double layer helps bring electrons to the surface of the temporary anode and occurs near its surface inside the near-electrode sheath. Using the similarity law, the conditions for the existence of these 4 ionization peaks in a wide range of RF frequencies, carbon dioxide pressures, and distances between electrodes were verified.

In this research, the one-dimensional fluid code SIGLO-rf was used to study the internal parameters of RF capacitive discharge in carbon dioxide, focusing mainly on time-averaged and spatio-temporal distributions of discharge parameters. With the help of this code, in the range of distances between electrodes d = 0.04 – 8 cm, RF frequencies f = 3.89 – 67.8 MHz, and values of carbon dioxide pressure p = 0.1 – 9.9 Torr, averaged over the RF period axial profiles of the density of electrons, positive and negative ions were calculated as well as potential and electric field strength. It is shown that the discharge plasma in CO2 contains electrons, positive ions, as well as negative ions. The negative ions of atomic oxygen are formed by the dissociative attachment of electrons to CO2 molecules. Studies of the spatio-temporal dynamics of plasma parameters (electron density, potential and electric field strength, as well as ionization and attachment rates) in RF capacitive discharge in CO2 showed that during half of the RF period, 1 to 3 ionization bursts are usually observed. They correspond to stochastic heating in the near-electrode sheath and the formation of passive and active double layers near the sheath boundaries. The passive double layer appears in the cathode phase and maintains the discharge plasma. The active layer is formed in the anodic phase and ensures a balance of positive and negative charges escaping to the electrode during the RF period. It was found that when the conditions pd = 2 Torr cm and fd = 27.12 MHz cm are met simultaneously, during half of the RF period, 4 intense ionization peaks are observed: resulting from stochastic heating, passive, active, and additional (auxiliary) double layers. The auxiliary double layer helps bring electrons to the surface of the temporary anode and occurs near its surface inside the near-electrode sheath. Using the similarity law, the conditions for the existence of these 4 ionization peaks in a wide range of RF frequencies, carbon dioxide pressures, and distances between electrodes were verified. [ABSTRACT FROM AUTHOR]

The resonance electron capture mass spectrum of N-benzyloxycarbonyl-glycyl-L-proline shows intense negative ions in the low energy range. An ion with a record cross section of 10–16 cm2 was detected, which formed by means of sequential fragmentation of a molecular ion, initiated by the release of a benzyl radical and an H-shift in the intermediate ion and its decarboxylation. The features of electron-induced reactions in N-benzyloxycarbonyl-glycyl-L-proline suggest that its substituted derivatives will exhibit increased neuropsychotropic activity or have new properties compared to N-phenylacetyl-glycyl-L-proline derivatives. [ABSTRACT FROM AUTHOR]

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The results of a study of the analytical characteristics of a mass spectrometric method based on atmospheric pressure laser plasma-induced ionization in the negative ion detection mode. The investigation focuses on the determination of 2,4-dinitrophenol, 2,5-dinitrophenol, 2-nitro-4-chlorophenol, 2,4-dichlorophenol, 2,4-dinitrotoluene, m-dinitrobenzene, and 3,3'-dinitrobiphenyl. Depending on their chemical properties, nitroaromatic compounds are ionized to form deprotonated molecules and/or molecular ions (radical anions). Calibration dependences for these compounds were plotted, and sensitivity coefficients were determined. The research demonstrates that sensitivity depends on the nature and position of substituents in the aromatic ring. The limits of detection for nitroaromatic compounds were estimated to be within the range 1–30 pg. [ABSTRACT FROM AUTHOR]

Nowadays, organometallic complexes receive particular attention because of their use in the design of pure nanoscale metal structures. In the present work, we present results obtained from a series of studies on the degradation of metal(II) bis(acetylacetonate)s induced by low-energy electrons. These slow particles induce the formation of the acetylacetonate anion, [acac]−, and the parent anion as the most dominant species at incident electron energies near 0 eV. They also fragment the organometallic compounds via various competitive reaction channels that occur at higher energies via dissociative electron attachment. The reported data may contribute to a better understanding of the physical chemistry underlying the electron–molecule interactions, which is crucial for potential applications of these molecular systems in the deposition of nanoscale structures.

This study is the first of its kind, conducted for a city and its surroundings, in Romania. The air ionisation monitoring for Suceava Metropolitan Area (SvMA) was carried out with the PC Connectable Highly Accurate Air Ion Counter Tester COM-3200PRO II, in 34 points from SvMA (Suceava Metropolitan Area), in four time sequences of the year (January, March, July and November), in different parts of the day (morning, afternoon and evening), on active surfaces differentiated in properties (from anthropogenic to natural). The annual average value of the positive (n+) ion levels at the SvMA monitoring points was 576.6 ions/cm-3. The annual average of negative (n-) ions at the monitoring points in SvMA in 2022 was 379.5 ions/cm-3. The study shows an annual regime of n- levels which has specifically a maximum in July (598.6 ions/cm-3) and an annual regime of n+, which has a minimum in the same month (415.3 ions/cm-3). The unipolarity coefficient (k) had a value of 1.52 for the whole of SvMA for the year 2022, ranging from 5.8 in January to 0.73 in July. The lowest k values were calculated for the observation points located in the rural localities from the vicinity of the urban perimeter of Suceava and for the natural ones from the municipality.

Recent work has shown that field desorption (FD) and field ionization (FI) using activated field emitters may be performed at atmospheric pressure, too. While some limitations apply to atmospheric pressure field desorption (APFD) mass spectrometry (MS), the method can deliver both positive and negative even electron ions of highly polar or ionic compounds. Furthermore, APFD even permits the generation of positive molecular ions of polycyclic aromatic compounds. Here, an application of negative-ion APFD for the analysis of anionic surfactants contained in commercial detergent products for body care, household, and technical uses is presented. The samples include liquid soaps and shower gels, dishwashing liquids, and cooling lubricants. Surfactant solutions in methanol/water or pure methanol at 2–10 µl ml−1 were deposited on commercial 13-µm activated tungsten emitters. The emitters were positioned in front of the atmospheric pressure interface of a Fourier transform-ion cyclotron resonance (FT-ICR) mass spectrometer by means of a slightly modified nano-electrospray ionization (nanoESI) source. The entrance electrode of the interface was set to positive high voltage with respect to the emitter at ground potential. Under these conditions, negative-ion desorption was achieved. The surfactant anions, organic sulfates and organic sulfonates, were characterized by accurate mass-based formula assignments, and in part, by tandem mass spectrometry. The negative-ion APFD spectra were compared to results by negative-ion electrospray ionization (ESI) either obtained using the FT-ICR mass spectrometer or by using a trapped ion mobility-quadrupole-time-of-flight (TIMS-Q-TOF) instrument when product ions of low m/z needed to be detected in tandem MS. [ABSTRACT FROM AUTHOR]

Optimization of negative ion sources operated with deuterium may be limited by the lack of data on fundamental processes. Insight can be obtained from studies focusing on a direct comparison of H 2 and D 2 plasmas. Herein, the ECR volume negative ion source 'Prometheus I' operates with both H 2 and D 2 gases and the properties of the generated plasmas are probed by means of electrostatic probe and laser induced photo-detachment. A parametric study, involving pressure and microwave (2.45 GHz) power variation, reveals similar qualitative trends for most of the plasma properties in both gases. However, quantitively, differences do exist for the plasma potential, the electron density and temperature, and the negative ion to electron density ratio. Electron energy distribution functions are thus isotope dependent. Overall, nearly the same maximal H − and D − negative ion densities are achieved (i.e. 4 × 1 0 9 c m − 3 ). The results are eventually elucidated with respect to the ECR heating mechanism, and the production and destruction paths of the negative ions. [ABSTRACT FROM AUTHOR]

A study is performed of electron-induced reactions with uracil, thymine, 5-hydroxymethyluracil, cytosine, 5-methylcytosine, and 5-hydroxymethylcytosine. The processes responsible for the formation of negative ions in the studied objects are identified. Features of the formation of the mass spectra of hydroxymethyl derivatives are associated with the abstraction and destruction of substituents. The cross sections of [M–H]− ions are determined in the <3 eV range of energies: (1.1–2.6) × 10−18 cm2 for uracils and (3.6–5.0) × 10−19 cm2 for cytosines. [ABSTRACT FROM AUTHOR]

Acenaphtho[1,2-k]fluoranthene (1) is synthesized via tandem cyclization during the dehydrofluorination of 1,4-di(1-naphthyl)-2,5-difluorobenzene (2) on activated γ-Al2O3. Presence of residual hydroxyl groups in alumina reduce the yield of target product 1 because of the side hydrolysis of fluoroarenes with the formation a product of partial cyclization, 9-(1-naphthyl)fluoranthen-8-ol (1b). The formation of negative ions (NI) of compounds 1 and 2 in the gas phase is studied by means of dissociative electron attachment (DEA) spectroscopy. Long-lived molecular NIs 1 and 2 are registered at the thermal energies of electrons, and patterns of their fragmentation are established. The adiabatic electron affinities of compounds 1 and 2 are estimated in the Arrhenius approximation and equal 1.17 ± 0.12 and 0.71 ± 0.07 eV, respectively, which agree with data from quantum chemical modeling at the level of the density functional theory (DFT). Electronic transitions for compounds 1 and 2 are studied via optical absorption and fluorescence spectroscopy. Fluorescence quantum yields are measured, and the resulting data are interpreted according to the time dependent DFT. The electrochemical properties of compounds 1, 1b, and 2 are studied via cyclic voltamperometry, and the levels of boundary molecular orbitals are estimated on the basis of their formal potentials of reduction and oxidation. [ABSTRACT FROM AUTHOR]

Negative ion mass spectrometry is used to study processes of resonant electron attachment by 5‑methyluridine and 3'-deoxythymidine nucleoside molecules in the electron 0–14 eV range of energies. It is established that they are similar to those in nucleosides studied earlier (uridine, deoxyuridine, thymidine). The main channels of the fragmentation of molecular ions are revealed, and the absolute cross sections for the formation of fragment ions are determined. It is found that the intensity of the breaking the glycosidic bond in 3'-deoxythymidine in the region of low energies is two and a half orders of magnitude below the one in stavudine, testifying to the prospect of replacing the antiretroviral drug stavudine with 3'-deoxythymidine if radiation therapy is required for oncological diseases contracted as complications of HIV. [ABSTRACT FROM AUTHOR]

Infectious diseases (e.g., coronavirus disease 2019) dramatically impact human life, economy and social development. Exploring the low-cost and energy-saving approaches is essential in removing infectious virus particles from indoors, such as in classrooms. The application of air purification devices, such as negative ion generators (ionizers), gains popularity because of the favorable removal capacity for particles and the low operation cost. However, small and portable ionizers have potential disadvantages in the removal efficiency owing to the limited horizontal diffusion of negative ions. This study aims to investigate the layout strategy (number and location) of ionizers based on the energy-efficient natural ventilation in the classroom to improve removal efficiency (negative ions to particles) and decrease infection risk. Three infected students were considered in the classroom. The simulations of negative ion and particle concentrations were performed and validated by the experiment. Results showed that as the number of ionizers was 4 and 5, the removal performance was largely improved by combining ionizer with natural ventilation. Compared with the scenario without an ionizer, the scenario with 5 ionizers largely increased the average removal efficiency from around 20% to 85% and decreased the average infection risk by 23%. The setup with 5 ionizers placed upstream of the classroom was determined as the optimal layout strategy, particularly when the location and number of the infected students were unknown. This work can provide a guideline for applying ionizers to public buildings when natural ventilation is used. [ABSTRACT FROM AUTHOR]

In this study, we have measured the negative ion mobility in O2 at high pressures with a little amount of H2O concentration between 15 and 17,000 ppb. After that, we carried out a Monte Carlo simulation using mobility of electrons, that of the ions obtained in the measurements, and rate coefficients of ion‐molecule reactions. As a result, the mobility value 2.39 cm2/V·s of O4¯ is obtained in ultrahigh purity O2 of which the H2O concentration is between 15 and 100 ppb. Moreover, the mobility decreases with the H2O concentrations at which the ion species are considered to be O2¯·(H2O)n (n = 1, 2, 3). Then, we compared the experimental result with that of the simulation and estimated the ion mobility and rate coefficients of ion molecule reactions. Simulation results using estimated values of the ion mobility and rate coefficients agree well with measurement results. [ABSTRACT FROM AUTHOR]

We report novel data on ion-pair formation in hyperthermal (30-800 eV) neutral potassium collisions with neutral pyrimidine (Pyr, C4H4N2) molecules. In this collision regime, negative ions formed by electron transfer from the alkali atom to the target molecule were time-of-flight mass analyzed and the fragmentation patterns and branching ratios have been obtained. The most abundant product anions have been assigned to CN- and C2H- and the electron transfer mechanisms are comprehensively discussed. Particular importance is also given to the efficient loss of integrity of the pyrimidine ring in the presence of an extra electron, which is in contrast to dissociative electron attachment experiments yielding the dehydrogenated parent anion. Theoretical calculations were performed for pyrimidine in the presence of a potassium atom and provided a strong basis for the assignment of the lowest unoccupied molecular orbitals accessed in the collision process. In order to further our knowledge about the collision dynamics, potassium cation (K+) energy loss spectrum has been obtained and within this context, we also discuss the role of the accessible electronic states. A vertical electron affinity of (-5.69 ± 0.20) eV was obtained and may be assigned to a π 3 * (b 1) state that leads to CN- formation.

TRANSPORT PROBLEMS 2022 Volume 17 Issue 2 PROBLEMY TRANSPORTU DOI: 10.20858/tp.2022.17.2.02 Keywords: negative ions; car ionizer; mathematical modeling; comfort of car passengers Mykola BILIAIEV1 , Oleksandr PSHINKO2 , Tetiana RUSAKOVA 3 *, Viktoriia BILIAIEVA4 , Aleksander SŁADKOWSKI5 MATHEMATICAL MODELING OF THE AEROION MODE IN A CAR Summary. In this study, a mathematical method is proposed for calculating the concentration field of air ions of different polarities and dust levels in the passenger compartment, taking into account the geometry of the passenger compartment and seats, shelves, and other internal elements of the passenger compartment. The method also takes into account changes in the rate of the air flow ventilation, the location and number of ionizers, and sources of positive ions and dust, taking into account their different intensities and locations. On the basis of a numerical model for this method, software has been developed that allows users to carry out computational experiments without requiring much time for calculation. Based on the results, the optimal location of the ionizer in the passenger compartment of the car was determined to ensure comfortable conditions for the stay of passengers, which favorably affects their health. It has been found that the presence of two ionizers is optimal for creating comfort in the car with an ionization intensity of Qn = 0,47 × (10)^10 ions/s located at the top of the car. If there is one ionizer located on the dashboard or at the top of the car with a higher ionization rate than Qn = 0,21 × (10)^11 ions/s, it is not possible to simultaneously provide optimal ionization parameters for passengers in the front and rear seats of the car.

Intense signals of [M–H]– ions have been detected in the low-energy region of the resonance electron capture mass spectra of xanthine and its methyl derivatives. It was assumed that xanthine molecules can act as radioprotectors in living cells. It was concluded that the discovered release of the carbonyl and methyl groups is associated with xanthine metabolism reactions in the tissues of living organisms. [ABSTRACT FROM AUTHOR]

An experimental study of 0.5-5.0 keV-energy H+ ion scattering on Cu(100) has been presented at a grazing scattering angle of 7°. The velocity dependent ion fractions have been measured in this work. The positive-ion fraction increases with the increase of incident velocity, which can be described by the exponential scaling. In particular, the threshold velocity for the positive-ion fraction is observed at about 0.25 a.u., and explained by the Auger ionization process. The negative-ion fraction increases monotonically with the impact velocity, which can be explained by the first type of the parallel velocity effect. Considering the formation of positive ions and the contribution of the parallel velocity effect, the negative-ion fraction is calculated by the modified theoretical model and the general trend is consistent with the experimental data. [ABSTRACT FROM AUTHOR]

This study is the first of its kind, conducted for a city and its surroundings, in Romania. The air ionisation monitoring for Suceava Metropolitan Area (SvMA) was carried out with the PC Connectable Highly Accurate Air Ion Counter Tester COM-3200PRO II, in 34 points from SvMA (Suceava Metropolitan Area), in four time sequences of the year (January, March, July and November), in different parts of the day (morning, afternoon and evening), on active surfaces differentiated in properties (from anthropogenic to natural). The annual average value of the positive (n+) ion levels at the SvMA monitoring points was 576.6 ions/cm-3. The annual average of negative (n-) ions at the monitoring points in SvMA in 2022 was 379.5 ions/cm-3. The study shows an annual regime of n-levels which has specifically a maximum in July (598.6 ions/cm-3) and an annual regime of n+, which has a minimum in the same month (415.3 ions/cm-3). The unipolarity coefficient (k) had a value of 1.52 for the whole of SvMA for the year 2022, ranging from 5.8 in January to 0.73 in July. The lowest k values were calculated for the observation points located in the rural localities from the vicinity of the urban perimeter of Suceava and for the natural ones from the municipality. [ABSTRACT FROM AUTHOR]

We propose a low-density discharge plasma model that takes into account the impact of oxygen admixture in typical conditions of complex (dusty) plasmas. Numerical simulations based on this model show that the concentration of negative ions turns out to be very high, and they play an important role in the overall kinetics in this particular range of plasma conditions. The ambipolar diffusion electric field drags these negative ions into the center of the plasma. The density of negative ions is high enough to push the negatively charged dust component out of the center, both by weakening the radial electric field and by increasing the thermophoretic force. This phenomenon was observed in the published experiment and qualitatively supports the proposed model. Additionally, the proposed model allows an alternative explanation of the experiment. [ABSTRACT FROM AUTHOR]

The Karlsruhe Tritium Neutrino (KATRIN) experiment is a large-scale effort to probe the absolute neutrino mass scale with a sensitivity of 0.2 eV (90% confidence level), via a precise measurement of the endpoint spectrum of tritium β-decay. This work documents several KATRIN commissioning milestones: the complete assembly of the experimental beamline, the successful transmission of electrons from three sources through the beamline to the primary detector, and tests of ion transport and retention. In the First Light commissioning campaign of autumn 2016, photoelectrons were generated at the rear wall and ions were created by a dedicated ion source attached to the rear section; in July 2017, gaseous 83mKr was injected into the KATRIN source section, and a condensed 83mKr source was deployed in the transport section. In this paper we describe the technical details of the apparatus and the configuration for each measurement, and give first results on source and system performance. We have successfully achieved transmission from all four sources, established system stability, and characterized many aspects of the apparatus.

The resonant electron capture negative ion mass spectrum of 1H-1,2,4-triazole has been obtained. The peaks of effective yield curves for negative ions in the electron energy range of 5–12 eV correlate with the energies of singlet transitions in the 1H-1,2,4-triazole molecule. Based on this correlation, the observed resonance states of negative molecular ions are attributed to intershell resonances. [ABSTRACT FROM AUTHOR]

In this review, we present the recent discovery and confirmation of a new negative molecular ion, the CH 4 − anion. The experimental identification of this high-spin exciplex was difficult because it overlaps with the negative oxygen ion commonly present as a contaminant in vacuum systems and with the same mass-spectrometric signature. Born–Oppenheimer molecular dynamics (BOMD) simulations finally reveal that this anion is a quartet (S = 3 / 2) metastable species, which leads to the formation of a molecular ( CH 2 : H 2 ) − excited complex. [ABSTRACT FROM AUTHOR]

The presence of negative air ions (NAI) is suggested to be a beneficial factor in improving psychological status and used in treating depression as an alternative approach. However, more biological evidence from animal models is needed to ensure the effects of NAI on the mood regulation, through which can facilitate identification of possible underlying mechanisms. In this study, the chronic mild stress (CMS) protocol was used to induce depressive-like behaviors in mice, and the effects of NAI exposure on CMS-induced depression-like behaviors were examined. Thirty-day NAI exposure prevented the CMS-induced depression-like behaviors as shown by the restoration of sucrose preference and reduced immobility time in the tail suspension test. In addition, the elevation of serous corticosterone was present in CMS-treated mice but not existed in those with the NAI exposure. Furthermore, we observed altered ratios of some cytokines secreted by type 1 T helper (Th1) cells and Th2 cells in CMS-treated mice, but it could be restored after NAI exposure. In conclusion, NAI intervention is able to ameliorate CMS-induced depression-like behaviors in mice, and this effect is associated with the alteration of corticosterone and functional rebalance between Th1 and Th2 cells. [ABSTRACT FROM AUTHOR]

Long-term exposure to surgical smoke generated from electrocautery can increase health risks for medical personnel. Surgical smoke contains high concentrations of nanoparticles (NP, diameter ≤200 nm) and particulate matters with diameter less than 2.5 μm (PM2.5), which can cause respiratory illnesses in medical personnel. Currently, local exhaust ventilation (LEV) is often used to reduce particles levels. However, LEV generates extra noise and can be easily blocked by blood clots formed during surgery. In this study, we added an ionizer to an electrosurgical pencil to help increase NP removal efficiency and compared the removal efficiency with that of a smoke evacuation pencil. The experiments were performed in an animal surgical facility in which air change rate, relative humidity, and temperature were controlled. We measured the PM2.5 and NP concentrations near the source and in the breathing zone. The ionizer alone, wall suction, smoke evacuation pencil, and wall suction plus ionizer reduce NP number concentrations by 80.1%, 84.5%, 90.3%, and 92.4%, respectively in the breathing zone. The respective reductions in PM2.5 were 86.5%, 92.9%, 93.0%, and 97.2%. Similar PM2.5 and NP removal efficiency was seen near the source. Wall suction plus ionizer shows the highest removal efficiency for NP and PM2.5, but the removal efficiency is not significantly higher (p > 0.05) than the commercial smoke evacuation pencil and wall suction. Moreover, excess lifetime carcinogenic risk also decreased by 79.1%, 90.7%, 93.0%, and 95.6% for the negative ions (NI), wall suction, smoke evacuation pencil, and NI + wall suction, respectively. The newly developed surgical smoke removal devices help reduce particle concentrations and thus can help protect the health of medical personnel.

The ortho, meta, and para isomers of hydroxybenzyl alcohol can be unequivocally distinguished by the collision‐induced dissociation mass spectra of their anions. The presence of a prominent peak at m/z 121 for an elimination of a dihydrogen molecule renders the ortho‐isomer spectrum markedly different from those of its meta and para congeners. Investigations carried out with deuterium‐labeled isotopologues of the ortho isomer verified that the labile hydrogen atom on the hydroxyl group and one of the benzylic hydrogen atoms are specifically removed in the formation of the m/z 121 ion. The ortho‐isomer spectrum also showed a prominent peak at m/z 93. Experimental data indicated that the m/z 93 product ion originates either from a two‐step H2and CO elimination mechanism or from a direct loss of a HCHO molecule from the precursor anion. The intensity ratio of the m/z 93 and 94 peaks in the spectrum recorded from the m/z 124 ion generated from a sample of o‐hydroxybenzyl alcohol dissolved in D2O supported the notion that the direct HCHO loss is the more dominant pathway for the generation of the phenolate ion under low activation conditions. In contrast, the two‐step mechanism becomes the more dominant pathway under high collisional activation conditions. The spectrum also showed a weak peak at m/z 105 for a water loss. Based on computational data, the m/z 105 ion generated in this way appears to be a composite generated from a common ion‐neutral complex intermediate in which a hydroxyl anion is positioned equidistantly between one of the benzylic hydrogens and a nearby hydrogen atom of the benzene ring. Upon activation, the complex dissociates to form either a phenide or a quinone methide anion. The reaction forming a carbon dioxide adduct under ion‐mobility conditions was used to support the proposed water‐loss mechanism. [ABSTRACT FROM AUTHOR]

Introduction/purpose: At altitudes of 80 to 40 km, while the spacecraft made of duralumin without a thermal-protective coating was descending from the flight orbit at the first and second cosmic velocities, data were obtained on the increase in density, pressure, and temperature behind the shock front, as well as on the backout of the shock wave from the surface of the descending spacecraft. Methods: Calculations were made of the energy fluxes on the surface of the spacecraft for every 10 km, for convective and radiative heat transfer, as well as for the impact of electrons produced due to ionization of negative ions. Results: At the first cosmic velocity, the greatest energy flux is realized under the influence of an electron flux, and at the second cosmic velocity, radiative heat transfer occurs. In the shock-compressed gas at all the considered altitudes, pressure increases instantly to a value of 109 ÷ 1011 Pa, which leads to a sequential explosion with increasing power resulting in shock waves in the surrounding atmosphere and compression waves in the entire aircraft structure. The last most powerful explosion occurs at an altitude of approx. 40 km. Conclusion: The descending aircraft is destroyed into separate small parts to the size of small dust particles.

The pandemic of respiratory diseases, such as coronavirus disease 2019 (COVID-19) and influenza, has imposed significant public health and economic burdens on the world. Wearing masks is an effective way to cut off the spread of the respiratory virus. However, due to cultural differences and uncomfortable wearing experiences, not everyone is willing to wear masks; there is an urgent need to find alternatives to masks. In this study, we tested the disinfection effect of a portable ionizer on pandemic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (strain V34) and influenza A virus (strain CA04). Negative ions significantly reduced the concentration of particulate matter in the air above and effectively disinfected viruses stuck to the solid plate at the level of both nucleic acid and virus titer. The disinfection efficiency was >99.8% after 1-h exposure. Moreover, negative ions effectively disinfected aerosolized viruses; the disinfection efficiency was more than 87.77% after purification for 10 min. Furthermore, negative ions had a significant protective effect on susceptible animals exposed to viral aerosols. When the negative ionizer was switched from off to on, the inhalation 50% infective dose (ID50) for golden hamsters challenged with SARS-CoV-2 rose from 9.878 median tissue culture infective dose (TCID50) [95% confidence interval (CI), 6.727–14.013 TCID50] to 43.891 TCID50 (95% CI, 29.31–76.983 TCID50), and the inhalation ID50 for guinea pigs challenged with influenza A virus rose from 6.696 TCID50 (95% CI, 3.251–9.601 TCID50) to 28.284 TCID50 (95% CI, 19.705–40.599 TCID50). In the experiment of transmission between susceptible animals, negative ions 100% inhibited the aerosol transmission of SARS-CoV-2 and influenza A virus. Finally, we tested the safety of negative ion exposure. Balb/c mice exposed to negative ions for 4 weeks showed no abnormalities in body weight, blood routine analysis, and lung pathology. Our study demonstrates that air ions can be used as a safe and effective means of blocking respiratory virus transmission and contribute to pandemic prevention and control. [ABSTRACT FROM AUTHOR]

In this study, a mathematical method is proposed for calculating the concentration field of air ions of different polarities and dust levels in the passenger compartment, taking into account the geometry of the passenger compartment and seats, shelves, and other internal elements of the passenger compartment. The method also takes into account changes in the rate of the air flow ventilation, the location and number of ionizers, and sources of positive ions and dust, taking into account their different intensities and locations. On the basis of a numerical model for this method, software has been developed that allows users to carry out computational experiments without requiring much time for calculation. Based on the results, the optimal location of the ionizer in the passenger compartment of the car was determined to ensure comfortable conditions for the stay of passengers, which favorably affects their health. It has been found that the presence of two ionizers is optimal for creating comfort in the car with an ionization intensity of Qn = 0.47.1010 located at the top of the car. If there is one ionizer located on the dashboard or at the top of the car with a higher ionization rate than Qn = 0.21.1011 ions/s, it is not possible to simultaneously provide optimal ionization parameters for passengers in the front and rear seats of the car. [ABSTRACT FROM AUTHOR]

In recent years, with the improvement of living standards, people’ s health awareness has been constantly enhanced. In addition to requiring beautiful and durable textiles, people have also put forward requirements for the health care of textiles. As a result, the development of health care textiles becomes a trend. As a kind of modified protein fiber, soybean protein fiber with many advantages of both chemical fiber and natural fiber, as well as the health care property of generating negative ions, emitting far infrared and resisting ultraviolet rays, has become an excellent choice for developing health care textiles. However, at present, the domestic and foreign research on soybean protein fiber fabric mainly focuses on its basic wearability, while there are few studies on its functional performance, lacking relevant literature as the reference for the development of health care soybean protein fiber fabric. In order to explore the health care property of soybean protein fiber and provide basis for developing soybean protein fiber fabric in the future, we carried out a series of experiments. In this paper, the cross section and longitudinal morphology of soybean protein fiber were observed by scanning electron microscopy, and then, two groups of soybean protein fiber intertexture samples were woven. The negative,ion concentration, far infrared emission and ultraviolet resistant properties of the fabric were tested. In one group, with polyester as the warp yarn and soybean protein fiber and viscose as the weft yarn, fabrics were woven at the weft insertion ratio of 0:1, 1:4, 1:3, 1:2, 1:1, 2:1, 3:1, 4:1 and 1,0 with five-heddle satin weaves, respectively. The effects of changes in soybean protein fiber content on the above three properties of the fabric were investigated. In the other group, with polyester as the warp yarn andsoybean protein fiber and viscose as the weft yarn, and a weft insertion proportion of 1,1, a total of six kinds of different fabric weaves of plain, four-heddle broken twill, honeycomb weave, 2 / 1 twill, eight-heddle weft satin and five-heddle weft satin were woven respectively. The influence of fabric weave on the above three properties of soybean protein fiber intertexture was investigated. By analyzing the test results, the following conclusions are drawn: the cross section of soybean protein fiber is ovaloid with skin core structure, and the fiber has obvious longitudinal grooves, and the surface is not smooth, which makes the soybean protein fiber have soft luster and good moisture conductivity. The negative,ion concentration, far infrared emission and ultraviolet resistant property of soybean protein fiber intertexture are positively correlated with soybean protein fiber content. When the weft yarn is made of soybean protein fiber, the three properties of the intertexture are the best. Fabric weave has a certain effect on the health care property of soybean protein fiber intertexture. In samples with different fabric weaves, honeycomb weave exhibits the best negative,ion concentration and far-infrared property and the worst ultraviolet resistant property. Eight-heddle satin weave has the best ultraviolet resistant property and the worst far,infrared property, and the negative,ion concentration of plain weave is the least. Through the comprehensive analysis of fuzzy mathematics, eight,heddle satin weave is the best among the three. The negative-ion concentration, far infrared emission and ultraviolet resistant property of soybean protein fiber intertexture in this paper have reached the corresponding national standards, indicating that soybean protein fiber has good health care property. This paper studies and verifies the health care property of soybean protein fiber intertexture. The research results can provide some references for developing soybean protein fiber fabrics that both meet the market requirements and meet people’s needs for health care textiles. [ABSTRACT FROM AUTHOR]

The pandemic of respiratory diseases, such as coronavirus disease 2019 (COVID-19) and influenza, has imposed significant public health and economic burdens on the world. Wearing masks is an effective way to cut off the spread of the respiratory virus. However, due to cultural differences and uncomfortable wearing experiences, not everyone is willing to wear masks; there is an urgent need to find alternatives to masks. In this study, we tested the disinfection effect of a portable ionizer on pandemic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (strain V34) and influenza A virus (strain CA04). Negative ions significantly reduced the concentration of particulate matter in the air above and effectively disinfected viruses stuck to the solid plate at the level of both nucleic acid and virus titer. The disinfection efficiency was >99.8% after 1-h exposure. Moreover, negative ions effectively disinfected aerosolized viruses; the disinfection efficiency was more than 87.77% after purification for 10 min. Furthermore, negative ions had a significant protective effect on susceptible animals exposed to viral aerosols. When the negative ionizer was switched from off to on, the inhalation 50% infective dose (ID50) for golden hamsters challenged with SARS-CoV-2 rose from 9.878 median tissue culture infective dose (TCID50) [95% confidence interval (CI), 6.727–14.013 TCID50] to 43.891 TCID50 (95% CI, 29.31–76.983 TCID50), and the inhalation ID50 for guinea pigs challenged with influenza A virus rose from 6.696 TCID50 (95% CI, 3.251–9.601 TCID50) to 28.284 TCID50 (95% CI, 19.705–40.599 TCID50). In the experiment of transmission between susceptible animals, negative ions 100% inhibited the aerosol transmission of SARS-CoV-2 and influenza A virus. Finally, we tested the safety of negative ion exposure. Balb/c mice exposed to negative ions for 4 weeks showed no abnormalities in body weight, blood routine analysis, and lung pathology. Our study demonstrates that air ions can be used as a safe and effective means of blocking respiratory virus transmission and contribute to pandemic prevention and control.

The ion energies and fluxes in the high power impulse magnetron sputtering plasma from a Nb target were analysed angularly resolved along the tangential direction of the racetrack. A reactive oxygen-containing atmosphere was used as such discharge conditions are typically employed for the synthesis of thin films. Asymmetries in the flux distribution of the recorded ions as well as their energies and charge states were noticed when varying the angle between mass-energy analyser and target surface. More positively charged ions with higher count rates in the medium energy range of their distributions were detected in +EB than in -EB direction, thus confirming the notion that ionisation zones (also known as spokes or plasma bunches) are associated with moving potential humps. The motion of the recorded negatively charged high-energy oxygen ions was unaffected. NbOxthin films at different angles and positions were synthesised and analysed as to their structure and properties in order to correlate the observed plasma properties to the film growth conditions. The chemical composition and the film thickness varied with changing deposition angle, where the latter, similar to the ion fluxes, was higher in +EB than in -EB direction.

The ion energies and fluxes in the high power impulse magnetron sputtering plasma from a Nb target were analysed angularly resolved along the tangential direction of the racetrack. A reactive oxygen-containing atmosphere was used as such discharge conditions are typically employed for the synthesis of thin films. Asymmetries in the flux distribution of the recorded ions as well as their energies and charge states were noticed when varying the angle between mass-energy analyser and target surface. More positively charged ions with higher count rates in the medium energy range of their distributions were detected in +EB than in -EB direction, thus confirming the notion that ionisation zones (also known as spokes or plasma bunches) are associated with moving potential humps. The motion of the recorded negatively charged high-energy oxygen ions was unaffected. NbOxthin films at different angles and positions were synthesised and analysed as to their structure and properties in order to correlate the observed plasma properties to the film growth conditions. The chemical composition and the film thickness varied with changing deposition angle, where the latter, similar to the ion fluxes, was higher in +EB than in -EB direction.

The dissociation of negative molecular ions of tetracyanoquinodimethane (TCNQ) on the surface of the ionization chamber of the ion source of a mass spectrometer modified for operation in the mode of resonant electron capture by molecules is studied. Based on the helium-puffing experiment and calculations by the B3LYP/6-31G method, it is shown that, under the influence of the induced charge, TCNQ– ions on the surface can dissociate through channels which is not possible in the gas phase due to lack of energy. The result is significant for improving the experiment on the resonant capture of electrons by molecules and solving the well-known problem of the destruction of materials based on TCNQ in electronic devices. [ABSTRACT FROM AUTHOR]

Durability indicators of products operating in extreme conditions largely depend on their working part material properties, the properties of the surface layer in particular. For the purposeful formation of these properties, the method of the surface layer exposure to a gas discharge of low-temperature plasma formed by the interaction of microwave electromagnetic and electrostatic fields has been developed directly around the product surface. As a result of this impact, a significantly harder structure may form in the surface layer due to consolidation of the surface layer material. The paper presents a study performed to answer the question about the mechanism that leads to the consolidation. The results showed that this mechanism is mostly related to local thermal effect on the surface layer that occurs due to the neutralization of negative ions, molecules, and molecular complexes formed in plasma. Ion formation depends on the appearance of slow electrons with energy of about 0–3.5 eV in the plasma. Maximum mechanism impact is achieved while ensuring a high rate of negative ion and molecule formation and attaining their maximum concentration on the surface. In this regard, to ensure the formation of negative ions and molecules, it is necessary, firstly, to select a technological mixture of gases in which plasma effects the surface so that it contains atoms and molecules that have high electron affinity, and secondly, to control the energy level of the microwave electromagnetic field. Practical implementation of these recommendations allowed the average 2.0–2.3-fold increase of the real product endurance. [ABSTRACT FROM AUTHOR]

Introduction/purpose: A supersonic flow around a sphere with a radius of 1m at altitudes of 80 to 40 km was analysed. Methods: The descent trajectory at the first cosmic velocity, similar to that of the Soyuz spacecraft with a duralumin structure without thermal protection, was taken into consideration. Results: For the gas between the shock wave front and the surface of the descending spacecraft, data were obtained on the increase in density, pressure, and temperature behind the shock wave front as well as the shift of the shock wave from the surface of the descending spacecraft. The effective temperature of the shock-heated gas reaches its maximum value of 7340 K at an altitude of 60 km. At altitudes of 80 and 40 km, the effective temperature is 7000 K and 6400 K, respectively. Based on the obtained data on the thermodynamic state of the gas behind the shock wave every 10 km, calculations were made of energy fluxes to the surface of the spacecraft for convective and radiative heat transfer, as well as for the impact of electrons produced due to ionization of negative ions. Radiative heat transfer has proven to be the most significant.The burning mechanism of negative ions of triatomic molecules of aluminium with the formation of AlO molecules was determined, and data on pressure rise in the boundary layer on the spacecraft surface were obtained. At all considered altitudes, the pressure rises instantly: to 1.06×1010 Pa at an altitude of 80 km, 5.3×109 Pa at an altitude of 60 km, and reaches the maximum value of 5.5×1010 Pa and an altitude of 40 km. A pressure of 109 to 1010 Pa arises during explosion of various explosives. The energy flux reaches the spacecraft surface between explosions. At the moment of explosion, shock waves develop in the atmosphere surrounding the surface of the descending spacecraft, and compressive waves develop in the entire structure of the spacecraft. The descending spacecraft cracks, and its entire structure breaks down into parts. The area of interaction increases sharply, and each subsequent explosion has a greater intensity and size. As a result, the last most intense explosion occurs at an altitude of approx. 40 km, after which individual fragments of the spacecraft fall to Earth. Conclusion: The exploration of space with flight to other planets is possible only after a thorough study of explosive processes taking place on the surface of the spacecraft descending on other planets, and especially on Earth.

Neutral beam injectors are based on the neutralization of ion beams accelerated at the desired energy. In the case of the ITER heating and diagnostic neutral beams, the target heating power translates into stringent requirements on the acceptable beamlet divergence and aiming to allow the beam to reach the fusion plasma. The beamlets composing the accelerated beam are experimentally found to feature a transverse velocity distribution exhibiting two Gaussian components: the well-focused one is referred to as the core component while the rest of the beam, the halo, describes beam particles with much worse optics. The codes that simulate beam extraction and acceleration usually assume that the negative ions move towards the plasma meniscus with a laminar flow (no transverse velocity) or that the transverse velocity distribution can be modelled as a Maxwellian and that the current density is uniformly illuminating the meniscus; under such approximations, the presence of highly divergent components cannot be explained. In this work, we develop a simple test-particle tracing code with Monte Carlo collisions, named ICARO (for Ions Coming Around), to study the transport of negative ions in the extraction region and derive the spatial and velocity distribution of the negative ions at the meniscus (i.e. the plasma boundary where a beamlet is extracted). In particular, the origin of the beamlet halo and its dependence on the source parameters are discussed, highlighting as a key parameter the energy distribution of positive ions in the source plasma.

We propose a low-density discharge plasma model that takes into account the impact of oxygen admixture in typical conditions of complex (dusty) plasmas. Numerical simulations based on this model show that the concentration of negative ions turns out to be very high, and they play an important role in the overall kinetics in this particular range of plasma conditions. The ambipolar diffusion electric field drags these negative ions into the center of the plasma. The density of negative ions is high enough to push the negatively charged dust component out of the center, both by weakening the radial electric field and by increasing the thermophoretic force. This phenomenon was observed in the published experiment and qualitatively supports the proposed model. Additionally, the proposed model allows an alternative explanation of the experiment.

Field ionization (FI), field desorption (FD), and liquid injection field desorption/ionization (LIFDI) provide soft positive ionization of gaseous (FI) or condensed phase analytes (FD and LIFDI). In contrast to the well-established positive-ion mode, negative-ion FI or FD have remained rare exceptions. LIFDI provides sample deposition under inert conditions, i.e., the exclusion of atmospheric oxygen and water. Thus, negative-ion LIFDI could potentially be applied to highly sensitive anionic compounds like catalytically active transition metal complexes. This work explores the potential of negative-ion mode using modern mass spectrometers in combination with an LIFDI source and presents first results of the application of negative-ion LIFDI-MS. Experiments were performed on two orthogonal-acceleration time-of-flight (oaTOF) instruments, a JEOL AccuTOF GCx and a Waters Micromass Q-TOF Premier equipped with LIFDI sources from Linden CMS. The examples presented include four ionic liquids (ILs), i.e., N-butyl-3-methylpyridinium dicyanamide, 1-butyl-3-methylimidazolium tricyanomethide, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, and trihexyl(tetradecyl)phosphonium tris(pentafluoroethyl)trifluorophosphate), 3-(trifluoromethyl)-phenol, dichloromethane, iodine, polyethylene glycol diacid, perfluorononanoic acid, anionic surfactants, a tetraphosphazene silanol-silanolate, and two bis(catecholato)silanes. Volatile samples were delivered as vapors via the sample transfer capillary of the LIFDI probe or via a reservoir inlet. Condensed phase samples were applied to the emitter as dilute solutions via the sample transfer capillary. The compounds either yielded ions corresponding to their intact anions, A−, or the [M–H]− species formed upon deprotonation. This study describes the instrumental setups and the operational parameters for robust operation along with a discussion of the negative-ion LIFDI spectra of a variety of compounds. [ABSTRACT FROM AUTHOR]

The enhancement of negative ion production in a volume Penning based source could be performed by the application of metal hydride cathode. Hydrogen isotopes are stored there in a chemically bound atomic state and desorbed from the metal hydride under the discharge current impact. Highly vibrationally / rotationally excited molecules H2* are formed by recombination of H-atoms at the metallic surface, which then can be easily converted to H– by dissociative electron attachment without the pre-excitation of a H2 molecule in plasma. Changing the discharge properties opens the way of source design simplification by negative ions extraction along the external magnetic field in comparison with traditional volume sources, where the extraction is performed perpendicular to magnetic field. The separation of negative ions from the extracted in longitudinal direction flux of charged particles was performed by an electromagnetic filter basing on numerical calculations of particles trajectories. The dependence of electron temperature and plasma density on the bias potential is carried out by Langmuir probe method. The measurement of electron energy was performed by an electrostatic energy analyzer. It was shown that the yield of H– ions depends on the electrical bias on the metal hydride cathode with strong dependences on the plasma electrons temperature. The estimation of the bias potential versus Te was performed under the assumption of electron Boltzmann distribution near the cathode. The presence of additional groups of electrons with higher energies distorts the behavior of H– current, but generally the experimental results are in good agreement with estimation based on the physics behind the Boltzmann distribution. The optimum for the effective extraction of H– ions was revealed, when the metal hydride cathode had been electrically biased at -20V and higher, and plasma density reaches the maximum value to 2×109 cm-3.

Introduction/purpose: At altitudes of 80 to 40 km, while the spacecraft made of duralumin without a thermal-protective coating was descending from the flight orbit at the first and second cosmic velocities, data were obtained on the increase in density, pressure, and temperature behind the shock front, as well as on the backout of the shock wave from the surface of the descending spacecraft. Methods: Calculations were made of the energy fluxes on the surface of the spacecraft for every 10 km, for convective and radiative heat transfer, as well as for the impact of electrons produced due to ionization of negative ions. Results: At the first cosmic velocity, the greatest energy flux is realized under the influence of an electron flux, and at the second cosmic velocity, radiative heat transfer occurs. In the shock-compressed gas at all the considered altitudes, pressure increases instantly to a value of 109 ÷ 1011 Pa, which leads to a sequential explosion with increasing power resulting in shock waves in the surrounding atmosphere and compression waves in the entire aircraft structure. The last most powerful explosion occurs at an altitude of approx. 40 km. Conclusion: The descending aircraft is destroyed into separate small parts to the size of small dust particles. [ABSTRACT FROM AUTHOR]