Gas Ions Research Articles

Impacts of temperature and turbidity on the gill physiology of darter species

Fish gills are complex organs that have direct contact with the environment and perform numerous functions including gas exchange and ion regulation. Determining if gill morphometry can change under different environmental conditions to maintain and/or improve gas exchange and ion regulation is important for understanding if gill plasticity can improve survival with increasing environmental change. We assessed gill morphology (gas exchange and ion regulation metrics), hematocrit and gill Na+/K+ ATPase activity of wild-captured blackside darter (Percina maculata), greenside darter (Etheostoma blennioides), and johnny darter (Etheostoma nigrum) at two temperatures (10 and 25 °C) and turbidity levels (8 and 94 NTU). Samples were collected August and October 2020 in the Grand River to assess temperature differences, and August 2020 in the Thames River to assess turbidity differences. Significant effects of temperature and/or turbidity only impacted ionocyte number, lamellae width, and hematocrit. An increase in temperature decreased ionocyte number while an increase in turbidity increased lamellae width. Hematocrit had a species-specific response for both temperature and turbidity. Findings suggest that the three darter species have limited plasticity in gill morphology, with no observed compensatory changes in hematocrit or Na+/K+ ATPase activity to maintain homeostasis under the different environmental conditions.

Research on the influence of gas ionization on pulse forming in linear transformer driver (LTD) electron beam generator

Currently, there is limited research on the influence of gas ionization on the pulse formation process in pulse power source-driven loads. This paper introduces a road-field-Particle-In-Cell (PIC)/Monte Carlo Collision (MCC) collaborative simulation method that can accurately simulate gas ionization in Linear Transformer Driver (LTD) electron beam generation (EBG). The method couples the electromagnetic field and charged particle simulated through PIC/MCC with the circuit modules, and the load's voltammetry characteristics can real-time feedback to the Blumlein Pulse Forming Network (BPFN) of the LTD. In contrast to prior simulations that used fitted ideal T-shaped pulse input waveforms to model the load, this method provides a clearer depiction of the influence of gas ionization on the pulse shape. Additionally, the paper conducts simulation studies on LTD electron beam generator operating at different argon gas pressures. The findings indicate that introducing gas can effectively increase current while reducing voltage amplitude, thereby lowering the diode impedance. A small amount of gas can slightly enhance peak power, but excessive gas diminishes peak power and significantly shortens voltage pulse width. This is attributed to the beneficial effect of a small amount of gas ionization-produced plasma on the device. However, an excessive amount of gas ionization-generated plasma can lead to impedance mismatch in the device, even resulting in a load short circuit. This phenomenon causes a decrease in pressure drop at the top, consequently shortening the pulse width.

Study of the thrust response characteristics of Hall Micro Thruster

An advanced Watt class Hall Micro Thruster (HMT) is offered for Space Gravitational Wave Detection (SGWD), and an investigation has been conducted on its start-up, shutdown, rise, and fall response times. The research involved creating a circuit for thruster discharge and signal acquisition, using a Faraday probe to measure the plasma plume signal generated by the thruster, and characterizing the thrust directly. Ultimately the response time of the thruster is extracted from the discharge current and Faraday current signals. The experimental results demonstrate that the HMT has a response time ranging from 1.08 ms to 16.76 ms at mass flow rates of 0.02 mg/s and 0.04 mg/s, meeting the SGWD requirements for micro thruster response time. This research provides a physical foundation and explanation for the variation of HMT response time with discharge voltage versus mass flow rate with several key parameters that affect HMT plasma discharge, such as neutral gas number density (nn) and ionization mean free path (λi). Furthermore, we have examined several anomalies in the signal. Overall, this research provides a brand-new method for measuring the thrust response time of electric thrusters.

Distribution and Sensory Impact of (2E,4E,6Z)-nonatrienal and Trans-4,5-epoxy-(E)-2-decenal in Wines and Spirits.

This study reports the distribution of (2E,4E,6Z)-nonatrienal (1) and trans-4,5-epoxy-(E)-2-decenal (2) in wines and spirits. We validated a quantification method using solid-phase extraction (SPE) and negative chemical ionization (NCI, NH3) gas chromatography-mass spectrometry (GC-MS) analysis. Both were identified for the first time in wines and spirits from different grape varieties and raw materials. Their olfactory detection thresholds (ODTs) were 16 and 60 ng/L, respectively. Analysis of 66 wines showed that the highest levels of (1) (441.3 ng/L) and (2) (386.5 ng/L) were found in red and white wines, respectively. At these levels, they modify the balance of the fruity expression of red (fresh to cooked fruits) and white (vegetal/green hazelnut nuance) wines. Similar quantitative and sensory analyses were conducted in spirits. With ODT estimated at 500 and 400 ng/L and concentrations ranging from trace amounts to 1.1 and 2.4 μg/L respectively, (1) and (2) can contribute directly to the aroma of spirits.

Chromatographic analysis and antioxidant effect of essential oils from two Algerian Teucrium species: Teucrium flavum L. and Teucrium polium L.

This study aimed to examine the chemical composition and antioxidant activity of essential oils of Teucrium flavum and Teucrium polium, collected from Babor mountains in Algeria. The essential oils were extracted using the hydrodistillation method and analyzed by gas chromatography-flame ionization detector and gas chromatography-mass spectrometry. Fifty-two components were identified in the essential oil of T. flavum representing 91.40% of the total essential oil. Its major components were germacrene D (18.0%) followed by (Z)-γ-bisabolene (10.3%), β-caryophyllene (7.6%), α-pinene (6.7%), β-pinene (6.2%), α-humulene (5.8%) and limonene (5%) with a prevalence of sesquiterpene hydrocarbons (59.1%). However, sixty-four components were identified in the essential oil of T. polium (96.80% of total essential oil). Its major components were germacrene D (36.5%), β-pinene (11.8%), epi-α-cadinol (9%) and bicyclogermacrene (7.3%). Sesquiterpene hydrocarbons constituted the most abundant fraction of this essential oil (55.6%). The antioxidant potential was tested using free radical scavenging activity against 1,1-diphenyl-2-picrylhydrzyl, and β-carotene-linoleic acid assays. Both the essential oils exhibited moderate to low activity. Overall, the essential oil of T. flavum was more effective than that of T. polium.

Ion mobility calculations of flexible all-atom systems at arbitrary fields using two-temperature theory.

Ion mobility spectrometry (IMS) separates and analyzes ions based on their mobility in a gas under an electric field. When the field is increased, the mobility varies in a complex way that depends on the relative velocity between gas and ion, their electrostatic potential interactions, and the effects from direct impingement. Recently, the two-temperature theory, primarily developed for monoatomic ions in monoatomic gases, has been extended to study mobilities at arbitrary fields using polyatomic ions in polyatomic gases, with some success. However, this extension poses challenges, such as inelastic collisions between gas and ion and structural modifications of ions as they heat up. These challenges become significant when working with diatomic gases and flexible molecules. In a previous study, experimental mobilities of tetraalkylammonium salts were obtained using a FAIMS instrument, showing satisfactory agreement with numerical two-temperature theory predictions. However, deviations occurred at fields greater than 100 Td. To address this issue, this paper introduces a modified high-field calculation method that accounts for the structural changes in ions due to field heating. The study focuses on tetraheptylammonium (THA+), tetradecylammonium (TDA+), and tetradodecylammonium (TDDA+) salts. Molecular structures were generated at various temperatures using MM2 forcefield. The mobility was calculated using IMoS 1.13 with two-temperature trajectory method calculations up to the fourth approximation. Multiple effective temperatures were considered, and a linear weighing system was used to create mobility vs. reduced field strength plots. The results suggest that the structural enlargement due to ion heating plays a significant role in mobility at high fields, aligning better with experimental data. FAIMS' dispersion plots also show improved agreement with experimental results. However, the contribution of inelastic collisions and energy transfer to rotational degrees of freedom in gas molecules remains a complex and challenging aspect.

Particle-in-cell-Monte Carlo collision simulation study on breakdown characteristics on gas side of high-power microwave dielectric window

Gas breakdown is one of the key factors restricting the increase of power capacity around the outer surface of highpower microwave dielectric window. It is of great significance to conduct corresponding simulation studies. Compared with the fluid model, the particle-in-cell-Monte Carlo collision model has two advantages: firstly, the influence of numerical dispersion and instability problems is insignificant; secondly, it can accurately describe microphysical processes. Therefore, the breakdown characteristics on gas side of dielectric window are simulated by the particle-in-cell-Monte Carlo collision model. The two-in-one macro-particle merging method is introduced into the model, which greatly reduces the number of macro-particles tracked, so that the whole breakdown process can be simulated and analyzed. The results show that the spatial and temporal evolution of breakdown under the variable macro-particle weight is in good agreement with that under the constant macro-particle weight. This suggests that the two-in-one macro-particle merging method is applicable under the simulation conditions of interest in this paper, i.e., when the ratio of the effective electric field of microwaves to the pressure is between 1:76×103 and 1:41×10<sup>4</sup> V/(m·Torr). Since the yield of secondary electron emission is much less than 1, gas ionization is the dominant mechanism of breakdown on gas side of dielectric window. Electron ionization and diffusion lead to a significant increase in the density and thickness of the plasma over time. The peak of electron density does not appear at the dielectric surface, but at a position 100-150 <i>μ</i>m away from the dielectric surface. This is because a large number of electrons are deposited on the dielectric surface, and the accompanying self-organized normal electric field drives the electrons away from the dielectric surface. Since the background gas pressure of interest in this paper is higher than the critical pressure corresponding to the maximum ionization rate (about 10 Torr), the ionization rate decreases monotonically with increasing pressure and leads to a slower development of breakdown. The accuracy of the particle-in-cell-Monte Carlo collision model is confirmed by comparing the simulated values of breakdown time with experimental data. This work provides an important theoretical basis for understanding and controlling the breakdown on gas side of dielectric window. The following figure (a) shows that the mean electron energy under the variable macro-particle weight agrees well with that under the constant macro-particle weight at 100 Torr. The following figure (b) shows that using the particle-in-cell-Monte Carlo collision model with a two-in-one macro-particle merging method allows the breakdown process to be considered when the plasma density increases by a factor of 108.

Cold plasma treatment for fungal keratitis

Aims/Purpose: Fungal keratitis is serious ocular infection caused by any of the fungi species. It is treated with antifungal medications, in worst scenario with cornea transplantation. The therapy is still challenging due to poor drug penetration into the cornea. Cold plasma, produced by ionization of argon gas, contains especially reactive species but also UV radiation which damage microorganisms. The aim of this study is to determine the effect of cold plasma on human corneal epithelial cells (HCE), corneal tissue and multiple pathogen microorganisms to assess the opportunity of cold plasma treatment for fungal keratitis.Methods: The effect of cold plasma on HCE was analysed by the light microscopy, Live/Dead assay, metabolic activity assay, and immunohistochemistry. Disinfecting potential was analysed by plating prevalent yeasts (Candida albicans, C. krusei, C. parapsilosis, C. glabrata) on agar plates and treated with cold plasma. Plasma treatment of infected human donor corneas with C. albicans was determined by measurement of O.D. of liquid culture.Results: The treatment of HCE by cold plasma led to the change of the morphology, significantly lower viability, metabolic activity and proliferation of the cells. Yeast strains were significantly eradicated completely after 5 min of cold plasma treatment (p ≤ 0.001). Cold plasma therapy of the infected human donor corneas showed the decrease of the infection in all tested time intervals with statistical significance (p ≤ 0.01, p < 0.05 and p ≤ 0.001 respectively for 1, 2 and 5 min treatment).Conclusions: Cold plasma treatment showed negative impact on the culture of HCE. The analysis of its effect on the whole corneal tissue is in progress. On the contrary, a significant reduction of CFU was observed in all examined Candida spp. and significant decrease of infection was determined in infected corneas. Therefore, the cold plasma technology showed a potential to be an effective treatment for fungal keratitis.

Features of the Dynamic Spectrum of Signals Generated by a Wide-Aperture Electron Beam in a Large-Scale Magnetized Plasma

Electromagnetic signals generated by a wide-aperture electron beam in the laboratory plasma under conditions limitedly modeling the interaction between waves and particles in the near-Earth plasma have been studied at the large-scale Krot device. The spectrum of electromagnetic radiation includes whistler noise, which is presumably due to the current instability, and discrete (narrowband) signals near harmonics of the electron cyclotron and plasma frequencies. It has been shown that narrowband signals with a positive frequency drift that are observed at the injection of the electron beam are caused by nonstationary variations of the plasma density due to an additional ionization of a neutral gas by accelerated electrons. These effects should be taken into account to interpret nonconventional forms of the dynamic spectrum in various laboratory experiments simulating processes in the Earth’s ionosphere and magnetosphere.

Generation and reactivity of the fragment ion [B12I8S(CN)]- in the gas phase and on surfaces.

Gaseous fragment ions generated in mass spectrometers may be employed as "building blocks" for the synthesis of novel molecules on surfaces using ion soft-landing. A fundamental understanding of the reactivity of the fragment ions is required to control bond formation of deposited fragments in surface layers. The fragment ion [B12X11]- (X = halogen) is formed by collision-induced dissociation (CID) from the precursor [B12X12]2- dianion. [B12X11]- is highly reactive and ion soft-landing experiments have shown that this ion binds to the alkyl chains of organic molecules on surfaces. In this work we investigate whether specific modifications of the precursor ion affect the chemical properties of the fragment ions to such an extent that attachment to functional groups of organic molecules on surfaces occurs and binding of alkyl chains is prevented. Therefore, a halogen substituent was replaced by a thiocyanate substituent. CID of the precursor [B12I11(SCN)]2- ion preferentially yields the fragment ion [B12I8S(CN)]-, which shows significantly altered reactivity compared to the fragment ions of [B12I12]2-. [B12I8S(CN)]- has a previously unknown structural element, wherein a sulfur atom bridges three boron atoms. Gas-phase reactions with different neutral reactants (cyclohexane, dimethyl sulfide, and dimethyl amine) accompanied by theoretical studies indicate that [B12I8S(CN)]- binds with higher selectivity to functional groups of organic molecules than fragment ions of [B12I12]2- (e.g., [B12I11]- and [B12I9]-). These findings were further confirmed by ion soft-landing experiments, which showed that [B12I8S(CN)]- ions attacked ester groups of adipates and phthalates, whereas [B12I11]- ions only bound to alkyl chains of the same reagents.

Electrical and thermal characteristics of LaB6 thermionic hollow cathodes operating in He, D2, Ar, and Xe at 4–200 Pa and 0.25–5 A cm−2

We report characteristics of lanthanum hexaboride (LaB6) cathodes for conditions relevant to a high-voltage, high-current switching device. LaB6 is selected because of its relatively low work function, stability in the presence of many common gas impurities, and a low evaporation rate (long life) at operating temperatures. We have investigated the effect of cathode geometry, gas type, pressure, and current on a LaB6 hollow cathode in a diode configuration with an opposing planar anode. The gas is stagnant at a relatively low pressure of 4–200 Pa (0.03–1.5 Torr) because of device high-voltage standoff requirements. In all cases, the plasma voltage decreases to a plateau value with increasing current where a practical device would operate. The plateau voltage aligns with the fill gas excitation or ionization voltage, depending on conditions. At high current, the cathode temperature exceeds that required for thermionic emission to supply the total current, a behavior that is understood by accounting for back-diffusing bulk electrons.

Evaluation of Lipid Composition and Nutritional Quality of Olive Oil Varieties Using ESI-MS, GC-FID and Chemometrics Techniques

Olive oil is a highly demanded product renowned for its unique taste and diverse nutrient content, primarily composed of lipids. This study aimed to comprehensively analyze the lipid profiles of four olive varieties (Arbequina, Arbosana, Koroneiki, and Frantoio) and their corresponding commercial olive oils using advanced analytical techniques, namely electrospray ionization mass spectrometry and gas chromatography with flame ionization detector, combined with principal component analysis. The nutritional quality of the olive oils was evaluated based on parameters such as the ratio of saturated acids to polyunsaturated acids, atherogenicity, thrombogenicity, and andhypocholesterolemic/hypercholesterolemic indexes. The study revealed that the primary fatty acids identified were palmitic, stearic, oleic, and linoleic acids, while triolein, palmitodiolein, and stearodiolein emerged as the most abundant triacylglycerol across all samples. Furthermore, the results demonstrated that the commercial olive oil samples exhibited an exceptional nutritional profile. Overall, this study highlights the significance and efficacy of the analytical and statistical techniques employed to unravel the lipid profiles of olive oils, a product of substantial commercial value and susceptible to adulteration. Additionally, it emphasizes the importance of utilizing nutritional quality indices to assess the health benefits associated with olive oil consumption.

Volatile chemical profiling and distinction of Citrus essential oils by GC analyses with correlation matrix; evaluation of its in vitro radical scavenging and microbicidal efficacy

Leaf volatile oil compositions of five Citrus species viz., Citrus aurantifolia, Citrus limon, Citrus maxima, Citrus medica and Citrus medica * Citrus limon were examined in this study by Gas Chromatography-Flame Ionisation Detector (GC-FID) and Gas Chromatography-Mass Spectrometry (GC–MS) analysis and percentage volatile compositions were compared. Thirty-eight compounds were identified that account for 90 to 99 % of essential oil composition from Citrus species, respectively. GC–MS profiling of essential oils revealed that Citrus leaf oils were predominantly characterized by limonene (15.76±0.01% to 29.36±0.46%) as one of the major constituents. Monoterpenoids (77.38±0.19% to 98.05±0.05%) are the prominent class of constituents present in the volatile oils of four Citrus plants under study whereas in one species (C. maxima), sesquiterpene hydrocarbons (38.97±0.21%) were the dominant category. The data from GC analyses were subjected to correlation study to analyse the correlation between the volatile constituents among the selected Citrus species. These essential oils were initially evaluated for their antioxidant capacity and the leaf oils exhibited promising radical scavenging property with an average IC50 value of 29.15±0.01 μg/mL. This study was further designed to evaluate antimicrobial efficacy of five Citrus leaf essential oils against various pathogenic bacterial and fungal strains. Four examined essential oils gave a comparative antibacterial activity with a minimum inhibitory concentration (MIC) value against tested bacterial strains ranging from 3.62±0.02mg/mLto60.0±0.32mg/mL.Citrus leaf oils were found to be more sensitive to Escherichia coli with MIC values ranged between 3.62±0.03 to 10.15±0.02 mg/mL. These essential oils also exhibited strong inhibitory potential against tested fungal strains, Aspergillus niger and Candida albicans, with MIC ranging from 3.22±0.02 to 28.17±0.04 mg/mL. Out of the five essential oils screened in this study, four of them have shown significant antimicrobial and antioxidant activities which can be attributed to synergistic potential of major monoterpenoid constituents present in these oils viz., geranial, neral, citronellal, nerol, geraniol, geranyl formate rather than the sesquiterpene dominated essential oil. Based on the findings obtained and conclusions derived, it is evident that the selected Citrus leaf essential oils are promising natural agents to fight free radical damage and antibiotic-resistant microbes.

Ion emission from 1-10 MDa salt clusters: individual charge state resolution with charge detection mass spectrometry.

Salt cluster ions produced by electrospray ionization are used for mass calibration and fundamental investigations into cluster stability and charge separation processes. However, previous studies have been limited to relatively small clusters owing to the heterogeneity associated with large, multiply-charged clusters that leads to unresolved signals in conventional m/z spectra. Here, charge detection mass spectrometry is used to measure both the mass and charge distributions of positively charged clusters of KCl, CaCl2, and LaCl3 with masses between ∼1 and 10 MDa by dynamically measuring the energy per charge, m/z, charge, and mass of simultaneously trapped individual ions throughout a 1 s trapping time. The extent of remaining hydration on the clusters, determined from the change in the frequency of ion motion with time as a result of residual water loss, follows the order KCl < CaCl2 < LaCl3, and is significantly lower than that of a pure water nanodrop, consistent with tighter water binding to the more highly charged cations in these clusters. The number of ion emission events from these clusters also follows this same trend, indicating that water at the cluster surface facilitates charge loss. A new frequency-based method to determine the magnitude of the charge loss resulting from individual ion emission events clearly resolves losses of +1 and +2 ions. Achieving this individual charge state resolution for ion emission events is an important advance in obtaining information about the late stages of bare gaseous ions formation. Future experiments on more hydrated clusters are expected to lead to a better understanding of ion formation in electrospray ionization.

A modular table-top setup for ultrafast x-ray diffraction.

We present a table-top setup for femtosecond time-resolved x-ray diffraction based on a Cu Kα (8.05keV) laser driven plasma x-ray source. Due to its modular design, it provides high accessibility to its individual components (e.g., x-ray optics and sample environment). The Kα-yield of the source is optimized using a pre-pulse scheme. A magnifying multilayer x-ray mirror with Montel-Helios geometry is used to collect the emitted radiation, resulting in a quasi-collimated flux of more than 105 Cu Kα photons/pulse impinging on the sample under investigation at a repetition rate of 10Hz. A gas ionization chamber detector is placed right after the x-ray mirror and used for the normalization of the diffraction signals, enabling the measurement of relative signal changes of less than 1% even at the given low repetition rate. Time-resolved diffraction experiments on laser-excited epitaxial Bi films serve as an example to demonstrate the capabilities of the setup. The setup can also be used for Debye-Scherrer type measurements on poly-crystalline samples.

Reliability Assessment of Indium Micro Bumps for 2.5D/3D Electronic Packaging Through Cryo-Argon Milling Technique

Indium bumps are widely used in electronic packaging for interconnecting microelectronic devices due to their low melting point of 156.6 degrees C, excellent bonding capabilities at room temperature, high thermal conductivity, ductility at extremely low temperatures, and ability to compensate for the mismatched coefficient of thermal expansion between different materials. However, cross-sectioning indium bumps can be challenging due to the softness and low melting point of indium. The cutting tools and techniques used must be optimized for the specific sample being analyzed, and specialized preparation techniques such as cryogenic freezing or chemical etching may be required, which can be expensive and time-consuming. Cryo-focused ion beam (FIB) is also a technically demanding process that requires careful optimization of milling parameters, multiple iterations of milling and imaging, specialized equipment, and expertise, which can make it too expensive. It should be noted that the maximum achievable crosssectional area with cryo-FIB is limited, typically in the range of hundreds of micrometers. Cryo-Argon milling is an effective technique for obtaining high-quality cross-sections of indium bump arrays and other materials prone to deformation or melting during traditional crosssectioning. This process involves freezing the sample using liquid nitrogen and bombarding it with a stream of Argon gas ion, which reduces the deformation and melting of the indium. This paper presents challenges in the sample preparation and mechanical polishing of indium micro bumps. We are showcasing an artifact: polishing particles embedded in the indiummicro bumps, hindering the revelation of their microstructure. To address this issue, we are incorporating cryo-Ar milling to remove the embedded particles from the surface of indium micro bumps. This work presents data before and after the application of cryo-Ar milling, demonstrating a significant improvement in the microstructure of indium micro bumps. Millimeter-wide, damage-free cross-sections of arrays of indium micro bumps with a clean and smooth surface were achieved through cryo-Argonmilling at270 degrees C.

Effect of V/Mo Atomic Ratio on the Microstructure and Mechanical Properties of MoVCuN Coatings.

To improve the gas ionization ratio, the Mo-V-Cu-N coatings were deposited by pulsed dc magnetron sputtering with assistance from an anode layer ion source, and the influence of the V/Mo atomic ratio was explored with regard to the microstructure and mechanical properties of the coatings. The findings of this study indicated that the MoVCuN coatings exhibited a solid solution phase of FCC B1-MoVN with a prominent (220) preferred orientation, and the deposition rate was found to decrease from 4.7 to 1.8 nm/min when the V/Mo atomic ratio increased. The average surface roughness of the MoVCuN coatings gradually decreased, and the lowest surface roughness of 6.9 nm was achieved at a V/Mo atomic ratio of 0.31. Due to the enhanced ion bombardment effect, the coatings changed from a coarse columnar to a dense columnar crystal structure, and promoted grain refinement at higher V/Mo atomic ratios, contributing to a gradual improvement in the compressive residual stress, hardness and adhesion strength of the coatings.

Paticularities of radiation defect formation in ceramic barium cerate

The results of the investigations are presented on the effect of irradiation with electrons, ions of inert gases (Ne, Ar, Kr) and oxygen on the structure and properties of Nd-doped barium cerate by the methods of X-ray diffraction analysis, scanning electron and atomic force microscopy, thermal desorption spectroscopy. It is shown that the low-energy irradiation with Ne and Ar ions stimulates the blistering processes on the surface, whereas the high energy ion irradiation by Ne, Ar, Kr ions the cerate surface undergoes the following stages of the spherulite growth - nucleation, growth (view of cauliflower), formation of spherulitic crust, correspondingly. The similar structures were not observed in the case of irradiation with high-energy oxygen ions. It is noticed that the irradiation of cerates with electrons leads to the formation of nano-sized acicular structures on the surface. The radiation of lowenergy ions of inert gases led to the conversion of most of the neodymium into a tetravalent state, as has been shown, accompanied by an increase in oxygen release and a decrease in water compared to non-irradiated cerate, as well as the independence of the amount of gases from the type of ions. Based on the data on thermal desorption of water and oxygen molecules from the irradiated barium cerate it was assumed that the irradiation stimulates the oxidation to Nd4+.

Spectromicroscopy Study of Induced Defects in Ion-Bombarded Highly Aligned Carbon Nanotubes.

Highly aligned multi-wall carbon nanotubes were investigated with scanning electron microscopy (SEM), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) before and after bombardment performed using noble gas ions of different masses (argon, neon and helium), in an ultra-high-vacuum (UHV) environment. Ion irradiation leads to change in morphology, deformation of the carbon (C) honeycomb lattice and different structural defects in multi-wall carbon nanotubes. One of the major effects is the production of bond distortions, as determined by micro-Raman and micro-X-ray photoelectron spectroscopy. We observe an increase in sp3 distorted bonds at higher binding energy with respect to the expected sp2 associated signal of the carbon 1s core level, and increase in dangling bonds. Furthermore, the surface damage as determined by the X-ray photoelectron spectroscopy carbon 1s core level is equivalent upon bombarding with ions of different masses, while the impact and density of defects in the lattice of the MWCNTs as determined by micro-Raman are dependent on the bombarding ion mass; heavier for helium ions, lighter for argon ions. These results on the controlled increase in sp3 distorted bonds, as created on the multi-wall carbon nanotubes, open new functionalization prospects to improve and increase atomic hydrogen uptake on ion-bombarded multi-wall carbon nanotubes.

Effect of noble gases ion implantation on the life time of WC-Co tools usedin wood-based material machining

Effect of noble gases ion implantation on the life time of WC-Co tools used in wood-based materialmachining. The results of the investigations on the tool life of WC-Co tools, implanted with three noble gas ions,i.e. helium, neon and argon, are presented in the comparison with the virgin tools and tools implanted withnitrogen ions. The surface modification of the tools was preceded by the modelling of the depth profiles of theimplanted elements. The implantation of the ions of noble gases resulted in an improvement in tool tool life, inthe range from 5 to 49%.