Noble Gas Research Articles

Seiichi Iwamatsu, the Inventor of Atomic Layer Etching: The Conception of Cycled Exposures of Silicon to Halogens and Pulses of Heat, Ions, and More

The history of Atomic Layer Deposition (ALD) has been extensively researched in the VPHA-project (www.vph-ald.com/) initiated in 2013 by R. Puurunen [1]. It is commonly accepted that Atomic Layer Deposition (ALD) was conceived in the Baltic area as a unique ultrathin-film growth method based on the repeated, self-terminating gas-solid half-reactions of at least two volatile compounds on a solid substrate surface. Originally, in the 1960’s, the Russians Alekskovski and Kol'tsov [2]) named this method Molecular Layering and exactly 50 years ago, in 1974 the Finnish inventors Suntola and Antson [3] patented the method as Atomic Layer Epitaxy. This fact has been officially celebrated at the 24th ALD Conference in Helsinki (Aug. 5, ’24 ald2024.avs.org).Atomic Layer Etching (ALE) has lagged behind ALD. For long [4,5] the first patent published on ALE was thought to have been initiated by Max Yoder [6]. In 1987 he conceived the idea on diamond etching with intermittent pulsing of nitrogen dioxide and noble gas ions mixed with hydrogen gas. However, it was Seiichi Iwamatsu (Fig. 1) of Seiko Epson, Japan, who filed in 1981 an application on Si-etching by repeated exposure to iodine (I2) chemistry at moderate temperatures (20 °C to 100 °C) followed by a light or heat pulse up to ~ 300 °C [7]; see Fig. 2. This patent was followed by several others on ALE [8]. One of these patents disclosed quasi-ALE (named “digital etching”) via Si-surface modification by “lamination” of a single Cl-atomic layer from exposure to Cl2 gas, followed by a removal step carried out by Ar+-ion bombardment to etch off “one atomic layer or at most three atomic layers by controlling the kinetic energy” [9].This presentation will highlight the groundbreaking work and background of the Japanese inventor Seiichi Iwamatsu. Born in 1939 in Kyoto to a family of doctors - his father being a practicing physician- he grew up and studied in Osaka, after which he spent many years as a ‘master inventor’ (over 1200 patents filed in his name) for Seiko Epson (~1970-1990) and others afterwards. He played key roles in thin-film technology and e-beam lithography. He also contributed to the success story of Seiko’s quartz watch, a masterpiece in micromachining a miniature tuning fork from crystalline fused silica, tuning/trimming it to 32,768 Hz (=215 Hz), packaging it in a hermetically sealed case and integrating it with flip-flop frequency dividing and counting electronic circuitry and a step motor [10].From the above it is clear that Mr. Iwamatsu can be recognized as the original inventor of Atomic Layer Etching.----------------------------------------------------AcknowledgementThe authors would like to thank Dr. Masanobu Honda (Tokyo Electron Miyagi Ltd., Japan) for his support in retrieving some of the historic facts mentioned herewith about Dr. Iwamatsu.

Tailoring Superatomic Stability with Transition Metals in Silicon Cages: Shrinking to M@Si15 (M = Re, Os, Ir).

The design of materials with intriguing electronic properties is crucial for advancing nanoscale technologies, where precise control over atomic structure and electronic behavior is essential. Metal-encapsulating silicon cage superatoms (SAs) provide a new paradigm for molecular-scale material design, allowing fine-tuning of both structure and electronic characteristics. The formation of superatoms mimicking halogens, noble gases, and alkali metals has been well-studied, particularly with M@Si16, where early transition metals from groups 3 to 5 stabilize within a Si16 cage, achieving a 68-electron configuration. For late transition metals with excess electrons, a Si15 cage offers enhanced stability by fulfilling the 68-electron rule with one fewer Si atom. This research synthesizes Si15 cage-SAs with rhenium (Re) from group 7 and iridium (Ir) from group 9 on p-type and n-type organic substrates. The stability of Re@Si15 and Ir@Si15 is evaluated via oxidative reactivity with X-ray photoelectron spectroscopy and theoretical calculations, including osmium (Os) from group 8. Re@Si15-, Os@Si150, and Ir@Si15+ exhibit superatomic behaviors similar to halogens, noble gases, and alkali metals due to the 68-electron shell closure. Among them, Re@Si15- on p-type organic substrates shows superior electronic and geometric properties. These findings advance our understanding of M@Sin systems for transition metals, addressing longstanding questions about their properties at n = 15 and 16.

Experimental and Theoretical Insights on Gas Trapping of Noble Gases in MFU-4-Type Metal-Organic Frameworks.

Isostructural metal-organic frameworks (MOFs), namely MFU-4 and MFU-4-Br, in which the pore apertures are defined by anionic side ligands (Cl- and Br-, respectively), were synthesized and loaded with noble gases. By selecting the type of side ligand, one can fine-tune the pore aperture size, allowing for precise regulation of the entry and release of gas guests. In this study, we conducted experiments to examine gas loading and release using krypton and xenon as model gases, and we complemented our findings with computational modeling. Remarkably, the loaded gas guests remained trapped inside the pores even after being exposed to air under ambient conditions for extended periods, in some cases for up to several weeks. Therefore, we focused on determining the energy barrier preventing gas release using both theoretical and experimental methods. The results were compared in relation to the types of hosts and guests, providing valuable insights into the gas trapping process in MOFs, as well as programmed gas release in air under ambient conditions. Furthermore, the crystal structure of MFU-4-Br was elucidated using the three-dimensional electron diffraction (3DED) technique, and the bulk purity of the sample was subsequently verified through Rietveld refinement.

Shallow defects and optical properties of CsPbBr3 thin films through noble gas ion beam defect engineering

Ion implantation is widely utilised for the modification of inorganic semiconductors; however, the technique has not been extensively applied to lead halide perovskites. In this report, we demonstrate the modification of the optical properties of caesium lead bromide (CsPbBr3) thin films via noble gas ion implantation. We observed that the photoluminescence (PL) lifetimes of CsPbBr3thin films can be doubled by low fluences (<1 × 1014at·cm-2) of ion implantation with an acceleration voltage of 20 keV. We attribute this phenomenon to ion beam induced shallow minority charge carrier trapping induced by nuclear stopping, dominant by heavy noble gases (Ar, Xe). Simultaneously, the PL quantum yield (PLQY) is altered during noble gas ion implantation inversely correlates with the electronic stopping power of the implanted element, hence Ar implantation reduces the PLQY, while Ne even causes a PLQY enhancement. These results thus provide a guide to separate the effect of nuclear and electronic damage during ion implantation into halide perovskites.

Experimental study of single-electron detachment for Rh−, Ir− in collision with noble gases

The single electron detachment (SED) cross sections for Rh−, Ir− in collision with He, Ne, Ar, Kr, Xe in the energy range of 10 keV ≤ E ≤ 30 keV are measured by using the growth rate method. A position sensitive detector based on Multi-Channel plate (MCP) is used to measure undetached negative ions and produced neutrals. The SED cross sections increase as the incident velocity increases. These data are compared with our previous experimental data of Co− and Ir− colliding with Kr and Xe. Although the ground state electron configurations of Co−, Rh−, Ir− are all d8s2, the SED cross sections of Rh− are found to be much lower than those of Co− and Ir−.

Defect engineering-induced Seebeck coefficient and carrier concentration decoupling in CuI by noble gas ion implantation

Copper(I) iodide, CuI, is the leading p-type nontoxic and earth-abundant semiconducting material for transparent electronics and thermoelectric generators. Defects play a crucial role in determining the carrier concentration, scattering process, and, therefore, the thermoelectric performance of a material. As a result of defect engineering, the power factor of thin film CuI was increased from 332±32 to 578±58 μW m−1K−2 after implantation with noble gas ions (Ne, Ar, or Xe). The increased power factor is due to a decoupling of the Seebeck coefficient and electrical conductivity identified through a changing scattering mechanism. Ion implantation causes the abundant production of Frenkel pairs, which were found to suppress compensating donors in CuI, and this scenario was also supported by density functional theory calculations. The compensating donor suppression led to a significantly improved Hall carrier concentration, increasing from 6.5×1019±0.1×1019 to 11.5×1019±0.4×1019 cm−3. This work provides an important step forward in the development of CuI as a transparent conducting material for electronics and thermoelectric generators by introducing beneficial point defects with ion implantation.

Noble Gases in Medicine: Current Status and Future Prospects

Noble gases are a valuable but overlooked source of effective and safe therapeutics. Being monoatomic and chemically inert, they nonetheless have a surprisingly wide range of biochemical and medically valuable properties. This mini review briefly summarizes these properties for the most widely used noble gases and focuses and research gaps and missed opportunities for wider use of these intriguing ‘atomic’ drugs. The main research gaps and opportunities lie firstly in the application of advanced computational modelling methods for noble gases and recent developments in accurate predictions of protein structures from sequence (AlphaFold), and secondly in the use of very efficient and selective drug delivery technologies to improve the solubility, efficacy, and delivery of noble gases to key targets, especially for the lighter, poorly soluble gases.

Abstract B002: A therapeutically targetable positive feedback loop between long noncoding RNA-HLX-2-7, HLX, and MYC that promotes childhood cancer group 3 medulloblastoma

Abstract Medulloblastoma (MB) is the most common malignant pediatric brain tumor. MB is categorized into four main molecular subgroups: wingless pathway (WNT)-activated, sonic hedgehog pathway (SHH)-activated, group 3 (G3), and group 4 (G4). Although the driver pathways for G3 and G4 MB are unclear, most of these tumors are characterized by c-Myc and MYCN signatures, respectively. Recent studies suggest that long non-coding RNAs (lncRNAs) contribute to medulloblastoma formation and progression. We have identified lncRNA, lnc-HLX-2-7, as an oncogene and a potential therapeutic target in group 3 (G3) medulloblastomas. lnc-HLX-2-7 RNA specifically accumulates in the promoter region of its host coding gene HLX, a sense overlapping gene of lnc-HLX-2-7, which activates HLX expression by recruiting multiple factors, including enhancer elements. RNA sequencing and chromatin immunoprecipitation reveal that HLX binds to and activates the promoters of several oncogenes, including TBX2, LIN9, HOXM1, and MYC. Intravenous treatment with cerium oxide nanoparticle–coated antisense oligonucleotides targeting lnc-HLX-2-7 (CNP-ASO-lnc-HLX-2-7) and lipid nanoparticle-coated HLX (LNP-si-HLX) inhibits tumor growth by 40-50% in an intracranial medulloblastoma xenograft mouse model (p&amp;lt;0.01). Combining nanoparticle-coated lnc-HLX-2-7 and HLX with standard-of-care cisplatin further inhibits tumor growth and significantly prolongs mouse survival compared with monotherapy (p&amp;lt;0.01). Thus, the lnc-HLX-2-7–HLX–MYC axis is important for regulating G3 medulloblastoma progression, providing a strong rationale for using lnc-HLX-2-7 and HLX as therapeutic targets for G3 MBs. Citation Format: Ranjan R Perera. A therapeutically targetable positive feedback loop between long noncoding RNA-HLX-2-7, HLX, and MYC that promotes childhood cancer group 3 medulloblastoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: RNAs as Drivers, Targets, and Therapeutics in Cancer; 2024 Nov 14-17; Bellevue, Washington. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(11_Suppl):Abstract nr B002.

Fine-Tuning Microporosity of Crystalline Vanadomolybdate Frameworks for Selective Adsorptive Separation of Kr from Xe.

Selective adsorptive capture and separation of chemically inert krypton (Kr) and xenon (Xe) noble gases with very low ppmv concentrations in air and industrial off-gases constitute an important technological challenge. Here, using a synergistic combination of experiment and theory, the microporous crystalline vanadomolybdates (MoVOx) as highly selective Kr sorbents are studied in detail. By varying the Mo/V ratios, we show for the first time that their one-dimensional (1D) pores can be fine-tuned for the size-selective adsorption of Kr over the larger Xe with selectivities reaching >100. Using extensive electronic structure calculations and grand canonical Monte Carlo simulations, the competition between Kr uptake with CO2 and N2 was also investigated. As most materials reported so far are selective toward the larger, more polarizable Xe than Kr, this work constitutes an important step toward robust Kr-selective sorbent materials. This work highlights the potential use of porous crystalline transition metal oxides as energy-efficient and selective noble gas capture sorbents for industrial applications.

Bell Test of Quantum Entanglement in Attosecond Photoionization

Attosecond physics enables the study of ultrafast coherent electron dynamics in matter upon photoexcitation and photoionization, revealing spectacular effects such as hole migration and coherent Auger dynamics in molecules. In the photoionization scenario, there has been a strong focus on probing the physical manifestations of internal quantum coherence within the individual parent ion and photoelectron systems. However, quantum correlations between these two subsystems emerging from attosecond photoionization events have thus far remained much more elusive. In this work, we design theoretically and model numerically a direct probe of quantum entanglement in attosecond photoionization in the form of a Bell test. We simulate from first principles a Bell test protocol for the case of noble gas atoms photoionized by ultrashort, circularly polarized infrared laser pulses in the strong-field regime predicting robust violation of the Bell inequality. This theoretical result paves the way for the direct observation of entanglement in the context of ultrafast photoionization of many-electron systems. Our work provides a novel perspective on attosecond physics directed toward the detection of quantum correlations between systems born during attosecond photoionization and unraveling the signatures of entanglement in ultrafast coherent molecular dynamics, including in the chemical decomposition pathways of molecular ions. Published by the American Physical Society 2024

DNAR-15. GROUP 3 MEDULLOBLASTOMAS EXPLOIT A TRANSIENT MECHANISM OF TELOMERE REPAIR MEDIATED BY ZSCAN4 WHICH IS TARGETABLE FOR THERAPEUTIC BENEFIT WITH BRAIN-PENETRANT DRUGS

Abstract All cancers need some mechanism of telomere repair. However, it is unknown how Group 3 (G3) medulloblastomas (MB) repair their telomeres, even though MB is the most common malignant brain tumor in kids and G3 is its most aggressive subtype. With rare exceptions, G3 MBs lack telomerase gain-of-function alterations or evidence of constitutive alternative-lengthening-of-telomeres pathway activation. We profiled tumors from N=38 MB patients from UCSF via single-nucleus RNA sequencing; 13 cases were also subjected to single-cell assay for transposase-accessible chromatin by sequencing, and 4 were subjected to single-cell cleavage under targets and tagmentation for H3K27ac. These data identified a network of gene enhancers that were specifically active in rhombic-lip progenitor-like MB cells, the putative G3 MB cell of origin. This program was driven by zinc finger and SCAN domain containing 4 (ZSCAN4), a gene reported to drive transient telomere repair during zygotic genome activation in early embryos. CRISPR inhibition of ZSCAN4 led to significant telomere shortening, telomeric DNA damage, telomere fusions, decreased proliferation, and increased survival of orthotopic xenografts. Conversely, ZSCAN4 over-expression induced significant telomere elongation, increased proliferation, and decreased survival in vivo. Analysis of endogenous-reporter cells indicated that ZSCAN4 is transiently expressed in response to telomere shortening and increases global histone acetylation by inducing chromatin-remodeling factors. Rebastinib targeted ZSCAN4, histone acetylation, and telomere repair, was brain penetrant, and significantly enhanced orthotopic-xenograft survival with no toxicity. Acetyltransferase inhibitor CPI-1612 was brain penetrant and extended xenograft survival with no toxicity. Our data support the hypothesis that G3 MBs exploit a transient mechanism of telomere repair mediated by ZSCAN4. Targeting ZSCAN4 or downstream histone acetylation is therapeutically viable. Pan-cancer whole-genome sequencing data showed that MBs have lower telomeric content than most other cancers. Thus, MBs may be particularly vulnerable to therapeutic strategies that inhibit telomere repair.

Evaluation of H2O2, H2, and bubble temperature in the sonolysis of water and aqueous t-butanol solution under Ar: Effects of solution temperatures and inorganic additives of NaCl and KI

The yields of H2O2 and H2 formed in the sonolysis of aqueous solution under noble gas are representative indexes for understanding the chemical effects of ultrasonic cavitation bubbles. In this study, the yields of H2O2 and H2 formed under Ar were evaluated as a function of the concentration of NaCl or KI. When these yields were analyzed by using a normalization technique, it was confirmed that the yields of H2 were more clearly related to Ar solubility than those of H2O2, suggesting that H2 is a more real probe to understand the chemical effects of cavitation bubbles in water. The effects of NaCl on sonochemical formation of oxidants were also compared with those of KI. When aqueous t-butanol solution was sonicated, the yields of H2 and the maximum temperature attained in a collapsing bubble (bubble temperature) decreased with increasing solution temperature and salt concentration, suggesting that these parameters affected the quantity related to the number (and/or size) of active bubbles as well as the quality related to the bubble temperatures.

Crystallographic insights into lipid-membrane protein interactions in microbial rhodopsins.

The primary goal of our work is to provide structural insights into the influence of the hydrophobic lipid environment on the membrane proteins (MPs) structure and function. Our work will not cover the well-studied hydrophobic mismatch between the lipid bilayer and MPs. Instead, we will focus on the less-studied direct molecular interactions of lipids with the hydrophobic surfaces of MPs. To visualize the first layer of amphiphiles surrounding MPs and analyze their interaction with the proteins, we use the available highest-quality crystallographic structures of microbial rhodopsins. The results of the structure-based analysis allowed us to formulate the hypothetical concept of the role of the nearest layer of the lipids as an integral part of the MPs that are important for their structure and function. We then discuss how the lipid-MPs interaction is influenced by exogenous hydrophobic molecules, noble gases, which can compete with lipids for the surface of MPs and can be used in the systematic approach to verify the proposed concept experimentally. Finally, we raise the problems of currently available structural data that should be overcome to obtain a more profound picture of the lipid-MP interactions.

2D Nitrogen-Doped Graphene Materials for Noble Gas Separation.

Noble gases, notably xenon, play a pivotal role in diverse high-tech applications. However, manufacturing xenon is an inherently challenging task, due to its unique properties and trace abundance in the Earth's atmosphere. Consequently, there is a pressing need for the development of efficient methods for the separation of noble gases. Using mild fluorographene chemistry, nitrogen-doped graphene (GNs) materials are synthesized with abundant aromatic regions and extensive nitrogen doping within the vacancies and holes of the aromatic lattice. Due to the organized interlayer "nanochannels", nitrogen functional groups, and defects within the two-dimensional (2D)structures, GNs exhibits effective selectivity for Xe over Kr at low pressure. This enhanced selectivity is attributed to the stronger binding affinity of Xe to GN compared to Kr. The adsorption is governed by London dispersion forces, as revealed by theoretical calculations using symmetry-adapted perturbation theory (SAPT). Investigation of other GNs differing in nitrogen content, surface area, and pore sizes underscores the significance of nitrogen functional groups, defects, and interlayer nanochannels over thesurface area in achieving superior selectivity. This work offers a new perspective on the design and fabrication of functionalized graphene derivatives, exhibiting superior noble gas storage and separation activity exploitable in gas production technologies.

Ambient Synthesis of Vanadium-Based Prussian Blue Analogues Nanocubes for High-Performance and Durable Aqueous Zinc-Ion Batteries with Eutectic Electrolytes.

Prussian blue analogues (PBAs) have been widely studied in aqueous zinc-ion batteries (AZIBs) due to the characteristics of large specific surface area, open aperture, and straightforward synthesis. In this work, vanadium-based PBA nanocubes were firstly prepared using a mild in situ conversion strategy at room temperature without the protection of noble gas. Benefiting from the multiple-redox active sites of V3+/V4+, V4+/V5+, and Fe2+/Fe3+, the cathode exhibited an excellent discharge specific capacity of 200 mAh g-1 in AZIBs, which is much higher than those of other metal-based PBAs nanocubes. To further improve the long-term cycling stability of the V-PBA cathode, a high concentration water-in-salt electrolyte (4.5 M ZnSO4+3 M Zn(OTf)2), and a water-based eutectic electrolyte (5.55 M glucose+3 M Zn(OTf)2) were designed to successfully inhibit the dissolution of vanadium and improve the deposition of Zn2+ onto the zinc anode. More importantly, the assembled AZIBs maintained 55 % of their highest discharge specific capacity even after 10000 cycles at 10 A g-1 with superior rate capability. This study provides a new strategy for the preparation of pure PBA nanostructures and a new direction for enhancing the long-term cycling stability of PBA-based AZIBs at high current densities for industrialization prospects.

Tracing a Mantle Component in Both Paleo and Modern Fluids Along Seismogenic Faults of Southern Italy

AbstractAiming at understanding the source of the fluids that mineralizing within seismically active fault zones, we investigate the noble gas isotopes (i.e., helium (He), neon (Ne), and argon (Ar)) in the fluid inclusions (FIs) trapped in the calcite veins sampled along high‐angle fault zones of the Contursi hydrothermal basin, southern Italy. The latter basin lies in close vicinity of the MW = 6.9, 1980 Irpinia earthquake and exposes numerous fault scarps dissecting Mesozoic shallow‐water carbonates. The analyses of noble gases (He, Ne, Ar) are conducted to identify the origin of the volatiles circulating along the faults at the time of calcite precipitation. Then, outcomes of this discussions are compared with currently outgassing of deep‐sourced CO2 coupled to mantle‐derived He in that area, whose output is larger than those from some volcanic areas worldwide. The results indicate that He in FIs is dominated by a crustal radiogenic component (4He), and by an up to 20% of a mantle‐derived component (3He), with a highest isotopic signature of 1.38 Ra. This value is consistent with the highest percentage of mantle‐derived He associated to high‐flux CO2 gas emission in the investigated area (1.41 Ra). We propose that the variability of the He isotopic signature measured in primary FIs can result from early trapping of fluid inclusions or post trapping processes and seismic activity that modify the pristine He isotopic signature (i.e., derived from the crust and/or mantle) in groundwater along the faults during periods of background seismicity. Such investigations are fundamental to understand fluid migration in fault systems and the role of fluids in processes of earthquake nucleation.

Perovskite-structured LaFeO3 gas sensor modified by polyoxometalate electron acceptor with high sensitivity and low detection limit for acetone gas☆

Lanthanum ferrite is a representative perovskite-structured rare earth-based bimetallic oxide, which has been widely studied in magnetic materials, sensors, catalysts and batteries. Herein, we designed and prepared polyoxometalate electron acceptor decorated LaFeO3 gas-sensitive composite materials with one-dimensional nanoribbons morphology by electrospinning. The effects of different mass fraction of Keggin type phosphotungstic acid (PW12) on the gas-sensitive properties of LaFeO3 nanoribbons were investigated. The results show that the response value of LaFeO3/PW12 sensor to acetone gas first increases and then decreases with the increase of PW12 content. The LaFeO3/3%PW12 sensor exhibits a maximum response of 3.35 to 5 ppm acetone at 250 °C, a 2.6 times increase in response value and a 90 °C reduction in operating temperature compared to pure LaFeO3 nanoribbons. The LaFeO3/3%PW12 sensor exhibits good linear relation in ppb-level concentrations and the lowest detection concentration is 100 ppb. The sensors also show good repeatability in 6 tests and excellent long-term stability in 30 d. The improvement of the gas sensitive properties of the composite can be attributed to the synergistic effect between the two components. As an electron acceptor, PW12 promotes carrier migration between PW12 and LaFeO3, thereby improving the gas sensing performance of LaFeO3. This work promotes the practical application of polyoxometalate to promote rare earth-based gas sensitive materials in sensing field.

Low current iodine-fed hollow cathode discharge: insights from fluid model

Abstract As one of the fundamental components, hollow cathodes using noble gas propellant are widely used in electric thrusters. Iodine has become one of the ideal alternative propellants due to its economy and good chemical properties, while due to the complex reactions, characteristics and proper functioning of iodine-fed hollow cathodes are still unknown. Therefore, a model is needed to understand the physical-chemical process of the iodine-fed hollow cathode discharge. In this work, a self-consistent two-dimensional fluid model of the low-current iodine-fed hollow cathode discharge with detailed non-equilibrium plasma chemistry is developed and verified by the voltages of the keeper and anode obtained in the experiments. Simulations show that the electron impact ionization with iodine atoms dominates the discharge process as the density of iodine atoms is much higher than that of iodine molecules due to the electron impact dissociation and thermal dissociation. Moreover, the power balance analysis shows the heating of electrons contributed by the electric field mainly takes place near the keeper and the orifice. Ion current heating contributes significantly to the gas heating compared with the heating by the electron elastic collisions with I and I2 and the heat release or consumption during the neutral reactions. Furthermore, the influence of electronegativity on plasma characteristics is analysed. Simulations involving I− ions bring higher values of ionization degree, discharge power as well as maximum electron and gas temperatures compared with those without I−. This is similar to the differences in the plasma properties between the iodine-fed and xenon-fed hollow cathode to which the low ionization energy, large collision ionization cross-section and the electronegativity of iodine contribute together. In all, these findings can better predict the plasma behaviours in the iodine-fed hollow cathode discharge and may promote the development of the electric propulsion system using iodine propellant.

Study on hydrogen and helium chromatographic analysis system

Abstract Rare gas helium is widely used in industrial and high-tech areas, is the national important strategic resources, to lead the scientific and technological innovation has the increasingly important role, helium production capacity in China is relatively scarce, helium gas resources long-term dependence on imports. In order to strengthen the helium resource guarantee capacity of our country and ensure the advantageous position in the international development competition. In recent years, helium detection and analysis in real-time while drilling at wellsite has been gaining interest in the oil and gas industry, the detection of non-hydrocarbon gases such as helium has become the focus of current exploration. In order to meet the demand of hydrogen and helium exploration and development, a set of hydrogen-helium chromatography analyzers is developed. A separation method of helium and hydrogen combined with the pre-analysis column and the main analysis column is proposed to realize the efficient separation of hydrogen and helium, the wide spectrum TCD (Thermal Conductivity Detector) is used as the analyzer to achieve the high efficiency detection of hydrogen and helium. Field application shows that the system can detect hydrogen and helium efficiently within 30 seconds analysis cycle while drilling, which provides a technical means for the detection of hydrogen and helium in the exploration process. It provides a good technical reserve for the future large-scale development and utilization of natural hydrogen and helium.

Особенности технического регулирования технических устройств

The article examines the issues of identification of technical devices: cartridge filters of natural gas, the procedure of their compliance with current requirements of industrial safety as well as how the assessment affects the service life of a device in the future. Specific attention has been paid to two technical regulations of the Customs Union (TR TU 032/2013 and 010/2011) defined as basic documents for cartridge filters. The scope of application of technical regulations and their main provisions have been considered. The main properties of natural gas cartridge filters have been described. The fact of the production of natural gas cartridge filters by different manufacturing plants in accordance with different production standards (Technical Specifications TU 3683-001-28494535—2018 and GOST 34347—2017) and the availability of different documents confirming the compliance with safety requirements provided by technical regulations ТР ТС 032/2013 and TR TU 010/2011 is mentioned. Technical devices have been identified; as a result, it has been detected that monotypic devices may differ after the identification in accordance with TR TU: «pipelines and valves of the design pressure exceeding 0.05 MPa, nominal diameter exceeding 25 mm designed for compressed, liquefied, and dissolved under pressure gases and vapors and used for working media of group 1» or «vessels designed for compressed, liquefied, and dissolved under pressure gases and vapors used for working media of group 1» as well as «pipeline industrial valves» or «air separation and rare gas units». The impact of the results of the conformity assessment of technical devices for their service life has been analyzed. Regulatory documents establishing the requirements for the operation of technical devices have been specified. The results of the analysis have revealed significant differences within the process of registration, accounting, and commissioning of technical devices. The authors believe that the root cause of different approaches to the assessment of conformity affecting the service life of technical devices in the future is the different approaches to the development of their technical certificates.