Target Surface Research Articles

Effect of Target Surface Rotation and Jet Exit Reynolds Number on Thermal Performance in Single and Multiple Jet Impingement(s)

Effect of Target Surface Rotation and Jet Exit Reynolds Number on Thermal Performance in Single and Multiple Jet Impingement(s)

The natural product-derived JM-9 alleviates high-fat diet-induced fatty liver in mice by targeting MD2.

Metabolic dysfunction-associated steatotic liver disease (MASLD), is gradually emerging as one of the most prevalent liver diseases worldwide. Previous research demonstrated the involvement of myeloid differentiation factor 2 (MD2), a co-receptor of TLR4, as a key mediator in MASLD pathogenesis. The current study identifies JM-9 as a novel MD2 inhibitor, and focuses on evaluating its potential therapeutic effects in mitigating MASLD progression. Drug affinity responsive target stability (DARTS) assay and surface plasmon resonance assay were utilized to evaluate the MD2-targeting specificity of JM-9. In vitro, hepatocytes and macrophages were stimulated with palmitic acid (PA) followed by JM-9 treatment. In vivo, a high-fat diet (HFD)-induced MASLD model was established and subjected to JM-9 administration during the last 2months. JM-9 directly bound the Phe76 residue of MD2 to disrupt the PA-induced MD2/TLR4 complex formation, thus further restoring AMPK phosphorylation and inhibiting NF-κB activation to reducing lipid accumulation and inflammation, respectively. In the HFD-mediated MASLD mouse model, JM-9 alleviated the binding between MD2 and TLR4 in the liver and counteracted hepatic TBK1 and p65 activation and AMPK suppression, thereby mitigating liver inflammation, steatosis, and fibrosis. JM-9, as a novel MD2 inhibitor, holds potential as a viable treatment option for MASLD by playing a dual role in regulating both lipid metabolism and inflammation response.

Advanced Scattering Analysis of Targets Under Plane Waves and Electromagnetic Vortex Waves for Stealth Applications

This study investigates the scattering characteristics of typical metallic targets under the influence of electromagnetic vortex waves, with a focus on Radar Cross Section (RCS) and Orbital Angular Momentum Radar Cross Section (ORCS). Using the physical optics approximation, the induced current density on the target surface was calculated, and the backscattered field was derived. The comparative analysis highlights the advantages of electromagnetic vortex waves over plane waves in stealth applications, with an in-depth examination of the impact of different OAM modes on power distribution and flat plate scattering characteristics. The unique properties of electromagnetic vortex waves show promising applications in stealth radar and target detection. Furthermore, the study discusses the potential for using OAM waves in enhancing radar system performance, target identification, and electronic countermeasures. The ability of OAM waves to provide selective detection capabilities and reduce RCS under certain conditions makes them particularly valuable for military stealth applications. The combination of MIMO technology with OAM waves is also explored as a means to further improve detection capabilities and flexibility. The findings suggest that electromagnetic vortex waves have a broad range of applications beyond stealth, including radar sensing, imaging, and rotational Doppler detection, thereby opening new avenues for advanced radar technologies

Theoretical Study of the Pre-Plasma Density Scale Length’s Influence on the Absorption Efficiency in Laser–Solid Interaction at Relativistic Laser Intensities for PW-Class Lasers

This work studied the pre-plasma that builds up in interactions of focused high-power PW-class lasers with solid targets at the target surface facing the laser beam, and its impact on the global laser absorption efficiency as well as on the spectral cut-off energy of laser-generated proton beams. Our practical heuristic estimates were derived from the example of the VEGA-3 laser at CLPU. Our modeling results for the pre-plasma expansion due to the laser pedestal of VEGA-3 were benchmarked by hydrodynamic simulations, revealing good agreement for the evolution before the arrival of the main Gaussian laser intensity peak. Our detailed numerical two-dimensional Particle-in-Cell simulations showed the impact of different pre-plasma scale lengths on the absorption efficiency of laser energy into electrons, relevant for the seeding of other types of radiation. It was shown that the absorption can increase manyfold when increasing the pre-plasma scale length. This effect can be beneficial for the spectral cut-off energy of accelerated protons, where a trade-off between absorption and electron dynamics yields an optimum pre-plasma scale length. The findings can be applied to other PW-class laser facilities.

Could adjuvants serve as an agroecological tool?

Adjuvants are agrochemicals or natural substances, commonly mixed with pesticides to increase their efficacy or reduce off-target movement by modifying the physical properties of the spray solution, such as surface tension, droplet size, and spreadability, which ultimately improve pesticide adhesion and coverage on target surfaces. Adjuvant use across Europe remains less widespread compared to regions like the USA, where adjuvants are often recommended or required with certain herbicide applications. This paper highlights the potential benefits of incorporating adjuvants with herbicides in weed control, particularly as a strategy to reduce overall herbicide use. Findings from dose-response research on available adjuvants suggest they may enable the application of lower herbicide rates than typically recommended, without sacrificing effectiveness, thereby contributing to the goal of reducing herbicide use by 50% by 2030 in Europe. Furthermore, literature findings indicate that adjuvants significantly improve weed control by enhancing the performance of active ingredients, with efficacy increases of up to 50% compared to using herbicides alone. The integration of adjuvants into herbicide tank mixtures offers considerable promise, especially for managing herbicide-resistant weeds and achieving effective weed control.

Laser driven electron acceleration from dual-plane composited targets for space radiation applications

Laser driven electron beam has important application value in the field of space radiation environment simulation. However, due to the shortcomings of poor spectrum tunability and high laser energy of the electron beam generated by laser direct irradiation of high-density solid targets, which limits to its wide application. In this paper, a scheme is proposed to simulate the orbital electron radiation in near-Earth space by using laser driven dual-plane composited target electron acceleration. It is found that the high-density solid target Ⅱ can provide a large number of low energy electrons, while the vertical plane target Ⅰ placed in the front surface of target II can provide a small number of high energy electrons, which makes the electron energy spectrum very close to that of the space radiation environment. In order to evaluate the similarity between the generated energy spectrum and the space radiation spectrum, an evaluation method for the similarity of energy spectra is proposed, which can describe the local and global similarity of the energy spectra. For vertical plane target Ⅰ with low density, the electron acceleration is dominated by the laser ponderomotive acceleration that generates a half-wavelength oscillation. As the density increases, the electron acceleration gradually transitions from the laser ponderomotive acceleration to the surface ponderomotive acceleration, and the electron beam energy spectrum is modulated effectively. Meanwhile, there is a linear relationship between the electron temperature of the generated electron beam and the length and density of the target Ⅰ, and the optimal target parameters are obtained by the Bayesian optimization, and the generated electron beam is much better matched to the space radiation environment. Compared with the laser driven single-plane target electron acceleration, the proposed scheme has better tunability of energy spectrum and lower requirement of laser intensity. The results provide a theoretical reference for the experimental study to simulate space radiation environments in different orbital by using laser-driven electron beams.

Design of compliant thermal actuators using topology optimization involving design-dependent convection and pressure load

This study presents a topology optimization method for thermal actuators that accounts for boundary conditions influenced by variables such as thermal convection and pressure load. Thermal actuators with gripper-like designs are essential for handling hot and brittle materials. The objective of this study is to design actuator shapes that achieve an optimal balance between flexibility and stiffness in high-temperature environments. Unlike previous studies that consider load conditions imposed on fixed boundaries within the design domain, this research introduces a high-temperature fluid as the driving source and employs a novel approach to boundary condition setting by integrating fictitious physical problems. This approach allows for the precise specification of various boundary conditions across multiple domains. A weighted-sum method is applied to optimize three objective functions related to deformability, stiffness, and thermal diffusibility of the actuators. To address the issue of excessively thin structures compromising deformability and the poor convergence of the optimization process, stress constraints based on the optimization history are introduced. The proposed method is validated through numerical examples, demonstrating improvements in structural deformability while controlling deformation on the target surface plane. The numerical results confirm that the objective function decreases and stress is suppressed, verifying the effectiveness of the proposed approach.

Multi-Step Simulations of Ionized Metal Physical Vapor Deposition to Enhance the Plasma Formation Uniformity

Ionized metal physical vapor deposition (IMPVD), which is operated at a very low pressure to take advantage of the metal sputtering effect on the target surface, has unique properties compared with conventional DC magnetron sputtering. In this study, we investigated the effect of the rotating magnetic field on the plasma formation of IMPVD to enhance the deposition uniformity. This was accomplished through a multi-step simulation, which enabled plasma analysis, sputtered particle and chemical reaction analysis, and deposition profile analysis. A two-dimensional particle-in-cell Monte Carlo simulation utilizes the exact cross-section data of the Cu ion collisions and calculates the particle trajectories under specific magnetic field profiles. This new methodology gives guidance for the design of the magnetic field profiles of IMPVD and an understanding of the physical mechanism.

Circulating microRNAs as a Prognostic Tool to Determine Treatment Efficacy in Lung Cancer Patients Undergoing Pembrolizumab PD-1 Blockade Immunotherapy.

Background: Pembrolizumab has recently emerged as a PD-1 blockade immunotherapy treatment for lung cancer. It is critical that such treatment strategies for lung cancer should be chosen not only on the basis of histopathological features and the expression of targetable cell surface proteins (such as PD-1), but should rather be selected based on other determinants of treatment success or risk factors for poor prognosis. One method to forecast cancer trajectory is the identification of biomolecular signatures such as microRNAs (miRNAs), non-protein-coding RNA molecules that play a regulatory role in gene expression by modulating the translation or stability of messenger RNA. Methods: To find out which miRNAs have an important influence on anti-PD-1 treatment outcomes, we evaluated miRNA levels in sera from 38 lung cancer patients undergoing 3 months of pembrolizumab treatment. We selected a panel of miRNAs previously shown to be involved in lung cancer or PD-1 signaling and performed qPCR analysis. Results: Overall, we observed a significant decrease in the levels of miR126-5p (4-fold), let-7a (5-fold), miR133a-3p (4-fold), miR3615 (2-fold), miR4516 (3-fold), miR16 (3-fold), miR34c-5p (2-fold), miR20b-5p (5-fold), miR106b-5p (5-fold), miR146a-5p (3-fold) and miR181b-5p (3-fold) in response to treatment indicating effectiveness of immunotherapy. Within our selected panel of miRNAs, we identified two markers relevant to cancer prognosis: miR-217, which is negatively associated with patient survival, and let-7a, which is positively associated with patient survival. Conclusions: Our findings suggest that circulating miRNAs can be used for future treatment evaluation and lung cancer prognosis, with potential as therapeutic targets.

Multi-Channel Fusion Decision-Making Online Detection Network for Surface Defects in Automotive Pipelines Based on Transfer Learning VGG16 Network.

Although approaches for the online surface detection of automotive pipelines exist, low defect area rates, small-sample and long-tailed data, and the difficulty of detection due to the variable morphology of defects are three major problems faced when using such methods. In order to solve these problems, this study combines traditional visual detection methods and deep neural network technology to propose a transfer learning multi-channel fusion decision network without significantly increasing the number of network layers or the structural complexity. Each channel of the network is designed according to the characteristics of different types of defects. Dynamic weights are assigned to achieve decision-level fusion through the use of a matrix of indicators to evaluate the performance of each channel's recognition ability. In order to improve the detection efficiency and reduce the amount of data transmission and processing, an improved ROI detection algorithm for surface defects is proposed. It can enable the rapid screening of target surfaces for the high-quality and rapid acquisition of surface defect images. On an automotive pipeline surface defect dataset, the detection accuracy of the multi-channel fusion decision network with transfer learning was 97.78% and its detection speed was 153.8 FPS. The experimental results indicate that the multi-channel fusion decision network could simultaneously take into account the needs for real-time detection and accuracy, synthesize the advantages of different network structures, and avoid the limitations of single-channel networks.

In situ calorimetric temperature measurements of Cu, Cr, Ti targets during DC magnetron sputtering

Direct measurements of the temperature of Cu, Ti, and Cr targets (3 mm thick, Ø 55 mm) using thermocouples attached to the front (erosion zone) and back sides of the targets during magnetron sputtering (DC) were performed. The variables are the target mode (cooled or uncooled target), working gas (Ar, N2), and discharge power density (qin). It was shown that the target temperature reaches ∼730 K on the front and ∼530 K on the back sides of the cooled target, while for an uncooled one, it is ∼1050 and 950 K, respectively (Cu target). For both modes and all targets, the target temperature is slightly higher when sputtering in N2. Calculations of the surface temperature based on measurements of the target temperature and its emissivity showed that for all targets, their surface temperature is significantly higher compared to the bulk of the target. Based on the temperature measurements on opposite sides of the Cu target, its dynamic thermal conductivity is calculated. It turned out that it is ∼100 times lower than the thermal conductivity of normal Cu. The above results are discussed based on a physical model that assumes the appearance and existence during sputtering on the target surface of a layer whose properties strongly differ from those of ordinary metals.

Simulations of divertor designs that spatially separate power and particle exhaust using mid-leg divertor particle pumping

Predictive design modeling of a Dissipation-Focused Divertor for future operation in DIII-D reveals that increasing the poloidal distance of the pump duct entrance from the target surface along the low-field side divertor baffle increases neutral compression and modifies the spatial distribution of power dissipation. With a divertor pump located mid-leg between the target and the X-point, SOLPS-ITER boundary plasma simulations without drifts predict the formation of a dense neutral cloud near the target with > 30x higher neutral compression in detachment, a more stable detachment front located further from the target, and ∼ 25 % lower outer midplane separatrix density required for detachment onset, compared to a pump located in the scrape-off layer at the target surface. Up to 19 MW of power flowing into the divertors is modeled using the following two numerical implementations for particle pumping: a specified fraction of particles incident on variable wall sections of the plasma grid is removed from the computational domain (so-called albedo pumping), and a pump duct is modeled which includes dynamics of kinetic neutrals in the duct. The simulations show that the detachment front is located between the divertor target and the X-point and is relatively stable near the pump entrance, without a strong dependence on gas puff rate or injected power. The mid-leg pump design spatially separates the two primary functions of a divertor (power handling and particle exhaust), with the majority of power dissipation occurring near the target plate and particle exhaust taking place further upstream. The benefit of enhanced dissipation using mid-leg pumping comes at the cost of a higher outer midplane separatrix density for a given amount of particle injection.

Assessment of multifunctional activity of graphene oxide and guar gum-based nanomaterials against Aedes aegypti

Nanomaterials have been receiving much research attention in controlling insect pests and vectors. Properties, such as small surface-to-volume ratio, low dosages, durability, solubility, enhanced target activity, pore size and surface characteristics have enabled the design of precise and targeted insecticides through adsorption, encapsulation, and conjugation. The reported study aims to evaluate the efficacy of graphene oxide (GO) and guar gum (GG)-based nanomaterials against early fourth instar of Aedes aegypti, a mosquito responsible for transmitting diseases like dengue fever, Zika virus, and chikungunya, among many others. GO and a total of eight nanomaterials (SA-1 to SA-8) were formulated using GO, GG and their combinations with ferrous oxide and copper oxide. Each material was characterized using various biophysical techniques. The materials were evaluated for larvicidal potential by assessing their efficacy on the survival and morphology of Ae. aegypti, while the contact irritancy activity focused on determining their irritant properties upon direct exposure to the female adults. The larvicidal and irritant bioassays, conducted with these nanomaterials at different concentrations, demonstrated concentration-dependent mortality and significant behavioral responses. The exposures with nanomaterials also resulted in a deposition of black soot on the larval cuticle. The most effective nanomaterial was found as ferrous oxide nanomaterial which induced 100% larval mortality as well as significant contact irritancy. The results indicate the potential use of GO and GG-based nanomaterials against Ae. aegypti after concentration optimization.

Morphological Characterization and Optical Properties of CIGS/TiO2 Thin Films Using Sputtering Technique

Solar energy as a renewable energy source, is currently an important alternative to meet energy needs because of its unlimited amount and environmentally friendly. Almost the entire surface of the earth receives sunlight optimally, so breakthroughs are needed to transform the solar energy into electricity. In the research development process that was to develop advanced materials to support the development of alternative energy. Thin film synthesis was carried out using the Physical Vapor Deposition (PVD) of Direct Current (DC) Sputtering method on Indium Tin Oxide (ITO) substrates using Copper Indium Gallium Selenide (CIGS) and TiO2 with deposition time variations of 30, 45, and 60 minutes. Based on the test results, thin film surface with the largest grain size is 266.75 nm at CIGS/TiO2 45 minutes. This shows that more CIGS and TiO2 atoms are released from the target surface, forming clumps that cover the substrate surface along with the addition of deposition time. The longer the deposition time shows the higher the absorbance value. The highest absorbance value is 4.60873, which was achieved by 60 minutes CIGS/TiO2 sample with wavelength of 271 nm.

Influence of hydrogen content in tokamak scrape-off-layer on performance of lithium divertor

Abstract Self-replenishing liquid metal coatings are considered as a perspective divertor design able to withstand challenging particle and power loads of a fusion tokamak-reactor. Numerical modeling of the scrape-of-layer (SOL) plasma with advanced 2D codes, such as SOLPS, is necessary for developing of the ‘liquid-metal’ divertor. In this work we report on upgraded version of SOLPS 4.3 code liquid metal erosion module implemented earlier in our group and present results of simulations of T-15MD tokamak with Li-covered divertor plates. The erosion model includes all main processes Li erosion, i.e. physical sputtering, thermal sputtering, evaporation, and prompt redeposition. Unlike some other available implementations, Li atoms are considered in kinetic approximation in our version. A detailed analysis of Li erosion and flow in T-15MD configuration for various powers (6–12 MW) and H content in the SOL is presented. It is shown that the most of eroded Li particles are redeposited on the divertor targets, however, in some regimes absolute Li flow from the divertor is still large and might lead to significant main plasma dilution with Li. Vapor shielding effect is pronounced on both divertor targets in the most reasonable regimes providing low peak heat flux values at the target plates, less than 10 MW m−2. The target erosion rate and surface temperatures are within limits of the most target designs. Moreover, in strongly shielded cases the target temperature can be even lower than the Li melting temperature meaning that external heating is required to keep Li flowing. Sensitivity analysis shows that our results are most sensitive to the target heat conduction parameters, i.e. the target thickness, outer surface temperature. It means that controlling the target cooling rate can be a useful tool for controlling the liquid Li divertor regime. Variation of the Li erosion rate parameters has little effect on the divertor performance.

2-Hydroxyisobutyric acid targeted binding to MT-ND3 boosts mitochondrial respiratory chain homeostasis in hippocampus to rescue diabetic cognitive impairment

BackgroundThe prevalence of diabetic cognitive impairment (DCI) is significant, some studies have shown that it is related to mitochondrial respiratory chain homeostasis, but the specific mechanism is not clear. 2-hydroxyisobutyric acid (2-HIBA) is a novel short-chain fatty acid with potential applications in the treatment of metabolic diseases because it can regulate mitochondrial disorders. Our aim was to explore a novel mechanism of action for 2-HIBA in the treatment of DCI in mitochondrial respiratory chain homeostasis. MethodsMetabolic substances and differentially active metabolic pathways in the serum of diseased mice were identified based on multi-omics analysis. The nanoLC-Obitrap-MS technology was utilized to detect the content of selected small molecules with differential metabolic activity in the hippocampus and mitochondria of mice to evaluate their permeability through the blood-brain barrier (BBB) and outer mitochondrial membrane. A combination of behavioral, proteomic, and molecular biology approaches was used to explore specific regulatory mechanisms and identify potential pharmacological targets. Additionally, using techniques such as protein thermal shift, drug affinity responsive target stability (DARTS), hydrolase stability, and surface plasmon resonance (SPR) experiments, we demonstrated the direct binding effects of small molecule metabolites with protein targets. Results2-HIBA was found to directly ameliorate cognitive dysfunction in db/db mice by penetrating the blood-brain barrier and reversing the decrease in the protein content of NADH dehydrogenase 3 (MT-ND3) in the hippocampus through direct binding to ND3. This action helps maintain the stability of NAD+/NADH and regulate the mitochondrial respiratory chain balance. Furthermore, a combined medication plant agonist of 2-HIBA can enhance the expression of MT-ND3, thereby improving cognitive dysfunction in mice. ConclusionMT-ND3 is a crucial target for improving diabetic cognitive dysfunction, and 2-HIBA can directly bind to the MT-ND3 protein to alleviate the functional impairment of the mitochondrial respiratory chain in mice to treat DCI.

Shannon Entropy Characterization of High-Entropy Thin Films Synthesized by Pulsed Magnetron Sputtering: The Influence of Modulation Frequency

This manuscript presents a comprehensive study of the synthesis of high-entropy TiCrFeCoNi alloy (HEA) thin films via pulsed magnetron sputtering (PMS).The research investigates the impact of various modulation frequencies on the material properties of the synthesized films. By employing Shannon entropy as a novel method to characterize the complexity and homogeneity of high-entropy thin films, we offer new insights into the synthesis process under various thermodynamic conditions. The initial characterization of the alloy, using calculated parameters such as mixing entropy, enthalpy of mixing, and others, sets the stage for a deeper understanding of the alloy's formation and stability. The experimental methodology encompasses target synthesis, sputtering system setup, sample synthesis, and comprehensive process and sample characterization, including EDS analysis, surface and cross-sectional analyses using SEM, and mechanical property assessments via nanoindentation. Results indicate that modulation frequency significantly influences the plasma discharge process, and consequently, the composition, microstructure, and mechanical properties of the HEA films. EDS analysis confirms the successful synthesis of the target alloy composition, and surface and cross-sectional analyses reveal the effects of modulation frequency on film morphology and structure. Mechanical property measurements highlight the variations in hardness and Young’s modulus among the synthesized films. The study elucidates the role of PMS parameters, especially modulation frequency, in controlling the synthesis of high-entropy thin films, paving the way for optimizing film properties for advanced material applications.Graphical

Machine learning‐based screening of pesticide adjuvants for reduction of pesticide losses on wheat leaf surfaces

AbstractUsing pesticide spray adjuvants to improve the physicochemical properties of pesticide liquids can effectively increase droplet deposition on target surfaces. However, there are no clear guidelines for the selection among complex and diverse adjuvants. We aimed to build a model for screening pesticide adjuvants through machine learning. In this paper, five machine learning classification models (decision tree, support vector machine, random forest, logistic regression, and naive Bayes) were developed to predict droplet deposition performance on the superhydrophobic plant leaf surfaces based on the physicochemical properties of pesticide liquids. Among these models, decision tree, support vector machine, and random forest exhibited superior performance. Significance analysis showed that adhesion, equilibrium surface tension, and contact angle are critical factors influencing droplet deposition on wheat leaves. Notably, the decision tree model, due to its simplicity and intuitiveness, is particularly suitable for field applications. Our findings provide a platform for the rapid and accurate screening of pesticide spray adjuvants by simply measuring the physicochemical properties of pesticide droplets.

Numerical investigation on dimpled target average heat transfer in free-surface water jet impingement and its enhancement effect versus flat plate target

Jet impingement serves as an effective method to enhance heat transfer in diverse industrial applications, utilizing either a separate fluid from the ambient (free-surface jet) or identical fluids (submerged jet). The target surface undergoes distinct thermal processes, featuring zones like the stagnation zone, boundary layer formation, and the transition from laminar to turbulent wall flow. However, heat transfer efficiency diminishes significantly due to pressure gradient changes beyond the stagnation zone, impeding flow and boundary layer development. Addressing this decline through surface modification techniques, such as incorporating spherical dimples, emerges as an innovative approach. This study develops a numerical model via Computational Fluid Dynamics (CFD) simulations utilizing Volume of Fluid (VOF) modeling for water jet impingement on a flat plate target. The model’s validity is established by comparing hydrodynamic and thermal aspects in both laminar and turbulent scenarios against established experimental data in literature. Nine dimpled target surfaces, featuring diverse dimensional properties and positioning configurations, are examined using this model to explore potential enhancements in heat transfer intensity. The findings indicate a notable increase in the overall surface average Nusselt number, potentially reaching up to 50% by implementing dimples in the current context. Moreover, the study highlights that the radial distribution of dimples and the non-uniform flow path ahead of the incoming fluid, which differs from parallel flat flow, result in varying effects based on dimensional properties. For instance, it has been found that modifying dimensions such as deepening dimples or altering their proximity could yield contrary effects, emphasizing the need for an optimization methodology to determine the most efficient dimpled surface setup within a given geometry.

High Sensitivity of Energy Dispersive X-Ray Spectroscopy Measurement Using Liquid Cell with Electron Transmittance Window Ultra-Thinned by a Gas Cluster Ion Beam

In recent years, enclosing liquid in a “liquid cell” (Fig. 1) has made it possible to analyze the chemical composition of the liquid sample and map samples in the liquid-solid interface using XPS, EDX, SEM in ultra-high vacuum (UHV). The most important part of the cell is the electron transmission window that allows electrons to input to or extract from the liquid sample. Silicon nitride (SiNx) is the most suitable material as the window, which has excellent mechanical properties. R. Endo et. al. has successfully measured the concentration of CsCl solution using a SiNx window with the film thickness of 5 nm1. However, the transmittance of 1 keV photoelectron is about 10% with the thickness of SiNx membrane. When the membrane thickness is decreased to 2 nm, the transmittance can be improved to more than 40%, which means that even higher sensitivity can be achieved. However, the burst pressure must be 1 atm or more because the membrane needs to perform enclosing a liquid sample in UHV. In previous research, we demonstrated low damage etching of an SiNx film using gas cluster ion beam (GCIB) for thinning the window2. Herein, GCIB is composed of aggregates of several thousands of atoms, and the energy of the individual atoms in the GCIB reduces to several eV/atom with an acceleration voltage of several kV. This enables irradiation on the target surface with little damage. Combining O2-GCIB irradiation and exposure of acetylacetone (Hacac) gas enable reactive etching of SiNx2.In this study, we utilized the above techniques to ultra-thin SiNx films and investigate whether the low-damage irradiation effect of GCIB is effective for SiNx films. In addition, Proof-of-principle of high sensitivity in liquid sample detection using ultra-thinning SiNx films is demonstrated using SEM/EDS.We have evaluated the burst pressure of ultra-thinned SiNx membranes of TEM window chips (SiMPore, Inc.) by reactive etching with O2-GCIB and Hacac gas, where the thickness was originally 11 nm. The SiNx membrane was also etched in the same way using 400 eV Ar+ beam, and the burst pressure was evaluated. These irradiation doses were controlled so that the remaining SiNx membrane thickness was 4.5 nm. As a result, the burst pressure was 1 atm in the case of Ar+ beam, whereas it was 2.5 atm in the case of the GCIB etching. Therefore, it was found that low damage irradiation of GCIB was valid for thinning SiNx membrane.We sealed pure water in the liquid cell shown in Fig. 1 and performed EDS measurement. When electron beam with the energy of 5 keV was injected at the SiNx/water, generated characteristics X-ray of oxygen which photon energy is 0.52 keV could be observed. On the other hands, no O peak was observed in the SiNx/Si region. This result indicates that the O peak originated from the pure water under the SiNx membrane. Next, we carried out the measurements on a pristine SiNx membrane (t = 11 nm) and the GCIB-etched SiNx membrane (t = 4.5 nm), and compared their O peak characteristic X-ray intensities. Herein, the incident electron energies were 1.0 and 1.5 keV. The peak intensity of the GCIB-etched SiNx membrane was 1.6 times stronger than that of the pristine membrane at 1.5 keV. At 1.0 keV, the O peak was observed in GCIB-etched SiNx, but not in pristine SiNx. This is because the penetration depth of electrons in the SiNx film decreases with decreasing electron energy. From the above results, we have shown that the ultrathin SiNx membrane thinned by GCIB could be used for highly sensitive detection of pure water. Acknowledgement This work was supported by JSPS KAKENHI Grant Numbers 23K13236 and 22K04930.