bluuebunny/crossref_metadata_2025 huggingface dataset:
Axisymmetrical FEM Analysis of Adhesive Butt Joint of Finite Circular Pipe Subjected to Internal Pressure
Authors: Katsuo Masahide , Sawa Toshiyuki , Nakagawa Fumito
Published: September 2024

The stress distributions and strength of adhesive butt joints of pipes of which the both ends are closed are analyzed by using an axisymmetric finite element method (FEM). The interface stress distributions are demonstrated. The joint strength is estimated using the interface stress distribution. The butt adhesive joints with small flanges and without flanges were manufactured. Rupture tests of the adhesive butt joints of pipes subjected to internal pressure by hydraulic pump were carried out. In addition, rupture tests of the joints were also conducted by using a material testing machine. Strain measurements were carried out on the joints. It is found that the stress singularity occurs at the inner and the outer edges of the interfaces. It is seen that the stress singularity is larger at the inner edge than that at the outer edge. The strength of the joints is evaluated using 95% non-rupture probability of the rupture test results. As a result, it is found that the strength of the joints with flanges are larger than that without flanges. Furthermore, it is observed that the strength of the joints with flanges is not proportional to the bonded area of the joints. The estimated values of the joint strength are in fairly good agreement with the experimental results.
A Two-Dimensional Finite Element Thermal Stress Analysis of Butt Adhesive Joints Containing Some Hole Defects
Authors: Nakagawa Fumito , Sawa Toshiyuki , Nakano Yuichi , Katsuo Masahide
Published: September 2024

Thermal stress distributions in butt adhesive joints containing some hole defects under uniform temperature changes were analyzed by using a two-dimensional finite element method (FEM). Thermal stresses in the joints which contained no holes, 3-hole, 8-hole and 16-hole defects in an adhesive layer were studied. Especially, the stress concentrations around the hole defects and near the edge of the interface between the adherends and an adhesive were examined. From the results, the thermal stresses around the hole defects located near the center portion of the adhesive layer were found to be larger than those of the hole defects located near the free surface of the adhesive layer. The thermal stress distributions near the edge of the interface decreased with an increase of the amount of holes and a decrease of the Young’s modulus of the adhesive layer. For verification, a photoelastic experiment was carried out. Fairly good agreement was seen between the numerical and the experimental results.
Axisymmetric Stress Analysis of Bonded Shrink Fitted Joints Subjected to Torsional Loads
Authors: Yoneno Masahiro , Sawa Toshiyuki , Motegi Youichi
Published: September 2024

This paper deals with stress analysis and strength evaluation of bonded shrink fitted joints subjected to torsion. The stress distributions in the adhesive layer of bonded shrink fitted joints are analyzed by using the axisymmetric theory of elasticity when an external torsion is applied to the upper end of shaft. The effect of the outer diameter and the stiffness of rings on the interface stress distributions are clarified by the numerical calculations. Using the interface stress distributions, joint strength is predicted. In addition, joint strength was measured experimentally. It is seen that a rupture of adhesive layer is initiated from the upper edge of the interfaces when a torsion is applied to the upper end of shaft. The numerical result are in fairly good agreement with the experimental results. It is found that the joint strength of bonded shrink fitted joints is greater than that of shrink fitted joints.
Experimental Investigation on Bolt Load Reduction in Bolted Joints
Authors: Kumakura Susumu , Kuramoto Hiroyuki , Nishiyama Toshio , Kobayashi Takashi
Published: September 2024

Bolted joints are widely used in mechanical structures. They are very useful because they can be disassembled when necessary. However, in practice, accidents have happened due to thread loosening and relaxation of bolted joints. In designing bolted joints, it is necessary to prevent thread loosening and reduction of axial bolt load of bolted joints. Loosening is due to bolt-nut rotation and the reduction of bolt load due to permanent setting or imbedding. In the guideline VDI2230 for design of bolted joints, data for estimating the reduction of bolt load is described, where the amount of permanent setting is proportional to the ratio of grip length to the nominal diameter of bolts. However, the theoretical or experimental grounds are not known. For reliable design of bolted joints, it is necessary to investigate the loosening of bolt load in bolted joints and to establish a method for estimating the amount of reduction in bolt load.

The objective of this paper is to measure the permanent set and reduction of bolt load in bolted joints subjected to repeated axial loads. The effects of grip length and the material of clamped parts on the permanent set are examined experimentally. The results obtained are as follows.

(1) The reduction of bolt load is decreased regardless of the material of clamped parts as the grip length increases.

(2) The amount of permanent set is decreased as the grip length increases.

(3) The results obtained by the experiments contradict the results described in VDI2230.
On the Stress Concentration in the Axially Loaded Bolts for Some Threaded Joints
Authors: Cretu Augustin , Lazar Ioan
Published: September 2024

This study started from the results of the tests performed on plane and three-dimensional photoelastic models of some axially loaded bolts — examined in monochromatic polarized light (Na) — to which it was modified, step by step, the height of the bolt head, the diameter of the head, as well as the dimensions and the position of the hexagonal key hole. With these models, we studied the stress distribution and the stress concentration — using both photoelastic method and boundary element method (BEM) — in three characteristic points: A — at the top of the bolt head, on the symmetry axis; B and C on the groove between bolt shank and bolt head.

A new series of tests were done on a group of plane models for which the variable parameters were the distance between the end fillet of the thread and the bolt head (10p, 5p, 2p and 0p, where p is the pitch) and the value of the radius of the groove between bolt shank and bolt head (r = 3; 2; 1; 0.8; 0.2 and 0.0 mm).

The examination of the isochromatic fringes for these photoelastic models leads to the conclusion that the density of isochromatic fringes rises with the decrease of the groove radius and with the decrease of the distance between the end fillet of the thread and the bolt head.

The use of the BEM to study the stress distribution in the same photoelastic models leads to the table systematization of the numerical results and to the chart representation of the following stresses:

- the maximum equivalent stress (von Mises) on the groove between bolt shank and bolt head varying with the value of the groove radius and with the distance between the end fillet of the thread and the bolt head;

- the maximum normal stress on the thread base of the end fillet of the thread, towards the bolt head, varying with the distance between the end fillet of the thread and the head, corresponding to various values of the groove radius.

Highlighting the extreme values of the stress in the stress concentration zones of some threaded joints and the determination of the stress concentration factors allow a general vision on the state of stress in the analyzed machine elements. This allows, starting from the obtained results, to estimate the behavior of similar machine elements under load and to make geometrical and technological optimization of these types of machine elements.
Estrogen signaling suppresses tumor-associated tissue eosinophilia to promote breast tumor growth
Authors: Artham Sandeep , Juras Patrick K. , Goyal Aditi , Chakraborty Prabuddha , Byemerwa Jovita , Liu Siyao , Wardell Suzanne E. , Chakraborty Binita , Crowder Daniel , Lim Felicia , Strawser Corinne H. , Newlin Madeline , Racioppi Alessandro , Dent Susan , Mirminachi Babak , Roper Jatin , Perou Charles M. , Chang Ching-Yi , McDonnell Donald P.
Published: September 2024

Estrogens regulate eosinophilia in asthma and other inflammatory diseases. Further, peripheral eosinophilia and tumor-associated tissue eosinophilia (TATE) predicts a better response to immune checkpoint blockade (ICB) in breast cancer. However, how and if estrogens affect eosinophil biology in tumors and how this influences ICB efficacy has not been determined. Here, we report that estrogens decrease the number of peripheral eosinophils and TATE, and this contributes to increased tumor growth in validated murine models of breast cancer and melanoma. Moreover, estrogen signaling in healthy female mice also suppressed peripheral eosinophil prevalence by decreasing the proliferation and survival of maturing eosinophils. Inhibiting estrogen receptor (ER) signaling decreased tumor growth in an eosinophil-dependent manner. Further, the efficacy of ICBs was increased when administered in combination with anti-estrogens. These findings highlight the importance of ER signaling as a regulator of eosinophil biology and TATE and highlight the potential near-term clinical application of ER modulators to increase ICB efficacy in multiple tumor types.
Systemic dysregulation and molecular insights into poor influenza vaccine response in the aging population
Authors: Kumar Saumya , Zoodsma Martijn , Nguyen Nhan , Pedroso Rodrigo , Trittel Stephanie , Riese Peggy , Botey-Bataller Javier , Zhou Liang , Alaswad Ahmed , Arshad Haroon , Netea Mihai G. , Xu Cheng-Jian , Pessler Frank , Guzmán Carlos A. , Graca Luis , Li Yang
Published: September 2024

Vaccination-induced protection against influenza is greatly diminished and increasingly heterogeneous with age. We investigated longitudinally (up to five time points) a cohort of 234 vaccinated >65-year-old vaccinees with adjuvanted vaccine FluAd across two independent seasons. System-level analyses of multiomics datasets measuring six modalities and serological data revealed that poor responders lacked time-dependent changes in response to vaccination as observed in responders, suggestive of systemic dysregulation in poor responders. Multiomics integration revealed key molecules and their likely role in vaccination response. High prevaccination plasma interleukin-15 (IL-15) concentrations negatively associated with antibody production, further supported by experimental validation in mice revealing an IL-15–driven natural killer cell axis explaining the suppressive role in vaccine-induced antibody production as observed in poor responders. We propose a subset of long-chain fatty acids as modulators of persistent inflammation in poor responders. Our findings provide a potential link between low-grade chronic inflammation and poor vaccination response and open avenues for possible pharmacological interventions to enhance vaccine responses.
Complete genome and plasmid sequences of
Moraxella
sp. strains K02 and K23, closely related to
M. osloensis
, isolated from freshwaters
Authors: Wakabayashi Ryoka , Naganuma Takeshi , Nakai Ryosuke
Published: September 2024

Moraxella osloensis
is a cosmopolitan bacterium, ranging from human body to diverse environments. Only 2 of the 11 complete genomes so far are from non-clinical strains. Here, we present the complete genome and plasmid sequences of two freshwater isolates. The data will provide insights into the cosmopolitanism of this species.
Circularly assembled genome sequences of
Asticcacaulis
sp. strain MM231 and
Brevundimonas subvibrioides
MM232, isolated from a pond at Bielefeld University campus
Authors: Laker Bianca , Schulze Tim , Reis Mara , Bormann Sophia-Maria , Radke Gianluca , Klages Levin Joe , Busche Tobias , Wobbe Lutz , Bräutigam Andrea , Eisenhut Marion
Published: September 2024

Photosynthetic organisms often interact with heterotrophic microbes. We here report the complete genome sequences of the bacterial strains
Asticcacaulis
sp. MM231 and
Brevundimonas subvibrioides
MM232. Both bacteria were co-isolated from a single green colony originating from an aquatic sample taken from a pond at the Bielefeld University campus.
Effects of mycotoxin-producing fungi on the fitness and gut bacterial community of the soil springtail
Folsomia candida
Authors: Xu Yang , Tang Lingxiao , Xie Zhen , Duan Xingwei , Wang Kaisha , Zhu Jialin , Huang Yangyang , Yang Kailang , Xu Lei , He Hong
Published: September 2024

Mycotoxin-producing fungi are widespread and their adverse effects on mammals have been investigated; however, their impacts on soil invertebrates are not fully understood.
Folsomia candida
is a model soil arthropod that represents an important part of the soil invertebrate community. This study investigated the consequences of
F. candida
grazing on mycotoxin-producing fungi
Fusarium verticillioides
,
F. graminearum
,
Aspergillus ochraceus
, and
A. nidulans
. Consuming mycotoxin-producing fungi affected the body size and reproductive ability of
F. candida
, and altered the gut bacterial composition, with decreased Proteobacteria and increased Actinobacteria (
Microbacterium
) abundances. Notably, the abundance of foodborne fungi can be detected. Furthermore, certain bacteria isolated from
F. candida
’s gut inhibited the growth of corresponding mycotoxin-producing fungi. The gut bacteria that inhibited mycotoxin-producing fungi growth in
Aspergillus
groups were also associated with poor fitness parameters and larger disruption in gut microbiota. Importantly, switching back to yeast diets reversed both the fitness parameters and gut bacterial composition. Together, our study demonstrated that grazing of mycotoxin-producing fungi by
F. candida
resulted in reduced physiological parameters and disturbed the gut bacterial community, and those changes can be restored by switching back to yeast diets, which indicates a strong resilience of springtails to mycotoxin-producing fungi.

IMPORTANCE

Mycotoxin-producing fungi are widespread in nature and raise concerns for human and livestock health. Although they share the same ecosystem, interactions between mycotoxin-producing fungi and soil arthropods are not well understood. In this study, we report an unexpected finding that the soil arthropod
Folsomia candida
is rather tolerant to these mycotoxin-producing fungi.
F. candida
can survive solely on mycotoxin-producing fungi as a food source with reduced physiological parameters. Moreover, the gut microbial community is disturbed by mycotoxin-producing fungi, and some of the bacteria isolated from
F. candida
’s gut can inhibit the growth of corresponding fungi. Notably, the altered physiological parameters and gut microbiota are restored when a normal diet is reintroduced, suggesting
F. candida
’s resilience to mycotoxin-producing fungi. These findings clarify the impact of toxin-producing diets on
F. candida
, shedding light on how organisms can build resilience to environmental stimuli.
Second resonance of the Higgs field: motivations, experimental signals, unitarity constraints
Authors: Consoli Maurizio , Rupp George
Published: September 2024

Perturbative calculations predict that the effective potential of the Standard Model should have a new minimum, well beyond the Planck scale, which is much deeper than the electroweak vacuum. So far, most authors have accepted the metastability scenario in a cosmological perspective which is needed to explain why the theory remains trapped in our electroweak vacuum but requires to control the properties of matter in the extreme conditions of the early universe. As an alternative, one can consider the completely different idea of a non-perturbative effective potential that, as at the beginning of the Standard Model, is restricted to the pure $$\Phi ^4$$

Φ
4

sector but is consistent with the indications of the now existing analytical and numerical studies, namely “triviality” and a description of SSB as weak first-order phase transition. In this approach, the electroweak vacuum is now the lowest energy state because, besides the state with mass $$m_h=125$$

m
h

=
125

 GeV, defined by the quadratic shape of the potential at its minimum, there is a second much larger mass scale $$(M_H)^\textrm{Theor} \sim 690(30)$$

(

M
H

)

Theor

∼
690

(
30
)

 GeV associated with the zero-point energy determining the potential depth. Despite its large mass, the heavier state would couple to longitudinal Ws with the same typical strength as the low-mass state at 125 GeV and thus represent a relatively narrow resonance mainly produced at LHC by gluon-gluon fusion. Therefore, it is interesting that, in the LHC data, one can find combined indications of a new resonance of mass $$(M_H)^\textrm{comb} \sim 685 (10)$$

(

M
H

)

comb

∼
685

(
10
)

 GeV, with a statistical significance which is far from negligible. Since this non-negligible evidence could become an important new discovery with forthcoming data, we outline further refinements of the theoretical predictions, that could be obtained by implementing unitarity constraints, in the presence of fermion and gauge fields, with the type of coupled-channel calculations nowadays used in meson spectroscopy.
Quantum corrections to tunnelling amplitudes of neutral scalar fields
Authors: Zielinski Rosemary , McGlynn Patrick , Simenel Cédric
Published: September 2024

Though theoretical treatments of quantum tunnelling within single-particle quantum mechanics are well-established, at present, there is no quantum field-theoretic description (QFT) of tunnelling. Due to the single-particle nature of quantum mechanics, many-particle effects arising from quantum field theory are not accounted for. Such many-particle effects, including pair-production, have proved to be essential in resolving the Klein-paradox. This work seeks to determine how quantum corrections affect the tunnelling probability through an external field. We investigate a massive neutral scalar field, which interacts with an external field in accordance with relativistic quantum mechanics. To consider QFT corrections, we include another massive quantised neutral scalar field coupling to the original via a cubic interaction. This study formulates an all-order recursive expression for the loop-corrected scalar propagator, which contains only the class of vertex-corrected Feynman diagrams. This equation applies for general external potentials. Though there is no closed-form analytic solution, we also demonstrate how to approximate the QFT corrections if a perturbative coupling to the quantised field is assumed.
Running of the number of degrees of freedom in quantum conformal gravity
Authors: Giaccari Stefano , Jizba Petr , Kňap Jaroslav , Rachwał Lesław
Published: September 2024

We study how the number of degrees of freedom in Weyl conformal gravity runs with the energy scale from the UV fixed point. To this end we employ two approaches. First, we utilize the Fradkin–Tseytlin prescription for the number of degrees of freedom and demonstrate that the one-loop result is highly dependent on the selected background. We then employ the counting methodology based on the a- and c-function, which are typically used to characterize the trace anomaly of conformal field theories in four dimensions. We compute these in the enhanced one-loop approximation and demonstrate that the degrees of freedom decrease monotonically from six degrees in the UV regime. This behavior is independent of the backgrounds considered. Further salient issues, such as the connection between the Fradkin–Tseytlin prescription and counting based on the a- and c-function, or the applicability of both methods in Einstein’s gravity, are also addressed.
Distributed Bipartite State Consensus Tracking for Discrete-Time Singular Multi-agent Systems
Authors: Zhang Jie , Yao Yao , Wang Jian-An , Ding Da-Wei
Published: September 2024

This paper studies the distributed bipartite state consensus tracking problem of discrete-time linear leader-following singular multi-agent systems (MASs). Compared with the traditional continuous-time linear dynamics, it is difficult to achieve the desired cooperative control of discrete-time counterpart since their stability regions are limited to the unit circle. In addition, in some practical scenarios, there are both cooperation and competition coexisting among followers. First, a new distributed state feedback control protocol is proposed based on the Gerschgorin circle theorem and the discrete algebraic Riccati equation. At the same time, by introducing the constant coupling gain associated with the system topology matrix, the global tracking error system can locate in the stable region of the unit circle. Under the structurally balanced condition of directed signed graph, it can be proved that all the agents of two opposite subgroups can achieve bipartite state tracking by Lyapunov stability theory and separation principle. Then, by using the cooperative–competitive interaction information of neighbours, a new distributed state observer is introduced to estimate the state of leader. Furthermore, when the states of followers are not known, an observer-based output feedback bipartite control protocol is proposed, which can also be applied to more general consensus control scenarios. Meanwhile, a bipartite state formation controller is given to achieve the formation control by making the followers to keep the desired relative positions with the leader. Finally, two simulation results are given to verify the feasibility and effectiveness of proposed algorithms.
Preliminary Report of the Effects of Platelet-Rich Plasma on the Ovarian Function and Oocyte Quality in Women with Ovarian Failure
Authors: Maruta Ei , Koike Hiroko , Fujisawa Yuki , Tsutsumi Osamu
Published: September 2024

This study investigated the effects of platelet-rich plasma (PRP) treatment on ovarian function and pregnancy outcomes in three patients with severe reduction of ovarian reserve. The patients had previously undergone multiple cycles of assisted reproductive technology (ART) without favorable results. Prior to PRP treatment, follicle-stimulating hormone (FSH), estradiol (E2), and anti-Mullerian hormone (AMH) levels were assessed. PRP was administered through intraovarian injection. Hormonal assessments were performed at 6–7 months after the first PRP injection. The results showed major improvements in ovarian function, as evidenced by decreased FSH levels and increased AMH levels in all three patients. The number of mature oocytes retrieved per cycle and the ovum-to-blastocyst rate were also improved. All the patients achieved successful pregnancies and gave birth to healthy infants. These findings suggest that PRP may enhance ovarian function, oocyte quality, and pregnancy outcomes in patients with severely reduced ovarian reserve. Further research is necessary to validate these results and explore the underlying mechanisms.
Experimental Considerations for the Evaluation of Viral Biomolecular Condensates
Authors: Roden Christine A. , Gladfelter Amy S.
Published: September 2024

Biomolecular condensates are nonmembrane-bound assemblies of biological polymers such as protein and nucleic acids. An increasingly accepted paradigm across the viral tree of life is (a) that viruses form biomolecular condensates and (b) that the formation is required for the virus. Condensates can promote viral replication by promoting packaging, genome compaction, membrane bending, and co-opting of host translation. This review is primarily concerned with exploring methodologies for assessing virally encoded biomolecular condensates. The goal of this review is to provide an experimental framework for virologists to consider when designing experiments to (a) identify viral condensates and their components, (b) reconstitute condensation cell free from minimal components, (c) ask questions about what conditions lead to condensation, (d) map these questions back to the viral life cycle, and (e) design and test inhibitors/modulators of condensation as potential therapeutics. This experimental framework attempts to integrate virology, cell biology, and biochemistry approaches.
Are There More Human Cancer Viruses Left to Be Found?
Authors: Moore Patrick S. , Chang Yuan
Published: September 2024

Of the thousands of viruses infecting humans, only seven cause cancer in the general population. Tumor sequencing is now a common cancer medicine procedure, and so it seems likely that more human cancer viruses already would have been found if they exist. Here, we review cancer characteristics that can inform a dedicated search for new cancer viruses, focusing on Kaposi sarcoma herpesvirus and Merkel cell polyomavirus as the most recent examples of successful genomic and transcriptomic searches. We emphasize the importance of epidemiology in determining which cancers to examine and describe approaches to virus discovery. Barriers to virus discovery, such as novel genomes and viral suppression of messenger RNA expression, may exist that prevent virus discovery using existing approaches. Optimally virus hunting should be performed in such a way that if no virus is found, the tumor can be reasonably excluded from having an infectious etiology and new information about the biology of the tumor can be found.
Molecular Dynamics Simulation of Bubble Formation in Confined Water in Si/SiO2 Nanochannels
Authors: Taghavi Nasrabadi Amir , Nishikido Shuuichi , Simms Ihsan , Nakamori Mitsunori
Published: September 2024

We used molecular dynamics simulations to study bubble formation in confined water in Si and SiO2 nanochannels. Our simulations showed that surface wettability plays a major role in determining the mechanism type of bubble formation in confined geometry of nanofeatures. Hydrophobic Si surfaces and hydrophilic SiO2 surfaces led to heterogenous and homogenous bubble formation, respectively. Such observations can help in understanding cavitation effects during etching/cleaning processes of features at nano-scale dimensions.
Evaluation of Metal Contamination Behavior on Silicon Wafer Surfaces Rinsed with Deionized Water Containing pg/L-Level Impurities
Authors: Tsutano Kyohei , Mawaki Takezo , Shirai Yasuyuki , Kuroda Rihito
Published: September 2024

Two tests were performed to investigate the contamination behavior of bare Si wafers by rinsing them using deionized water (DIW) contaminated with metals at the pg/L-level in a single-wafer cleaning process. First, we found that Al, Ti, Mn, Co, Cu, Sr, and Pb exhibited strong correlations between the metal concentrations in DIW and the wafer surface concentrations under different concentrations in DIW and the same rinse time of 480 min. Second, we observed that the wafer surface concentrations of Al, Ti, Cu, and Pb increased with the rinse time, whereas those of Mn, Co, and Sr were constant at rinse times ranging from 10 to 960 min at metal concentrations of 60 pg/L in DIW. In this test, Cu exhibited a high adsorption ratio on bare Si wafers, even at the pg/L level. These data provide novel insights into wet processes for device manufacturing.
Quantitative Modelling of Residual Molecular Contamination in Low-Pressure Processing Environments
Authors: Mertens Paul W.
Published: September 2024

Some published experimental results of organic molecule contamination in vacuum processing are reviewed. The build-up of gaseous contamination from the residual gas in vacuum ambient to the surface of a substrate is quantitatively modelled. Calculations show that the build up of contaminants from the residual gas phase to the surface is very fast, essentially because in very dilute gas there are little molecular collisions to slow down the transport towards the substrate.
(Invited) Advancing Si Spin Qubit Research: Process Integration of Hall Bar FETs on Si/SiGe in a 200mm BiCMOS Pilot Line
Authors: Reichmann Felix , Mistroni Alberto , Yamamoto Yuji , Kulse Philipp , Marschmeyer Steffen , Wolansky Dirk , Fursenko Oksana , Zöllner Marvin Hartwig , Capellini Giovanni , Diebel Laura , Bougeard Dominique , Lisker Marco
Published: September 2024

Hall bar-shaped field-effect transistors (HB-FETs) are excellent devices for comprehensive, large-scale testing of Si/SiGe heterostructures in spin qubit applications. In this paper, we detail the process integration of high-quality HB-FETs onto Si/SiGe heterostructures within the IHP 200 mm BiCMOS pilot line. We compare various SiO2 deposition techniques to identify the most suitable process for a low thermal budget gate dielectric. The integration of HB-FETs on Si/SiGe heterostructures is discussed with a focus on the contact implant. We demonstrate the functionality of the devices at room temperature and at cryogenic temperatures. Magnetotransport measurements reveal a maximum electron mobility exceeding 300,000 cm²/Vs at 1.5 K.
Selective-Area Growth of InGaAs Nanowires on SOI and the Vertical Transistor Application
Authors: Taniyama Keita , Takeda Yuki , Azuma Yuki , Zheng Ziye , Motohisa Junichi , Tomioka Katsuhiro
Published: September 2024

The gate-all-around (GAA) structure avoids the problems inherent in miniaturizing field-effect transistors (FETs), such as off-state leakage current and short-channel effects. Among GAA structures, vertical GAA (VGAA) structures are expected as promising building blocks for future three-dimensional integrated circuit applications. The vertical III-V nanowires (NWs) on Si are expected as the fast channel materials for the VGAA structures on Si platforms. Thus, the combination of the VGAA structure with III-V NWs on Si significantly enhances on-state current while maintaining good gate controllability under low supply voltage. In addition, III-V NWs/Si tunnel junctions, which are formed by the direct integration of vertical III-V NWs on Si, can be utilized as VGAA tunnel FETs (TFETs) for low-power switch. Here we report on direct integration of vertical InGaAs NWs on silicon-on-insulator (SOI) substrates by selective-area growth and demonstrations of InGaAs NW-channel VGAA transistors (FETs and TFETs) on SOI.
Demonstration of VGAA-TFETs using InAs/Si Heterojunction on SOI substrate
Authors: Takeda Yuki , Azuma Yuki , Zheng Ziye , Motohisa Junichi , Tomioka Katsuhiro
Published: September 2024

Tunnel field-effect transistors (TFETs) are expected to be used as a next-generation low-voltage switching device. The TFETs can lower the subthreshold slope (SS) below the physical limit (SS = 60 mV/dec at room temperature) in conventional MOSFETs. Here we demonstrated InAs nanowire (NW)/Si heterojunction vertical gate-all-around (VGAA) TFETs on silicon-on-insulator (SOI) (111) substrates toward vertical integrated circuit applications. The vertical InAs NW channels were grown by selective-area growth on thin SOI(111) substrates.
Selective Epitaxial Growth of SiGe(:B) for Advanced p-Type Fd-SOI
Authors: Lespiaux Justine , Kanyandekwe Joël , Marion Tanguy , Saidi Lazhar , Lapras Valérie , Bond Alice , Bringuier Fabien , Richy Jérôme , Thouvard Alan , Biet Tim , Nolot Emmanuel , Couture Ludovic , Brunet Laurent , Rodriguez Philippe , Dos Reis Eva , Gauthier Nicolas , Blot-Saby Adrien , Hartmann Jean-Michel
Published: September 2024

We focus here on various Selective Epitaxial Growth (SEG) processes used during the manufacturing of advanced p-MOSFET devices: (i) 20 nm thick in-situ boron doped Si0.7Ge0.3 layers grown at 650 °C, 20 Torr then capped with 5 nm of Si:B (at 730 °C, 20 Torr) for Raised Sources and Drains (RSDs) and (ii) 8 nm intrinsic SiGe layers grown at 650–700 °C, 20 Torr for channels. Those layers were grown with a heavily chlorinated chemistry to maintain full selectivity versus SiN hard-mask or SiCO sidewall spacers. The impact of diborane, germane and hydrochloric acid mass-flows on growth kinetics and doping were first of all quantified on blanket wafers. Epitaxial processes were optimized in terms of (i) doping and growth rates, which should be as high as possible while still having superior structural and electrical properties and (ii) selectivity against dielectrics. In a second part, we highlight some of difficulties encountered when switching to patterned substrates. The morphology, faceting and loading effects in such layers are discussed.
High Performance CMOS RF Switch Based on Highly Carbon Doped Raised Source/Drain Regions
Authors: Chollet Antonin , Berbezier Isabelle , Favre Luc , Labrot Maxime , Dura Julien , Melhem Kassem , Duru Romain , Figarols François , Abel Mathieu , Bodnar Sylvie , Bartolotti B.
Published: September 2024

The demand for high-performance Radio Frequency (RF) CMOS RF SOI (Silicon on Insulator) switches has rapidly increased, driven by the need for advanced wireless technologies (1). In this paper we give new insights on high carbon incorporation, where a Si(1-y)Cy layer with 1% of substitutional carbon (y = Csub) is grown on 40 nm on top on silicon. This layer is used for Raised Source/Drain (RSD) to strain the Si channel, for reducing on-state resistivity (Ron) and which should result in a theoretical 16% gain in current (3), (4). Si(1-y)Cy growth parameters were carefully optimized to increase Csub. Firstly, with the reduction of the temperature. Then, with H2 carrier gas reduction and total pressure increase. These two process modifications have a positive impact on the carbon concentration, thanks to the higher growth rate, without layer relaxation (5).
Dose-Dependent Performance of Boron-Implanted Self-Aligned Bottom-Gate IGZO TFTs
Authors: Powell Eli , Kabir Muhammad Salahuddin , Chowdhury Rahnuma Rifat , Manley Robert G. , Zhu Bin , Hirschman Karl D.
Published: September 2024

This work provides an interpretation of donor activation in self-aligned bottom-gate (SA-BG) Indium-Gallium-Zinc Oxide (IGZO) TFTs with ion-implantation of boron (11B+) species as the source/drain treatment. The effect of implant dose on device operation was investigated. Transfer characteristics appeared similar with a boron dose of 1 and 2×1015 cm-2 however, a 45% decrease in max current was observed for devices implanted with a 4×1015 cm-2 dose. Van der Pauw measurements displayed a similar trend; an increase in boron dose resulted in an increase in sheet resistance. A left-shift in transfer characteristics was observed with a greater shift in the 4×1015 cm-2 dose devices, following thermal stability treatments. The existence of two separate boron species is hypothesized, (1) an electrically active donor species involving a relatively small fraction of the total boron concentration and (2) additional boron interstitials and/or other associated defects. A detailed discussion on developed arguments arrived at through analysis of TFT electrical characteristics is presented.
The Performance of PEFC with Marimo-like Carbon Considering Relative Humidity
Authors: Takamura Kohei , Hosokawa Sayaka , Gunji Hiroyuki , Eguchi Mika
Published: September 2024

A proton exchange membrane fuel cell (PEMFC) is powered by humidified fuel and air gases supplied to the cells. We evaluated the effect of the relative humidity (RH) of the fuel and air gases on the I-V performance of the Marimo-like carbon (MC). MC is a higher order structure of carbon fibers. The RH increased the proton conductivity of the Nafion, while excessive humidification caused flooding. The highest maximum power density was 303 mW cm-2 (80% RH) for the Pt/MC and 165 mW cm-2 (60% RH) for the Pt/CB (carbon black). At all the RHs, the maximum power density of the Pt/MC was higher than that of the Pt/CB. The fiber structure and I/C (0.1) of the MC increase the mass diffusivity of the Pt/MC. The high mass diffusivity of the Pt/MC found to reduce flooding and promote the wetting of the Nafion by the generated water.
Effects of Ionomer Film Thickness and Water Content on Oxygen Permeation Properties of PEFC Cathode Catalyst
Authors: Hikida Kengo , Suzuki Hiroto , Tokumasu Takashi
Published: September 2024

In order to promote the widespread use of Polymer Electrolyte Fuel Cell (PEFC), enhancing cell performance is necessary. One significant factor affecting cell performance is the oxygen permeability in the ionomer, which depends on its nano-scale structure. In this study, to investigate the relationship between structures of catalyst layers and cell performances, we analyzed the effects of film thickness and water content on the oxygen permeation properties of ionomer in the cathode catalyst layer of PEFC using molecular dynamics simulations. We constructed a system in which oxygen molecules permeated ionomer on a platinum (Pt) surface. We found that sulfonic acid groups have a significant effect on oxygen permeation in low water content conditions.
Coarse-Grained Molecular Dynamics Simulation of Ionomer-Mediated Carbon Cluster Bonding in Polymer Electrolyte Fuel Cell Catalyst Layers
Authors: Liu Ruoyu , Wang Sirui , Guo Yuting , Huang Sheng-Feng , Tokumasu Takashi
Published: September 2024

This study examines the impact of ionomer to carbon mass ratio and the number of platinum particle clusters on the structural dynamics and organization of Pt-C-Nafion catalyst layers during the evaporation process. Using Coarse-Grained Molecular Dynamics (CGMD) simulations, we analyzed the center of mass position and ionomer coverage on Pt surface. The results show that a higher ionic polymer to carbon mass ratio (0.6) increases lateral mobility and short-range ordering along with the coverage of the Pt surface with ionomers, whereas increasing the number of Pt particle clusters (from 1 to 4 ) enhances lateral diffusion as well as leading to more difficult adsorption of ionomers. These findings highlight the importance of optimizing these parameters to obtain a homogeneous and stable catalyst layer, which is critical for fuel cell performance. Future work will include tuning the Pt/C mass ratio, hydrophilicity, and IC ratio in conjunction with energy and force analyses to further understand the effect of Nafion on Pt/C clusters.
Effect of Deposition Conditions on Properties of Aluminum Deposit Obtained from Aluminum Chloride-Acetamide Melts
Authors: Ito Yuga , Takeguchi Tatsuya , Ui Koichi
Published: September 2024

Although aluminum (Al) electrodeposition using nonaqueous solutions has been widely studied, the process cost is not low. Because aluminum chloride (AlCl3)-acetamide (AcA) deep eutectic solvent (DES) takes low cost and produce better Al deposits than the AlCl3-based ionic liquid in dry air process costs may be reduced. However, the effect of the Al electrodeposition conditions using the AlCl3-AcA DES has not been clear. We investigated the effect of the operating temperature on the properties of Al electrodeposition using the AlCl3-AcA melt. At the operating temperate of 50 °C, the grain shape was fine-scale, similar to the surface morphology of the deposit in the AlCl3-urea melt.In contrast, at the operating temperature of 90 °C, the grain shape changed to fine grains. Based on these results, it was revealed that the grain shape and the preferential orientation of the Al deposit would be affected by operating temperature.
(Invited) Development of Fiber-Optic Hydrogen Sensor Using Platinum-Supported Tungsten Trioxide-Silica Composite Film
Authors: Okazaki Shinji , Ishii Erika , Nishijima Yoshiaki , Arakawa Taro
Published: September 2024

A fiber-optic hydrogen gas sensor using a platinum-supported tungsten oxide-silica composite film was fabricated. This sensor utilizes the absorption of the evanescent field interaction in the hydrogen sensitive clad which was composed of WO3 and SiO2, coated on a silica core with sol-gel process. As a first step, transmission spectra of sensing film itself were measured. The transmittance of the sensitive film decreased in the range of wavelengths above about 500 nm after exposure to pure hydrogen, and the change in transmittance at 1300 nm was greater than that at 850 nm. Then, fiber optic sensor device was fabricated, and the amount of propagating light was measured. In the case of using the light source with a wavelength of 1300 nm, the sensitivity with respect to the hydrogen response was nearly twice and the response speed was faster, compared with those at 850 nm.
Significant Changes in Electrical Resistance of Conductive Porous Silicon Films Produced from Thiol-Modified Silicon Nanoparticle Inks
Authors: Sato Seiichi , Tsubota Shuhei , Ichinohe Takahisa
Published: September 2024

Conductive porous Si films composed of Si nanoparticles were produced by depositing a thiol-modified Si nanoparticle ink and then sublimating the thiol-modification surface, leaving Si–S bonds on the surface. By exchanging atmospheric gas such as N2 and O2, these S-terminated porous Si films reversibly changed electrical resistances in a dynamic range of five orders of magnitude, indicating that the resistance change was due to O2 adsorption/desorption on the S-terminated surface.
Pennington Corner: Membership by Association
Authors: Jannuzzi Christopher J.
Published: September 2024

Beginning in 2025, ECS will offer an Associate membership category to qualifying constituents. However, unlike ECS Members who are required to pay annual dues, Associates pay no fees to join ECS. Instead, Associate membership is based solely on an individual’s engagement with the Society. Qualifications for Associate status might include presenting a paper at an ECS meeting, authoring or peer-reviewing a manuscript submission, or authoring a paper published in an ECS journal. Upon opting into the Associate category, benefits such as discounts on ECS events, products, and services (e.g., Open Access publishing fees), begin immediately. Although Associates do not receive the same discounts as Members and cannot vote or hold an elected position with the Society, there are still significant benefits to joining as an Associate.
Modeling of Li-ion Battery Thermal Runaway: Insights into Modeling and Prediction
Authors: Coman Paul T. , Weng Andrew , Ostanek Jason , Darcy Eric C. , Finegan Donal P. , White Ralph E.
Published: September 2024

This article discusses the dual challenges of modeling and predicting thermal runaway (TR) in li-ion batteries. It explores the current challenges of TR modeling, the methods for progressing from single cells to battery packs, and future directions involving the use of probabilistic methods and ML/AI to tackle this multifaceted issue. Accurate prediction of TR events remains a major challenge, especially because of the cell-to-cell variability, but also due to parametrization, which requires complex experimentation or exhaustive experimental data for training data-driven ML models. Continued research and innovation in modeling and predictive techniques are essential for ensuring safer and more reliable battery systems.
High-Speed Imaging for Investigating Battery Failure Mechanisms
Authors: Reid Hamish T. , Kesuma Inez , Buckwell Mark , Robinson James B. , Shearing Paul R.
Published: September 2024

As the EV and battery market continues to grow, understanding and mitigating battery thermal runaway remains a critically important area of research. Under controlled experimental conditions, researchers have employed a range of different techniques to initiate battery fires and understand both how and why they occur. These tests give important information about how a battery cell catastrophically fails under abuse conditions. However, recognizing the changes in the internal structure of the cell is vital to understanding the mechanisms of thermal runaway which enables the development of effective mitigation strategies. During the last decade, X-ray imaging has emerged as an important diagnostic tool for battery degradation, electrochemical performance, and safety diagnostics. Researchers use X-ray imaging to directly observe the internal changes in the cell during all stages of thermal runaway. Depending on the initiation method, it can sometimes take minutes, hours, or days for a cell to undergo failure. However, the actual final reactions that cause thermal runaway occur over fractions of a second. High-speed cameras, operating at up to 40,000 frames per second, can capture the interactions between electrodes at the final moments of thermal runaway. In this article, the basics of high-speed X-ray imaging and how this technique has been applied to investigating battery thermal runaway are discussed.
Formula of Cylindrical Spring Stiffness for Nonlinear Large Deformation and Its FEM Verification
Authors: Huang Zhi , Xiao Fengying , Zhu Risheng , Rao Chunhua , Huang Mojia , Zhao Tengfei , Yin Huajie
Published: September 2024

Springs are fundamental components in mechanical systems, crucial for ensuring the safety and functionality of mechanisms. Timoshenko’s stiffness formula accounts for both bending and torsional energy effects, providing accurate results for small deformations. However, when the deformation becomes large, the spring stiffness becomes a nonlinear problem due to the changing inclination angle and radius during deformation. In this study, we derive a formula for the cylindrical spring stiffness under nonlinear large deformation by considering two assumptions: the invariability of the polar angle at any point and spring wire length during deformation. This formula incorporates the effects of inclination and radius changes on the spring wire. We analyze the stiffness of the cylindrical spring with different initial inclinations using the finite element method (FEM). FEM results were compared with those obtained from Timoshenko’s formula, Hiroyuki’s formula, and the derived formula. For small deformations, the FEM results matched well with all three formulas. However, for nonlinear large deformations, the calculated results from Timoshenko’s formula showed a discrepancy of up to 32.58% compared to the FEM results. The modified Hiroyuki formula also exhibited slightly poorer agreement with the FEM results than the formula proposed in this paper. On the other hand, our derived formula demonstrated excellent agreement with the FEM results for nonlinear large deformations. Therefore, our stiffness formula for cylindrical springs is recommended for mechanical engineering spring design applications involving nonlinear large deformations.
Design and Development of Vortex Generators on Cylindrical Tower
Authors: Boonloi Amnart , Sudsanguan Anan , Jedsadaratanachai Withada
Published: September 2024

This work presents a numerical study on flow configurations and pressure distribution of cylindrical towers attached with different shapes of vortex generators. The vortex‐generator attachment is done with the main aim of reducing the energy of ventilation for the cylindrical tower. The two different types of vortex generators, namely, a cylindrical‐shaped vortex generator and a diffuser‐shaped vortex generator, are compared with an original square‐shaped vortex generator. The effects of air velocity (2, 4, 6, and 8 m/s) and vortex generator size (D/2, D, and 2D) on flow structure are considered. The finite element method (a commercial code) is selected for the main problem‐solving. The numerical models of the cylindrical towers attached with various vortex generators are validated to confirm the reliability of the numerical results. From the numerical results, it was found that the suctioned updraft speed in the tower was proportional to the crosswind speed. In addition, the vortex generator with h = 2D performs the highest updraft speed, which leads to the best efficiency for ventilation.