bluuebunny/crossref_metadata_2025 huggingface dataset:
Directed colloidal assembly and banding via DC electrokinetics
Authors: Shin Sangwoo
Published: May 2023

Manipulating the transport and assembly of colloidal particles to form segregated bands or ordered supracolloidal structures plays an important role in many aspects of science and technology, from understanding the origin of life to synthesizing new materials for next-generation manufacturing, electronics, and therapeutics. One commonly used method to direct colloidal transport and assembly is the application of electric fields, either AC or DC, due to its feasibility. However, as colloidal segregation and assembly both require active redistribution of colloidal particles across multiple length scales, it is not apparent at first sight how a DC electric field, either externally applied or internally induced, can lead to colloidal structuring. In this Perspective, we briefly review and highlight recent advances and standing challenges in colloidal transport and assembly enabled by DC electrokinetics.
Vortex-induced vibration of two circular cylinders in a side-by-side arrangement at moderate Reynolds number: A numerical study
Authors: Irawan Yosua Heru , Raza Syed Ahmad
Published: May 2023

Vortex-induced vibration (VIV) of two transversely vibrating cylinders in a side-by-side (SBS) arrangement is numerically investigated using a combination of direct-forcing immersed boundary and large eddy simulation techniques. The VIV responses of vibrating SBS cylinders at two reduced velocities (UR* = 4.0 and 6.0) are studied for a range of gap ratio 1.0 ≤g*≤ 3.0. Moreover, the influence of mass ratio, damping ratio, and Reynolds number in the amplitude response and efficiency of VIVACE (Vortex-Induced Vibration for Aquatic Clean Energy) from vibrating SBS cylinders are investigated at moderate Reynolds numbers (Re = 1000 and 10 000). The optimal gap ratio for UR* = 4.0 is in the range of 1.0 ≤g*≤ 1.2. Larger than this range, the VIV responses are close to single-cylinder responses. At UR* = 6.0, all gap ratios show lower responses than a single-cylinder case. The vibrating SBS cylinder with a larger damping ratio results in higher maximum VIVACE efficiency with a narrower UR* range for significant efficiency. With almost the same amplitude response, the SBS cylinders with a lower mass ratio result in lower VIVACE efficiency. Using the same mass-damping parameters, it appears that a low mass ratio could be desirable to increase the UR* range of significant VIVACE efficiency and pick the proper damping ratio to reach a high value of maximum VIVACE efficiency. The effect of flow conditions on the amplitude response and VIVACE efficiency of vibrating SBS cylinders with the same VIV parameters is not significant.
Study on the properties of enhanced plasma injection driven by electrical explosion of aluminum wire in PTFE capillary in high-pressure SF6
Authors: Li Xiaoang , Jiang Pan , Li Zhibing , Zhang Ran , Zhao Ke , Zhang Ningbo , Zhang Qiaogen
Published: May 2023

Enhanced plasma injection (EPI) driven by the electrical explosion of a metal wire in a microcavity has been proven to be an effective method for triggering 10-cm-magnitude high-pressure SF6 gas gap at very low working coefficients and provides a potential technical routine for ultrafast bypass switches (UFBPSs). In this study, aiming to further promote the EPI strength and improve its triggering ability, the EPI actuator is optimized, and several vital parameters of the actuator structure, including diameter D and length L of the microcavity and nozzle shape, are investigated. EPI with a maximum height of ∼10 cm and an initial velocity of ∼1000 m/s can be realized in 0.5 MPa SF6 when a 600 μm aluminum wire is exploded by a ∼1000 J trigger pulse. The EPI strength vs D curve has an inverted V shape, and 2 mm D results in the most intense EPI, due to the competitive effect of the vent congestion inside a thin capillary and parasitic volume in a fat capillary. As L increases, the EPI strength increases to saturation and then decreases. A 20–23 mm L can yield suitable EPI strength with limited trigger energy. The nozzle shape has a remarkable influence, and a divergent-type nozzle leads to a much stronger EPI than the shrink-type or straight-type nozzle, generating an EPI with a maximum height of 12 cm and an initial velocity of 1600 m/s. This study provides a useful guidance for the EPI actuator design for triggering megavolt UFBPSs at very low working coefficients.
Complex magnetic ordering behavior in the frustrated perovskite Ba2MnMoO6
Authors: Coomer Fiona C. , Mutch Heather M. , Mustonen Otto , Pughe Charlotte , Cussen Serena A. , Ramos Silvia , Hillier Adrian D. , Cussen Edmund J.
Published: May 2023

New and exotic ground states of magnetic materials are highly sought after and are extensively studied for the insights they provide into the thermodynamics of disorder and fundamental magnetic interactions. By controlling the crystal structure of an appropriate magnetic lattice, it is possible to cause the strong magnetic exchange interactions to sum to zero and so be frustrated. Due to the presence of this frustration, the lowest energy configuration that results may be crucially dependent on the tiniest of energy differences between a multitude of states that have (almost) the same energy. The keen interest in these materials arises from the fact that these finely balanced systems offer a way of probing classical or quantum mechanical interactions that are of fundamental importance but are too weak to be observed in non-frustrated systems. Here, we combine local and crystallographic probes of the cation-ordered double perovskite Ba2MnMoO6 that contains a face-centered cubic lattice of S = 5/2 Mn2+ cations. Neutron diffraction measurements below 9.27(7) K indicate that a fourfold degenerate non-collinear antiferromagnetic state exists with almost complete ordering of the Mn2+ spins. Muon spin relaxation measurements provide a local probe of the magnetic fields inside this material over the t1/2 = 2.2 µs lifetime of a muon, indicating a slightly lower Néel transition temperature of 7.9(1) K. The dc susceptibility data do not show the loss of magnetization that should accompany the onset of the antiferromagnetic order; they indicate that a strongly antiferromagnetically coupled paramagnetic state [θ = −73(3) K] persists down to 4 K, at which temperature a weak transition occurs. The behavior of this material differs considerably from the closely related compositions Ba2MnMO6 (M = W, Te), which show collinear ordering arrangements and well defined antiferromagnetic transitions in the bulk susceptibility. This suggests that the Mo6+ cation leads to a fine balance between the nearest and next-nearest neighbor superexchange in these frustrated double perovskite structures.
Enhancing the bubble collapse energy using the electrohydrodynamic force
Authors: Taleghani Mohammad Hassan , Khodadadi Sajad , Maddahian Reza , Mokhtari-Dizaji Manijhe
Published: May 2023

The energy released during the bubble collapse process is used for medical and industrial purposes. The present study investigates the effects of electrohydrodynamic force on the collapse phenomenon near the rigid wall and the enhancement of the collapse energy. A solver in the OpenFoam open-source code is developed based on the volume-of-fluid model, in which the effects of compressibility, energy transfer, and electrohydrodynamic force are included. The developed solver is validated against the available experimental data, and a good agreement is seen. The effects of an electric field on the bubble collapse for the range of the electrocapillary number (CaE) of 0–5.76 and normalized wall distance (γ) of 0.8–2.0 are investigated. The results indicate that the bubble is deformed due to the presence of an electric field, and the values obtained for the maximum velocity and pressure are 33 and 35 times the state without the electric field at γ = 2 and CaE = 5.76, respectively. Also, due to the increase in velocity, the maximum shear stress on the rigid wall is increased up to seven times in the absence of the electric field. Therefore, the jet force obtained from the bubble collapse can be enhanced by applying the electric field in the continuous phase fluid. Also, the correlations are proposed to estimate the jet velocity, pressure, and wall shear stress of bubble collapse in the presence of an electric field.
Halide alloying and role of central atom on the structural and optical properties of decylammonium germanium 2D perovskites
Authors: Chiara Rossella , Accorsi Gianluca , Listorti Andrea , Coduri Mauro , Coccia Clarissa , Tedesco Costanza , Morana Marta , Malavasi Lorenzo
Published: May 2023

We report here a novel series of halide alloyed Ge-containing 2D perovskites including decylammonium as organic spacer, namely DA2Ge(Br1−xIx)4. This system forms a continuous solid solution on the halide site with a modulation of the bandgap from 2.74 to 2.17 eV with a rapid decrease up to x = 0.5 followed by a plateau. Iodide-rich compositions show enhanced broad room temperature (RT) photoluminescence (PL) that narrows at low temperature with maximum quantum yields for mixed compositions. The replacement of Ge with Pb and Sn in DA2GeBr4 and DA2GeI4 provides a tuning of the bandgap in the whole visible spectrum with a marked blue-shift when lead is present and, opposite, a red-shift for Sn replacement. The RT PL progressively broadens moving from Pb to Sn and to Ge covering an emission range from 400 to 800 nm. Finally, the air stability of lead-free 2D perovskites of this work has been determined indicating its improvement by increasing the hardness of the halide.
Prospects for inorganic CsPbI3 perovskite solar cells with commercially viable lifetimes
Authors: Kaplan Alan B. , Burlingame Quinn C. , Holley Rudolph , Loo Yueh-Lin
Published: May 2023

Perovskite CsPbI3 is a promising photovoltaic absorber material, thanks to its ideal bandgap for Si-tandem solar cell applications and its excellent thermochemical stability compared with hybrid organic–inorganic perovskites. However, CsPbI3 has its own stability challenges as its photoactive β- and γ-polymorphs are thermodynamically unstable at room temperature compared with the yellow non-perovskite δ-phase. Stabilizing CsPbI3 has, thus, been the subject of considerable research in recent years. While some approaches, such as alloying with halides and reducing crystalline domain size, have proven effective in improving phase stability, these benefits have, thus far, come at the expense of photovoltaic efficiency compared with the state-of-the-art CsPbI3 solar cells. In this perspective, we discuss the progress and limitations of inorganic perovskite stabilization techniques and look forward at how to achieve inorganic perovskite solar cells with both commercially viable efficiencies and lifetimes.
High spin polarization and spin signal enhancement in non-local spin valves with Co–Fe alloy injectors and detectors
Authors: Kaiser B. , Ramberger J. , Watts J. D. , Dewey J. , Leighton C.
Published: May 2023

For applications such as spin accumulation sensors for next-generation hard disk drive read heads, and for fundamental research, it is desirable to increase the spin signal in metallic non-local spin valves, which are central devices in spintronics. To this end, here, we report on the integration of high-spin-polarization Co–Fe binary alloy ferromagnetic injectors and detectors in Al-based non-local spin valves. Room-temperature deposition on amorphous substrates from an alloy target is shown to generate smooth, polycrystalline (110-textured), solid-solution body-centered-cubic Co75Fe25 films, which we characterize by energy dispersive x-ray spectroscopy, x-ray diffraction, x-ray reflectivity, atomic force microscopy, and electronic transport. Simple integration into transparent-interface Al non-local spin valves is then shown to realize up to a factor of ∼5 enhancement of the spin signal relative to Co, with full quantitative analysis yielding strikingly temperature-independent current spin polarizations exceeding 60%. We make a detailed quantitative comparison of these values with prior literature, concluding that Co–Fe alloys present a remarkably facile route to higher spin polarization and spin signals in non-local spin valves, with minimal barrier to adoption.
Explicit Nth order solutions of Fokas–Lenells equation based on revised Riemann–Hilbert approach
Authors: Zhang Yongshuai , Qiu Deqin , He Jingsong
Published: May 2023

We develop a revised Riemann–Hilbert problem (RHP) to the Fokas–Lenells (FL) equation with a zero boundary condition, satisfying the normalization condition, and the potential of the FL equation is recovered from the asymptotic behavior of RHP when the spectral parameter goes to zero. Under the reflection-less situation, we consider the RHP with 2N simple poles and two Nth order poles, respectively, and obtain the explicit formulas of Nth order soliton and positon solutions. As applications, the first-order soliton, the second-order soliton, and positon are displayed. Additionally, the collisions of N solitons are studied, and the phase shift and space shift are displayed.
Linear characteristics of dust acoustic waves in two dimensional inhomogeneous complex plasmas
Authors: Zhang Liping , Wang Xingju , Zheng Jiangqiong , Su Junyan
Published: May 2023

This paper explores dust acoustic waves (DAWs)’ instability in two dimensional nonuniform complex plasmas. For this purpose, the dispersion relation is obtained using the method of separation of variables. In the process of linearizing the hydrodynamic equations describing the characteristics of two dimensional nonuniform complex plasma equations, the temporal and spatial dependence of all perturbations is assumed to be proportional to A1(x, y)exp[−iωt]. It is shown that the inhomogeneities in indifferent directions have different influences on the linear dispersion characteristics of DAWs. The numerical results show that the present research results are very important in the phenomenon of space astrophysical and experimental plasmas.
Determining the height of deep volcanic eruptions over the tropical western Pacific with Himawari-8
Authors: Lucas Chris
Published: May 2023

Volcanic eruptions are significant aviation hazards due to the formation of airborne volcanic ash clouds. Further, deep eruptions that reach the upper troposphere and lower stratosphere may have significant weather and climate impacts. A key variable for both dispersion model forecasting for aviation hazards and understanding climate impacts is the volcanic plume height. This work presents a method to quickly and reliably estimate the maximum plume heights of volcanic eruptions that interact with the tropical tropopause layer in the tropical western Pacific region. The method uses infrared (11.2 μm) data from Himawari-8 to identify ‘stratospheric warm spots’ in optically thick portions of the eruption cloud top by searching for reversals in the local-brightness temperature gradient. The brightness temperature of these warm spots is converted to height using seasonal stratospheric reference temperature profiles derived from 20 years of radiosonde data from 17 stations spread throughout the western Pacific. An approach for estimating the height of cold ‘overshooting tops’ is also adopted. Based on the radiosonde data, estimates of the uncertainty in the plume height depend on the height and range within 0.5–5.0 km. A case study of the 19 December 2021 eruption of Hunga Tonga-Hunga Ha’apai demonstrates the technique. The heights are robustly determined with this simple technique and compare well with height estimates of eruptions in the literature that use more complex satellite techniques.
Type does matter!
Authors: Schmid Pascale , Carim jr. Guido , Sargent David , Falla Dominique
Published: May 2023

Electronic documentation is gaining importance in aviation and
medicine. However, the literature on typographic conventions is rather
scattered. Therefore, this systematic literature review examined the landscape
of literature addressing typography in electronic documentation in aviation and
medicine. The research examined the presence of typographic considerations,
level of depth, choice of medium and documentation examples. The results
demonstrate that out of 65 publications, 35 address typography in varying depth
and often rely on inherited misconceptions. Typographic conventions are
transferred from physical to electronic mediums without questioning and remain
undervalued. These findings highlight the need for improved legibility in
electronic documentation.
(Re)construction of teacher identities in a soft-CLIL context
Authors: Gülşen Erhan , Dikilitaş Kenan
Published: May 2023

This study investigates 4 secondary school Turkish EFL teachers’ perceptions of their experiences in a new Soft-Content and Language Integrated Learning (CLIL) context and explores whether these experiences led to the (re)construction of their identities. The data was collected through a focus group interview, netnography, and stimulated recalls and analyzed on the basis of inductive content analysis. According to the findings, role conflicts caused by lack of pedagogical knowledge on how to integrate content and language impeded a construction of an encompassing CLIL teacher identity. Therefore, ultimately, identity (re)construction was based on either content or language teacher identities. Adopting an interpretive paradigm, our study highlights the importance of investigating new CLIL teachers’ perceptions of their experiences in understanding their identity (re)constructions. It could thus offer implications for similar contexts, particularly by showing the importance of gathering teachers’ perceptions of experiences for CLIL teacher development.
The use of invitations to bid in classroom interaction
Authors: Park Jae-Eun
Published: May 2023

This study explores the interactional meaning of an invitation to bid in Korean elementary school EFL classroom interaction by adopting a conversation analytic perspective. The study argues that participants use invitations to bid to indicate that a question elicits knowledge worthy of public demonstration. The analysis of thirteen video-recorded EFL lessons revealed that teachers use invitations to bid, fulfilling instructional agenda or demands whether they are set up at the beginning of an activity or arise midway. Students similarly invite themselves to bid, showing their understanding of the meaning that the practice carries. While teachers overwhelmingly accept students’ self-invitations, they may reject them in light of the details of instructional here and now. It is argued that deciding which student population should reply is a matter of negotiation although teachers have the final say, oriented to consequences of turn allocation on the work of teaching in progress.
Effects of processing parameters on the LPBF-deposited AlSi10Mg/SiCp composite: microstructure and mechanical properties
Authors: Chen Yan , Jian Zengyun , Li Kan , Song Kang , Ren Yongming , Liu Yongqin , Dang Bo , Zhu Man , Gao Qian
Published: May 2023

Adding SiC particle (SiCp) to Al alloys to form Al/SiCp composite can increase the elastic modulus and reduce the thermal expansion coefficient of the material. In this study, the microstructure, porosity and thermal expansion coefficient, and mechanical properties of AlSi10Mg-10 vol.% SiCp composite fabricated by laser powder bed fusion (LPBF) were investigated. The ultimate tensile strength, compressive strength, compressive modulus, and the thermal expansion coefficient of LPBF-deposited AlSi10Mg/SiCp composite are 351, 861.9 MPa, 121.9 GPa and 18.23 × 10−6°C−1, respectively. The results demonstrate that the use of the Ev equation to evaluate the effect of LPBF parameters on mechanical properties and relative density of the composites is accurate when only one parameter changes in the Ev equation.
Infrared laser ablation dynamics using light scattering
Authors: Deenamulla Achala , Murray Kermit K
Published: May 2023

The dynamics of infrared laser ablation at atmospheric pressure was studied employing continuous visible laser light scattering in the expanding plume. A pulsed infrared optical parametric oscillator at 2940 nm wavelength and 5 ns pulse width was used to irradiate samples comprising liquid glycerol or 50 µm thick sections of rat liver tissue. The scattered light from the expanding laser ablation plume was measured using a 532 nm continuous laser parallel to the target and several millimeters above the ablated spot. The scattered light was recorded using a photomultiplier detector and the signal used to estimate the time at which the plume front passed through the continuous laser beam. The velocity of the ablation plume was obtained from consecutive time and distance measurements and the fraction of the laser energy transferred to the expanding shock wave was determined using the Taylor shock wave model. Plume modeling calculations indicate that the ablation is driven by phase explosion that is thermally confined and near the stress confinement regime.
Optimal design of iron-cored coil sensor in magnetic flux leakage detection of thick-walled steel pipe
Authors: Wang Rongbiao , Yu Haozhi , Tang Jian , Feng Bo , Kang Yihua , Song Kai
Published: May 2023

Thick-walled steel pipes, which bear high internal pressure, are widely applied in nuclear power and pressure pipelines. If there are defects in the inner wall, they are easy to expand and cause accidents. Therefore, the thick-walled steel pipe must be subject to non-destructive testing after production. For the magnetic flux leakage (MFL) testing method, the detection sensitivity gradually decreases with the increase of wall thickness. To solve this problem, a new structure of MFL probe is proposed in this paper. The influence of the iron core permeability on the MFL signal is analyzed theoretically, and the effect of the core length and diameter on the MFL signal is analyzed by simulation. The variation of the MFL signal with the change of the iron core and coil lift-off is studied respectively. The simulation results are verified by experiments. It is found that the lift-off of the iron-cored coil is determined by the iron core position. Based on this phenomenon, an MFL array probe is designed, which can be used for online detection of thick-walled steel pipes to improve the detection sensitivity of inner wall defects.
Cost-effective experiments with additively manufactured waveguide and cavities in the S-band
Authors: Karatay Anıl , Yılmaz Hasan Önder , Özkal Ceren , Yaman Fatih
Published: May 2023

This study demonstrates the applicability of additively manufactured components that are metalized with conductive tape for two different microwave experiments. We focus on dielectric measurements and prototyping elliptical accelerator cavities at a low power regime for 2.45 GHz. To illustrate the accuracy of our results for the commonly used solid/liquid materials in engineering and to compare the fundamental accelerator cavity parameters with previous research rectangular and elliptic 3D-printed cavities coated with aluminum-type tape were employed in the experiments. Results reported for the complex-valued permittivities and specific design parameters for the cavity prototype are consistent with the literature. Various approaches to obtain the conductivity value of the tape and the effect of the roughness/thickness of the coating on the reflection parameter are discussed in detail. We confirm the effectiveness of the proposed approach, which reduces costs and provides a high degree of accuracy for investigated applications.
Investigation of iron oxide shell and iron core in magnetically-assisted synthetized wire-like nanochains
Authors: Krajewski Marcin , Liou Sz-Chian , Kubacki Jerzy
Published: May 2023

The zerovalent iron (Fe0) nanomaterials tend to be spontaneously oxidized in the presence of oxygen. This leads to the formation of interface composed of iron core and thin iron oxide shell. These structures are frequently observed with transmission electron microscope but, at the same time, it is hard to determine the precise structural and chemical composition of oxide shell. This feature is very important for possible applications of Fe0 nanostructures. Hence, the present work aims to deliver more detailed insights in this topic. The investigations are performed for the iron nanochains prepared in the magnetic-field-induce reduction of FeCl3 by NaBH4. The high-resolution transmission electron microscopy, electron energy loss spectroscopy, and x-ray photoemission spectroscopy confirm that the iron nanochains are covered by very thin oxide layer not exceeding over 3 nm. Moreover, the detailed XPS analyses of O 1s and Fe 2p lines indicate that the iron oxide shell reveals Fe3O4 nature. Moreover, this work demonstrated that some by-products of the reaction containing boron are presented in the sample even after a removal of the thin iron oxide shell by Ar+ treatment.
Metal-insulator crossover in monolayer MoS2
Authors: Castillo I , Sohier T , Paillet M , Cakiroglu D , Consejo C , Wen C , Wasem Klein F , Zhao M-Q , Ouerghi A , Contreras S , Johnson A T Charlie , Verstraete M J , Jouault B , Nanot S
Published: May 2023

We report on transport measurements in monolayer MoS2 devices, close to the bottom of the conduction band edge. These devices were annealed in situ before electrical measurements. This allows us to obtain good ohmic contacts at low temperatures, and to measure precisely the conductivity and mobility via four-probe measurements. The measured effective mobility up to μ
eff = 180 cm2 V−1 s−1 is among the largest obtained in CVD-grown MoS2 monolayer devices. These measurements show that electronic transport is of the insulating type for σ ≤ 1.4e
2/h and n ≤ 1.7 × 1012 cm−2, and a crossover to a metallic regime is observed above those values. In the insulating regime, thermally activated transport dominates at high temperature (T > 120 K). At lower temperatures, conductivity is driven by Efros–Schklovkii variable range hopping in all measured devices, with a universal and constant hopping prefactor, that is a clear indication that hopping is not phonon-mediated. At higher carrier density, and high temperature, the conductivity is well modeled by the Boltzmann equation for a non-interacting Fermi gas, taking into account both phonon and impurity scatterings. Finally, even if this apparent metal-insulator transition can be explained by phonon-related phenomena at high temperature, the possibility of a genuine 2D MIT cannot be ruled out, as we can observe a clear power-law diverging localization length close to the transition, and a one-parameter scaling can be realized.
Trap-assisted enhancement of the responsivity in asymmetric planar GaN-based nanodiodes at low temperature
Authors: Pérez-Martín E , Sánchez-Martín H , González T , Mateos J , Íñiguez-de-la-Torre I
Published: May 2023

The microwave detection capability of GaN-based asymmetric planar nanodiodes (so-called Self-Switching Diode, SSD, due to its non-linearity) has been characterized in a wide temperature range, from 70 K up to 300 K. At low temperature, microwave measurements reveal an enhancement of the responsivity at frequencies below 1 GHz, which, together with a pronounced hysteresis in the DC curves, indicate a significant influence of the surface states. This leads to a significant variability and non-repeatability which needs to be reduced since it degrades the accuracy of the detection. For this sake, the RF characterization was repeated after applying a positive/negative voltage able to fill/empty the surface states in order to have a well-established preconditioned state. As a consequence of the positive pre-soak bias, a significant enhancement of the measured responsivity, with a × 10 increase at low temperature. The RF detection measurements after such preconditioning contains a time dependence induced by the slow discharge mechanism of the traps, so that the improved responsivity remains even after 100s of seconds. On the other hand, a negative voltage pre-soak benefits the discharge process, thus suppressing the low frequency dispersion and the important variability of the detection without the pre-conditioning step. We also show that the relation between the voltage and current responsivities in each case allows to explain the impact of the surface charges in terms of the device impedance.
Evaluating the effect of setup uncertainty reduction and adaptation to geometric changes on normal tissue complication probability using online adaptive head and neck intensity modulated proton therapy
Authors: Lalonde Arthur , Bobić Mislav , Sharp Gregory C , Chamseddine Ibrahim , Winey Brian , Paganetti Harald
Published: May 2023

Objective. To evaluate the impact of setup uncertainty reduction (SUR) and adaptation to geometrical changes (AGC) on normal tissue complication probability (NTCP) when using online adaptive head and neck intensity modulated proton therapy (IMPT). Approach. A cohort of ten retrospective head and neck cancer patients with daily scatter corrected cone-beam CT (CBCT) was studied. For each patient, two IMPT treatment plans were created: one with a 3 mm setup uncertainty robustness setting and one with no explicit setup robustness. Both plans were recalculated on the daily CBCT considering three scenarios: the robust plan without adaptation, the non-robust plan without adaptation and the non-robust plan with daily online adaptation. Online-adaptation was simulated using an in-house developed workflow based on GPU-accelerated Monte Carlo dose calculation and partial spot-intensity re-optimization. Dose distributions associated with each scenario were accumulated on the planning CT, where NTCP models for six toxicities were applied. NTCP values from each scenario were intercompared to quantify the reduction in toxicity risk induced by SUR alone, AGC alone and SUR and AGC combined. Finally, a decision tree was implemented to assess the clinical significance of the toxicity reduction associated with each mechanism. Main results. For most patients, clinically meaningful NTCP reductions were only achieved when SUR and AGC were performed together. In these conditions, total reductions in NTCP of up to 30.48 pp were obtained, with noticeable NTCP reductions for aspiration, dysphagia and xerostomia (mean reductions of 8.25, 5.42 and 5.12 pp respectively). While SUR had a generally larger impact than AGC on NTCP reductions, SUR alone did not induce clinically meaningful toxicity reductions in any patient, compared to only one for AGC alone. Significance Online adaptive head and neck proton therapy can only yield clinically significant reductions in the risk of long-term side effects when combining the benefits of SUR and AGC.
Altered the structural, morphological and optical properties of SbSe thin films through swift heavy ion irradiation
Authors: Singh Harpreet , Singh Palwinder , Singh Kamaljit , Singh Fouran , Pratap Singh Abhinav , Kumar Akshay , Thakur Anup
Published: May 2023

Chalcogenide based phase change materials are gaining attention due to their ability to exhibit expeditious and reversible structural transition from amorphous to crystalline phase. This work included the effect of swift heavy silver (Ag9+) ion-irradiation (120 MeV), at various fluences (5E11, 1E12, 5E12 and 1E13 ions/cm2) on the structural, optical and morphological properties of pristine and annealed (250 ° C) SbSe thin films. The pristine films undergo a structural transition from amorphous to crystalline upon annealing and from crystalline to amorphous upon irradiation of annealed films. Structural transition caused by annealing and ion-irradiation resulted in a drastic change in morphology and optical properties. The annealed films exhibited less transmission than the pristine and irradiated films, which increased with increase in ion-irradiation fluences because of phase transition. After irradiation, the optical band decreased for pristine thin films, because the forbidden gap defect concentration has increased, but increased after irradiating the annealed thin films that may be due to annealing out of dense localized defect states. The significant optical contrast upon phase transition in near infrared region can be utilized for different optoelectronic applications.
Quantification of the robustness of functional neural networks: application to the characterization of Alzheimer’s disease continuum
Authors: Revilla-Vallejo Marcos , Gómez Carlos , Gomez-Pilar Javier , Hornero Roberto , Ángel Tola-Arribas Miguel , Cano Mónica , Shigihara Yoshihito , Hoshi Hideyuki , Poza Jesús
Published: May 2023

Objective. Brain connectivity networks are usually characterized in terms of properties coming from the complex network theory. Using new measures to summarize the attributes of functional connectivity networks can be an important step for their better understanding and characterization, as well as to comprehend the alterations associated with neuropsychiatric and neurodegenerative disorders. In this context, the main objective of this study was to introduce a novel methodology to evaluate network robustness, which was subsequently applied to characterize the brain activity in the Alzheimer’s disease (AD) continuum. Approach. Functional connectivity networks were built using 478 electroencephalographic and magnetoencephalographic resting-state recordings from three different databases. These functional connectivity networks computed in the conventional frequency bands were modified simulating an iterative attack procedure using six different strategies. The network changes caused by these attacks were evaluated by means of Spearman’s correlation. The obtained results at the conventional frequency bands were aggregated in a correlation surface, which was characterized in terms of four gradient distribution properties: mean, variance, skewness, and kurtosis. Main results. The new proposed methodology was able to consistently quantify network robustness. Our results showed statistically significant differences in the inherent ability of the network to deal with attacks (i.e. differences in network robustness) between controls, mild cognitive impairment subjects, and AD patients for the three different databases. In addition, we found a significant correlation between mini-mental state examination scores and the changes in network robustness. Significance. To the best of our knowledge, this is the first study which assesses the robustness of the functional connectivity network in the AD continuum. Our findings consistently evidence the loss of network robustness as the AD progresses for the three databases. Furthermore, the changes in this complex network property may be related with the progressive deterioration in brain functioning due to AD.
Research on Dynamic Gunnery Problem Solution Based on Exterior Ballistic
Authors: Li Rui , Zhang Long , Lu Yu-xiang , Wang Yu
Published: May 2023

Abstract:In order to solve the problem of dynamic gunnery problem solution under fire maneuver condition, this paper proposes a method of hitting the moving targets with rapid fire in the maneuver weapon. Based on the exterior ballistics model, objective model, the dynamic gunnery problem solution model is established. The improved particle swarm optimization (PSO) is adopted to calculate the ballistic data. In the process of realizing the algorithm, the angle of firing, azimuth and flight time of projectile are calculated iteratively synchronously, so as to improve the efficiency of the solution by eliminating the initial time assignment step. Considering the sustained rapid fire of maneuver weapon, the adjusting parameters of fire control elements for dynamic shooting are provided by solving the first and last firing ballistic data. The feasibility of the algorithm is verified by simulation experiment.
The Reliability Optimization of a ShipborneDevice by Surrogate Modelling
Authors: Li YD , Wang W , Wang JW , Cao ZC , Kang ZK
Published: May 2023

A Shipborne Weapon Device is not only affected by repetitive and low tense bumping impact, but also warship swing and tilt caused by sea wind and wave. To study on the influences in warship mechanical environment on working reliability of shipborne weapon device, the positioning accuracy of a large caliber naval gun rotary magazine is researched. A automated simulation process is carried out in a multidisciplinary design environment. A more accurate surrogate modelling is first set up based on design of experiments technique, and reliability design and optimization are established sequentially, the positioning accuracy reliability of the rotary magazine is increased from 50.2% to 99.3%. In experimental testing phase, the simulation model is verified and corrected based on test data, and the simulation accuracy is ensured, and test limitations are compensated by simulation in addition. This method can promote the work reliability of similar shipborne devices in warship complicated working conditions.
Effect of Initial Loading Position on the Propellant Particles Distribution in Two-module Charge
Authors: Chen A , Yu Y G
Published: May 2023

The propellant particles distribution in the ignition process of the modular charge has a significant effect on the interior ballistic stability. Thereinto, the particles final distribution is determined by the particles motion process. Based on the CFD-DEM method, a 3D transient gas-solid flow model is constructed to investigate the motion process and the dispersion of propellant particles. Moreover, the cold state test of the ignition process of modular charge is accomplished based on a visual ignition test platform. The simulated data are consistent with the test one. Furthermore, the effect of the initial loading position on the propellant particles distribution of two-module charge is predicted by the numerical simulation. All of two-module cases show that the distributions of particles are made up of a gentle-downhill, a horizontal, and a steep-uphill accumulation. As the initial loading position of modules moves to the right, the slope angle of the uphill is decreased first and then increased, with the minimum slope angle of 20.5°. When the initial loading position of modules is 40mm, the spatial distribution gradient of particles gets the minimum in the uphill accumulation area, and the particles axial-distribution is the most uniform.
Research on spin reduction mechanism of the projectile sliding belt in bore
Authors: Peng J C , Jiang J W , Kang H B , Liao W
Published: May 2023

The sliding belt assembly plays a key role in spin reduction to protect the electronic components and smoothly control the projectile posture. The complete guided projectile motion in the bore was reproduced by LS-DYNA software, where the gunpowder pressure was loaded on the projectile bottom. The dynamic parameters of the projectile obtained by simulation agree well with the test, including the axial velocity, acceleration and rotation speed. Great spin reduction occurs in the bore by the sliding belt assembly, which is indicated by the rotation speed and the motion of the sliding belt and projectile, respectively. From the interaction of the belt assembly at typical times, it is the escaping from the bases periodically of the belt ring so that greatly spin reduction of the projectile body is achieved.
Modeling and Simulation of Hydraulic Buffer in the Gatling Gun
Authors: Liu D , Wang ZX , Shen YL , Meng C , Zhang SM , Li Y
Published: May 2023

For the gatling weapon, due to its high firing rate and the complex characteristics of recoil, reducing the recoil resistance and enhancing firing precision becomes an important research topic for the improvement of the performance of gatling weapon system. In this paper, a spring-hydraulic floating buffer device was designed as the whole gun buffer. Based on the computational fluid dynamics numerical analysis method, a calculation model of the hydraulic buffer in the gun was established. ADAMS was used to simulate the buffer, and the recoil force of automata was obtained. By comparing the simulation results with the actual test results, the correctness of the calculation and simulation methods is verified, and a technical route combining simulation calculation and test is obtained, which lays a foundation for the practical engineering application and the hydraulic buffer design.
Study on Gliding Extended Range Ballistics of Long-Range Guided Mortar Projectiles
Authors: Shengzheng Chen , Yuhang Song , Boyi Kang , Qingshan Du
Published: May 2023

This paper endeavors to discuss the long-range guided mortar projectile scheme and the gliding extended range ballistics design. Starting from the glide extended range ballistic kinematics equation, analysis results show that the lift-drag ratio and the maximum ballistic height are the two most important factors affecting the gliding capability of guided mortar projectiles. This conclusion, verified by simulation analysis, is expected to provide certain guidance for the overall design of the long-range guided mortar munition.
Molecular dynamics simulation of the gun barrel material erosion by propellant gas
Authors: Dong X Q , Chen A
Published: May 2023

The mechanisms of propellant gas chemical erosion on gun barrel materials are discussed creatively from a microscopic perspective of molecular diffusion and intermolecular interaction. The influence of high-temperature and high-pressure propellant gas atoms on the shallow surface microstructure of the barrel material is theoretically analyzed using the molecular dynamics simulation method, which can be used as a new idea for further study of the gun barrel erosion mechanism. The results show that the diffusion of the propellant gas atoms into the barrel material can be characterized by the significant longitudinal distribution characteristics of propellant gas atoms and the normal stress distribution characteristics in the surface layer of the barrel. Moreover, the diffusion ability of the propellant gas atoms in the surface of the barrel material decreases gradually with the increasing diffusion depth. Under the action of propellant gas atoms, the dislocation structure dominated by face-centered cubic structure (FCC) forms in the shallow surface of the barrel material. The production of initial erosion in the shallow surface of barrel materials can be predicted by the continual growth of the new structure and the stress distribution characteristics of the material. In addition, the temperature variation of the propellant gas contributes significantly to barrel material erosion.
Research on optimization of aiming point of sub cluster anti-airport runway based on particle swarm optimization algorithm
Authors: Liu Yunhui , Zhu Peng , Yan Jundan , Zhang Wei , Ma Qingyue , Hu Longbing , Weixiang Zhang
Published: May 2023

A particle swarm optimization algorithm is proposed in this study to optimize the fire distribution, so as to solve the fire distribution problem of cluster warhead anti-airport runway. The particle swarm optimization fitness function is built based on the calculation model of cluster warhead anti-airport runway blocking probability using the Monte Carlo method, and the optimal cluster warhead aiming point allocation scheme is obtained using the particle swarm optimization algorithm. Moreover, the feasibility and advantages of the algorithm are compared and analyzed in the case of different size airports and different number of submunitions. The results provide a reference for the formulation of operational scheme when the cluster bomb strikes the airport runway.
Ballistic Simulation and Analysis of Turntable Rotation on the Flight Stability of Anti-aircraft Rocket
Authors: Jiang M , Zhang ZY , Li Y , Liu YW
Published: May 2023

The air defense multiple launch rocket is an effective terminal air defense weapon. The rotation of its turntable has an effect on the rocket’s ballistic. In the paper, the rotation angular velocity of the turntable is combined into the initial swing angular velocity of the transverse and longitudinal axis of the projectile axis. Based on this, taking the rotation of the turntable in the direction as an example, the six-degree-of-freedom rigid body ballistic model is selected for full ballistic simulation, and the stability of the projectile flight at different rotation angular velocities is studied according to the simulation results of the rocket attitude angle.
Research on Artillery Firing Trajectory under the Condition of Extra-large Elevation Difference between Artillery and Target in Plateau Area
Authors: Duan Yanan , Liu Yuwen , Cheng Yan , Jiang Ming , Zhang Zhiyuan
Published: May 2023

Get the influence of shooting on the ballistic elements and correction elements of grenade under the condition of extra-large elevation difference between artillery and target in plateau area through simulation, and drawn the comparison chart of different altitude and elevation difference between artillery and target by using the simulation data. Calculate the variation characteristics of the hit range of laser terminal guided projectile under the condition of the elevation difference of extra-large elevation difference between artillery and target at different altitudes, and the influence of altitude and extra-large elevation difference between artillery and target on the hit range of laser terminal guided projectile is analyzed and summarized. It has a certain reference value for improving the shooting accuracy under the condition of high altitude and extra-large elevation difference between artillery and target.
Study on Dynamic Pressure Control of Air-Breathing Hypersonic Vehicle
Authors: Ma Q H , Pan R , Li J P , Deng H P
Published: May 2023

To satisfy the strict requirements of dynamic pressure for air-breathing hypersonic vehicle during the initiation, a dynamic pressure control method based on the model reference sliding mode theory is designed. Firstly, the motion equation of the air-breathing hypersonic vehicle is built, and the dynamic pressure linearization model is established by the small perturbation method. Secondly, the control system, designed by the model reference sliding mode control theory, can quickly track the reference model. Finally, the six degrees of freedom simulation model is built and used for digital simulation. The simulation results show that the designed control system can accurately track the dynamic pressure command with great robustness.
Design of Long-Stroke ejector with Traveling Charge Structure
Authors: Jing Li , Chen Jin , Yang Zhao , Jia Zinian , Zhou Chuanxia , Liu Xinwei
Published: May 2023

Generally, the independently designed charge is used in traditional ejectors, where the gunpowder is usually fixed at its end. For long-stroke ejectors, the energy from gunpowder combustion in the later period of piston movement is mostly used for structure expansion, and only a small part is converted to piston actuation. The energy for piston movement can only be improved by increasing the amount of gunpowder, which results in large instantaneous pressure in the combustion chamber, thus leading to a big impact on the system structure by the pyrotechnic products. To deal with this problem, a design method for the long-stroke ejector based on traveling charge structure is proposed. It integrates the charge structure with piston design to ensure that the energy from gunpowder combustion can fully act on the bottom of the piston during the whole combustion process, thus improving the proportion of energy from gunpowder combustion transformed to the piston’s kinetic energy and reducing the charge quantity, which will then lessen the impact of pyrotechnic products on the system structure and improve its reliability. It has been experimentally proven that when designing a long-stroke ejector, the energy utilization rate of gunpowder can be increased by about 1.5 times by adopting the traveling charge structure compared to the traditional charge structure.