bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of risk factors associated with cerebral angiography headache
Authors: Madeira Tiago , Correa Amanda Viguini Tolentino , Abranches Gabriela de Paula , Masruha Marcelo Rodrigues
Published: May 2023

Background Despite previous studies indicating a moderate/high incidence of angiography headache (AH), there is still limited data about the risk factors associated with its occurrence.

Objective The present study aimed to assess the associations among demographic, clinical, and technical characteristics of cerebral digital subtraction angiography (DSA) and the occurrence of AH.

Methods Cross-sectional analytical observational study with a sample comprised of individuals with a recommendation for elective DSA. Clinical interviews were conducted to assess the occurrence of AH, using a standardized questionnaire.

Results Among 114 subjects, the mean age was 52.8 (±13.8) years old, 75.4% (86/114) were women, 29.8% (34/114) had a history of migraines, and 10.5% (12/114) had chronic headaches. The overall frequency of AH was 45.6% (52/114). Of those, 88.4% (46/52) underwent 3D angiography, 7.7% (4/52) underwent aortography, and 1.9% (1/52) underwent both procedures. There was a statistically significant association between AH and previous history of migraine (odds ratio [OR]: 4.9; 95% confidence interval [CI] 1.62–14.7; p = 0.005) and 3D angiography (OR 6.62; 95%CI: 2.04–21.5; p = 0.002).

Conclusions 3D angiography is strongly associated with the occurrence of AH, which has never been reported before. The association between a previous history of migraine and AH confirms the results of previous studies.
History and national survey on reflex hammers: which is the chosen one of Brazilian neurologists?
Authors: Disserol Caio César Diniz , Meira Alex Tiburtino , Schramm Carla Caroline , Kondo Gustavo Koiti , Franklin Gustavo Leite , Pedroso José Luiz , Barsottini Orlando Graziani Povoas , Teive Hélio Afonso Ghizoni
Published: May 2023

Background Percussion is an important part of the neurological examination and reflex hammers are necessary to obtain it properly.

Objective We aimed to review the historical aspects of the main reflex hammers and to define the favorite one of Brazilian neurologists.

Methods We searched original and review articles about historical aspects of the reflex hammers in Scielo and Pubmed and conducted an online survey to investigate the favorite reflex hammer of Brazilian neurologists.

Results In the first part, we describe the major milestones in the creation of the reflex hammers. Following, we exhibit the results of the online survey: Babinski-Rabiner was the most voted.

Conclusions The origins of the reflex hammers goes back long before their creation, from a basic clinical examination method: percussion. Since the description of deep tendon reflexes and the creation of percussion hammers, much has been improved in this technique. Among all the hammers surveyed, the Babinski-Rabiner was the chosen one by a significant portion of Brazilian neurologists.
Theoretical study on organic photovoltaic heterojunction FTAZ/IDCIC
Authors: Yang Bing , Zhang Cai-rong , Wang Yu , Zhang Mei-ling , Liu Zi-jiang , Wu You-zhi , Chen Hong-shan
Published: May 2023

Understanding organic photovoltaic (OPV) work principles and the materials’ optoelectronic properties is fundamental for developing novel heterojunction materials with the aim of improving power conversion efficiency (PCE) of organic solar cells. Here, in order to understand the PCE performance (>13%) of OPV device composed of the non-fullerene acceptor fusing naphtho[1,2-b:5,6-b′]dithiophene with two thieno[3,2-b]thiophene (IDCIC) and the polymer donor fluorobenzotriazole (FTAZ), with the aid of extensive quantum chemistry calculations, we investigated the geometries, molecular orbitals, excitations, electrostatic potentials, transferred charges and charge transfer distances of FTAZ, IDCIC and their complexes with face-on configurations, which was constructed as heterojunction interface model. The results indicate that, the prominent OPV performance of FTAZ:IDCIC heterojunction is caused by co-planarity between the donor and acceptor fragments in IDCIC, the the charge transfer (CT) and hybrid excitations of FTAZ and IDCIC, the complementary optical absorptions in visible region, and the large electrostatic potential difference between FTAZ and IDCIC. The electronic structures and excitations of FTAZ/IDCIC complexes suggest that exciton dissociation can fulfill through the decay of local excitation exciton in acceptor by means of hole transfer, which is quite different from the OPVs based on fullerenes acceptor. The rates of exciton dissociation, charge recombination and CT processes, which were evaluated by Marcus theory, support the efficient exciton dissociation that is also responsible for good photovoltaic performance.
Fabrication of Nb and MoGe SQUID-on-tip probes by magnetron sputtering
Authors: Romagnoli G. , Marchiori E. , Bagani K. , Poggio M.
Published: May 2023

We demonstrate the fabrication of scanning superconducting quantum interference devices (SQUIDs) on the apex of sharp quartz scanning probes—known as SQUID-on-tip probes—using conventional magnetron sputtering. We produce and characterize SQUID-on-tips made of both Nb and MoGe with effective diameters ranging from 50 to 80 nm, magnetic flux noise down to 300 nΦ0/Hz, and operating fields as high as 2.5 T. Compared to the SQUID-on-tip fabrication techniques used until now, including thermal evaporation and collimated sputtering, this simplified method facilitates experimentation with different materials, potentially expanding the functionality and operating conditions of these sensitive nanometer-scale scanning probes.
Theorizing sustainable, low-resource MT in development settings
Authors: Riemland Matt
Published: May 2023

This article conducts a meta-analysis of existing research to theorize how machine translation (MT) may help resolve underlying contradictions in the development sector that preclude the UN’s 10th Sustainable Development Goal: to reduce inequality within and among countries. Non-governmental organizations (NGOs) frequently work in dominant languages and neglect marginalized languages, reinforcing power imbalances between the Global North and Global South in development planning. MT between marginalized languages may improve collaboration between local communities to redress shared disadvantages. As an example, the article hypothesizes a sustainable, “low-tech” MT system pivoting through Spanish to translate between three Mayan languages in Guatemala: K’iche’, Q’eqchi’, and Mam. First, the article theorizes three key dimensions comprising the overall sustainability of low-resource MT in development: quality, social, and environmental. It then evaluates the sustainability of various MT architectures. Finally, it reaffirms the ability for indirect translation (classic pivot-based MT) to facilitate MT between low-resource languages.
Educational inclusion of students with type-1 diabetes. A systematized review (La inclusión educativa del alumnado con diabetes tipo 1. Una revisión sistematizada)
Authors: Cáceres-Iglesias Judith , Gajardo-Espinoza Katherine , Torrego-Egido Luis
Published: May 2023

Inclusive education is a recognized right. One of the factors addressed the least by the scholarly literature is the right to inclusive education among students with chronic diseases. Given the scarcity of research on this topic, the goal of this study is to identify and analyse how the research published has addressed the inclusion of students with diabetes. To meet this objective, we conducted a systematized literature review following some of the guidelines of the PRISMA statement. We searched in the databases Scopus and WOS and the Teseo, Dialnet and Google Scholar portals, where we found the 24 studies that comprise the data bank. The results show a reality that is a far cry from inclusive education, given that there are barriers like a lack of information and training, scant resources and support, no relations among the different administrations and the inexistence of public policies regulating attention to these students at school.
The relationship between auditory temporal processing, phonological processing and reading in Hong Kongese and Taiwanese children: from kindergarten to primary school (La relación entre el procesamiento temporal auditivo, el procesamiento fonológico y la lectura en los niños hongkoneses y taiwaneses: de preescolar a primaria)
Authors: Wang Li-Chih , Liu Duo , Yum Yen Na , Chung Kevin Kien-Hoa , Chu Szu-Yin , Tai Pui Lun Alan , Xu Zhengye , Kuo Hsu-Chan , Chang Chih-Ching
Published: May 2023

This study aims to compare auditory temporal processing and phonological processing across locations and age levels and to test the direct and indirect effects of auditory temporal and phonological processing on proficiency in Chinese character reading. We recruited 108 typically developing children — 25 and 24 kindergarteners from Taiwan and Hong Kong, respectively, and 34 and 25 primary school students from Taiwan and Hong Kong, respectively. Our findings showed that, before learning PCS, the languages’ phonological complexity did not affect the importance of ATP in Chinese reading. Also, we found the use of PCS could lead to a direct effect from students’ ATP to Chinese character reading as well as through phonological awareness. Our findings indicated that ways of learning to read influence children’s patterns of cognitive and linguistic abilities, which should be considered in teaching designs for reading.
A regression model for plasma reaction kinetics
Authors: Hanicinec Martin , Mohr Sebastian , Tennyson Jonathan
Published: May 2023

Machine learning (ML) is used to provide reactions rates appropriate for models of low temperature plasmas with a focus on A + B

→

C + D binary chemical reactions. The regression model is trained on data extracted from the QBD, KIDA, NFRI and UfDA databases. The regression model used a variety of data on the reactant and product species, some of which also had to be estimated using ML. The final model is a voting regressor comprising three distinct optimized regression models: a support vector regressor, random forest regressor and a gradient-boosted trees regressor model; this model is made freely available via a GitHub repository. As a sample use case, the ML results are used to augment the chemistry of a BCl3/H2 gas mixture.
A critical review on orthosilicate Li2MSiO4 (M = Fe, Mn) electrode materials for Li ion batteries
Authors: Pateriya Ravi Vikash , Tanwar Shweta , Sharma A L
Published: May 2023

The development of novel electrode materials with good electrochemical performances is necessary for the expanded and varied applications of lithium-ion batteries, and this development heavily relies on cathode materials. Due to excellent thermal stability, abundance, low cost, and environmental friendliness, orthosilicate cathode materials Li2MSiO4 (M = Fe, Mn) has received a lot of attention recently. The present review article gives a glimpse into the characteristics, advantages, and recent progress of orthosilicate cathode materials. This review starts with a brief history and working mechanism of batteries, the advantages of cathode materials followed by types of cathode materials, various synthesis methods, and different techniques used for their characterization. The most current initiatives to enhance orthosilicate Li2MSiO4 type electrochemical performances were introduced in this review. We provide a critical assessment of the efficient modification techniques for the orthosilicate Li2MSiO4 type cathode materials in particular. These potential cathode materials’ synthesis, structure, morphologies, and particularly electrochemical performances have been thoroughly examined. This evaluation, we hope, will clarify the sustained advancement of high-efficiency and reasonably priced Li-ion batteries.
Combined impacts of low oscillating magnetic field and Shliomis theory on mono and hybrid nanofluid flows with nonlinear thermal radiation
Authors: Alharbi Khalid Abdulkhaliq M , Shahmir Nazia , Ramzan Muhammad , Kadry Seifedine , Saeed Abdulkafi Mohammed
Published: May 2023

Hybrid nanofluids have become a popular choice for various engineering and industrial applications due to their advanced properties. This study focuses on investigating the consequences of a low oscillating magnetic field on the flow of unsteady mono and hybrid nanofluids over a vertically moving permeable disk. Initially, iron oxide nanoparticles are mixed with water to create a mono nanofluid, which is later transformed into a hybrid nanofluid by adding cobalt nanoparticles. The shape of nanoparticles used is brick-shaped, and an external magnetic field is applied to regulate the flow and heat transfer mechanism using ferromagnetic nanoparticles. Additionally, the nonlinear thermal radiative heat flux is considered for the heat transfer phenomenon. The momentum and rotational motion of the magnetic fluid caused by the rotating disk are formulated using the Shliomis fundamental concept. The numerical analysis of the ordinary differential equations (ODEs) is carried out using the bvp4c technique, and the results are presented in tabular form for the surface drag coefficient and heat transmission at the walls. Moreover, the temperature and velocity distributions are illustrated using graphical representations against relevant parameters. The findings highlight that for a constant negative value for the magnetization parameter

ϒ
<
0

,

the heat transfer rate for hybrid nanofluid is witnessed stronger at a volume fraction

ϕ

h
n
f

=
0.120

,

whereas a minimal heat transfer rate is observed for positive values of magnetization parameter

ϒ
>
0

at the same value of volume fraction.
Teaching large angle pendulum via Arduino based STEM education material
Authors: Erol Mustafa , Oğur Mehmet
Published: May 2023

This study reports an Arduino based STEM education material that resolves large angle pendulum, alternatively anharmonic oscillator, both experimentally and theoretically, particularly focuses on the time dependence of the instantaneous displacement angles. Instantaneous time dependence of the angles is experimentally measured by using Arduino Nano microprocessor connected to a gyro sensor and a bluetooth transmitter/receiver structured as a STEM education material. Theoretical resolution of the large angle pendulum is also accomplished by considering the approximate solution taking into account the relevant frictional effects. The theoretical and experimental resolutions are managed for the initial angles of

θ
0

=
1.40

 

rad

and

θ
0

=
2.61

 

rad

, specifically focusing on the angular frequencies, frictional effects and anharmonicity of the motion. The relative errors concerning the angular frequency are found to be % 15.2 and % 6.5 for

θ
0

=
2.61

 

rad

and

θ
0

=
1.40

 

rad

, respectively. The exponential decrease due to the frictional effects are in perfect agreement with each other and providing a friction coefficient of

γ
=
0.015

kg m

s

−
1

for both experimental and theoretical results. The anharmonicity of the pendulum is also illustrated by comparing the experimental plots and relevant theoretical plots for the small angle approximations. This work offers a prototype teaching material which can create an education environment where students can feel dynamic and encompass the acquisitions of Science Technology Engineering and Mathematics.
A graphical user interface for calculating the arterial input function during dynamic positron emission tomography
Authors: Daoud Youstina , Carroll Liam , Enger Shirin A
Published: May 2023

Purpose. Dynamic positron emission tomography (dPET) requires the acquisition of the arterial input function (AIF), conventionally obtained via invasive arterial blood sampling. To obtain the AIF non-invasively, our group developed and combined two novel solutions consisting of (1) a detector, placed on a patient’s wrist during the PET scans to measure the radiation leaving the wrist and (2) a Geant4-based Monte Carlo simulation software. The simulations require patient-specific wrist geometry. The aim of this study was to develop a graphical user interface (GUI) allowing the user to import 2D ultrasound scans of a patient’s wrist, and measure the wrist features needed to calculate the AIF. Methods. The GUI elements were implemented using Qt5 and VTK-8.2.0. The user imports a patient’s wrist ultrasound scans, measures the radial artery and veins’ surface and depth to model a wrist phantom, then specifies the radioactive source used during the dPET scan. The phantom, the source, and the number of decay events are imported into the Geant4-based Monte Carlo software to run a simulation. In this study, 100 million decays of 18F and 68Ga were simulated in a wrist phantom designed based on an ultrasound scan. The detector’s efficiency was calculated and the results were analyzed using a clinical data processing algorithm developed in a previous study. Results. The detector’s total efficiency decreased by 3.5% for 18F and by 51.7% for 68Ga when using a phantom based on ultrasound scans compared to a generic wrist phantom. Similarly, the data processing algorithm’s accuracy decreased when using the patient-specific phantom, giving errors greater than 1.0% for both radioisotopes. Conclusions. This toolkit enables the user to run Geant4-based Monte Carlo simulations for dPET detector development applications using a patient-specific wrist phantom. Leading to a more precise simulation of the developed detector during dPET and the calculation of a personalized AIF.
Evaluation of a modular all-in-one high-resolution PET detector and readout electronics setup
Authors: Schmidt F P , Krämer J C , Parl C , Schmand M , Pichler B J
Published: May 2023

Objective. The all-in-one solution and modularity of the C13500 series TOF-PET detector modules (Hamamatsu Photonics K.K., Hamamatsu, Japan) make them a highly attractive candidate for the development of positron emission tomography (PET) systems. However, the commercially available portfolio targets clinical whole-body PET systems with a scintillation crystal cross area of 3.1 × 3.1 mm2. To extend the modules for high resolution (preclinical or organ specific) systems, the support for smaller scintillation crystals is required. Approach. In this work, a PET detector was developed based on the TOF-PET modules using a light sharing approach, 16 × 16 lutetium oxyorthosilicate (LSO) scintillation crystals with a size of 1.51 × 1.51 × 10.00 mm3 readout with 8 × 8 photosensor channels of size 3.0 × 3.0 mm2. In addition to hardware and software development, the optimized parameter settings for the adapted configuration were evaluated. Main Results. A factor of two in amplification of the analog signal compared to the minimum gain setting was necessary for an accurate crystal identification (peak-to-valley ratio 14.9 ± 5.9). A further increase to a factor of three was not determined as optimum as the time over threshold duration, thus pile-up probability, increased from 1032.1 ± 109.5 to 1789.5 ± 218.5 ns (photopeak position). With this amplification a full width at half maximum (FWHM) energy resolution of 14.1 ± 2.0% and a high linearity of the energy detection was obtained. A FWHM coincidence resolving time (CRT) of 313 ps was achieved by using a low timing threshold, increasing the bandwidth of the front-end circuit and using a narrow ± 1σ energy window. To approximately double the sensitivity and reduce the power consumption, the timing parameters were adjusted resulting in a FWHM CRT of 354 ps (±2σ). Significance. Based on the results obtained with the proof-of-concept detector setup, we confirm the modularity and flexibility of the all-in-one TOF-PET detector modules for the future development of application-specific high-resolution PET systems.
Evaporation behavior of liquid microdroplets in atmospheric-pressure nonequilibrium plasma
Authors: Nitta Kaishu , Muneoka Hitoshi , Shimizu Yoshiki , Kobayashi Hiromichi , Terashima Kazuo , Ito Tsuyohito
Published: May 2023

In recent years, atmospheric-pressure nonequilibrium plasma processing using microdroplets has attracted significant attention. To improve the controllability of this process, an understanding of the evaporation behavior of droplets in plasma is highly desirable. In this study, we examine the evaporation behavior of well-controlled inkjet droplets in atmospheric-pressure nonequilibrium argon plasma through both experiments and modeling. A comparison of the droplet evaporation model based on energy balance considering gas temperature, electron and ion collisions, and recombination reactions with experimental evaporation behavior suggests that droplet evaporation is enhanced in high-density plasma environments with electron and ion densities exceeding 1019 m−3 when compared with that in non-ionized gaseous environments at a gas temperature below 1000 K.
Sub-bandgap photon-assisted electron trapping and detrapping in AlGaN/GaN heterostructure field-effect transistors
Authors: Gunn Andrew W , Prio Makhluk Hossain , Gajula Durga , Koley Goutam
Published: May 2023

We have investigated photon-assisted trapping and detrapping of electrons injected from the gate under negative bias in a heterostructure field-effect transistor (HFET). The electron injection rate from the gate was found to be dramatically affected by sub-bandgap laser illumination. The trapped electrons reduced the two-dimensional electron gas (2DEG) density at the AlGaN/GaN heterointerface but could also be emitted from their trap states by sub-bandgap photons, leading to a recovery of 2DEG density. The trapping and detrapping dynamics were found to be strongly dependent on the wavelength and focal position of the laser, as well as the gate bias stress time prior to illumination of the HFET. Applying this phenomenon of trapping and detrapping assisted by sub-bandgap photons, red, green, and purple lasers were used to demonstrate photo-assisted dynamic switching operations by manipulation of trapped carriers at the surface of an AlGaN/GaN HFET. A physical model based on band diagrams, explaining the trapping and detrapping behavior of electrons, has been presented.
Effect of bubbles at the bonded interface on the performance of GeSn/Si PIN photodetector
Authors: Chai Jianfei , Ke Shaoying , Huang Yuan , Tan Chuhui , Wang Rongfei , Yang Jie , Wang Chong
Published: May 2023

Due to the large lattice mismatch between GeSn and Si materials, high-density threading dislocation (TD) forms when GeSn films are grown by epitaxial growth. This leads to the increase of the dark current density (DCD) of the device. The wafer-bonded technique is a promising method to prepare high-quality thin films. This has been used to produce the Si-based GeSn materials with low TDD. However, there are a lot of bubbles at the bonded interface, resulting in the deterioration of the performance of the device. The study of bubbles on the performance of the GeSn PIN photodetector (PD) has not been reported. In this paper, the effects of the bonding bubbles on the performance of the device are performed. The photocurrent, dark current, charge concentration, electric field, and 3dB-bandwidth (BW) as a function of the bubble radius and thickness are demonstrated. The effects of the bubble radius and thickness on the 3dB-BW (∼18 GHz) are insignificant when the bubble thickness and radius are set as 1 nm and 1 μm, respectively. The 3dB-BW decreases to ∼17 GHz when the bubbles are close to the sizes of the top mesa. However, the 3dB-BW drops drastically with the increase of the bubble thickness when the bubble radius reaches 7 μm. Most importantly, the 3dB-BW sharply decreases to ∼30 MHz regardless of the thickness of the bubble when the bubble radius of 14 μm is set. This may provide guidance for the application of the wafer-bonded GeSn PIN PD.
Enhanced NIR fluorescence quantum yield of graphene quantum dots using dopants
Authors: Rani Priya , Dalal Ranjeet , Srivastava Sunita
Published: May 2023

In the present work, several efforts have been made theoretically to achieve an excellent non-toxic fluorescent graphene quantum dot (GQD) in the near-infrared region for the application of bio-imaging and sensing. Although the QY of GQDs is a maximum of 98.5% in the visible region, it is still very low, and it is as low as 7% in NIR. Sulfur and its group elements have been used for doping because they are pretty cheap and nontoxic and hence suitable for this application. The surface-doped position is considered for studying their effect on the energy band gap, absorption and fluorescence properties. The HOMO and LUMO isosurfaces have been analyzed in order to comprehend the nature of the dominant transition taking place in absorption spectra. Additionally, the quantitative indices, transition density matrix contour maps, and charge difference density have all been examined in order to determine whether this particular transition is locally excited or involves charge transfer. Following this, the QY of each GQD has been determined by considering the fluorescence spectra. The wavelength of fluorescence of doped GQDs is found to be in the region of 800–1400 nm, i.e. in NIR, which is strongly desirable for bio-imaging and bio-sensing applications. With a fluorescence of ∼850 nm, sulfur-doped GQDs (S-GQD: C52S2H18) have the greatest QY, 26%, which is larger than the 7% achieved earlier in NIR and such a high QY in NIR is being reported for the first time.
Nanoscale spectroscopic mapping by scanning probe electron energy spectroscopy
Authors: Li Zhongfeng , Xu Chunkai , Li Zhean , Huang Wei , Chen Xiangjun
Published: May 2023

Scanning probe electron energy spectroscopy (SPEES) is a developing technique capable of both topographic and spectroscopic mapping of the surface. Here we report a SPEES study for Ag nanostructures on graphite with a microelectrode-shielding tip. The spatial distributions of electron energy loss spectra as well as secondary-electron emission spectra in the same region on the surface are measured. The spatial resolution is determined to be about 17 nm. This demonstrates the nanoscale spectroscopic mapping ability of the SPEES and a promising tool for investigating highly-localized object on surface and related phenomena, such as plasmonic substrates, nonlinear electron scattering, etc.
Inatorial forecasting method considering macro and micro characteristics of chaotic traffic flow
Authors: Hou 侯 Yue 越 , Zhang 张 Di 迪 , Li 李 Da 达 , Yang 杨 Ping 萍
Published: May 2023

Traffic flow prediction is an effective strategy to assess traffic conditions and alleviate traffic congestion. Influenced by external non-stationary factors and road network structure, traffic flow sequences have macro spatiotemporal characteristics and micro chaotic characteristics. The key to improving the model prediction accuracy is to fully extract the macro and micro characteristics of traffic flow time sequences. However, traditional prediction model by only considers time features of traffic data, ignoring spatial characteristics and nonlinear characteristics of the data itself, resulting in poor model prediction performance. In view of this, this research proposes an intelligent combination prediction model taking into account the macro and micro features of chaotic traffic data. Firstly, to address the problem of time-consuming and inefficient multivariate phase space reconstruction by iterating nodes one by one, an improved multivariate phase space reconstruction method is proposed by filtering global representative nodes to effectively realize the high-dimensional mapping of chaotic traffic flow. Secondly, to address the problem that the traditional combinatorial model is difficult to adequately learn the macro and micro characteristics of chaotic traffic data, a combination of convolutional neural network (CNN) and convolutional long short-term memory (ConvLSTM) is utilized for capturing nonlinear features of traffic flow more comprehensively. Finally, to overcome the challenge that the combined model performance degrades due to subjective empirical determined network parameters, an improved lightweight particle swarm is proposed for improving prediction accuracy by optimizing model hyperparameters. In this paper, two highway datasets collected by the Caltrans Performance Measurement System (PeMS) are taken as the research objects, and the experimental results from multiple perspectives show that the comprehensive performance of the method proposed in this research is superior to those of the prevalent methods.
Sustained and potent analgesia with negligible side effects enabled by adaptive individualized granular stimulation in rat brainstem
Authors: Forni Matilde , Thorbergsson Palmi Thor , Gällentoft Lina , Thelin Jonas , Schouenborg Jens
Published: May 2023

Objectives. To clarify if an adaptive current stimulation protocol, in which current amplitude is modulated during continuous stimulation, provides better efficacy than constant current stimulation protocol with respect to analgesia caused by individualized stimulation in rat periaqueductal gray matter (PAG) /dorsal raphe nuclei (DRN). Approach. Ultrathin microelectrodes adapted for recording (n = 6) and stimulation (n = 16) were implanted in rat primary somatosensory cortex and PAG/DRN, respectively. In each animal included (n = 12), a subset of PAG/DRN microelectrodes (n = 1–3 per animal) was selected that on simultaneous stimulation blocked nociceptive withdrawal reflexes in awake unrestrained animals without noticeable side effects. Analgesic effects were subsequently assessed from both nociceptive withdrawal reflexes and intracortical pain-related responses on CO2 laser hind paw stimulation. The analgesic effects of adaptive current PAG/DRN stimulation comprising incremental increases of 5 μA/microelectrode (initial median current 30 μA/microelectrode) when effects declined were compared to the effects of constant current stimulation. Behavioral effects and brain state related changes were analyzed using quantitative movement analysis and electrocorticography (recorded on top of the dura mater), respectively. Tissue reactions and probe placement in PAG/DRN were assessed with immunohistochemistry. Main results. Powerful and sustained (4 h) analgesia was achieved with the adaptive current protocol within a rather wide area of PAG/DRN. Analgesic after-effects were seen for up to 30 min. Behavioral and brain state related side effects were minimal. Moreover, 6 weeks after implantation, there were no traces of bleedings, only small glial reactions and small but not statistically significant loss of neurons nearby indicating that the microelectrode stimulation employed is biocompatible. Significance. The results indicate that sustained and powerful analgesia with minimal side effects can be achieved by granular and individualized stimulation in PAG/DRN using an adaptive current stimulation protocol. This microelectrode technology and stimulation paradigm thus has the potential of providing a highly efficient and safe pain therapy.
Investigating the impact of the molecular charge-exchange rate on detached SOLPS-ITER simulations
Authors: Verhaegh K. , Williams A.C. , Moulton D. , Lipschultz B. , Duval B.P. , Février O. , Fil A. , Harrison J. , Osborne N. , Reimerdes H. , Theiler C. , the TCV Team
Published: May 2023

Plasma-molecular interactions generate molecular ions which react with the plasma and contribute to detachment through molecular activated recombination (MAR), reducing the ion target flux, and molecular activated dissociation (MAD), both of which create excited atoms. Hydrogenic emission from these atoms has been detected experimentally in detached TCV, JET and MAST-U deuterium plasmas. The TCV findings, however, were in disagreement with SOLPS-ITER simulations for deuterium, indicating a molecular ion density (D2+) that was insufficient to lead to significant hydrogenic emission, which was attributed to underestimates of the molecular charge exchange rate (D2+D+→D2++D) for deuterium (obtained by rescaling the hydrogen rates by their isotope mass). In this work, we have performed new SOLPS-ITER simulations with the default rate setup and a modified rate setup where ion isotope mass rescaling was disabled. This increased theD2+content by>×100. By disabling ion isotope mass rescaling: (1) the total ion sinks are more than doubled due to the inclusion of MAR; (2) the additional MAR causes the ion target flux to roll-over during detachment; (3) the totalDαemission in the divertor increases during deep detachment by roughly a factor of four; (4) the neutral atom density in the divertor is doubled due to MAD, leading to a 50% increase in neutral pressure; (5) total hydrogenic power loss is increased by up to 60% due to MAD. These differences result in an improved agreement between the experiment and the simulations in terms of spectroscopic measurements, ion source/sink inferences and the occurrence of an ion target flux roll-over. Extrapolating simplified scalings of divertor molecular densities (TCV & MAST-U) to reactor-relevant densities suggests the underestimation of molecular charge exchange could strongly impact divertor physics (neutral atom density, ions sinks) and hydrogen emission (which has implications for detachment control) in deeply detached conditions, warranting further study.
Analysis of influencing factors of projectile velocity in low-speed sub-caliber launch
Authors: Zhang B , Peng G , Feng JC , Wang XC , Wang W , Chen CX , Gao B
Published: May 2023

In the ballistic performance testing field of human body protection and armor protection, aiming at the demand of sub-caliber launch of assembled ammunition with the mass range of 4 ~ 16 g and velocity range of 280 ~ 500 m/s, establish the mathematical model of interior ballistic with MATLAB, calculate the interior ballistic state, and analyze the influence law of the change of charge parameters and projectile mass with the launch velocity. The results show that the propellant does not burn completely as the small-mass projectile leaves the barrel; under the same chamber volume, the projectile velocity increases with the charge mass, and this trend gradually decrease with the increasing chamber volume; under the same charge mass, the projectile velocity decreases with the increase of chamber volume, and this trend gradually increases with the increasing charge mass; under the same projectile mass, the projectile velocity decreases with the increase of charge mass, and this trend remains basically unchanged as the projectile mass increases. The analysis and calculation results are verified by the firing test. The results show that although there are differences between the actual charge quality and the calculation results, the obtained velocity changing trend is basically consistent with the trend revealed by the calculation results. The analysis and verification results can provide guidance for understanding the influencing factors affecting the launch of sub-caliber low-speed projectile, and have positive significance for improving the ballistic performance testing ability and promoting the development of the protection industry.
Base-backstepping Continuous Time-varying Feedback Control of Automatic Magazine with Modelling Uncertainty
Authors: Lin Y B , Hou B L
Published: May 2023

This paper proposes a continuous time-varying feedback control based on back-stepping for automatic magazine system, in which the control gains depend on the Lyapunov function to ensure the robustness against modelling uncertainty. The Lyapunov function, which is implicit, is differentiable functions of system error variables. Integrated with backstepping control, the performance of the automation magazine system is greatly improved, while retaining the advantage of only needing to ensure the bounds of disturbances. Lyapunov analysis shows tracking errors of the system are asymptotically stable. In addition, this proposed controller is continuous and has the characteristics of simplicity and practicality, which are beneficial to practical applications. Finally, Numerical simulations are provided to verify the high performance of the controller by comparing the simulation experimental results in automation magazine system.
Structural Parameters Optimal Design of the Upper Carriage Structural of a Truck-mounted Howitzer Under Multiple Working Conditions
Authors: Mao ZZ , Xu YD , Jia ZY
Published: May 2023

In order to reduce the force transmitted from the upper carriage of a Truck-mounted howitzer to the lower carriage, the upper carriage is optimized for structural parameters under the premise that the position of the trunnion chamber is allowed to change. Based on the secondary development function of ABAQUS, established the parametric modeling script of the upper carriage structural, and built the ABAQUS computing environment through the integration of Simcode components of the ISIGHT platform. The position parameters of the trunnion chamber on the upper carriage were selected as the design variables, and the maximum support reaction force was minimized as the optimization objective. The multi-island genetic algorithm was used to optimize the structure parameters of the upper carriage under multiple working conditions, and the global optimal solution was obtained. The optimization results meet the rigidity and strength requirements, and the optimization effect is obvious. This optimization method can be used in the design of the upper carriage structure, reducing the force transmitted from the upper carriage of the artillery to the lower carriage, and can provide a certain optimization space for the weight reduction of the lower carriage, and has engineering application value.
Application of Fuzzy Adaptive Control in Gun Servo System
Authors: Dai P , Han C W , Kong R Y , Zhang G S , Liu M
Published: May 2023

Friction torque is an important parameter affecting the servo system, which will decrease with the increase of service time. With the change of friction torque, the control characteristics of the servo system will change, resulting in the servo dynamic and static performance can not meet the system requirements. On the basis of expounding the composition and working principle of gun pitching servo system, a control method of gun servo system based on fuzzy adaptive control is proposed. The problem of system performance change caused by the change of servo system parameters is solved. Through MATLAB simulation, it shows that the method can eliminate the influence of friction torque change on the system, make the system insensitive to the change of torque parameters, and meet the use requirements under various parameter conditions.
Research on Performance Improvement of Projectile Velocity Measurement Model
Authors: Li Hai , Ni Jinping , Chen Ding
Published: May 2023

This paper studies the existing photoelectric velocimetry model, which assumes that the trajectory is straight and the projectile velocity is uniform and constant in the test area. In the test of muzzle velocity of projectile and the experiment of miss distance of proximity fuze, the influence of air resistance and other factors on the velocity during the flight of projectile is not considered, so there is a big test error in the velocity value. In this paper, an optimized test method of velocity parameters is put forward by deeply studying the aerodynamics of projectile in flight and combining with physical mechanics. Through experiments and simulation studies, it can be proved that the speed parameter value determined by this method is closer to the true value, and the relative error is much smaller than the existing measurement methods, which has certain practical value in practice.
Research on the damage effectiveness of AHEAD against the LSS UAV clusters
Authors: Fan Ji , Tang Xu , Wang Baohua , Shu Lipeng , Lu Yin , Chen Xiaoming
Published: May 2023

With the expansion of unmanned aerial vehicle(UAV) applications and increased power, the status of unmanned aerial vehicles in the military field has continued to improve. How to effectively defend against UAV attacks has become a key research issue in various countries. The damage assessment model of the AHEAD in the literature [17] does not consider the systematical error of anti-aircraft artillery, and ignores the dispersion error of the AHEAD explosion-points in the direction of the vertical interception plane, which leads to the inaccuracy of the calculated damage probability. In this paper, the model is modified, the systematical error and the dispersion error of the opening point in the direction of the vertical interception plane are added to the original model, and then the improved model is used to analyze the damage effectiveness of the AHEAD against two typical LSS UAVs. It shows that the AHEAD has good damage efficiency to LSS UAVs. To a certain extent, it has the ability to counter the LSS UAV clusters.
Analysis of Muzzle Flow Field Characteristic of Machine Gun in Different Environments
Authors: Zhang X , Zhang X W
Published: May 2023

To study the distribution characteristics of the muzzle flow field of the underwater sealed launch in different environments, a two-dimensional axisymmetric multiphase flow numerical model was established. The VOF multiphase flow model, Standard k-ε turbulence model, user-defined function (UDF), and dynamic mesh technology are used to simulate the evolution process of the muzzle flow field of underwater sealed launch and air launch. The calculation results show that the muzzle flow field of the underwater sealed launch is significantly different from that in air. The initial velocity of the projectile for underwater sealed launch is 64 m/s, lower than that in air, while the muzzle pressure and temperature are significantly increased. The Mach disk is initially formed at about 145μs for launched underwater, while it is about 240μs for air launch. When launching underwater, the velocity of the projectile is linear attenuation after it leaves the muzzle, while the projectile first accelerates and then slowly decays launched in air. Compared with launching in air, the core area of the shock wave launched underwater is smaller, the pressure at the warhead is relatively higher, and there is no crown shock wave in front of the projectile head.
Analysis and Optimization Design of Gunpowder Gas Sealing Performance of a Revolving Chamber Automatic Mechanism
Authors: Gu B , Ye KW , Liu PK , Ning BF
Published: May 2023

When the revolving chamber automatic mechanism fires, it is required to reserve a gap between the revolving chamber bushing and its bushing hole to move back and forth to realize the gunpowder gas sealing performance between the barrel bushing and the revolving chamber bushing. Its gas leakage failure modes mainly include the radial gap gas leakage between the revolving chamber bushing and its bushing hole as well as the transverse gap gas leakage between the end surfaces of the two bushings. Aiming at the two typical gas leakage failure modes, the analysis models of the revolving chamber bushing radial clearance and the transverse clearance of the end surfaces of the two bushings are established respectively. Combining with the load such as chamber pressure, the gas sealing performance is analyzed, the effects of unilateral clearance, groove and pushing force acting outer diameter on the gas sealing performance are analyzed, and the optimal design scheme of the gas sealing performance is put forward. Taking the maximum instantaneous flow as the evaluation index, the gas sealing performance of the revolving chamber automatic mechanism is improved by more than 30%. The research has important reference value for the design of gas sealing structure of revolving chamber gun.
The simulation of the rigid-flexible coupling model of the tank firing on the move based on fully flexible body modeling method
Authors: Liu J , Zhang C , Zhou F M
Published: May 2023

Generally, the rigid-flexible coupling model based on the modal reduction method cannot realize the contact between the rigid body and the flexible body. Based on the multi-body systems dynamics and fully flexible body modeling method, the rigid-flexible coupling dynamics model of the tank gun system was constructed. Then by combining with the PID control model, the mechanical/control co-simulation model of the tank gun on the move was constructed. The influences of the control system and vehicle speed on the muzzle vibration during the shooting process were respectively analyzed. It has been shown that the control system model can effectively simulate the response characteristics of the muzzle during the move of the tank. Under the same road surface and the same control law, the frequency and amplitude of the muzzle angular displacement in the low frequency range increase with the increase of the vehicle speed. The constructed model and the simulation results are of great significance to the analysis and optimization of the shooting accuracy of the tank gun on the move.
Parameter estimation of the shell transfer arm of a loading mechanism
Authors: Zhou S J , Chen G S , Gao X K
Published: May 2023

The shell transfer arm is a key component of gun automatic loading mechanism, the coordination speed and positioning accuracy have an important impact on gun ammunition delivery effect. Establishing an accurate dynamic model is the foundation for better control and prediction, therefore, it is necessary to identify the dynamic parameters of the shell transfer arm. In this paper, the dynamic model is established based on the topology method. The parameter identification model of the shell transfer arm is constructed by applying the dynamic model and unscented Kalman filter theory. Dynamic parameters of the shell transfer arm such as the mass, inertia and centroid position are estimated under unscented Kalman filter scheme. By comparing the parameter estimation results with the nominal design values, the feasibility and effectiveness of applying the proposed method to identify the dynamic parameters of the shell transfer arm are verified.
A review of stability control algorithms for weapon platforms
Authors: Li Y X , Xu H B , Gu G X , Guo Y J , Wang B
Published: May 2023

Weapon platforms are considered to be one of the important preconditions that ensure modern weapon systems achieve expected functions, while the critical factor affecting platform stability is control algorithms. Firstly, this paper introduces the importance of weapon platforms and their control algorithms, and classifies conventional weapon platforms. Secondly, after analyzing the application of conventional and modern control algorithms in different weapon platforms, this paper presents the new development trends of weapon platform control algorithms, with the goal of providing some ideas for the development of weapon systems and weapon platforms in China.
Analytical Study on the Trajectory of a Projectile Motion with the Quadratic Resistant Law
Authors: Ding T B , Lin Z W , Wang G , He Z
Published: May 2023

In this paper, the trajectory of a projectile in a resistant medium with quadratic resistant law is investigated. Based on the elementary analysis method, the equation for the trajectory in Cartesian coordinates system is derived. By retaining the first order derivative of the slope of the trajectory, the trajectory equation is integrated by two different schemes, the Riccati eqation expansion method and the exp-function method. The solutions obtained in this paper present new viewpoint for future investigations on the traditional mechanical problem.