bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of α enhancement on the asteroseismic age determination of field stars
Authors: Valle G. , Dell’Omodarme M. , Prada Moroni P. G. , Degl’Innocenti S.
Published: March 2024

Aims. We investigated the theoretical biases affecting the asteroseismic grid-based estimates of stellar mass, radius, and age in the presence of a mismatch between the heavy element mixture of observed stars and stellar models.

Methods. We performed a controlled simulation adopting a stellar effective temperature, [Fe/H], an average large frequency spacing, and a frequency of maximum oscillation power as observational constraints. Synthetic stars were sampled from grids of stellar models computed with different [α/Fe] values from 0.0 to 0.4. The mass, radius, and age of these objects were then estimated by adopting a grid of models with a fixed [α/Fe] value of 0.0. The experiment was repeated assuming different sets of observational uncertainties. In the reference scenario, we adopted an uncertainty of 1.5% in seismic parameters, 50 K in effective temperature, and 0.05 dex in [Fe/H]. A higher uncertainty in the atmospheric constraints was also adopted in order to explore the impact on the precision of the observations of the estimated stellar parameters.

Results. Our Monte Carlo experiment showed that estimated parameters are biased up to 3% in mass, 1.5% in radius, and 4% in age when the reference uncertainty scenario was adopted. These values correspond to 45%, 48%, and 16% of the estimated uncertainty in the stellar parameters. These non-negligible biases in mass and radius disappear when adopting larger observational uncertainties because of the possibility of the fitting algorithm exploring a wider range of possible solutions. However, in this scenario, the age is significantly biased by −8%. Finally, we verified that the stellar mass, radius, and age can be estimated with a high accuracy by adopting a grid with the incorrect value of [α/Fe] if the metallicity [Fe/H] of the target is adjusted to match the Z in the fitting grid. In this scenario, the maximum bias in the age was reduced to 1.5%.
The nature of the X-ray filaments around bow shock pulsar wind nebulae
Authors: Olmi Barbara , Amato Elena , Bandiera Rino , Blasi Pasquale
Published: March 2024

Context. We propose that the X-ray filaments emerging from selected bow shock pulsar wind nebulae are due to a charge-separated outflow of electrons and/or positrons escaping the nebula and propagating along the local Galactic magnetic field.

Aims. The X-ray brightness, length, and thickness of filaments are all accounted for if a nonresonant streaming instability is excited.

Methods. This is possible if particles are released in the interstellar medium as a collimated beam, as would be expected in a reconnection region between the nebular and interstellar magnetic fields.

Results. We successfully test this idea on the Guitar Nebula filament and discuss other cases.

Conclusions. These filaments provide the best diagnostics available for particle escape from evolved pulsar wind nebulae, a process essential to assessing the contribution of these sources to cosmic ray positrons. The same phenomenology might govern the occurrence of TeV halos and their importance for cosmic ray transport.
Analysing the chemical standards of the Fergana Mekhmash wastewater treatment plant and environmental processing
Authors: Mirsaidov Makhmudjon , Nimchik Alexey , Khodjiyev Oybek , Jesfar Mohamed , Zokirov Kurbonalijon , Shamatov Sirojiddin , Toshpulatov Khurshidjon , Kambarov Asadjon
Published: March 2024

Protection of the environment from pollution and rational use of natural resources is one of the main problems of the present time. Saving and protecting water resources is the solution to this problem. Wastewater (dirty water from industrial and domestic enterprises) and stormwater treatment are an important part of nature protection. This article is the study of the technology of industrial wastewater treatment and the composition of dry residues left after water treatment from the galvanic department of the MexMash plant in the city of Fergana. Redirection of ZnO, Fe2O3, FeO and P2O5 contained in waste, application of ecological treatment of wastewater. In the industrial production enterprise of the city of Fergana, it was considered to study the composition of the waste produced as a result of the treatment of wastewater generated during the production process and to direct it to production.
Technology of pumping production of high-viscosity oil with injection of coolant to the bottom through hollow rods
Authors: Mingulov Shamil , Mukhametshin Vyacheslav V. , Kuleshova Lyubov , Gizzatullina Alina , Gilyazetdinov Ruslan
Published: March 2024

The purpose of the study is to develop a pumping unit that allows successful injection of coolant into the bottom of the well through a column of hollow rods, followed by oil extraction from the well without lifting equipment. The scientific novelty of the material is based on the possibility of heating the bottom-hole zone of the formation and simultaneous oil production. The technological process of extracting hard-to-recover oil using the proposed installation is based on the following operations: withdrawal of the intake into the annulus, descent of the pump shank into the horizontal shaft; steam injection to the shank and its movement within the bottom-hole zone of the formation - warming up of the near-well area; commissioning of the well with a specially selected technological mode of operation of deep-pumping equipment. The field results of testing the steam injection technology at well No. 3777 of Novo-Sheshminskaya Square are reflected, which showed the fundamental possibility of its application for the successful development of high-viscosity oil deposits. The study also found that for the wide application of the proposed technology, it is necessary to successfully solve a number of tasks, among which the most urgent is the issue of effective thermal insulation of hollow rods in order to minimize heat loss during injection of a special substance. Further development of the proposed technology of pumping production of high-viscosity oil lies in the use of modern materials for the production of underground equipment and improvement of the design of pumping units, aimed at increasing the parameter of the inter-repair period. The proposed technology can be used in the fields of the Volga-Ural oil and gas province, in particular, for example, at the Ashalchinsky field, which will significantly increase the percentage of recoverable reserves characterized as difficult to recover.
Increasing rice productivity in presence of climate change using Internet of Things (IoT)
Authors: Firmansyah Mas Ahsan Sandya , Suryani Erma
Published: March 2024

Climate change is becoming increasingly unpredictable. This also has an impact on agriculture, such as the increase in rice productivity. The internet of things is one of the latest technologies that can help increase land productivity. One of the uses of the Internet of things is to identify the temperature and rainfall. The problems currently faced by farmers are determining planting schedules and pest control that caused the decline in rice production. In this study, IoT will be designed to develop smart agriculture using system thinking to increase agricultural dryland productivity where agriculture in Madura is classified as dryland agriculture with rainfall amounts falling into the low-medium category of 50 -150 mm/day, this also affects the temperature in rice cultivation, so the use of IoT will focus on controlling the temperature, pest and stability of the rice paddy soaking water while planting rice until the harvest process for maximum results. The result of this study is a causal loop diagram of internet-based system thinking that can be used as a recommendation to increase agricultural land productivity with temperature, pest and irrigation control using IoT, especially in the form of sensor technology.
Palliative Systemtherapie des metastasierten Rektumkarzinoms
Authors: Seufferlein Thomas , Ettrich Thomas Jens
Published: March 2024

Die palliative Behandlung des metastasierten Rektumkarzinoms (mCRC) hat sich in den
letzten Jahren durch neue Behandlungsstrategien wie Induktions- und Erhaltungstherapien, die
Etablierung zielgerichteter Therapien und molekular definierte Therapien in bestimmten
Untergruppen wie MSI-H-Patienten erheblich erweitert. Der folgende Artikel stellt
evidenzbasiert therapeutische Optionen und Behandlungsalgorithmen vor.
Modalitäten des Stagings und der Diagnostik bei Rektumkarzinom
Authors: Al-Bourini Omar , Biggemann Lorenz , Seif Amir Hosseini Ali
Published: March 2024

Die Übersichtsarbeit „Modalitäten des Stagings und der Diagnostik bei Rektumkarzinom“ soll einen Einblick in die bildgebende Diagnostik bei Patient*innen mit Rektumkarzinom geben.

Das Rektumkarzinom ist eine der häufigsten Krebserkrankungen mit einer der höchsten Mortalitätsraten weltweit. Die rechtzeitige Diagnose und Therapie dieses Malignoms hat daher eindeutige sozioökonomische Implikationen.

Radiologische Bildgebung spielt bei der Therapieplanung eine entscheidende Rolle. Moderne Schnittbildverfahren werden zur Diagnosestellung und zur Ausbreitungsdiagnostik, dem Staging, eingesetzt.

Die Rolle der einzelnen bildgebenden Verfahren im Rahmen der Diagnostik beim Rektumkarzinom wird im Detail und deren Funktion im Allgemeinen erklärt. Ferner werden relevante Neuerungen und Forschungen auf dem Gebiet der Bildgebung präsentiert.

Speziell soll im Rahmen dieser Übersichtsarbeit der zunehmende Stellenwert der MRT-gestützten lokalen Ausbreitungsdiagnostik herausgestellt werden. Definierte diagnostische Kriterien auf Basis gängiger Empfehlungen werden erklärt. Es wird gezeigt, dass das lokale Staging mittels MRT bei Erstdiagnose und Verlaufskontrolle die therapierenden Disziplinen beim Festlegen eines Therapieplans unterstützen kann. Im Speziellen soll aufgezeigt werden, wie die MRT dabei die Festlegung eines chirurgischen Vorgehens maßgeblich beeinflussen kann.
Poland Syndrome: A Case Report
Authors: Parkash Satya , Pai Santosh
Published: March 2024

A case of Poland's syndrome characterised by anomalies in the shoulder girdle and symbrachydactyly is reported. First web was also involved. Method of correction adopted by us is described.
An Evaluation of VAS Reanastomosis Done by Microsurgery
Authors: Singh Arun Kumar , Tahiliani N. D.
Published: March 2024

A controlled experimental study of microsurgical vas reanastomosis has been done and compared with the conventional method. The superiority of microsurgical methods has been demonstrated, even though the procedure is more time consuming.
Cellular Immune Status In Patients With Cancer Of The Oral Cavity
Authors: Das S. N. , Khanna N. N. , Khanna Sushila
Published: March 2024

Cellular Immune Status was observed in 70 patients of squamous cell carcinoma of the oral cavity by in vitzo observation of absolute lymphocyte counts, T-cell counts and lymphocytes blastogenesis to PHA. The results were compared with 40 age matched normal controls. Absolute lymphooy te counts, absolute T-cell, T-rosette forming cells and blastogenic indax was significantly lower in oral cancer (P <.001) as compared to normal controls and further gradual decrease with increasing clinical stage, Well differentiated tumours were associated with higher T-cell counts and blastogenic index than the poorly differentiated tumours. The observations implies that the cellular immune showel a Tesponse is invariably impaired in oral cancer patients and is related to the malignant process in the host. The significant depression of absolute lymphocyte counts, T-cell counts and blastogenic index suggest that the existence of tumours mass itself may play an active role in subverting the host immune competence.
“Complete Vertical Cleft Of The Glans”
Authors: Sharma Rajendra N. , Singh Harinam , Chandra Tara
Published: March 2024

A rare case of complete vertical cleft of glans penis and a brief discussion, of the embryology is presented.
The Value Of Fluorescein In Predicting The Viability Of Flaps
Authors: Jacob O. J. , Nair K. Ramakrishnan , Nandakumar U. R. , Bharat P.
Published: March 2024

We recommend routine fluorescein examination whenever a major flap is manipulated. It will depict those areas of flaps which are dead at elevation, The examination is very safe, inexpensive and accurate.
Skin Graft Expander
Authors: Patel Dr. Kiran M.
Published: March 2024

Expanded grafts are very essential for resurfacing extensive open wounds. The grafts were used in cases of early wound cover and also in subsequent planned stages. The final effects were quite encouraging.
FILARIAL ELEPHANTIASIS OF LOWER EXTREMITY : A REVIEW
Authors: GOEL T. C.
Published: March 2024

Elephantiasis of the lower limb is one of the most troublesome and common manifestation of filariasis. It is a very old problem in India, as Manu described it as an obstacle to the invitation of a Priest to annual remembrance festivities ("Shradha karma"): and Sushruta, the father Indian Surgery, described it as "Shleepada". Price (1984) has described the history of elephantiasis in great detail.
UNDERSTANDING DUFOURMENTEL FLAP DESIGN
Authors: CHANDRA RAMESH , SINGH ARUN KUMAR
Published: March 2024

Dufourmentel flap is a local transposition flap for rhombic defects. The details of its geometrical design have been discussed. Paper models and experimental study on canine skin have also been undertaken to study the biomechanics of this flap for better understanding.
CORRECTION OF DEFORMITIES FOLLOWING DEEP BURNS ON EXTENSOR SURFACE OF THE HAND
Authors: SAWHNEY C. P.
Published: March 2024

Postburn contractures on the extensor aspect of hand produce crippling deformities. The deformities produced vary from extension contractures with or without associated web contractures, scar syndactyly, non-healing ulcers, disrupted extensor mechanism, contractures of musculotendinous units and capsular ligaments. Stiffness and/or subluxations of joints further complicates the problems. Release of contracture, skin grafting, judicious splintage and physiotherapy has been the sheet-anchor of treatment. With this regime it has been possible to restore near normal function in majority of the cases at our centre.
USE OF FASCIOCUTANEOUS FLAPS FOR DEFECTS OF LOWER EXTREMITY
Authors: SINGH V. S. , SINHA J. K. , BHATTACHARYA V. , TRIPATHl F. M.
Published: March 2024

The fasciocutaneous flaps were raised in 12 patients who had obstinate skin defects in the leg. The undelayed transposition, cross leg and bipedicle advancement fascioculaneous flaps were planned and executed. These are simpler and safer flaps in comparison to myocutaneous and free flaps. A safe length-base ratio is 3:1. The blood vessels in the deep fascia enter through the intermuscular septum. The fascial septal perforators carry the main blood supply to the deep fascia and the overlying skin. Patients with crush injury of the leg with complicated fracture and bruising in the donor area were associated with oedema and haematomas in various surgical planes of the leg. One should be cautious in designing fasciocutaneous flap in such cases.
RECANALISATION OF VAS DEFERENS UNDER MAGNIFICATION
Authors: SAHA ILA , POLLE N. , GANGULI S. , GANGULI A. C.
Published: March 2024

A total of forty vasectomised cases were treated by recanalisation of vas deferens under ophthalmic loupe magnification. Semen analysis has been the criterion for evaluation of success or failure of recanalisation in our series. Clinical success was noticed in 86% of our cases. The interval between vaseclomy and recanalisation does not substantially affect the results.

If azospermia persists for about 3 months after recanalisation, the operation was considered a failure. The sperm count, motility and morphology gradually improves with the passage of time after recanalisation. Conception usually takes place after an interval of l 1/2 years after recanalisation of vas deferens.
CRANIOFACIAL “COUP DE SABRE” INJURY—A CASE REPORT
Authors: SAHA S. S. , KHAZANCHI R. K. , DHAWAN I. K.
Published: March 2024

A case of extensive craniofacial injury sustained in a road traffic accident is described, in which the face was nearly bivalved. Immediate resuscitation and reconstruction was done with a good result.
RECENT TRENDS IN BREAST RECONSTRUCTION
Authors: Mohan D , Venkataramakrishnan V
Published: March 2024

An overview of the current concepts in breast reconstruction with the practical considerations for each reconstructive option is presented. The various methods in vogue should be tailored to the patients' needs and expectations. The newer techniques like free TRAM(Transverse Rectus Abdominis Myocutaneous flap) breast reconstruction are becoming more popular due to their superior aesthetic result.
HEALING OF DIABETIC AND THERMAL WOUNDS BY HERBAL CREAM, IH-WH4 AND HERBERIN
Authors: Chatterjee S , Rao A T , Das S N
Published: March 2024

The wound healing efficacy of IH-WH4 and HERBERIN was evaluated in diabetic and burn wound subjects. Histopathological studies revealed that administration of these two products hastened the formation of granulation tissue alongwith angiogenesis and fibroplasia.
OUR EXPERIENCES WITH PLATYSMA MYOCUTANEOUS FLAP IN HEAD AND NECK RECONSTRUCTION
Authors: Cherian T , Kurien J , Vijaykumar D K , Chittoria R
Published: March 2024

In eighty-five patients under this study ipsilateral platysma myocutaneous flaps were used. The various regions reconstructed were tongue (47%), buccal mucosa (27%), floor of mouth (14%), lower alveolus (4%), maxilla (4%), lower lip (2%) and face (2%). Partial flap necrosis was noticed in 17 cases (20%), complete flap necrosis in six cases (7%) and wound infection in three cases ( 3%). The platysma myocutaneous flap provides a less bulky and versatile flap for head and neck reconstruction.
Depressed Fracture of Calvarial Bone following Rapid Scalp Expansion for Post-burn Alopecia in a Child
Authors: Kumar P , Bhaskara K G , Thomas P C
Published: March 2024

Depressed calvarial fracture as a complication of scalp expansion in a 3 1/2-year-old girl who underwent 8cm scalp expansion over 48 days is being reported. A technique for placement of tissue expander through multiple small radically placed incisions is described to prevent implant exposure.
The Use of Distraction Osteogenesis for treatment of the mandibular deformity in hemi facial microsomia: A case report of the double osteotomy technique
Authors: Krishna R , Kumar S , Singh A K , Bhatnagar S K , Kumar V
Published: March 2024

A patient presenting with hemi facial microsomia with Grade IIB mandibular deformity was treated by distraction osteogenesis after double osteotomy of the ramus and the body. A satisfactory facial symmetry was achieved following the surgery without any complications.
The Impact of Bariatric Surgery on Postoperative Complications and Outcomes following Primary Total Hip Arthroplasty
Authors: Liu Ivan Z. , Kubsad Sanjay , Gu Alex , Wang Kevin Y. , Malyavko Alisa , Mikula Jacob D. , Campbell Joshua C. , Thakkar Savyasachi C.
Published: March 2024

The prevalence of obesity is significantly increasing in the U.S. population and is associated with both increased incidence of total hip arthroplasty (THA) and potentially worsened postoperative outcomes. Current guidelines strongly encourage exercise-based weight loss in morbidly obese THA candidates to decrease patient risk profiles, but data on the impact of receiving bariatric surgery (BS) for weight loss prior to THA are limited and controversial. The purpose of this study was to clarify the impact of BS on postoperative complications and outcomes following THA. Using Current Procedural Terminology, International Classification of Diseases (ICD)-9, and ICD-10 codes, patients undergoing primary THA from 2010 to 2018 were retrospectively collected from PearlDiver's Mariner dataset. Patients were divided into three cohorts who underwent primary THA: nonmorbidly obese patients, morbidly obese patients, and morbidly obese patients who underwent THA within 2 years of BS. Patients were subsequently matched based on age, Charlson Comorbidity Index, gender, and tobacco use. The primary outcome of this study was the frequency of 90-day and 2-year postoperative complications following primary THA. Compared with morbidly obese non-BS patients, morbidly obese patients who underwent BS prior to receiving a primary THA were less likely to have blood transfusion (4.24 vs. 7.44%, p < 0.05), cellulitis (2.92 vs. 6.11%, p < 0.05), myocardial infarction (2.39 vs. 4.91%, p < 0.05), and deep venous thrombosis (1.06 vs. 3.05%, p < 0.05) at 90-day follow-up. The remaining 90-day postoperative outcomes were not found to be statistically different between cohorts. There were no significant differences in 2-year surgical complications between the morbidly obese non-BS cohort and morbidly obese BS cohort. In this study, we found that morbidly obese patients who underwent BS prior to THA had fewer 90-day medical complications and no significant differences in 2-year surgical complications compared with those who did not undergo BS prior to THA.
Political fatalism and the (im)possibility of social transformation
Authors: Slothuus Lukas
Published: March 2024

How can the world be improved if the people inhabiting it do not believe they can transform it? A belief in such political fatalism is an important obstacle to social transformation, yet underexplored in the contemporary political theory literature. Political fatalism can be understood as a commitment to the belief that human agency cannot effectuate social transformation. In this article, I provide a typology of such political fatalism, considering its two main forms: fatalism of inevitability as the positive version that humans do not have the power to affect positive social change, and fatalism of impossibility as the negative version that human agency does not play a role in avoiding negative social change such as climate catastrophe. Focussing particularly on the more pressing contemporary problem of the fatalism of impossibility, I develop three distinct dimensions along which fatalism has an impact: the cognitive, the affective, and the practical. Finally, I offer solutions, focussing on how to combine interventions on the cognitive, affective, and practical levels: historically sensitive critique, imagination, and a combination of bounded spontaneism and long-term political organisation.
Consequences of firm-specific stock price crashes on analyst forecasts: Evidence from China
Authors: Fan Yunqi , Zhang Yanwei
Published: March 2024

The phenomenon of stock price crash events (SPCs) has always attracted market attention, but existing research mainly focuses on its causes or determinants and rarely examines the consequences of SPCs. This study aims to fill this gap by examining the consequences of firm-specific stock price crash events (SPCs) on analyst forecast accuracy. Using the sample of analysts and listed companies from 2001 to 2020 and employing a difference-in-differences design, we find that after the company’s stock price crashed, the analyst forecast error decreased and the accuracy increased. For analysts who have not conducted site visits before SPC, and have no geographical advantages, this effect is more obvious, thus validating our hypothesis following analyst attention theory. Additional analysis shows that SPCs stimulate forecast accuracy more significantly for lowly-reputed analysts than for highly-reputed analysts. Channel analysis documents that, for the aforementioned group of analysts, the enhancement effect of SPCs on analyst forecasts is mediated by analyst effort increasing. This study adds to the evidence that SPCs bring positive externalities from the analyst perspective, that is, SPCs attract the attention of some analysts and improve their forecast accuracy. This study also enhances our understanding of analyst behavior under uncertainty, finally enriching the literature on the determinants of analyst forecast accuracy.
How does the environmental attention of local governments affect regional green development? Empirical evidence from local governments in China
Authors: Tu Chaoyang , Liang Yuxi , Fu Yong
Published: March 2024

Due to the continuous progress of constructing sustainable environments in China, the role played by the Chinese central government as the main body for promoting green development is worth studying. Because China’s ecological civilization building has been steadily progressing. Governments at all levels in China have prioritised the development of environmental civilization as a key aspect of regional growth. However, the actual impact and mechanisms of influence of this construction still require further investigation. This paper constructs a government environmental attention index using word frequency found in the Report on the Work of the Government. It uses a long difference model to study the impact and mechanism of government environmental attention on urban green efficiency, carbon emissions and air quality. The results show that the government’s ecological attention can improve green efficiency, and air quality, but it can also lead to increased carbon emissions, and the impact is particularly evident in the eastern and western regions of the country. This is because the government’s emphasis on the environment significantly impacts on environmental regulations and technological progress, and is directly influenced by fiscal bias and financial pressure. Given the results, we put forward some policy suggestions that local governments should improve the intensity of local environmental regulation, encourage green technology innovation, provide encouraging conditions for environmental development, and establish a long-term strategic vision. The findings in this study has implications for promoting the implementation of local governments’ environmental protection and the development of sustainable societies in China.
Research on surrogate models and optimization of equipment dynamics for complex systems
Authors: Yang Haigen , Bai Xu , Wang Chao
Published: March 2024

In this paper, we use tracked vehicles as an example to study complex systems and surrogate model building method. Due to the high cost and long development cycle associated with the traditional development approach, involving static design and experimental verification, there is an urgent need to explore an effective dynamic optimization design method to enhance vibration reduction performance. This paper introduces a methodology for constructing a model of complex equipment surrogate, aimed at streamlining subsequent parameter optimization processes. The dynamics model of the tracked vehicle is utilized, and the root-mean-square value of plumb vertical acceleration at the center of mass is selected as the dynamic performance index. The impact of structure parameters on dynamic performance is analyzed, and a range of design parameters are determined. The optimal Latin hypercube experimental design method is employed to generate sample data. A radial basis function neural network, optimized by particle swarm optimization, is used to construct a dynamic surrogate model for the tracked vehicle. The surrogate model constructed in this paper greatly reduces the time cost in optimizing complex equipment parameters. In the past, parameter optimization required conducting numerous simulations to collect data, with each simulation taking about 700 s. However, the surrogate model introduced in this paper only requires ∼100 s for completion. This significant reduction in time not only saves costs but also maintains a high level of accuracy.
Magnon dispersion, magnetization, and thermodynamic properties of 2D-Sc/GaAs diluted magnetic semiconductor (DMS)
Authors: Geffe Chernet Amente
Published: March 2024

In this paper, the effect of magnon scattering, light–matter coupling strength, temperature, and applied dc field H0 on magnon dispersion, density of magnons, magnetization, and thermodynamic properties of 2D-Sc/GaAs DMS material is studied. The Green function formalism is used to find the magnon dispersion and density in single-mode excitation employing the quantum field theory. Our findings indicate that ferromagnetic phase change is obtained within a limited low-temperature range based on the product Ω0T5/2, which remains below unity and varies with the amount of magnon scattering factor Ω0. It was presumed that the density of localized magnetic impurities can be controlled by taking into account the numerical stability with the number of holes required for mediation, and therefore, a scandium (Sc) dopant and its kind, which have a double functionality of creating holes and adding magnetic impurities from their 3d suborbital, are the best choice to replace those with higher spin magnetic moments. We also observe that the magnetic curves broaden as the temperature further rises and decrease with the enhancement of the magnon scattering factor, perhaps, due to quenching of fermionic spins ceasing the interband excitation. However, in the absence of this factor, the magnetization decreases linearly with the increase in the temperature, breaking the Bloch T3/2 low, perhaps, introducing anomalous condition to such 2D materials. The light–matter coupling strength and the dc field H0 are alleged to be responsible for the formation of the energy gap and variation of magnon dispersion. This work suggests that there is a point above which the temperature TC may not rise with the increase in the impurity concentration x due to magnon scattering, distressing the entire thermodynamic property.
Hall measurements on nitrogen-doped Ib-type synthetic single crystal diamonds at temperatures 550–1143 K
Authors: Buga S. G. , Kvashnin G. M. , Kuznetsov M. S. , Kornilov N. V. , Luparev N. V. , Prikhodko D. D. , Terentiev S. A. , Blank V. D.
Published: March 2024

Synthetic nitrogen-doped diamond single crystals have various high-tech applications, but their electronic properties have not been sufficiently studied. In this research, we investigated temperature dependencies in the range T = (550–1143) K of the electrical resistivity and Hall mobility in synthetic single-crystal Ib-type diamonds doped with nitrogen during growth. A series of experimental samples were cut from diamond crystals grown by temperature gradient high-pressure high-temperature (TG-HPHT) and chemical vapor deposition (CVD) methods. They contain (0.085–6.5) × 1019 cm−3 single substitutional nitrogen atoms (C-centers) as measured by optical spectrometry methods. The Hall mobility of free electrons decreases from 600 to 150 cm2 V−1 s−1 in the CVD grown sample with the lowest N content and from 300 to 100 cm2 V−1 s−1 in highly doped HPHT grown samples in the temperature range of 550–900 K. At T = (900–1100) K, the mobility decreases to 50 cm2 V−1 s−1 in highly doped samples. The activation energies of electrical conductivity Ea and impurity-to-band energies of nitrogen donors ED decrease with increasing N concentration in the ranges (1.55–1.32) and (1.63–1.33) eV, respectively. The lowest compensation ratio k ∼ 1% in the moderately doped CVD diamond is unique for n-type diamonds. Typical values of k in highly N-doped crystals are in the range of 10%–20%, facilitating the use of N-doped diamonds in durable high-temperature electronic devices.
The influence of steady-state thermal blooming effect on the quality of underwater laser power transmission
Authors: Zhu Xuegui , Yu Wenchao , Liu Gengjian , Zhang Chenxing
Published: March 2024

Aiming at the energy supply problem of underwater equipment such as manned deep submarines, submarine base stations, etc., this paper proposes an underwater high-energy laser wireless power transmission system and focuses on analyzing the influence of the steady-state thermal blooming effect on the quality of underwater high-energy laser power transmission. First, the intensity distributions under the influence of the thermal blooming effect are numerically simulated based on the multiple phase-screen method and the fast Fourier transform, considering the changes in the initial beam radius, transmission distance, transmitting power, wavelength, absorption coefficient of the water medium, and isobaric specific heat capacity. Emphatically, transmission efficiency and beam flux contrast are used to characterize the quality of power transmission and then find the suitable laser modes and seawater environment for underwater power transmission. The results indicate that reducing the thermal blooming effect may increase the efficiency of light energy transmission, but it will also decrease the photoelectric conversion efficiency of photovoltaic cells. Therefore, for balancing the energy transfer efficiency and the beam flux contrast, it is necessary to choose appropriate initial laser parameters based on actual underwater environmental parameters. Our study is helpful for the design of the underwater laser wireless power transmission system.
The industrial robot reducer testing instrument dynamic torsional moment measurement error calibration, based on the Bisquare curve fitting–improved Bayes particle swarm optimization–nonlinear echo state network (BCF–IBPSO–NESN) method
Authors: Yu Zhen , Zhang Yuan , Liu Xiaomin , An Qi , Suo Shuangfu
Published: March 2024

Industrial robots are important components in the production and manufacturing industry. As a core component of the industrial robot, the industrial robot reducer plays a crucial role in the performance of the entire industrial robot. The error analysis and accuracy traceability of the industrial robot reducer testing instrument are of great significance in improving the quality of the precision reducer. Therefore, it is essential to calibrate the dynamic torsional moment measurement error of the instrument. The features of the dynamic torsional moment measurement error are analyzed in this paper. Based on these features, a new dynamic torsional moment measurement error calibration method is proposed based on the Bisquare curve fitting–improved Bayes particle swarm optimization–nonlinear echo state network (BCF–IBPSO–NESN) algorithm. The proposed method focuses on calibrating the dynamic torsional moment measurement error of the industrial robot reducers in real time. The experimental results show that the dynamic torsional moment measurement error of the input side torsional moment measurement module and the output side torsional moment measurement module can be reduced to ±0.05 Nm and ±1 Nm, respectively. The contribution of this paper is that the method calibrates the dynamic torsional moment measurement error. It supplies a guideline for calibrating the dynamic torsional moment measurement error of the instrument under any load.
Thermal noise calibration of functionalized cantilevers for force microscopy: Effects of the colloidal probe position
Authors: Archambault Aubin , Crauste-Thibierge Caroline , Bellon Ludovic
Published: March 2024

Colloidal probes are often used in force microscopy when the geometry of the tip–sample interaction should be well controlled. Their calibration requires an understanding of their mechanical response, which is very sensitive to the details of the force sensor consisting of a cantilever and the attached colloid. We present some analytical models to describe the dynamics of the cantilever and its load positioned anywhere along its length. The thermal noise calibration of such probes is then studied from a practical point of view, leading to correction coefficients that can be applied in standard force microscope calibration routines. Experimental measurements of resonance frequencies and thermal noise profiles of raw and loaded cantilevers demonstrate the validity of the approach.
Discrete fiber skeleton strengthened magnetorheological grease and a novel H–B model based on fiber parameters
Authors: Wang Yingjian , Wang Meng , Gao Peixin , Yu Tao , Xi Jun
Published: March 2024

Magnetorheological fluid (MRF) porous fabric composite has been demonstrated to improve the shear properties of MRF. Non-woven fabric is manufactured from a multitude of fibers through spinning or melt-blown processing methods. As the fundamental unit of non-woven fabric, fibers without spinning or melt-blown directly influence the shear properties of magnetorheological (MR) materials. However, the effect of unprocessed fiber on the shear properties of MR grease remains uncertain. This study introduces a novel MR grease with fiber threads (MRG-FT) by incorporating fiber threads into MRG. The effects of fiber thread length, mass fraction, and material type on MRG shear stress are investigated. Compared to conventional MRG, the maximum shear stress of MRG-FT is increased by 31.8% under the magnetic field of 0.64 T. A novel Herschel–Bulkley–Fiber (H-B-F) model that considers fiber parameters (tenacity, mass fraction, etc.) is proposed based on the H–B model. To validate the enhancement of MRG by fiber threads, a linear damper based on shear mode has been designed and tested. The results demonstrate a 23.8% increase in the maximum damping force of MRG-FT compared to conventional MRG under an excitation current of 1.6 A. This study reveals the influence of fiber threads, which directly influences the shear properties of MRG upon the application of the magnetic field. The maximum damping force of the MRG can be increased by 23.8% by only 1.5% mass fraction of fibers.
Experimental upper bounds for resonance-enhanced entangled two-photon absorption cross section of indocyanine green
Authors: He Manni , Hickam Bryce P. , Harper Nathan , Cushing Scott K.
Published: March 2024

Resonant intermediate states have been proposed to increase the efficiency of entangled two-photon absorption (ETPA). Although resonance-enhanced ETPA (r-ETPA) has been demonstrated in atomic systems using bright squeezed vacuum, it has not been studied in organic molecules. We investigate for the first time r-ETPA in an organic molecular dye, indocyanine green (ICG), when excited by broadband entangled photons in near-IR. Similar to many reported virtual state mediated ETPA (v-ETPA) measurements, no r-ETPA signals are measured, with an experimental upper bound for the cross section placed at 6(±2) × 10−23 cm2. In addition, the classical resonance-enhanced two-photon absorption (r-TPA) cross section of ICG at 800 nm is measured for the first time to be 20(±13) GM, where 1 GM equals 10−50 cm4 s, suggesting that having a resonant intermediate state does not significantly enhance two-photon processes in ICG. The spectrotemporally resolved emission signatures of ICG excited by entangled photons are also presented to support this conclusion.
Electron impact partial ionization cross sections: R-carvone, 2-butanol, imidazole, and 2-nitroimidazole
Authors: Shanmugasundaram Suriyaprasanth , Agrawal Rounak , Gupta Dhanoj
Published: March 2024

We calculate electron impact partial and total ionization cross sections of R-carvone (C10H14O), 2-butanol (C4H10O), imidazole (C3H4N2), and 2-nitroimidazole (C3H3N3O2). We have used the Binary Encounter Bethe (BEB) model to obtain total electron impact ionization cross sections (TICSs). The modified BEB method in combination with mass spectrum data of the molecules is used to calculate the partial ionization cross section (PICS) of the cationic fragments dissociating from the parent molecule. Our PICS data for R-carvone and 2-butanol are in good agreement with the experimental data for all the cation fragments along with the TICS data. For imidazole and 2-nitroimidazole, the estimates of the PICS are reported for the first time in the present study. We have found that both the modified BEB method and the mass spectrum dependence method work effectively to estimate PICS if we have information about the appearance energies and relative abundance data of the target under investigation.
MXene/carbonized bagasse fiber aerogel thermal insulation material
Authors: Zhu MengQi , Lin HaiTao , Shan Xiaoxiao , Jiang Yong
Published: March 2024

Since the existence of high-density gas voids, Ti3C2Tx (MXene), especially aerogels, whose diverse surface chemistry and porous hollow structure break the continuity of the heat transmission path and effectively reduce its thermal conductivity, has broad prospects in the field of new thermal insulation materials. Herein, MXene and carbonized bagasse fiber (CBF) are compounded into a special aerogel through hydroxyethyl cellulose, which not only reduces its cost but also improves its thermal insulation and mechanical properties. MXene/CBF aerogels have low thermal conductivity (69 mW·m−1·K−1) and excellent compressive stress (1.04 MPa), which make them to be used in the field of environmental protection and heat insulation materials.
Enhanced magnetic and electrical properties of Co-doped Fe5GeTe2
Authors: Zhang Junchao , Wang Ziwen , Xing Yu , Luo Xiong , Wang Zhicheng , Wang Guopeng , Shen Aoli , Ye Haoran , Dong Shuai , Li Linglong
Published: March 2024

The layered van der Waals material Fe5GeTe2 (F5GT) has emerged as a captivating candidate for room-temperature spintronics, boasting inherent ferromagnetic behavior. Nevertheless, the intricate magnetic characteristics of F5GT beckon a deeper exploration. Here, we present the synthesis of (Fe1−xCox)5GeTe2 (x = 0–0.47) single crystals and a comprehensive investigation of cobalt (Co) doping effects on the magnetic and transport properties. The Curie temperature (TC) enhancement of F5GT is revealed in magnetic measurements, surpassing room temperature and reaching 325 K at x = 0.24. Furthermore, Co doping induces an adjustment of the easy magnetization direction of F5GT toward the in-plane orientation, affording a significant amplification of magnetic anisotropy. Notably, for x = 0.47, an antiferromagnetic ground state emerges with a transition temperature (TN) of 340 K, accompanied by field-induced spin-flop transitions. In addition, our electrical transport measurements yield complementary insights into the influence of Co doping on F5GT, unraveling the understanding of the strong spin-charge coupling within the materials. First-principles calculations demonstrate that Co doping plays an important role in the influence of interlayer stacking and magnetic ground state. This investigation unlocks the enormous potential of Co-doped F5GT for high-performance room-temperature spintronics applications.
Analysis of active screen low temperature plasma-assisted deposition of iron nitride thin films on silicon (100) substrate
Authors: Asghar Muhammad , Bashir Muhammad Imran , Tayyab Muhammad , Shafiq Muhammad , Naz Muhammad Yasin , Ibrahim Ahmed Ahmed , Shoaib Muhammad
Published: March 2024

Thin film technology has gained significant attention in the industry due to its superior properties in comparison to bulk materials. Specifically, iron nitride-based thin films are a fascinating area of research in semiconductor technologies. The crystal structure and optical properties of these films are highly dependent on the growth method, deposition technique, gas flow, pressure, and several other factors. In this work, we prepared polycrystalline thin films of iron nitride on silicon (100) substrates by using the active screen low temperature plasma-assisted method. These films are deposited under the varying atmosphere of nitrogen and hydrogen in four proportions: 80% N2 + 15% H2; 60% N2 + 35% H2; 40% N2 + 55% H2; and 20% N2 + 75% H2, along with 5% argon to investigate its influence on the structural, morphological, and optical properties. The structural properties are determined by x-ray diffraction and revealed a mixture of ζ-Fe2N, ε-Fe3N, and γ′-Fe4N phases. Surface morphology is analyzed by scanning electron microscopy, which confirms the formation of a thin layer on the substrate. In addition, UV–Vis spectrophotometry is used to assess the optical response and bandgap energy of the samples. The result of UV–Vis optical diffuse reflectance spectra shows a decrease in the bandgap from 3.17 to 3.06 eV of substrate. For the S4 sample, we obtained a pure Fe4N phase, showing a significant decrease in the energy bandgap.
First-principles study of high-pressure structural phase transition and superconductivity of YBeH8
Authors: Du Jianhui , Jiang Qiwen , Zhang Zihan , Zhao Wendi , Chen Ling , Huo ZiHao , Song Hao , Tian Fubo , Duan Defang , Cui Tian
Published: March 2024

The theory-led prediction of LaBeH8, which has a high superconducting critical temperature (Tc) above liquid nitrogen under a pressure level below 1 Mbar, has been experimentally confirmed. YBeH8, which has a structural configuration similar to that of LaBeH8, has also been predicted to be a high-temperature superconductor at high pressure. In this study, we focus on the structural phase transition and superconductivity of YBeH8 under pressure by using first-principles calculations. Except for the known face-centered cubic phase of Fm3̄m, we found a monoclinic phase with P1̄ symmetry. Moreover, the P1̄ phase transforms to the Fm3̄m phase at ∼200 GPa with zero-point energy corrections. Interestingly, the P1̄ phase undergoes a complex electronic phase transition from semiconductor to metal and then to superconducting states with a low Tc of 40 K at 200 GPa. The Fm3̄m phase exhibits a high Tc of 201 K at 200 GPa, and its Tc does not change significantly with pressure. When we combine the method using two coupling constants, λopt and λac, with first-principles calculations, λopt is mainly supplied by the Be–H alloy backbone, which accounts for about 85% of total λ and makes the greatest contribution to the high Tc. These insights not only contribute to a deeper understanding of the superconducting behavior of this ternary hydride but may also guide the experimental synthesis of hydrogen-rich compounds.
Theoretical study on isostructural pressure-induced phase transition of solid ethane at extremely low temperature
Authors: Zhu Sheng-Hai , Cheng Xin-Lu , Liu Qi-Jun , Liu Zheng-Tang
Published: March 2024

The stable crystalline phase of ethane at atmospheric pressure can only exist at extremely low temperatures, but the pressure-induced phase transition of ethane at these low temperatures has received little attention from researchers. Based on the calculations of Raman vibrational modes and 2D fingerprints of P21/n-C2H6 under different pressures, we found that ethane at 0 K exhibits an isostructural phase transition under 3 GPa. The extremely low temperature (0 K) suppresses the appearance of room temperature crystalline plastic phase A but promotes the higher-pressure phase B at the lower pressure point.
A novel dual-core current transformer based on TMR sensor and its measuring characteristics
Authors: Zhang Zhexuan , Tian Cuihua , Guo Junhua , Wang Yu , Liu Zhaojie , Zhao Yingying , Lu Jian , Ye Weihua
Published: March 2024

Current transformers (CTs) are the most widely used measurement instrumentation in power grids. Nevertheless, CT saturation gives rise to large measurement errors, which may have bad repercussions for the power system. In order to deal with the problem of CT saturation, a novel dual-core current transformer based on tunnel magnetoresistance sensor (DTCT) is proposed. Theoretical analyses, finite element method (FEM) simulations and accuracy tests are carried out to validate the practicability and effectiveness of the proposed DTCT. The simulation and experimental results manifest that the steady-state and transient characteristics of the DTCT are outstanding.