bluuebunny/crossref_metadata_2025 huggingface dataset:
Work-Related Sleep Disorders: Causes and Impacts
Authors: Gusman Elen , Standlee Jordan , Reid Kathryn J. , Wolfe Lisa F.
Published: April 2023

Insufficient sleep syndrome, shift work disorder, and obstructive sleep apnea (OSA) not only significantly impact the health of affected individuals, but also pose a threat to public safety. This article describes the clinical manifestations and impact of these sleep disorders, particularly as they pertain to workers' health and those with safety-sensitive positions. Sleep deprivation, circadian rhythm disruptions, and excessive daytime sleepiness—hallmarks of insufficient sleep, shift work disorder, and OSA, respectively—all lead to a series of cognitive deficits and impaired concentration that affect workers in a wide variety of fields. We describe the health consequences of these disorders along with treatment strategies, with a focus on current regulatory standards and the under-recognition of OSA in commercial drivers. Given its large scale, there is a need for improved guidelines and regulations for the screening, diagnosis, treatment, and long-term follow-up of OSA in commercial motor vehicle drivers. Increased recognition of the ways in which these sleep disorders impact workers will pave the way for significant improvements in occupational health and safety.
The Impact of Respiratory Therapist Performed Point-of-Care Lung Ultrasound on the Respiratory Care in Neonates, Manitoba Experience, Canada
Authors: Elsayed Yasser , Sheldon Josh , Gigolyk Shere
Published: April 2023

Objective We aimed to evaluate the impact of the registered respiratory therapist (RRT) performed point-of-care lung ultrasound (POC-LUS) on patient management in the neonatal intensive care unit (NICU).

Study Design This is a retrospective cohort study of neonates who had RRT performed POC-LUS in two level III NICUs in Winnipeg, Manitoba, Canada. The analysis aims mainly to describe the implementation process of the POC-LUS program. The primary outcome was the prediction of the change in clinical management.

Results A total of 136 neonates underwent 171 POC-LUS studies during the study period. POC-LUS resulted in a change in clinical management following 113 POC-LUS studies (66%), while it supported continuing the same management in 58 studies (34%). The lung ultrasound severity score (LUSsc) was significantly higher in the group with worsening hypoxemic respiratory failure and on respiratory support than infants on respiratory support and stable or not on respiratory support, p < 0.0001. LUSsc was significantly higher in infants on either noninvasive or invasive than those not on respiratory support, p-value <0.0001.

Conclusion RRT performed POC-LUS service utilization in Manitoba improved and guided the clinical management of a significant proportion of patients who received the service.
Accuracy of Wireless Pulse Oximeter on Preterm or <2.5 kg Infants
Authors: Thomas Micaela , Day Heather , Petersen Brandy , Marchant Trisha , Jones Cory , Singh Yogen , Chan Belinda
Published: April 2023

Objective Monitoring heart rate (HR) and oxygen saturation (SpO2) in infants is essential in the neonatal intensive care unit. Wireless pulse oximeter technology has been advancing but with limited accuracy data on preterm infants. This observational study compared HR and SpO2 of the wireless Owlet Smart Sock 3 (OSS3) to the wired Masimo SET (Masimo) pulse oximeter in preterm or <2.5 kg infants.

Study Design Twenty-eight eligible infants were enrolled. They weighed between 1.7 and 2.5 kg and were without anomalies or medical instability. OSS3 and Masimo simultaneously monitored HR and SpO2 for 60 minutes. The data were aligned by time epoch and filtered for poor tracings. The agreement was compared using the Pearson's correlation coefficient, the Bland–Altman method, average root mean square (ARMS), and prevalence and bias adjusted kappa (PABAK) analyses.

Results Two infants' data were excluded due to motion artifacts or device failures. The corrected gestational age and current weights were 35 ± 3 weeks and 2.0 ± 0.2 kg (mean ± standard deviation), respectively. Over 21 hours of data showed that HR was strongly correlated between the two devices (r = 0.98, p < 0.001), with a difference of −1.3 beats per minute (bpm) and the limit of agreement (LOA) −6.3 to 3.4 bpm based on the Bland–Altman method. SpO2 was positively correlated between the two devices (r = 0.71, p < 0.001) with a SpO2 bias of 0.3% (LOA: −4.6 to 4.5%). The estimated ARMS of OSS3 compared with Masimo was 2.3% for SpO2 in the 70 to 100% range. The precision decreased with lower SpO2. A strong agreement (PABAK = 0.94) was between the two devices on whether SpO2 was above or below 90%.

Conclusion OSS3 provided comparable HR and SpO2 accuracy to Masimo in preterm or <2.5 kg infants. Motion artifacts, lack of arterial blood gas comparisons, and lack of racial and ethnic diversity are the study limitations. More OSS3 data on the Lower HR and SpO2 ranges were needed before implementing inpatient use.

Key Points
Risk Factors for Postpartum Depression and Severe Distress among Mothers of Very Preterm Infants at NICU Discharge
Authors: Hofheimer Julie A. , McGowan Elisabeth C. , Smith Lynne M. , Meltzer-Brody Samantha , Carter Brian S. , Dansereau Lynne M. , Pastyrnak Steven , Helderman Jennifer B. , Neal Charles R. , DellaGrotta Sheri A. , O'Shea Thomas Michael D. , Lester Barry M.
Published: April 2023

Objective To identify psychological, medical, and socioenvironmental risk factors for maternal postpartum depression (PPD) and severe psychological distress (SPD) at intensive care nursery discharge among mothers of very preterm infants.

Study Design We studied 562 self-identified mothers of 641 infants born <30 weeks who were enrolled in the Neonatal Neurobehavior and Outcomes in Very Preterm Infants Study (NOVI) conducted in nine university-affiliated intensive care nurseries. Enrollment interviews collected socioenvironmental data, depression, and anxiety diagnoses prior to and during the study pregnancy. Standardized medical record reviews ascertained prenatal substance use, maternal and neonatal medical complications. The Edinburgh Postnatal Depression Scale and Brief Symptom Inventory were administered at nursery discharge to screen for PPD and SPD symptoms, respectively.

Results Unadjusted analyses indicated mothers with positive screens for depression (n = 76, 13.5%) or severe distress (n = 102, 18.1%) had more prevalent prepregnancy/prenatal depression/anxiety, and their infants were born at younger gestational ages, with more prevalent bronchopulmonary dysplasia, and discharge after 40 weeks postmenstrual age. In multivariable analyses, prior depression or anxiety was associated with positive screens for PPD (risk ratio [RR]: 1.6, 95% confidence interval [CI]: 1.1–2.2) and severe distress (RR: 1.6, 95% CI: 1.1–2.2). Mothers of male infants had more prevalent depression risk (RR: 1.7, 95% CI: 1.1–2.4), and prenatal marijuana use was associated with severe distress risk (RR: 1.9, 95% CI: 1.1–2.9). Socioenvironmental and obstetric adversities were not significant after accounting for prior depression/anxiety, marijuana use, and infant medical complications.

Conclusion Among mothers of very preterm newborns, these multicenter findings extend others' previous work by identifying additional indicators of risk for PPD and SPD associated with a history of depression, anxiety, prenatal marijuana use, and severe neonatal illness. Findings could inform designs for continuous screening and targeted interventions for PPD and distress risk indicators from the preconception period onward.

Key Points
Effect of Statins on the Inflammatory Markers in Patients with Coronary Artery Disease
Authors: Premnath Sujatha Mahadevarao , Nanda Sunil Kumar , Ray Lopamudra , Arokiaraj Mark Chirstopher
Published: April 2023

Introduction Atherosclerosis mediated by inflammatory markers is the corner stone in the pathology of coronary artery disease (CAD). Hyperlipidemia, one of the risk factors is treated with statins. Statins also have a pleotropic role in reducing inflammation. Effect of statins on two inflammatory markers pentraxin 3(PTX 3) and high sensitivity C-reactive protein (hs-CRP) is explored in this study.

Objective This article estimates the levels of serum PTX 3 and hs-CRP in CAD patients with and without statin therapy and correlates the levels with low-density lipoprotein cholesterol (LDL-c) and high-density lipoprotein cholesterol (HDL-c) in CAD patients without statin therapy.

Material and Methods This was a cross-sectional study conducted on 62 patients with CAD diagnosed by coronary angiogram. They were divided into two groups. Group I were the CAD patients on statin therapy and group II were CAD patients who never had any lipid lowering drugs irrespective of their lipid values. Serum PTX3, hs-CRP, and lipid profile were estimated in these groups. Comparison between the groups was done using Student's t-test and correlation analyzed using Pearson's correlation.

Results Serum PTX 3 and hs-CRP levels were higher than the reference range in both the groups. But group I showed significantly low PTX 3 levels (p-value = 0.032) compared with group II. There was a significant positive relationship between PTX 3 and LDL-c (p = 0.003) in group II.

Conclusion CAD patients on statin therapy have lower vessel wall inflammation compared with patients without statin therapy.
Association of Maternal Medical Comorbidities with Duration of Expectant Management in Patients with Severe Preeclampsia
Authors: Cozzi Gabriella D. , Battarbee Ashley N. , Sanjanwala Aalok R. , Casey Brian M. , Subramaniam Akila
Published: April 2023

Objective This study aimed to estimate the association between number of maternal comorbidities and duration of expectant management and perinatal outcomes in patients with preeclampsia with severe features.

Study Design Retrospective cohort of patients with preeclampsia with severe features delivering live, nonanomalous singletons at 23 to 342/7 weeks' gestation at a single center from 2016 to 2018. Patients delivered for an indication other than severe preeclampsia were excluded. Patients were categorized based on the number (0, 1, or ≥2) of comorbidities present: chronic hypertension, pregestational diabetes, chronic kidney disease, and systemic lupus erythematosus. The primary outcome was proportion of potential expectant management time achieved, that is, days of expectant management achieved divided by total potential expectant management time (days from severe preeclampsia diagnosis to 340/7 weeks). Secondary outcomes included delivery gestational age, days of expectant management, and perinatal outcomes. Outcomes were compared in bivariable and multivariable analyses.

Results Of 337 patients included, 167 (50%) had 0, 151 (45%) had 1, and 19 (5%) had ≥2 comorbidities. Groups differed with respect to age, body mass index, race/ethnicity, insurance, and parity. The median proportion of potential expectant management achieved in this cohort was 1.8% (interquartile range: 0–15.4), and did not differ by number of comorbidities (adjusted β: 5.3 [95% confidence interval [CI]: −2.1 to 12.9] for 1 comorbidity vs. 0 and adjusted β: −2.9 [95% CI: −18.0 to 12.2] for ≥2 comorbidities vs. 0). There was no difference in delivery gestational age or duration of expectant management in days. Patients with ≥2 (vs. 0) comorbidities had higher odds of composite maternal morbidity (adjusted odds ratio: 3.0 [95% CI: 1.1–8.2]). There was no association between number of comorbidities and composite neonatal morbidity.

Conclusion Among patients with preeclampsia with severe features, the number of comorbidities was not associated with duration of expectant management; however, patients with ≥2 comorbidities had higher odds of adverse maternal outcomes.

Key Points
Plasma Kallikrein as a Forgotten Clotting Factor
Authors: Kearney Katherine J. , Spronk Henri M.H. , Emsley Jonas , Key Nigel S. , Philippou Helen
Published: April 2023

For decades, it was considered that plasma kallikrein's (PKa) sole function within the coagulation cascade is the activation of factor (F)XII. Until recently, the two key known activators of FIX within the coagulation cascade were activated FXI(a) and the tissue factor–FVII(a) complex. Simultaneously, and using independent experimental approaches, three groups identified a new branch of the coagulation cascade, whereby PKa can directly activate FIX. These key studies identified that (1) FIX or FIXa can bind with high affinity to either prekallikrein (PK) or PKa; (2) in human plasma, PKa can dose dependently trigger thrombin generation and clot formation independent of FXI; (3) in FXI knockout murine models treated with intrinsic pathway agonists, PKa activity results in increased formation of FIXa:AT complexes, indicating direct activation of FIX by PKa in vivo. These findings suggest that there is both a canonical (FXIa-dependent) and non-canonical (PKa-dependent) pathway of FIX activation. These three recent studies are described within this review, alongside historical data that hinted at the existence of this novel role of PKa as a coagulation clotting factor. The implications of direct PKa cleavage of FIX remain to be determined physiologically, pathophysiologically, and in the context of next-generation anticoagulants in development.
Predictors of Remission of Acromegaly following Surgical Treatment in Growth Hormone-Secreting Pituitary Adenoma
Authors: Konar Subhas , Yeole Ujwal , Shukla Dhaval , Bhat Dhananjaya I. , Sadashiva Nishanth , Devi Bhagavatula Indira
Published: April 2023

Background and Objective Surgery is the treatment of choice for growth hormone (GH)-secreting pituitary adenoma. The remission of random GH depends on various factors. We aimed to evaluate the predictors related to remission of random GH following surgical treatment.

Methods We collected the data retrospectively from the chart review from a single unit of neurosurgery. The diagnostic criteria for remission were a random GH < 1 ng/mL or nadir GH < 0.4 ng/mL after an oral glucose tolerance test.

Results Data from a total of 110 (females 62 [56.4%]) patients were available for follow-up and were analyzed. The mean age was 36.5 years (14–69 years). Vision impairments were seen in 39 (35.5%) patients. The mean duration of symptoms before surgery was 34 months. The mean volume of the tumor was 7.2 mL (0.44–109.8 mL). Knosp grade 3 and 4 tumors were seen in 41.5% of cases. The mean preoperative random GH level was 68.9 ng/mL. Transsphenoidal surgery was done in 107 (97.3%) cases. The gross total resection could be done in 36 (32.7%) cases. At 3 months, 25 (26%) patients had a biochemical remission. In univariable analysis, lower Knosp grade, preoperative GH level < 40 ng/mL, gross total resection, and male gender were associated with remission at 3 months. In regression analysis, preoperative GH and male gender were related to remission at 3 months.

Conclusion The preoperative GH level < 40 ng/mL is associated with higher chances of remission after surgery for GH-secreting pituitary adenoma.
DNA hydrogels for bone regeneration
Authors: Athanasiadou Dimitra , Meshry Nadeen , Monteiro Naara G. , Ervolino-Silva Ana C. , Chan Ryan Lee , McCulloch Christopher A. , Okamoto Roberta , Carneiro Karina M. M.
Published: April 2023

DNA-based biomaterials have been proposed for tissue engineering approaches due to their predictable assembly into complex morphologies and ease of functionalization. For bone tissue regeneration, the ability to bind Ca
2+
and promote hydroxyapatite (HAP) growth along the DNA backbone combined with their degradation and release of extracellular phosphate, a known promoter of osteogenic differentiation, make DNA-based biomaterials unlike other currently used materials. However, their use as biodegradable scaffolds for bone repair remains scarce. Here, we describe the design and synthesis of DNA hydrogels, gels composed of DNA that swell in water, their interactions in vitro with the osteogenic cell lines MC3T3-E1 and mouse calvarial osteoblast, and their promotion of new bone formation in rat calvarial wounds. We found that DNA hydrogels can be readily synthesized at room temperature, and they promote HAP growth in vitro, as characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, atomic force microscopy, and transmission electron microscopy. Osteogenic cells remain viable when seeded on DNA hydrogels in vitro, as characterized by fluorescence microscopy. In vivo, DNA hydrogels promote the formation of new bone in rat calvarial critical size defects, as characterized by micro-computed tomography and histology. This study uses DNA hydrogels as a potential therapeutic biomaterial for regenerating lost bone.
A contrastive study of Chinese and American online complaints
Authors: Wei Ming
Published: April 2023

Speech acts in CMC (Computer Mediated Communication) have been receiving increasing attention in recent years.
This study attempted to make a cross-cultural comparison of Chinese and American online complaints of restaurants from the
perspective of speech act structure in relation to face management. In spite of likeness in the general taxonomy of retrospective
and prospective speech acts between the two corpora, addressivity appeared to be a strong factor affecting how face was managed
in the specific construction of complaints as speech act sets in the Chinese data set, while such a discrepancy was absent from
the American reviews where the face of restaurants and fellow consumers was not handled with much distinction and discretion.
These findings in terms of the level of sensitivity and adaptation to the context seem to imply that the generally-recognized
distinction of high-context vs. low-context between the two cultures is also manifested in online reviews.
An epistemic interpretation of responses to advice resistance on Chinese phone-ins of family problem
counseling
Authors: Peng Zhuo
Published: April 2023

At present, Epistemics is a popular theory in Western conversation analysis, but few scholars investigate the
responses to the advice resistance on phone-ins from the perspective of Epistemics. This paper explores the responses to the
advice resistance on Chinese phone-ins of family problem counseling from the perspective of Epistemics. It is found that when
responding to the caller’s advice resistance, the host often implements two conversation practices, such as maintaining his/her
original higher epistemic status or constructing higher epistemic status in another epistemic domain. These practices are
consistent with the possibility of the host’s knowledge orientation to strong self-confidence in his/her own professional
knowledge but the lack of confidence in the caller’s relevant knowledge. This study can provide enlightenment for the smooth
development of advice interaction on phone-ins of family problem counseling and expand the application scope of Epistemics.
Enhanced the Bi-(Tri-)partite entanglement between three magnons in a cavity magnomechanics system
Authors: Hidki Abdelkader , Ren Ya-long , Lakhfif Abderrahim , El Qars Jamal , Nassik Mostafa
Published: April 2023

We propose a scheme to generate steady-state bipartite and tripartite entanglement in the cavity magnomechanical system, which consists of a microwave (MW) cavity field, three magnons, and a phonon mode. The three magnons are coupled to the MW cavity via the magnetic dipole interaction, and one of them is also coupled to the phonon mode through the magnetostrictive force. By utilizing the nonlinearity of the magnetostrictive force and the cavity-magnon interaction, the three magnons become mutually entangled, and the steady-state of the system displays a genuine tripartite entanglement. We found that there are optimum parameters, including the detunings and the cavity-magnon coupling, which lead to maximum entanglement. Moreover, the entanglement is robust against thermal effects.
Surface morphology evolution of N-polar GaN on SiC for HEMT heterostructures grown by plasma-assisted molecular beam epitaxy
Authors: Huo Lili , Lingaparthi Ravikiran , Dharmarasu Nethaji , Radhakrishnan K , Chan Casimir
Published: April 2023

The surface morphology evolution of N-polar GaN with growth time was investigated and compared with Ga-polar GaN. N-polar GaN directly grown on SiC substrates was found to have slower 3D-to-2D growth transformation and less coalescence than the Ga-polar counterpart, resulting in rougher surface morphology, whereas the AlN nucleation layer accelerated 3D-to-2D transformation, resulting in smoother surface morphology. N-polar GaN was found to have mound-type surface morphology with clustered atomic steps, unlike the regular screw-type dislocation-mediated step-flow growth observed for Ga-polar GaN. This was explained by the lower diffusion of adatoms on the N-polar surface due to its higher surface energy and higher Ehrlich–Schwoebel barrier. In addition, the increased III/V ratio in N-polar GaN growth was found to reduce the surface roughness from 2.4 nm to 1 nm. Without Si doping, the N-polar GaN high electron mobility transistor (HEMT) heterostructures grown under optimized conditions with smoother surface morphologies exhibited a sheet carrier density of 0.91 × 1013 cm−2 and a mobility of 1220 cm2 (V s)−1. With Si δ-doping, the sheet carrier density was increased to 1.28 × 1013 cm−2 while the mobility was reduced to 1030 cm2 (V s)−1. These results are comparable to the state-of-the-art data of plasma-assisted molecular beam epitaxy-grown N-polar GaN HEMT heterostructures on SiC substrates.
The effect of temperature and excitation energy on Raman scattering in bulk
HfS2
Authors: Antoniazzi Igor , Zawadzka Natalia , Grzeszczyk Magdalena , Woźniak Tomasz , Ibáñez Jordi , Muhammad Zahir , Zhao Weisheng , Molas Maciej R , Babiński Adam
Published: April 2023

Raman scattering (RS) in bulk hafnium disulfide (

HfS

2

) is investigated as a function of temperature (5 K − 350 K) with polarization resolution and excitation of several laser energies. An unexpected temperature dependence of the energies of the main Raman-active (A

1g

and Eg) modes with the temperature-induced blueshift in the low-temperature limit is observed. The low-temperature quenching of a mode ω
1 (134 cm−1) and the emergence of a new mode at approx. 184 cm−1, labeled Z, is reported. The optical anisotropy of the RS in

HfS

2

is also reported, which is highly susceptible to the excitation energy. The apparent quenching of the A

1g

mode at T = 5 K and of the Eg mode at T = 300 K in the RS spectrum excited with 3.06 eV excitation is also observed. We discuss the results in the context of possible resonant character of light-phonon interactions. Analyzed is also a possible effect of the iodine molecules intercalated in the van der Waals gaps between neighboring

HfS

2

layers, which inevitably result from the growth procedure.
Temperature-insensitive high sensitivity refractive index sensor based on tapered no core fiber
Authors: Lu Zhiqi , Liu Changning , Ren Jie , Chen Li , Li Chi , Zhou Wenbiao
Published: April 2023

This study fabricated an ultra-high refractive index (RI) sensor based on tapered no-core fiber (NCF) involving a simple inexpensive process. A splice section of NCF in the middle of single mode fiber was tapered to small diameters. The sensor was sensitive to the surrounding RI with a large measurement range of 1.3330–1.4437. The RI sensitivity differed with varying wavelengths, with a value of 41 916 nm/RIU at approximately 1550 nm, for the RI ranges of 1.4407–1.4437. It yielded a low temperature sensitivity of 8 pm °C−1, which indicates an ultra-low temperature cross-sensitivity. The proposed fiber optic RI sensor can be used in many fields such as medicine and biochemical applications.
On the distinct differences in autonomic regulation between pregnant and non-pregnant women - a heart rate variability analysis
Authors: Bester M , Joshi R , Mischi M , van Laar JOEH , Vullings R
Published: April 2023

Objective. Appropriate adaptation of the maternal autonomic nervous system to progressing gestation is essential to a healthy pregnancy. This is partly evidenced by the association between pregnancy complications and autonomic dysfunction. Therefore, assessing maternal heart rate variability (HRV)—a proxy measure for autonomic activity—may offer insights into maternal health, potentially enabling the early detection of complications. However, identifying abnormal maternal HRV requires a thorough understanding of normal maternal HRV. While HRV in women of childbearing age has been extensively investigated, less is known concerning HRV during pregnancy. Subsequently, we investigate the differences in HRV between healthy pregnant women and their non-pregnant counterparts. Approach. We use a comprehensive suite of HRV features (assessing sympathetic and parasympathetic activity, heart rate (HR) complexity, HR fragmentation, and autonomic responsiveness) to quantify HRV in large groups of healthy pregnant (n = 258) and non-pregnant women (n = 252). We compare the statistical significance and effect size of the potential differences between the groups. Main results. We find significantly increased sympathetic and decreased parasympathetic activity during healthy pregnancy, along with significantly attenuated autonomic responsiveness, which we hypothesize serves as a protective mechanism against sympathetic overactivity. HRV differences between these groups typically had a large effect size (Cohen’s d > 0.8), with the largest effect accompanying the significantly reduced HR complexity and altered sympathovagal balance observed in pregnancy (Cohen’s d > 1.2). Significance. Healthy pregnant women are autonomically distinct from their non-pregnant counterparts. Subsequently, assumptions based on HRV research in non-pregnant women cannot be readily translated to pregnant women.
Configurational dynamics of flexible filaments in bacterial active baths
Authors: Zhang Chunhe , Xie Chenliang , Feng Wei , Luo Hao , Liu Yanan , Jing Guangyin
Published: April 2023

Biopolymers with microscale length and nanoscale cross-sections subjected to active forces is a common non-equilibrium phenomenon in living creatures. It is therefore crucial to intuitively present and investigate the detailed dynamics of such flexible filaments in an active bath full of living matter. Hence, by introducing fluorescent actin filament into an active suspension of motile bacteria at different number densities in a quasi-two-dimensional chamber, we directly visualize the detailed interaction processes and find that bacteria deform a fluctuating filament by relative motion perpendicular to its principal axis of the filament and straighten a filament by parallel motions. We analyzed the evolution of bending energy in dilute and dense bacterial baths with gradual compact or coiled shapes. We successfully introduce a dimensionless number

μ
˜

, named as active elasto-viscous number, which governs the generic deformation of filaments in the bacterial baths by comparing the viscous force generated in the bacterial active baths to the elastic restoring force of filaments. The persistence length measuring the tangential correlation of the flexible filament is found to be proportional to

μ
˜

. Finally, an effective temperature of the bacterial bath is given through the relation between constant stiffness and loading forces instead of the popularly used Einstein relation. Our findings provide detailed information and specific scaling of flexible filaments interplay with active forces and in response to living and crowded environments.
Superfluid dark matter around black holes
Authors: De Luca Valerio , Khoury Justin
Published: April 2023

Superfluid dark matter, consisting of self-interacting light particles that thermalize and condense to form a superfluid in galaxies, provides a novel theory that matches the success of the standard ΛCDM model on cosmological scales while simultaneously offering a rich phenomenology on galactic scales. Within galaxies, the dark matter density profile consists of a nearly homogeneous superfluid core surrounded by an isothermal envelope. In this work we compute the density profile of superfluid dark matter around supermassive black holes at the center of galaxies. We show that, depending on the fluid equation of state, the dark matter profile presents distinct power-law behaviors, which can be used to distinguish it from the standard results for collisionless dark matter.
Multi-frequency, megawatt-power gyrotron to facilitate a wide range of operations at ITER
Authors: Ikeda Ryosuke , Shinya Takahiro , Yajima Satoru , Nakai Taku , Ohgo Takeru , Tsuneyama Masayuki , Yamazaki Hibiki , Kobayashi Takayuki , Kajiwara Ken
Published: April 2023

High-power (1 MW), long-pulse operations up to 300 s were demonstrated by multi-frequency oscillations at 170 GHz, 137 GHz, and 104 GHz. A multi-frequency gyrotron based on the design of the ITER gyrotron has been developed and studied. By redesigning the built-in mode convertor and internal mirrors of the ITER gyrotron, the internal scattered power of the gyrotron was reduced while maintaining the same output beam size and beam direction for the three frequencies. In addition, the mirrors of a matching optics unit were designed to efficiently couple the RF beam at 170 GHz, 137 GHz, and 104 GHz oscillations to a waveguide 50 mm in diameter, the same size that will be used in ITER. An HE
11 mode content of ∼94% was achieved for the three frequencies. Output powers of 1 MW at 170 GHz and 137 GHz, and 0.9 MW at 104 GHz were demonstrated up to 300 s. These oscillation frequencies can facilitate in a wide range of toroidal magnetic field operations at ITER, including plasma start-up and electron heating and current drive.
Leakage Protection of Low Voltage TN-C System Based on Characteristic Currents Amplitude Ratio
Authors: Sun Rongke , Gong Huichang
Published: April 2023

With the repeated grounding of the PEN line, load fluctuation, and other factors, there is no available leakage protection for the low-voltage TN-C system, which is very dangerous when a leakage fault occurs. And TN-C grounding mode is still widely used, and the reformation is slow. The single-phase leakage fault and load fluctuation characteristics of the TN-C system are analyzed, and a leakage protection method for the TN-C system based on the amplitude ratio of characteristic currents is proposed. This method takes the amplitude of the residual current sudden change as the starting criterion, and constructs the action criterion according to the amplitude ratio of load current sudden change and residual current’s sudden change, so as to realize the discrimination of leakage fault and load fluctuation. The proposed method can overcome the influence of load fluctuation and other factors, suitable for TN-C systems with high sensitivity and reliability. The effectiveness of the protection is verified by simulation.
Bi-directional Optical Flow-based Feature Point Tracking Method
Authors: Jiang Hao , Chen Li , Cang Naimeng , Wang Shuang
Published: April 2023

In order to improve the robustness of the SLAM system based on the optical flow method, we propose a feature point tracking method with a bi-directional optical flow. The method first couples the forward LK optical flow and the reverse LK optical flow. Then, the feature points are screened and tracked by coupling the bidirectional optical flow. If the screened feature points do not reach the set threshold, they can be supplemented with either Fast points or Harris points. The experimental validation of the above method by VINS-Mono with the EuRoC dataset shows that VINS-Mono using this method significantly improves the accuracy of localization without increasing the running time cost compared with the original VINS-Mono.
High-Gain Transmissive Array Antenna with Broadband Cross-Polarisation Isolation
Authors: Zhang Jing , Liang Jiangang , Zhao Xilai , Lou Jing
Published: April 2023

A transmissive metal unit working in the range of 18 GHz-29 GHz is designed in this paper. This is a three-layer metal circular slit unit with promising cross-polarization isolation properties. A planar lens antenna with a center operating frequency of 28 GHz is designed based on the unit utilizing a phase compensation algorithm. The numerical simulation results show that the antenna can improve the gain of the horn antenna from 22.9 dB to 25.6 dB, which can effectively advance the development of 5G communication technology.
Research on Modeling Method for Excitation System of One Million-Kilowatt Unit in Nuclear Power Plant based on Real-Time Digital Simulation System
Authors: Liu Yanchao , Gu Qiubin , Jiang Yanzhuo , Zhai Changying , Ma Hongxing , Jiang Yi , Li Yan
Published: April 2023

The excitation system is an important link between the generator set and the power grid. It is not only the key system to stabilize the operation of the generator set but also an important element related to the network. The accurate modeling and testing of the excitation system clarify and analyze the characteristics of the system. The traditional simulation software can only simulate the excitation system without the ability to test the control device and protection equipment. However, the real-time digital simulation system (RTDS) can realize real-time closed-loop tests of the hardware, which provides a new means for the excitation system analysis. This paper builds a detailed excitation system model of nuclear power units based on RTDS. The under-excitation limitation model is proposed based on the actual test data. Furthermore, the stability of the stator current limitation is improved by adding restriction conditions. Finally, the excitation system model is validated based on the measured data.
Research and Governance of Power Quality of the Distribution Network Based on Large-Scale Distributed PV Access
Authors: Yu Danwen , Zhang Yan , Wang Qingyu , Su Yongzhi
Published: April 2023

The continuously increasing distributed photovoltaic installations have a great impact on power grid operation, which shows a trend of “local to global development and distribution network to the main network extension”. The situation puts forward higher requirements for power grid power balance, reactive power regulation, and power quality control. Based on the measured data of a regional power grid, this paper analyzes the new problems brought by the large-scale access of distributed photovoltaic to the power quality of distribution network from the aspects of voltage deviation, harmonics, three-phase imbalance, voltage fluctuation, low voltage ride through, and reactive power support in detail. Besides, it describes a series of management and control measures that the local government and grid companies can take to reduce the operation risk of the distribution network against these adverse effects. The purpose is to provide technical guidance for exploring the new mode of distributed photovoltaic grid connection service and regulation operation management in the whole county.
Digital surface morphology modeling of rotary ultrasonic auxiliary grinding spiral bevel gear
Authors: Li Xinrui , Han Jiaying , Jiang Yiqi , Shen Yongli
Published: April 2023

Because the tooth surface micromorphology affects the performance of the gear and the finite element analysis and the grinding process of tooth surface through finite element analysis and simulation is complicated and time-consuming, the paper proposed a three-dimensional (3D) ultrasonic assistant grinding (RUAG) geometric simulation method to discover the micromorphology formation mechanism. Based on the motion path of a single grain, the 3D models of gear blank and the grinder was built. It helps to simulate the RUAG process. The morphologies of the simulated tooth surface were compared under conventional grinding (CG) and RUAG, which was consistent with the practice. It is proved that the geometric simulation method intuitively shows the micro dents on the tooth surface under different grinding parameters. The simulation method is helpful to analyze the surface morphology under different RUAG machining parameters and saves the cost and time of the actual production and processing.
AMB-Supported Flywheel Battery for Electric Tractors: Structure Design and Driving Method
Authors: Liu Bo , Hu Yaobing , Lyu Xujun , Fan Wei , Zheng Kan
Published: April 2023

Active magnetic bearing (AMB) supported flywheel energy system, also called flywheel battery, is a mechanical battery storing kinetic energy in a rotating flywheel disk and has appealing features such as high specific power and energy, short time of charging/discharging, no pollution and long life span. In this paper, we apply AMB-supported flywheel battery as a new type of power battery to electric tractors, which absorbs wasted energy when the electric tractor brakes frequently and provide additional driving energy supplement when the electric tractor face an overload start, a sudden load mutations or field work resistance mutations. The structure design of the AMB-supported flywheel battery is introduced, including the axial/radial magnetic bearing, flywheel disk, the rotor and the motor. The driving method of the whole system is also analyzed. This design provides the reliability guarantee for the innovative application of the AMB-supported energy storage flywheel battery in electric tractors.
Structural Design and Analysis of an Adaptive Manipulator
Authors: Peng Yujie , Bai Jialuo , Chen Huadong , Yang Peijie , Mei Hao
Published: April 2023

In view of the fact that the existing special manipulator is difficult to meet the requirements, and the universal full-drive multi-finger dexterous manipulator has the shortcomings of complex control and relatively poor reliability, this paper designs a manipulator with simple structure, few driving components, strong adaptive ability, and flexible, stable and fast grasp of objects of different complex shapes. The adaptive manipulator underdrive finger adopts a bionic design, which is composed of a rotary wrist joint, condylar MP joint, intermediate PIP joint, and terminal DIP joint, mixed transmission with gear and tendon rope, with the interaction ability of outer rigidity and inner flexibility, which can realize adaptive envelope grasping and pinching.
Study on the Reliability of X-ray Detection of Dissimilar Metal Welded Joints
Authors: Wei Daoxiang
Published: April 2023

Different steel welding joints are widely used in special equipment and often bear the role of high temperature and high pressure, and corrosive media. Because dissimilar steel welded joints are prone to residual stress and defects during welding, cracks may occur during use. Due to the tissue structure of heterogeneous steel and austenite, ultrasonic detection and surface detection methods are poor. This paper puts forward the ray detection method, including artificial defects, using the ray detection method. Detection results show that the heterogeneous steel welding joint internal defects and that the ray detection method has a good detection effect.
Implementation and Precision Analysis of Speed Measurement System for Marine Main Engine
Authors: Chen Kai , Huang Guoxiong , Sun Jiangping
Published: April 2023

The rotational speed of the marine engine plays a critical role in navigation. In practical application, speed measurement was carried out with the help of the centralized control system. In most cases, the speed information would be obtained through a dedicated line, and it would be transmitted to a few special areas, such as the pilot house, the captain’s office, and the controlling center. Consequently, the users could not get the speed information in time, which might increase navigation risk. A speed measurement system independent from the centralized control system of the original engine was proposed and detailed designed in this work. In addition, remote access was realized by network environment configuration. Furthermore, measurement precision was analyzed from theory and experiment. The results indicate that the system works well during long-term operation and the accuracy of measurement meets the requirement. Due to its accuracy and convenience in use, the system can also be widely used in other monitoring situations.
A Pseudo-Differential Capacitive MEMS Accelerometer Analog Front-End Design
Authors: Kong Dameng , Duan Quanzhen
Published: April 2023

Based on the current design and application of the chip and the research status at home and abroad, we proposed a silicon micro-accelerometer analog front-end integrated circuit with high resolution and wide capacitance application range by using SMIC 0.18μm CMOS technology. The circuit is composed of a capacitive readout circuit, a demodulator, and a low-pass filter. To detect the weak capacitive signal, the capacitor readout circuit of this paper adopts the continuous-time voltage mode charge amplifier structure and combines with the signal modulation technology and the optimization of the MOS transistor size to achieve low noise and high resolution. With the application of the signal modulation technology, the low-frequency capacitance sensor signal is shifted from 2-12 kHz to high-frequency 800 kHz. The signal modulation technology modulates the low-frequency capacitive sensor signal of 2~12 kHz at the high frequency of 800 kHz, and the signal is converted into voltage through the capacitive readout circuit. The simulation results show that the designed analog front-end circuit can convert the accelerometer capacitance signal with the frequency of 2~12 kHz, the dynamic capacitance peak is 0.108 pF, and the static capacitance is 10 pF into the expected voltage signal. In addition, the output noise can be as low as 556 nV/√Hz in the capacitive frequency range of the accelerometer, which meets the requirement of 2.5 aF capacitive resolution. Therefore, the silicon micro-accelerometer analog front-end circuit designed in this paper has the characteristics of a wide capacitor application range, low noise, and high resolution, and can be widely used.
Research on cumulative effect and diagnosis method of transformer short-circuit impulse
Authors: Duan MingHui , Liu LiQing , Yao Chuang , Feng JunJi , Ma Xiaoguang , Wei JuFang , Zhang He , Ma Hao
Published: April 2023

After transformers suffer from short-circuit impact, their mechanical performance decreases significantly. This article establishes a two-wire vibration model to represent the coupling between forces and mechanics and analyzes the transient vibration signals of a 400 V transformer during 22 short-circuits impact. To illustrate the cumulative effect of short-circuits, the vibration entropy, and energy ratio of the main vibration frequency and half frequency are adopted. The results show that transient vibration signals of transformer in short-circuits contain half frequency components, such as 25 Hz and 75, etc., and with the increase of the number of short-circuits, plastic deformation exists in insulation material, which leads to the loss of winding clamping pressure, the reduction of natural frequency, and the upsurge of parametric resonance. With the increase of short circuits, the vibration entropy and half-frequency energy ratio increase, and the main frequency energy ratio decreases. After winding completely lose the axial stability, the vibration entropy and half frequency ratio decrease, and the main frequency ratio increases. The conclusion is of great significance to the analysis of the cumulative effect of short circuits on power transformers.
Measurement Method for Wall Crack Size Based on Pixel Ratio
Authors: Luo Xiao , Zhu Hao
Published: April 2023

The identification and measurement of building cracks can reduce the harm caused by accidents to people’s lives. Reducing manual work can improve the efficiency of crack inspection and reduce inspection errors. In this paper, (1) Machine vision with high measurement accuracy and fast response speed is used, the crack contour is extracted by OpenCV splicing, segmentation, morphological processing, and wall cracks can be accurately detected. (2) The crack size is calculated using the pixel ratio algorithm, the image pixel ratio is calculated by the reference object method, and the size of the wall crack is measured. (3) The measurement error is small. In comparing the experimental results and manual measurement, the width measurement error rate is the highest, 0.314%, and the height error rate is the highest, 2.9%. (4) Size information can be displayed to prevent the hazard caused by cracks in advance. So, the system has a good wall crack identification and measurement effect, which reduces labor costs.
A New Piecewise-Compensated Bandgap Reference Circuit with a Trimming Procedure
Authors: Wei H Y , Duan Q Z
Published: April 2023

A new CMOS bandgap reference (BGR) circuit with a piecewise-compensation circuit and a trimming network is proposed and designed to obtain a bandgap reference voltage with a low-temperature coefficient and a high precision, taking into account the effect of non-ideal factors on the results. The proposed piecewise compensation circuit is designed to achieve a constant reference voltage by using a current mirror to mirror the current, combined with a subtractive circuit and an additive circuit to obtain a low-temperature coefficient over an extensive temperature range. The trim network part is used to change the voltage value of the output reference by controlling the magnitude of the resistance value of the resistors connected to the circuit. The design and simulation of the proposed bandgap reference circuit are obtained by using Cadence Spectre simulation by SMIC 0.18 μm CMOS technology. The results indicates that when the power is 3.3 V and the temperature scope is within -40 °C to 125 °C, the output voltage is 1.2 V with the temperature coefficient equal to 0.658 ppm/°C. When the power varies within 3.2 V to 3.4 V, the linear regulating rate is 0.001019 %/V.
Numerical studies on rock breaking of single axe-shaped PDC cutter
Authors: Yao Jianlin , Zhang Wei , Liu Bin
Published: April 2023

For a drill bit, the cutter is the most important part to break the rock. In oilwell drilling, polycrystalline diamond compact (PDC) bit is widely used to shear the rock formation. In this paper, a finite element model with including the axe-shaped PDC cutter and rock formation is developed to study the rock breaking behaviours. Results show that the effect of axe-shaped PDC cutter on rock breaking is better than that of the planar PDC cutter. The front rake angle and face angel play significant role on the axial force but have little influence on the tangential force. In addition, both the tangential force and axial force increase rapidly with increasing the depth of cut.
Ground Fault Detection of Small Resistance Grounding System Based on Improved Phase Current Abrupt Variable Method
Authors: Xu Xianze
Published: April 2023

When a high fault resistance happens in a small resistance ground system, the protection device is simple to be unsuccessful to manage. By analyzing the characteristics of positive, negative currents in the additional state of fault, it is found that the fault detection method constructed only by the phase current increment relationship has risk of misoperation, but relationship among the magnitude of phase current increment can directly reflect the phase of the ground fault. At the same time, the phase location among the fault phase voltage and the current of the unhealthy part and non-fault line is different. Therefore, a ground fault protection method based on the correlation between the phase current increment ratio and the different phase angles of fault phase voltage and current is proposed. We choose the phase with the big phase current mutation as the grounding phase, and affect the fault part by the phase difference between the fault phase voltage and the current of the line. This eliminates the risk of protection maloperation only using the relationship between the size of current increment and protection sensitivity in case of high resistance fault. It can be used for fault phase selection, location, and multi-level protection. The correctness of the way is certificated by simulation.