bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of heat on the performance of stack welded thin sheets of CRNGO electrical steel
Authors: Dharmik Bhushan Y. , Lautre Nitin Kumar
Published: June 2022

An attempt is made to investigate mechanical-microstructural-magnetic properties on the welded Cold Rolled Non-Oriented Electrical steel (CRNGO) sheets. Single 0.5 mm thin sheets susceptible to Tungsten Inert gas (TIG) welding current are stacked and edge welded using a range of welding current from 30 A to 110 A. The influence of weld with varying current is analyzed through various testing for joint performance, micro-hardness, Residual stress, weld seam characterization, Grain size variation and Magnetic property evaluation of post-welded samples. The results showed the variations of micro-hardness varies by 33 HV and 42 HV at the Heat affected zone (HAZ) and Fusion zone (FZ), respectively. The relative residual stress ranged from 26.85 MPa to 127.6 MPa, weld strength ratio is about 42.9%, depth to width ratio varies from 0.446 to 0.527. The ferritic and largest fine grains size of 79.7 μm is transformed to coarse 282 μm in HAZ. The changes of magnetic properties showed a significant increase in core loss and magnetic field strength with decrease in the relative permeability. The study is useful for electric motor industries to generate varieties during stacked welding of transformer core as per the need of the application.
Comparison of patient tolerance and acceptability of magnet-controlled capsule endoscopy and flexible endoscopy in the investigation of dyspepsia
Authors: Tai Foong Way David , Ching Hey Long , Sloan Marion , Sidhu Reena , McAlindon Mark
Published: June 2022

Background and study aims Oropharyngeal intubation during Esophagogastroduodenoscopy (EGD) is uncomfortable, associated with aerosol generation and transmission of airborne microbes. Less-invasive alternatives may be better tolerated. In this study, patient tolerance and acceptability of EGD and transnasal endoscopy (TNE) have been compared with magnet-controlled capsule endoscopy (MACE).

Patients and methods A comparison of MACE with EGD and TNE in the investigation of dyspepsia was performed. Factors affecting patient tolerance and acceptability were examined using the Endoscopy Concerns Scale (ECS) and Universal Patient Centeredness Questionnaire (UPC-Q).

Results Patients were significantly more distressed (scoring least to most distress: 1–10) by gagging (6 vs 1), choking (5 vs 1), bloating (2 vs 1), instrumentation (4 vs 1), discomfort during (5 vs 1) and after (2 vs 1) EGD compared to MACE (all P < 0.0001). Patients were more distressed by instrumentation (5 vs 1) and discomfort during (5 vs 1) TNE compared to MACE (P = 0.001). Patients were more accepting of MACE than EGD and TNE with a UPC-Q score (scoring least to most acceptable: 0–100) lower for EGD (50 vs 98, P < 0.0001) and TNE (75 vs 88, P = 0.007) than MACE, and a post-procedure ECS score (scoring most to least acceptable: 10–100) higher for EGD (34 vs 11, P < 0.0001) and TNE (25 vs 10.5, P = 0.001) than MACE. MACE would be preferred by 83 % and 64 % of patients even if EGD or TNE respectively was subsequently recommended to obtain biopsies in half of examinations.

Conclusions Gagging and choking during instrumentation, the main causes of patient distress during EGD, occurred less during TNE but tolerance, acceptability and patient experience favored MACE.
Prospective multicenter study of the efficacy and safety of cold forceps polypectomy for ≤ 6-mm non-ampullary duodenal low-grade adenomas
Authors: Kanzaki Hiromitsu , Horii Joichiro , Takenaka Ryuta , Nakagawa Hiroyuki , Matsueda Kazuhiro , Tsuzuki Takao , Kita Masahide , Yamasaki Yasushi , Tanaka Takehiro , Iwamuro Masaya , Kawano Seiji , Kawahara Yoshiro , Tomoda Jun , Okada Hiroyuki
Published: June 2022

Background and study aims Because the endoscopic treatment for non-ampullary duodenal adenoma (NADA) has a non-negligible risk of adverse events (AEs), a safe and easy treatment for NADA is desirable. This was a multicenter prospective trial evaluating the efficacy and safety of cold forceps polypectomy (CFP) for diminutive NADAs.

Patients and methods This study was prospectively conducted at six general hospitals and one university hospital. The inclusion criteria were histologic and endoscopic diagnosis of low-grade NADA measuring ≤ 6 mm. A second endoscopy was scheduled for 1 month after CFP. After confirmation of the success of CFP, 6-month and 12-month surveillance endoscopies were scheduled. The primary endpoint was the endoscopic and histologic disease disappearance rates at the 12-month endoscopy.

Results Thirty-nine lesions from 38 patients were prospectively included. Median tumor size at enrollment was 5 mm (range 3–6 mm). There were four cases of remnant lesions at the second endoscopy, and the lesion disappearance rate of single CFP was 89.7 % (35 /39; 95 % confidence interval (CI), 76.9 %–97.9 %). In three cases, complete removal of the lesion was achieved with a single re-CFP, but one case required four repeat CFPs. The lesion disappearance rate at 12-month endoscopy was 97.4 % (38 /39; 95 %CI, 86.8 %–99.5 %). During the follow-up period, no AEs related to CFP were observed.

Conclusions CFP for NADA ≤ 6 mm was safe and effective in this study. This common endoscopic method to remove lesions may be an option for treatment of diminutive NADAs.
Efficacy and safety of endoscopic duodenal stent versus endoscopic or surgical gastrojejunostomy to treat malignant gastric outlet obstruction: systematic review and meta-analysis
Authors: Krishnamoorthi Rajesh , Bomman Shivanand , Benias Petros , Kozarek Richard A. , Peetermans Joyce A. , McMullen Edmund , Gjata Ornela , Irani Shayan S.
Published: June 2022

Background and study aims Malignant disease accounts for up to 80 % of gastric outlet obstruction (GOO) cases, which may be treated with duodenal self-expanding metal stents (SEMS), surgical gastrojejunostomy (GJ), and more recently endoscopic-ultrasound-guided gastroenterostomy (EUS-GE). These three treatments have not been compared head-to-head in a randomized trial.

Methods We searched the Embase and MEDLINE databases for studies published January 2015−February 2021 assessing treatment of malignant GOO using duodenal SEMS, endoscopic (EUS-GE) or surgical (laparoscopic or open) GJ. Efficacy outcomes assessed included technical and clinical success rates, GOO recurrence and reintervention. Safety outcomes included procedure-related bleeding or perforation, and stent-related events for the duodenal SEMS and EUS-GE arms.

Results EUS-GE had a lower rate of technical success (95.3%) than duodenal SEMS (99.4 %) or surgical GJ (99.9%) (P = 0.0048). For duodenal SEMS vs. EUS-GE vs. surgical GJ, rates of clinical success (88.9 % vs. 89.0 % vs. 92.3 % respectively, P = 0.49) were similar. EUS-GE had a lower rate of GOO recurrence based on limited data (P = 0.0036), while duodenal SEMS had a higher rate of reintervention (P = 0.041). Overall procedural complications were similar (duodenal SEMS 18.7 % vs. EUS-GE 21.9 % vs. surgical GJ 23.8 %, P = 0.32), but estimated bleeding rate was lowest (P = 0.0048) and stent occlusion rate was highest (P = 0.0002) for duodenal SEMS.

Conclusions Duodenal SEMS, EUS-GE, and surgical GJ showed similar clinical efficacy for the treatment of malignant GOO. Duodenal SEMS had a lower procedure-related bleeding rate but higher rate of reintervention.
Role of gastric per-oral endoscopic myotomy (G-POEM) in post-lung transplant patients: a multicenter experience
Authors: Ichkhanian Yervant , Hwang Joo Ha , Ofosu Andrew , Li Andrew A , Szvarca Daniel , Draganov Peter V. , Yang Dennis , Alsheik Eva , Zuchelli Tobias , Piraka Cyrus , Mony Shruti , Khashab Mouen A.
Published: June 2022

Background and study aims Gastroparesis post-lung transplant (LTx) can lead to increased risk of gastroesophageal reflux (GER) and accelerated graft dysfunction. We aimed to evaluate the efficacy and safety of gastric per-oral endoscopic myotomy (G-POEM), a promising tool in patients with refractory gastroparesis, for managing refractory gastroparesis and GER in post-LTx patients.

Patents and methods This was a multicenter retrospective study on post-LTx patients who underwent G-POEM for management of gastroparesis and GER that were refractory to standard medical therapy. The primary outcome was clinical success post-G-POEM. Secondary outcomes included the rate of post-G-POEM objective esophageal pH exam normalization, rate of gastric emptying scintigraphy (GES) normalization, technical success, and adverse events.

Results A total of 20 patients (mean age 54.7 ± 14.1 years, Female 50 %) underwent G-POEM at a median time of 13 months (interquartile range 6.5–13.5) post-LTx. All G-POEM procedures were technically successful. Clinical success was achieved in 17 (85 %) patients during a median follow-up time of 8.9 (IQR: 3–17) months post-G-POEM. Overall GCSI and two of its subscales (bloating and postprandial fullness/early satiety) improved significantly following G-POEM. Two patients (10 %) developed post-procedural AEs (delayed bleeding 1, pyloric stenosis 1, both moderate in severity). Post-G-POEM GES improvement was achieved in 12 of 16 patients (75 %). All 20 patients were on proton pump inhibitors pre-G-POEM, as opposed to five post-G-POEM. Post-G-POEM PH study normalization was noted in nine of 10 patients (90 %) who underwent both pre- and post-G-poem pH testing.

Conclusions G-POEM is a promising noninvasive therapeutic tool for management of refractory gastroparesis and GER post-LTx.
Rettungsdienstlich betreute außerklinische Geburten – seltenes Ereignis und Herausforderung zugleich: eine retrospektive Analyse über 5 Jahre in Hamburg
Authors: Hensel Mario , Mallon Anastasia , Paschen Hans-Richard , Tank Sascha , Wenderoth Stephan , Kerner Thoralf
Published: June 2022

Hintergrund Analyse rettungsdienstlich betreuter Geburten in
Hamburg über einen 5-Jahres-Zeitraum.

Methodik Retrospektive Untersuchung aller außerklinischen
Geburten von 2007 bis 2011.

Ergebnisse Insgesamt wurden im Untersuchungszeitraum 103 Kinder
präklinisch geboren, die postnatal gemeinsam mit der Mutter in eine Klinik eingeliefert
wurden. Das entsprach 0,1% aller Geburten und 0,01% aller Rettungsdiensteinsätze. Es gab keine
mütterlichen und kindlichen Todesfälle ≤ 7 Tage postnatal. Ein Neugeborenes (40. SSW) starb 8
Tage postnatal an einer Lungenfehlbildung. Von den Neugeborenen wiesen 24% eine Hypothermie
< 35 °C und 4% eine Hypoglykämie auf. Mütterliche Verletzungen traten seltener auf, wenn
eine Hebamme anwesend war.

Schlussfolgerungen Relevante praktische Erfahrungen können von
Rettungsdienstmitarbeitern aufgrund der Seltenheit präklinischer Geburten nicht erlangt
werden. Dieses Defizit muss durch adäquate Aus- und Fortbildungsmaßnahmen ausgeglichen
werden.
Neue Berufsbilder im Gesundheitswesen: Digitale Kompetenz
Authors: Strehlau Holger
Published: June 2022

Die digitale Transformation erfordert von den Mitarbeitern im medizinischen Bereich spezielle IT-Kenntnisse, die diese in der Regel nicht haben. Der VDE bietet deshalb eine Zusatzqualifikation zu Digital-technischen Assistenten (DTA) und Digital-technischen Fachangestellten (DTF) an.
Energy harvesting by piezo-tires and their life cycle assessment
Authors: Hazeri Somayyeh , Mulligan Catherine N.
Published: June 2022

Piezoelectric materials can convert mechanical energy into electrical energy. These materials have the potential to provide reliable and cost-effective replacements of energy sources. It can ultimately have the potential to reduce fuel costs in vehicles. The use of piezoelectric materials in pneumatic tires enables capturing the waste energy of cars because of deformations in tires. An experimental setup was designed and constructed to simulate the movement and pressure inside the tire of a car. Piezoelectric elements were attached to the external perimeter of the model tire. Based on the experimental results, this method produced 2.31 W for 56 piezo-elements comparable to 2.3 W for 160 piezo-elements found in the literature. The results showed that placing piezoelectric elements on the outer surface of tires has a higher potential in harvesting the waste energy in vehicle tires. The harvested energy has a direct relation with the compressive stress under the contact patch of the tire. In addition, the harvested energy increases by increasing the velocity and applied weight. In addition to the experimental study, the environmental effects of harvesting waste mechanical energy in tires by using piezoelectric materials bonded to tires were evaluated through a life cycle assessment. The results showed that in addition to harvesting some of the waste energy in cars, it contributes a slightly higher environmental load than ordinary tires. Further evaluation of the technology is required to measure the durability and the lifetime of piezoelectric materials.
Strong robustness and high accuracy in predicting remaining useful life of supercapacitors
Authors: Liu Chunli , Li Dezhi , Wang Licheng , Li Liwei , Wang Kai
Published: June 2022

Remaining useful life shows extraordinary function in guiding the timely replacement of supercapacitors that reach the service life limit, which has great significance to the security and stability of the energy storage system. In order to more accurately predict the remaining useful life of supercapacitors so as to ensure the reliability of the whole supercapacitor bank, a temporal convolutional network is used. Among them, a residual block can solve the problems of gradient explosion and gradient disappearance, which are widespread in the recurrent neural network. Early stopping technology is used to avoid overfitting, and the Adam algorithm was used to optimize the process of parameter adjustment of the temporal convolutional network. The stability and accuracy of the model prediction were verified by using the capacity attenuation dataset of supercapacitors under different experimental conditions. Meanwhile, to verify the generalization ability of the model, the datasets of supercapacitors at different working conditions without training are input into the temporal convolutional network model. Simulation shows that the temporal convolutional network model exhibits strong robustness and high accuracy in predicting the remaining useful life of supercapacitors.
Dynamics of a microsphere inside a spherical cavity with Newtonian fluid subjected to periodic contractions
Authors: Castilla R.
Published: June 2022

Mechanical forces on the nucleus of a biological cell can play a significant role in its positioning within the cell. Some models for the migration of the nucleus are based on biochemical signals, which have a very slow response, and others on the mechanical actions of direct pushing–pulling forces, relying on the cytoskeleton and cell contractility. In the present work, hydrodynamic drag forces, produced by the surrounding membrane movement and acting on a spherical model of the nucleus, are numerically investigated. The space distributions of force and drag resistance are estimated by unsteady three-dimensional computational fluid dynamics simulations. These distributions are functions of sphere size and position, and they are fitted to mathematical models. Dynamic simulations are performed using these mathematical models to compute the trajectory of the microsphere under the action of thousands of position-dependent pushing–pulling forces. A characteristic time is estimated by linearization of the equation, and a dynamic simulation is performed with one-dimensional finite differences. With this approach, it takes a few minutes to simulate several hours of nuclear migration. It is shown that in the long term, nuclei tend to migrate to the center of the cell, especially when it is small compared with the cell size. The model presented here, based exclusively on hydrodynamic interaction in a Newtonian fluid, shows that pushing–pulling forces on the nucleus, produced by periodic contractions of the cell membrane, will cause it to migrate to the center of the cell in a manner that is in agreement with experimental observations.
Unified modeling and kinetic analysis of the near-cathode region and hot cathode in atmospheric-pressure arc discharges
Authors: Sun Li , Sun Xian-Pin , Guo Bi-Ying , Zhou Wen , Li Zeng-Yao
Published: June 2022

The near-cathode region plays a crucial role in exploring the transport characteristics of the transition from arc column to the hot cathode in atmospheric-pressure arc discharges because of the existing non-equilibrium phenomena. A one-dimensional unified model, including the near-cathode region and the cathode body, is developed for an argon arc discharge with the tungsten cathode at atmospheric pressure in this paper. The electrostatic model coupled with an external circuit in the near-cathode region is solved based on the implicit particle-in-cell coupled Monte Carlo collision method without any assumptions of thermal or ionization equilibrium or quasi-neutrality. A detailed description of the arc plasma–cathode and cathode–gas interactions is obtained by calculating the nonlinear heat conduction equation in the cathode. It is shown that the space-charge sheath strongly affects particle transport in the near-cathode region and energy transport from arc plasma to the thermionic cathode. The total current density has significant effects on the kinetic characteristics of arc plasma by feedback-like mechanisms. The Joule heating by the external circuit and charged particles deposited into the cathode are dominating mechanisms of energy transfer from the near-cathode region to the cathode, while energy loss by radiation is more significant compared with natural convection.
Interface evolution characteristics of dual droplet successive oblique impact on liquid film
Authors: Bao Minle , Guo Yali , Gong Luyuan , Shen Shengqiang
Published: June 2022

The dynamic characteristics of dual droplet successive oblique impact on a thin liquid film are numerically studied by using the coupled level set and volume-of-fluid model. This three-dimensional model effectively predicts the evolution of crown and crater, which is validated qualitatively and quantitatively by comparing with experimental observations. Some interesting interface features during the collision and coalescence of crowns are revealed in the present simulations, such as the gas cavity, liquid crest, and air gap. In addition, the crater contour takes on different phases with time in the case of dual droplets impact. The evolution characteristics of crater contours in front view and side view have been summarized within a certain time period. Furthermore, the variations of the maximum crater radius in upstream, downstream, and lateral directions as time are quantitatively analyzed. It is found that in the circumferential direction of the crater, the radial kinetic energy of the liquid decreases gradually from the upstream to the downstream direction. This research establishes a foundation for industrial and agricultural applications involving droplet impact.
Prospects for anisotropic superfluidity in a Fermi gas of dysprosium
Authors: Vinogradov V.A. , Karpov K.A. , Platonova M.V. , Turlapov A.V.
Published: June 2022

The possibility of obtaining superfluid phases for a Fermi gas of dysprosium with a magnetic dipole – dipole interaction is discussed. The obstacles and possible solutions are shown. The required phases are similar to the A1 phase and the polar β phase in 3He. It is expected that in dysprosium, the macroscopic properties of the phase will be determined by the symmetry of the pair interactions. It is assumed to observe the kinetics of phase formation and spontaneous choice between two energy-degenerate phases with different projections of the orbital angular momentum.
Entanglement-assisted concatenated quantum codes
Authors: Fan Jihao , Li Jun , Zhou Yongbin , Hsieh Min-Hsiu , Poor H. Vincent
Published: June 2022

Entanglement-assisted concatenated quantum codes (EACQCs), constructed by concatenating two quantum codes, are proposed. These EACQCs show significant advantages over standard concatenated quantum codes (CQCs). First, we prove that, unlike standard CQCs, EACQCs can beat the nondegenerate Hamming bound for entanglement-assisted quantum error-correction codes (EAQECCs). Second, we construct families of EACQCs with parameters better than the best-known standard quantum error-correction codes (QECCs) and EAQECCs. Moreover, these EACQCs require very few Einstein–Podolsky–Rosen (EPR) pairs to begin with. Finally, it is shown that EACQCs make entanglement-assisted quantum communication possible, even if the ebits are noisy. Furthermore, EACQCs can outperform CQCs in entanglement fidelity over depolarizing channels if the ebits are less noisy than the qubits. We show that the error-probability threshold of EACQCs is larger than that of CQCs when the error rate of ebits is sufficiently lower than that of qubits. Specifically, we derive a high threshold of 47% when the error probability of the preshared entanglement is 1% to that of qubits.
On the optimal management of environmental stock externalities
Authors: Xepapadeas Anastasios
Published: June 2022

Following a brief review of the management of environmental externalities under strategic interactions in the traditional temporal domain, results are extended to the spatiotemporal domain. Conditions for spatial open-loop and feedback Nash equilibria, along with conditions for the benchmark cooperative solution, are presented and compared. A simplified numerical example illustrates the spatial patterns emerging at a steady state under Fickian diffusion and dispersal kernels, and the inefficiency of spatially flat emission taxes. This conceptual framework could provide new research areas.
“A geography of names”
Authors: McEnery Tony , Baker Helen
Published: June 2022

We investigate discourses surrounding venereal disease in a wide body of seventeenth-century texts in the one-billion-word Early English Books Online (EEBO) corpus. By combining quantitative methods with close reading of texts within EEBO, we explore whether perceptions of sufferers and responses to the illness itself shifted as the century progressed. In order to uncover the kinds of written works in which references to venereal disease appear, we undertake a genre analysis with the help of genre categories added to the corpus. The analysis shows that at the beginning of the century, references to these diseases were most likely to appear within historical works, while the end of the century witnesses an increase in references to venereal disease in scientific and medical texts.
Survival or death
Authors: Walker Terry , Kytö Merja
Published: June 2022

This quantitative and qualitative study examines the chronological development of the possessive determiners mine, my, thine, and thy in the Early Modern English Medical Texts corpus (EMEMT), focusing on the influence of phonological environment and text category, as well as noting lexical items with which mine and thine commonly occur. The pattern of decline for mine and thine, the phonological context in which they are found, and the collocations identified resemble those found in previous research, but rather than occurring in more formal texts as suggested by previous research, these forms predominantly occur in the more “popular” medical text categories, those with a wider readership, and particularly in texts that are more speech-like in nature (cf. Kytö and Walker 2020).
Developmental changes of ABR wave 5 latency to click and tonal stimulation at different intensities in infants
Authors: Geal-Dor Miriam , Fichman Sveta , Adelman Cahtia
Published: June 2022

Background

The ABR is useful for estimation of hearing thresholds and is considered an objective test since cooperation of the infant is not required. However, wave 5 identification and threshold determination are often based on the audiologist's subjective judgement. The aim of the present study is to describe the developmental changes in ABR wave 5 latency to different stimuli and intensities in infants of different ages.

Materials and methods

Data from the files of 294 normal hearing infants were used in a retrospective analysis. The latency of wave 5 brainstem component of the ABR to click and tonal stimuli at different intensities down to threshold were measured.

Results

The wave 5 latency to click was shorter than for tonal stimuli. Furthermore, the rate at which latency of wave 5 decreased as a function of stimulus intensity was more pronounced over the higher intensities. The shortening of wave 5 latency was also more rapid over the first few months in response to the higher frequencies.

Discussion and conclusions

Latency values obtained were similar to those described in the literature; wave 5 latency for different frequencies followed the tono-topic organization of the cochlea and the decrease in latency followed neural maturation. Further investigation is needed to determine if the latency values at threshold in infants with hearing loss are similar.
End group engineering enabling organic solar cells with high open-circuit voltage
Authors: Zou Yingping , Sun Chaoyuan , Xu Xiang , Zhou Zhixiang , Luo Xiaoyan , Lu Xinhui , Hu Yunbin , Yuan Jun , Xia Xinxin
Published: June 2022

To investigate the influence of thiophene-fused indanone or thieno[3,2-b]thiophene-fused indanone on acceptors, we designed and synthesized three molecules BTP-CC, BTP-TTC and BTP-TC. Impressively, a high open-circuit voltage (V
oc) of 0.98 V was achieved in BTP-CC based device, which is one of the highest values based on A-DA′D-A type acceptors to date. The small ΔE
HOMO (0.05 eV) between PBDB-T and BTP-TTC resulted in the inefficient exciton dissociation and charge transfer. Despite obtaining a relatively high V
oc of 0.95 V, BTP-TTC based organic solar cell (OSC) displayed poor short-circuit current density (J
sc) and efficiency. Compared with BTP-CC and BTP-TTC, BTP-TC exhibited red-shifted absorption and down-shifted energy levels. Benefiting from the increased crystallinity and the stronger intermolecular interaction, the device of PBDB-T:BTP-TC achieved improved charge dissociation, enhanced charge transport and suppressed charge recombination. Eventually, BTP-TC based OSC realized a higher efficiency of 13.57% with V
oc of 0.86 V, J
sc of 22.64 mA cm–2 and fill factor of 0.70. This systematic work provides an approach to improving V
oc and establishes a guideline for developing A-DA′D-A type acceptors with thiophene- or thieno[3,2-b]thiophene-containing end group.
Single β-Ga2O3 microbelt solar-blind photodetector with high specific detectivity, high rejection ratio and fast speed
Authors: Zheng Zhiyao , Liu Kewei , Cheng Zhen , Qiao Baoshi , Chen Xing , Zhou Chang , Yang Jialin , Ai Qiu , Zhu Yongxue , Li Binghui , Liu Lei , Shen Dezhen
Published: June 2022

An ideal solar-blind photodetector should possess high responsivity, low dark current, high speed, high spectral selectivity, high stability and a facile fabrication method. In this work, a high-quality single β-Ga2O3 microbelt photodetector is fabricated through low-pressure chemical vapor deposition and in situ atmospheric pressure annealing techniques. Due to the high quality and low defect density, this device shows a peak responsivity of 9.47 A W−1 at 256 nm, a dark current of 1 pA and an ultrashort fall time of 1.37 μs under 20 V bias. Moreover, an ultrahigh specific detectivity of ∼1014 Jones and an extremely large solar-blind/ultraviolet A rejection ratio of nearly 105 have also been achieved, suggesting the excellent sensitivity and wavelength selectivity of our single β-Ga2O3 microbelt photodetector. Besides that, the β-Ga2O3 microbelt photodetector exhibits excellent mechanical and long-term stabilities. Our findings provide a facile and promising route to develop high performance solar-blind UV photodetectors.
Catastrophic failure of the back facet in watt-level power long wavelength infrared quantum cascade laser
Authors: Yin Ran , Zhang Jin-Chuan , Guo Qiang-Qiang , Zhuo Ning , Zhai Shen-Qiang , Jia Zhi-wei , Liu Jun-Qi , Wang Li-Jun , Liu Shu-Man , Lu Quan-Yong , Liu Feng-Qi , Wang Zhan-Guo
Published: June 2022

Quantum cascade lasers (QCLs) suffer from catastrophic failure caused by serious self-heating, thus limiting their output power and working stability. In this study, we observed a distinctive failure morphology on the back facet of watt-level power QCL emitting at λ ∼ 7.7 µm. The failure was caused by a massive localized current and the channel of the massive current can be observed in the cavity. Because the massive current significantly increased temperature nearby, two burned holes were formed around the channel. A 3D thermal model shows that the back facet is a vulnerable location for failure because light absorption by the high-reflectance metal coating increases the facet temperature significantly. However, the starting point of the massive current has a certain distance from the facet which is the hottest location in the cavity. Therefore, we conduct a hypothesis that the cause of the massive current is thermal strain relaxations induced by temperature gradient. We calculated the positions of the relaxation points and one of them correspond with the failure starting point found experimentally. The strain relaxation damaged the active region, thus leading to the formation of the massive current.
The impact of ion chamber components on k

B,Q
for reference dosimetry in MRgRT
Authors: Navarro Campos Júlia , de Pooter Jacco , de Prez Leon , Jansen Bartel
Published: June 2022

For reference dosimetry in MRgRT, k

B,Q
is used to correct for the impact of the magnetic field on the chamber calibration coefficient. It has been demonstrated that for accurate simulation of k

B,Q
the dead volume (DV) must be considered. This work goes one step further by analysing the contribution of secondary electrons generated in the various chamber components to k

B,Q
. The Farmer-type chamber PTW 30013 geometry was modelled for two different DVs. Monte Carlo simulations were performed for a 60Co source and a 7 MV MRI-linac and the model was validated against measurements. Both parallel (α = 0° or 180°) and perpendicular (α = 90° or 270°) orientations of the chamber and the magnetic (B) field were considered, and several B-field strengths between 0 T and 1.5 T. To study the dose contribution to the reduced volume (RV = cavity — DV) from the secondary electrons produced in certain components of the chamber the labelling of the particles was implemented in the PENELOPE user code PENMAIN. A separate model with each solid component of the chamber modelled as liquid water was used to investigate the impact of material choice on k

B,Q
. Results show that simulated k

B,Q
values agree better with the measured k

B,Q
when the DV is considered. It is demonstrated that small components of the chamber impact k

B,Q
considerably, since the contribution to the RV-dose from the bodies closer to the RV is higher than without B. Moreover, it is seen that the impact to the dose in the RV is reduced when the material of each component is modelled as liquid water. Therefore, chamber design and, to a lesser extent, choice of material affect k

B,Q
, and an accurate geometrical model of the chamber components and its further validation are important for correct calculations of k

B,Q
.
Machine learning enabled fast evaluation of dynamic aperture for storage ring accelerators
Authors: Wan Jinyu , Jiao Yi
Published: June 2022

For any storage ring-based large-scale scientific facility, one of the most important performance parameters is the dynamic aperture (DA), which measures the motion stability of charged particles in a global manner. To date, long-term tracking-based simulation is regarded as the most reliable method to calculate DA. However, numerical tracking may become a significant issue, especially when a plethora of candidate designs of a storage ring need to be evaluated. In this paper, we present a novel machine learning-based method, which can reduce the computation cost of DA tracking by approximately one order of magnitude, while keeping sufficiently high evaluation accuracy. Moreover, we demonstrate that this method is independent of concrete physical models of a storage ring. This method has the potential to be applied to similar problems of identifying irregular motions in other complex dynamical systems.
Lithium battery attenuation estimation method based on curvature analysis and segmented high-order Gaussian fitting
Authors: Xu J , Zu G W , Yu F J , Song S B , Yu Y , Cui C H , Sun D B
Published: June 2022

Lithium battery has been widely used in various areas, and accurate estimation of battery states is vital to efficient and safe application of batteries. Of all the states, life attenuation is essential to batteries. To improve the estimation accuracy of lithium battery life attenuation, a battery attenuation estimation method based on curvature analysis and segmented Gaussian fitting is designed. The designed method firstly utilizes Cardinal spline curve to smooth the battery attenuation curve. Then, a curvature analysis method is used to segment the life attenuation curve into different sections. Then, a least square linear fitting is used to fit the segmented curves. Except the segmented curve with better linear fitting performance, the remaining segmented curves are fitted with high-order Gaussian fitting. Experiments indicates that the designed method can accurately express the characteristics of different battery life stages.
Transmitting-side AC fault ride-through strategy for LCC-CNPC hybrid DC system
Authors: Wang Xin , Zhao Chengyong , Xuan Jiazhuo , Lu Yi
Published: June 2022

The LCC-CNPC hybrid DC power supply technology is more suitable for application scenarios such as distribution network DC transmission, island DC transmission, border guard posts, etc. However, the AC fault at the sending end will interrupt the power transmission of the LCC-CNPC hybrid DC system, which affects the operation of the DC transmission system. This paper proposes a fault ride-through strategy, which can reduce the voltage on the inverter side to different degrees through a set of control strategies such as increasing the modulation ratio of the inverter side, dynamically adjusting the reactive power, and online switching of cascaded modules. This strategy can adapt to different degrees of voltage sag of the AC bus on the rectifier side, and maintain the system power transmission capability after the AC system at the sending end fails. This strategy improves the fault ride-through capability of the LCC-CNPC hybrid DC system. Finally, a simulation model was established on the PSCAD/EMTDC simulation platform, and the effectiveness of the strategy in this article was verified by comparing and analyzing the simulation results of the AC voltage drop at the sending end.
A Novel LED Driving Power Supply with High Power Factor and Low Total Harmonic Distortion
Authors: Liu Kang , Duan Caiwei
Published: June 2022

proposing a new type of LED driving power supply which is based on buck-boost cascade quad and analysing it in this paper. The main circuit topology structure is based on a quadratic buck and a buck-boost converter. They share the same switch through cascading which not only simplify the topology but also control strategy, reducing the cost of the control circuit. Eliminate the input current dead-time problem of the original quadratic buck topology by adopting two-stage cascade structure. The main circuit topology improves the power factor and ameliorates the input current THD as well. Meanwhile, making the duty cycle of the switch operates in a more plausible area. Finally, relevant experiments demonstrate that the theoretical analysis is correct.
Battery storage systems in electric power grid: A review
Authors: Mviri Franck Soleil Mpio
Published: June 2022

Renewable energy within the utility grid has increased during the previous decade. Severe issues have been raised about the dependability, effectiveness, and efficiency of energy infrastructure. Therefore, energy storage devices have considerably enhanced the network’s accuracy and reliability. Battery energy storage systems (BESS) are among the greatest widely used storage solutions because they have several advantages over traditional power sources, including fast and accurate response, flexibility, and predictability. They are regarded as a reasonable alternative to the threat of climate change. This paper provides a comprehensive evaluation of the BESS’s optimum size targets, limitations, methodology, benefits and disadvantages. Furthermore, energy storage technologies and improved application targets have been presented and discussed for greater clarity. This study focuses primarily on BESS deployments, methodologies, and environmental impact. BEES innovations and achievements for electrical networks are also compared to other energy storage technologies. Concerns and obstacles are discussed to offer researchers in BESS a comprehensive picture. Finally, this study provides several essential ideas that economists and practitioners can use to design a fruitful, robust, efficient, and resilient BESS for a brighter and more optimal deployment.
An Analysis of Insulation Defects and Improvements of Opening/Closing Coil
Authors: Wang Guishan , Li Hongkun , Li Yinghong , Huang Songqiang , Zhao Yan
Published: June 2022

The insulation defects in Opening/Closing coil of circuit breaker were studied in this paper by analysing the structure of coil, the current of coil when operating, causes and characteristics of internal defects. The results show that the insulation defects caused as coil manufacturing will produce local overheating or inter-turn short circuit under the operating current. Faulty coil does not affect performances of circuit breaker. However the DC resistance decreases, coil current increases and waveform is abnormal, and the correctness of the analysis was verified by return test and anatomy. Finally, effective protection measures to the Opening/Closing coil of circuit breaker were proposed and a pulse detection method which can effectively detect defects in coils was introduced. The practice shows that the pulse detection method significantly improves the qualified rate of the coil.
Research on Relay Protection and Security Automatic Equipment Based on the Last Decade of Big Data
Authors: Wang Jingjing , Ma Yingxin , Liu Miao , Huang Tianxiao , Xin Guangming , Zhuang Bo
Published: June 2022

The analysis of equipment record, defects and action events of relay protection and security automatic equipment has been carried out in the last decade since the establishment of an electric power company on the basis of relay protection relay protection statistics analysis and operation management module. It can be seen that the growth rate of security and stability control devices is the highest, which is mainly due to the large-scale grid connection of new energy sites; it should strengthen the operation and maintenance of capacitor protection, and stock up spare parts that are prone to frequent defects, such as triggering-power module of capacitor protection for FSC in the severe electromagnetic environment; the number of primary equipment faults and protection actions shows seasonal characteristics, most of which occur in windy, summer thunderstorm weather. The data-driven screening of familial defects, evaluation of operation and maintenance strategy for aged equipment and spare parts management have been actively explored to improve lean management.
Study on Thermal Process and Microstructure & Properties of High Strength Automotive Steel
Authors: Ji Yong , Chen Zhi Wen , Wan Wen
Published: June 2022

This paper studies how the Nb content affected mechanical properties and microstructures of automotive steel processed by quenching and tempering (Q-T) and quenching-partitioning-tempering (Q-P-T) with the help of tensile testers, X-ray diffractometers, scanning electron microscopes, transmission electron microscopes and other equipment. It was demonstrated that when the Nb content remained the same, Agt (total elongation at maximum force), A (elongation after fracture) and R
m·A (the product of strength with ductility) of the steel processed by Q-P-T were higher than those of the steel processed by Q-T; and when the steel was treated by the same thermal process, as the Nb content increased, its R
p0.2 (yield strength) and R
m (tensile strength) would grow, while A
gt, A and R
m·A would rise first and then decline. No matter if treated by Q-T or Q-P-T, the microstructures of the steel containing 0% and 0.03% of Nb separately were always lath martensite and film-like retained austenite located between laths. When processed by Q-P-T, the steel containing 0.03% Nb saw the largest strength-ductility product. This was because Nb could help refine the sizes of the original austenite grain and the lath martensite and precipitate nano-sized NbC; and the Q-P-T process was more effective in thickening the film-like retained austenite in steel and promoting the dispersed precipitation of the NbC.
Analysis of the IGBT Module with Bonding Wire Failure Based on Transient Thermal Impedance
Authors: Gao Jing , Lv Zhirui , Lu Yi , Song Peng , Zhao Yuan , Xu Guangda , Yang Minxiang
Published: June 2022

Insulated gate bipolar transistor(IGBT) modules are widely used in inverters as power switching devices. In actual working conditions, the failure of bonding wires is one of the most common failure modes. In the current device reliability evaluation, the influence of bonding wire failure is ignored, which may easily cause the subsequent evaluation results to deviate from the reality. In this paper, the influence of the gradual failure of the bonding wire on the transient thermal impedance of the device is explored, and the electro-thermal coupling model of the device is constructed. The simulation results show that the transient thermal impedance of the device increases with the gradual failure of the bonding wire. An experimental platform for transient thermal resistance measurement was built to verify the accuracy of the simulation results.
Research about Wire-like Structure Iron Oxide Anode for Lithium-ion Batteries
Authors: Zhao Wenyu
Published: June 2022

Nano scaled iron oxides have attracted much attention as the anode materials of the lithium-ion batteries, because of its high theoretical capacity, high-capacity retention compared with bulk iron oxides and current commercialized graphite anode. Other benefits including rich abundance, environmental friendliness, low cost and even low toxicity even make it possible to be commercialized. However, problems such as the capacity loss over the first cycle and the capacity retention over the long run are still not satisfying. Thus, this work presents wire-like Fe3O4 core-shell NPs, synthesized by MFI method and high temperature annealing, for using as the anode of lithium-ion batteries. And the wire-like core-shell structure of this material was estimated to have a better electrochemical performance by reducing the aggregation particles and providing a stable nanostructure. In addition to the analysis of the characterization tests, analysis on the electrochemical tests was done in this work, including Cyclic voltammogram and galvanostatic charge and discharge. And the wire-like Fe3O4 core-shell NPs was estimated to show a 1000 mAh g−1 over 100 cycles. Furthermore, future work and challenges from the aspect of synthesizing conditions and further modification of wire-like Fe3O4 core-shell NPs were briefly discussed.
Influence of pitch control method of offshore medium speed wind power based on lateral damping strategy on blade vibration
Authors: Wang Dandan , Luo Zhenkun , Peng Engao , Zhang Yongyang
Published: June 2022

The operating conditions of offshore wind turbines are complex due to the coupling effects of wind waves and other factors. The blade is subjected to uneven load for a long time, which not only increases the difficulty of control and causes fatigue damage, but also leads to the vibration of the tower and affects the service life of the wind turbine. This article mainly GH simulation software was used to simulate sea under variable load condition, based on join the lateral damping strategy, by comparing the independent variable pitch and variable pitch unified control method, analyzed the low frequency vibration of blade root and spindle hub, verified the effectiveness and control advantages of the independent variable pitch control method with lateral damping. It provides effective control measures to solve the vibration problems of the unit and improves the operation reliability.
Improvement of Dynamic Reactive Power Characteristics of New-type Condenser by Excitation Parameters
Authors: Wu Meng , Wang Tong , Li Pengli , Wang Yingming , Cai Yupeng , Zhou Jiaxu , Huang Wei
Published: June 2022

The new-type condenser has the capability of dynamic reactive power compensation under subtransient, transient and steady-state, which could effectively solve the problem of insufficient dynamic reactive power reserve under the background of large-scale development of UHVDC transmission. In this paper, the excitation system parameters of the condenser are taken as the research object. First, the basic principle of new-type condenser and the excitation system model are introduced. Then, an effective gain of reactive current is defined as the quantitative index of the dynamic reactive power characteristics of the new-type condenser, and the effect of excitation system parameters on the dynamic reactive power characteristics of new-type condenser is studied by frequency domain trajectory sensitivity analysis. Finally, the simulation model of the condenser grid connected system is built based on PSCAD/EMTDC, the steady-state reactive power output level and transient response characteristics of new-type condenser with different excitation parameters are studied, and the optimization direction of the condenser excitation system parameters is determined. The simulation results show that reducing k
A, k
p, k
D, T
m and increasing k
I
T
D, T
Z are beneficial to improve the steady-state reactive power output of the condenser. Decreasing k
A, k
p, k
D and increasing k
I, T
D, T
m, T
Z are beneficial to improve the transient response characteristics of the condenser.
A Metal Character Enhancement Method based on Conditional Generative Adversarial Networks
Authors: Huang Yubo , Xiang Zhong
Published: June 2022

In order to improve the accuracy and stability of metal stamping character (MSC) automatic recognition technology, a metal stamping character enhancement algorithm based on conditional Generative Adversarial Networks (cGAN) is proposed. We identify character regions manually through region labeling and Unsharpen Mask (USM) sharpening algorithm, and make the cGAN learn the most effective loss function in the adversarial training process to guide the generated model and distinguish character features and interference features, so as to achieve contrast enhancement between character and non-character regions. Qualitative and quantitative analyses show that the generated results have satisfactory image quality, and that the maximum character recognition rate of the recognition network ASTER is improved by 11.03%.