bluuebunny/crossref_metadata_2025 huggingface dataset:
A lightweight CNN model and its application in intelligent practical teaching evaluation
Authors: He Yi , Li Tianli
Published: March 2020

In this paper, we propose a lightweight CNN model. Firstly, we standardize the existing CNN model structure based on the minimum computing unit, and second we apply a parameter control solution to solve the problem of parameter redundancy in the model. At last we build a lightweight nonaligned CNN model. The experimental results show that the model parameters can be reduced by more than 50% when the test error is almost the same. Through deep learning, the proposed model is applied to the practical teaching system to achieve the intelligent evaluation effect of the practical teaching process, while improve the quality and efficiency of teaching.
The construction and practice of computer network course driven by innovative thinking
Authors: Zhou Shan , Lin Longxin , Shu Yan , Xiong Nian
Published: March 2020

In view of the problems existing in the current teaching of computer network technology and application course, this paper introduces the educational concept driven by innovative thinking into the teaching of the course, and puts forward specific teaching reform measures: the teaching method which adopts the engineering application of innovative thinking as the guidance and focuses the problems on the core knowledge points, combining MOOC, SPOC and flipped classroom teaching philosophy, it is student-centered and arouses students’ interest in learning. Practice has proved that the teaching reform has obvious practical effects: students can quickly grasp the basic theory of computer network with more goals, and meanwhile, their practical ability, teamwork ability and innovation ability can be better trained and improved, which is conducive to the cultivation of high-quality innovative talents.
Exploration and practice of training mode of engineering talents based on open online courses
Authors: Liu Shue , Gao Zonghua , Li Dashe
Published: March 2020

As Chinese economy changes from rapid-speed growth to superior-quality development mods, cultivating the talents for the emerging industries must keep up with The Times to make corresponding adjustments, as well as based on information technology, adopting the multi-paradigm training mode to cultivate amounts of the new engineering talents with cross-knowledge system and innovation.This paper discusses how to take advantage of the creative knowledge map of hourglass to rapidly promote students’ professional ability and the cultivation of their innovation in virtue of online courses, and finally comes to an exploration model.
Examining SNS marketing characteristics affecting brand image and repurchase intention
Authors: Joo Jaehun , Kim Chunglo
Published: March 2020

SNS (Social Network Service) marketing which is a promising marketing based social media such as Facebook, Instagram, Twitter, blog, and Youtube is a critical management activity for online advertising, promotion, sales, and demand creation. What kinds of SNS marketing characteristics are antecedents of brand image and repurchase intention. The present study proposes a new research model integrating SNS marketing characteristics, brand image, and customers’ repurchase intention and tests four hypotheses. Finally, the present paper presents academics and practitioners.
Molecular detection of Enterocytozoon bieneusi in farm-raised pigs in Hainan Province, China: infection rates, genotype distributions, and zoonotic potential
Authors: Zhou Huan-Huan , Zheng Xin-Li , Ma Tian-Ming , Qi Meng , Zhou Jing-Guo , Liu Hai-Ju , Lu Gang , Zhao Wei
Published: March 2020

Enterocytozoon bieneusi is a zoonotic fungal pathogen with a high degree of host diversity that can parasitize many animals, including humans. Pigs may play an important role in the epidemiology of E. bieneusi as reservoir hosts. Nevertheless, the genotypes of E. bieneusi in pigs in China remain poorly understood. The aim of this study was to determine the prevalence of E. bieneusi infection amongst pigs raised on farms from four cities of Hainan Province, using nested polymerase chain reaction (PCR) of the partial small subunit of the ribosomal RNA gene, and to identify genotypes of E. bieneusi isolates based on sequence analysis of the ribosomal internal transcribed spacer (ITS) region. Among 188 stool samples, E. bieneusi was detected in 46.8% (88/188). Eight genotypes including four known (EbpA, CS-4, MJ14, and CHG19) and four novel (HNP-I – HNP-IV) genotypes were identified. Using phylogenetic analysis, genotypes EbpA, CS4, CHG19, HNP-III, and HNP-IV were clustered into zoonotic Group 1, while the remaining three genotypes (MJ14, HNP-I, and HNP-II) clustered into Group 10. The high prevalence of zoonotic genotypes of E. bieneusi among pigs suggests that pig farming is a potential source of human infection. Additionally, this is the first identification of genotypes in Group 10 in pigs indicating unique epidemic features of E. bieneusi in pigs in Hainan Province, the southernmost part of China.
A Simplified Ultrasonographic Score for the Prediction of Cytologically Suspicious Thyroid Nodules
Authors: Pagano Loredana , Bisceglia Alessandro , Riganti Fabrizio , Garberoglio Sara , Rossetto Ruth , Bonelli Nadia , Viberti Laura , Pacchioni Donatella , Papotti Mauro , Ghigo Ezio , Maccario Mauro , Garberoglio Roberto
Published: March 2020

Purpose The major aim of ultrasound (US)-based risk stratification systems is to reduce unnecessary thyroid biopsies without losing the ability to recognize nodules with clinically significant malignancy. Each of the classic suspicious features of a thyroid nodule detected on US scan (hypoechoic pattern, microcalcifications, irregular margin, taller than wide shape, irregular vascularization) is significantly independently associated with the probability of malignancy, but none of them has good diagnostic accuracy. Thus, we evaluated the predictive value of a binary score simply based on the combination of these US features, regardless of the specific predictive value of each US feature, against the outcome of suspected malignancy at cytological diagnosis (TIR3 to TIR5 categories by SIAPEC-IAP [TIR+]).

Materials and Methods 1009 thyroid nodules from 1081 patients were considered. The US features of suspicion of all nodules were categorized in 5 binary scores (U1 to U5), each including from 1 to 5 of those features.

Results U2 (at least 2 US suspicious features) was the most balanced predictor of TIR+ (PPV 0.48, NPV 0.93, LR+ 3.05 and LR– 0.24). Weighting the predictivity of the single features did not improve the estimate. Using U2 as the criterion to send nodules to FNAC would have reduced the number of biopsies by 60 % (604 patients) and the false negatives would have only accounted for 41 cases out of 237 TIR+ (17 %) with 39 cases of TIR3 and 2 cases of TIR4, including only 6 malignant nodules on histological examination. U2 performed much better than the ATA recommendations for detecting those nodules, resulting in TIR+ at cytology.

Conclusion This simple and reproducible sonographic score based on 2 US features of suspicion of malignancy has quite a good performance with respect to identifying thyroid lesions categorized by cytology as medium-high risk of malignancy and could allow us to reduce cytology costs for low-risk nodules.
Frage der „NS-Belastung“ und Mitgliedschaften in NS-Organisationen
Authors: Sparing Frank , Baumann Timo , Martin Michael , Fangerau Heiner
Published: March 2020

Dies ist der erste Teil der Studie „Beziehungen ausgewählter Neurophysiologen zum Nationalsozialismus“. Hier werden die nationalsozialistischen Organisationen vorgestellt, in denen Mediziner typischerweise Mitglieder waren. Dies soll den zweiten Teil vorbereiten, in welchem die wichtigen Neurophysiologen Hans Berger, Paul Hoffmann, Richard Jung und Alois E. Kornmüller näher vorgestellt werden.
Harnessing the Phytotherapeutic Treasure Troves of the Ancient Medicinal Plant Azadirachta indica (Neem) and Associated Endophytic Microorganisms
Authors: Kharwar Ravindra N. , Sharma Vijay K. , Mishra Ashish , Kumar Jitendra , Singh Dheeraj K. , Verma Satish K. , Gond Surendra K. , Kumar Anuj , Kaushik Nutan , Revuru Bharadwaj , Kusari Souvik
Published: March 2020

Azadirachta indica, commonly known as neem, is an evergreen tree of the tropics and sub-tropics native to the Indian subcontinent with demonstrated ethnomedicinal value and importance in agriculture as well as in the pharmaceutical industry. This ancient medicinal tree, often called the “wonder tree”, is regarded as a chemical factory of diverse and complex compounds with a plethora of structural scaffolds that is very difficult to mimic by chemical synthesis. Such multifaceted chemical diversity leads to a fantastic repertoire of functional traits, encompassing a wide variety of biological activity and unique modes of action against specific and generalist pathogens and pests. Until now, more than 400 compounds have been isolated from different parts of neem including important bioactive secondary metabolites such as azadirachtin, nimbidin, nimbin, nimbolide, gedunin, and many more. In addition to its insecticidal property, the plant is also known for antimicrobial, antimalarial, antiviral, anti-inflammatory, analgesic, antipyretic, hypoglycaemic, antiulcer, antifertility, anticarcinogenic, hepatoprotective, antioxidant, anxiolytic, molluscicidal, acaricidal, and antifilarial properties. Notwithstanding the chemical and biological virtuosity of neem, it has also been extensively explored for associated microorganisms, especially a class of mutualists called endophytic microorganisms (or endophytes). More than 30 compounds, including neem “mimetic” compounds, have been reported from endophytes harbored in the neem trees in different ecological niches. In this review, we provide an informative and in-depth overview of the topic that can serve as a point of reference for an understanding of the functions and applications of a medicinal plant such as neem, including associated endophytes, within the overall theme of phytopathology. Our review further exemplifies the already-noted current surge of interest in plant and microbial natural products for implications both within the ecological and clinical settings, for a more secure and sustainable future.
Update Breast Cancer 2020 Part 1 – Early Breast Cancer: Consolidation of Knowledge About Known Therapies
Authors: Schneeweiss Andreas , Hartkopf Andreas D. , Müller Volkmar , Wöckel Achim , Lux Michael P. , Janni Wolfgang , Ettl Johannes , Belleville Erik , Huober Jens , Thill Marc , Fasching Peter A. , Kolberg Hans-Christian , Pöschke Patrik , Welslau Manfred , Overkamp Friedrich , Tesch Hans , Fehm Tanja N. , Lüftner Diana , Schütz Florian
Published: March 2020

This review is intended to present the latest developments in the prevention and treatment of early breast cancer. The risk of breast cancer can be increasingly better characterised with large epidemiological studies on genetic and non-genetic risk factors. Through new analyses, the evidence for high-penetrance genes as well as for low-penetrance genes was able to be improved. New data on denosumab and atezolizumab are available in the neoadjuvant situation as is a pooled appraisal of numerous studies on capecitabine in the curative situation. There is also an update to the overall survival data of pertuzumab in the adjuvant situation with a longer follow-up observation period. Finally, digital medicine is steadily finding its way into science. A recently conducted study on automated breast cancer detection using artificial intelligence establishes the basis for a future review in clinical studies.
A Comparative Study of Health Anxiety in Neurology and Psychiatry Settings
Authors: Prabha Lakshmi , Ganjekar Sundarnag , Gupta Vivek , Desai Geetha , Chaturvedi Santosh K.
Published: March 2020

Objectives Prevalence of health anxiety is highly varied based on different settings and samples studied. This study aimed to assess the prevalence of health anxiety among outpatients attending neurology and psychiatry outpatient setting in tertiary care hospital and understand the clinical correlates.

Participants and Methods This was a cross-sectional study conducted in the outpatient settings including participants fulfilling study criteria. The assessments included semi-structured proforma for demographic and clinical details, general hypochondriasis subscale of Illness Behavior Questionnaire, and Short Health Anxiety Inventory. Data were collected in Epi-info and data analysis was done using STATA12.

Results The health anxiety was reported to be 25% and 19% among psychiatry and neurology outpatients, respectively. Higher education level positively correlated with health anxiety. Skilled workers tend to have higher health anxiety than semiskilled workers. Patients with diagnosis of somatoform disorder and multiple diagnosis scored higher on health anxiety in both the settings.

Conclusion Health anxiety appears to be common in psychiatry and neurology settings and needs further evaluation to understand its impact on consultation and health resource usages.
Potential for Increased Epilepsy Awareness: Impact of Health Education Program in Schools for Teachers and Children
Authors: Murthy Meena Kolar Sridara , Rajaram Prakashi , Mudiyanuru Kannappa Shetty , Palaniappan Marimuthu , Govindappa Lakshmana , Dasgupta Madhuporna
Published: March 2020

Background Epilepsy, although a common disorder, yet is highly stigmatized. Under this condition, children with epilepsy are more vulnerable to stigmatization, social isolation, lack of support, and psychological and emotional problems. Thus, there is an immediate need of literature focusing on intervention studies to change the attitudes of school teachers and children.

Methods The study was conducted with the objectives to evaluate knowledge, attitude, and practices (KAP) about epilepsy among school teachers and children; provide educational training program to teachers; and check the efficacy of training program imparted by teacher and trainer.

Results Repeated measure of analysis of variance shows that knowledge (F = 1,134.875, p < 0.001), attitude (F = 2,429.909, p < 0.001), and practice (F = 2,205.122, p < 0.001) are significantly different between pre- and posttests indicated by Pillai’s trace test. Similarly, from the Pillai’s test, knowledge (F = 49.317, p < 0.001), attitude (F = 125.304, p < 0.001), and practice (F = 178.697, p < 0.001) are significantly different among teachers, trainer imparting training to children, and teachers imparting training to children. It is seen that KAP scores significantly differ between two time points and across the three groups. Among all the groups, teachers imparting training to children had high level of practice.

Conclusion Inclusion of health education programs in the textbooks and health education schemes for teachers and school children are crucial ways to bring a change in their attitude, behavior, and practices toward epilepsy.
When Mount Fuji Can Erupt after Seven Days: A Case Report of Delayed Posttraumatic Tension Pneumocephalus with Literature Review
Authors: Rajan V. T. T. , Dharini G. Krrithvi , Anand V. S. Sathish , Nandish H. S.
Published: March 2020

Tension pneumocephalus (TPC) is a neurosurgical emergency that occurs when there is an expansion of trapped intracranial gas causing raised intracranial pressure. Rarely, posttraumatic TPC can occur even after 72 hours although the initial scans are normal. There are less than 20 cases of delayed TPC in the reported literature. Here, we report a case of delayed TPC that occurred 7 days after the initial injury and presented as sudden neurological deterioration. It was promptly diagnosed with a computed tomography brain and appropriate surgical intervention was performed and the outcome was good. We also did a literature review of reported cases of delayed TPC and looked out for factors that may predict its occurrence. The occurrence of an episode of cerebrospinal fluid rhinorrhea, followed by worsening of headache and sensorium in a patient with anterior cranial fossa fracture should alert a neurosurgeon to the possibility of delayed TPC.
Role of Interventional Radiologist in the Management of Acute Pulmonary Embolism
Authors: Bremer William , Ray Charles E. , Shah Ketan Y.
Published: March 2020

Pulmonary embolism is a common cause of morbidity and mortality which continues to increase in overall incidence. Because it can occur with a wide range of clinical presentations, different guidelines have been developed for appropriate risk stratification of patients; interventional radiology plays a vital role in the management of both massive and submassive pulmonary embolism. Catheter-directed therapy, including mechanical and aspiration thrombectomy, standard catheter-directed thrombolysis, and ultrasound-accelerated thrombolysis, has many benefits, including lower thrombolytic doses and intraclot administration of thrombolytic therapy. While the role of catheter-directed therapy is still being developed, four important prospective studies have demonstrated its safety and efficacy. Additional studies comparing short- and long-term clinical outcomes in patients treated with catheter-directed therapy versus anticoagulation are the next step in understanding its role within the management of submassive pulmonary embolism. Furthermore, multidisciplinary pulmonary embolism response teams, in which interventional radiology plays a crucial role, are becoming essential to appropriately managing pulmonary embolism patients, including selection of those who may benefit from catheter-directed therapy.
Review of CHESS Score in SAH Patients in Local Malaysian Population
Authors: Yee Sze-Voon , Ghani Abdul Rahman , Raffiq Azman
Published: March 2020

Background Chronic hydrocephalus caused by subarachnoid hemorrhage is a reversible and treatable condition. To date, existing clinical scores for predicting the development of posthemorrhagic hydrocephalus are few and difficult to apply in the clinical settings. Chronic hydrocephalus ensuing subarachnoid hemorrhage score (CHESS) was first published in 2016. Although it showed promising results, no external validation has been done outside Europe. We designed this study to validate the accuracy and reliability of CHESS score and to also look for other factors that may cause posthemorrhagic shunt dependent hydrocephalus.

Objectives This study is to determine the reliability of CHESS score and to look for other parameters with predictive value in patients with shunt-dependent posthemorrhagic hydrocephalus.

Results Thirty-one percent of the studied population developed shunt-dependent hydrocephalus (n = 41). CHESS score showed an odds ratio (OR) of 2.184 with p-value < 0.001 and two other risk factors were found to be strongly related to develop shunt-dependent hydrocephalus, that is, early infarct in computed tomography (CT) brain (OR = 0.182; p-value = 0.004) and Fisher’s grade > 3 (OR = 1.986; p-value = 0.047). The sensitivity and specificity for CHESS score in this cohort population showed a sensitivity of 73.2% and specificity of 93.3%. The area under the curve for CHESS score in our cohort is 0.922.

Conclusion CHESS score is a reliable tool in early prediction of shunt-dependent hydrocephalus post subarachnoid hemorrhage.
Pulmonary Complications and Sepsis Following Severe Acute Subdural Hematoma in Patients Who Underwent Craniotomy versus Craniectomy: A Propensity Score Matched Analysis
Authors: Ahmed Nasim , Greenberg Patricia , Shin Seung Hoon
Published: March 2020

Background The purpose of the study was to evaluate the impact of craniotomy (CO) and decompressive craniectomy (DC) for evacuation of acute subdural hematoma (SDH) on pulmonary complications and sepsis.

Methods Study data were obtained from the National Trauma Data Bank (2007–2010). Only patients who met all of the following criteria were included in this analysis: sustained blunt injuries, presented with severe traumatic brain injury, sustained an associated SDH, presented with an initial Glasgow Coma Scale (GCS) score ≤ 8 and an Abbreviated Injury Scale score of head ≥ 3, and underwent a CO or DC within 4 hours of hospital arrival. Patient characteristics and outcomes were compared between CO and DC, the two procedural groups. The data were first compared between the two unmatched groups; then propensity score matching and a matched pairs analysis were performed.

Results From the total population of 2,370 patients, 1,852 (78%) of them underwent CO, and the remaining 518 (22%) underwent DC. Some differences were found between the CO and DC groups regarding age (mean [standard deviation (SD)]: 47.9 years [22.8] versus 39.6 years [20.1]; p < 0.001), sex (male: 70.1% versus 74.7%; p = 0.05), race (white: 77.4% versus 73.4%; p = 0.06), the injury mechanism (fall: 50.7% versus 33.2%; p < 0.001), Injury Severity Score (mean [SD]: 28.0 [9.3] versus 30.5 [10.0]; p < 0.001), and GCS score (median [interquartile range] 3 [3–5] versus 3 [3–4])). After the propensity score matching, no significant differences were found between the groups on the variables just listed (all p > 0.05). No significant differences were seen between the CO and DC groups in the incidences of these conditions: acute respiratory distress syndrome (ARDS) (12.0% versus 8.1%; p = 0.20), pneumonia (34.9% versus 37.6%; p = 0.60), pulmonary embolism (PE) (3.5% versus 1.6%; p = 0.30), and systemic sepsis (6.2% versus 8.1%; p = 0.5).

Conclusion Although most of the patients underwent CO for acute SDH, no significant differences were observed in the incidence of ARDS, pneumonia, PE, or systemic sepsis when compared with patients who underwent DC.
Clinical Course, Imaging Characteristics, and Therapeutic Response in Myelin Oligodendrocyte Glycoprotein Antibody Disease: A Case Series
Authors: James Joe , Jose James , Gafoor V. Abdul , Smita B. , Balaram Neetha , Ramachandran Aparna
Published: March 2020

Myelin oligodendrocyte glycoprotein (MOG) antibody disease is a novel central nervous system autoimmune disorder which forms part of aquaporin 4 (AQP-4) negative, neuromyelitis optica (NMO) spectrum disorder. It has a distinct clinical profile, neuroimaging features and courses from AQP-4 positive NMO and multiple sclerosis. This article is a case series of six patients with MOG antibody disease with longitudinal follow-up for up to 8 months.
Readmission for Early Prosthetic Dislocation after Primary Total Hip Arthroplasty
Authors: Durand Wesley M. , Long William J. , Schwarzkopf Ran
Published: March 2020

Prosthetic dislocation in total hip arthroplasty (THA) is the most common cause for readmission in the 90 days following surgery. This investigation sought to quantify risk factors for readmission for early prosthetic dislocation within 30 days after primary THA. This study used the National Surgical Quality Improvement Program (NSQIP) database for the years 2012 to 2017. The primary outcome was reoperation or readmission for prosthetic dislocation within 30 days after primary total hip replacement. Secondary outcomes included native NSQIP medical complications. A total of 159,234 patients were included. Of these, 0.25% (n = 399) experienced reoperation or readmission for prosthetic dislocation within 30 days postoperatively. A total of 217 dislocated hips (54.4%) returned to the operating room only once, and 27 hips (6.8%) returned to the operating room twice. The mean day of first reoperation/readmission for dislocation was 13.5 (standard deviation [SD]: 9.0). In multivariable logistic regression, the following factors were significantly associated with early reoperation/readmission for prosthetic dislocation: patient age 80+ years (odds ratio [OR]: 1.51 vs. 50–59), high creatinine (OR: 1.75 vs. normal range), smoking (OR: 1.53), history of severe chronic obstructive pulmonary disease (COPD) (OR: 1.73), general anesthesia (OR: 1.41 vs. spinal), American Society of Anesthesiologists (ASA) class 3–5 (OR: 1.66 vs. 1 or 2), fracture (OR: 2.17), chronic steroid use (OR: 1.54), and operative duration ≥ 2 hours (all p < 0.05). Early prosthetic dislocation was significantly associated with the further development of surgical site infection (OR: 2.25) (both p < 0.05). This study identified risk factors for early reoperation/readmission for prosthetic dislocation after THA. These findings have implications for preoperative planning, postoperative management, and dislocation precautions.
Green H2O-Promoted Solvent-Free Synthesis of Enaminocarbonyl Compounds with High Stereoselectivity from Electron-Deficient Terminal Alkynes
Authors: Chen Xiao Yun , Zhang Luming , Tang Yaonan , Yuan Shuxia , Zhu Baocheng , Chen Guang , Cheng Xiaofang
Published: March 2020

A green H2O-promoted solvent-free hydroamination of electron-deficient terminal alkynes with amines has been developed. All secondary amines, including aliphatic and aromatic amines, gave the corresponding (E)-enamines in good to excellent yields, whereas primary aromatic amines afforded Z-configured products in moderate yields. Propiolates, propyn-1-ones, propynamides, and 1-(ethynylsulfonyl)-4-methylbenzene were explored in this Michael addition.
N-Heterocyclic Carbene Catalyzed Deuteration of Aldehydes in D2O
Authors: Sawama Yoshinari , Miki Yuya , Sajiki Hironao
Published: March 2020

An N-heterocyclic carbene (NHC)-catalyzed direct deuteration of aldehydes in a mixed solvent of deuterium oxide (D2O) and cyclopentyl methyl ether was established. The present deuteration is possibly initiated by the formation of a Breslow intermediate from the aldehyde and the NHC, with subsequent trapping by D2O providing the monodeuterated aldehyde.
A fusion algorithm of passive sound source localization based on the two-plane four-element cross array
Authors: Xing Hongyan , Yang Xu , Ji Xinyuan , Wu Hui
Published: March 2020

In this work, a fusion algorithm is proposed for improving the accuracy and stability of passive sound source localization. Different from the traditional algorithm that contains a single-plane cross array, here, the fusion algorithm is used to overcome the position blur in the process of localization. First, the two-plane four-element cross array model is established. Based on this model, the method is defined to judge the position where the sound source is located. According to the localization principle, we derive the calculation formula of the sound source position, based on a single four-element planar array. Then, the elevation angle sine value is introduced into the coordinate formula as the weighted coefficient by analyzing the indirect measurement error, and the fusion algorithm is employed to conduct the sound source localization, based on the two-plane four-element cross array. Finally, the relationships are obtained, between the time delay estimation error, the elevation angle, the horizontal angle, and the localization performance. Besides, the validity of this algorithm is validated by measuring the ranging and direction-finding accuracy. The results show that the distance error rate is within 2%, and the angle error rate is within 3%, which means a good localization effect. The proposed algorithm is expected to be widely used in thunderstorm cloud detection for its quick measurement and high precision.
Linearized theory of terahertz Smith–Purcell radiation from a cylindrical grating loaded with dielectric
Authors: Rezaei Zahra , Farokhi Bizhan
Published: March 2020

An analysis of Smith–Purcell (SP) radiation is presented for a cylindrical grating filled with dielectrics and an annular electron beam propagating along the grating axis. The dispersion relations are obtained for the azimuthally symmetric modes when the transverse perturbation of the electron beam is included, and it is compared with the case when the beam motion is restricted in the z-direction. It is shown that the growth rate changes by the transverse perturbation. The effects of the grating parameter and dielectric constant on the growth rate up to second-order are found. The best parameters of the grating to maximize the growth rate of these modes are also obtained.
Mixing in ICF implosions on the National Ignition Facility caused by the fill-tube
Authors: Weber C. R. , Clark D. S. , Pak A. , Alfonso N. , Bachmann B. , Berzak Hopkins L. F. , Bunn T. , Crippen J. , Divol L. , Dittrich T. , Kritcher A. L. , Landen O. L. , Le Pape S. , MacPhee A. G. , Marley E. , Masse L. P. , Milovich J. L. , Nikroo A. , Patel P. K. , Pickworth L. A. , Rice N. , Smalyuk V. A. , Stadermann M.
Published: March 2020

The micrometer-scale tube that fills capsules with thermonuclear fuel in inertial confinement fusion experiments at the National Ignition Facility is also one of the implosion's main degradation sources. It seeds a perturbation that injects the ablator material into the center, radiating away some of the hot-spot energy. This paper discusses how the perturbation arises in experiments using high-density carbon ablators and how the ablator mix interacts once it enters the hot-spot. Both modeling and experiments show an in-flight areal-density perturbation and localized x-ray emission at stagnation from the fill-tube. Simulations suggest that the fill-tube is degrading an otherwise 1D implosion by ∼2×, but when other degradation sources are present, the yield reduction is closer to 20%. Characteristics of the fill-tube assembly, such as the through-hole size and the glue mass, alter the dynamics and magnitude of the degradation. These aspects point the way toward improvements in the design, some of which (smaller diameter fill-tube) have already shown improvements.
Phase relation between supercooled liquid and amorphous silicon
Authors: Okada Junpei T. , Sit Patrick H.-L. , Ishikawa Ryo , Ishikawa Takehiko , Chen Jinfan , Nakayama Koji S. , Maeda Kensaku , Yokoyama Yoshihiko , Watanabe Yuki , Paradis Paul-François , Watanabe Yasuhiro , Nanao Susumu , Ikuhara Yuichi , Kimura Kaoru , Uda Satoshi
Published: March 2020

The phase relation between supercooled liquid silicon (l-Si) and amorphous silicon (a-Si) is discussed based on experimental results. Electrostatically levitated l-Si samples were supercooled down to low temperatures, 300 K below the melting temperature (Tcl: 1683 K), and solidified accompanied by the release of latent heat. It was found that solidified Si samples melted again at 1480 K caused by the latent heat. Also, it was found that the Si samples that rapidly quenched near the solidification temperature contained a large amount of a-Si with tetrahedral coordination. These two findings show that the supercooled l-Si samples solidified into a-Si and a-Si melted, confirming the idea of a first-order phase transition between two metastable phases proposed by Turnbull et al. [Metall. Mater. Trans. A 29, 1825 (1998)].
A theoretical criterion for the closure of slots filled with low-Z foam
Authors: Liu Zhongheng , Meng Guangwei , Zhao Yingkui
Published: March 2020

Hydrodynamic motion of radiation-ablated high-Z plasma has a significant influence on the radiation transport in a slot. This work focuses on the closure problem of slots filled with low-Z foam of density varying from 10−2 to 100 g cm−3. A simple one-dimensional model is proposed to study the motion of the ablated high-Z wall plasma in the slot. According to the model, the high-Z plasma first expands to the center of the slot, then reverses because of the competition of the ablation pressure with radiation pressure and the thermal pressure of the low-Z foam. The analytical formulas for the maximum values of reverse time and reverse distance of the high-Z plasma are deduced. Based on the relationship between the expansion-reverse movement of the high-Z plasma and the closing-reopening process of the slot, we obtain a criterion of slot closure by comparing the reverse distance of the high-Z plasma xr and the initial width of the slot w. We predict that the slot finally closes when w/2 < xr, while it remains open when w/2 > xr. Our theory is proved to be valid by the results of simulations using the code MULTI.
Development of an MeV proton generator using a 3He ion source at the Research Center for Nuclear Physics
Authors: Yorita Tetsuhiko , Takahisa Keiji , Shima Tatsushi , Fukuda Mitsuhiro , Kanda Hiroki
Published: March 2020

For simple applications, such as the calibration of a charged particle detector, a multi-MeV proton generator may be preferable to cyclotrons or electrostatic accelerators such as Van de Graaff generator. Thus, a proton generating system, consisting of an 18 GHz superconducting (SC)-ECR ion source and a deuterated polyethylene target, was developed at the Research Center for Nuclear Physics at Osaka University. A 3He2+ beam of 400 eμA was generated by the SC-ECR ion source with the acceleration voltage of 20 kV in an experiment that utilized the fusion reaction 3He + deuteron (D) → proton(P) + 4He. Protons with energies of the order of several MeV were successfully generated at 3.67 Hz at the atmosphere side of the target in the experimental setup, using a novel target base with a thin aluminum window.
Improvement of Mott spin polarimeters: An overlooked redundancy
Authors: Fanciulli Mauro
Published: March 2020

In Mott polarimeters, the measurement of the spin polarization of an electron beam along two perpendicular quantization axes is commonly performed by collecting scattered electrons with four independent detectors placed azimuthally at 90° from each other. However, the four intensities are not independent quantities. This overlooked redundancy will be pointed out, and it will be shown how to use it in order to better design, calibrate, and operate Mott polarimeters.
Isomorphism between the R-matrix and Drinfeld presentations of quantum affine algebra: Type C
Authors: Jing Naihuan , Liu Ming , Molev Alexander
Published: March 2020

An explicit isomorphism between the R-matrix and Drinfeld presentations of the quantum affine algebra in type A was given by Ding and Frenkel [Commun. Math. Phys. 156, 277–300 (1993)]. We show that this result can be extended to types B, C, and D and give a detailed construction for type C in this paper. In all classical types, the Gauss decomposition of the generator matrix in the R-matrix presentation yields the Drinfeld generators. To prove that the resulting map is an isomorphism, we follow the work of Frenkel and Mukhin [Sel. Math. 8, 537–635 (2002)] in type A and employ the universal R-matrix to construct the inverse map. A key role in our construction is played by a homomorphism theorem, which relates the quantum affine algebra of rank n − 1 in the R-matrix presentation with a subalgebra of the corresponding algebra of rank n of the same type.
Two-dimensional Si–Ge monolayers: Stabilities, structures, and electronic properties
Authors: Lu Jiating , Zhang Xi , Shen Limeng , Nie Ya , Xiang Gang
Published: March 2020

Si–Ge monolayers (SiGeMLs) with different elementary proportions x (0 < x < 1) were systematically studied for the first time using ab initio calculations in this work. The structural stabilities of the Si1 − xGexML with different symmetries were investigated using phonon spectra, and an infinite miscibility between Si and Ge elements was revealed in 2D honeycomb structures. The simulated scanning tunneling microscope images and Raman and infrared active modes of the Si1 − xGexML were then obtained for structural characterizations. Interestingly, the study of electronic properties revealed previously unreported oscillatory nonlinear dependence of bandgap values on the elementary proportion x in the Si1 − xGexML, which suggests an alternative way for tuning the bandgaps of 2D materials. Additionally, low effective masses (0.008 m0–0.021 m0) of the carriers in the semiconducting Si1 − xGexML were found, which have the potential for high-speed applications. Considering the advantage of their compatibility with current Si-based technology and the trend of miniature electronic devices, the Si1 − xGexML with stable structures and excellent properties would be important for 2D applications based on group IV materials.
Impact of ionization rate on the transmission of electromagnetic wave in realistic plasma
Authors: Ouyang Wenchong , Liu Yanming
Published: March 2020

A self-consistent calculation model of hypersonic fluid and electromagnetic wave (EM) propagation around a vehicle was used for radio frequency (RF) blackout prediction. First, the plasma flow around the RAMC-II vehicle at an altitude of 61 km was calculated using the finite-volume method with a newly developed unstructured grid solver. The electron number density around the RAMC-II vehicle shows good agreement with the flight test data and NASA data. Then, the effect of chemical reaction ionization rate on the plasma flow is studied, which shows that the electron number density decreases with the decrease in the chemical reaction ionization rate. Finally, based on the influence of the chemical reaction ionization rate on plasma flow, the transmission properties of the electromagnetic wave in realistic plasma at different chemical reaction ionization rates were investigated. The numerical results show that the signal loss of EM waves decreases with the decrease in the ionization rate. The ionization rate is reduced by 25 times, and the electromagnetic wave signal loss is reduced by approximately 30 dB. Based on the study, a scheme to reduce the electron number density around the vehicle by reducing the ionization rate of the chemical reaction, thereby reducing the signal loss of the electromagnetic wave, can be considered to mitigate the RF blackout.
Understanding the reduction of the edge safety factor during hot VDEs and fast edge cooling events
Authors: Artola F. J. , Lackner K. , Huijsmans G. T. A. , Hoelzl M. , Nardon E. , Loarte A.
Published: March 2020

In the present work, a simple analytical approach is presented in order to clarify the physics behind the edge current density behavior of a hot plasma entering in contact with a resistive conductor. As has been observed in recent simulations [C. R. Sovinec and K. J. Bunkers, Plasma Phys. Controlled Fusion 61(2), 024003 (2019)], when a plasma comes in contact with a highly resistive wall, large current densities appear at the edge of the plasma. The model shows that this edge current originates from the plasma response, which attempts to conserve the poloidal magnetic flux (Ψ) when the outer current is being lost. The loss of outer current is caused by the high resistance of the outer current path compared with the plasma core resistance. The resistance of the outer path may be given by plasma contact with a very resistive structure or by a sudden decrease in the outer plasma temperature (e.g., due to a partial thermal quench or due to a cold front penetration caused by massive gas injection). For general plasma geometries and current density profiles, the model shows that, given a small change in minor radius (δa), the plasma current is conserved to first order [δIp=0+O(δa2)]. This conservation comes from the fact that total inductance remains constant (δL=0) due to an exact compensation of the change in external inductance with the change in internal inductance (δLext+δLint=0). As the total current is conserved and the plasma volume is reduced, the edge safety factor drops according to qa∝a2/Ip. Finally, the consistency of the resulting analytical predictions is checked with the help of free-boundary MHD simulations.
Real-fluid phase transition in cavitation modeling considering dissolved non-condensable gas
Authors: Yang Songzhi , Habchi Chaouki
Published: March 2020

In this article, a fully compressible two-phase flow model combined with a multi-component real-fluid phase equilibrium solver is proposed for cavitation modeling. The model is able to simulate the dissolving process of non-condensable gas through resolving the real-fluid phase change equations. A three-dimensional cavitating nozzle test is considered to validate the suggested model. The achieved numerical results have been compared to the available x-ray experiments. The results have confirmed that the model can tackle the phase transition phenomena including gas dissolving and homogeneous nucleation processes. Thus, the cavitation inception has been modeled dynamically when the fluid crosses the phase boundary from the single-phase state to the two-phase state and vice versa. The effects of non-condensable gas on the cavitation inception, development, and unsteadiness have been particularly analyzed, based on the large eddy simulations and x-ray experiments. Finally, the encountered challenges are mentioned, aiming at providing recommendations for similar research studies.
Sediment erosion in zero-mean-shear turbulence
Authors: Rastello M. , Michallet H. , Marié J. L.
Published: March 2020

Turbulence plays an evident role in particle erosion that in many practical situations superimposes with the action of a mean flow. In this paper, the turbulence effect on particle erosion is studied under zero-mean flow conditions, by using the turbulence generated by an oscillating grid. The stirring grid is located more than two mesh size away from the particle layer. The zero-mean flow below the grid has been qualified by revisiting the k–ε model of Matsunaga et al. [Fluid Dyn. Res. 25, 147–165 (1999)]. The turbulence efficiency on the settling/resuspension of the particles is quantified for various turbulence intensities, varying the size, the nature of the particles, and their buoyancy relative to the fluid. We find that the concentrations C of eroded particles collapse fairly well onto a single trend for C ≤ 5 × 10−2, when plotted as a function of the ratio between the flux of turbulent kinetic energy at the particle bed location and the particle settling flux. Above, the concentrations saturate, thus forming a plateau. Particle erosion mechanisms have been investigated in terms of competing forces within an “impulse approach.” Horizontal drag vs friction first leads to a horizontal motion followed by a vertical motion, resulting from vertical drag and lift vs buoyancy. Particle erosion occurs when both force balances are in favor of motion for a duration of 0.1–0.3 Kolmogorov time scale.
Characterization of the thermal and solutal Marangoni flows of opposite directions developing in a cylindrical liquid bridge under zero gravity
Authors: Jin Chihao , Sekimoto Atsushi , Okano Yasunori , Minakuchi Hisashi , Dost Sadik
Published: March 2020

Numerical simulations of the thermo-solutal Marangoni convection developing in a Si–Ge liquid bridge of a floating-zone system have been performed under zero gravity. Half of the liquid bridge was considered as the three-dimensional (3D) computational domain. In this system, the solutal Marangoni convection develops in the direction opposite to the thermal Marangoni convection along the free surface in the bridge, i.e., the thermal Marangoni number, MaT, is negative and the solutal Marangoni number, MaC, is positive. Since the SiGe melt is a low-Prandtl number (Pr = 6.37 × 10−3) and high-Schmidt number (Sc = 14.0) liquid, the temperature field is almost independent of the convective flow and the concentration field determines the transport structures. When MaC is larger than −MaT, the concentration pattern is steady and two-dimensional (2D) axisymmetric. When MaC is smaller than −MaT, we predict two kinds of flow transitions with the increase in |MaT|. If MaC is sufficiently large (MaC ≳ 530), as |MaT| increases, the flow changes from a 2D-steady pattern to a 3D-chaotic behavior at moderate |MaT| (1050 ≲ |MaT| ≲ 2800). We also predict that a second transition and an oscillatory rotating flow occur as |MaT| increases further. The flow becomes 3D-steady at smaller MaC (MaC ≲ 360) with no transition, and the azimuthal wavenumber (m) decreases with increasing |MaT|. Furthermore, the thermo-solutal Marangoni convection in this system can be suppressed almost completely when MaC is approximately equal to −MaT (MaC ≈ −MaT) and the flow becomes periodically stable with weak fluctuations.
A flexible and adaptive grid algorithm for global optimization utilizing basin hopping Monte Carlo
Authors: Paleico Martín Leandro , Behler Jörg
Published: March 2020

Global optimization is an active area of research in atomistic simulations, and many algorithms have been proposed to date. A prominent example is basin hopping Monte Carlo, which performs a modified Metropolis Monte Carlo search to explore the potential energy surface of the system of interest. These simulations can be very demanding due to the high-dimensional configurational search space. The effective search space can be reduced by utilizing grids for the atomic positions, but at the cost of possibly biasing the results if fixed grids are employed. In this paper, we present a flexible grid algorithm for global optimization that allows us to exploit the efficiency of grids without biasing the simulation outcome. The method is general and applicable to very heterogeneous systems, such as interfaces between two materials of different crystal structures or large clusters supported at surfaces. As a benchmark case, we demonstrate its performance for the well-known global optimization problem of Lennard-Jones clusters containing up to 100 particles. Despite the simplicity of this model potential, Lennard-Jones clusters represent a challenging test case since the global minima for some “magic” numbers of particles exhibit geometries that are very different from those of clusters with only a slightly different size.
Magnetic water-in-water droplet microfluidics: Systematic experiments and scaling mathematical analysis
Authors: Navi Maryam , Abbasi Niki , Salari Alinaghi , Tsai Scott S. H.
Published: March 2020

A major barrier to the clinical utilization of microfluidically generated water-in-oil droplets is the cumbersome washing steps required to remove the non-biocompatible organic oil phase from the droplets. In this paper, we report an on-chip magnetic water-in-water droplet generation and manipulation platform using a biocompatible aqueous two-phase system of a polyethylene glycol–polypropylene glycol–polyethylene glycol triblock copolymer (PEG–PPG–PEG) and dextran (DEX), eliminating the need for subsequent washing steps. By careful selection of a ferrofluid that shows an affinity toward the DEX phase (the dispersed phase in our microfluidic device), we generate magnetic DEX droplets in a non-magnetic continuous phase of PEG–PPG–PEG. We apply an external magnetic field to manipulate the droplets and sort them into different outlets. We also perform scaling analysis to model the droplet deflection and find that the experimental data show good agreement with the model. We expect that this type of all-biocompatible magnetic droplet microfluidic system will find utility in biomedical applications, such as long-term single cell analysis. In addition, the model can be used for designing experimental parameters to achieve a desired droplet trajectory.
On the diachrony ofgiusto?(‘right?’) in Italian
Authors: Viola Lorella
Published: March 2020

In Italian, the adjectivegiusto(‘right’) has performed the discourse function of response marker since at least 1613 (DELI 2008: 671). In this paper, I argue that the adjective has recently undertaken a new process of discoursivization, defined as the diachronic process that ends in discourse (Ocampo 2006: 317). In particular, I maintain thatgiustomay also serve the function of invariant tag (Andersen 2001), a linguistic item appended to a statement for the purpose of seeking mutual agreement, verification or corroboration of a claim (Millar and Brown 1979). Through diachronic lexicographic, quantitative and qualitative analyses carried out over a range of historical and contemporary dictionaries and language corpora of different varieties, the results will show that, although the use ofgiusto?as invariant tag is currently undocumented, records of such a use are in fact found since 1990. I explore whether there are positive correlations between the use ofright? in English and the use ofgiusto? in real use Italian and AV dialogues.