bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on Properties of X-Ray Detection Film Based on Thallium Doped Cesium Iodide
Authors: Yanbei Yang , Chunhui Tian , Shuang Liu
Published: April 2021

As X-ray detection imaging has a wide range of applications in medicine, industry, public safety, etc., it is of great significance to study its imaging mechanism and improve its imaging performance. Based on the process of X-ray luminescence in the scintillator material, this paper established a simulation model using a microcrystalline column structure to investigate the relationship between the thickness of the detection film and the light conversion efficiency. With the help of the simulation tool MATLAB, the Monte Carlo method was used to simulate the light conversion process of X-ray in the film, and the results were obtained as follows. Under the condition of other parameters unchanged, the luminous efficiency reached the peak value with the increase of the film thickness, and then gradually decreased with the increase of film thickness. The reason why the conversion efficiency in the early stage increases with the increase of the film thickness is that the film is in a saturated state, and increasing the thickness can cause more X-ray particles to be converted. As the film thickness increases, more fluorescent photons are absorbed as they propagate in the film, resulting in a gradual decrease in conversion efficiency. Therefore, an appropriate film thickness can be selected based on the simulation results to obtain the ideal light conversion efficiency.
Study on Life Cycle Management System for Main condensers in Nuclear Power Plant
Authors: Jie Yang , Liang Yuan , Wu Yang , Qiang Qin
Published: April 2021

Daya Bay Nuclear Power Plant has been running for above 20 years. main condensers have begun to run during the commissioning phase before the official commercial operation, so it is imminent to carry out the life cycle management of main condensers combined with demonstration of the operation license extended to 60 years. A life cycle management system for main condensers in nuclear power plant is established in this paper, which is applied to management practices of Daya Bay Nuclear Power Plant.
The experimental investigation of the HPAM/phenolic resin deep profile system in fractured low-permeability reservoirs
Authors: Zhou Wei , Yin Daiyin , Zhou Yazhou
Published: April 2021

The problem of injected water channeling along fractures exists in the process of water injection in fractured low permeability reservoir, aimed at this problem, deep profile control technology applies to plug fractures to improve the recovery of low permeability reservoir. In this paper, partially hydrolyzed polyacrylamide (HPAM) is used as water-plugging/profile-modifying agent and phenolic resin as crosslinker agent. Several profile control systems are tested to find the one which is suitable for fractured low permeability reservoirs. The performances of profile control systems are evaluated, and effects of formation water salinity, that of shearing rate and that of temperature on the performance are studied. Finally, in order to study effects of this profile control system on displacing oil, flowability experiment and core displacement experiment are applied. It shows that with the increase of salinty of prepared water and the increase of the shearing rate, the viscosity of this system decreases. With the increase of temperature, the gelling time shortens, the viscosity increases, but the stability weekens. This kind of profile control system has a good effect on plugging fractures of low permeability cores. After water flooding, this kind of profile control system is injected into cores, the recovery ratio can increase 3.5%. So the profile control system composed of HPAM/ phenolic resin can apply to deep profile control in fractured low permeability reservoir to enhance oil recovery.
Frequency regulation strategy of photovoltaic system based on system identification
Authors: Zhenjie Li , Guangsong Hou , Zhaolong Cheng , Wenhui Niu , Guohua Hu
Published: April 2021

The large-scale grid connection of photovoltaic power generation results in the power system frequency fluctuation and frequency regulation capacity decline, which endangers the dynamic security of power grid frequency. In order to reduce the frequency deviation of power grid and tap the potential of photovoltaic power generation participating in frequency regulation, a control method of photovoltaic power participating in frequency regulation of power grid is proposed in this paper. The maximum allowable power of photovoltaic power is predicted through system identification, and the load shedding rate is determined based on this, and the output power is corrected according to the system frequency deviation to participate in frequency regulation of power grid. The model based on MATLAB Simulation results shows the effectiveness of the proposed method.
Challenges and Opportunities for Touring Industry and New Energy Automobile Industry
Authors: Yang Jun
Published: April 2021

During pandemic, people’s lives are affected dramatically—more than 20 million people have been affected, and most companies have been affected by such virus. However, people may always consider that some industries with inelastic demands such as touring industries and new energy vehicles industries will not be affected by such crisis. By analyzing the data from specific companies, I found the difficulties and opportunities for these industries. For example, touring industry related companies can use several strategies such as promotional strategy and corporate with high-tech companies to tackle with the catastrophe. Besides, electric car industry related companies may set up their technical barriers to boost their sales. From my research, there is no real-inelastic demands for any industries, and the only method for them to survive at any time is always researching new technology and meet customers’ demands.
A Planning Method for Energy Storage System of Integrated Community Energy System Considering Demand Response
Authors: Li Jinghua , Hua Chenbing , Jiang Deyu , Jiang Qian , Wu Kuihua
Published: April 2021

Demand response plays a significant role in peak load shifting, storage capacity configuration and renewable energy utilization. A bi-level planning method for energy storage system of integrated community energy system considering the demand response is proposed in this paper. In the upper level, the investment cost of electrical energy storage and thermal energy storage, operation and maintenance cost and fuel cost of the integrated community energy system, as well as the compensation cost to the energy consumer, are considered; in the lower level, the responded demand of the energy consumer is taken into consideration to minimize the energy bill of the energy consumer. An actual planning for energy storage system of integrated community energy system shows the effectiveness of the proposed method.
Corrosion and protection of island and offshore oil storage tank
Authors: Feng Miaoke , He Kaining , Zhao Yanhong
Published: April 2021

This article is mainly based on the characteristics of the marine environment of islands and coastal seas and the current corrosion problems of storage tanks as well as their main locations, analyse the reasons for their formation and consider the potential safety hazards, so as to propose several effective storage tank corrosion protection methods, which has important positive significance for the long-term development of islands and coastal seas oil storage tanks.
Exploration and Practice of Volume Fracturing Technology of Shale Oil in Dagang Oilfield
Authors: Shun-li Yin , Tian-lin Zhuang , Li-yong Yang , Yun-peng Jia , Xue-wei Liu , Yu Liu , Yu Yan
Published: April 2021

Based on the geological characteristics of the shale oil in the Kong 2 Member of the Cangdong Sag, Dagang Oilfield, and a large number of core experiments and numerical simulations, the displacement and single-stage liquid volume of the fracturing construction were simulated and optimized; in the stratigraphic shale and stratified mixed shale, the reverse mixing mode is adopted, that is, the gel is used for the rock-breaking seam, and then the low-concentration low-damage fracturing fluid system is used to form the complex seam net. Finally, the high-conductivity-producing area near the well is formed by the addition of sand and gel, forming a personalized horizontal well-cut volume fracturing technology in Dagang Oilfield. The application of this technology in shale oil shows that the output of horizontal well is stable after dense cutting volume fracturing, and industrial development can be realized. Microseismic and stable electric field monitoring confirmed the formation of complex network cracks, and achieved significant yield-increasing effects, providing a reference for the efficient exploration and development of China's continental shale oil.
Adsorption properties of modified eggshell on phosphorus in water
Authors: Li Xiuling , Liu Yaqing , Su Lanlan , Xin Lei
Published: April 2021

Modified eggshell adsorbent was prepared with 5% potassium permanganate solution to adsorb phosphorus in simulated wastewater. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) were used to clarify their phosphorus removal mechanisms. Isothermal and kinetic equations were fitted to explain the mechanism of phosphorus adsorption. The results showed that the optimum conditions were as follows: phosphorus concentration of 5 mg·L-1, wastewater pH of 2, adsorbent dosage of 3.5 g, adsorption time of 350 min, phosphorus adsorption rate of modified eggshell was 90.81%, and the experimental results were relatively stable. According to the characterization, the eggshell adsorbent has good crystallinity, irregular surface structure and abundant pore channels，and the main functional groups on the surface are hydroxyl (-OH) and C-H groups, which enhanced the adsorption effect.
Energy Internet Evaluation Index System under the Zero Carbon Goal
Authors: Rui LI
Published: April 2021

At present, the zero-carbon goal has become the common choice of all the world. Driven by the zero-carbon goal, energy system in China will develop to be cleaner and cleaner. In this situation, Energy Internet has become the future development trend of the energy system. Based on the detailed analysis on the development history, the basic connotation and the key features of Energy Internet, an Energy Internet evaluation index system is introduced. This proposed indicator system evaluates Energy Internet from five dimensions, and all the indexes include the qualitative and the quantitative indicators, the process indicators and the result indicators, the technical indicators and the economic indicators. On this basis, an evaluation method is proposed based on the Analytic Hierarchy Process and the Delphi method. The proposed evaluation index system and the evaluation method can provide a good objective evaluation of the development of Energy Internet.
Research on low-carbon power planning with gas turbine units based on carbon transactions
Authors: Yu Lu , Shengyao Shi , Dachi Zhang , Shunqiang Feng , Yuanmei Zhang , Wenyang Xing , Sixian Wang
Published: April 2021

In the context of low carbon economy, introducing carbon trading and developing low-carbon energy generation is an important means to realize low-carbon development of the power system. Because gas power generation has the advantages of high efficiency, low carbon emission and strong peak load capability, the gas generator unit is added to the planning plan and a low carbon power planning model based on carbon trading is established. The goal of the model is to minimize the cost of the system integration. The cost includes investment operation cost and carbon transaction cost. And the natural gas supply constraints and carbon trading constraints are increased in the constraint condition. Finally, the discrete bacterial colony chemotaxis algorithm is adopted to solve this model. Through the model comparison and sensitivity analysis, it is concluded that the addition of gas turbine unit and carbon trading mechanism can optimize the power supply structure, promote the construction of low carbon unit. and realize the conclusion of low carbon emission reduction of power system. And the results verify the effectiveness of the proposed power planning model.
Chemical speciation of phosphorus in surface sediments from a geological phosphorus-rich watershed, South China
Authors: Wang Chensheng , Xue Qianqian , Chen Honghan
Published: April 2021

In order to clarify the distribution characteristics and potentially environmental effect of phosphorus (P) chemical speciation in river sediments from a typical geological P-rich (GPR) watershed, South China. Forty-eight sediment samples collected from the Huangbai River watershed, Yichang city, Hubei province. The levels of TP in Huangbai River wathershed were remarkably higher than those in most Chinese lakes, reservoirs, and river. The Ca-P and Res-P were the two dominant species that accounted for 78.7% and 13.3% of TP, respectively. Based on the sediment quality guideline (SQGs) and background values of Chinese soil and sediment, the majority of the mean TP concentrations in surface sediments were higher than their background values. The unique distribution pattern of P species in the Huangbai River watershed depends on local environment conditions and P sources. These findings improve our understanding of the eutrophication and P cycle in the GPR watershed.
Flüssigkeits- und Volumentherapie mit kristalloiden und kolloidalen Lösungen
Authors: Jedlicka Jan , Jacob Matthias , Chappell Daniel
Published: April 2021

Bevor eine Infusionstherapie initiiert wird, ist zu unterscheiden, was therapiert werden soll: ein intravasaler Volumenmangel oder ein Flüssigkeitsmangel des gesamten Extrazellulärraumes. Danach richten sich die therapeutische Strategie der Flüssigkeits- und Volumentherapie sowie die Auswahl der zu verabreichenden Infusionslösungen, die dieser Beitrag vorstellt.
Effects of endoscopy-related procedure time on musculoskeletal disorders in Japanese endoscopists: a cross-sectional study
Authors: Matsuzaki Ippei , Ebara Takeshi , Tsunemi Mafu , Hatta Yoshifumi , Yamamoto Kojiro , Baba Akemi , Hattori Masashi , Nakamura Masanao , Fujishiro Mitsuhiro
Published: April 2021

Background and study aims There has been little evidence assessing the prevalence of musculoskeletal disorders (MSDs) among endoscopists performing recent diagnostic and therapeutic endoscopic procedures requiring prolonged procedural times. We evaluated the prevalence and identified the risk factors for developing MSDs, focusing on procedural time.

Methods An electronic survey of endoscopists (n = 213) employed at the Nagoya University Hospital and its affiliated hospitals was developed by a multidisciplinary group. 

Results Of the 110 endoscopists (51.6 %) who responded to the survey, eighty-seven endoscopists (79.1 %) had experienced endoscopy-related MSDs during the previous 1 year, and 49 endoscopists (44.5 %) had experienced these MSDs during the previous week. Nineteen endoscopists (17.3 %) reported absence from work due to severe MSDs. The most frequent sites of MSDs were neck, low back, and shoulders. Logistic regression analyses showed that longer upper endoscopic submucosal dissection ESD, (odds ratio: 5.7; 95 %CI: 1.3–25.0), lower ESD (odds ratio 4.9; 95 %CI: 1.1–22.0), and lower gastrointestinal treatment (odds ratio: 5.6; 95 %CI: 2.3–13.3) were significantly associated with the development of MSDs in the low back area. Moreover, longer lower ESD (odds ratio: 5.0; 95 % CI: 1.2–20.2) was a risk factor for symptoms in the left shoulder.

Conclusion This study suggests a correlation between the volume of therapeutic endoscopic procedures including ESD and the risk of MSDs mainly low back area and left shoulder. Managing monthly total endoscopic time, in light of organizational ergonomics, could contribute to minimizing such risks of endoscopy-related MSDs.
Colorectal endoscopic submucosal dissection using the pocket-creation method with single clip traction: a feasibility study
Authors: Nomura Tatsuma , Hayashi Yoshikazu , Morikawa Takaaki , Okada Masahiro , Fukuda Hisashi , Takezawa Takahito , Sunada Keijiro , Lefor Alan Kawarai , Yamamoto Hironori
Published: April 2021

Background and study aims The pocket-creation method (PCM) facilitates dissection of the central part of a tumor. We previously developed the PCM with clip traction (PCM-CT) to facilitate opening the mucosal pocket, which otherwise could become cumbersome. In the present study, we aimed to examine the feasibility of PCM-CT for colorectal endoscopic submucosal dissection (ESD).

Patients and methods PCM-CT was performed on 30 patients with early colorectal tumors from October 2019 to April 2020. PCM-CT allows efficient opening of the mucosal pocket by using the PCM to dissect the center of the lesion and then apply traction with a single clip after making a circumferential mucosal incision.

Results The median specimen major axis length, ESD time, ESD speed, and en bloc resection rate were 48 mm, 84 minutes, 20 mm2/min, and 100 % (30/30), respectively. The success rates for the traction clip and median single-clip-traction time were 100 % (30/30) and 1.5 minutes, respectively.

Conclusions Colorectal ESD using PCM-CT is a simple and promising method.
Overutilization of surgical resection for benign colorectal polyps: analysis from a tertiary care center
Authors: Saade Rayan , Tsang Tyler , Kmeid Michel , Miller David , Fu Zhiyan , Litynski James , Young Patrick , Anderson Joseph C. , Lee Hwajeong , Tadros Micheal
Published: April 2021

Background and study aims Adequate removal of precancerous polyps is an independent factor in colorectal cancer prevention. Despite advances in polypectomy techniques, there is an increasing rate of surgery for benign polyps. We assessed whether surgical resection is properly utilized for benign colorectal polyps.

Patients and methods We identified 144 patients with surgical resection for benign colorectal polyps. Polyp location, size and the indication for and type of surgery were obtained. For the purposes of this analysis, we assumed that gastroenterologists should assess polyp size accurately, endoscopically resect polyps < 2 cm, and treat incompletely excised polyps on follow-up.

Results A total of 118 patients (82 %) were referred to surgery without attempted endoscopic removal. In 26 (22 %) of 118, the macroscopic polyp size was < 2 cm (23 in right, 3 in the left colon) and 18 (15 %; 14 in the right, four in the left colon) were found to have had size overestimation during endoscopy. Twenty-two (15 %) of 144 underwent surgical resection for incomplete endoscopic resection of adenomas (16 in the right, 6 in the left colon); 12 (54.5 %) had a residual polyp size of < 2 cm (10 in the right colon; 2 in the left colon). In-hospital mortality was 0.7 % and morbidity was 20.1 %.

Conclusions Of the patients, 41 % could have potentially avoided surgical intervention (37 polyps < 2 cm and/or size overestimations precluding endoscopic polypectomy and 22 incomplete resections). When including polyps with size ≥ 2 to < 4 cm, the percentage of patients with avoidable surgery reached 80 %. This confirms the need to develop standardized quality metrics for endoscopic polypectomies and for better overall training of endoscopists performing these procedures. Given the risks of surgery, referral to an experienced gastroenterologist should be considered as a first step.
Wide-field endoscopic submucosal dissection for the treatment of Barrett’s esophagus neoplasia
Authors: Omae Masami , Hagström Hannes , Ndegwa Nelson , Vieth Michael , Wang Naining , Vujasinovic Miroslav , Baldaque-Silva Francisco
Published: April 2021

Background and study aims Implementation of endoscopic submucosal dissection (ESD) for the treatment of Barrett’s esophagus neoplasia (BEN) has been hampered by high rates of positive margins and complications. Dissection with wider margins was proposed to overcome these problems, but was never tested. We aim to compare Wide-Field ESD (WF-ESD) with conventional ESD (C-ESD) for treatment of BEN.

Patients and methods This was a cohort study of all ESDs performed in our center during 2011 to 2018. C-ESD was the only technique used before 2014, with WF-ESD used beginning in 2014. In WF-ESD marking was performed 10 mm from the tumor margin compared to 5 mm with C-E.

Results ESD was performed in 90 cases, corresponding to 74 patients, 84 % male, median age 69. Of these, 22 were C-ESD (24 %) and 68 were WF-ESD (76 %). The en bloc resection rate was 95 vs 100 % (ns), the positive lateral margin rate was 23 % vs 3 % (P  < 0.01), the R0 rate was 73 % vs 90 %, and the curative resection rate was 59 % vs 76 % in the C-ESD and WF-ESD groups, respectively, (both P > 0.05). The procedure speed was 4.4 and 2.3 (min/mm) in the C-ESD and WF-ESD groups (P < 0.01), respectively. WF-ESD was associated with less post-operative strictures, 6 % vs 27 % (P = 0.01), with no local recurrence but no significantly reduced risk of metachronous recurrence (Hazard Ratio = 0.46, 95 %CI = 0.14–1.46), during a follow-up of 13.4 and 9.4 months in the C-ESD and WF-ESD cohorts, respectively.

Conclusions WF-ESD is associated with a reduction in positive lateral margins, faster dissection, and lower stricture rates. Further prospective, multicenter studies are warranted to evaluate its role in clinical practice.
Bioengineering strategies to control epithelial-to-mesenchymal transition for studies of cardiac development and disease
Authors: Bannerman Dawn , Pascual-Gil Simon , Floryan Marie , Radisic Milica
Published: April 2021

Epithelial-to-mesenchymal transition (EMT) is a process that occurs in a wide range of tissues and environments, in response to numerous factors and conditions, and plays a critical role in development, disease, and regeneration. The process involves epithelia transitioning into a mobile state and becoming mesenchymal cells. The investigation of EMT processes has been important for understanding developmental biology and disease progression, enabling the advancement of treatment approaches for a variety of disorders such as cancer and myocardial infarction. More recently, tissue engineering efforts have also recognized the importance of controlling the EMT process. In this review, we provide an overview of the EMT process and the signaling pathways and factors that control it, followed by a discussion of bioengineering strategies to control EMT. Important biological, biomaterial, biochemical, and physical factors and properties that have been utilized to control EMT are described, as well as the studies that have investigated the modulation of EMT in tissue engineering and regenerative approaches in vivo, with a specific focus on the heart. Novel tools that can be used to characterize and assess EMT are discussed and finally, we close with a perspective on new bioengineering methods that have the potential to transform our ability to control EMT, ultimately leading to new therapies.
Superlens coupling to object and image: A secondary resonance mechanism to improve single-negative imaging of electromagnetic waves
Authors: Splawinski Marek , Bostock Spencer , Chau Kenneth J. , Markley Loïc
Published: April 2021

Superlens slabs rely on the coherent superposition of multiply reflected evanescent waves to amplify and restore the fine details of an object at the image plane. If a superlens slab is placed in close proximity to a source object and image detector, similar interactions with these external components can introduce resonances outside of the superlens. In this work, we explore the role of external resonances on single-negative slab superlens performance by considering a complete electromagnetic imaging system containing a physical source object and image detector, each modeled as a planar dielectric half-space. In studying the transmission of spectral components that carry real power through this system, we find that resonances outside the lens can have a dramatic impact on single-negative superlens performance. In particular, we find that the resonances external to a μ-negative lens can be used to extend the imaging range beyond the extreme near field and maintain super-resolution even in the presence of loss.
Review: Production of nuclear medicine radioisotopes with ultra-intense lasers
Authors: Sun Zhanliang
Published: April 2021

In the last two decades, there has been a strong research interest in producing radioisotopes with ultra-intense lasers, as an application of laser-driven accelerators in nuclear medicine. Encouraging progress has been obtained in both experiments and simulations. This Review presents the results of several intense studied radioisotopes in detail, i.e., 18F, 11C, 13N, 15O, 99mTc, 64Cu, and 62Cu. As for other less studied radioisotopes, the results are summarized in Sec. II G. The results are listed in Tables I–VII along with laser intensities, maximum ion/photon energies, number of ions/photons per shot, reactions, and laser repetition rates and facilities. For research based on high repetition rate lasers, both single-shot and multi-shot productions are provided for the purpose of comparison. With key technologies implemented in new commissioning ultra-intense lasers, further experiments will definitely help moving this area forward, which will bring the realization of laser-driven radioisotope production closer.
Trapped bosons, thermodynamic limit, and condensation: A study in the framework of resolvent algebras
Authors: Bahns Dorothea , Buchholz Detlev
Published: April 2021

The virtues of resolvent algebras, compared to other approaches for the treatment of canonical quantum systems, are exemplified by infinite systems of non-relativistic bosons. Within this framework, equilibrium states of trapped and untrapped bosons are defined on a fixed C*-algebra for all physically meaningful values of the temperature and chemical potential. Moreover, the algebra provides the tools for their analysis without having to rely on ad hoc prescriptions for the test of pertinent features, such as the appearance of Bose–Einstein condensates. The method is illustrated in the case of non-interacting systems in any number of spatial dimensions and sheds new light on the appearance of condensates. Yet, the framework also covers interactions and thus provides a universal basis for the analysis of bosonic systems.
Oscillatory shear-induced bcc–fcc martensitic transformation in a colloidal suspension with long-range repulsive interactions
Authors: Fiorucci Giulia , Dijkstra Marjolein
Published: April 2021

We perform non-equilibrium Brownian dynamics simulations to investigate the out-of-equilibrium phase behavior of a suspension of charged colloids under external oscillatory shear. We independently vary the frequency f and the maximum strain amplitude γmax of the oscillations and map out an out-of-equilibrium phase diagram in the f–γmax plane. Similar to what has been observed in earlier studies on colloidal hard spheres, we find the formation of a twinned face-centered-cubic phase in a specific range of γmax, which displays a martensitic transition to a body-centered-cubic crystal within half of the oscillation cycle. We provide a comprehensive analysis of these structures and show how the system transforms from one to the other. We also report evidence of a sliding layer phase and a string phase.
Quantifying the effect of polar interactions on the behavior of binary mixtures: Phase, interfacial, and excess properties
Authors: Alkhatib Ismail I. I. , Vega Lourdes F.
Published: April 2021

In this work, polar soft-Statistical Associating Fluid Theory (SAFT) was used in a systematic manner to quantify the influence of polar interactions on the phase equilibria, interfacial, and excess properties of binary mixtures. The theory was first validated with available molecular simulation data and then used to isolate the effect of polar interactions on the thermodynamic behavior of the mixtures by fixing the polar moment of one component while changing the polar moment of the second component from non-polar to either highly dipolar or quadrupolar, examining 15 different binary mixtures. It was determined that the type and magnitude of polar interactions have direct implications on the vapor–liquid equilibria (VLE), resulting in azeotropy for systems of either dipolar or quadrupolar fluids when mixed with non-polar or low polar strength fluids, while increasing the polar strength of one component shifts the VLE to be more ideal. Additionally, excess properties and interfacial properties such as interfacial tension, density profiles, and relative adsorption at the interface were also examined, establishing distinct enrichment in the case of mixtures with highly quadrupolar fluids. Finally, polar soft-SAFT was applied to describe the thermodynamic behavior of binary mixtures of experimental systems exhibiting various intermolecular interactions (non-polar and polar), not only demonstrating high accuracy and robustness through agreement with experimental data but also providing insights into the effect of polarity on the interfacial properties of the studied mixtures. This work proves the value of having an accurate theory for isolating the effect of polarity, especially for the design of ad hoc polar solvents.
Phase-field modeling of wetting and balling dynamics in powder bed fusion process
Authors: Li Lu , Li Ji-Qin , Fan Tai-Hsi
Published: April 2021

In a powder bed fusion additive manufacturing process, the balling effect has a significant impact on the surface quality of the printing parts. Surface wetting helps the bonding between powder and substrate and the inter-particle fusion, whereas the balling effect forms large spheroidal beads around the laser beam and causes voids, discontinuities, and poor surface roughness during the printing process. To better understand the transient dynamics, a theoretical model with a simplified 2D configuration is developed to investigate the underlying fluid flow and heat transfer, phase transition, and interfacial instability along with the laser heating. We demonstrate that the degree of wetting and fast solidification counter-balance the balling effect, and the Rayleigh–Plateau flow instability plays an important role for cases with relatively low substrate wettability and high scanning rate.
Frequency comb-based multidimensional coherent spectroscopy bridges the gap between fundamental science and cutting-edge technology
Authors: Lomsadze Bachana
Published: April 2021

Optical multidimensional coherent spectroscopy (MDCS) has become a powerful and routine technique for studying optical properties of a wide range of materials. However, current implementations of MDCS have spectral resolution and acquisition speed limitations. In this Perspective, I describe how frequency comb technology can be used to overcome the limitations and also show the recent progress that has been made in this field.
Wetting dynamics of a sessile ferrofluid droplet on solid substrates with different wettabilities
Authors: Khan Adnan , Zhang Shi-Ting , Li Qian-Ping , Zhang Hao , Wang Yu-Qiao , Niu Xiao-Dong
Published: April 2021

There are several numerical approaches to define a permanent magnet in terms of mathematical equations, and each approach has progressed since its inception, but still endures some limitations on specific numerical phenomena. This study seeks to propose a novel numerical representation of a permanent magnet without incorporating its effect through boundary conditions, which overcomes the limitations of previous studies and enables us to introduce a magnetic field of desired strength at any location. A self-correcting method is modified to incorporate the magnetic field effects, while a simplified lattice Boltzmann method is utilized to solve the governing equations for flow field and interface. The validity of the proposed method is ensured by simulating some benchmark phenomena with and without the external magnetic field. This study also investigates the wetting dynamics of a sessile ferrofluid droplet deposited on solid substrates with different wettabilities. The influence of uniform and non-uniform magnetic fields on droplet spreading is discussed in detail. It is observed that for a non-uniform magnetic field in vertical direction, the ferrofluid droplet on a hydrophilic surface does not observe the spherical cap approximation unless the magnetic field strength is below saturation magnetization. Moreover, if the magnet is located above, the droplet undergoes large deformations and achieves pointy shapes with sharp tips on less wettable surfaces.
He beam annealing and self-healing of Kr implanted BaWO4 at low temperature
Authors: Wang Liangling , Cui Xiaojun , Wesch Werner , Wendler Elke
Published: April 2021

Damage formation in 370 keV Kr ion-implanted BaWO4 is investigated with Rutherford backscattering spectrometry in channeling mode (RBS/C), performed in a quasi-in situ modus at a cryogenic temperature of 16 K. The obtained results are compared to those for similar experiments done previously at room temperature. The significant differences observed for ion implantation into BaWO4 at these two temperatures can be explained by the mobility of WO3 impurities. Other authors found WO3 to become mobile at temperatures above 240 K. This defect mobility can further account for the strong damage annealing occurring during warming implanted samples from 16 K to room temperature. In this temperature range, only completely amorphized layers remain stable. However, these layers transform into much less damaged layers exhibiting a strong crystalline long-range order during storage at room temperature with time, revealing a kind of self-healing. Another very important finding is the strong damage annealing due to the analyzing He ions during the RBS/C analysis both at 16 K and at room temperature. The analyzing He ions deposit their energy mainly in the electronic system of the target atoms. By applying an analytical thermal spike model, it is shown that the local temperature increase along the trajectory of the analyzing He ions could be responsible for observed damage annealing. The high susceptibility to energy deposition in electronic processes may have implications for any analysis based on energetic electrons. BaWO4 reveals a high radiation resistance at room temperature, which may be relevant for practical application.
The indispensable role of orbital states in studying the magnetism of Mo-doped BaSnO3
Authors: Zhang Yingying , Wang Yanan , Cui Zhangzhang , Wang Jianlin , Huang Haoliang , Fu Zhengping , Lu Yalin
Published: April 2021

The interplay of internal charge and spin degrees of freedom in diluted magnetic semiconductors (DMSs) determines the magnetic, electrical, and optical properties for desired spintronic devices. However, elusive signs in DMSs, such as Curie temperatures far over 300 K, long-range magnetic order at concentrations of magnetic cations of a few percent, temperature-insensitive, and anhysteretic ferromagnetism, challenge our understanding of magnetism in solids. To approach the truth, the magnetism of Mo-doped BaSnO3 was investigated in this work from experiments to density functional theory (DFT) calculations. Electron spin resonance measurements confirm the existence of oxygen vacancies in the samples, and BaMo0.0625Sn0.9375O3−δ, where δ represents the number of oxygen vacancies, displays much weaker ferromagnetism compared to the DFT results without spin–orbit coupling (SOC). Therefore, a small orbital contribution restored in spin–orbit coupling (SOC) was introduced for the partial density of states and band structure calculations. The modified DFT calculations indicate that the increase in oxygen vacancies leads to an obvious reduction of the total density of states (DOS) near Fermi level (EF), lower dispersity of the conduction band, and deep localized states in the bandgap, which help explain the weak ferromagnetism measured in BaMo0.0625Sn0.9375O3−δ containing considerable oxygen vacancies. This study confirms that the contribution of orbital electron states and defects that were ignored in the conventional explanation should be considered to solve the elusive magnetism in diluted magnetic oxides and offers a guide to improve the magnetism.
SPH-FEM simulation of concrete breaking process due to impact of high-speed water jet
Authors: Yu Ran , Dong Xiangwei , Li Zengliang , Du Mingchao , Zhang Qi
Published: April 2021

The process of concrete breaking by a high-speed water jet was simulated in this study based on the coupled method of smoothed particle hydrodynamics and the finite element method. The Riedel–Hiermaier–Thoma constitutive model was adopted to describe the mechanical characteristics of the concrete material. Various impact velocities (250–800 m/s) and jet diameters (1.0–3.0 mm) were simulated to investigate the effect of incident parameters on the dynamic responses and damage behaviors of the concrete material. The simulation results were also verified by water-jet impact experiments. The results show that the model can reproduce the nonlinear behaviors of concrete due to the impact of the water jet, including crack propagation, large deformation of the crushing crater, and penetration. For the constant jet diameter, a critical velocity of water-jet flow is identified. Lateral cracks can be generated inside concrete when the impact velocity exceeds the critical velocity, which can enhance the water-jet capability significantly to damage the concrete. The evolution process of the concrete crushing crater is also obtained. The initial shape of the crushing crater is “ω-shaped” and then gradually transforms into “V-shaped” until being penetrated by the water jet. The section shape of the concrete crushing hole is trapezoidal after penetration. For impact velocity v ranging from 250 to 500 m/s, the size of the concrete crushing hole increases with the increase in v, and the section shape tends to be rectangular. If v exceeds 500 m/s, the size and section shape no longer change significantly. It was also found that the greater the diameter of the water jet, the more the sensitivity of crushing hole size on water-jet velocity.
The atomic structure and dynamics at the CaCO3 vaterite–water interface: A classical molecular dynamics study
Authors: Schuitemaker Alicia , Raiteri Paolo , Demichelis Raffaella
Published: April 2021

Classical molecular and lattice dynamics were applied to explore the structure and dynamics of water on different surfaces of vaterite, the least abundant calcium carbonate polymorph. Surfaces were generated starting from the three possible structural models for vaterite (monoclinic, hexagonal/trigonal, and triclinic) and pre-screened using their surface energies in an implicit solvent. Surfaces with energies lower than 0.55 J/m2 were then run in explicit water. The majority of these surfaces dissolve in less than 100 ns, highlighting the low stability of this phase in abiotic environments. Three stable surfaces were identified; they exhibited only minor structural changes when in contact with explicit water and did not show any tendency to dissolve during 1 µs molecular dynamics simulations. The computed water density profiles show that all these surfaces have two distinct hydration layers. The water residence time at the various calcium sites was computed to be within 0.7 and 20.5 ns, which suggests that specific Ca ions will be more readily available to bind with organic molecules present in solution. This analysis is a step forward in understanding the structure of this complex mineral and its role in biomineralization, as it provides a solid theoretical background to explore its surface chemistry. In particular, this study provides realistic surface models and predicts the effect of water exchange at the surface active sites on the adsorption of other molecules.
Manipulation of CO adsorption over Me1/CeO2 by heterocation doping: Key roles of single-atom adsorption energy
Authors: Murakami Kota , Mizutani Yuta , Sampei Hiroshi , Ishikawa Atsushi , Sekine Yasushi
Published: April 2021

The performance of metal atoms chemically bonded to oxide supports cannot be explained solely by the intrinsic properties of the metals such as the d-band center. Herein, we present an in-depth study of the correlation between metal–oxide interactions and the properties of the supported metal using CO adsorption on Me1 (Fe1, Co1, and Ni1) loaded over CeO2 (111) doped with divalent (Ca, Sr, and Ba), trivalent (Al, Ga, Sc, Y, and La), and quadrivalent (Hf and Zr) heterocations. CO adsorption over Me1 is strongly dependent on the binding energies of Me1. Two factors led to this trend. First, the extent of the Me1–surface oxygen (Me1–O) bond relaxation during CO adsorption played a key role. Second, the d-band center shifted drastically because of charge transfer to the oxides. The shift is related to the oxophilicity of metals. Adsorption energies of Me1 over oxides include the contributions of the factors described above. Therefore, we can predict the activities of Me1 using the strength of anchoring by oxide supports. Results show that smaller ionic radii of the doped heterocations were associated with more tightly bound Me1. This finding sheds light on the possibility of heterocation-doping manipulating the reactivity of the Me1 catalyst based on theoretical predictions.
Ion mobility–mass spectrometry reveals the role of peripheral myelin protein dimers in peripheral neuropathy
Authors: Fantin Sarah M. , Parson Kristine F. , Yadav Pramod , Juliano Brock , Li Geoffrey C. , Sanders Charles R. , Ohi Melanie D. , Ruotolo Brandon T.
Published: April 2021

Significance

The myelin sheath surrounding human neurons acts as insulation and increases their rate of signal transmission. Peripheral myelin protein (PMP22) is a key transmembrane protein involved in neuron myelination, the dysfunction of which can lead to significant human neuropathies. This report provides direct evidence that disease-associated PMP22 mutants are unstable and can self-associate to form dimers to a greater extent than wild-type protein, providing mechanistic insight into diseases such as Charcot-Marie-Tooth and Dejerine–Sottas syndrome. To accomplish this, we link mass-selected gas-phase protein stability measurements to in vivo protein trafficking data, paving the way for the future use of such data in understanding such complex biochemical processes.
A unique mode of keratinocyte death requires intracellular acidification
Authors: Matsui Takeshi , Kadono-Maekubo Nanako , Suzuki Yoshiro , Furuichi Yuki , Shiraga Keiichiro , Sasaki Hiroyuki , Ishida Azusa , Takahashi Sonoko , Okada Takaharu , Toyooka Kiminori , Sharif Jafar , Abe Takaya , Kiyonari Hiroshi , Tominaga Makoto , Miyawaki Atsushi , Amagai Masayuki
Published: April 2021

Significance

In specific tissues, cell death does not represent the end of cell function. The death of the uppermost stratum granulosum keratinocytes (SG1 cells) facilitates their conversion into stratum corneum (SC) corneocytes. Such cells are not removed by efferocytosis as would occur after apoptosis or necrosis; instead, nonviable cell bodies contribute to the protective barrier function of the SC. The present study demonstrates that SG1 cell death is initiated via a single episode of prolonged intracellular Ca
2+
elevation, followed by rapid acidification. Such intracellular ionic changes facilitate organellar degradation events specific to SC corneocyte formation. These findings further expand the current knowledge on cell death modes and highlight that nonviable cells contribute to physiological functions in specific contexts.
Nanobody cocktails potently neutralize SARS-CoV-2 D614G N501Y variant and protect mice
Authors: Pymm Phillip , Adair Amy , Chan Li-Jin , Cooney James P. , Mordant Francesca L. , Allison Cody C. , Lopez Ester , Haycroft Ebene R. , O’Neill Matthew T. , Tan Li Lynn , Dietrich Melanie H. , Drew Damien , Doerflinger Marcel , Dengler Michael A. , Scott Nichollas E. , Wheatley Adam K. , Gherardin Nicholas A. , Venugopal Hariprasad , Cromer Deborah , Davenport Miles P. , Pickering Raelene , Godfrey Dale I. , Purcell Damian F. J. , Kent Stephen J. , Chung Amy W. , Subbarao Kanta , Pellegrini Marc , Glukhova Alisa , Tham Wai-Hong
Published: April 2021

Significance

Neutralizing antibodies are important for immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and as therapeutics for the prevention and treatment of COVID-19. We identified high-affinity nanobodies against SARS-CoV-2 receptor-binding domain and found that nanobody cocktails consisting of two noncompeting nanobodies were able to block ACE2 engagement with RBD variants present in human populations and potently neutralize both wild-type SARS-CoV-2 and the N501Y D614G variant at low concentrations. Prophylactic administration of nanobody cocktails reduced viral loads in mice infected with the N501Y D614G SARS-CoV-2 virus, showing that nanobody cocktails are useful as prophylactic agents against SARS-CoV-2.
Knowledge about grammar and the role of epistemological beliefs
Authors: Elsner Daniela
Published: April 2021

This overview paper discusses two major dimensions of professional teacher competencies: content knowledge and beliefs about linguistics (or grammar, respectively). Research has found that teacher trainees as well as practicing teachers often have gaps in their knowledge about grammar. Since a lack of content knowledge has negative implications for teachers’ actions in the classroom, we need to think of ways to make teacher education in the field of linguistics more successful and sustainable. In the article, several approaches targeting the explanation of low grammatical content knowledge are assessed; however, an emphasis is put on the idea that epistemological beliefs play a major role for students’ learning success suggesting that there is a relationship between content knowledge and beliefs which should be further explored in future research.
Cordia obliqua (clammy cherry).
Authors: Rojas-Sandoval Julissa , Acevedo-Rodríguez Pedro
Published: April 2021

A datasheet on Cordia obliqua covering, as an economically important tree, its taxonomy, importance, silviculture, distribution, biology and ecology, uses, products and pests.
Roystonea oleracea (Caribbean royal palm).
Authors: Florin Madeleine
Published: April 2021

A datasheet on Roystonea oleracea covering, as an economically important tree, its taxonomy, importance, silviculture, distribution, biology and ecology, uses, products and pests.
Checklist for rapid assessment of independence in children with pediatric rheumatic diseases in transition to adult medical care
Authors: Miyamae Takako , Inoue Yuzaburo , Yamaguchi Kenichi
Published: April 2021

Objectives

The Committee for Support of Transition to Adult Medical Care, Pediatric Rheumatology Association of Japan, has developed a checklist for patients with pediatric rheumatologic diseases to evaluate readiness for transition to adult medical care.

Methods

Using checklists for general pediatric chronic diseases developed by researchers at the Ministry of Health, Labour and Welfare, committee members discussed points for modification or addition specific to pediatric rheumatic diseases and pediatric rheumatism clinical practice.

Results

Three patient-assessment checklists based on patient age and understanding level and a parent-assessment checklist were developed. The checklist for junior high school students and above included a ‘Health Education in Adolescence and Young Adulthood’ section with items related to sexual knowledge and concerns. Also, items on oral medications and subcutaneous injections management in the ‘Self-management of Daily Medical Care,’ domain and next medical visits management were added. The checklist for junior high school students included 30 items in seven domains and can be completed within 10 minutes. The checklist was given to 28 children with pediatric rheumatic diseases aged 10 years and older and their mothers.

Conclusion

The checklist was developed to share the challenges of independence during transition with patients and parents.