bluuebunny/crossref_metadata_2025 huggingface dataset:
The Development of High-Power LIBs Separators
Authors: Cui Chenyang , Li Qizhou , Zhuo Yongqi
Published: September 2021

Separators present the crucial functions of separating the positive and negative electrodes due to the free flow of lithium ions through the liquid electrolyte that fills in their open pore. Separators for liquid electrolyte Lithium-ion batteries can be classified into porous polymeric membranes, nonwoven mats, and cellulose separators. When a lithium-ion battery is being overcharged, it releases the heat and results in the inner-short. The polyethylene (PE) separators used here had shut down at around 135°C to cool the exothermal batteries. To enhance the meltdown temperature of the separator, a PE separator was coated with polymers synthesized from various ethylene glycol dimethacrylate monomers. At the same time, nonwoven mats have the potential to be low cost and thermally stable separators. Furthermore, the lithium-ion phosphate/lithium half cell using cellulose separator exhibited stable charge-discharge capability even at 120 °C. This paper presents an overview of the PE and PP membranes of lithium-ion battery separators, discusses how to solve their disadvantages, and reviews the cellulose-based materials developed for potential application in the lithium-ion battery.
Analysis of Global Policy and Impact on Automobile Industry under Carbon Neutrality
Authors: Huang Qirong
Published: September 2021

“Carbon Neutrality” means that enterprises, groups, or individuals calculate the total amount of greenhouse gas emissions produced directly or indirectly within a certain period and offset their Carbon dioxide emissions through afforestation, energy conservation, and emission reduction to achieve zero carbon dioxide emissions. Since 2020, the commitment to Carbon Neutrality has been paid attention to by various industries. Particularly, in the car industry, “Carbon Neutrality” has almost become one of the hottest directions. This paper focuses on policymaking and its impact on the automotive industry in the context of carbon neutrality. It is concluded that Carbon Neutrality is a problem that automobile enterprises must face. Automobile enterprises should set targets and time nodes related to Carbon Neutrality as soon as possible and speed up implementing specific measures. In addition, electric and new energy vehicles are more conducive to carbon emissions and carbon neutral transportation. Its development should also be put on the agenda.
The Influence of Pulp and Paper Industry on Environment
Authors: Jiang Shiyue , Li Binjie , Shen Yufei
Published: September 2021

Currently, paper consumption is globally increasing and at an unsustainable level. However, traditional paper production could release excessive greenhouse gas emissions or wastewater, resulting in environmental contamination. To make the result more visual and persuasive, this study takes Time magazine as an example to analyze the impacts of the papermaking process on the environment. This study analyzes energy consumption from several sectors in the paper industry, carbon dioxide emissions, and discharge of condensed wastewater to show current consumption during traditional pulp and paper production. Results show that the papermaking process would consume a lot of electricity during the pulp preparing, pulp condition, pulp preparation, manufacture paper with pulp, and pulp processing stages. Meanwhile, various degree of carbon emissions is generated based on the physical and chemical changes in materials during the papermaking process. Two kinds of wastewater, including black and white liquor, are produced in the papermaking process. Several countermeasures are suggested to achieve a low consumption and sustainable development of the pulp and paper industry to solve these environmental problems. The suggestion includes the surrogate of electronic paper, carbon capture and storage, and wastewater recycling.
A Study on modification of polylactic acid and its biomedical application
Authors: Huang Yi , Wang Yu , Wen Jiarui
Published: September 2021

Polylactic acid (PLA) is one of the most extensively studied biodegradable materials. PLA is a versatile material with excellent bio-compatibility, bioabsorbability, biodegradability, and low toxicity. As an environmentally friendly polymer, PLA is favored by researchers and has explored many commercial applications, playing an important role in medicine and industry to replace many traditional petrochemical-based polymers. However, the strength and mechanical properties of PLA need to be improved to meet the practical application of multiple scenarios. The purpose of this review is to explore the modification methods of grafted copolymerization and block co-polymerization to improve the performance of PLA. This review also focuses on the medical applications and covers some non-medical applications of PLA.
Biostatistical investigation of correlation between breastfeeding and obesity
Authors: Chen Yixin
Published: September 2021

Breastfeeding is a classic aspect of health, which has benefits for both children and mothers in the long and short terms. In Europe, the obesity epidemic for children becomes an urgent problem needed to be solved. Recent research indicates that prolonging breastfeeding time would reduce the proportion of obesity and overweight. Breastfeeding has been seen as a protective factor. In this article, we make a secondary analysis of the data from several European countries in the WHO European Childhood Obesity Surveillance Initiative (COSI) to study the correlation between breastfeeding and obesity. This survey is the fourth round. The result shows that there is a positive correlation between breastfeeding and obesity.
Inheritance and Update of Chinese Traditional Windows in Landscape Architecture
Authors: Wang Haojun
Published: September 2021

Chinese Architecture has a long history, which makes Chinese buildings more than shelters. Chinese traditional windows are just like buildings, having more meaningful contents. They have very high cultural and artistic significance. However, nowadays, when the word “window” is mentioned, most people regard it as a structure used for letting in the natural light. Chinese traditional windows are gradually replaced by modern windows, especially after the 1980s, for traditional windows are somehow not satisfied with the demands of modern life. After the reform and opening, China has learned the technology of modern windows made of aluminum alloy from Europe, the United States, Japan, and other developed countries. As a result, the cultural connation of Chinese traditional windows art in landscape architecture is disappearing. To inherit traditional Chinese windows in landscape architecture, Chinese architects need to update traditional Chinese windows by using modern materials, techniques, and methods. The first part of this article discusses the main physical elements of traditional Chinese windows of landscape architecture. The second part of this article discusses the cultural connotation of Chinese traditional windows art of landscape architecture. The last part of this article discusses how to use new materials and technology to retain and update some parts of traditional windows that are of great significance in Chinese traditional windows art of landscape architecture. And there are three main approaches. Firstly, use WPC to replace traditional wood, which has better properties and keeps the feelings and cultural connation brought by wood. Secondly, use fewer materials and simple shapes to simplify traditional windows bars to make them suitable for modern life. Thirdly, rethink the design of windows and design the windows and the landscape as a whole. In the future, the new Chinese windows of landscape architecture will be popular all over the country again.
An Analysis of the Effect of selected Factors on microsurgical Performance
Authors: Zyluk Andrzej , Czernikiewicz Konrad , Antoniak Joanna , Abramczyk Urszula
Published: September 2021

Background Microsurgery is a specific surgical expertise that involves operating on very small structures, and requires the assistance of a magnifying device: a microscope or loupes. Several factors have been identified that could affect the quality of microsurgical performance in training or surgical procedures.

Objective The objective of this study was to assess the impact of the selected factors – caffeine, alcohol and physical exercise – on a microsurgical task prior its performance.

Methods Ten students from the 5th and 6th years of medical studies who had completed the advanced microsurgical course performed a “6-stitches test” on a latex glove spanned over a cup prior to and after consumption of caffeine, alcohol and performing physical exercises. The times taken to complete the task at baseline and post-exposure were recorded.

Results The results of the study show a statistically significant positive effect of caffeine and a statistically significant negative effect of physical exercise on microsurgical performance when performed shortly before the task. Small dose of alcohol taken before the task showed had little effect on performance.
Zahnärztlich-chirurgische Vorbereitung und Unterstützung kieferorthopädischer Maßnahmen
Authors: Seeberger Robin , Weickum Rolf
Published: September 2021

Das Ziel chirurgischer Maßnahmen während oder vor einer kieferorthopädischen Therapie ist die Erleichterung der Einstellung und der langfristige Erhalt einer stabilen Okklusion sowie die Ausformung der Zahnbögen, wenn dies mit kieferorthopädischen Mitteln allein nicht realisierbar ist.

Die in diesem Artikel beschriebenen Eingriffe können unter der Voraussetzung entsprechender Kompetenz des Behandlers und der erforderlichen technischen Ausstattung auch in der hauszahnärztlichen Praxis durchgeführt werden.
Zähneputzen und akute respiratorische Infektionen in
Kindertageseinrichtungen (ZINFEKT): Eine ökologische Studie in
ausgewählten Regionen Niedersachsens (2013–2018)
Authors: Karow Anja , Bruns-Philipps Elke , Holle Ina , Jahn Nicola , von Lengerke Thomas
Published: September 2021

Ziel der Studie Die zahnmedizinische Gruppenprophylaxe in
Kindertageseinrichtungen (Kitas) und das in dieser Studie als einer ihrer
Bausteine untersuchte Zähneputzen sollen Kariesinzidenz reduzieren und
Zahngesundheit fördern. Bei der Umsetzung dieser Maßnahme treten
allerdings verschiedene Barrieren auf. So wird ein erhöhtes
Übertragungsrisiko respiratorischer Infektionskrankheiten in den Kitas
befürchtet. In der ZINFEKT-Studie sollte überprüft
werden, ob und in welchem Ausmaß Unterschiede in der Häufigkeit
akuter respiratorischer Erkrankungen (ARE) zwischen Kitas auftreten, die
Zähneputzen implementieren, und Kitas, die die Maßnahme nicht
umsetzen.

Methodik In einer ökologischen Studie wurden für
N=33 Kitas aus der kreisfreien Stadt Braunschweig, der Region Hannover
und dem Landkreis Osnabrück Daten der ARE-Surveillance des
Niedersächsischen Landesgesundheitsamts 2013–2018 mit Angaben
des Zahnärztlichen Dienstes zum Zähneputzen verknüpft.
Als Beobachtungseinheiten wurden (in Anlehnung an das Konzept der
„Patiententage“ der Infektions-Surveillance im Krankenhaus)
„kranke Kinderwochen“ als Wochen definiert, in denen für
ein in der Kita angemeldetes Kind eine ARE berichtet wurde. Neben Kreuztabellen
wurden relative Risiken für kranke Kinderwochen in Abhängigkeit
vom Zähneputzen sowie Breslow-Day-Tests für Interaktionen mit
Ort, Kita-Größe, ARE-Saison und Zeitfenster innerhalb von
ARE-Saisons durchgeführt.

Ergebnisse Insgesamt war der Anteil an kranken Kinderwochen in den Kitas,
die Zähne putzten, um 4,6% höher als in Kitas ohne
Zähneputzen (17,9 vs. 13,3%; p<0,0001). Die Richtung
dieses Unterschiedes änderte sich in den nach den räumlichen und
zeitlichen Ko-Variablen stratifizierten Analysen mit einer Ausnahme (Kitas mit
50 oder weniger angemeldeten Kindern) nicht.

Schlussfolgerung Die Annahme, dass regelmäßiges
Zähneputzen in Kitas mit höheren ARE-Raten einhergeht, scheint
angesichts der Ergebnisse eine empirische Entsprechung zu haben. Allerdings
spricht der gefundene Unterschied trotz der Limitationen der Studie (vor allem
das ökologische Studiendesign und mögliche
Einschränkungen der Repräsentativität der Kitas) sowohl
angesichts seiner Größe als auch der möglicherweise noch
optimierbaren Hygiene-Compliance unseres Erachtens nicht gegen das
Zähneputzen als Teil der zahnmedizinischen Gruppenprophylaxe in
Kitas.
COVID-19 zwischen Disruption und Transformation der
öffentlichen Gesundheit: Erste Lehren aus Perspektive des
Nachwuchses
Authors: Sell Kerstin , Kuhn Eva , Arnold Laura , Boehm Claudia , Gepp Sophie , Havemann Matthias , Herrmann Lukas , Hommes Franziska , Jung Laura , Mathé Philipp , Mörschel Katharina , Stratil Jan , Fischer Florian
Published: September 2021

Die COVID-19-Pandemie hat vielfältige Herausforderungen für
Public Health und den Öffentlichen Gesundheitsdienst (ÖGD) in
Deutschland offenbart bzw. verstärkt. Sie bietet jedoch auch ein
Gelegenheitsfenster für eine langfristig wirksame Transformation im
Bereich der öffentlichen Gesundheit. Vor diesem Hintergrund erfolgte im
Oktober und November 2020 eine Online-Befragung der Mitglieder des
Nachwuchsnetzwerkes Öffentliche Gesundheit (NÖG), in welcher die
Erfahrungen mit und der Blick auf Public Health während der
COVID-19-Pandemie eruiert wurden und sich erste Erkenntnisse aus der Pandemie
für den deutschen Public-Health-Kontext abzeichneten. In diesem Beitrag
werden diese vorgestellt und ausgehend von den Ergebnissen der Befragung
Desiderate formuliert, welche zielgerichtete und konkrete Anhaltspunkte
für die Weiterentwicklung und Förderung der öffentlichen
Gesundheit geben sollen. Zentrale Themen, welche die befragten
Nachwuchsfachkräfte beschäftigten, waren die erhöhte
öffentliche und politische Aufmerksamkeit für
öffentliche Gesundheit mit einer Fokussierung auf den Infektionsschutz,
der Stellenwert von Public Health in Deutschland sowie Stärken und
Schwächen von Public-Health-Strukturen und -Fachkräften. Die
Desiderate zielen auf eine langfristige und holistische Stärkung von
Public Health ab, in der die Ausbildung interdisziplinärer
Nachwuchsfachkräfte einen hohen Stellenwert einnimmt.
Impact of Body Mass Index, Age and Tobacco Use on the Outcomes of Immediate Breast Reconstruction with Implants and Acellular Dermal Matrix
Authors: Ribeiro L. Mata , Meireles Rita P. , Brito Irís M. , Costa Patrícia M. , Rebelo Marco A. , Barbosa Rui F. , Choupina Miguel P. , Pinho Carlos J. , Ribeiro Matilde P.
Published: September 2021

Background This study aimed to analyze the effect of body mass index (BMI), age, and tobacco use on alloplastic breast reconstruction.

Methods We conducted a retrospective study of patients who submitted to immediate breast reconstructions with an anatomical implant and acellular dermal matrix in a single center between 2016 and 2018. Outcomes evaluated included immediate complications, early complications, reinterventions, readmissions, and reconstruction failure. Patients were divided into two groups concerning each potential risk factor (BMI < or ≥25; age < or ≥ 50 years; and smokers vs nonsmokers). Simple descriptive statistics and univariate analysis were performed.

Results A total of 101 breast reconstructions (73 patients) were included in the analysis. The mean BMI was 24, and the mean age was 44.5 years old. Smokers accounted for 14 breast reconstructions (13.9%). The rate of early infections, mastectomy flap necrosis, and implant removal was significantly higher in overweight patients. The total volume of breast drainage was higher in the age ≥ 50 years group. Smoking did not alter the outcomes.

Conclusions A BMI ≥ 25 is a risk factor for early infections and reconstructive failure. Age ≥ 50 years is associated with a higher volume of breast drainage but does not seem to impact the success of the reconstruction. Smoking does not appear to affect the outcomes significantly in this type of reconstruction. Surgeons should consider delaying the reconstruction or using autologous tissue when patients are overweight.
Repair of Fractures of the Lateral Aspect of the Humeral Condyle in Skeletally Mature Dogs with Locking and Non-Locking Plates
Authors: Eayrs Matthew K. , Guerin Vincent , Grierson James , Moores Andrew P.
Published: September 2021

Objective The aim of this study was to report the functional outcome and complications following transcondylar screw and epicondylar plate fixation of skeletally mature dogs with fractures of the lateral aspect of the humeral condyle using a string of pearls, limited contact dynamic compression plate (LC-DCP) or locking compression plate (LCP).

Study Design This study was a retrospective review of clinical records, radiographic images and canine brief pain inventory evaluation with a supplementary non-validated questionnaire.

Results Thirty-one fractures in 29 dogs were included. The majority of dogs were Spaniels (23/29). Thirty fractures had evidence of humeral intracondylar fissure. Sixteen fractures had string of pearls, eight LCP and seven LC-DCP. There were two minor complications and three major complications. Perioperative (median: 6 weeks, range: 6–12) outcome was considered fully functional for 24 fractures and acceptable for 6 fractures. One dog had an unacceptable outcome due to the failure of an LCP that healed following revision surgery. Fractures with radiographic follow-up had a persistent visible intracondylar fracture line in 20/26. Twenty-six of twenty-seven owners perceived an excellent outcome (median: 135 weeks, range: 25–246).

Conclusion Repair of fractures of the lateral aspect of the humeral condyle with a transcondylar screw and epicondylar plate has a good perioperative, mid- and long-term outcome with 10% major complication rate, despite incomplete or non-union of the intracondylar fracture in 20/26 elbows.
Improving robustness in interdependent networks under intentional attacks by optimizing intra-link allocation
Authors: Hao Yucheng , Jia Limin , Wang Yanhui , He Zhichao
Published: September 2021

The interdependent network is particularly vulnerable to attacks on high degree nodes; therefore, the improvement of its robustness under intentional attacks has become an important topic. In this paper, we put forward a new metric to quantify the robustness of interdependent networks against intentional attacks and develop an improved simulated annealing algorithm (ISAA) to maximize this metric by optimizing the allocation of intra-links in subnetworks. Based on the comparison between the ISAA and existing algorithms, it is found that the algorithm presented in this paper is more effective to enhance the robustness of an interdependent scale-free network (ISFN). By applying the ISAA to ISFNs with different coupling preferences, there is a key finding that the robustness of the optimized ISFN is significantly stronger than that of the original ISFN. In particular, for cases of disassortative and random couplings, no sudden collapse occurs in optimized ISFNs. According to the analysis of the degree and the clustering coefficient, we find that the subnetwork of the optimized ISFN exhibits an onion-like structure. In addition, the ISFN whose robustness is enhanced to resist the attacks on high degree nodes is still robust to the intentional attacks concerning the betweenness and PageRank.
Vacancy-induced enhancement of electron–phonon coupling in cubic silicon carbide and its relationship to the two-temperature model
Authors: Al Smairat Salah , Graham Joseph
Published: September 2021

The electron–phonon coupling factor was calculated for both pristine and vacancy-rich 3C-SiC. Ab initio calculations were performed within the framework of the density functional perturbation theory. Wannier functions were used to interpolate eigenvalues into denser grids through the electron–phonon using Wannier code. The coupling factor was determined through calculations of the electron self-energy, electron–phonon relaxation time, and electronic specific heat. These parameters were extrapolated to high temperatures using a hybrid model which mixes band calculations for electrons below an energy cutoff with the free electron gas model for electrons above the energy cutoff. The electron relaxation times, specific heats, electron drift mobilities, and electron–phonon coupling factors were calculated as a function of electron temperature. Si and C vacancies were found to have a profound effect on electron–phonon coupling for all temperatures, while electronic specific heat capacity was found to be most affected at cryogenic temperatures. The electron drift mobility was calculated at different temperatures using the scattering time. Calculated mobilities were validated with Hall mobility measurements reported in the literature. The importance of structural defects on the electron–phonon coupling is discussed in the context of the two-temperature model, a model that has been widely used to understand aspects of the interaction of solids with pulsed laser irradiation and swift heavy ion irradiation.
High thermoelectric power factors in polycrystalline germanium thin films
Authors: Ozawa T. , Imajo T. , Suemasu T. , Toko K.
Published: September 2021

The high potential of polycrystalline Ge as a thin-film thermoelectric material was demonstrated. We synthesize a polycrystalline Ge layer on an insulating substrate at 450 °C via advanced solid-phase crystallization and control its carrier concentration through the solid-phase diffusion of various p- and n-type dopants. The heating deposition (150 °C) of the amorphous precursor considerably improves the crystal quality of the polycrystalline Ge layer as well as the doping properties. The solid-phase diffusion of Ga and P dopants onto the Ge layers allows for control of the carrier concentration in the ranges of 1017–1020 cm−3 for p-type and 1018–1019 cm−3 for n-type, respectively, by modulating the diffusion annealing temperature and time. Because of the high electrical conductivities reflecting the carrier mobilities and carrier concentrations, the maximum power factors reach a value of 1080 μW m−1 K−2 for p-type and 2300 μW m−1 K−2 for n-type at room temperature. These power factors are higher than those of most polycrystalline semiconductor thin films formed at temperatures below 1000 °C. Therefore, this study serves as a milestone toward high-performance and reliable thin-film thermoelectric generators based on an environmentally friendly semiconductor.
Reversible modulation of metal–insulator transition in VO2 via chemically induced oxygen migration
Authors: Han Kun , Wang Hanyu , Wu Liang , Cao Yu , Qi Dong-Chen , Li Changjian , Huang Zhen , Li Xiao , Renshaw Wang X.
Published: September 2021

Metal-insulator transition (MIT), an intriguing correlated phenomenon induced by the subtle competition of the electrons' repulsive Coulomb interaction and kinetic energy, is of great potential use for electronic applications due to the dramatic change in resistivity. Here, we demonstrate a reversible control of MIT in VO2 films via oxygen stoichiometry engineering. By facilely depositing and dissolving a water-soluble yet oxygen-active Sr3Al2O6 capping layer atop VO2 at room temperature, oxygen ions can reversibly migrate between VO2 and Sr3Al2O6, resulting in a gradual suppression and a complete recovery of MIT in VO2. The migration of the oxygen ions is evidenced in a combination of transport measurement, structural characterization, and first-principles calculations. This approach of chemically induced oxygen migration using a water-dissolvable adjacent layer could be useful for advanced electronic and iontronic devices and studying oxygen stoichiometry effects on the MIT.
Multiscale molecular kinetics by coupling Markov state models and reaction-diffusion dynamics
Authors: del Razo Mauricio J. , Dibak Manuel , Schütte Christof , Noé Frank
Published: September 2021

A novel approach to simulate simple protein–ligand systems at large time and length scales is to couple Markov state models (MSMs) of molecular kinetics with particle-based reaction-diffusion (RD) simulations, MSM/RD. Currently, MSM/RD lacks a mathematical framework to derive coupling schemes, is limited to isotropic ligands in a single conformational state, and lacks multiparticle extensions. In this work, we address these needs by developing a general MSM/RD framework by coarse-graining molecular dynamics into hybrid switching diffusion processes. Given enough data to parameterize the model, it is capable of modeling protein–protein interactions over large time and length scales, and it can be extended to handle multiple molecules. We derive the MSM/RD framework, and we implement and verify it for two protein–protein benchmark systems and one multiparticle implementation to model the formation of pentameric ring molecules. To enable reproducibility, we have published our code in the MSM/RD software package.
Bejan's flow visualization of buoyancy-driven flow of a hydromagnetic Casson fluid from an isothermal wavy surface
Authors: Kumar Mahesh , Mondal Pranab Kumar
Published: September 2021

The proposed work numerically investigates the buoyancy-driven flow of Casson fluid from a vertical wavy surface under the influence of a magnetic field and evaluates the underlying transport of heat in the free convective regime both quantitatively and qualitatively. Pertaining to this analysis, the primitive forms of coupled non-linear partial differential equations are evaluated with the help of an efficient and straightforward Crank–Nicolson implicit finite difference technique. By representing the graphical plots of flow velocity, temperature, and friction-factor coefficients, obtained for different physical parametric values pertinent to this analysis, we discuss the influence of the Hartmann number, surface waviness parameter, and rheological parameter of the fluid on the underlying thermohydrodynamics. In addition to the isotherm and streamline plots, by demonstrating the functional form, we discuss an extensive flow visualization technique that provides unique heat flow visualization for the wavy surface based on Bejan's heat function concept. The results indicate that for increasing the magnitude of the magnetic parameter, the evolution of isotherms, streamlines, and heatlines deviates periodically with a higher amplitude, which signifies the transfer of high heat energy as well as the efficient transport of heat in the convective regime.
Asymmetrical dynamics of epidemic propagation and awareness diffusion in multiplex networks
Authors: Sun Mengfeng , Tao Yizhou , Fu Xinchu
Published: September 2021

To better explore asymmetrical interaction between epidemic spreading and awareness diffusion in multiplex networks, we distinguish susceptibility and infectivity between aware and unaware individuals, relax the degree of immunization, and take into account three types of generation mechanisms of individual awareness. We use the probability trees to depict the transitions between distinct states for nodes and then write the evolution equation of each state by means of the microscopic Markovian chain approach (MMCA). Based on the MMCA, we theoretically analyze the possible steady states and calculate the critical threshold of epidemics, related to the structure of epidemic networks, the awareness diffusion, and their coupling configuration. The achieved analytical results of the mean-field approach are consistent with those of the numerical Monte Carlo simulations. Through the theoretical analysis and numerical simulations, we find that global awareness can reduce the final scale of infection when the regulatory factor of the global awareness ratio is less than the average degree of the epidemic network but it cannot alter the onset of epidemics. Furthermore, the introduction of self-awareness originating from infected individuals not only reduces the epidemic prevalence but also raises the epidemic threshold, which tells us that it is crucial to enhance the early warning of symptomatic individuals during pandemic outbreaks. These results give us a more comprehensive and deep understanding of the complicated interaction between epidemic transmission and awareness diffusion and also provide some practical and effective recommendations for the prevention and control of epidemics.
High photoresponsivity of multilayer MoSe2 phototransistors decorated with Au nanoseeds
Authors: Hong Seongin , Baek Seungho , Kim Sunkook
Published: September 2021

In this paper, we report the fabrication and photoresponsive characteristics of MoSe2 phototransistors decorated with Au nanoseeds. The Au nanoseeds were excellently deposited onto the MoSe2 phototransistors by electron-beam evaporation with an extremely low deposition rate. This simple but effective method improved the photoresponsivity of the MoSe2 phototransistor by 276% compared to that of a pristine MoSe2 phototransistor, owing to the surface plasmon resonance effect of the Au nanoseeds. The results reveal that this method can provide a promising route for achieving high-performance photosensors.
Bias-driven conductance switching in encapsulated graphene nanogaps
Authors: Pyurbeeva Eugenia , Swett Jacob L. , Ye Qingyu , Kennedy Oscar W. , Mol Jan A.
Published: September 2021

Feedback-controlled electric breakdown of graphene in air or vacuum is a well-established way of fabricating tunnel junctions, nanogaps, and quantum dots. We show that the method is equally applicable to encapsulated graphene constrictions fabricated using hydrogen silsesquioxane. The silica-like layer left by hydrogen silsesquioxane resist after electron-beam exposure remains intact after electric breakdown of the graphene. We explore the conductance switching behavior that is common in graphene nanostructures fabricated via feedback-controlled breakdown and show that it can be attributed to atomic-scale fluctuations of graphene below the encapsulating layer. Our findings open up routes for fabricating encapsulated room-temperature single-electron nanodevices and shed light on the underlying physical mechanism of conductance switching in these graphene nanodevices.
Mirror symmetric nonreciprocity and circular transmission in cavity magnonics
Authors: Shi Yongzhang , Zhang Chi , Jiang Changjun , Ong C. K. , Chai Guozhi
Published: September 2021

We investigated the magnon–photon coupling in a threefold symmetry open cavity magnonic system, which leads to the mirror symmetric nonreciprocity and circular transmission. The strengths of the transmission coefficient in the anti-crossing area of the photon–magnon couplings are fully asymmetric. The results reveal the chiral selected circular transmission characteristic and the mirror symmetric nonreciprocity of the microwave transmission in the designed system. These effects can be understood with the chiral phase difference in the magnon–photon coupling, which lead to the circular microwave transmission. This scheme might be used as a circulator type non-reciprocal device in the cavity quantum electrodynamic systems.
Precise prediction of the drag reduction efficiency of polymer in turbulent flow considering diameter effect
Authors: Zhang Xin , Dai Xiaodong , Zhao Jishi , Jing Dengwei , Liu Fei , Li Lei , Xin Yanping , Liu Kun
Published: September 2021

One important issue for drag reduction of turbulent flow with polymers is the pipe diameter effect. Although this scale-up effect has been extensively investigated, there are still debates. For instance, when using the traditional scaling law to predict the friction factor in pipe flow of wide pipe diameters, the relative errors between experimental data and predicted values can be up to 1000%. This paper develops a new method to predict the friction factor in pipe flow applicable to a wide range of pipe diameters. The new method developed in this study transforms the Reynolds number (Re) vs friction factor (f) to log10(Ref) vs 1/f in the Prandtl–von Karman coordinate, where the latter two parameters are correlated on straight lines. We find that the slope and intercept of these straight lines can be predicted by empirical correlations involving diameters and polymer concentrations. Thus, if Re and f from a pipe flow of small diameter are known, these two correlations for slope and intercept can predict the cases for large pipe diameters. With our method, most relative errors between the predicted values and experimental data are within 20%, much better than the traditional scaling law. Finally, we point out the physical meaning of the slope and intercept, and make it clear why the previous scaling law becomes not reliable when it is employed to predict the friction factor for pipe flow with a too wide range of pipe diameters.
Fabrication and surface treatment of electron-beam evaporated niobium for low-loss coplanar waveguide resonators
Authors: Kowsari D. , Zheng K. , Monroe J. T. , Thobaben N. J. , Du X. , Harrington P. M. , Henriksen E. A. , Wisbey D. S. , Murch K. W.
Published: September 2021

We characterize low-loss electron-beam evaporated niobium thin films deposited under ultra-high vacuum conditions. Slow deposition yields films with a high superconducting transition temperature (9.20±0.06 K) as well as a residual resistivity ratio of 4.8. We fabricate the films into coplanar waveguide resonators to extract the intrinsic loss due to the presence of two-level-system fluctuators using microwave measurements. For a coplanar waveguide resonator gap of 2 μm, the films exhibit filling-factor-adjusted two-level-system loss tangents as low as 1.5×10−7 with single-photon regime internal quality factors in excess of one million after removing native surface oxides of the niobium.
From Apollo to Artemis: A Laser's Journey Through Space
Authors: Gaza Ramona
Published: September 2021

Space exploration is in an extremely exciting and challenging phase. No longer the sole domain of governments, today governments are actively look toward private business as active partners. Hand in hand with this expansion of space exploration comes an increased application of laser technology. Therefore, it is critical that all parties understand the potential risk presented by laser use in space. This includes the use of lasers as aids in docking, lidar, and communications. Even in this unique environment, concerns and the potential for exposure to both those in space and on Earth exist. This chapter reviews those concerns and standards that have been generated, and some controls unique to this environment.
Laser Safety in Educational Institutions
Authors: Seeber Fred P.
Published: September 2021

When the phrase “laser use in education” is mentioned, many think of the academic university level, graduate students, and physics labs. But with the emphasis on STEM (science, technology, engineering, and mathematics) studies, the introduction of laser technology in the public-school grades is more common and important than one may consider. This presents a number of laser safety concerns, including the safety of students and the lack of laser safety background for the majority of the instructors. In addition, there is the unique consideration of maturity—an item not found in almost any laser safety guidance standard. Following and understanding instructions differ across the different grade levels. This chapter provides direction and guidance for different grade levels, as well as considers laser safety challenges at the optics higher education level.
Laser Safety at a Trade Show/Exhibition
Authors: Ciprazo Eddie O. , Barat Ken
Published: September 2021

The trade show, which demonstrates laser devices or products, whether oriented toward research, medical, industrial, high tech or military applications, presents a setting where a laser injury can occur as conference attendees mill around unrestricted spaces. This unique setting is one in which laser safety deficiencies need to be addressed in an immediate fashion. Exhibits or trade shows, sponsoring organizations, or venue management need to ensure no one visiting the show will be inadvertently injured by laser radiation. The primary step is to have a laser safety specialist audit all show displays that contain lasers. The authority of this person needs to be clear and understood by all parties. Any contracts between the venue management and exhibitor should include a statement clearing addressing laser safety and the authority of the show's laser safety officer. An injury will most likely occur to an unsuspecting member of the public, or someone trying to get a better view or understanding of the display product. It is the responsibility of the booth occupants and venue to take steps to prevent such an incident. This chapter reviews the elements that go into such trade shows from set up to when the public is present.
A revised action spectrum for vitamin D synthesis by suberythemal UV radiation exposure in humans in vivo
Authors: Young Antony R. , Morgan Kylie A. , Harrison Graham I. , Lawrence Karl P. , Petersen Bibi , Wulf Hans Christian , Philipsen Peter A.
Published: September 2021

Significance

Solar UV radiation (UVR) causes sunburn but initiates the first step of vitamin D synthesis, which is the formation of previtamin D3(pre-D3) in skin. The gold standard for assessing vitamin D is serum 25-hydroxyvitamin D3[25(OH)D3]. Public health advice for optimal solar exposure requires UVR wavelength-dependence (action spectrum) data on risks and benefits. An action spectrum for pre-D3in human ex vivo skin was established over 30 y ago, but its validity has been questioned. We tested this action spectrum in healthy volunteers using serum 25(OH)D3as the endpoint. Our analysis shows that the pre-D3action spectrum can be improved with a systematic correction. This will result in better risk–benefit calculations for public health advice on solar exposure.
Tropical islands of the Anthropocene: Deep histories of anthropogenic terrestrial–marine entanglement in the Pacific and Caribbean
Authors: Fitzpatrick Scott M. , Giovas Christina M.
Published: September 2021

Islands are useful model systems for examining human–environmental interactions. While many anthropogenic effects visible in the archaeological and paleoecological records are terrestrial in nature (e.g., clearance of tropical forests for agriculture and settlement; introduction of nonnative flora and fauna), native peoples also relied heavily on marine environments for their subsistence and livelihood. Here we use two island case studies—Palau (Micronesia) and the Lesser Antilles (Caribbean)—and approach their long-term settlement history through a “ridge-to-reef” perspective to assess the role that human activity played in land- and seascape change over deep time. In particular, we examine the entanglement of terrestrial and marine ecosystems resulting from anthropogenic effects and cultural responses to socio-environmental feedback. We suggest that on the humanized tropical islands of the Anthropocene, mangroves, near shore and littoral areas, and coral reefs were major sites of terrestrial–marine interface chronicling and modulating anthropogenic effects.
Historical socioecological transformations in the global tropics as an Anthropocene analogue
Authors: Penny Dan , Beach Timothy P.
Published: September 2021

Large, low-density settlements of the tropical world disintegrated during the first and second millennia of the CE. This phenomenon, which occurred in South Asia, Southeast Asia, and Mesoamerica, is strongly associated with climate variability and extensive landscape transformation. These profound social transformations in the tropical world have been popularized as “collapse,” yet archaeological evidence suggests a more complex and nuanced story characterized by persistence, adaptation, and resilience at the local and regional scales. The resulting tension between ideas of climate-driven collapse and evidence for diverse social responses challenges our understanding of long-term resilience and vulnerability to environmental change in the global tropics. Here, we compare the archetypal urban collapse of the Maya, in modern Belize, Guatemala, Honduras, and Mexico, during the 8th to 11th centuries CE, and the Khmer in modern Cambodia, Laos, Thailand, and Vietnam during the 14th to 15th centuries CE. We argue that the social response to environmental stress is spatially and temporally heterogenous, reflecting the generation of large-scale landesque capital surrounding the urban cores. Divergences between vulnerable urban elite and apparently resilient dispersed agricultural settlements sit uncomfortably with simplistic notions of social collapse and raise important questions for humanity as we move deeper into the Anthropocene.
Anthropogenic transitions from forested to human-dominated landscapes in southern Macaronesia
Authors: Castilla-Beltrán Alvaro , de Nascimento Lea , Fernández-Palacios José-María , Whittaker Robert J. , Willis Kathy J. , Edwards Mary , Nogué Sandra
Published: September 2021

Significance

Assessing the ecological consequences of human settlement can help preserve island forests and their ecosystem services, but to understand the legacy of these interactions requires datasets that span centuries. We used paleoecological data (e.g. fossil pollen) to show that prehuman Holocene forests were dynamic in response to climatic changes, and that human colonization led to increased incidence of fire, soil erosion, and grazing impacts in the Canary Islands and Cabo Verde. Humans have driven compositional convergence within the thermophilous woodland zone of Cabo Verde but in the Canary Islands relictual fragments of laurel forests persist. Our long-term view highlights the legacy of past human impacts and which tree species to restore and conserve in thermophilous woodlands within these biodiversity hotspots.
Human impacts and Anthropocene environmental change at Lake Kutubu, a Ramsar wetland in Papua New Guinea
Authors: Long Kelsie E. , Schneider Larissa , Connor Simon E. , Shulmeister Niamh , Finn Janet , Roberts Georgia L. , Zawadzki Atun , Enge T. Gabriel , Smol John P. , Ballard Chris , Haberle Simon G.
Published: September 2021

Significance

Wetland environments are increasingly threatened by climate change, population expansion, resource extraction, forest clearance, and pollution. The Ramsar Convention aims to monitor internationally important wetlands to ensure their ongoing maintenance and survival through wise use and management. However, many wetlands have undergone substantial human-induced changes prior to being listed with Ramsar. In the case of Lake Kutubu, a Ramsar wetland situated in the tropical rainforests of Papua New Guinea, paleoecological indicators preserved in lake sediments have been used to identify baseline conditions and to track anthropogenic impacts over time. This methodology can be applied to wetlands around the world to determine baseline environmental conditions and to track historic ecological changes in areas where constant monitoring has not been possible.
Indigenous knowledge and the shackles of wilderness
Authors: Fletcher Michael-Shawn , Hamilton Rebecca , Dressler Wolfram , Palmer Lisa
Published: September 2021

The environmental crises currently gripping the Earth have been codified in a new proposed geological epoch: the Anthropocene. This epoch, according to the Anthropocene Working Group, began in the mid-20th century and reflects the “great acceleration” that began with industrialization in Europe [J. Zalasiewicz et al.,
Anthropocene
19, 55–60 (2017)]. Ironically, European ideals of protecting a pristine “wilderness,” free from the damaging role of humans, is still often heralded as the antidote to this human-induced crisis [J. E. M. Watson et al.,
Nature
, 563, 27–30 (2018)]. Despite decades of critical engagement by Indigenous and non-Indigenous observers, large international nongovernmental organizations, philanthropists, global institutions, and nation-states continue to uphold the notion of pristine landscapes as wilderness in conservation ideals and practices. In doing so, dominant global conservation policy and public perceptions still fail to recognize that Indigenous and local peoples have long valued, used, and shaped “high-value” biodiverse landscapes. Moreover, the exclusion of people from many of these places under the guise of wilderness protection has degraded their ecological condition and is hastening the demise of a number of highly valued systems. Rather than denying Indigenous and local peoples’ agency, access rights, and knowledge in conserving their territories, we draw upon a series of case studies to argue that wilderness is an inappropriate and dehumanizing construct, and that Indigenous and community conservation areas must be legally recognized and supported to enable socially just, empowering, and sustainable conservation across scale.
Photoprotection during iron deficiency is mediated by the bHLH transcription factors PYE and ILR3
Authors: Akmakjian Garo Z. , Riaz Nabila , Guerinot Mary Lou
Published: September 2021

Significance

Iron deficiency has many adverse effects on photosynthesis, which is not surprising given that 90% of foliar iron is found in the chloroplast. Although many iron-sparing mechanisms have been documented, a mechanistic understanding of how chloroplasts adapt to iron deficiency was lacking. Here, we show that the bHLH transcription factors ILR3 and PYE are required for photoprotection during iron deficiency. Changes in chloroplast morphology under the control of these transcription factors prevents the production of harmful reactive oxygen species and allows for repair of photosystem II. Understanding how plants adapt the photosynthetic machinery during iron deficiency may allow us to optimize plant growth in soils where iron is not bioavailable.
Cosmopolitan morality trades off in-group for the world, separating benefits and protection
Authors: Bai Xuechunzi , Gauri Varun , Fiske Susan T.
Published: September 2021

Significance

Contemporary world challenges—pandemic response, climate change, migration, global poverty, and trade policy—require comparative moral judgments (tradeoffs) between one’s own and other nations. Such choices distribute benefits and protect security for just the national in-group or the whole world. In representative surveys from eight countries, most respondents are willing to sacrifice national well-being to aid foreigners, more to protect from harms than to redistribute benefits. This disaggregates two dimensions of moral cosmopolitanism (benefiting versus protecting), distinguishes it from adjacent constructs (such as group identity), and demonstrates links to attitudes and behaviors. Cognitive associations (global, inclusive words) reflect cosmopolitan thinking; making the world salient can elicit cosmopolitan behavior, at least temporarily. Understanding this global perspective can guide its enhancement.
Physical processes controlling the rifting of Larsen C Ice Shelf, Antarctica, prior to the calving of iceberg A68
Authors: Larour E. , Rignot E. , Poinelli M. , Scheuchl B.
Published: September 2021

Significance

The stability of Antarctica and its contribution to sea-level rise are determined by the evolution of its ice shelves, which are vast expanses of floating ice that buttress the continent. Ice shelves have been undergoing major changes in recent decades, many of them collapsing. The presumption is that these events are caused by hydrofracturing and unusual wave forcing. We find that a main control on fracturing is the thickness of the ice mélange encased in and around preexisting rifts that penetrate the entire ice shelf thickness. If the ice mélange thins beyond a threshold value, the rifts reactivate and trigger iceberg calving. This process linking climate forcing and ice shelf retreat is missing from models and does not require hydrofracture.