bluuebunny/crossref_metadata_2025 huggingface dataset:
A Normalized Hysteretic Energy Spectrum for Energy-Based Seismic Design
Authors: Ma Cuiling , Chen Changbing , Lv Xiaotang , Bian Jian , Feng Yuan , Liu Hui
Published: October 2020

To disclose the impacts of hysteretic energy (HE) demand on energy-based seismic design, this paper introduces the dimensionless parameter βEH to express the cumulative HE indirectly and establishes the βEH spectrum for energy-based seismic design. After analyzing numerous seismic responses of a single degree-of-freedom (SDOF) system, the author set up a simplified βEH spectral formula based on the genetic algorithm. Then, 750 ground motion records were selected according to Chinese site classification, and used to examine the effects of soil type and damping ratio on the βEH spectra. The results show that the soil type, site group and damping ratio have significant effects on the βEH spectra; the ductility ratio has an impact on the spectral value but not the spectral shape.
A numerical study of flood effect of a bridge at tail of Ganjiang River, entrance of Poyang Lake
Authors: Ge Hua , Deng Chunyan
Published: October 2020

The construction of a river-crossing bridge will have an impact on the flow movement of the river section, which will bring adverse impact on flood control. In this paper, the influence of a planned bridge project on flood water level and flow field was analysed by using a two-dimensional mathematical model. The calculation results show that the construction of the bridge will cause backwater to the upstream of the bridge, resulting in the elevation of flood water level, thus bringing pressure to the use of flood control dam. At the same time, due to the squeezing effect of bridge piers on the flow, the flow velocity between piers and between piers and embankments on both sides will increase, which will bring adverse effects on the safe operation of the levee and pier.
System Safety Analysis and Fire Prevention Strategy of Public Entertainment Places
Authors: Ding Shifeng , Ding Nana
Published: October 2020

With the accelerated pace of Chinese economic development in recent years, the public entertainment industry is constantly developing, and the corresponding fire accidents are also on the rise, posing a huge threat to people’s lives and property. There are a lot of people gathering in public entertainment places, and it is difficult to evacuate people when a fire accident occurs. It is one of the key fire protection management areas. Fires in public entertainment places cause immeasurable losses to the lives and property safety of people. How to strengthen the fire protection work of public entertainment places is the key task of the fire management department. Based on the accident tree analysis method, this paper conducts a systematic safety analysis of the public entertainment industry and its typical fire cases, and concludes that the decoration of flammable and combustible materials and the storage of flammable and explosive materials are the main causes of fires in public entertainment places, and proposes fire prevention strategies.
Influence mechanism of congestion degree of layout on domino effect in petrochemical plants
Authors: Wenduo Huang , Xuechun Shao , Jiajie Wang , Yang Xiao , Dongliang Sun
Published: October 2020

The study focused on the establishment of the congestion degree in describing the layout of process plants, and discovering the influence mechanism of congestion degree on the risk of domino effect, in view of the fact that the congestion degree has not been used to represent the characteristics of petrochemical plant layout. A characterization model was built for the congestion degree of process plant layouts applying the theory of fuzzy model that it took safety distance, the amount of materials involved and the hazard of these substances into consideration, and came out with a membership function through logical calculus, which made congestion degree a comparable data. Secondly, a systematic domino effect risk analysis method was generalized on account of domino effect quantitative risk analysis method which include the equipment damage probability, the domino effect occurrence probability, risk analysis based on the consequences, individual risk index and social risk index, the process plant natural risk index and real risk index, and then these indices were compared to select the most suitable ones to illustrate the risk of domino effect and to research about part of the storage tank field of a petrochemical plant. Finally, the influence mechanism of layout congestion degree on domino effect of regional accident was obtained through this quantitative analysis. Simultaneously, a range of the congestion degree was acquired according to the individual risk index which can be used as a reference in the design stage of the process plant. The result proved that high congestion degree in process plant greatly increased the risk of domino effect in most of the quantitative risk analysis index, such as the probability of resulting in secondary accidents, the harm on both human and the equipments caused by the initial accident, and the individual risk and social risk, etc. The characterization models for the congestion degree and the domino risk analysis method established and summarized in the study have been applied in the design stage of process plant layout to optimize the layout, and thus reduce the risk of domino effect caused by accidents.
The Application of Third Generation Semiconductor in Power Industry
Authors: Zhang Yuqian
Published: October 2020

With the rapid development of technologies, the third generation semiconductor is being studied, as it is leading to the significant change in industry like the manufacture of PC, mobile devices, lighting etc. Till now, due to its irreplaceable physical characteristics, third generation semiconductor is applied to lots of fields. This paper analyzes the application of third generation semiconductor, namely, GaN and SiC. Their characteristics including advantages as well as disadvantages will be discussed through reviewing the result of relevant researches. Meanwhile, comparison between the third generation semiconductors and the second as well as the first generation semiconductors is made in this paper. Through the comparison of physical characteristics, recent marketing, production and limitations, the advantages and disadvantages of each semiconductor is analyzed and the suggestion of how to avoid the disadvantage through application is proposed. At last, the future development is predicted. According to the analysis result of this paper, silicon poses more merits. Silicon is not only cheaper but also performs better making it a preference of GaAs, and GaN in the domain of IC. The second generation semiconductor, GaAs, is widely used in the circuits and photoelectric integration. Furthermore, the third semiconductor material GaN is a promising material for power switching and communication and has the great possibility to play a crucial role in market.
Concise Definition of Aviation PNT User Requirements Based on OFD
Authors: Wang Yan , Zhao Wei , Yu Su , Shen YangHe
Published: October 2020

Definition of aviation is the core of PNT system requirements analysis and research, The quality of PNT user requirements definition will directly affect the scientificity and effectiveness of other research work of the system, QFD(Quality Function Deployment) is a systematic technical method and management method. In the process of product development, all activities are driven by users’ needs. QFD has been widely used in manufacturing, industrial and commercial military fields, and achieved great results. House of quality(HOQ) is the basic tool for establishing QFD system and essence of OFD method. The typical house of quality framework and analytical solution method can be used not only in the development process of new products, but also in the whole process of analysis in other fields. In this paper, aiming at the concise definition of PNT user requirements, QFD technology is used to build QFD model of PNT user requirements and PNT system technology based on the analysis of existing PNT information requirements and future aviation navigation development trend. In order to facilitate the analysis and simplify the approach of aviation navigation as the user requirements, and GNSS, SBAS, DEM, VOR, NDB, ILS and GBAS as the main system technologies. Finally, the technical quality house model of PNT system of aviation navigation task is given, so as to complete the concise definition of PNT user requirements of aviation users.
Gender Difference Analysis of Chinese Han Youth Based on Fingerprint Ridge Density
Authors: Xie Huawei , Lin Zifeng
Published: October 2020

Objective To discuss whether there are differences in fingerprint ridge density between the males and the females and what the specific differences are. Method A total of 120 males and 120 females (all were college students in Fujian) were selected, and the fingerprint ridge densities of these 240 Han youths were counted. According to Acree method, the radial upper part of the core region of the fingerprint center was selected for analysis, because the fingerprint pattern types in this region all presented similar ridges. This method was used to isolate the ridge in a certain area, so as to facilitate the counting. A 5mm×5mm grid was designated as a counting area on the middle radial part of the fingerprint for identification. Fingerprint ridges in the unit area were counted, then the average was calculated, and finally SPSS software was used to process and analyze all the data obtained. Result For the females, the average ten-fingerprint ridge density was basically above 14 ridges/ 25mm2; and for the males, it was basically below 14.5 ridges/25mm2. Conclusion There are some differences in the density of ten-fingerprints between men and the females, and the females’ is generally higher than that of the males.
Study on environmental impact of artificial horizontal freezing method in subway connecting passage
Authors: Yu Changyi , Lu Mingyue
Published: October 2020

When the subway is built in complex urban strata, especially when excavating near buildings, it is necessary to strictly control the freezing amount by adopting artificial freezing method. At present, the theoretical calculation is aimed at the frozen rise under ideal conditions, but for complex geological conditions, the simplified model results are difficult to meet the actual requirements. However, numerical calculation can adapt to complex strata and complex boundary conditions. Therefore, in this paper, the environmental impact of artificial horizontal freezing method in subway connecting passage is studied by numerical simulation, and the change of thermophysical parameters with the change of temperature field is considered in the simulation. The simulation method in this paper provides guidance for actual construction.
Research on the relationship between precipitation and landslide
Authors: Zhang Yubin
Published: October 2020

This paper introduces the inducing factors of landslide disaster and the terrain characteristics of landslide. The characteristics of landslides in southern and Western China are mainly introduced. The influence of vegetation covered slope soil on rainwater infiltration was studied. By analyzing the relationship between soil porosity and soil permeability, it can be used as a basis for assessing landslide risk. At the same time, the concept of soil and water cycle was introduced in combination with induced factors. These studies are of great significance for improving the accuracy of landslide warning in the future.
Based on the concept of “city double repair” under the application strategy of urban waste
Authors: wan Jiekun , wei xiaojuan
Published: October 2020

As an important part of the development and modernisation in China, the construction and development of urban landscape is always our focus. In the process of landscape design, urban waste is taking up space, and may also pollute the environment, however, some of the waste can be recycled and reused in construction. This paper provides certain strategies applied in the urban design to enlarge the material options and scenarios using the waste in order that these abandoned material can be recycled second time during cities’ construction thus realizes a sustainable development, with more avant-garde landscape conceptions and more valuable references.
The Linkage relationship between the development of secondary industry and environmental pollution: a case in Fujian
Authors: Ling GAO , Wenting JIANG
Published: October 2020

Fujian is very wealthy in natural resources, which provides a good environment for social development and people’s life. However, with the development of economy, environmental pollution has become an importation problem in Fujian. In order to discuss the linkage relationship between economic development and environmental pollution, this paper selects the data of the secondary industry, industrial waste gas emissions, industrial waste water emissions and industrial solid waste production from 1995 to 2017 in Fujian, establishes the VAR model, explore the relationship between the development of secondary industry and environmental pollution. The results show that the association between the development of the secondary industry and environmental pollution is monotonously increasing. The industrial waste gas has become the main pollutant restricting the development of the secondary industry. Industrial solid waste has made the largest contribution to the development of the secondary industry, indicating a positive dynamic correlation.
Influence of Root Morphology on Ecological Slope Protection
Authors: Xiaolei JI , Lanlan XU , Guoping YANG
Published: October 2020

Ecological slope protection is of great importance for preventing the water and soil loss on bare slopes, improving the ecological environment, and realizing the sustainable ecosystem development. The root-soil composite slope consisting of homogenous soil mass and oleander root system was taken as the study object. Based on the mechanics principle of soil reinforcement by roots in ecological slope protection, the influences of the lateral root quantity of plants and included angle between main root and lateral root on the slope protection were investigated via the finite element (FE) software ABAQUS. The simulation results show that the larger the quantity of lateral roots, the more obvious the displacement reduction of the soil mass on the slope surface will be. The slope protection effect varies with the root morphology, the included angle between main root and lateral root is an important factor influencing the slope protection effect of plants, and the slope protection effect at included angle of 30° is apparently superior to that at 90°. The research results can provide a theoretical support for the plant selection in the ecological slope protection.
Experimental investigation and constitutive modelling of the deformation behaviour of high impact polystyrene for plug-assisted thermoforming
Authors: Atmani Oualid , Abbès Fazilay , Li Yuming , Batkam Serge , Abbès Boussad
Published: October 2020

This paper concerns the experimental and numerical study of the plug-assisted thermoforming process of high impact polystyrene (HIPS). The thermomechanical properties of this polymer were characterized at different temperatures and deformation rates. To study the influence of different parameters in the real conditions of plug-assisted thermoforming process, we carried out “plug-only” tests at different temperatures and plug velocities. To model the deformation behaviour of HIPS, we proposed a thermo-elastic-viscoplastic model, which we have implemented in Abaqus software. A thermo-dependent friction model was also proposed and implemented in Abaqus software. The parameters of the proposed models were identified by the inverse analysis method in the real conditions of plug-assisted thermoforming. The proposed models were validated with “plug-only” tests and plug-assisted thermoforming of yogurt container.
Tauchtauglichkeitsuntersuchungen an Bord von Kreuzfahrtschiffen
Authors: Grannemann Julia J. , Vahlbruch Bettina
Published: October 2020

Der Trend zum Gerätetauchen besteht auch bei Kreuzfahrtgästen, die häufig spontan in ihrem Urlaub einen Tauchschein erwerben wollen. Es handelt sich nicht nur um junge, gesunde Gäste, sondern auch um Gäste mit Vorerkrankungen und um Kinder und Erwachsene über 40 Jahre. Wir beleuchten Möglichkeiten und Grenzen der Durchführung von leitliniengerechten Tauchtauglichkeitsuntersuchungen an Bord von Kreuzfahrtschiffen. Wenn an Bord eine Lungenfunktion und ein Ruhe-EKG durchgeführt werden können, ist von tauchmedizinisch qualifizierten Schiffsärzten die Beurteilung und Attestierung der Tauchtauglichkeit von Gästen bis 39 Jahren möglich. Bei Gästen über 40 Jahren sollte keine Tauchtauglichkeit attestiert werden, wenn die vorgeschriebene Belastungsergometrie an Bord nicht durchgeführt werden kann. Daher empfehlen wir aus für den Arzt rechtlichen Gründen und für den Gast zur gesundheitlichen Sicherheit auf die Ausstellung einer Tauchtauglichkeit für Gäste ab 40 Jahren zu verzichten, wenn die Voraussetzung der Durchführung einer Belastungsergometrie nicht vorliegt.
COVID-19-Ausbruch an Bord eines Kreuzfahrtschiffs
Authors: Rieke Burkhard
Published: October 2020

Gegenwärtig werden vielfach die Regelungen zur Eindämmung der SARS-CoV-2-Pandemie wieder zurückgenommen, auch mit dem Wunsch, Urlaubsreisen als Wirtschaftsfaktor wiederzubeleben. Dabei werden Kreuzfahrten besonders kritisch beurteilt, was die Gefährdung von Passagieren und Crew durch COVID-19 angeht. Das liegt zum einen an der relativen Enge der Unterbringung und Versorgung an Bord, zum anderen an dem unglücklichen Beispiel der „Diamond Princess“, der ab 03.02.2020 in Yokohama/Japan trotz COVID-19-Fällen an Bord keine Evakuierung sämtlicher Passagiere gestattet wurde 1.
Malaria, ist das ein Fluch oder kommt das von einer Mücke?
Authors: Albanus Celina , Albanus Dirk Robert
Published: October 2020

Fernab von touristischen Pfaden im nordöstlichen Bundesstaat Loreto, Distrikt Urarinas, befindet sich der im Jahre 1998 vom deutschen „Freundeskreis Indianerhilfe e. V.“ (FKI) gegründete Gesundheitsposten, der sich der Versorgung der indigenen Gruppe der Urarina verschrieben hat. Nachbarschaft: Urwald und Wasser. Bevölkerung: Moskitos (Abb. 1). Die nächste Einkaufsmöglichkeit ist 6 h flussabwärts in einem kleinen Dorf an der Mündung des Río Chambira in den Río Marañón, der später zum Amazonas wird. Ein richtiges Krankenhaus findet sich erst wieder in der Hauptstadt des Bundesstaats, Iquitos, etwa 200 km Luftlinie entfernt, entsprechend etwa 24 h reiner Fahrtzeit mit einem 25-PS-Außenborder – Fernstraßen gibt es keine, die Wege können nur auf dem Wasser zurückgelegt werden (Abb. 2).
Weltweit erste Parabelflugkampagne unter den Bedingungen der SARS-CoV-2-Pandemie
Authors: Ullrich Oliver
Published: October 2020

Am 11. Juni 2020 startete vom Militärflugplatz Dübendorf die 4th Swiss Parabolic Flight Campaign unter der Leitung der Swiss SkyLab Foundation und des Innovationsclusters Luft- und Raumfahrt der Universität Zürich. Es handelte sich um die weltweit erste Parabelflugkampagne während der SARS-CoV2-Pandemie. In Europa und den USA waren zu dieser Zeit alle Parabelflug-Forschungskampagnen abgesagt oder verschoben. Mit der 4th Swiss Parabolic Flight Campaign konnte in der Praxis gezeigt werden, dass alle erforderlichen Schutzmaßnahmen implementierbar sind und es keinen Grund gibt, große und komplexe Forschungsflugmissionen unter der SARS-CoV-2-Pandemie nicht durchzuführen.
Überlegenheit von Artemisininkombinationen über Chinin in allen Trimestern
Authors: Früh Jonas
Published: October 2020

Die Malaria tropica ist nach wie vor eine führende Ursache für Morbidität und Mortalität bei schwangeren Frauen. Allein in Subsahara-Afrika infizieren sich jährlich rund 11 Mio. Schwangere, wobei eine Malariainfektion in der Gravidität sowohl das Leben der Mutter als auch das Wohl der ungeborenen Kinder gefährdet. Die konsequente Behandlung einer Malaria ist darum speziell in dieser Patientengruppe essenziell, um Schäden an der Mutter sowie dem Fötus zu vermeiden. Dabei müssen mögliche Nebenwirkungen von Medikamenten – insbesondere teratogene Effekte – vermieden werden.
An Open Source Solution for “Hands-on” teaching of PET/CT to Medical Students under the COVID-19 Pandemic
Authors: Biermann Martin , Kanoun Salim , Davidsen Trond , Gray Robert
Published: October 2020

Aims Since 2017, medical students at the University of Bergen were taught PET/CT “hands-on” by viewing PET/CT cases in native format on diagnostic workstations in the hospital. Due to the COVID-19 pandemic, students were barred access. This prompted us to launch and evaluate a new freeware PET/CT viewing system hosted in the university network.

Methods We asked our students to install the multiplatform Fiji viewer with Beth Israel PET/CT plugin (http://petctviewer.org) on their personal computers and connect to a central image database in the university network based on the public domain orthanc server (https://orthanc-server.com). At the end of course, we conducted an anonymous student survey.

Results The new system was online within eight days, including regulatory approval. All 76 students (100 %) in the fifth year completed their course work, reading five anonymized PET/CT cases as planned. 41 (53 %) students answered the survey. Fiji was challenging to install with a mean score of 1.8 on a 5-point Likert scale (5 = easy, 1 = difficult). Fiji was more difficult to use (score 3.0) than the previously used diagnostic workstations in the hospital (score 4.1; p < 0.001, paired t-test). Despite the technical challenge, 47 % of students reported having learnt much (scores 4 and 5); only 11 % were negative (scores 1 and 2). 51 % found the PET/CT tasks engaging (scores 4 and 5) while 20 % and 5 % returned scores 2 and 1, respectively.

Conclusion Despite the initial technical challenge, “hands-on” learning of PET/CT based on the freeware Fiji/orthanc PET/CT-viewer was associated with a high degree of student satisfaction. We plan to continue running the system to give students permanent access to PET/CT cases in native format regardless of time or location.
Iodothiophenes and Related Compounds as Coupling Partners in Copper-Mediated N-Arylation of Anilines
Authors: Bentabed-Ababsa Ghenia , Picot Laurent , Mongin Florence , Bouarfa Salima , Erb William , Thiéry Valérie , Roisnel Thierry , Dorcet Vincent
Published: October 2020

N-Arylation of various 2-acylated anilines with different electron-rich heteroaryl iodides (2- and 3-iodothiophenes, 2- and 3-iodobenzothiophenes­, 2-iodobenzofuran) was achieved by using activated copper and potassium carbonate in dibutyl ether at reflux. The reactivity of the different heteroaryl iodides and anilines employed was discussed and rationalized on the basis of their electronic features. Subsequent cyclization by aromatic electrophilic substitution easily took place in the case of C2-free (benzo)thienyl or C3-free (benzo)furyl derivatives­, affording original tri- and tetracycles. The antiproliferative activity of most of them was evaluated in A2058 melanoma cells and revealed four chlorinated tetracycles as effective growth inhibitors.
Shuddering Attacks in an Infant
Authors: Koul Roshan
Published: October 2020

Shuddering attacks are rare benign nonepileptic paroxysmal events (NEPEs) seen in infancy and early childhood. These movements may look like myoclonus or infantile spasms. Recognition of these movements is important to avoid elaborate workup and antiepileptic medications. Shuddering attacks disappear by the age of 2 years in most of these children. NEPEs are almost as common as epilepsy. It is easy to differentiate the common NEPEs from epilepsy. However, it is difficult to diagnose the rare benign NEPEs not seen before. Shuddering attacks are one of these rare NEPEs. It is commonly diagnosed as infantile spasms/myoclonus unless one observes the actual event or video very carefully.
Inkjet printing multilayered reflectins thin films for bioelectronics
Authors: Frank Jodi Ackerman
Published: October 2020

Researchers use inkjet printing to fabricate the proton-conductive layers of proteins derived from squid.
Bayesian optimization for inverse problems in time-dependent quantum dynamics
Authors: Deng Z. , Tutunnikov I. , Averbukh I. Sh. , Thachuk M. , Krems R. V.
Published: October 2020

We demonstrate an efficient algorithm for inverse problems in time-dependent quantum dynamics based on feedback loops between Hamiltonian parameters and the solutions of the Schrödinger equation. Our approach formulates the inverse problem as a target vector estimation problem and uses Bayesian surrogate models of the Schrödinger equation solutions to direct the optimization of feedback loops. For the surrogate models, we use Gaussian processes with vector outputs and composite kernels built by an iterative algorithm with the Bayesian information criterion (BIC) as a kernel selection metric. The outputs of the Gaussian processes are designed to model an observable simultaneously at different time instances. We show that the use of Gaussian processes with vector outputs and the BIC-directed kernel construction reduces the number of iterations in the feedback loops by, at least, a factor of 3. We also demonstrate an application of Bayesian optimization for inverse problems with noisy data. To demonstrate the algorithm, we consider the orientation and alignment of polyatomic molecules SO2 and propylene oxide (PPO) induced by strong laser pulses. We use simulated time evolutions of the orientation or alignment signals to determine the relevant components of the molecular polarizability tensors. We show that, for the five independent components of the polarizability tensor of PPO, this can be achieved with as few as 30 quantum dynamics calculations.
Effect of imposed shear on the dynamics of a contaminated two-layer film flow down a slippery incline
Authors: Sani Muhammad , Selvan Siluvai Antony , Ghosh Sukhendu , Behera Harekrushna
Published: October 2020

The linear instability of a surfactant-laden two-layer falling film over an inclined slippery wall is analyzed under the influence of external shear, which is imposed on the top surface of the flow. The free surface of the flow and the interface among the fluids are contaminated by insoluble surfactants. Dynamics of the fluid layers are governed by the Navier–Stokes equations, and the surfactant transport equations regulate the motion of the insoluble surfactants at the interface and free surface. Instability mechanisms are compared by imposing the external shear along and opposite to the flow direction. A coupled Orr–Sommerfeld system of equations is derived using the perturbation technique and normal mode analysis. The eigenmodes corresponding to the Orr–Sommerfeld eigenvalue problem are obtained by employing the spectral collocation method. The numerical results imply that the stronger external shear destabilizes the interface mode instability. However, a stabilizing impact of the external shear on the surface mode is noticed if the shear is imposed in the flow direction, which is in contrast to the role of imposed external shear on the surface mode for a surfactant-laden single layer falling film. Furthermore, in the presence of strong imposed shear, the overall stabilization of the surface mode by wall velocity slip for the stratified two-fluid flow is also contrary to that of the single fluid case. The interface mode behaves differently in the two zones at the moderate Reynolds numbers, and higher external shear magnifies the interfacial instability in both zones. An opposite trend is observed in the case of surface instability. Moreover, the impression of shear mode on the primary instability is analyzed in the high Reynolds number regime with sufficiently low inclination angle. Under such configuration, dominance of the shear mode over the surface mode is observed due to the weaker impact of the gravitational force on the surface instability. The shear mode can also be stabilized by applying the external shear in the counter direction of the streamwise flow. Conclusively, the extra imposed shear on the stratified two-layer falling film plays an active role in the control of the attitude of the instabilities.
Computationally efficient complex envelope approximate Crank–Nicolson scheme and its open region problem for anisotropic gyrotropic plasma
Authors: Wu Peiyu , Xie Yongjun , Jiang Haolin , Niu Liqiang , Natsuki Toshiaki
Published: October 2020

By incorporating a complex envelope (CE) method, higher order formulation, and approximate Crank–Nicolson (CN) procedure, unconditionally stable complex frequency shifted perfectly matched layer (CFS-PML) implementation is proposed for anisotropic gyrotropic plasma bandpass simulation in open region problems. More precisely, the CE based higher order CN approximate-factorization-splitting (AFS) PML implementation is introduced to terminate the unbounded finite-difference time-domain (FDTD) lattice. The proposed implementation can not only improve computational efficiency but also enhance the absorption at boundaries during the whole bandpass simulation. Numerical examples which include plasma slab models and ridge waveguide structures are introduced to further demonstrate accuracy, absorption, and efficiency. It can be concluded in the results that our proposal can achieve considerable performance in modeling bandpass signals, improving computational efficiency, enhancing absorption, and maintaining remarkable accuracy. Meanwhile, it can be observed that the proposed implementation is stable when the time step surpasses far beyond the Courant–Friedrichs–Lewy condition.
Water pumping performance of a Cryo–TMP combination pump
Authors: Lee Dong-Ju , In Sang-Ryul , Park Chong-Yun
Published: October 2020

There is an increasing need to systematically investigate the performance of commercial Cryo–TMP [in-line Cryogenic Water Pump (CWP) + Turbo Molecular Pump (TMP)] combination pumps. In this study, the factors affecting the pumping speed of water in a Cryo–TMP, such as the number of cold rings, dimensions, shape, etc., are systematically analyzed by Monte Carlo simulation. We constructed a test dome and a Cryo–TMP500 based on the simulation results to measure the strict effective pumping performance of the Cryo–TMP. In addition, we established a systematic measurement method for pumping performance using the Cryo–TMP500 in three experimental modes: TMP-only mode, CWP-off mode, and CWP-on mode. The results show that the water pumping speed of the Cryo–TMP500 with only one cold ring is ∼76% of that of a standalone cryopump (∼30 000 L/s) with the same opening inlet diameter; this speed is 22 550 L/s, which is in good agreement with the simulation result of 23 276 L/s. The pumping speeds for non-condensable gases (H2, N2) are 8%–19% higher than expected.
Effect of collisions on the shape of the coherent population trapping resonance detected by the Ramsey method
Authors: Voloshin G.V. , Barantsev K.A. , Litvinov A.N.
Published: October 2020

We report on a theoretical model of the effect of coherent population trapping in alkali atoms in an optically thin gas cell with a buffer gas at a nonzero temperature in a pulsed laser field. The shape of the Ramsey resonance is analysed for two different temperature ranges, i. e. for a ‘cold’ atomic ensemble and for an ensemble of ‘hot’ atoms in a cell with a buffer gas. The influence of the hyperfine structure of the excited level on the shift of the central Ramsey resonance is investigated.
Thermal detector for measuring radiation parameters of pulsed lasers and generators of submillimetre and millimetre ranges
Authors: Kik M.A. , Sigov A.S. , Shilyaev A.A. , Zav’yalov V.V.
Published: October 2020

A theoretical formula is derived that makes it possible to establish a relationship between the speed and sensitivity of bolometers with geometric and thermophysical parameters of the receiving element and substrate. The result is confirmed by a preliminary (evaluation) experiment. The proposed thermal detectors can record and measure the radiation power of lasers and generators of the submillimetre (SMM) and millimetre (MM) ranges.
Study of the behaviour of the light field orbital angular momentum upon astigmatic mode conversion
Authors: Volostnikov V.G.
Published: October 2020

We consider the behaviour of the orbital angular momentum of the light field as a superposition of Hermite – Gaussian beams upon astigmatic mode conversion. An analytical expression is obtained for the orbital angular momentum of such fields. Expressions are found for various linear combinations of Hermite – Gaussian beams. The astigmatic mode conversion of the initial light fields that are equivalent from the point of view of the orbital angular momentum is shown to lead to significantly different final results.
Evaluation of temperature changes in a cell culture plate well with absorbing walls containing a 3D model of tumour spheroid under irradiation in the optical range
Authors: Sapogova N.V. , Yuzhakova D.V. , Smirnov A.A. , Shirmanova M.V. , Lukina M.M. , Gavrina A.I. , Izosimova A.V. , Zagaynova E.V. , Kamensky V.A.
Published: October 2020

The temperature conditions for photodynamic therapy of the culture of tumour cells organised in 3D spheroids are studied. The spheroids are placed in the cell culture medium in the well of a special cell culture plate with absorbing walls. A mathematical model is presented that describes the temperature distribution in a well with a cell culture plate heated by optical radiation. It is shown that the temperature in the well volume is not uniformly distributed, and the temperature on the well surface can differ significantly from the temperature in its volume.
Lidar-based remote infrared gas sensor for monitoring anthropogenic pollution: a proof of concept
Authors: Meshcherinov V.V. , Spiridonov M.V. , Kazakov V.A. , Rodin A.V.
Published: October 2020

We propose using wavelength-modulation laser absorption spectroscopy in combination with quadrature detection of scattered light for remote industrial pollution monitoring in the atmosphere with a compact lidar-based gas sensor, which can be mounted on board an unmanned aerial vehicle. The instrument can be used for detecting leaks in product pipe lines; monitoring toxic gases near landfill sites, waste incineration plants, and other hazardous man-made facilities; analysing the gas atmosphere in industrial buildings and structures; and monitoring engineering processes at a sensitivity level of tens of ppm m in gas concentration measurements at characteristic distances of tens of metres.
Frequency comb generation in WGM microsphere based generators for telecommunication applications
Authors: Braunfelds J. , Murnieks R. , Salgals T. , Brice I. , Sharashidze T. , Lyashuk I. , Ostrovskis A. , Spolitis S. , Alnis J. , Porins J. , Bobrovs V.
Published: October 2020

We review the frequency comb generation process, main microresonator parameters such as free spectral range (FSR) and Q-factor, previously used optical frequency comb (OFC) generator parameters and resulting frequency combs, as well as the implementation of OFC for optical data transmission. An optical frequency comb is produced in a setup based on a tapered fibre and a SiO2 microsphere. The generated frequency comb has a frequency spacing of 2 nm or 257 GHz. During the fabrication of a tapered fibre from SMF28, use is made of the transmission signal to control the taper pulling process. The final measured tapered fibre transmission is ∼96%. A microsphere whispering gallery-mode resonator (WGMR), exhibiting a Q-factor of at least 2 × 107, is fabricated from an optical fibre with a thicker core than SSMF. Moreover, for future experiments, a frequency comb generator based on a free-space setup consisting of lenses, a prism, and a microsphere is developed, and the Q-factor dependence on different distances between the prism and the microsphere is investigated.
Final report of supplementary comparison for APMP.QM-S7.1: methane in nitrogen at 2000 μmol/mol
Authors: Hong K , Kim B M , Bae H K , Lee S , Tshilongo J , Mogale D , Seemane P , Mphamo T , Kadir H A , Ahmad M F , Nasir N H A , Baharom N , Soni D , Singh K , Bhat S , Aggarwal S G , Johri P
Published: October 2020

Methane is one of the major greenhouse gases that affect climate change. To mitigate anthropogenic CH4 emissions effectively, it is necessary to measure and monitor CH4 emissions from the production and transport of fossil fuels. Therefore, it is important for NMIs to demonstrate measurement equivalence for the standard gases of CH4.

This is the third comparison on methane in nitrogen or air. The first comparison is the key comparison of CCQM-K82 (ambient level methane in air) and the second comparison is the supplementary comparison of APMP.QM-S7 (2000 μmol/mol methane in nitrogen). As a supplementary comparison, the purpose of this comparison is to study the comparability of CH4 standard gas mixtures at emission level (0.05 cmol/mol - 0.5 mol/mol in nitrogen or air). Furthermore, this comparison can provide a link to APMP.QM-S7 through KRISS who participated in both previous comparisons. In this comparison, KRISS prepared gas standards and sent to participants. Each participant measured the standard on their laboratory and reported their measurement results to KRISS according to the measurement protocol.

This report describes the results of a supplementary comparison for methane in nitrogen at 2000 μmol/mol.

Main text

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.

The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Electronic structures and band alignment transition in double-wall MoS2/WS2 nanotubes for optoelectronic applications
Authors: Guo Dan , Yang Kaike , Zhang Cai-Xin , Shen Tao , Deng Hui-Xiong
Published: October 2020

Band alignment caused by discontinuous band structures of two different materials plays a central role in semiconductor heterojunctions and interface physics. We investigate the electronic structures and band alignments of double-wall MoS2/WS2 nanotubes with different chirality and geometry. We find that the band gap of both armchair and zigzag nanotubes obeys

E

G

=

E

G

in

−

exp

−
δ

Δ
R
−
α

,

with

E

G

in

being the band gap of the inner nanotube and

Δ
R

the spacing distance between the inner and outer nanotubes. When placing MoS2 in the inner and WS2 in the outer of the nanotubes, the band alignment belongs to type-I because the conduction band minimum (CBM) of the inner MoS2 nanotube is lower than that of the outer WS2 nanotube, and the valence band maximum (VBM) of MoS2 nanotube is higher than that of WS2 nanotube. While putting the WS2 nanotube in the inner and MoS2 nanotube in the outer, the CBM and VBM of MoS2 nanotube are both lower than the corresponding band extreme points of WS2 nanotube when their diameter is small. Therefore, type-II to type-I band alignment transition occurs, originating from charge transfer with increasing spacing distance. Due to the adjustable band gap and electronic structures, we expect that these double-wall hetero-structured nanotubes will have great potential in optoelectronic devices.
Super-resolution and optical sectioning integrated structured illumination microscopy
Authors: Dan Dan , Gao Peng , Zhao Tianyu , Dang Shipei , Qian Jia , Lei Ming , Min Junwei , Yu Xianghua , Yao Baoli
Published: October 2020

Super-resolution structured illumination microscopy (SR-SIM) has attracted a great deal of attention in the past few decades. As a wide-field imaging technique, SR-SIM usually suffers from issues relating to out-of-focus background, particularly when imaging thick samples. In this study, we develop an integrated SIM with simultaneous SR and optical sectioning (OS) capabilities, facilitating SR imaging of stacked optical sections, with the out-of-focus background suppressed. The combination of the merits of SR and OS is realized by means of a new image reconstruction algorithm. We confirm the validity of the integrated SIM, both experimentally and in simulation. We anticipate that this integrated SIM will assist biologists in obtaining much clearer SR images in relation to thick specimens.
Supervised learning in Hamiltonian reconstruction from local measurements on eigenstates
Authors: Cao Chenfeng , Hou Shi-Yao , Cao Ningping , Zeng Bei
Published: October 2020

Reconstructing a system Hamiltonian through measurements on its eigenstates is an important inverse problem in quantum physics. Recently, it was shown that generic many-body local Hamiltonians can be recovered by local measurements without knowing the values of the correlation functions. In this work, we discuss this problem in more depth for different systems and apply supervised learning method via neural networks to solve it. For low-lying eigenstates, the inverse problem is well-posed, neural networks turn out to be efficient and scalable even with a shallow network and a small data set. For middle-lying eigenstates, the problem is ill-posed, we present a modified method based on transfer learning accordingly. Neural networks can also efficiently generate appropriate initial points for numerical optimization based on the BFGS method.
The status of the radiation safety culture within the higher education, research and teaching sectors in the UK
Authors: Coldwell T , Cole P , Dorling S , Hunter J , Mott G , Murdock C , Whitcher R , Willis S
Published: October 2020

This article reports on the research by a working group, comprising members from the Association of University Radiation Protection Officers, on the radiation safety culture in the UK higher education, research and teaching (HERT) sectors. The impetus for this research arises from the work of the International Radiation Protection Association and their emphasis that embedding radiation safety culture within an organisation is the most effective way of delivering the standards of radiation safety and security that society expects. The deficiency in radiation safety culture has been a large contributor to major nuclear disasters, such as Chernobyl and Fukushima Daiichi. The working group designed an online survey aimed at higher education students, higher education academics, and researchers. The survey did not try to obtain an indication of safety performance, but of people’s views on behaviours and attitudes of radiation safety that reflect the current radiation safety culture in their organisation. The findings of the survey are reported in this article along with a discussion of the analysis and recommendations for improving radiation safety culture. The responses from the survey strongly indicate that the radiation safety culture in UK HERT sectors has worrying shortfalls, particularly in communication and training.
Polymer-assisted TEM specimen preparation method for oxidation-sensitive 2D materials
Authors: Köster Janis , Liang Baokun , Storm Alexander , Kaiser Ute
Published: October 2020

By structural and analytical TEM and scanning electron microscopy experiments we show that atomically-resolved structural characterization of oxidation-sensitive two-dimensional material is strongly hindered when the final step of the preparation process, the transfer to the TEM grid, is performed with a wet etching method involving bases or acids, interacting with the highly reactive sample surface. Here we present an alternative polymer-assisted and mechanical-exfoliation-based sample preparation method and demonstrate it on selected oxidation-sensitive transition metal phosphorus trisulfides and transition metal dichalcogenides. The analysis, obtained from the samples prepared with both of the methods clearly show that oxidation is the origin of discrepancy, the oxidation during the final preparation step is strongly reduced only when the new method is applied, and atomically-resolved structural characterization of the pristine structures is now possible.
pH-dependent fluorescence of thiol-coated CdSe/CdS quantum dots in an aqueous phase
Authors: Lesiak Anna , Banski Mateusz , Halicka Kinga , Cabaj Joanna , Żak Andrzej , Podhorodecki Artur
Published: October 2020

The results presented in this paper show how the optical properties and colloidal stability of quantum dots (QDs) vary depending on pH conditions. For this investigation, as-synthesized hydrophobic CdSe/CdS QDs were transferred to an aqueous medium by surface modification with 3-mercaptopropionic acid. The ligand exchange procedure was applied under three different pH conditions: acidic, neutral and alkaline, to obtain three kinds of hydrophilic QDs dispersed in phosphate buffer. The efficiency of the functionalization of QDs was estimated based on the changes in ABS and the highest value was obtained under acidic conditions (45%). The efficiency of photoluminescence (PL) was also best preserved under these conditions, although it was 30 times less than the PL of hydrophobic QDs. Then, all three kinds of hydrophilic QDs were dispersed in solutions with a wide range of pH (2–12) and investigated by absorbance and PL measurements. The results show that QDs subjected to a ligand exchange procedure are characterized by intensive PL at the selected pH values, which correspond to pKa of the ligand. This phenomenon is independent of the pH at which the ligand exchange procedure is conducted. Moreover, it was found that the PL intensity is preserved during the experiment for QDs functionalized under neutral conditions, whereas it decreases for acidic and increases for alkaline conditions.
Test–retest reliability of the two-point discrimination test on the sole of the foot in people with multiple sclerosis
Authors: Taylor S C , Atkinson G , Dixon J , Robinson J R , Ryan C G
Published: October 2020

Background: Two-point discrimination (TPD) is an assessment of tactile acuity. People with multiple sclerosis (MS) can have reduced foot sole tactile acuity, which has been linked to impaired balance. Objective: To quantify the test–retest reliability of TPD on the sole of the foot in people with MS. Approach: 41 participants (32 females), with mean (SD) age of 60 (9) years, and Expanded Disability Status Scale of <7.5, had their TPD measured at the head of the first metatarsal and the heel on two occasions, 2–14 d apart. Mean systematic change, within-subjects SD, limits of agreement (LOA), coefficient of variation and the intraclass correlation coefficient (ICC) were quantified as point estimates (95% CI). Main results: Systematic learning effects were evident. The within-subjects SD at the metatarsal and the heel was 6.7 mm (5.5–8.6) and 8.3 mm (6.7–10.8), and the LOAs were 18.6 mm (15.2–24.) and 23.7 mm (18.7–30.1), respectively. ICCs for metatarsal and heel was 0.87 (0.76–0.93) and 0.90 (0.80–0.95), respectively, but these were likely inflated by sample heterogeneity. Significance: In people with MS, TPD on the sole of the foot has an adequate test–retest reliability for research purposes, but there is substantial measurement variability for individual patients.