bluuebunny/crossref_metadata_2025 huggingface dataset:
N/O abundance ratio and the progenitor mass for the most luminous planetary nebulae of M 31
Authors: Ueta Toshiya , Otsuka Masaaki
Published: October 2022

Context. Plasma diagnostics form the basis of investigation into the physico-chemical properties of line-emitting gaseous systems.

Aims. To perform plasma diagnostics properly, it is essential to accurately correct the input spectrum for extinction because determining the degree of extinction is dependent on the physical properties of the line-emitting gas. Hence, both extinction correction and plasma diagnostics have to be performed simultaneously and self-consistently.

Methods. By comparing the results of analyses performed for a sample of nine bright planetary nebulae in M 31, both with and without the fully iterative self-consistent simultaneous extinction correction and plasma diagnostics, we demonstrate how a seemingly benign initial assumption of the physical conditions of the line-emitting gas in extinction correction could compromise the results of the entire analyses in terms of the extinction, electron density and temperature, and ionic and elemental abundances.

Results. While the electron density and temperature are relatively immune to the imposed inconsistent assumptions, the compromised extinction would cause systematic offsets in the extinction-corrected spectrum, and hence, line strengths, which consequently would impose adverse effects on the resulting ionic and elemental abundances, and other inferences made from the incorrect results.

Conclusions. We find that this M 31 PN sample simply represents those around the high-mass end of the mass range for low-mass planetary nebula progenitor stars as expected from the existing theoretical models. It appears that the suspicion raised in the previous study – that these PNe could be anomalously nitrogen-overabundant for the expected progenitor mass range – is simply caused by the apparent underestimation in extinction that originates from the imposed inconsistent assumptions in extinction correction. In a larger context, the results of plasma diagnostics in the literature that are done without seeking simultaneous self-consistency with extinction corrections have to be handled with caution. Ideally, such previous results should be re-evaluated by always seeking simultaneous self-consistency.
Effects of road slope on emission characteristics for a heavy-duty diesel vehicle based on engine-in-the-loop methodology
Authors: Li Su , Wang Xiaowei , Gao Tao , Huo Yongzhan , Lu Yang , Wang Mingda
Published: October 2022

A dump truck with a maximum designed total mass of 24500 kg was selected to measure the emission characteristics of pollutants and carbon dioxide (CO2) under fully-loaded and unloaded conditions at the same simulated road with different road slope, same driver and vehicle model by using the engine-inthe- loop methodology. The results show that driving at gradient road will result in an increase in power and total emissions. The brake specific emissions of gaseous pollutant and CO2 are lower at gradient road, while the brake emission of particle number are higher at gradient road. Road slope affects exhaust temperature so as to affect nitrogen oxide (NOx) emissions. Under unloaded conditions, long-slope conditions are more likely to cause an increase in NOx emissions.
Well Trajectory Measurement Error Based on Gyro Survey
Authors: Diao Binbin , Zhang Yan , Gao Deli , Liu Zhe
Published: October 2022

Gyroscopic survey technology is one of the key technologies to promote the progress of directional drilling technology. It is of great practical significance to study the error of well trajectory measurement based on gyro surveys and identify the main error sources. This paper introduces the error sources which lead to the uncertainty of borehole position in gyroscopic survey, six gyroscopic survey error models, and the calculation model of the contribution rate of the error sources to the error ellipse. The differences between gyro and MWD survey errors and the main error sources of gyro surveys are investigated with an example. The results show that gyroscopic surveys cannot reduce the uncertainty of borehole position compared to MWD surveys in the environment without magnetic interference. The static measurement by a three-axis gyro inclinometer is more beneficial for the improvement of the measurement accuracy of the borehole position. The error sources that contribute to the measurement error of the well trajectory are also different in the vertical section, build-up section, and horizontal section. Unlike the main error source of the MWD survey, the g-dependent error sources of the gyro sensor significantly contribute to the measurement error of the borehole trajectory. Therefore, the measurement error of the well trajectory can be significantly reduced by improving the gyroscope survey tool and reducing the influence of spin mass unbalance.
Design scheme of metal wastewater purification device in industrial park
Authors: Wang Tianqi , Dong Fangchen , Xiang Peiling , He Shanshan , Wang Tielin
Published: October 2022

Due to the limitation of chemical process technology and management system, the traditional treatment mode of heavy metal waste liquid pollution has many problems, such as high power consumption in the process, high wear of consuming steel, high management cost, and secondary pollution caused by complex solid waste residue in data detection. Team based on the front end of deep learning module and backend soft measurement model of collaborative structures, design and improvement of the learning algorithm combined with nested integration depth control series new front end treatment module, the successful implementation of heavy metal ions in industrial wastewater concentration of accurate prediction, and according to the predicted results and the analysis of liquid ingredients, targeted treatment after intelligent classification.
Improvement and application of drilling fluid technology for gas exploration wells in Yanchi block
Authors: Wang Hao , Wei Yan
Published: October 2022

Currently, the exploration and development scope of Changqing oilfield has gradually developed to edge blocks and deep systems, typically of Yanchi block. However, in the construction process, there are some problems such as poor well wall stability, frequent well leakage and prominent collapse contradiction, which seriously restricts the increase of drilling speed. In this paper, the measures such as well structure optimization, system formulation optimization, separate management of collapse and leakage, refined performance control, and pressure-bearing leakage plugging were taken by a combination with the construction situation in 2021 so as to improve drilling speed and reduce the complexity of downhole failures.
The effect of injection speed on the law of heavy oil initiation and seepage flow research
Authors: Zhu Jiajia , Liu Jing , Li Zhengbin , Jiang Yimin , Jiang Zhihao , Liu Xiujie , Zhao Zhiqiang
Published: October 2022

In order to make the heavy oil flow, the repulsion pressure gradient should be larger than the start-up pressure gradient. The results show that the smaller the injection speed is, the smaller the start pressure gradient is, and the subsequent seepage process has a smaller and smoother replacement pressure gradient, and there is an effective limit of the start pressure gradient. Using the non-stationary method to calculate the relative oil-water permeability and water saturation, the bound water saturation does not differ much with increasing injection speed, and the residual oil saturation increases. Therefore, in order to start the heavy oil more easily in the mine production can be started at a lower production rate, the study of injection speed is important for the heavy oil start-up and development effect.
Study on reservoir physical properties of Nadanhada terrane
Authors: Qu Guohui , Li Xiunan , Tian Xuebin , Zhang Zilu , He Weizhong , Li Bowen , Liu Yikun , Wang Fengjiao , Shen Anqi
Published: October 2022

The Nadanhada terrane is basically a large tectonic sedimentary hybrid, which is an accretionary complex belt formed by the subduction of the Pacific plate to the Eurasian plate. Through field geological survey, paleomagnetic analysis, paleontological analysis and microscopic observation of core slices, its structural and petrological characteristics were studied. The results show that the accretionary complex is mainly composed of 7 parts, including undeformed sedimentary rocks, shear deformed sedimentary rocks, shear deformed volcanic rocks, turbidites, deformed siliceous rocks, limestone blocks and basic ultrabasic rocks. Shear deformation structures of deformed sedimentary rocks and volcanic rocks are developed. The sediment grain size of the Lower Cretaceous reservoirs in each basin in the northern region is relatively coarse, the sorting is moderately deviated, and the rounding is poor, mainly secondary to angular. The grain size of the lower Cretaceous sediments of each basin in the southern region is relatively fine, with coarse, medium and fine sandstones, but mainly medium fine sandstones, with medium sorting preference and sub angular to sub round roundness.
Evaluation of operation regulation ability of a power plant unit in heating season
Authors: Lao Jinxu , Zhang Hu , Zhu Lingkai , Zhang Yangpeng , Lv Haizhen
Published: October 2022

In order to further improve the operation level of thermal power units directly regulated by the power grid, the regulation capacity of a power plant unit is comprehensively analyzed and evaluated from the aspects of heating capacity, minimum startup mode of the whole plant, heating state and load capacity, etc., to provide support for the accurate dispatching of the unit.
Identification of potential CCUS clusters and its pipeline network optimization in China
Authors: Wang Pengtao , Wu Xi , Ge Gangke , Wang Xiaoyan , Wang Haifeng , Zhang Yang , Wang Wei , Yan Xi , Zheng Yan , Miao Yongbin , Wang Bing
Published: October 2022

Climate change is a huge challenge facing the world. Carbon Capture, Utilization and Storage (CCUS) is an important technology that is expected to ensure the continued safe and large-scale use of fossil energy under the pressure of climate change in China. However, the current CCUS project has a large initial investment, and it is difficult to realize the commercialization of CCUS technology. The development of CCUS cluster centers can effectively reduce the overall investment of CCUS projects, which is the development trend of CCUS projects. This study identified 20 coal-fired power plant cluster centers and 6 oil and gas field gathering and transportation centers by utilizing Chinese coal-fired power plant data and oil and gas field data. Finally, the CO2 pipe network between the cluster centers is planned. This study provides data and research methods for identifying potential CCUS clusters and storage and transportation centers in China. It can provide a theoretical reference for further research on the matching site selection of CO2 transport pipelines and CO2 sources and sinks in China.
Application of UAV technology in environmental impact assessment of mine reclamation project
Authors: He Jiaxin , Zhang Zhuo , Xie Xinyu
Published: October 2022

It is of great significance to carry out environmental impact assessment on the renovated mining area for the assessment of reclamation benefits. The maturing of UAV technology brings new possibilities for environmental assessment. Aiming at the problem of insufficient environmental impact assessment system of mining area renovation project, this paper constructs the environmental impact assessment system of mining area renovation project, and puts forward a set of scheme to carry out the environmental impact assessment of mining area after reclamation based on the data obtained by UAV platform. The research results have certain value for the benefit assessment of comprehensive renovation and ecological reclamation of mining area
Analysis of reducing pressure and increasing injection in high pressure water injection block of low permeability reservoir
Authors: Wu Qiong
Published: October 2022

The plugging phenomenon near the well zone of oil injection well will seriously affect the water injection development of oil field, and then affect the exploitation of oil resources. The water injection development of low permeability reservoir is affected by various factors. Due to the large difference between layers and the serious interference between layers, the physical property of oil layer is relatively poor, and the water injection pressure shows a trend of increasing year by year, which has a great impact on the development of oil resources. As the oilfield development benefit is not ideal, it is necessary to take reasonable measures to reduce the pressure of water injection to ensure the effect of water injection to improve the recovery of the reservoir. At present, the technology has been mature, which can reduce the pressure of water injection and ensure the oil recovery rate. The application in several oil Wells has verified the correctness of this conclusion.
Analysis of low permeability reservoir development technology
Authors: Su Feng
Published: October 2022

As an important energy source for social production and development, oil is non-renewable. In the process of development and utilization, attention should be paid to continuously improve the exploitation technology, enhance the ability of oil exploration, and strengthen the development of low permeability reservoir resources, so as to provide sufficient oil resources for social production and development. However, low permeability reservoir resources have their own characteristics and are limited by multiple factors in the process of exploitation. It is difficult to improve the exploitation efficiency of low permeability reservoir resources without adopting corresponding exploitation technology. This it is scientific and reasonable exploitation of low permeability oil reservoir resources technology are analyzed and discussed, in the comprehensive analysis based on the characteristics of low permeability oil reservoirs, mining characteristics, puts forward the well pattern optimization, waterflood recovery, fracturing technology and mining method, working for the effective implementation of the low permeability reservoir development provides the technical support, also need to continue well technology application in the construction process in the future.
Geological and geochemical characteristics and genesis of carbonate rocks in a certain area
Authors: Zhang Tong
Published: October 2022

Carbonate rock is a general term for the rock composed of carbonate minerals, which is mainly composed of carbonate sediments, with calcite (limestone) and dolomite (dolomite) as the main forms. Carbonate rocks are important oil storage rocks, storing more than half of the world's natural gas and oil, and co-existing with various types of solid sedimentary deposits. They are themselves a kind of mineral that can be used in construction, chemical industry, metallurgy and other processes, so they have very important economic value. This paper analyzes the geological and geochemical characteristics and genesis of carbonate rocks in a certain area in order to provide theoretical support for related work.
Suitability assessment of carbon dioxide storage sites in sedimentary basins
Authors: Wang Pengtao , Wu Xi , Ge Gangke , Wang Xiaoyan , Wang Haifeng , Zhang Yang , Wang Wei , Yan Xi , Zheng Yan
Published: October 2022

The assessment of the suitability of CO2 storage sites is the basis for large-scale deployment of Carbon Capture Utilization and Storage (CCUS) projects. However, the research on the suitability of CO2 in sedimentary basins is relatively lagging behind in China. Previous studies have focused on CO2 storage sites, while social, economic and environmental factors are ignored. This paper takes counties and districts as the research objects, and conducts a comprehensive evaluation of onshore sedimentary basins. The research results show that: (1) Onshore sedimentary basins cover 839 counties (districts) in China, of which 318 counties (districts) are prohibited from implementing CO2 storage; 286 counties (districts) are Class II environmental risk areas; The suitable and suitable areas include 217 and 19 counties (districts) respectively, accounting for about 45% of the total onshore storage area. (2) The suitable and relatively suitable areas are mainly distributed in the Tarim Basin, the central and northern parts of the Songliao Basin, the northwestern part of the Ordos Basin, the northeastern part of the Erlian Basin, and the central and southern parts of the Bohai Bay Basin. Forbidden areas and general suitable areas are mainly distributed in Sichuan Basin, Jianghan-Dongting Basin, North Jiangsu Basin, northeastern Bohai Bay Basin, and southern Songliao Basin. This study establishes a method for assessing the suitability of CO2 storage sites, and gives a suitable area for CO2 storage in China, which provides a method and basis for the site selection of large-scale deployment of CCUS projects in China.
The reform direction of property right system of natural resources assets in China format
Authors: Zhong Xiaoyong , Guo Dongyan
Published: October 2022

The reform of property right system of natural resources is the only way to promote the construction of ecological civilization in China. By systematically combing the construction process of China’s natural resources assets property rights system and drawing lessons from foreign property rights system experience, this paper can systematically analyze the main problems faced by China’s natural resources assets system at present, and put forward targeted policy suggestions for reform.
Geological recognition and potential analysis of D block
Authors: Man Hongmei
Published: October 2022

Under the guidance of petroleum geology, on the basis of in-depth understanding of the geological characteristics of D block such as structure and sedimentation and the law of oil and gas enrichment, this paper discusses the reservoir potential of D block and selects the target block. The study shows that D block is a fault nose structure controlled by reverse normal fault, and the fault has a controlling effect on its provenance, reservoir formation and oil and gas distribution.
Research hotspots and trends in heritage building information modeling: A review based on CiteSpace analysis
Authors: Zhang Ziyi , Zou Yiquan
Published: October 2022

The year 2022 marks the 50th anniversary of the signing of the Convention Concerning the Protection of World Cultural and Natural Heritage. Heritage building information modeling (HBIM), which is a digital method of conserving architectural heritage, has recently received a great deal of attention from researchers, planners, and policy-makers in related fields around the world. However, there is not yet a complete analysis of the hot spots and trends in this area of research, nor has a complete workflow based on the practical application of HBIM been developed. In this article, we analyzed the research progress, hot spots, and trends in HBIM since 2010. We used the CiteSpace scientometric analysis tool to analyze 372 documents with high relevance to HBIM from the Web of Science core database using literature co-citation analysis, keyword co-occurrence analysis, cluster analysis, and keyword emergence detection. The findings show that research in the field of HBIM was still in the conceptualization stage during 2010–2017, and with the continuous development of various technologies, attention to HBIM has gradually accelerated since 2017 by expanding its uses to multidisciplinary fields such as artificial intelligence. In the cluster analysis of literature co-citations, 14 clusters were generated, and four clusters, semiautomatic 3D modeling, heritage information system, pilot study, and virtual reality, which have high rates of citation, are discussed in this paper. These clusters reflect the hot spots and frontiers of research in HBIM to a certain extent. In the “Discussion” section, a systematic and complete workflow of HBIM application to heritage architecture is proposed for three levels: modeling, data exchange, and auxiliary management. On this basis, the development of the field of heritage building conservation and sustainable development is analyzed to provide valuable theoretical and practical references to propose future research directions.
On local quantum Gibbs states
Authors: Duboscq Romain , Pinaud Olivier
Published: October 2022

We address in this work the problem of minimizing quantum entropies under local constraints. We suppose that macroscopic quantities, such as the particle density, current, and kinetic energy, are fixed at each point of Rd and look for a density operator over L2(Rd), minimizing an entropy functional. Such minimizers are referred to as local Gibbs states. This setting is in contrast with the classical problem of prescribing global constraints, where the total number of particles, total current, and total energy in the system are fixed. The question arises, for instance, in the derivation of fluid models from quantum dynamics. We prove, under fairly general conditions, that the entropy admits a unique constrained minimizer. Due to a lack of compactness, the main difficulty in the proof is to show that limits of minimizing sequences satisfy the local energy constraint. We tackle this issue by introducing a simpler auxiliary minimization problem and by using a monotonicity argument involving the entropy.
Yield degradation mechanisms for two-shock capsules evaluated through simulations
Authors: Bradley P. A. , Haines B. M. , Kyrala G. A. , MacLaren S. A. , Salmonson J. D. , Pino J. E. , Mackay K. K. , Peterson R. R. , Yi A. , Yin L. , Olson R. E. , Krasheninnikova N. , Batha S. H. , Kline J. L. , Sauppe J. P. , Finnegan S. M. , Pak A. , Ma T. , Dittrich T. R. , Dewald E. L. , Khan S. F. , Sayre D. , Tommasini R. , Ralph J. E. , Field J. E. , Masse L. , Tipton R. E. , Mackinnon A. J. , Benedetti L. R. , Nagel S. R. , Bradley D. K. , Celliers P. M. , Berzak Hopkins L. , Izumi N. , Kervin P. , Yeamans C. , Hatarik R. , Hartouni E. P. , Turnbull D. P. , Chen K. C. , Hoover D. E.
Published: October 2022

An investigation of twenty two-shock campaign indirectly driven capsules on the National Ignition Facility was conducted using the xRAGE computer code. The two-shock platform was developed to look at the sensitivity of fuel–ablator mix with shock timing, asymmetry, surface roughness, and convergence on roughly ignition size scale capsules. This platform used CH/CD (plastic/deuterated plastic) shell capsules that were about 685-μm outer radius and filled with D2 or hydrogen-tritium (HT) gas. The experimental radius and velocity vs time, neutron yield, burn averaged ion temperature (Tion), burn width, and self-emission image size were compared to one-dimensional (1D) and two-dimensional (2D) simulations. Our 2D simulations suggest that the mixing of glass from the fill tube was the dominant source of impurity in the gas region of the capsule during burn, along with fuel–ablator mix. The mass of glass mixed in is about 5–10 ng. Our 2D simulations capture most of the yield trends from different degradation mechanisms, and they match the observed burn width and Tion measurements. Our 2D models match all the available data to within 2.5 times the normalized experimental error for 19 of 20 capsules.
Upgraded main ion charge exchange recombination spectroscopy on the C-2W field reversed configuration (FRC) plasma
Authors: Marshall Ryan S. , Gupta Deepak K. , Leinweber Hannes , Aviles Juan , Nations Marcel , Sweeney James ,   TAE Team
Published: October 2022

A prototype main-ion CHarge Exchange Recombination Spectroscopy (mCHERS) diagnostic is providing measurements of the main-ion (hydrogen or deuterium) temperature and velocity in the C-2W field reversed configuration plasma using charge exchange Balmer-alpha emission at five different radial locations with 500 Hz frequency and a per-pixel velocity resolution of 15 km/s. Measurement along the entire plasma radius of C-2W is enabled by a diagnostic neutral beam (DNB) that passes through the center of plasma, unlike the larger diameter heating neutral beams that have impact parameters of 20 cm. DNB provides high time resolution via beam modulation and spatial resolution via its small cross section. The goals of the current mCHERS upgrade are to double the number of spatial channels, improve the per-pixel velocity resolution by three times, and increase the measurement frequency to match the maximum modulation frequency of the diagnostic neutral beam (∼10 kHz). To accomplish these goals, a new astigmatism-free Isoplane spectrometer has been commissioned. Progress and results from the newly upgraded mCHERS system are detailed.
Development of a flat-field-response, four-channel x-ray imaging instrument for hotspot asymmetry studies
Authors: Xu Jie , Zhang Xing , Mu Baozhong , Chen Liang , Li Wenjie , Xu Xinye , Li Mingtao , Wang Xin , Dong Jianjun , Wang Feng , He Junhua
Published: October 2022

Here, we describe a flat-field-response, four-channel x-ray imaging instrument developed to study hotspot asymmetries in inertial-confinement fusion experiments. We discuss the details of its design and optical characterization, the diagnostic deployment of the device, and experiments with it. We achieved a spatial-response flatness better than ∼8.4% within a ±200 µm field of view (FOV), with a spatial resolution of ∼4 µm at the center of the FOV. We used the system to characterize the low-order asymmetry of the implosion hotspot, and we obtained improved results after adjustments to improve the irradiation symmetry. Due to the flat-field-response characteristic, the versatile instrument also has the potential to be applied to diagnostics for the hotspot electron temperature and the Rayleigh–Taylor instability.
Aluminum Frenkel defects cause hysteresis in Al2O3/AlGaN capacitors
Authors: Deretzis I. , Fiorenza P. , Fazio T. , Schilirò E. , Lo Nigro R. , Greco G. , Fisicaro G. , Roccaforte F. , La Magna A.
Published: October 2022

Al 2 O 3 /AlGaN metal-oxide-semiconductor capacitors show a hysteretic behavior in their capacitance vs voltage characteristics, often attributed to near-interface traps deriving from defects within the oxide layer. The origin as well as the structural/electronic properties of such defects are still strongly debated in the literature. Here, we use ab initio molecular dynamics and the climbing-image nudged elastic band method to show that aluminum Frenkel defects give rise to bistable trap states in disordered and stoichiometric Al2O3. Based on these results, we propose a calibrated polaron model representing a distribution of individually interacting energy levels with an internal reconfiguration mode and coupled to continuous bands of carriers to explain the hysteresis mechanism in Al2O3/AlGaN capacitors.
An overset boundary condition-enforced immersed boundary method for incompressible flows with large moving boundary domains
Authors: Zhao Xiang , Yang Liming , Xu Chang , Shu Chang
Published: October 2022

Conventional immersed boundary methods (IBMs) have greatly simplified the boundary condition treatment by interpreting boundaries as forces in the source terms of governing equations. In conventional IBMs, uniform meshes of very high resolution must be applied near the immersed boundary to treat the solid–fluid interface. However, this can induce a high computational cost for simulating flows with large moving boundary domains, where everywhere along the trajectory of the moving object must be refined isotropically. In the worst scenario, a global refinement is required when the object is moving arbitrarily in the entire computational domain. In this work, an overset boundary condition-enforced immersed boundary method (overset BC-enforced IBM) is proposed to simulate incompressible flows with large moving boundary domains efficiently. In the proposed overset BC-enforced IBM, a locally refined uniform mesh is applied and fixed on the moving object to account for the local motions, e.g., the rotation and deformation of the object, while the global motion of the object is handled by embedding the locally refined mesh in a coarser background mesh. Both the local mesh and the global background mesh can be generated automatically using the Cartesian approach to avoid the cumbersome boundary treatment. Since the mesh refinement is local, considerable computational savings can be achieved. The overset BC-enforced IBM is combined with the lattice Boltzmann flux solver to simulate various fluid–structure interaction problems with rigid and deformable boundaries.
Polaronic defects in monolayer CeO2: Quantum confinement effect and strain engineering
Authors: Zhang Ling , Zhi Guo-Xiang , Meng Qingling , Dou Wenzhen , Hua Chenqiang , Sun Lu , Zhou Miao
Published: October 2022

We uncover the structure, stability, and electronic properties of polaronic defects in monolayer (ML) CeO2 by means of first-principles calculations, with special attention paid to the quantum confinement effect induced by dimensionality reduction. Results show that the polaron can be more stabilized in ML CeO2 than in the bulk, while formation of oxygen vacancy (Vo2+) and polaron–vacancy complexes [(Vo2+-1polaron)1+, (Vo2+-2polaron)0] tends to be more difficult. The polaronic defect states sit deeper in energy within the bandgap of ML CeO2 compared to the bulk case. We further demonstrate that the epitaxial strain in ceria film, as normally exists when grown on metal substrate, plays a crucial role in regulating the defect energetics and electronic structures. In particular, the formation energies of polarons, Vo2+, (Vo2+-1polaron)1+, and (Vo2+-2polaron)0, generally decrease with tensile strain, leading to controllable defect concentration with strain and temperature. This study not only provides physical insights into the polaronic defects in ultrathin oxide films, but also sheds light on their potential technological applications in nanoelectronics, fuel cells, and catalysts.
Intermolecular vibrational states of HF trimer from rigorous nine-dimensional quantum calculations: Strong coupling between intermolecular bending and stretching vibrations and the importance of the three-body interactions
Authors: Felker Peter M. , Bačić Zlatko
Published: October 2022

We present the computational methodology that allows rigorous and efficient nine-dimensional (9D) quantum calculations of the intermolecular vibrational states of noncovalently bound trimers of diatomic molecules, with the monomers treated as rigid. The full 9D vibrational Hamiltonian of the trimer is partitioned into a 3D “frame” (or stretching) Hamiltonian and a 6D “bend” Hamiltonian. These two Hamiltonians are diagonalized separately, and a certain number of their lowest-energy eigenstates is included in the final 9D product contracted basis in which the full 9D intermolecular vibrational Hamiltonian is diagonalized. This methodology is applied to the 9D calculations of the intermolecular vibrational levels of (HF)3, a prototypical hydrogen-bonded trimer, on the rigid-monomer version of an ab initio calculated potential energy surface (PES). They are the first to include fully the stretch-bend coupling present in the trimer. The frequencies of all bending fundamentals considered from the present 9D calculations are about 10% lower than those from the earlier quantum 6D calculations that considered only the bending modes of the HF trimer. This means that the stretch-bend coupling is strong, and it is imperative to include it in any accurate treatment of the (HF)3 vibrations aiming to assess the accuracy of the PES employed. Moreover, the 9D results are in better agreement with the limited available spectroscopic data that those from the 6D calculations. In addition, the 9D results show sensitivity to the value of the HF bond length, equilibrium or vibrationally averaged, used in the calculations. The implication is that full-dimensional 12D quantum calculations will be required to obtain definitive vibrational excitation energies for a given PES. Our study also demonstrates that the nonadditive three-body interactions are very significant in (HF)3 and have to be included in order to obtain accurate intermolecular vibrational energy levels of the trimer.
Not waiting for the death knell: a pilot study to examine supplementation and survivorship in a declining population of Tasmanian eastern quoll (Dasyurus viverrinus)
Authors: Hamer Rowena P. , Robinson Natasha , Brewster Rob , Barlow Molly , Guinane Morrigan , Humphrey Morgan , Mifsud Adrian , Hamilton David G. , Kutt Alex S.
Published: October 2022

Tasmanian populations of the eastern quoll (Dasyurus viverrinus) represent the last wild stronghold of this species after its extirpation from the Australian mainland, but they have experienced declines of more than 50% over the past three decades. We investigated the feasibility of supplementing wild populations with captive-bred individuals in attempts to halt and reverse observed declines in Tasmanian populations. We released 20 captive-bred eastern quolls into an extant wild population in the Tasmanian central plateau, and monitored their short-term survival, dispersal and body condition. We recorded high initial survival and low initial dispersal of captive-bred individuals relative to previous release attempts in unfenced areas of mainland Australia. Further work to determine long-term survival of released individuals, and the genetic and population-level impacts on local populations is ongoing. Our preliminary results support the use of population supplementation as an effective conservation action, which allows for early intervention to address species declines while testing hypotheses about their underlying causes.
Effects of germination on the energy value of cereal grains for livestock
Authors: Black J. L. , Tredrea A. M. , Bird S. H. , Hughes R. J. , Nielsen S. G.
Published: October 2022

Context Unusually wet weather in eastern Australia during the 2021 spring resulted in prolonged preharvest germination of a large proportion of cereal crops. An estimated 40–45% of wheat grown in New South Wales was downgraded from human consumption to feed-wheat. Similarly, preharvest germination of barley renders it unsuitable for malting or brewing. Aims To investigate the impact of wheat grown in 2021 and of various germination times on the energy value of cereal grain species for different livestock types. Methods Twenty-three samples of wheat harvested in 2021 were evaluated. Three experiments were also conducted with increasing germination times, as follows: (1) grain from wheat, barley and sorghum cultivars were germinated for 0–100 h; (2) sorghum grain was steeped in water and germinated for 5 or 10 days, with different periods of ensiling to simulate grain ‘reconstitution’ as practiced in cattle feedlots; (3) barley, wheat, sorghum and triticale grain was germinated for 0, 20 or 48 h and fed to meat chickens. Experiments 1 and 2 were conducted in vitro, with starch disappearance, starch digestion by animal-derived enzymes and starch fermentation by rumen microbes measured. Key results Short-term germination did not affect grain starch content within a cultivar, increased animal enzyme digestion of starch for barley, but not for wheat or sorghum. Longer germination of sorghum grain for 5–10 days substantially increased starch fermentability, which was further enhanced by anaerobic ensiling. Germination significantly increased the available-energy content of barley grain, but not wheat, sorghum or triticale for meat chickens. Conclusions The energy content of preharvest germinated grains for animals was not decreased, but increased for barley fed to chickens and for sorghum fed to ruminants after 5 days of germination. Implications Feeding preharvest germinated grains to livestock does not reduce energy availability, but may lead to fungal growth and mycotoxin formation.
The effects of Heisenberg constraint on the classical cross sections in proton hydrogen collision
Authors: Ziaeian Iman , Tőkési Károly
Published: October 2022

The interaction between a proton and a ground state hydrogen atom is studied using a standard three-body classical trajectory Monte Carlo (CTMC) and a quasi-classical trajectory Monte Carlo (QCTMC) model where the quantum feature of the collision system is mimicked using the model potential in the Hamiltonian as was proposed by Kirschbaum and Wilets (1980 Phys. Rev. A 21 834). The influence of the choice of the model potential parameters (α, ξ) on the initial radial and momentum distribution of the electron are analyzed and optimized. We found that although these distributions may not be as close to the quantum results as the distribution of standard CTMC results, we can find the combination of the (α, ξ) where the calculated cross sections are closer to the experimental data and closer to the results obtained quantum mechanically. We show that the choice of 3 < α < 5 is reasonable. To validate our observation, we present cross sections for ionization, excitation, charge exchange (CX), and state selective CX to the projectile bound state. Calculations are carried out in the projectile energy range between 10 and 1000 keV amu−1.
Driving induced ergodicity breaking in a kinetic constraint quantum system
Authors: Dai C M , Zhang Yunbo , Yi X X
Published: October 2022

Periodically driving an interacting many-body system generically leads to a featureless ergodic phase, in which the memory of initial condition is completely erased in the long time limit. Here we study the quantum East model under periodic driving, and show that the strength of the kinetic constraint can be effectively tuned by manipulating the driving amplitude when the driving frequency is high enough. Using numerical simulations, we find that there is a driving induced ergodic to non-ergodic phase transition for high frequency driving and a wide range of driving amplitude. For driven system in the non-ergodic phase, it exhibits slow dynamics and the localization of excitation. Our findings show the possibility of engineering long live Floquet states in translation-invariant quantum systems.
The theory of transport in helical spin-structure crystals
Authors: Zadorozhnyi Andrei , Dahnovsky Yuri
Published: October 2022

We study helical structures in spin-spiral single crystals. In the continuum approach for the helicity potential energy the simple electronic band splits into two non-parabolic bands. For low exchange integrals, the lower band is described by a surface with a saddle shape in the direction of the helicity axis. Using the Boltzmann equation with the relaxation due to acoustic phonons, we discover the dependence of the current on the angle between the electric field and helicity axis leading to the both parallel and perpendicular to the electric field components in the electroconductivity. The latter can be interpreted as a planar Hall effect. In addition, we find that the transition rates depend on an electron spin allowing the transition between the bands. The electric conductivities exhibit nonlinear behaviors with respect to chemical potential µ. We explain this effect as the interference of the band anisotropy, spin conservation, and interband transitions. The proposed theory with the spherical model in the effective mass approximation for conduction electrons can elucidate nonlinear dependencies that can be identified in experiments. We find the excellent agreement between the theoretical and experimental data for parallel resistivity depending on temperature at the phase transition from helical to ferromagnetic state in a

M
n
P

single crystal. In addition, we predict that the perpendicular resistivity abruptly drops to zero in the ferromagnetic phase.
Shape memory polymer composites (SMPCs) using interconnected nanowire network foams as reinforcements
Authors: Chen Yixi , Kazerooni Nazanin Afsar , Srinivasa Arun , Chapkin Wesley A , Sihn Sangwook , Roy Ajit K , Vaddiraju Sreeram
Published: October 2022

Shape memory polymers (SMPs), although offer a suite of advantages such as ease of processability and lower density, lag behind their shape memory alloy counterparts, in terms of mechanical properties such as recovery stress and cyclability. Reinforcing SMPs with inorganic nanowires and carbon nanotubes (CNTs) is a sought-after pathway for tailoring their mechanical properties. Here, inorganic nanowires also offer the added advantage of covalently binding the fillers to the surrounding polymer matrices via organic molecules. The SMP composites (SMPCs) thus obtained have well-engineered nanowire-polymer interfaces, which could be used to tune their mechanical properties. A well-known method of fabricating SMPCs involving casting dispersions of nanowires (or CNTs) in mixtures of monomers and crosslinkers typically results in marginal improvements in the mechanical properties of the fabricated SMPCs. This is owed to the constraints imposed by the rule-of-mixture principles. To circumvent this limitation, a new method for SMPC fabrication is designed and presented. This involves infiltrating polymers into pre-fabricated nanowire foams. The pre-fabricated foams were fabricated by consolidating measured quantities of nanowires and a sacrificial material, such as (NH4)2CO3, followed by heating the consolidated mixtures for subliming the sacrificial material. Similar to the case of traditional composites, use of silanes to functionalize the nanowire surfaces allowed for the formation of bonds between both the nanowire-nanowire and the nanowire-polymer interfaces. SMPCs fabricated using TiO2 nanowires and SMP composed of neopentyl glycol diglycidyl ether and poly(propylene glycol) bis(2-aminopropyl ether) (Jeffamine D230) in a 2:1 molar ratio exhibited a 300% improvement in the elastic modulus relative to that of the SMP. This increase was significantly higher than SMPC made using the traditional fabrication route. Well-known powder metallurgy techniques employed for the fabrication of these SMPCs make this strategy applicable for obtaining other SMPCs of any desired shape and chemical composition.
A spin modulating device, tuned by the Fermi energy, in honeycomb-like substrates periodically stubbed with transition-metal-dichalkogenides
Authors: Belayadi Adel , Vasilopoulos Panagiotis
Published: October 2022

We investigate spin transport through graphene-like substrates stubbed vertically with transition-metal-dichalcogenides (TMDs). A tight-binding model is used based on a graphene-like Hamiltonian that includes different types of spin–orbit coupling (SOC) terms permitted by the C
3v
symmetry group in TMDs/graphene-like heterostructures. The results show a spin modulation obtained by tuning the strength and sign of the Fermi energy E

F
and not by varying the SOC strength as is mainly the case of Datta and Das. The spin conductance is directly controlled by the value of E

F
. In addition, a perfect electron-spin modulation is obtained when a vertical strain is introduced. In this case, the spin conductance exhibits a strong energy dependence. The results may open the route to a combination of graphene-like substrates with TMD stubs and the development of spin-transistor devices controlled by the Fermi energy rather than the SOC strength.
Solvothermal synthesis of nitrogen-doped carbon quantum dots for the sensitive detection of azithromycin
Authors: Zhou Zhilin , Li Zhiwen , Wang Jianghua , Wu Zhichuan , Fu Yingqiang
Published: October 2022

Abstracts

Carbon quantum dots are widely used in various drug detection applications because of their excellent photoluminescence properties. However, there are few reports about the detection of macrolide antibiotics. In this work, blue emitting nitrogen-doped carbon quantum dots (N-CQDs) were synthesized by using a hydrothermal method, which exhibit the most prominent emission band at 464 nm at an excitation wavelength of 414 nm. And it was found that Cu2+ alone or the macrolide antibiotic azithromycin had no significant effect on the fluorescence intensity of N-CQDs. Still, when the two were mixed, they quenched the fluorescence of N-CQDs. Based on this, a fluorescence assay for azithromycin were developed. The fluorescence of the mixture of N-CQDs and Cu2+ showed good linearity with azithromycin (0.52–42.2 μM) with a low detection limit of 0.52 μM.
Self-assembly for preparing nanotubes from monolayer graphyne ribbons on a carbon nanotube
Authors: Song Bo , Cai Kun , Shi Jiao , Qin Qing-Hua
Published: October 2022

Graphyne nanotube (GNT), as a promising one-dimensional carbon material, attracts extensive attention in recent years. However, the synthesis of GNT is still challenging even in the laboratory. This study reveals the feasibility of fabricating a GNT by self-assembling a monolayer graphyne (GY) ribbon on a carbon nanotube (CNT) via theoretical and numerical analysis. Triggered by the van der Waals force from the CNT, a GY ribbon near the tube first winds upon the tube and then conditionally self-assembles to form a GNT. The self-assembly process and result are heavily influenced by the ambient temperature, which indicates the thermal vibration of the nanosystem. Molecular dynamic simulation results address the temperature range conducive to successful self-assembly. Different types of GNTs, e.g. α-, β-, and γ-GNTs with specified chirality (armchair, zigzag, and chiral), length, and radius, can be obtained via self-assembly by controlling the geometry of the GY ribbons and temperature. The present theoretical understanding is helpful for fabricating GNTs with predefined morphology.
Benchmark of a self-consistent dynamic 1D divertor model DIV1D using the 2D SOLPS-ITER code
Authors: Derks G L , Frankemölle J P K W , Koenders J T W , van Berkel M , Reimerdes H , Wensing M , Westerhof E
Published: October 2022

This paper presents DIV1D, a new 1D dynamic physics-based model of the divertor plasma under development to study and control the dynamics of detached plasmas. An innovative feature of DIV1D is that it mimics cross-field transport using an effective flux expansion and includes a neutral gas background outside the divertor leg. We outline a 1D mapping procedure for static 2D SOLPS-ITER simulations of divertor plasmas in the Tokamak á Configuration Variable, which can be used to benchmark 1D codes. For DIV1D good agreement is found for the most important divertor plasma quantities along the leg (e.g., densities temperature, heat flux, and velocity) both in a qualitative and quantitative sense. In addition, the comparison with SOLPS-ITER demonstrates that DIV1D self-consistently captures the evolution of divertor plasma quantities in the main heat flux channel as a function of the upstream plasma density in a scan from 2 to

3
×

10

19

m

−
3

. The agreement is ascribed to the unique account of cross-field transport in DIV1D with an effective flux expansion and the interaction with an external neutral gas background.