bluuebunny/crossref_metadata_2025 huggingface dataset:
Geographic differentiation of adaptive phenological traits of barnyardgrass (Echinochloa crus-galli) populations
Authors: Martinková Zdenka , Honěk Alois , Pekár Stano , Leišova-Svobodová Leona
Published: February 2021

In central Europe, barnyardgrass [Echinochloa crus-galli (L.) P. Beauv.], has commonly been found in humid lowland areas. As a result of the introduction of new crops and farming practices, in the northwest Carpathians, E. crus-galli has spread from lowland (<200 m altitude) to highland (>400 m altitude) areas. We collected seed samples from local populations lying at a distance of approximately 5 km from each other and lined up along transects following the flows of two rivers. The rivers first flow through the valleys separated by mountain ridges and eventually flow into a common lowland. After ripening, the seeds of all populations were germinated at 25 C under long-day conditions. Only the seeds of some lowland populations germinated up to 75%. The frequency of germinated seeds decreased as the altitude where the population was collected increased, and above 200 m above sea level, germination was mostly zero. We then studied the phenological and morphological differentiation of plants from the original (lowland) and recently occupied (highland) areas. Seeds of the lowest and the highest localities lying on the transect of each river were sown in a common garden experiment. In plants from the highland localities, heading and seed dispersal were earlier, while tiller height and tiller mass were lower than in plants from the lowland localities. Seed mass produced per tiller in the lowland and highland plants was similar, and as a result, highland plants allocated a larger proportion of body mass to seed production than did lowland plants. Echinochloa crus-galli populations from highland localities thus produce their progeny earlier and at a lower energy cost than populations from lowland localities. The plasticity of phenological characters likely facilitated adaptation during E. crus-galli spread from lowlands to highlands. Similar adaptations in plant phenology may contribute to the spread of E. crus-galli in other geographic areas.
Particle Dynamics in a Managed Navigation Channel Under Different Tidal Conditions as Determined Using Multiple Radionuclide Tracers
Authors: Wang Jinlong , Huang Dekun , Xie Weiming , He Qing , Du Jinzhou
Published: February 2021

Particle dynamics play significant roles in sedimentological and geomorphological processes as well as biogeochemical cycles in estuaries. We collected a suite of water samples from the North Passage of the Changjiang (Yangtze) Estuary during different tidal conditions in summer 2009 to observe variations in the particulate 234Th, 7Be, 210Pb, and 137Cs activities as well as in particle transport, deposition, and resuspension. The mean activities of 7Be and 210Pbex in surface water during low tide were lower than those during high tide. The residence times of 7Be (1.1–3.4 d), 234Th (4.7–28 d), and 210Pb (7.9–34 d) in the North Passage increased with the increase of salinity and suspended particulate matter. The estimated results, based on a two‐dimensional model of 7Be, 234Th, and 210Pb, showed that sedimentary particles in the North Passage experienced net deposition during neap tides whereas those in more seaward areas of the North Passage exhibited net resuspension during spring tides. The 7Be/210Pbex activity ratio in seaward area of the North Passage was lower during spring tide than during neap tide but both were close to values in surface sediments beyond the estuary. Using 7Be/210Pbex and 137Cs/210Pbex activity ratios as tracers, we deduced that most of particles in the North Passage were not derived from the direct deposition of Changjiang input particles but were transported from sediment deposited offshore. These results emphasized the important contributions of offshore inputs to sediments in this channel, which should be considered when conducting channel dredging of other estuarine systems.
The Distribution of Frosts on Mars: Links to Present‐Day Gully Activity
Authors: Khuller A. R. , Christensen P. R. , Harrison T. N. , Diniega S.
Published: February 2021

Numerous types of activity in mid latitude martian gullies have been observed over the last decade. Some activity has been constrained to occur in the coldest times of year, suggesting that surficial frosts that form seasonally and diurnally might play a key role in this activity. Here we use thermal infrared data to explore the global, spatial and temporal variation of temperatures conducive to CO2 and H2O frost formation on Mars, and assess their distribution relative to gully landforms. CO2 frost detections are observed at all latitudes and are strongly correlated with dusty, low thermal inertia regions near the equator. While it is difficult to accurately detect the formation of H2O frost, the global H2O frost point distribution generally follows water vapor column abundance, and is weakly correlated with surface pressure. Most global CO2 frost detections do not contain gullies, but 47% of all gullies, and 73% of active gullies (76% in the south, and 25% in the north) do overlap with CO2 frost detections. We predict that the conditions necessary for significant present‐day gully activity include a few centimeters of CO2 frost within loose, unconsolidated sediments (I ∼ 300 ) on relatively steep (>20°) slopes. Additionally, it could be possible for small amounts of H2O frosts to play a role in present‐day equatorial mass wasting events. However, whether present‐day gully activity is representative of gully formation is still open to debate, because it seems unlikely that frosts can erode channels into rocky substrates–even considering geologic timescales.
Impacts of the urinary sodium-to-potassium ratio, sleep efficiency, and conventional risk factors on home hypertension in a general Japanese population
Authors: Hirata Takumi , Kogure Mana , Tsuchiya Naho , Miyagawa Ken , Narita Akira , Nochioka Kotaro , Uruno Akira , Obara Taku , Nakamura Tomohiro , Nakaya Naoki , Metoki Hirohito , Kikuya Masahiro , Sugawara Junichi , Kuriyama Shinichi , Tsuji Ichiro , Kure Shigeo , Hozawa Atsushi
Published: February 2021

Recently, a high urinary sodium-to-potassium (Na/K) ratio and reduced sleep efficiency, in addition to conventional risk factors (obesity and excess alcohol intake), have been identified as risk factors for hypertension. We estimated the population attributable fraction (PAF) for home hypertension due to these risk factors in a general Japanese population. We conducted a cross-sectional study including 1384 participants (393 men and 991 women) to estimate the odds ratio (OR) and 95% confidence interval (CI) for the presence of any of the conventional risk factors using multivariable logistic regression analyses. The models were adjusted for sex, age, smoking status, and log-transformed average daily steps. We also estimated the OR and 95% CI for the presence of any of the overall risk factors. Furthermore, we calculated the PAF due to these risk factors. The results showed that the prevalence of home hypertension was 39.0% (540/1384). The presence of any of the conventional risk factors, as well as any of the overall risk factors, was significantly associated with an increased prevalence of hypertension (OR 2.80, 95% CI 2.15–3.65; OR 2.50, 95% CI 1.93–3.22, respectively). The PAF for hypertension due to the presence of any of the conventional risk factors and the PAF due to the presence of any of the overall risk factors were 30.2% and 39.0%, respectively. In conclusion, the impact of the overall risk factors, including the urinary Na/K ratio and sleep efficiency, on home hypertension was higher than that of conventional risk factors alone. The management of the urinary Na/K ratio and sleep efficiency as well as conventional risk factors might be important in the management of blood pressure.
Inhibition of thrombin activity by a covalent-binding aptamer and reversal by the complementary strand antidote
Authors: Tabuchi Yudai , Yang Jay , Taki Masumi
Published: February 2021

We created a DNA-aptamer-type covalent drug where the pharmacological effect can be reversed by the complementary strand antidote.
Oxygen doping in antimony sulfide nanosheets to facilitate catalytic conversion of polysulfides for lithium–sulfur batteries
Authors: Zhang Yonggui , Yang Shuo , Zhou Suya , Zhang Libin , Gu Binbin , Dong Yangyang , Kong Suzhen , Cai Dong , Fang Guoyong , Nie Huagui , Yang Zhi
Published: February 2021

O-doped Sb2S3 nanosheets as a high-performance catalyst can effectively mitigate the shuttle effect, achieving outstanding electrochemical performance of lithium–sulfur batteries.
Covalent capture and electrochemical quantification of pathogenic E. coli
Authors: Klass Sarah H. , Sofen Laura E. , Hallberg Zachary F. , Fiala Tahoe A. , Ramsey Alexandra V. , Dolan Nicholas S. , Francis Matthew B. , Furst Ariel L.
Published: February 2021

Pathogenic E. coli pose a significant threat to public health by causing both foodborne illness and urinary tract infections. A sensitive electrochemical method to detect these pathogens can be used for surveillance and to prevent illness.
Multifunctional photoelectric sensors and catalysts for CO2RR and Cr(vi) solution based on a series of POM-based materials
Authors: Wang Chen , Ying Jun , Zhang Xin-yue , Zhang Bao-yue , Tian Ai-xiang , Wang Xiu-li
Published: February 2021

A series of POM-based materials can be used as photoelectric sensors and have high catalytic activities for CO2RR and the reduction of Cr(vi) solution, which are significant for environmental protection and energy shortage.
Ferrocene decorated unusual mercury(ii) dithiocarbamate coordination polymers: crystallographic and computational studies
Authors: Singh Amita , Singh Ayushi , Singh Suryabhan , Kociok-Köhn Gabriele , Muddassir Mohd. , Kumar Abhinav
Published: February 2021

Three new ferrocene decorated 1D coordination polymers of Hg(ii) dithiocarbamates were synthesized and the nature of their weak interactions was addressed using computational techniques.
Exploring organic semiconductors in solution: the effects of solvation, alkylization, and doping
Authors: Krumland Jannis , Valencia Ana Maria , Cocchi Caterina
Published: February 2021

We analyze the impact and the interplay of solvation, alkylization, and doping on the structural, electronic, and optical properties organic semiconductors modeled from first principles.
Probing BrCl from photodissociation of CH2BrCl and CHBr2Cl at 248 nm using cavity ring-down spectroscopy
Authors: Muthiah Balaganesh , Kasai Toshio , Lin King-Chuen
Published: February 2021

Investigation of molecular halogens as a primary product from the photodissociation of CH2BrCl and CHBr2Cl at 248 nm using cavity ringdown absorption spectroscopy (CRDS).
Controlling microgel deformation via deposition method and surface functionalization of solid supports
Authors: Hoppe Alvarez Laura , Rudov Andrey A. , Gumerov Rustam A. , Lenssen Pia , Simon Ulrich , Potemkin Igor I. , Wöll Dominik
Published: February 2021

The deformation of microgels deposited onto different substrates applying the three most common methods (spin-coating, drop-casting, and adsorption) was investigated by super-resolution fluorescence microscopy and molecular dynamics simulations.
Kinetic fall-off behavior for the Cl + Furan-2,5-dione (C4H2O3, maleic anhydride) reaction
Authors: Chattopadhyay Aparajeo , Gierczak Tomasz , Marshall Paul , Papadimitriou Vassileios C. , Burkholder James B.
Published: February 2021

Rate coefficients, k, for the gas-phase Cl + Furan-2,5-dione (C4H2O3, maleic anhydride) reaction were measured over the 15–500 torr (He and N2 bath gas) pressure range at temperatures between 283 and 323 K.
The role of site coordination on the CO2 electroreduction pathway on stepped and defective copper surfaces
Authors: Verga Lucas G. , Mendes Paulo C. D. , Ocampo-Restrepo Vivianne K. , Da Silva Juarez L. F.
Published: February 2021

Changes in adsorption site coordination on stepped and defective Cu surfaces affect reaction pathways and potential-determining steps for CO2 electroreduction.
A study on chemical exfoliation and structural and optical properties of two-dimensional layered titanium diselenide
Authors: Kumar Ashish , Sharma Rohit , Yadav Sandeep , Swami Sanjay Kumar , Kumari Reena , Singh V. N. , Ojha S. , Schneider Joerg J. , Srivastava Ritu , Sinha O. P.
Published: February 2021

Titanium diselenide (TiSe2) is the least studied member of the transition metal dichalcogenide family due to a lack of readily available synthesis methodology, controlled bandgap engineering, and rapid characterization of layers.
Synthesis of dense porous layered double hydroxides from struvite
Authors: Kwok W. L. Joyce , Suo Hongri , Chen Chunping , Leung D. W. Justin , Buffet Jean-Charles , O'Hare Dermot
Published: February 2021

An atom economic synthesis of dense porous layered double hydroxides (SLDHs) using an undesirable waste in wastewater treatment plants (struvite) is reported. The obtained SLDHs show high specific surface area, large pore volume and high density.
Eco-friendly and sustainable processing of wood-based materials
Authors: Akpan Emmanuel Isaac , Wetzel Bernd , Friedrich Klaus
Published: February 2021

Eco-friendly alternative processes are required for functionally modified wood to maintain low embodied energy and near zero emission levels.
Double emulsions with ultrathin shell by microfluidic step-emulsification
Authors: Ge Xinjin , Rubinstein Boris Y. , He Yifeng , Bruce Frederick N. O. , Li Liaonan , Leshansky Alexander M. , Li Zhenzhen
Published: February 2021

We present a simple microfluidic device based on tri-phasic co-flow step-emulsification, for high throughput production of double emulsions with an ultrathin shell in a single step.
Methylene- and thioether-linked cyanobiphenyl-based liquid crystal dimers CBnSCB exhibiting room temperature twist-bend nematic phases and glasses
Authors: Arakawa Yuki , Komatsu Kenta , Shiba Takuma , Tsuji Hideto
Published: February 2021

A homologous series of methylene- and thioether-linked cyanobiphenyl-based liquid crystal dimers, CBnSCB, was developed and found to exhibit stable twist-bend nematic (NTB) phases, which undergo vitrification to give NTBglass phases.
A light-fostered supercapacitor performance of multi-layered ReS2 grown on conducting substrates
Authors: Arya Nitika , Avasthi Piyush , Balakrishnan Viswanath
Published: February 2021

The light-fostered supercapacitor performance introduces a new realm in the field of smart energy storage applications.
Pillar[6]arene-based supramolecular polymeric materials constructed via electrostatic interactions for rapid and efficient organic dye removal from water
Authors: Yan Xin , Huang Youyou , Cen Moupan , Wang Jin , Shi Jian , Lu Bing , Wang Yang , Yao Yong
Published: February 2021

Pillar[6]arene-based polymeric materials were constructed from electrostatic interactions efficiently, and can further be applied in removing organic dyes from water.
Enhancement of the coordinating flexibility in a Schiff–Mannich combo ligand: forced generation of a new NiII–Ophenoxo–LnIII–Oalkoxo–LnIII array (Ln = Gd, Tb, Dy and Ho)
Authors: Bag Riya , Sikdar Yeasin , Saha Pinaki , Ghosh Prasanta , Drew Michael G. B. , Tang Jinkui , Goswami Sanchita
Published: February 2021

A series of 3d–4f complexes, containing rare NiLn2O4 topology, were synthesized by designing a new type of combo Schiff base–Mannich ligand.
Effect of the electronic structure on the robustness of ruthenium(ii) bis-phenanthroline compounds for photodissociation of the co-ligand: synthesis, structural characterization, and density functional theory study
Authors: Deshpande Megha S. , Morajkar Sudesh M. , Srinivasan Bikshandarkoil R. , Ahirwar Mini Bharati , Deshmukh Milind M.
Published: February 2021

Photodissociation of co-ligand in cis-[Ru(phen)2(L)2](PF6)2 (phen = 1,10-phenanthroline, L = isoquinoline 1; phthalazine 2), upon blue light irradiation was investigated via both experimental and DFT studies.
Co-cross-linked lanthanide-containing nanocomposite luminescent hydrogels
Authors: Dong Ningning , Song Zhihua , Zhu Tiyun , Qin Yan , Li Zhiqiang , Li Huanrong
Published: February 2021

We report a hydrogel with co-cross-linked networks synthesized via in situ polymerization of NIPA, LAPONITE® and lanthanide complex, endowing the hydrogel with thermoresponsive mechanical and luminescent performance.
Direct ink writing of recyclable and in situ repairable photothermal polyurethane for sustainable 3D printing development
Authors: Zheng Mingyue , Guo Qiuquan , Yin Xiangyu , Getangama Nuwansiri Nirosh , de Bruyn John R. , Xiao Junfeng , Bai Yang , Liu Mei , Yang Jun
Published: February 2021

Direct ink writing of disulfide-based composites offers a practical approach to customizable and straightforward sustainable 3D printing processes including recycling printing wastes, repairing damaged parts, and reducing processing defects.
Efficient transfection and long-term stability of rno-miRNA-26a-5p for osteogenic differentiation by large pore sized mesoporous silica nanoparticles
Authors: Hosseinpour Sepanta , Cao Yuxue , Liu Jingyu , Xu Chun , Walsh Laurence J.
Published: February 2021

Surface functionalized MSNs with large radial pores delivered miRNA-26a-5p into rat bone marrow mesenchymal stem cells and promote their osteogenic differentiation. Lyophilized dry powder formulation remained functional after 6 months of storage.
A mitochondria-targeted fluorescent dye naphthalimide-thioether-cyanine for NIR-activated photodynamic treatment of cancer cells
Authors: Shen Ronghua , Bai Jin , Qian Ying
Published: February 2021

The specific recognition of NPSCY towards Cys and the photodynamic treatment of cancer cells in this work.
The application of amide units in the construction of neutral functional dyes for mitochondrial staining
Authors: Ma Wei , Xu Bing , Sun Ru , Xu Yu-Jie , Ge Jian-Feng
Published: February 2021

To develop a new class of neutral fluorescent dyes with mitochondrial staining capacity, a series of functional dyes were obtained from Nile red (2a–e) and coumarin (3a–e) with different amide compounds via Suzuki coupling reactions.
Design and synthesis of low temperature printed metal oxide memristors
Authors: Carlos Emanuel , Deuermeier Jonas , Branquinho Rita , Gaspar Cristina , Martins Rodrigo , Kiazadeh Asal , Fortunato Elvira
Published: February 2021

Printed combustion-based aluminium oxide (AlOx) resistive switching devices produced at low temperature show a high reproducibility (95%) and multilevel cell operation with potential for hardware security applications.
Homoleptic cyclometalated dibenzothiophene–NHC–iridium(iii) complexes for efficient blue phosphorescent organic light-emitting diodes
Authors: Yun Bo-Sun , Kim So-Yoen , Kim Jin-Hyoung , Son Ho-Jin , Kang Sang Ook
Published: February 2021

Dibenzothiophene (DBT) and dibenzofuran (DBF) based NHC–Ir complexes lead to high-end deep-blue electroluminescence with unprecedented CIE coordinates of [0.14, 0.19] for m-IrSMe (EQEmax; 17.1%) and [0.14, 0.14] for m-IrOMe (EQEmax; 18.2%).
The role of fullerene derivatives in perovskite solar cells: electron transporting or electron extraction layers?
Authors: Fernandez-Delgado Olivia , Chandrasekhar P. S. , Cano-Sampaio Natalia , Simon Zoe C. , Puente-Santiago Alain R. , Liu Fang , Castro Edison , Echegoyen Luis
Published: February 2021

The role of fullerenes as interfacial electron extractors and as bulk electron transporters in PSCs was differentially assessed in order to optimize device performances.
Insight into intramolecular chemical structure modifications by on-surface reaction using photoemission tomography
Authors: Cojocariu Iulia , Feyersinger Florian , Puschnig Peter , Schio Luca , Floreano Luca , Feyer Vitaliy , Schneider Claus M.
Published: February 2021

We present the first evidence of an on-surface intramolecular reaction detected via an imaging method based on photoemission.
A facile synthetic protocol of α-Fe2O3@FeS2 nanocrystals for advanced electrochemical capacitors
Authors: Xia Qing , Xia Tong , Dai Meizhen , Wu Xiang , Zhao Yufeng
Published: February 2021

In this work, we report granular α-Fe2O3@FeS2 nanocrystals by a one-pot hydrothermal route. The as-obtained product as an electrode material shows excellent charge transfer ability and cyclic stability.
Polyoxometalate based ionic crystal: dual applications in selective colorimetric sensor for hydrated ZnCl2 and antimicrobial activity
Authors: Sabarinathan C. , Karthikeyan M. , Murugappan R. M. , Anthony Savarimuthu Philip , Shankar Bhaskaran , Parthasarathy Kannabiran , Arumuganathan T.
Published: February 2021

One-pot synthesis of POM-salt ([Himi]4[SiMo12O40] (1)) was achieved by mixing silicomolybdic acid and imidazole in acidic conditions and characterized by FTIR, TGA, SEM, EDX, ICP-OES and XPS.
The current state of methods for establishing reliability in qualitative chemistry education research articles
Authors: Watts Field M. , Finkenstaedt-Quinn Solaire A.
Published: February 2021

The tradition of qualitative research drives much of chemistry education research activity. When performing qualitative studies, researchers must demonstrate the trustworthiness of their analysis so researchers and practitioners consuming their work can understand if and how the presented research claims and conclusions might be transferable to their unique educational settings. There are a number of steps researchers can take to demonstrate the trustworthiness of their work, one of which is demonstrating and reporting evidence of reliability. The purpose of this methodological review is to investigate the methods researchers use to establish and report reliability for chemistry education research articles including a qualitative research component. Drawing from the literature on qualitative research methodology and content analysis, we describe the approaches for establishing the reliability of qualitative data analysis using various measures of inter-rater reliability and processes including negotiated agreement. We used this background literature to guide our review of research articles containing a qualitative component and published in Chemistry Education Research and Practice and the Journal of Chemical Education from the years 2010 through 2019 for whether they report evidence of reliability. We followed this by a more in-depth analysis of how articles from the years 2017 through 2019 discuss reliability. Our analysis indicates that, overall, researchers are presenting evidence of reliability in chemistry education research (CER) articles by reporting reliability measures, describing a process of negotiated agreement, or mentioning reliability and the steps taken to demonstrate it. However, there is a reliance on reporting only percent agreement, which is not considered an acceptable measure of reliability when used on its own. In addition, the descriptions of how reliability was established were not always clear, which may make it difficult for readers to evaluate the veracity of research findings. Our findings indicate that, as a field, CER researchers should be more cognizant of the appropriateness of how we establish reliability for qualitative analysis and should more clearly present the processes by which reliability was established in CER manuscripts.
Correction: A highly X-ray sensitive iridium prodrug for visualized tumor radiochemotherapy
Authors: Zhao Zhennan , Gao Pan , Ma Li , Chen Tianfeng
Published: February 2021

Correction for ’A highly X-ray sensitive iridium prodrug for visualized tumor radiochemotherapy’ by Zhennan Zhao et al., Chem. Sci., 2020, 11, 3780–3789, DOI: 10.1039/D0SC00862A
Potential origin of the state-dependent high-energy tail in the black hole microquasar Cygnus X-1 as seen with INTEGRAL
Authors: Cangemi F. , Beuchert T. , Siegert T. , Rodriguez J. , Grinberg V. , Belmont R. , Gouiffès C. , Kreykenbohm I. , Laurent P. , Pottschmidt K. , Wilms J.
Published: February 2021

Context. 0.1–10 MeV observations of the black hole microquasar Cygnus X-1 have shown the presence of a spectral feature in the form of a power law in addition to the standard black body (0.1–10 keV) and Comptonization (10–200 keV) components observed by INTEGRAL in several black-hole X-ray binaries. This so-called “high-energy tail” was recently shown to be strong in the hard spectral state of Cygnus X-1, and, in this system, has been interpreted as the high-energy part of the emission from a compact jet.

Aims. This result was nevertheless obtained from a data set largely dominated by hard state observations. In the soft state, only upper limits on the presence and hence the potential parameters of a high-energy tail could be derived. Using an extended data set, we aim to obtain better constraints on the properties of this spectral component in both states.

Methods. We make use of data obtained from about 15 years of observations with the INTEGRAL satellite. The data set is separated into the different states and we analyze stacked state-resolved spectra obtained from the X-ray monitors, the gamma-ray imager, and the gamma-ray spectrometer (SPI) onboard.

Results. A high-energy component is detected in both states, confirming its earlier detection in the hard state and its suspected presence in the soft state with INTEGRAL, as seen in a much smaller SPI data set. We first characterize the high-energy tail components in the two states through a model-independent, phenomenological analysis. We then apply physical models based on hybrid Comptonization (eqpair and belm). The spectra are well modeled in all cases, with a similar goodness of the fits. While in the semi-phenomenological approach the high-energy tail has similar indices in both states, the fits with the physical models seem to indicate slightly different properties. Based on this approach, we discuss the potential origins of the high-energy components in both the soft and hard states, and favor an interpretation where the high-energy component is due to a compact jet in the hard state and hybrid Comptonization in either a magnetized or nonmagnetized corona in the soft state.
Study on flow noise characteristics of Bionic cylinder based on acoustic analogy
Authors: Cui Zixian , Song Hao , Li Qi , An Buchao , Su Lin
Published: February 2021

The drag and noise reduction of the flow around a cylinder is one of the important topics in hydrodynamics and acoustics. In this paper, three typical bionic cylinders are designed based on the serrated structure on the surface of shark skin. Using Large eddy turbulence model and Lighthill’s acoustic analogy method, the flow noise characteristics of smooth cylinder and three kinds of bionic cylinders at different Reynolds numbers were compared, and the structure of cylinder surface was optimized. The results show that the main source of the flow noise around a cylinder is dipole noise, which is caused by the periodic fluctuating pressure on the cylinder surface.The bionic cylinder can reduce the amplitude of the fluctuating pressure, improve the wake flow field and reduce the wake vorticity, so as to reduce the noise. Among the three kinds of bionic cylinder, V-shaped bionic cylinder has the best noise reduction effect, and the critical value of S/H of V-shaped cylinder is about 2.5. When s / h > 2.5, V-shaped bionic cylinder has no effect of noise reduction.
Sound source location for low-altitude aircraft based on sub-band extraction
Authors: Zhu Junwen , Cheng Ruixia , Li Jiawei , Tian Yu , Zhang Yiwen
Published: February 2021

The acoustic signal of low-altitude aircraft shows regular distribution in frequency and has obvious harmonic crest of both fundamental frequency and double frequency.Therefore, this paper presents a low complexity algorithm of acoustic location based on feature sub-band extraction for low-altitude aircraft. The algorithm firstly searches the eigenfrequency points which occupy the main energy in the sound signal. Then the cost function is constructed based on the MUSIC method by the sub-band corresponding to the eigenfrequency point. Finally, the amplitude is weighted by the maximum ratio combination principle to obtain the spectral function of array space, by which DOA estimation is realized for the spatial spectrum. Simulation results show that the algorithm is less complex than traditional wide-band DOA algorithm, and its main lobe is easier to recognize and has better spatial resolution.
A design of lens antenna with high gain
Authors: Gao Darong
Published: February 2021

In this paper, A lens antenna with high gain is proposed. The antenna is composed of the microstrip antenna and the hemisphere dielectric lens, and the lens is loaded on the top. The polyethylene is used to fabricated the hemisphere dielectric lens. The antenna has dimensions of 47.58 mm × 47.58 mm × 24.79 mm, which is corresponding to the electrical size of 1.586λ0×1.586λ0×0.826λ0, where λ0 is the free-space wavelength at 10GHz. The impedance bandwidth (return loss<-10dB) is 12.7%(9.24 GHz-10.51 GHz), and the peak gain is 9.06 dBi. The hemisphere dielectric lens can improve the gain of the microstrip antenna. The proposed lens antenna is suitable for wireless communications systems.
Research on improving measurement accuracy of acoustic transfer function of underwater vehicle
Authors: Li Jiangqiao , Jiang Li , Yu Fujian , Zhang Ye , Gao Kun
Published: February 2021

To address the problem that acoustic transfer functions with underwater platforms cannot be measured accurately, this paper presents a method based on phase compensation to improve the accuracy of acoustic transfer function measurements on underwater platforms. The time-domain impulse response signals with multiple cycles are first collected and intercepted, and then their phase differences are estimated using the least-squares method, and phase compensation is used to align the phases of all the signals, and then the impulse response signals are weighted and averaged over all the impulse response signals to cancel out the random noise. The water pool test proves that this method reduces the measurement random noise while obtaining a high-fidelity time domain transfer function, which effectively improves the signal-to-noise ratio of the measurement. The method adopts only one measurement signal, and without changing the measurement system, the random noise is cancelled out by the in-phase superposition of the multi-cycle impulse response signals to avoid the nonlinear distortion of the measurement results.
Research on the combination of improved Sobel operator and ant colony algorithm for defect detection
Authors: Zhou Yilu , Fu Xiaojin
Published: February 2021

There are many aspects in the defect detection system. Any deviation in any link will affect the accuracy of the final detection, and edge detection is very important in the image preprocessing stage. In this paper, a new edge detection algorithm is proposed. Firstly, the improved Sobel operator is used to detect the image contour, and then the position of the contour is taken as the initial position of ant colony algorithm. The experimental results show that the algorithm can extract the contour with uniform thickness and length from the original image collected by the industrial camera, and the running time of the algorithm is almost the same as that of the traditional ant colony algorithm, thus providing more accurate data for the defect detection of products in the later stage.
Technical study for complete one-time sealing of vacuum interrupter
Authors: Xue Congjun , Li Xiaozhao , Liu Shibai , Zhao Fangshuai
Published: February 2021

This paper briefly describes the development process of sealing technology for vacuum interrupter, analyze the main characteristics of each stage and difficulties in realizing one-time sealing. Five design schemes are put forward to achieve complete one-time sealing, and the vacuum brazing tests were carried out according to the scheme. The test samples were dissected and analyzed, This article it contrastive analysis. The contact structure was chosen as the best structure for a complete one-time sealing, and made into a vacuum interrupter. The vacuum interrupter has passed the vacuum, the contact resistance, the power-frequency voltage-withstand test, BIL and the breaking test. It is proved that the one-time sealing of this structure can meet the requirements.
Performance analysis of low-speed and large-thrust cylindrical linear motor with double-layer fractional-slot winding
Authors: Yang Qifan , Liu Xiaoke , Yang Yue , Cao Rong , Hao Wenbo , Xu Mingyu , Zhou Feng
Published: February 2021

For low-speed and large-thrust situations, the single-layer winding permanent magnet linear motor is inefficient because of its large distance, and the thrust fluctuation is large. In order to solve this problem, a finite element analysis model of cylindrical permanent magnet linear motor is established in a cylindrical permanent magnet linear motor, and the Ansoft software simulation is used to ensure the positioning force and thrust of the double-layer winding motor and single-layer winding motor under the same key parameters. The performance of double-layer winding motor and Single-layer winding motor at different frequencies is compared and analyzed. The simulation results show that the cylindrical linear motor with double-layer fractional-slot winding structure is more suitable for occasions with low speed and large thrust, and has higher operation efficiency.
Design of multi-channel analog acquisition system based on DSP + FPGA architecture
Authors: Zhang Yi , Wang Yanyong , Jiang Zhe , Jiang Yutong , Zhang Xiaozheng
Published: February 2021

This paper proposes a design and implementation of a general multi-channel analog acquisition system based on DSP + FPGA architecture. In terms of hardware architecture, FPGA is used to achieve high-speed and high reliability switching between different analog channels; FPGA + DSP data processing architecture is used to separate data acquisition and algorithm processing.
An algorithm for extracting groove rail area based on improved Hough transform
Authors: Fang Zhongbin , Huang Xiaojie , Ye Kangquan , Ji Jing , Wu Qiantong , Ma Xizhe , Xie Yongjun
Published: February 2021

In order to improve the accuracy and real-time performance of the automatic cleaning of groove rails in modern trams, this paper proposes a groove rail region extraction algorithm based on improved Hough transform. First, in order to speed up the detection and remove noise, the algorithm performs a series of pre-processing on the images collected by the camera, and then use the Canny edge detection method to extract the edge feature information of the groove rail. Finally, the algorithm is improved on the basis of the traditional Hough transform method according to the actual environment. The algorithm proposes three constraints from the straight line length, the slope of the straight line and the distance between the left and right edges, making the algorithm more feasible and accurate in extracting groove rail area. The extraction accuracy reached 97.9%, and the average extraction speed was 0.1903s, laying the foundation for the automatic cleaning of trough rails of modern trams.
Research on application method of uncertainty quantification technology in equipment test identification
Authors: Wang Jiajia , Chen Hao , Ma Jing , Zhang Tong
Published: February 2021

This paper introduces the concepts of equipment test qualification and uncertainty quantification, and the analysis framework and process of equipment test uncertainty quantification. It analyzes the data uncertainty, model uncertainty and environmental uncertainty, and studies the corresponding uncertainty quantification theory to provide technical reference for the application of uncertainty quantification technology in the field of test identification.
Research on cloud computing high-density data center infrastructure and environment matching technology
Authors: Shen Lianteng , Qian Shengpan , Zhai Tianyi , Li Ling , Li Zhe
Published: February 2021

The current rapid development of cloud computing and networks has put forward new requirements for the construction of new infrastructure such as data centers. This paper compares traditional data centers and high-density data centers, proposes a three-tier infrastructure for high-density data centers, and analyzes the data center environment. To solve the obvious problem of software and hardware heterogeneity in high-density data centers, this paper uses virtualization technology to pool resources in high-density data centers and introduces SOA architecture to manage software and hardware resources hierarchically. Finally, the data center infrastructure and environment matching technology are studied.
Design of control system and motion analysis of vision capture for small hexapod robot
Authors: Jin Yingzi , Li Dahong , Qian Feng , Wang Binrui
Published: February 2021

Aiming at the difficulties in motion control and performance analysis of hexapod robot, stm32 embedded processor is used to drive the 18-channel steering gear control board to control the robot's motion. CAM Shift algorithm is designed to track the centroid target of the moving robot and calculate the motion speed. The gait experiment and performance analysis of straight line and steering were carried out on the self-developed prototype. The results show that the design integrates the machine vision tracking technology and the motion control technology of the hexapod robot, which can realize the control and motion analysis functions.
Design of emergency UAV network identity authentication protocol based on Beidou
Authors: Zhao Donghao , Lu Yu , Liu Xiaoguang , Qiao Wenxin , Li Zhiwei , Liu Yicen
Published: February 2021

In view of the bad environment and intermittent communication of UAV network, based on the short message communication function of Beidou satellite navigation system, which can provide all-weather and no blind area communication service, a UAV network identity authentication protocol under emergency state when conventional means cannot communicate is designed.
A novel hybrid IWO and CS algorithm for phase-only pattern synthesis of large array antenna
Authors: Liu Chao , Yang Bo , Li Chuan
Published: February 2021

In this paper, a novel hybrid Invasive Weed Optimization (IWO) and Cuckoo Search (CS) algorithm (IWO/CS) is presented for phase-only pattern synthesis of large array antenna. The hybrid IWO/CS algorithm embeds the Levy flight of CS algorithm into IWO algorithm as a global guide, thereby enhancing the global search ability of the algorithm. At the same time, in order to avoid trapping into the local optimal solution, mutation operator is introduced to enhance search ability of the algorithm. Finally, competitive exclusion operation is improved to maintain the diversity of population. The hybrid algorithm is applied to phase-only beam shaping to achieve main lobe broadening and side lobe depression. Simulation results demonstrate the superiority of the hybrid IWO and CS algorithm.
A new blind separation method for under-determined speech signals based on single source interval pre-extraction
Authors: Hao Xiangning , Zhang Guixin , Deng Liqiong
Published: February 2021

A new method is proposed to realize the blind separation of speech signals under underdetermined conditions. Before estimating the mixed parameters, the single-source interval pre-extraction operation first "filters" out a part which is obviously not a single source. The time-frequency interval of the source analysis domain category.The simulation results show the good performance of the algorithm.
Optical service unit (OSU)-based next generation optical transport network (NG OTN) technology and verification
Authors: Bai Lirong
Published: February 2021

With the development of transmission technologies, optical transport network (OTN) has evolved from a digital encapsulation technology to a network technology that supports multi-service transport. As the OTN gradually expands to the edge of the metropolitan area network (MAN) and enterprise users have higher quality requirements on bandwidth and service security, more and more private line services are provided via OTN network. Therefore, the OTN container is transformed from an optical data unit (ODU) to an optical service unit (OSU). The OTN industry has studied several OSU technologies to fit the development trends of NG OTN, aiming at transporting 2 Mbit/s to 100 Gbit/s constant bit rate (CBR) services and Ethernet services with high efficiency and more flexibilities, as well as reducing OTN network deployment and operation and maintenance (O&M) costs. In this work, several key technologies in NG OTN are introduced including NG OTN technical architecture, OSU frame format, client mapping and OSU multiplexing. Based on these technologies, we (China Mobile) took the lead in conducting the industry's first NG OTN test in Qingdao, which verified the service transport capability and lower latency performance of OSUs and promoted the maturity of the NG OTN industry chain.
Back-end porting of FT_MX based on LLVM compilation architecture
Authors: Deng Ping , Zhu Xiaolong , Sun Haiyan , Ren Yi
Published: February 2021

The processor FT_MX is a high-performance chip independently developed by the National University of Defense Technology, with an innovative architecture and instruction set. LLVM architecture is a widely used and efficient open source compiler framework initiated by the University of Illinois. This paper introduces the basic architecture and functions of LLVM, analyzes the back-end migration mechanism of the architecture in detail, and gives the specific process of implementing FT_MX back-end migration, and realizes the support of LLVM architecture to the back-end of FT_MX processor.
Design and research of hybrid cloud desktop scheme in colleges and universities
Authors: Xiong Nian , Zhou Shan , Wu Zujian , Zhang Zhen
Published: February 2021

This paper analyzes and compares the four mainstream cloud desktop technologies: RDS, VDI, IDV and VOI. According to the practical application in colleges and universities, a hybrid cloud desktop technology scheme is designed and proposed, and the specific implementation method of the integration of VDI and VOI is studied. In view of the particularity and requirements of experimental courses and application scenarios, an application model based on this technical scheme is designed, which is suitable for all the common scenes of computer experimental teaching, realizes the deep integration of cloud desktop and teaching activities, and also provides reference for the construction and application of cloud desktop technology in colleges and universities.
A novel interestingness measure based on fusion model for association rules mining
Authors: Yang Junrui , Xu Lin
Published: February 2021

Aiming at the shortcomings of the traditional "support-confidence" association rules mining framework and the problems of mining negative association rules, the concept of interestingness measure is introduced. Analyzed the advantages and disadvantages of some commonly used interestingness measures at present, and combined the cosine measure on the basis of the interestingness measure model based on the difference idea, and proposed a new interestingness measure model. The interestingness measure can effectively express the relationship between the antecedent and the subsequent part of the rule. According to this model, an association rules mining algorithm based on the interestingness measure fusion model is proposed to improve the accuracy of mining. Experiments show that the algorithm has better performance and can effectively help mining positive and negative association rules.
Study on the application of LSTM-LightGBM Model in stock rise and fall prediction
Authors: Guo Yuankai , Li Yangyang , Xu Yuan
Published: February 2021

This paper proposes a hybrid financial time series forecast model based on LSTM and LightGBM, namely LSTM_LightGBM model. Use the LightGBM model to train the processed stock historical data set, and save the training results. Then the opening price, closing price, highest price, lowest price, trading volume and adjusted closing price are separately input into the LSTM model for prediction. The prediction result of each attribute is used as the test set of the prediction after LightGBM training. Constantly adjust the parameters of each model, and finally get the optimal stock price forecast model. The model is validated with the rise and fall of AAPL stock. Through the comparison of evaluation index root mean square error RMSE, mean absolute error MAE, prediction accuracy Accuracy and f1_score. It is found that the LSTM_LightGBM model exhibits stable and better prediction performance in the stock prediction. That is to say, the LSTM_LightGBM model proposed in this paper is stable and feasible in the stock price fluctuation forecast.
Cloud computing based big data platform construction of university informatization teaching service in Yunnan Province under the background of community of destiny
Authors: Chen Jianbing , Xu Bo , Tang Wei , Zou Wei , Yang Weiguo , Liang Li , Zhan Zhenyu , Tang Mingjing , Bai Fengxiang , Chen Yanchun , Yang Deqiang , Chen Bin , Lin Jie
Published: February 2021

This paper summarizes the current situation of the university education informatization, cloud computing and the application of big data in education, and preliminarily constructs the big data platform model of university informatization intelligent teaching service of Yunnan University Teacher Education Alliance Based on cloud computing Part of the content of the model is described to provide reference for regional alliance education related research.
The interconnection exchange and complex systems properties in power grid network
Authors: Hadaj Piotr , Nowak Marek , Strzałka Dominik
Published: February 2021

A case study based on the real data obtained from the Polish PSE System Operator of the highest voltages electrical energy network is shown. The data about the interconnection exchange and some complex networks (graphs) parameters were examined, after the removal of selected nodes. This allowed to test selected network parameters and to show that the breakdown of only three nodes in this network can cause significant drop of its average efficiency.
Design of intelligent integrated monitoring system under multistation fusion platform
Authors: Shen Lianteng , Li Ling , Li Zhe , Zhang Xin , Ma Junjie
Published: February 2021

With the continuous advancement of the national energy strategy of China, constructing multistation fusion platform (MSFP) of substations, energy storage stations, and data center stations by taking advantage of the remaining resources of substations is a development trend. The monitoring of equipment operation and environmental parameters is a powerful guarantee for the stable and reliable operation of MSFP. Thus, this study developed an intelligent integrated monitoring system construction method that consists of state perception, information fusion, and decision and control layers. First, the state of equipment and environmental parameters were monitored efficiently through built-in status signals and multisensing techniques. Then, the multilevel transmission network, composite data structure, and data interface are integrated to achieve the collection of multisite information. Moreover, the device object model and station-level digital model were designed. Finally, the abnormal fault diagnosis of equipment, data fusion regulation, and coordinated optimization control were completed by using knowledge graph, data optimization and neural network modeling, and hierarchical analysis of multiple application scenarios in MSFP. The intelligent monitoring system can monitor and control the equipment, operation, and environment in the MSFP efficiently, thereby providing technical support for the new development of China’s electric power industry.