bluuebunny/crossref_metadata_2025 huggingface dataset:
Freshwater Seepage Into Sediments of the Shelf, Shelf Edge, and Continental Slope of the Canadian Beaufort Sea
Authors: Gwiazda R. , Paull C. K. , Dallimore S. R. , Melling H. , Jin Y. K. , Hong J. K. , Riedel M. , Lundsten E. , Anderson K. , Conway K.
Published: August 2018

Long‐term warming of the continental shelf of the Canadian Beaufort Sea caused by the transgression associated with the last deglaciation may be causing decomposition of relict offshore subsea permafrost and gas hydrates. To evaluate this possibility, pore waters from 118 sediment cores up to 7.3‐m long were taken on the shelf and slope and analyzed for chloride concentrations and δ180 and δD composition. We observed downcore decreases in pore waters Cl− concentration in sediments from all sites from the inner shelf (<20‐m water depth), from the shelf edge, from the outer slope (down to 1,000‐m water depths), and from localized shelf features such as midshelf pingo‐like features and inner shelf pockmarks. In contrast, pore water freshening is absent from all investigated cores of the Mackenzie Trough. Downcore pore waters Cl− concentration decreases indicate regional widespread freshwater seepage. Extrapolations to zero Cl− of pore water Cl− versus δ180 regression lines indicate that freshwaters in these environments carry different isotope signatures and thus are sourced from different reservoirs. These isotopic signatures indicate that freshening of shelf sediments pore waters is a result of downward infiltration of Mackenzie River water, freshening of shelf edge sediments is due to relict submarine permafrost degradation or gas hydrate decomposition under the shelf, and freshening of slope sediments is consistent with regional groundwater flow and submarine groundwater discharge as far as 150 km from shore. These results confirm ongoing decomposition of offshore permafrost and suggest extensive current groundwater discharge far from the coast.
Speleothems as Magnetic Archives: Paleosecular Variation and a Relative Paleointensity Record From a Portuguese Speleothem
Authors: Ponte J. M. , Font E. , Veiga‐Pires C. , Hillaire‐Marcel C.
Published: August 2018

We provide a high‐resolution and complete paleomagnetic study from a middle‐Holocene (~4,100–3,300 years Before Common Era, BCE) dome‐shaped speleothem (SPAIV) from Algarve, Portugal. Our results show that the SPAIV speleothem carries a primary and stable remanent magnetization, for which directions are similar to other speleothems from the western Alps. Magnetic declination and inclination curves are also comparable to current paleosecular variation models (SHA.DIF.14k, CALS10k.1b, and pfm9k.1a), one of them (SHA.DIF.14k) fitting better with the present data set. Relative paleointensity was estimated using two different methods: conventional normalization of natural remanent magnetization by anhysteretic and isothermal, and the pseudo‐Thellier method, which is being tested here for the first time in a speleothem. Both methods show similar results, with a minimum intensity peak at ~3,850 years BCE. This low relative intensity is observed in all samples pertaining to the same respective calcite laminae. These results suggest that high growth rate speleothems are good high‐resolution recorders of the direction and intensity of the Earth's magnetic field.
Chemical Variations in the 1998, 2011, and 2015 Lava Flows From Axial Seamount, Juan de Fuca Ridge: Cooling During Ascent, Lateral Transport, and Flow
Authors: Clague David A. , Paduan Jennifer B. , Dreyer Brian M. , Chadwick William W. , Rubin Kenneth R. , Perfit Michael R. , Fundis Allison T.
Published: August 2018

Lava flows erupted at Axial Seamount in 1998, 2011, and 2015 are chemically heterogeneous and display decreases in MgO content in their glass rinds with increasing distance from the summit. The trends are consistent with eruption temperature decreases down the rift zones of ~0.5 °C/km within 20 km of the caldera and ~0.9 °C/km at greater distance (only observed in the 2011 eruption). Cooling during magma transport in dikes is the likely cause of the temperature trends observed, related to the effects of cooler wall rocks in areas with less frequent dike intrusions. Flows also cooled as they advanced on the seafloor at rates 3–5 times greater than observed at Kilauea volcano in Hawaii for subaerial tube‐fed pahoehoe flows. Lavas erupted in and near the caldera in 1998 and 2011 are slightly enriched transitional mid‐ocean ridge basalt that are aphyric and have glass MgO content of 7.1–7.6 wt %. The 2015 lavas have similarly enriched incompatible element compositions typical of transitional mid‐ocean ridge basalt, but those erupted inside and on the northeast rim of the caldera contain higher glass MgO of 7.8–8.3 wt % and more abundant plagioclase phenocrysts typical of the normal mid‐ocean ridge basaltic lavas erupted between 1290 and 1370 CE. The brief recharge period between the 2011 and 2015 eruptions did not allow magma stored in the shallow reservoir to cool and degas as much as between prior eruptions since 1650 CE, suggesting that the most recent recharge period was shorter than the multicentennial average.
Using Isotopic and Geochemical Tracers to Determine the Contribution of Glacier‐Snow Meltwater to Streamflow in a Partly Glacierized Alpine‐Gorge Catchment in Northeastern Qinghai‐Tibet Plateau
Authors: Chang Qixin , Ma Rui , Sun Ziyong , Zhou Aiguo , Hu Yalu , Liu Yanguang
Published: August 2018

Compared with arctic and subarctic catchments, our knowledge about the hydrological functions of glaciers and porous aquifers is still limited for the partly glacierized alpine‐gorge headwaters in the Qinghai‐Tibet Plateau. Here we examine the impact of glacial and groundwater storage on the variability of warm‐season (June to September) discharge from the Hulugou catchment, an alpine‐gorge headwater with 3% glacial coverage, by quantifying the timing and magnitude of contributions of glacier‐snow meltwater, baseflow, and rainwater to streamflow using a three‐component hydrograph separation model. It is found that baseflow was the largest component (55 ± 2%) of warm‐season streamflow while glacier‐snow meltwater also contributed significantly (30 ± 10%) despite of the very low glacial coverage. We suggest that the water flowing out of glaciers was mainly supplied by the melting short‐ and intermediate‐term storages (i.e., snow over glaciers), which led to the high meltwater contribution to streams during the warm season and the high peaks of meltwater discharge following heavy precipitation events. The porous aquifers in piedmont plain may serve as major reservoirs that store a growing body of groundwater during the warm season, which explains the general increasing trend of baseflow contribution during this period. The moraine and talus deposits in high mountains, by contrast, allow groundwater to pass through them quickly and therefore being responsible for the obvious responses of baseflow contribution amount to heavy rainfall events. Our findings suggest that small mountain glaciers and porous aquifers may play a greater role than expected in hydrological regulation in the alpine‐gorge catchments of northeastern Qinghai‐Tibet Plateau.
Improving Short‐Term Rainfall Forecasts by Assimilating Weather Radar Reflectivity Using Additive Ensemble Perturbations
Authors: Yokota S. , Seko H. , Kunii M. , Yamauchi H. , Sato E.
Published: August 2018

To improve short‐term rainfall forecasts through direct assimilation of radar reflectivity, atmospheric variables associated with rainfall should be modified based on their correlation with reflectivity. However, it is difficult to estimate such correlations. The ensemble Kalman filter can estimate the correlation by means of ensemble forecasts, although the estimation is limited to when rainfall is forecast by at least one member at analysis points. To assimilate reflectivity effectively even at points at which no rainfall is forecast, we suggest adding ensemble reflectivity perturbations, which are correlated with atmospheric variables, before ensemble Kalman filter assimilation. In the present study, this correlation is calculated in the whole computational domain including the rainfall regions. We apply this procedure to assimilation experiments with 1‐km horizontal grid interval for two tornadic supercells that occurred on 6 May 2012 and on 2 September 2013, and we succeed in improving short‐term rainfall forecasts by modifying wind, temperature, and water vapor.
Validation of SABER v2.0 Operational Temperature Data With Ground‐Based Lidars in the Mesosphere‐Lower Thermosphere Region (75–105 km)
Authors: Dawkins E. C. M. , Feofilov A. , Rezac L. , Kutepov A. A. , Janches D. , Höffner J. , Chu X. , Lu X. , Mlynczak M. G. , Russell J.
Published: August 2018

The National Aeronautics and Space Administration (NASA) Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) Sounding of the Atmosphere using Broadband Radiometry (SABER) instrument performs near‐global measurements of the vertical kinetic temperature (Tk) profiles and volume mixing ratios of various trace species (including O3, CO2, and H2O), with data available from 2002 to present. In this work, the first comparative study of the latest publically available SABER version 2.0 operational retrieval is reported in order to assess the performance of satellite Tk profiles relative to high‐resolution ground‐based lidar profiles. Collocated multiyear seasonal average Tk profiles were compared at nine different locations, representing a variety of different latitudes. In general, the SABER v2.0 and lidar mean seasonal Tk profiles agree well, with the smallest absolute values of ΔTk (z) (SABER minus lidar) found between 85 and 95 km, where the respective SABER and lidar uncertainties were smallest. At altitudes ≥100 km, the SABER Tk (z) typically exhibited warmer temperatures relative to the lidar Tk (z) profiles, whereas for altitudes ≤85 km, SABER Tk (z) was cooler. Relative to lidar, SABER tends to exhibit a warm bias during high‐latitude summertime, with the reasons for this currently still unclear. Overall, SABER was able to reproduce the general latitude‐ and season‐specific variations in the lidar Tk profiles and shown to be statistically similar for most seasons, at most locations, for the majority of altitudes, and with no overall bias.
On the Upward Extension of the Polar Vortices Into the Mesosphere
Authors: Harvey V. Lynn , Randall Cora E. , Goncharenko Larisa , Becker Erich , France Jeff
Published: August 2018

The polar vortices play a central role in vertically coupling the atmosphere from the ground to geospace by shaping the background wind field through which atmospheric waves propagate. This work extends the vertical range of previous polar vortex climatologies into the upper mesosphere. The mesospheric polar vortices are defined using the CO gradient method with Microwave Limb Sounder satellite data; the stratospheric polar vortices are defined using a stream function‐based algorithm with data from meteorological reanalyses. Strengths and weaknesses of the two vortex definitions are given, as well as recommendations for when, where, and why to use each definition. Midwinter mean vortex geometry in the mesosphere is funnel shaped in the Arctic, with a wide top and narrow bottom. The Antarctic mesospheric vortex tapers with height in early winter and broadens with height in late winter. The seasonal evolution of mesospheric vortex frequency of occurrence, size, and zonal symmetry in both hemispheres is presented. Unexpected behavior above 60 km includes late season vortex broadening in both hemispheres, especially following winters without sudden stratospheric warmings. Following extreme stratospheric disturbances the polar night jet in the mesosphere strengthens and shifts poleward, resulting in a mesospheric vortex that contracts. Overall, the mesospheric polar vortices are more similar between the two hemispheres than their stratospheric counterparts. The vortex climatology presented here serves as an observational benchmark to which the mesospheric polar vortices in high‐top climate models can be evaluated.
Radiation Effects on Satellites During Extreme Space Weather Events
Authors: Hands A. D. P. , Ryden K. A. , Meredith N. P. , Glauert S. A. , Horne R. B.
Published: August 2018

High‐energy trapped electrons in the Van Allen belts pose a threat to the survivability of orbiting spacecraft. Two key radiation effects are total ionizing dose and displacement damage dose in components and materials, both of which cause cumulative and largely irreversible damage. During an extreme space weather event, trapped electron fluxes in the Van Allen belts can increase by several orders of magnitude in intensity, leading to an enhanced risk of satellite failure. We use extreme environments generated by modeling and statistical analyses to estimate the consequences for satellites in terms of the radiation effects described above. A worst‐case event could lead to significant losses in power generating capability—up to almost 8%—and cause up to four years' worth of ionizing dose degradation, leading to component damage and a life‐shortening effect on satellites. The consequences of such losses are hugely significant given our increasing reliance on satellites for a vast array of services, including communication, navigation, defense, and critical infrastructure.
Fluid Flow, Brecciation, and Shear Heating on Faults: Insights From Carbonate Clumped‐Isotope Thermometry
Authors: Swanson E. M. , Wernicke B. P. , Eiler J. M.
Published: August 2018

Slip on gently dipping detachments in the brittle crust has been enigmatic for decades, because fracture mechanics laws predict frictional resistance is too great for sliding to occur, except under rather unusual circumstances. The Miocene Mormon Peak detachment in Nevada and the Eocene Heart Mountain detachment in Wyoming are two well‐studied examples of upper crustal, carbonate‐hosted low‐angle detachments, with highly debated slip processes. Both low‐angle faults were active during regional magmatism, and a number of proposed slip mechanisms involve magmatic fluids, frictional heating, or both. To address the role that magmatic fluids and frictional heating may have played in reducing friction, we measured clumped‐isotope ratios on 137 carbonate samples from these faults. The majority of fault breccias and gouges on the detachment slip surface record temperatures that are colder than the host rock. Surprisingly, samples from within 5 m of the Heart Mountain detachment average just 65 °C, and not a single sample (out of 37 measurements, excluding metamorphosed host rock at White Mountain) records a temperature greater than 90 °C. Along both faults, most samples are depleted in δ18O relative to the host rock, indicating that meteoric, not magmatic, fluids were present and interacting with the fault rock. However, a few samples preserve temperatures of over 160 °C, which, based on textural and geochemical criteria, are difficult to explain other than by frictional heating during slip. These temperatures are recorded in one sample directly on the Mormon Peak detachment slip surface and in two hanging wall localities above the Heart Mountain detachment.
Synchronous Seafloor Spreading and Subduction at the Paleo‐Convergent Margin of Semail and Arabia
Authors: Boudier Françoise , Nicolas Adolphe
Published: August 2018

The Semail ophiolite is the largest and best‐exposed ophiolite, having preserved intact record of a precollision system related to Neotethyan Ocean closure. Breaking with the alternative models of ophiolite exhumation and emplacement, this paper builds on integrating the joined contribution of tectonic evolution of the continental margin in the premise of the ophiolite obduction. Connecting the along‐strike segmentation of the ophiolite recorded in the lithospheric flow structure, and recent high‐precision dating, results in a 3‐D model of evolution of the ophiolite and its continental margin during Jurassic‐Cretaceous time. Among the relevant characteristics newly accounted, (1) the contamination of the ophiolite by fluids and magmas of continental origin; (2) the discrimination of different types of metamorphics associated to the ophiolite, and conventionally classified metamorphic soles; (3) the instability of the Arabian margin during the Late Jurassic‐Cretaceous times; (4) the new precise ages relating to overlapping of spreading and detachment; and (5) the inferred vergence of Neotethyan closure during late Mesozoic are stressed. The complex stem revealed may relate to processes associated with spreading center subduction at ridge‐trench‐transform (RTT) triple junction, as documented along a convergent margin. The Semail ophiolite emplacement on the Arabia continental margin would result from a temporary Arabian platform‐directed subduction zone that consumed the southern Tethyan plate during Late Jurassic‐Cretaceous time.
Electrochemical formation of molybdenum phosphate on a pencil graphite electrode and its potential application for the detection of phosphate ions
Authors: Arvas Melih Besir , Gürsu Hürmüs , Gençten Metin , Sahin Yucel
Published: August 2018

One-step electrochemical preparation of molybdenum phosphate coated pencil graphite electrode was achieved in phosphoric acid and lithium molybdate solutions at room temperature.
A novel method to synthesize stable nitrogen-rich polynitrobenzenes with π-stacking for high-energy-density energetic materials
Authors: Yang Xiaoming , Lin Xinyu , Yang Li , Zhang Tonglai
Published: August 2018

A larger multi-nitro, multi-azide and multi-oxidized furazan ring compound with π–π stacking is herein reported. The coupling reaction of a NN bond and an azido was an efficient method to synthesize benzotriazole.
A novel mass spectrometry method based on competitive non-covalent interaction for the detection of biomarkers
Authors: Han Jing , Li Yafeng , Zhan Lingpeng , Xue Jinjuan , Sun Jie , Xiong Caiqiao , Nie Zongxiu
Published: August 2018

We report a novel MS platform based on competitive non-covalent interaction between ssDNA and a competitive mass tag towards AuNPs for the detection of biomarkers, which could be applicable to the sensitive analysis of clinical samples.
Boosting the electrochemical water oxidation reaction of hierarchical nanoarrays through NiFe-oxides/Ag heterointerfaces
Authors: Zhu Bin , Hu Qi , Liu Xiufang , Li Guomin , Fan Liangdong , Zhang Qianling , Liu Jianhong , He Chuanxin
Published: August 2018

The heterointerfaces between metallic Ag and NiFe-oxides on hierarchical arrays are found to possess high activity for the alkaline oxygen evolution reaction.
Catalytic polymerization of naphthalene by HF/BF3 super acid: an ab initio density functional theory study
Authors: Yang Po-Yu , Chen Hsing-Yin , Ju Shin-Pon , Chang Chia-Lin , Leu Gao-Shee , Lin Che-Hsin
Published: August 2018

The detailed reaction mechanism of naphthalene catalytic polymerization by HF/BF3 has been investigated by DFT calculations and the directionality of the naphthalene-derived mesophase molecule has been explained.
Ideal inert substrates for planar antimonene: h-BN and hydrogenated SiC(0001)
Authors: Zhang Shuai , Ma Yandong , Peng Rui , Huang Baibiao , Dai Ying
Published: August 2018

The electronic properties of planar antimonene are preserved well on two substrates: h-BN and hydrogenated SiC.
Visible-light photoexcitation of pyridine surface complex, leading to selective dehydrogenative cross-coupling with cyclohexane
Authors: Naniwa Shimpei , Tyagi Akanksha , Yamamoto Akira , Yoshida Hisao
Published: August 2018

A pyridine–TiO2 LMCT complex is excited by visible light to achieve selective DCC with cyclohexane via a unique reaction mechanism.
Direct dehydrogenation of isobutane to isobutene over Zn-doped ZrO2 metal oxide heterogeneous catalysts
Authors: Liu Yang , Xia Chengjie , Wang Qi , Zhang Lei , Huang Ao , Ke Ming , Song Zhaozheng
Published: August 2018

A series of unconventional nano-sized Zn-doped ZnZrO-x catalysts are applied for the first time to the direct dehydrogenation of isobutane to isobutene.
Computational chemical analysis of Eu(iii) and Am(iii) complexes with pnictogen-donor ligands using DFT calculations
Authors: Kimura Taiki , Kaneko Masashi , Watanabe Masayuki , Miyashita Sunao , Nakashima Satoru
Published: August 2018

High selectivity of a P-donor ligand for Am(iii) over Eu(iii) is comparable to the soft acid classification of the HSAB rule and can be correlated with the covalency in f-orbital type MO surfaces.
Enzymatic digest of whey protein and wheylin-1, a dipeptide released in the digest, increase insulin sensitivity in an Akt phosphorylation-dependent manner
Authors: Ogiwara Maiko , Ota Wakana , Mizushige Takafumi , Kanamoto Ryuhei , Ohinata Kousaku
Published: August 2018

Wheylin-1 is the first whey-derived peptide that increases insulin sensitivity in an Akt phosphorylation-dependent manner and lowers blood glucose levels.
Anti-oxidative and anti-inflammatory effects of Rosa Mosqueta oil supplementation in rat liver ischemia-reperfusion
Authors: Dossi Camila G. , González-Mañán Daniel , Romero Nalda , Silva David , Videla Luis A. , Tapia Gladys S.
Published: August 2018

Ischemia-reperfusion (IR) is a deleterious condition associated with liver transplantation or resection that involves pro-oxidant and pro-inflammatory mechanisms.
Dietary chlorogenic acid supplementation affects gut morphology, antioxidant capacity and intestinal selected bacterial populations in weaned piglets
Authors: Zhang Yong , Wang Yu , Chen Daiwen , Yu Bing , Zheng Ping , Mao Xiangbing , Luo Yuheng , Li Yan , He Jun
Published: August 2018

Chlorogenic acid (CGA), an ester formed between caffeic acid and quinic acid, is one of the most abundant phenolic acids in plants.
Interlayer crosslinking to conquer the stress relaxation of graphene laminated materials
Authors: Yang Mincheng , Xu Zhen , Li Peng , Guo Fan , Liu Yingjun , Xiao Youhua , Gao Weiwei , Gao Chao
Published: August 2018

Severe stress relaxation was found in macroscopically assembled graphene papers and was conquered by interlayer crosslinking.
Ultrafast synthesis of ultrasmall polyethylenimine-protected AgBiS2 nanodots by “rookie method” for in vivo dual-modal CT/PA imaging and simultaneous photothermal therapy
Authors: Lei Pengpeng , An Ran , Zheng Xiaohua , Zhang Peng , Du Kaimin , Zhang Manli , Dong Lile , Gao Xuan , Feng Jing , Zhang Hongjie
Published: August 2018

Ultrasmall PEI-AgBiS2 nanodots were synthesized using an ultra-facile strategy, which could be used as highly efficient cancer theranostic agent.
An off–on fluorescent probe for the detection of mitochondria-specific protein persulfidation
Authors: Meng Wenqi , Chen Yongchun , Feng Yongwei , Zhang Hao , Xu Qingqiang , Sun Mingxue , Shi Wenwen , Cen Jinfeng , Zhao Jie , Xiao Kai
Published: August 2018

A fluorescent probe for the detection of mitochondrial protein persulfidation, and featuring fast reaction, good selectivity and high sensitivity, was developed.
Domino aza/oxa-hetero-Diels–Alder reaction for construction of novel spiro[pyrido[3′,2′:5,6]pyrano[2,3-d]pyrimidine-7,5′-pyrimidine]
Authors: Yang Wen-Juan , Sun Qiu , Sun Jing , Yan Chao-Guo
Published: August 2018

The unprecedented reaction of α,β-unsaturated N-arylaldimines with two molecular 5-arylidene-1,3-dimethylbarbituric acids in methylene dichloride at room temperature afforded unique spiro[pyrido[3′,2′:5,6]pyrano[2,3-d]pyrimidine-7,5′-pyrimidines] in moderate to good yields and with high diastereoselectivity.
Three dimensional modelling of the components in supercapacitors for proper understanding of the contribution of each parameter to the final electrochemical performance
Authors: Barzegar Farshad , Zhang Lijun , Bello Abdulhakeem , Manyala Ncholu , Xia Xiaohua
Published: August 2018

Three dimension (3D) modelling of supercapacitors (SCs) has been investigated for the first time to have a better understanding of and study the effect of each parameter on the final electrochemical results.
Biomass-derived C/N co-doped Ni(OH)2/NixSy with a sandwich structure for supercapacitors
Authors: Zhang Yue , Yu Lei , Hu Rudan , Zhang Jianli , Wang Yining , Niu Richao , Qian Xingyue , Zhu Junwu
Published: August 2018

C/N co-doped Ni(OH)2/NixSy with a sandwich structure was designed via a simple one-step hydrothermal method for supercapacitors with excellent cycling stability.
Topological tailoring of structure and defects to enhance red to near-infrared afterglow from Mn2+-doped germanate photonic glasses
Authors: Luo Haoyang , Cao Jiangkun , Li Xingyu , Wang Xiu , Peng Mingying
Published: August 2018

By tailoring the structure and defects in glass promoting the incorporation and stabilization of Mn2+, the afterglow properties can be flexibly regulated from 30 min to longer than 24 h, which provides accessible knowledge in designing persistent glass.
High efficiency red emission carbon dots based on phenylene diisocyanate for trichromatic white and red LEDs
Authors: Han Zhixia , Wang Kai , Du Fanglin , Yin Zhengmao , Xie Zheng , Zhou Shuyun
Published: August 2018

Recently, carbon dots have emerged as novel luminous materials due to their excellent luminous performance.
Hyperspectral band selection using crossover‐based gravitational search algorithm
Authors: Zhang Aizhu , Ma Ping , Liu Sihan , Sun Genyun , Huang Hui , Zabalza Jaime , Wang Zhenjie , Lin Chengyan
Published: August 2018

Band selection is an important data dimensionality reduction tool in hyperspectral images (HSIs). To identify the most informative subset band from the hundreds of highly corrected bands in HSIs, a novel hyperspectral band selection method using a crossover‐based gravitational search algorithm (CGSA) is presented in this study. In this method, the discriminative capability of each band subset is evaluated by a combined optimisation criterion, which is constructed based on the overall classification accuracy and the size of the band subset. As the evolution of the criterion, the subset is updated using the V‐shaped transfer function‐based CGSA. Ultimately, the band subset with the best fitness value is selected. Experiments on two public hyperspectral datasets, i.e. the Indian Pines dataset and the Pavia University dataset, have been conducted to test the performance of the proposed method. Comparing experimental results against the basic GSA and the PSOGSA (hybrid PSO and GSA) revealed that all of the three GSA variants can considerably reduce the band dimensionality of HSIs without damaging their classification accuracy. Moreover, the CGSA shows superiority on both the effectiveness and efficiency compared to the other two GSA variants.
One‐bit compressive sensing with time‐varying thresholds in synthetic aperture radar imaging
Authors: Demir Mehmet , Erçelebi Ergun
Published: August 2018

In this study, the authors introduce a new framework for 1‐bit compressed synthetic aperture radar (SAR) imaging by using time‐varying thresholding. They show how to recover sparse SAR images from noisy measurements which have been quantised to 1‐bit with time‐varying thresholds. In the conventional 1‐bit compressive sensing (CS) SAR imaging methods, 1‐bit quantisation is implemented by comparing the received signal to a zero threshold. This makes the information about the magnitude of the signal to be lost and exact signal recovery becomes impossible. One‐bit quantisation with time‐varying thresholds allows them to reconstruct the magnitude of the signal more accurately and an explicit unit‐norm constraint is no longer required in the proposed optimisation formulation. Using the proposed approach, the authors formulate 1‐bit CS SAR imaging reconstruction problem as an unconstrained optimisation problem where the objective function includes an data‐fidelity term and a non‐smooth regularisation function. In order to solve this unconstrained optimisation problem, they use variable splitting and the alternating direction method of multipliers based approach which is computationally efficient and easy to implement. The results from experiments with synthetic and real SAR images validate the effectiveness of the proposed method named as BCST‐SAR (binary CS with time‐varying thresholds in SAR imaging).
LPI time‐based TMS against high‐sensitivity ESM
Authors: Wang Fei , Yu Siwei , Shi Chenguang , Sellathurai Mathini
Published: August 2018

Low probability of interception (LPI) time refers to a time during which a certain airborne radar system is tracking the target without being intercepted by a high‐sensitivity electronic support measurement (HSESM) on the target. LPI time is determined by the tracking process of the certain airborne radar system and the interception performance of an HSESM. This study proposes a track mission shifting (TMS) tactic of the distributed airborne radar system (DARS) or distributed airborne formation radar system (DAFRS) based on LPI time. First, this study defines a short‐time average interception probability of HSESM on frequency search mode. Then, with adaptive dwell time design and the maximum illumination interval algorithm based on predicted tracking error covariance matrix, this study proposes to take interactive multiple models Kalman filter to describe target tracking process and introduces binary hypothesis test of chi‐square and non‐central chi‐square distributions as target detection criterion during target tracking. Finally, with a partial prior knowledge of the opposed HSEMS on the target, this study proposes a TMS tactic model based on LPI time. Simulations show that LPI time is a significant reference value for DARS or DAFRS to turn over track mission against an opposed HSEMS.
Kinematics analysis and experiment of a lily picking mechanical arm
Authors: Jiang Ao , Yao Xiang , Cheng Ming , Zhou Juan
Published: August 2018

A lily flower is a medicinal plant, which has been widely used in the Chinese medicine industry in recent years. According to the rapid picking of the lily flower, a scheme of the mechanical arm picking structure was designed, and the system with an end effector, manipulator and control system was used. The mechanical arm adopts a three‐stage connecting rod structure. Through the lily plant growth of more than about 85% <50 cm characteristics of the mechanical arm were picked up from the top to bottom operation strategy. Based on this, the kinematics model of the picking robotic manipulator is designed. The kinematic equation of the manipulator is demonstrated by a DH deducing method. The kinematics simulation of the manipulator is carried out by MATLAB. The mechanical arm kinematics and picking experiments were carried out in the experimental field in a natural environment by the robotic physical machine platform. The results showed that the manipulator position error from the end of the arm was <12 mm and the picking success rate was 83.33%.
Research on path planning of real‐time obstacle avoidance of mechanical arm based on genetic algorithm
Authors: Jiang Ao , Yao Xiang , Zhou Juan
Published: August 2018

Aiming at the problem that modular mechanical arm may collide with the obstacles in working space at runtime, a path planning algorithm of obstacle avoidance is proposed based on a genetic algorithm (GA). Firstly, the Denavit–Hartenberg method is applied to the modelling of the mechanical arm; then, the kinematic and kinetic analysis is conducted and the kinematic and kinetic equations of the mechanical arm are established. On this basis, the time, spatial distance and path length of the motion are regarded as optimising indices and the optimisation of path planning of obstacle avoidance is achieved using GA for mechanical arm under a working condition with single obstacle or multiple obstacles. Through simulation, the effectiveness and feasibility of a path planning algorithm of mechanical arm obstacle avoidance based on GA is verified. This algorithm improves the efficiency of a mechanical arm to avoid the obstacles in working space at runtime.
Scene classification of remote sensing images based on hierarchical sparse coding
Authors: Jiaqing Xu , Qi Lv , Hongjun Liu , Jie He
Published: August 2018

Remote sensing image scene classification is an important method for remote sensing image analysis and interpretation and plays an important role in civil and military fields. In this study, a scene classification method of remote sensing images based on hierarchical sparse coding is proposed. This method is essentially a kind of multi‐layer, multi‐scale, and multi‐path sparse coding. It can extract features of optical remote sensing images more effectively, so that the features of the remote sensing images can be represented more sufficiently. The obtained codes are further used for spatial pyramid pooling (SPP) operation, and the corresponding SPP representation is obtained. SPP representations in different paths are combined and outputted to the support vector machine classifier, and the final classification results are obtained. Experiments on two data sets show that the proposed method can obtain better scene classification accuracy.
Study on control strategy for personalised lane‐change on highway
Authors: Cheng Senlin , Wang Chuanhai , Zhang Shuangteng , Zong Ruixue , Deng Xinli
Published: August 2018

The driving assistant system is conducive to reduce the accidents caused by operational mistakes in the complex environment of lane‐change on the highway. However, the adaptability between the system and drivers has not been taken into consideration. To solve this problem, this study put forward a personalised driving assistant strategy in the process of highway lane‐change. In the study, as a methodology based on the measured data of vehicle dynamic characteristics and personalised driving characteristics, it established a criterion for the personalised driving model, dissected the factors affecting driving safety and put forward a risk assessment method for individualised driving according to the criterion. Taken Matlab/Simulink software as a simulation experiment platform, it verified the rationality and feasibility of the individualised driving‐aid strategy of highway lane‐change with the aid of the adaptive model predictive control algorithm. The study results show that the personalised driving criterion and risk assessment method proposed in this study can effectively distinguish the driving styles and driving risks of different drivers, and the personalised driving assistance strategy not only respects different drivers’ individualised operation styles but also effectively controls driving risks.
Defect detection of PCB based on Bayes feature fusion
Authors: Lu Zhisheng , He Qinqin , Xiang Xinguang , Liu Hong
Published: August 2018

With the continuous development of the electronics industry, the number of printed circuit board (PCB) has grown at a rapid rate, and the requirements for the detection systems of PCB have also continuously increased. In the traditional PCB detection, the main reference is the comparison method. However, in a real scene, there are a series of problems such as non‐uniform illumination, tilting of the camera angle, and the like, resulting in a less satisfactory effect of the reference comparison method. So, the authors proposed a non‐reference comparison framework of PCB defects detection. This framework has achieved good results in speed and accuracy. The authors extract the histogram of oriented gradients and local binary pattern features for each PCB image, respectively, put into the support vector machine to get two independent models. Then, according to Bayes fusion theory, the authors fuse two models for defects classification. The authors have established a PCB data set that includes both defective and defect‐free. It has been verified that the accuracy of the verification set is improved compared to the individual features using the fused features. The authors also illustrate the effectiveness of Bayes feature fusion in terms of speed.
CNN‐based reference comparison method for classifying bare PCB defects
Authors: Wei Peng , Liu Chang , Liu Mengyuan , Gao Yunlong , Liu Hong
Published: August 2018

Printed circuit board (PCB) inspection is an essential part of PCB production process. Traditional PCB bare board defect detection methods have their own defects. However, the PCB bare board defect detection method based on automatic optic inspection is a feasible and effective method, and it is having more and more application in industry. Based on the idea of the reference comparison method, this study aims at studying the classification of defects. First of all, the method of extracting defect areas using morphology is studied; meanwhile, a data set containing 1818 images with 6 different detailed defect area image parts are produced. Then, in order to classify defects accurately, a traditional classification algorithm based on digital image processing was attempted, and a defect classification algorithm based on convolutional neural network was proposed. After experimental demonstration, in the actual results, the defect classification algorithm based on convolutional neural network can achieve a fairly high classification accuracy (95.7%), which is much higher than the traditional method, and the new method has stronger stability than the traditional one.
Accurate image registration method for PCB defects detection
Authors: Hua Guoliang , Huang Weipeng , Liu Hong
Published: August 2018

Image registration technology has been widely used in many parts of the computer vision system such as the automatic optical inspection system which is used to detect the printed circuit board (PCB) defects. The accuracy of the image registration will deeply influence the system's performance, so this study proposed an accurate image registration algorithm and applied it to the PCB defect detection. Good features to track feature detector and speeded up robust feature descriptor are combined to extract efficient features to achieve the first accurate image registration. Afterwards, cross‐correlation functions were used to compute the shift between the reference image and the first‐registered image for further accurate registration. Experimental results show that the authors’ algorithm performs a much better registration, with a lower root‐mean‐square error value between the reference image and transformed image. What is more, they applied it to detect the defects of PCB with a high accuracy.
Intelligent scheduling method for energy saving operation of multi‐train based on genetic algorithm and regenerative kinetic energy
Authors: Zou Bingqian , Gong Lixiong , Yu Ning , Chen Jin
Published: August 2018

An intelligent scheduling method for energy saving operation of multi‐train is proposed based on genetic algorithm and regenerative kinetic energy. Considering the morning and evening peak, departure time, and total vehicle number, the energy consumption optimisation model of multidimensional state vector subspace of train is established for the train departure interval with the lowest total energy consumption. Two intelligent control models are used to formulate the time interval scheduling plan depending on whether to consider the morning and evening peak. The train operation diagram is solved by Matlab, and the validity and feasibility of the proposed algorithm are verified. This study provides an intelligent and efficient algorithm and solution for multi‐train intelligent scheduling problem.
Improved bare PCB defect detection approach based on deep feature learning
Authors: Zhang Can , Shi Wei , Li Xiaofei , Zhang Haijian , Liu Hong
Published: August 2018

Robust and precise defect detection is of great significance in the production of the high‐quality printed circuit board (PCB). However, due to the complexity of PCB production environments, most previous works still utilise traditional image processing and matching algorithms to detect PCB defects. In this work, an improved bare PCB defect detection approach is proposed by learning deep discriminative features, which also greatly reduced the high requirement of a large dataset for the deep learning method. First, the authors extend an existing PCB defect dataset with some artificial defect data and affine transformations to increase the quantity and diversity of defect data. Then, a deep pre‐trained convolutional neural network is employed to learn high‐level discriminative features of defects. They fine‐tune the base model on the extended dataset by freezing all the convolutional layers and training the top layers. Finally, the sliding window approach is adopted to further localise the defects. Extensive comparisons with three traditional shallow feature‐based methods demonstrate that the proposed approach is more feasible and effective in PCB defect detection area.
Research on intelligent dispatching strategy of power grid using multi‐agent and knowledge discovery algorithm
Authors: Wang Yanan , Wu Jiekang , Mao Xiaoming
Published: August 2018

Renewable energy has great significance in environmental protection, economical conservation, and energy utilisation. Under the premise of making full use of available energy, the rational allocation and dispatch of distributed energy is the prerequisite for reliable and stable operation of urban power grid. According to the types of energy, this study divides into energy supply agent, energy demand agent, and energy dispatch agent, and establishes the multi‐agent system (MAS) model of urban power grid. Use knowledge discovery algorithms to formulate scheduling plans to achieve economic development, environment‐friendly, and other multi‐objective optimisation. The simulation results show that the use of knowledge discovery algorithm to solve the MAS model for emergency dispatch of electric energy can effectively guarantee the scheduling request and energy supply of the lean areas in various situations.
Optimisation design investigation of a cylindrical end curve towards a non‐continuous profile of a cam mechanism
Authors: Sun Jing , Liu Xiaoqing , Yin Zhongwang , Zeng Ting , Su Tinghui , Ding Xiaoxi , Shao Yimin
Published: August 2018

Cylindrical end cam mechanisms are widely used in many engineering machineries, which mainly contribute to the transmission of movement and power. However, due to the stress of time variation and instability in the operating process, it generally causes vibrations and impacts of the mechanical equipment, and leads to failures or even damage to the machine. Aiming at the issue about the excessive lateral impact forces of support and anti‐twist roller shaft, a new optimisation design method of the end cam curve is proposed. The simulation results show that the proposed method can effectively reduce the lateral impact, and solve the failure problem caused by excessive impact forces in the application of the non‐continuous profile of the cam mechanism. In addition, multi‐body dynamic analysis is used to verify the effectiveness of the optimisation method. Meanwhile, this optimisation method also has a certain reference significance to solve similar problems.
Incremental multivariate Markov chain model
Authors: Yang Chuan‐sheng , Zheng Yu‐jia , Wang Chao
Published: August 2018

In this study, the authors present an incremental multivariate Markov (IMM) chain model. Moreover, the estimation method of the parameters in IMM is proposed. Numerical experiments illustrate the effectiveness of IMM.
Convolutional neural network‐based multi‐label classification of PCB defects
Authors: Zhang Linlin , Jin Yongqing , Yang Xuesong , Li Xia , Duan Xiaodong , Sun Yuan , Liu Hong
Published: August 2018

Due to the rapid development of printed circuit board (PCB) design technology, inspection of PCB surface defects has become an increasingly critical issue. The classification of PCB defects facilitates the root causes of detects’ identification. As PCB defects may be intensive, the actual PCB classification should not be considered as a binary or multi‐category problem. This type of problem is called multi‐label classification problem. Recently, as one of the deep learning frameworks, a convolutional neural network (CNN) has a major breakthrough in many areas of image processing, especially in the image classification. This study proposes a multi‐task CNN model to handle the multi‐label learning problem by defining each label learning as a binary classification task. In this study, the multi‐label learning is transformed into multiple binary classification tasks by customising the loss function. Extensive experiments demonstrate that the proposed method achieves great performance on the dataset of defects.
Influence of the hybrid‐driven method on the electromagnetic properties of an electromagnetic motor
Authors: Zhao Jing‐Bo , Liu Hai‐Mei , Bei Shao‐Yi
Published: August 2018

In the light of an electromagnetic motor driving system, electromagnetic conversion characteristics and structural principles were described. Electromagnetic drive and hybrid‐driven method were proposed; the mathematical models describing the two drive systems which have adopted the magnetic circuit analysis method were established, starting with a discussion on how the drive system affects the electromagnetic force and air‐gap magnetic flux density. Under the same conditions, the electromagnetic drive and hybrid‐driven model were, respectively, simulated to reveal the impact on the electromagnetic force and air‐gap magnetic flux density due to the different driving modes. Variation of the electromagnetic force with an increasing coil current of two types of drive systems under motor speed control is studied preliminarily. The results have shown that compared to that of the pure electromagnetic drive system, the electromagnetic force of the hybrid drive system was raised from 2198 to 4097 N, and the air‐gap magnetic flux density was increased from 1.048 to 1.393 T; the electromagnetic characteristics of the magnetically driven motor were improved effectively.
New microscopic image sequence‐driven cell deformation model
Authors: He Fuyun , Jiang F. , Jiang Yanyan , Ling Sai Ho
Published: August 2018

It is of great significance that making quantitative description and analysis of the cell morphological change to explore physiological or pathological status of the life. To achieve the cells morphological changes of quantitative description, the authors constructed a cell deformation model based on microscopic image sequence here. Based on the graph regularisation and structured matrix decomposition, the high‐dimensional shape space is represented by the linear combination of the low‐dimension subshape space, so that the authors get a quantitative indicator which represents the degree of cell deformation–deformation factor. In order to verify the validity of the authors’ model, a deformation feature extraction experiment was performed on three groups of stem cell image sequence with different deformation degree. Compared with other three common quantitative methods of deformation, the authors’ model describes the cell morphological changes more comprehensively, and has better adaptability and stability for describing the diversity of cell movements.