Sequence stratigraphy, paleogeography, and coal accumulation regularity of major coal-accumulating periods in China

There are 9 major coal-accumulating periods during geological history in China,including the Early Carboniferous,Late Carboniferous-Early Permian,Middle Permian,Late Permian,Late Triassic,Early-Middle Jurassic,Early Cretaceous,Paleogene and Neogene.The coal formed in these periods were developed in different coal-accumulating areas(CAA)including the North China,South China,Northwest China,Northeast China,the Qinghai–Tibet area,and China offshore area.In this paper,we investigated depositional environments,sequence stratigraphy,lithofacies paleogeography and coal accumulation pattern of five major coal-accumulating periods including the Late Carboniferous to Middle Permian of the North China CAA,the Late Permian of the South China CAA,the Late Triassic of the South China CAA,the Early-Middle Jurassic of the North and Northwest China CAA,and the Early Cretaceous in the Northeast China CAA.According to distribution of the coal-bearing strata and the regional tectonic outlines,we have identified distribution range of the coal-forming basins,sedimentary facies types and coal-accumulating models.The sequence stratigraphic frameworks of the major coal-accumulating periods were established based on recognition of a variety of sequence boundaries.The distribution of thick coals and migration patterns of the coal-accumulating centers in the sequence stratigraphic framework were analyzed.The lithofacies paleogeography maps based on third-order sequences were reconstructed and the distribution of coal accumulation centers and coal-rich belts were predicted.

A study of sequence stratigraphy of the Early Cretaceous coal-bearing series in the southeastern Songliao Basin, NE China

The Early Cretaceous is an important coal accumulation period in China.Abundant coal resources were formed in the southeastern margin of Songliao Basin.Sequence stratigraphy and coal accumulation of the Early Cretaceous in the southeastern margin of Songliao Basin have been studied on the basis of extensive outcrop and borehole data.Based on regional unconformity,basal erosional surfaces of incised valley fills,and abrupt depositional facies-reversal surface,six sequence boundaries have been identified,which subdivide the Early Cretaceous coal-bearing series into 5 third-order sequences.Sequence I corresponds to Huoshiling Formation,sequences II and III correspond to member I and member II of Shahezi Formation.Sequences IV and V correspond to member I and member II of Yingcheng Formation.Sequence I developed at the initial subsiding stage,sequence II and III developed during the stable subsiding stage,while sequence IV and V developed during the basin shrinkage stage.The major coal seams were developed in the sequence II and III,which ensured the relative balance between the increase rate of the accommodation space and the rate of peat accumulation for a longer period,thus forming a thick coal seam.

Green Hydrothermal Synthesis and Applications of Sorbus pohuashanensis/Aronia melanocarpa Extracts Functionalized-Au/Ag/AuAg Nanoparticles

Nanoparticles(NPs)have already been widely used in catalysis,antibacterial and coating fields.Compared with the traditional toxic and harmful reducing reagents,green synthesis of NPs by using plant extracts is not only environmental-friendly and cost-effective but also conducive to the multi-level and efficient utilization of wild plant resources.In this study,the aqueous extracts from Sorbus pohuashanensis(SP)and Aronia melanocarpa(AM)fruits were used as the reducing and protective reagents for synthesizing Au/AgNPs,with the characteristics of originality operation and high repeatability.The SP/AM fruit extracts functionalized Au/AgNPs were characterized by UV-vis spectroscopy(UV-vis),transmission electron microscopy(TEM),energy dispersive spectroscopy(EDS),scanning electron microscope(SEM),X-ray diffraction(XRD)and Fourier transform infrared spectroscopy(FTIR).UV-vis spectrums showed the NPs peaks verified by the presence between 400–550 nm;TEM and SEM demonstrated NPs displayed approximately spherical structures;EDS confirmed the existence of Au/Ag elements;XRD measurements confirmed that the obtained NPs showed highly crystalline structures;FTIR demonstrated the fruits extracts were adsorbed on the surface of NPs.Primary experiments indicated that SP/AM fruit extracts functionalized-NPs could be used as the reagents for removing the organic dyes efficiently;Zone of inhibition tests(ZOI)explained that NPs have slow-release antibacterial activity.

Integrating BDS and GPS for precise relative orbit determination of LEO formation flying

Low-Earth-Orbit（LEO） formation-flying satellites have been widely applied in many kinds of space geodesy. Precise Relative Orbit Determination（PROD） is an essential prerequisite for the LEO formation-flying satellites to complete their mission in space. The contribution of the BeiDou Navigation Satellite System（BDS） to the accuracy and reliability of PROD of LEO formation-flying satellites based on a Global Positioning System（GPS） is studied using a simulation method. Firstly, when BDS is added to GPS, the mean number of visible satellites increases from9.71 to 21.58. Secondly, the results show that the 3-Dimensional（3 D） accuracy of PROD, based on BDS-only, GPS-only and BDS ＋ GPS, is 0.74 mm, 0.66 mm and 0.52 mm, respectively. When BDS co-works with GPS, the accuracy increases by 29.73%. Geostationary-Earth-Orbit（GEO） satellites and Inclined Geosynchronous-Orbit（IGSO） satellites are only distributed over the Asia-Pacific region; however, they could provide a global improvement to PROD. The difference in PROD results between the Asia-Pacific region and the non-Asia-Pacific region is not apparent. Furthermore, the value of the Ambiguity Dilution Of Precision（ADOP）, based on BDS ＋ GPS, decreases by 7.50% and 8.26%, respectively, compared with BDS-only and GPS-only. Finally, if the relative position between satellites is only a few kilometres, the effect of ephemeris errors on PROD could be ignored. However, for a several-hundred-kilometre separation of the LEO satellites, the SingleDifference（SD） ephemeris errors of GEO satellites would be on the order of centimetres. The experimental results show that when IGSO satellites and Medium-Earth-Orbit（MEO） satellites co-work with GEO satellites, the accuracy decreases by 17.02%.

Kernel-blending connection approximated by a neural network for image classification

This paper proposes a kernel-blending connection approximated by a neural network(KBNN)for image classification.A kernel mapping connection structure,guaranteed by the function approximation theorem,is devised to blend feature extraction and feature classification through neural network learning.First,a feature extractor learns features from the raw images.Next,an automatically constructed kernel mapping connection maps the feature vectors into a feature space.Finally,a linear classifier is used as an output layer of the neural network to provide classification results.Furthermore,a novel loss function involving a cross-entropy loss and a hinge loss is proposed to improve the generalizability of the neural network.Experimental results on three well-known image datasets illustrate that the proposed method has good classification accuracy and generalizability.

Controllable broadband multicolour single-mode polarized laser in a dye-assembled homoepitaxial MOF microcrystal

Multicolour single-mode polarized microlasers with visible to near-infrared output have very important applications in photonic integration and multimodal biochemical sensing/imaging but are very difficult to realize.Here,we demonstrate a single crystal with multiple segments based on the host-guest metal-organic framework ZJU-68 hierarchically hybridized with different dye molecules generating controllable single-mode green,red,and nearinfrared lasing,with the lasing mode mechanism revealed by computational simulation.The segmented and oriented assembly of different dye molecules within the ZJU-68 microcrystal causes it to act as a shortened resonator,enabling us to achieve dynamically controllable multicolour single-mode lasing with a low three-colour-lasing threshold of ~1.72 mJ/cm^(2)(approximately seven times lower than that of state-of-the-art designed heterostructure alloys,as reported by Fan F et al.(Nat.Nanotechnol.10:796-803,2015)considering the single pulse energy density)and degree of polarization>99.9%.Furthermore,the resulting three-colour single-mode lasing possesses the largest wavelength coverage of ~186 nm(ranging from ~534 to ~720 nm)ever reported.These findings may open a new route to the exploitation of multicolour single-mode micro/nanolasers constructed by MOF engineering for photonic and biochemical applications.

Precise orbit determination for TH02-02 satellites based on BDS3 and GPS observations

The Tianhui-202(TH02-02)satellite formation,as a supplement to the microwave mapping satellite system Tianhui-201(TH02-01),is the first Interferometric Synthetic Aperture Radar(InSAR)satellite formation-flying system that supports the tracking of BeiDou global navigation Satellite system(BDS3)new B1C and B2a signals.Meanwhile,the twin TH02-02 satellites also support the tracking of Global Positioning System(GPS)L1&L2 and BDS B1I&B3I signals.As the spaceborne receiver employs two independent boards to track the Global Navigation Satellite System(GNSS)satellites,we design an orbit determination strategy by estimating independent receiver clock offsets epoch by epoch for each GNSS to realize the multi-GNSS data fusion from different boards.The performance of the spaceborne receiver is evaluated and the contribution of BDS3 to the kinematic and reduced-dynamic Precise Orbit Determination(POD)of TH02-02 satellites is investigated.The tracking data onboard shows that the average number of available BDS3 and GPS satellites are 8.7 and 9.1,respectively.The carrier-to-noise ratio and carrier phase noise of BDS3 B1C and B2a signals are comparable to those of GPS.However,strong azimuth-related systematic biases are recognized in the pseudorange multipath errors of B1C and B3I.The pseudorange noise of BDS3 signals is better than that of GPS after eliminating the multipath errors from specific signals.Taking the GPS-based reduced-dynamic orbit with single-receiver ambiguity fixing technique as a reference,the results of BDS3-only and BDS3+GPS combined POD are assessed.The Root Mean Square(RMS)of orbit comparison of BDS3-based kinematic and reduced-dynamic POD with reference orbit are better than 7 cm and 3 cm in three-Dimensional direction(3D).The POD performance based on B1C&B2a data is comparable to that based on B1I&B3I.The precision of BDS3+GPS combined kinematic orbit can reach up to 3 cm(3D RMS),which has a more than 25%improvement relative to the GPS-only solution.In addition,the consistency between the BDS3+GPS combined reduced-dynamic orbit and the GPS-based ambiguity-fixed orbit is better than 1.5 cm(3D RMS).

Bilateral thalamic lesions caused by a complex intracranial dural arteriovenous fistula: a rare case report

To the Editor:Bilateral thalamic lesions are uncomm on,but the different types of pathogenesis can be classified into metabolic processes,toxic exposures,infection,vascular lesions,and tumors.111 Among the possible forms of pathogenesis,intracranial dural arteriovenous fistula(dAVF)is extremely rare.

Enhanced baseline determination for formation flying LEOs by relative corrections of phase center and code residual variations

Formation flying Low Earth Orbiters(LEOs)are important for implementing new and advanced concepts in Earth observation missions.Precise Baseline Determination(PBD)is a prerequisite for LEOs to complete specified mission targets.PBD is usually performed based on space-borne GNSS data,the relative corrections of phase center and code residual variations play crucial roles in achieving the best relative orbit accuracy.Herein,the influences of antenna Relative Phase Centre Variations(RPCVs)and Single-Difference(SD)Melbourne-Wu¨bbena(MW)Combination Residuals Variations(SD MWVs)on PBD are studied.The methods were tested using flight data from Gravity Recovery And Climate Experiment(GRACE)and GRACE Follow-On(GRACE-FO).Results showed that the maximum values for RPCVs and SD MWVs were 14 mm and 0.32 cycles,respectively.Then,the RPCVs correction significantly enhanced the baseline accuracy;the K-Band Ranging(KBR)measurement consistency improved by 30.1%and 37.5%for GRACE and GRACE-FO,respectively.The application of SD MWVs further improved the accuracy and reliability of PBD results.For GRACE,the ambiguities fixing success rate increased from 85.1%to 97.9%and a baseline consistency of 0.57 mm was achieved for the KBR measurements.It was found that the correction of both RPCVs and SD MWVs reduced the carrier phase observation minus computation residuals from double-difference ionosphere-free combination.In addition,in-flight data processing demonstrated that RPCVs and SD MWVs estimations for the current period could be used for the previous and subsequent periods.

Multi-task regression learning for survival analysis via prior information guided transductive matrix completion

Survival analysis aims to predict the occurrence time of a particular event of interest,which is crucial for the prognosis analysis of diseases.Currently,due to the limited study period and potential losing tracks,the observed data inevitably involve some censored instances,and thus brings a unique challenge that distinguishes from the general regression problems.In addition,survival analysis also suffers from other inherent challenges such as the high-dimension and small-sample-size problems.To address these challenges,we propose a novel multi-task regression learning model,i.e.,prior information guided transductive matrix completion(PigTMC)model,to predict the survival status of the new instances.Specifically,we use the multi-label transductive matrix completion framework to leverage the censored instances together with the uncensored instances as the training samples,and simultaneously employ the multi-task transductive feature selection scheme to alleviate the overfitting issue caused by high-dimension and small-sample-size data.In addition,we employ the prior temporal stability of the survival statuses at adjacent time intervals to guide survival analysis.Furthermore,we design an optimization algorithm with guaranteed convergence to solve the proposed PigTMC model.Finally,the extensive experiments performed on the real microarray gene expression datasets demonstrate that our proposed model outperforms the previously widely used competing methods.

Progress in blood biomarkers of subjective cognitive decline in preclinical Alzheimer’s disease

Alzheimer's disease(AD)is a neurodegenerative disease that gradually impairs cognitive functions.Recently,there has been a conceptual shift toward AD to view the disease as a continuum.Since AD is currently incurable,effective intervention to delay or prevent pathological cognitive decline may best target the early stages of symptomatic disease,such as subjective cognitive decline(SCD),in which cognitive function remains relatively intact.Diagnostic methods for identifying AD,such as cerebrospinal fluid biomarkers and positron emission tomography,are invasive and expensive.Therefore,it is imperative to develop blood biomarkers that are sensitive,less invasive,easier to access,and more cost effective for AD diagnosis.This review aimed to summarize the current data on whether individuals with SCD differ reliably and effectively in subjective and objective performances compared to cognitively normal elderly individuals,and to find one or more convenient and accessible blood biomarkers so that researchers can identify SCD patients with preclinical AD in the population as soon as possible.Owing to the heterogeneity and complicated pathogenesis of AD,it is difficult to make reliable diagnoses using only a single blood marker.This review provides an overview of the progress achieved to date with the use of SCD blood biomarkers in patients with preclinical AD,highlighting the key areas of application and current challenges.

“Block and attack”strategy for tumor therapy through ZnO_(2)/siRNA/NIR-mediating Zn^(2+)-overload and amplified oxidative stress

Intracellular zinc ion(Zn^(2+))accumulation disrupts the Zn^(2+)homeostasis,providing an ion-overloading anticancer strategy with great potential.The self-adaptation of tumor cells to ion concentration,however,puts forward higher requirements for the design of ion-overloading strategy.Herein,“block and attack”antitumor strategy was applied through a composite nanomaterials(UHSsPZH NPs).The strategy demonstrated powerful ion interference ability through both“blocking”the efflux of excess Zn^(2+)via gene silencing and“attacking”tumor cells via target delivery of ZnO_(2).After cellular internalization,ZnO_(2) was degraded to Zn^(2+)and hydrogen peroxide(H_(2)O_(2)),and the gene expression of zinc transporter 1(ZnT1)was silenced by targeting of released siRNA,which together caused intracellular Zn2+-overload.Disorder of Zn^(2+)further interfered with intracellular Ca^(2+)homeostasis,inhibited the electron transport chain and promoted the production of endogenous reactive oxygen species(ROS),which assisted the“attack”to tumor cells together with the exogenous ROS generated by UHSsPZH NPs under 980 nm laser irradiation.In summary,this work supplies a“block and attack”strategy for the application of ion homeostasis interference in tumor therapy.