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Localized-states quantum confinement induced by roughness in CdMnTe/CdTe heterostructures grown on Si(111) substrates

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Journal of Semiconductors 2024年第9期45卷 28-35页

作者： Leonarde N.Rodrigues Wesley F.Inoch Marcos L.F.Gomes Odilon D.D.Couto Jr. Bráulio S.Archanjo Sukarno O.Ferreira Physics Department Federal University of ViçosaViçosa36570-900Minas GeraisBrazil Instituto de Física Gleb Wataghin Universidade Estadual de CampinasCampinas13083-859São PauloBrazil National Institute of metrology Quality and Technology(Inmetro) Materials Metrology Division(DIMAT)Xerém2525-020Rio de JaneiroBrazil

This work shows that despite a lattice mismatch of almost 20%, CdMnTe/CdTe/CdMnTe heterostructures grown directly on Si(111) have surprisingly good optical emission properties. The investigated structures were grown by molecular beam epitaxy and characterized by scanning transmission electron microscopy, macro-and micro-photoluminescence. Low temperature macro-photoluminescence experiments indicate three emission bands which depend on the CdTe layer thickness and have different confinement characteristics. Temperature measurements reveal that the lower energy emission band (at 1.48 eV)is associated to defects and bound exciton states, while the main emission at 1.61 eV has a weak 2D character and the higher energy one at 1.71 eV has a well-defined (zero-dimensional, 0D) 0D nature. Micro-photoluminescence measurements show the existence of sharp and strongly circularly polarized (up to 40%) emission lines which can be related to the presence of Mn in the heterostructure. This result opens the possibility of producing photon sources with the typical spin control of the diluted magnetic semiconductors using the low-cost silicon technology.

关键词： CdMnTe/CdTe/CdMnTe heterostructure CdTe/CdMnTe quantum emitters quantum dot-like emission silicon(111)substrate

Performance Study of MIMO-OSTBC Parallel Relay FSO System Based on GFDM

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Chinese Journal of Electronics 2024年第2期33卷 564-572页

作者： Rui ZHOU Yong WANG Yi WANG Key Laboratory of Electromagnetic Wave Information Technology and metrology of Zhejiang Province College of Information Engineering China Jiliang University State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hohai University

This paper investigates the performance of a new generalized frequency division multiplexing(GFDM)parallel relay free space optical(FSO) communication system using multi-input multi-output(MIMO) orthogonal space-time block codes(OSTBC) scheme. Under the M distribution atmospheric turbulence, taking into account the triple effects of irradiance, pointing errors and path loss, the mathematical expression of system symbol error rate is derived with the help of Meijer G-function. The symbol error performance of GFDM is compared with on-off keying,Gaussian minimum shift keying, polarization shift keying and orthogonal frequency division multiplexing(OFDM)modulation methods. The effects of the MIMO-OSTBC parallel relay scheme on the GFDM system including filter roll down coefficient, the number of transmitting and receiving antennas, the number of relays, normalized beamwidth and jitter variance are analyzed, and the numerical results are verified by Monte Carlo simulation. This work provides a good foundation for engineering applications.

关键词： Monte Carlo methods Transmitting antennas Symbols Receiving antennas Modulation Jitter Transceivers

Effect of grain boundary diffusion of terbium on mode of mechanical fracture of sintered NdFeB magnets

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Journal of Rare Earths 2024年第4期42卷 696-704页

作者： Zexin Lu Tinghui Wang Jianjun Jiang Bizhang Zheng Lijing Yang Xingqi He Anli Lin Shengzhi Dong Zhenlun Song CAS Key Laboratory of Magnetic Materials and Devices Zhejiang Province Key Laboratory of Magnetic Materials and Application TechnologyNingbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo315201China Faculty of Mechanical Engineering and Mechanics Ningbo UniversityNingbo315211China Ningbo Xinqi Precision Magnetism Steel Co. Ltd..Ningbo315156China Center for Advanced Measurement Science National Institute of MetrologyBeijing102200China division of Functional Materials Central Iron&Steel Research InstituteBeijing100081China

Grain boundary diffusion process(GBDP)is a widely used method of increasing the coercivity of sintered NdFeB *** this study,the effects of the GBDP on the bending strength and microhardness of sintered NdFeB magnets and the fracture mode were *** show that the bending strength of magnets is reduced by pickling and heat treatment and greatly recove rs after heavy rare earth element(Tb)grain boundary *** pickling and the heat treatment cause a slight decrease in *** with the recovery of the bending strength,the hardness decreases after the *** fracture mode of bended magnets changes from intergranular to *** study helps in further improving the mechanical and magnetic properties of sintered NdFeB magnets.

关键词： Sintered NdFeB magnets Grain boundary diffusionprocess Bending strength Heavy rare earth element Coercivity

AttentionSplice: An Interpretable Multi-Head Self-Attention Based Hybrid Deep Learning Model in Splice Site Prediction

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Chinese Journal of Electronics 2022年第5期31卷 870-887页

作者： YAN Wenjing ZHANG Baoyu ZUO Min ZHANG Qingchuan WANG Hong MAO Da division of Chemical metrology and Analytical Science National Institute of Metrology National Engineering Laboratory for Agri-Product Quality Traceability Beijing Technology and Business University

Pre-mRNA splicing is an essential procedure for gene transcription. Through the cutting of introns and exons, the DNA sequence can be decoded into different proteins related to different biological *** cutting boundaries are defined by the donor and acceptor splice sites. Characterizing the nucleotides patterns in detecting splice sites is sophisticated and challenges the conventional methods. Recently, the deep learning frame has been introduced in predicting splice sites and exhibits high performance. It extracts high dimension features from the DNA sequence automatically rather than infers the splice sites with prior knowledge of the relationships, dependencies, and characteristics of nucleotides in the DNA sequence. This paper proposes the Attention Splice model, a hybrid construction combined with multi-head self-attention, convolutional neural network, bidirectional long short-term memory *** performance of Attention Splice is evaluated on the Homo sapiens(Human) and Caenorhabditis Elegans(Worm) datasets. Our model outperforms state-of-the-art models in the classification of splice sites. To provide interpretability of Attention Splice models, we extract important positions and key motifs which could be essential for splice site detection through the attention learned by the model. Our result could offer novel insights into the underlying biological roles and molecular mechanisms of gene expression.

关键词： Splice sites Multi-head self-attention Bioinformatics Deep-learning Long short-term memory (LSTM) Convolutional neural network (CNN)

Enabling rapid X-ray CT characterisation for additive manufacturing using CAD models and deep learning-based reconstruction

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npj Computational Materials 2023年第1期9卷 1443-1452页

作者： Amirkoushyar Ziabari S.V.Venkatakrishnan Zackary Snow Aleksander Lisovich Michael Sprayberry Paul Brackman Curtis Frederick Pradeep Bhattad Sarah Graham Philip Bingham Ryan Dehoff Alex Plotkowski Vincent Paquit Energy and Electrification Infrastructure division Oak Ridge National LaboratoryKnoxvilleTN 37830USA ZEISS industrial metrology LLC Maple GroveMN 55369USA Manufacturing Science division Oak Ridge National LaboratoryOak RidgeTNUSA Materials Science and Technology division Oak Ridge National LaboratoryOak RidgeTNUSA

Metal additive manufacturing(AM)offers flexibility and cost-effectiveness for printing complex parts but is limited to few *** new alloys requires process parameter optimisation to produce consistent,high-quality ***-resolution X-ray computed tomography(XCT)has not been effective for this task due to artifacts,slow scan speed,and *** propose a deep learning-based approach for rapid XCT acquisition and reconstruction of metal AM parts,leveraging computer-aided design models and physics-based simulations of nonlinear interactions between X-ray radiation and *** significantly reduces beam hardening and common XCT *** demonstrate high-throughput characterisation of over a hundred AlCe alloy components,quantifying improvements in characterisation time and quality compared to high-resolution microscopy and *** approach facilitates investigating the impact of process parameters and their geometry dependence in metal AM.

关键词： rapid alloy character

Establishment of a metric to characterize retroreflector properties using a consumer-grade colour camera

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Transportation Safety and Environment 2023年第1期5卷 31-40页

作者： Huayang He Wenying Su Qiutong Cheng National Center of Metrization for Equipments of Roads and Bridges Research Institute of Highway Ministry of TransportBeijing 100088China division of Optical metrology National Institute of MetrologyBeijing 100029China

The coefficients of retroreflection and chromaticity coordinates are critical metrics for determining the quality of a ***,conventional retroreflection measurement techniques rely heavily on the night-time colour,size and characteristics of thesample being *** complicates the measurement process and leads to deviations in the test *** addition,chromaticitycannot be determined using this ***,it is necessary to improve the measurement accuracy,simplify themeasurement process and achieve themeasurement of the traffic sign RA and chromaticity coordinates *** this study,an improved method for retroreflector characterization using imaging was *** allowed for the measurement of the coefficientsof retroreflection and the chromaticity coordinates simultaneously,and only a white standard sample was required for *** primary components of the proposed system included a lighting projector,a receiver,two motorized rotational stages,a retroreflective sample holder and customized software that using scaling factors to convert a digital signal into sample retroreflectioncoefficients and retroreflective chromaticity *** experimental results indicated that the raw data output from thecamera exhibited a positive correlation relationship with the luminous flux from the surface of the *** maximummeasurementerrors for the retroreflection and chromaticity were−12.2 cd/(lx·m2)and−2.09%,*** was inexpensiveand convenient,used a commercially available digital camera,could help to identify defects in retroreflection and chromaticity forretroreflective sheeting and led to increased accessibility for the quality control of retroreflective sheeting.

关键词： camera chromaticity coordinates coefficient of retroreflection retroreflective sheeting retroreflector

Precise determination of characteristic laser frequencies by an Er-doped fiber optical frequency comb

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Chinese Physics B 2022年第7期31卷 327-335页

作者：曹士英韩羿丁永今林百科方占军 division of Time and Frequency metrology National Institute of MetrologyBeijing 100029China

Femtosecond optical frequency combs correlate the microwave and optical frequencies accurately and ***,any optical frequency in visible to near-infrared region can be directly traced to a microwave *** a result,the length unit“meter”is directly related to the time unit“second”.This paper validates the capability of the national wavelength standards based on a home-made Er-doped fiber femtosecond optical frequency comb to measure the laser frequencies ranging from visible to near-infrared *** frequency conversion in the femtosecond optical frequency comb is achieved by combining spectral broadening in a highly nonlinear fiber with a single-point frequencydoubling *** signal-to-noise ratio of the beat notes between the femtosecond optical frequency comb and the lasers at 633,698,729,780,1064,and 1542 nm is better than 30 d *** frequency instability of the above lasers is evaluated by using a hydrogen clock signal with a instability of better than 1×10^(-13)at 1-s averaging *** measurement is further validated by measuring the absolute optical frequency of an iodine-stabilized 532-nm laser and an acetylenestabilized 1542-nm *** results are within the uncertainty range of the international recommended *** results demonstrate the accurate optical frequency measurement of lasers at different frequencies using the femtosecond optical frequency comb,which is not only important for the precise and accurate traceability and calibration of the laser frequencies,but also provides technical support for establishing the national wavelength standards based on the femtosecond optical frequency comb.

关键词： optical frequency measurement phase lock Er-doped fiber laser fiber optical frequency comb

Recent progress on microfluidic biosensors for rapid detection of pathogenic bacteria

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Chinese Chemical Letters 2022年第4期33卷 1743-1751页

作者： Gaowa Xing Weifei Zhang Nan Li Qiaosheng Pu Jin-Ming Lin College of Chemistry and Chemical Engineering Lanzhou UniversityLanzhou 730000China Beijing Key Laboratory of Microanalytical Methods and Instrumentation Department of ChemistryTsinghua UniversityBeijing 100084China division of Chemical metrology and Analytical Science National Institute of MetrologyBeijing 100029China

Rapid on-site detection of pathogenic bacteria with high sensitivity and specificity is becoming an urgent need in public health assurance, medical diagnostics, environmental monitoring, and food safety fields. Despite being reliable and widely used, the existing methods of bacteria detection are cumbersome and time-consuming, which is not conducive to field detection. Microfluidic lab-on-a-chip technology has provided a detective tool for various analytes, due to its miniaturization, portability and low reagent consumption. Within this progress report, advances in the bacteria detection using microfluidic biosensors were discussed. Typical methods for pathogenic bacteria capture, separation and detection were introduced respectively in the first part. Then key applications of microfluidic biosensor-based rapid bacteria detection were presented. Finally, we made a conclusion and discussed possible research prospects in aspects of microfluidic biosensors for rapid detection of pathogenic bacteria.

关键词： Microfluidic chip Biosensors Pathogenic bacteria Rapid detection

Global characterization of modifications to the charge isomers of IgG antibody

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Journal of Pharmaceutical Analysis 2022年第1期12卷 156-163页

作者： Xinling Cui Wei Mi Zhishang Hu Xiaoyu Li Bo Meng Xinyuan Zhao Xiaohong Qian Tao Zhu Wantao Ying State Key Laboratory of Proteomics Beijing Proteome Research CenterNational Center for Protein Sciences(Beijing)Beijing Institute of LifeomicsBeijingChina National Institute of metrology Center for Advanced Measurement ScienceBeijingChina National Institute of metrology Chemical Metrology&Analytical Science DivisionBeijingChina CanSino Bio Corporation Tianjin Key Laboratory of Recombinant Bacterial Recombination and Bacterial Vaccines TianjinChina

Posttranslational modifications of antibody products affect their stability,charge distribution,and drug activity and are thus a critical quality *** comprehensive mapping of antibody modifications and different charge isomers(CIs)is of utmost importance,but is *** intended to quantitatively characterize the posttranslational modification status of CIs of antibody drugs and explore the impact of posttranslational modifications on charge *** CIs of antibodies were fractionated by strong cation exchange chromatography and verified by capillary isoelectric focusing-whole column imaging detection,followed by stepwise structural characterization at three ***,the differences between CIs were explored at the intact protein level using a top-down mass spectrometry approach;this showed differences in glycoforms and deamidation ***,at the peptide level,common modifications of oxidation,deamidation,and glycosylation were *** mapping showed nonuniform deamidation and glycoform distribution among *** total,10 N-glycoforms were detected by peptide ***,an in-depth analysis of glycan variants of CIs was performed through the detection of enriched *** and quantitative analyses demonstrated the dynamics of 24 *** results revealed that sialic acid modification is a critical factor accounting for charge heterogeneity,which is otherwise missed in peptide mapping and intact molecular weight *** study demonstrated the importance of the comprehensive analyses of antibody CIs and provides a reference method for the quality control of biopharmaceutical analysis.

关键词： Antibody Charge isomers Mass spectrometry Posttranslational modification Glycopeptide