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Fast method for spreading sequence estimation of DSSS signal based on maximum likelihood function

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Journal of Systems Engineering and Electronics 2010年第6期21卷 948-953页

作者： Yanhua Peng Bin tang ming Lv College of Electronic Engineering University of Electronic Science and Technology of China Chengdu 610054 E R. China

To estimate the spreading sequence of the direct sequence spread spectrum (DSSS) signal, a fast algorithm based on maximum likelihood function is proposed, and the theoretical derivation of the algorithm is provided. By simplifying the objective function of maximum likelihood estimation, the algorithm can realize sequence synchronization and sequence estimation via adaptive iteration and sliding window. Since it avoids the correlation matrix computation, the algorithm significantly reduces the storage requirement and the computation complexity. Simulations show that it is a fast convergent algorithm, and can perform well in low signal to noise ratio (SNR).

关键词： direct sequence spread spectrum (DSSS) signal spreading sequence maximum likelihood estimation (MLE).

High Mg# of the continental crust explained by calc-alkaline differentiation

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National Science Review 2023年第3期10卷 92-99页

作者： ming tang Xuanyu Liu Kang Chen Key Laboratory of Orogenic Belt and Crustal Evolution Ministry of Education School of Earth and Space Sciences Peking University State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences

We used compiled geochemical data to investigate the mechanisms that control Mg#(molar ratio of Mg/(Mg+FeT)) in andesitic arc *** find that andesites from mature continental arcs with crustal thickness of>45 km have systematically higher Mg# than those from oceanic arcs with crustal thickness of<30 *** elevated Mg# in continental arc lavas results from strong Fe depletion during high-pressure differentiation favored in thick *** proposal is reinforced by our compiled melting/crystallization experiment *** show that the Mg# characteristics of continental arc lavas match that of the continental *** findings suggest that the formation of many high-Mg#andesites and the continental crust may not require slab-melt/peridotite ***,the high Mg# of the continental crust can be explained by intracrustal calc-alkaline differentiation processes in magmatic orogens.

关键词： high-Mg# andesite calc-alkaline differentiation Fe depletion slab melting continental crust

Modeling the redshift and energy distributions of fast radio bursts

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Research in Astronomy and Astrophysics 2017年第2期17卷 22-28页

作者： xiao-Feng Cao ming xiao Fei xiao Department of Physics and Engineering Hubei University of Education Wuhan 430205 China

Abstract Fast radio bursts （FRBs） are one of the most mysterious astronomical phenomena nowadays. The identification of their origin requires more observations in the future and, importantly, deep un- derstandings of the existing observational data. By fitting the redshift and energy distributions of 15 Parkes FRBs, we try to derive their intrinsic energy function and the cosmic evolution of their burst rates. Specifically, while the energy function is assumed as usual to have a single-power-law form, the burst rates are considered to be proportional to the cosmic star formation rates by a redshift-dependent coefficient. Some plausible fittings are obtained, which indicate the power-law assumptions are feasible and effective. The values of the power-law indices could be used to independently constrain candidate FRB models, although parameter degeneracies still exist.

关键词： radio continuum general

Multiplicity of Solutions for a Class of Kirchhoff Type Problems

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Acta Mathematicae Applicatae Sinica 2010年第3期26卷 387-394页

作者： xiao-ming He Wen-ming Zou School of Science Minzu University of China Beijing 100081 China Department of Mathematical Sciences Tsinghua University Beijing 100084 China

In this paper we apply the （variant） fountain theorems to study the symmetric nonlinear Kirch- hoff nonlocal problems. Under the Ambrosetti-Rabinowitz＇s 4-superlinearity condition, or no Ambrosetti- Rabinowitz＇s 4-superlinearity condition, we present two results of existence of infinitely many large energy solutions, respectively.

关键词： Kirchhoff nonlocal problems Multiple solutions Fountain theorems

Analytical Bond-order Potential for hcp-Y

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Chinese Journal of Chemical Physics 2013年第5期26卷 526-532,I0003页

作者： Kai-min Fan Li Yang Jing tang Qing-qiang Sun Yun-ya Dai Shu-ming Peng xiao-song Zhou xiao--tao ZU School of Physical Electronics University of Electronic Science and Technology of China ChenEdu610054 China Department of Physics and Engineering Technology Sichuan University of Arts and Science Dazhou635000 China Department of Chemistry and Chemical Engineering Sichuan University of Arts and Science Dazhou635000 China School of Science Huaihai Institute of Technology LianyunEanE 222005 China Institute of Nuclear Physics and Chemistry China Academy of Engineering Physics Mianyang 621900China

The lattice parameters, elastic constants, cohesive energy, structural energy differences, as well as the properties of point defects and planar defects of hexagonal closepacked yttrium （hcpY） have been studied with ab initio density functional theory for constructing an ex tensive database. Based on an analytical bondorder poial scheme, empirical manybody interatomic potential for hcpY has been developed. The model is fitted to some properties of Y, e.g., the lattice parameters, elastic constants, bulk modulus, cohesive energy, vacancy formation energy, and the structural energy differences. The present potential has ability to reproduce defect properties including the selfinterstitial atoms formation energies, vacancy formation energy, divacancy binding energy, as well as the bulk properties and the thermal dynamic properties.

关键词： Hexagonal close-packed yttrium Bond-order potential Density functionaltheory Molecular dynamics

单一及多组分混合物绿松石仿制品的光谱学特征研究

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光谱学与光谱分析 2025年第1期45卷 183-190页

作者：杨池玉汪田田张维肖汤维茜同济大学浙江学院浙江嘉兴314051

对市场新出现的一类仿制品进行了拉曼光谱、红外光谱、化学成分、紫外-可见-近红外吸收光谱分析,对其主要谱学特征进行了归纳总结。结果表明这类仿制品主要由重晶石、三水铝石、方解石粉末单一组分或多组分混合压制再经环氧树脂类或丙... 详细信息

对市场新出现的一类仿制品进行了拉曼光谱、红外光谱、化学成分、紫外-可见-近红外吸收光谱分析,对其主要谱学特征进行了归纳总结。结果表明这类仿制品主要由重晶石、三水铝石、方解石粉末单一组分或多组分混合压制再经环氧树脂类或丙烯酸酯类有机物胶结,并经人工染剂染色而成。红外光谱显示:单一矿物组分仿制品和绿松石差异明显,重晶石仿制品显示[SO_(4)]^(2-)的1078 cm^(-1)吸收峰等,方解石仿制品显示[CO_(3)]^(2-)的1476±cm^(-1)吸收峰等;多组分仿制品可见综合了多种矿物特征的吸收光谱,谱学特征复杂。根据缺失水峰,或仅显示三水铝石结构水OH-导致的3623、3528、3472和3388 cm^(-1)吸收峰,指纹区显示[SO_(4)]^(2-)、[CO_(3)]^(2-)相关吸收峰,可初步区分于绿松石。显微拉曼光谱测试结果表明多组分仿制品的不同测试位置矿物组成不同,可分别测试到三水铝石(3360、3432、3522、3614 cm^(-1))、重晶石(989 cm^(-1))、方解石(1088 cm^(-1))的特征峰,结合显微拉曼光谱及化学分析结果可进一步确认仿制品的具体矿物组成。紫外-可见-近红外吸收光谱表明样品均经人工染剂染色,显示633±、713±nm吸收宽峰或610±、675±nm吸收宽峰。

关键词：三水铝石重晶石方解石振动光谱微区分析

Reductive smelting of spent lead–acid battery colloid sludge in a molten Na_2CO_3 salt

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International Journal of Minerals,Metallurgy and Materials 2015年第8期22卷 798-803页

作者： Yu-jie Hu Chao-bo tang Mo-tang tang Yong-ming Chen School of Metallurgy and Environment Central South University School of Metallurgy Engineering Hunan University of Technology

Lead extraction from spent lead–acid battery paste in a molten Na2CO3 salt containing Zn O as a sulfur-fixing agent was studied. Some influencing factors, including smelting temperature, reaction time, Zn O and salt dosages, were investigated in detail using single-factor experiments. The optimum conditions were determined as follows: T = 880°C; t = 60 min; Na2CO3/paste mass ratio = 2.8:1; and the Zn O dosage is equal to the stoichiometric requirement. Under the optimum conditions, the direct recovery rate of lead reached 98.14%. The results suggested that increases in temperature and salt dosage improved the direct recovery rate of lead. XRD results and thermodynamic calculations indicated that the reaction approaches of lead and sulfur were Pb SO4→Pb and Pb SO4→Zn S, respectively. Sulfur was fixed in the form of Zn S, whereas the molten salt did not react with other components, serving only as a reaction medium.

关键词： lead–acid batteries molten salts lead smelting des

A new imaging mode based on X-ray CT as prior image and sparsely sampled projections for rapid clinical proton CT

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Nuclear Science and Techniques 2023年第8期34卷 64-74页

作者： Yu-Qing Yang Wen-Cheng Fang xiao-Xia Huang Qiang Du ming Li Jian Zheng Zhen-tang Zhao Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China Shanghai Synchrotron Radiation Facility Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201204China Shanghai Key Laboratory of Cryogenics and Superconducting RF Technology ShanghaiChina Suzhou Institute of Biomedical Engineering and Technology Chinese Academy of Sciences SuzhouChina

Proton computed tomography(CT)has a distinct practical significance in clinical *** eliminates 3–5%errors caused by the transformation of Hounsfield unit(HU)to relative stopping power(RSP)values when using X-ray CT for positioning and treatment planning systems(TPSs).Following the development of FLASH proton therapy,there are increased requirements for accurate and rapid positioning in ***,a new rapid proton CT imaging mode is proposed based on sparsely sampled *** proton beam was boosted to 350 MeV by a compact proton linear accelerator(LINAC).In this study,the comparisons of the proton scattering with the energy of 350 MeV and 230 MeV are conducted based on GEANT4 *** the sparsely sampled information associated with beam acquisitions at 12 angles is not enough for reconstruction,X-ray CT is used as a prior *** RSP map generated by converting the X-ray CT was constructed based on Monte Carlo *** the estimation of the most likely path(MLP),the prior image-constrained compressed sensing(PICCS)algorithm is used to reconstruct images from two different phantoms using sparse proton projections of 350 MeV parallel proton *** results show that it is feasible to realize the proton image reconstruction with the rapid proton CT imaging proposed in this *** can produce RSP maps with much higher accuracy for TPSs and fast positioning to achieve ultra-fast imaging for real-time image-guided radiotherapy(IGRT)in clinical proton therapy applications.

关键词： Proton CT Real-time image guidance Image reconstruction Proton therapy

Design and performance of air flow-assisted ionization imaging mass spectrometry system

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Chinese Chemical Letters 2014年第5期25卷 687-692页

作者： Fei tang Yi Chen Jiu-ming He Zhi-Gang Luo Zeper Abliz xiao-Hao Wang State Key Laboratory of Precision Measurement Technology and Instruments Department of Precision InstrumentTsinghua University State Key Laboratory of Bioactive Substance and Function of Natural Medicines Institute of Materia MedicaChinese Academy of Medical Sciences and Peking Union Medical College

The imaging mass spectrometry（IMS） technology has experienced a rapid development in recent years.A new IMS technology which is based on air flow assisted ionization（AFAI） was *** allows for the convenient pretreatment of the samples and can image a large area of sample in a single measurement with high *** AFAI in DESI mode was used as the ion source in this *** new IMS method is named *** adoption of assisted air flow makes the sample pretreatment easy and *** optimization of the distance between the ion transport tube and MS orifice increases the sensitivity of the *** data processing,a program based on MATLAB with the function of numerical analysis was developed.A theoretical imaging resolution of a few hundred microns can be *** composite AFAI-IMS images of different target analytes were imaged with high sensitivity.A typical AFAI-IMS image of the whole-body section of a rat was obtained in a single analytical *** ability to image a large area for relevant samples in a single measurement with high sensitivity and repeatability is a significant *** method has enormous potentials in the MS imaging of large and complicated samples.

关键词： Imaging mass spectrometry Air flow assisted ionization imaging mass spectrometry Whole-body imaging Large and complicated sample imaging