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Automated estimation of stellar fundamental parameters from low resolution spectra: the PLS method

Research in Astronomy and Astrophysics 2009年第6期9卷 712-724页

作者： jian-Nan zhang A-li Luo Yong-Heng Zhao National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China

PLS （Partial Least Squares regression） is introduced into an automatic estimation of fundamental stellar spectral parameters. It extracts the most correlative spectral component to the parameters （Teff, log g and [Fe/H]）, and sets up a linear regression function from spectra to the corresponding parameters. Considering the properties of stellar spectra and the PLS algorithm, we present a piecewise PLS regression method for estimation of stellar parameters, which is composed of one PLS model for Teff, and seven PLS models for log g and [Fe/H] estimation. Its performance is investigated by large experiments on flux calibrated spectra and continuum normalized spectra at different signal-to-noise ratios （SNRs） and resolutions. The results show that the piecewise PLS method is robust for spectra at the medium resolution of 0.23 nm. For low resolution 0.5 nm and 1 nm spectra, it achieves competitive results at higher SNR. Experiments using ELODIE spectra of 0.23 nm resolution illustrate that our piecewise PLS models trained with MILES spectra are efficient for O ～ G stars： for flux calibrated spectra, the systematic offsets are 3.8%, 0.14 dex, and -0.09 dex for Teff, log g and [Fe/H], with error scatters of 5.2%, 0.44 dex and 0.38 dex, respectively; for continuum normalized spectra, the systematic offsets are 3.8%, 0.12dex, and -0.13 dex for Teff, log g and [Fe/H], with error scatters of 5.2%, 0.49 dex and 0.41 dex, respectively. The PLS method is rapid, easy to use and does not rely as strongly on the tightness of a parameter grid of templates to reach high precision as Artificial Neural Networks or minimum distance methods do.

关键词： methods data analysis -- methods statistical -- stars fundamental param- eters (classification, temperatures, metallicity) -- techniques spectroscopic -- surveys

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Shoot Apex Demand Determines Assimilate and Nutrients Partitioning and Nutrient-uptake Rate in Tobacco Plants

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Journal of Integrative Plant Biology 2007年第11期49卷 1654-1661页

作者： Huai-Yu Yang Chun-jian li Fu-Suo zhang The Key Laboratory of Plant Nutrition Ministry of Agriculture Key Laboratory of Plant-Soil Interactions Ministry of Education Department of Plant Nutrition China Agricultural University Beijing 100094 China

Our previous experiment revealed that apex-removed plants have larger root systems but a lower K＋-uptake rates than intact tobacco plants. Since the apex is not only a center of growth and metabolism, but also an important place of auxin synthesis and export, the aims of this study were to distinguish whether the apex demand or auxin synthesized in the apex regulates assimilate and nutrients partitioning within plant, and to explain the reason for the lower K＋-uptake rate of the apex-removed plant. In comparison with the control plant, covering the shoot apex with a black transparent plastic bag reduced net increases in dry matter and nutrients; however, the distribution of the dry matter and nutrients between shoot and roots and nutrient-uptake rates were not changed. Removal of the shoot apex shifted the dry mass and nutrients distributions to roots, and reduced the rate of nutrient uptake. Application of 1-naphthylacetic acid （NAA） could partly replace the role of the removed apex, stimulated assimilate and nutrient deposition into the treated tissue, and enhanced the reduced plasma membrane ATPase activity of roots to the control level. However, treatment of the apex-removed plants with NAA could not rescue the reduced nutrient uptake rate and the shifted assimilates and nutrients partitioning caused by excision of the apex. Higher nutrient uptake rate of the intact plants could not be explained by root growth parameters, such as total root surface area and number of root tips. The results from the present study indicate that strong apex demand determined assimilates and nutrients partitioning and nutrient-uptake rate in tobacco （Nicotiana tabacum） plants.

关键词： assimilate and nutrient partitioning auxin nutrient uptake removal of the shoot apex shoot apex demand tobacco (Nicotiana tabacum).

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Dioxygen Affinities and Catalytic Oxidation Performance of Cobalt (Ⅱ)Complexes with N—Aryl Hydroxamic Acid

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Chinese Chemical Letters 2003年第6期14卷 627-630页

作者： Chun Chun zhang Wei ZENG jian zhang li Sheng Ying QIN Department of Chemistry Sichuan UniversityChengdu 610064

The oxygenation of cobalt (II) hydroxamates (CoL2) and its catalytic performance in oxidation of p-xylene to p-toluic acid (PTA) were examined. The effects of X and Y bonded to hydroxamate group on dioxygen affinitie... 详细信息

关键词： Cobalt (II) hydroxamates dioxygen affinities catalytic oxidation p-xylene.

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An Open Access 4×4 MIMO Testbed and its Validation with an IEEE 802,11n WLAN System

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China Communications 2014年第A01期11卷 64-71页

作者： SUN jian li Fudong zhang Haixia jianG Mingyan YUAN Dongfeng SchoolofInformationScienceandEngineering ShandongUniversityJinan250100ShandongChina

Multiple-Input Multiple-Output （MIMO） and Orthogonal Frequency Division Multiplexing （OFDM） have been widely accepted as key techniques of the current and future wireless communication systems. In this paper, an open access MIMO testbed is presented, on which the researchers can demonstrate and evaluate their baseband algorithms over the real wireless channel, without knowing much details about the hardware of the testbed. Moreover, an IEEE 802.11n transmission scheme is implemented as a design example to validate this testbed as well as demonstrate the transmission characteristics of MIMO-OFDM.

关键词： open access testbed MIMO MIMO-OFDM IEEE 802.1 ln receiver algorithms

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AI-2 Key Enzyme S-Ribosylhomocysteinase from Strain Klebsiella pneumoniae CICC 10011 Producing 2,3-Butanediol

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Chemical Research in Chinese Universities 2011年第2期27卷 273-276页

作者： DAI jian-ying zhang li-fu XIU Zhi-long School of life Science and Biotechnology Dalian University of Technology Dalian 116024 P. R. China

S-Ribosylhomocysteinase（LuxS） is the key enzyme in the synthetic pathway of a quorum sensing autoinducer AI-2. LuxS from a 2,3-butanediol produced strain Klebisella pneumoniae CICC 10011 was cloned and characterized. The luxS gene is composed of 540 bp with 172 amino acids encoded. The Km value for S-ribosylhomo- cysteine（SRH） was （27±1） umol/L, kcat was （0.112±0.004） s-1 and kcat/Km was 4.4×103 L umol-1·s-1 at 25 ℃. LuxS was activated by divalent metal ions, the highest activity was detected with Co2＋ form, followed by Mg2＋, Ba2＋, Mn2＋, Fe2＋ and Ca2＋, and activation constant for Co2＋ is （16±2） umol/L.

关键词： S-Ribosylhomocysteinase(LuxS) Kinetics Characterization Klebsiellapneumoniae

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Synthesis and Crystal Structure of [Cd(NBA)(μ_3-OH)(4,4′-bipy)_(1/2)]_n

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Chinese Journal of Structural Chemistry 2007年第8期26卷 917-919页

作者： SHEN Yi-Cheng zhang jian li Zhao-Ji zhang Lei YIN Pei-Xiu YAO Yuan-Gen State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter The Chinese Academy of Sciences Fuzhou Fujian 350002 China

A new cadmium polymer [Cd（NBA）（μ3-OH）（4,4＇-bipy）1/2]n 1 （NBA=m-nitrobenzoic acid and 4,4＇-bipy=4,4-bipyridine） has been synthesized by hydrothermal reaction. Its structure was determined by single-crystal X-ray diffraction method, and characterized by elemental analysis and IR spectrum. The crystal is of monoclinic, space group C2/c, with a=15.6912（9）, b=25.9394（15）, c=6.7332（4）A, β=114.7700（10）°, V=2488.4（3）A^3, C12H9CdN2O5, Mr=373.61, Z=8, Dc=1.995 g/cm^3,μ=1.776 mm^-1, F（000）=1464, R=0.0411 and wR=0.1128 for 2130 observed reflections （I 〉 2σ（I））.X-ray diffraction studies reveal that the compound features a layered structure, in which 4,4＇-bipy ligands bridge Z type of double chains [Cd（μ3-OH）]n and NBA ligands locate at the two sides of the layer. The π-π interactions between the benzene rings of NBA ligands of two adjacent layers lead to the 3D framework.

关键词： cadmium polymer 4 4'-bipyridine m-nitrobenzoic acid crystal structure

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Preliminary study of the effects of EVA coupling agents on properties of wood-plastic composites

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Forestry Studies in China 2010年第2期12卷 90-94页

作者： li Dong-fang li li li jian-zhang College of Materials Science and Technology Beijing Forestry University Beijing 100083 P. R. China

As a hot-melt adhesive, ethylene-vinyl-acetate （EVA） has been used in many industrial applications. But studies of the application of EVA in wood-plastic composites （WPC） are relatively few, so we have investigated the proposition of whether EVA is a suitable coupling agent for WPC or not. The results show that EVA with 8% VA is not a suitable coupling agent, because it reduces the mechanical properties of WPC without any significant effect on its physical properties. With an increase in the amount of wood powder, the mechanical properties of WPC decrease and the ability of water absorption of WPC increases.

关键词： wood-plastic composites ethylene-vinyl-acetate coupling agent property

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Exploring changes of precipitation extremes under climate change through global variable-resolution modeling

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Science Bulletin 2024年第2期69卷 237-247页

作者： Wei Sun jian li Rucong Yu Nina li Yi zhang State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China Institute of Tibetan Plateau Meteorology China Meteorological AdministrationChengdu 610072China Department of Atmospheric Science Yunnan UniversityKunming 650091China National Meteorological Center China Meteorological AdministrationBeijing 100081China 2035 Future Laboratory PIESAT Information Technology Co.Ltd.Beijing 100105China

Understanding the responses of precipitation extremes to global climate change remains limited owing to their poor representations in models and complicated interactions with multi-scale *** we take the record-breaking precipitation over China in 2021 as an example,and study its changes under three different climate scenarios through a developed pseudo-global-warming(PGW)experimental framework with 60-3 km variable-resolution global ensemble *** to the present climate,the precipitation extreme under a warmer(cooler)climate increased(decreased)in intensity,coverage,and total amount at a range of 24.3%-37.8%(18.7%-56.1%).With the help of the proposed PGW experimental framework,we further reveal the impacts of the multi-scale system interactions in climate change on the precipitation *** the warmer climate,large-scale water vapor transport converged from double typhoons and the subtropical high marched into central China,enhancing the convective energy and instability on the leading edge of the transport *** a result,the mesoscale convective system(Mcs)that directly contributed to the precipitation extreme became stronger than that in the present *** the contrary,the cooler climate displayed opposite changing characteristics relative to the warmer climate,ranging from the large-scale systems to local environments and to the *** summary,our study provides a promising approach to scientifically assess the response of precipitation extremes to climate change,making it feasible to perform ensemble simulations while investigating the multi-scale system interactions over the globe.

关键词： Precipitation extreme Climate change Pseudo-global-warming experiment Variable-resolution modeling Multi-scale system interaction

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Special Expression of Thy-1 in Different Malignant Tumors

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Chinese Journal of Cancer Research 2010年第1期22卷 73-79页

作者： Jin-feng Chen Ai-ping Lu Nan Wu li-jian zhang Yue Yang Key Laboratory of Carcinogenesis and Translational Research （Ministry of Education Department of Thoracic Surgery Department of Pathology Peking University School of Oncology Beijing Cancer Hospital ＆ Institute Beijing 100142 China

Objective： To investigate the expression status of Thy-1 in malignant cancerous tissues and to evaluate whether Thy-1 could be a potential tumor marker. Methods： Immunohistochemistry method was used to examine Thy-1 expressions in different malignant tumor tissues. We used a monoclonal antibody specific for Thy-1 and the indirect Catalysis Signal Amplification method. With the help of tissue microarray （TMA）, we examined expression the status of Thy-1 in 1451 different types of malignant tumor tissues, 144 normal tissues and benign lesions. Results： All the malignant tumor cells were grouped as one group （malignant cells group） and normal or benign tumor tissue cells as another group （normal cells group）. Among the entire 1451 malignant cases group, positive Thy-1 expression with diffuse and strong staining was observed in 734 （734/1451; 50.59%） cases. In the benign cases only 6 chronic cervicitis cases showed weak staining for Thy-1. All the normal tissue showed negative staining. One-Way ANVOA analysis showed F value between these two groups was 147.229 （P〈0.0001）. Conclusion： A significantly stronger expression of Thy-1 in malignant tumors was observed. Special overexpression of Thy-1 in malignant tumors suggests that Thy-1 might be a potential novel tumor marker with respect to cancer progression. Chronic cervicitis has some relationship with cervix carcinoma. When it develops into atypical hyperplasia, it will be a precancerous lesion for cervix carcinoma. In this research we found weak staining for Thy-1 in chronic cervicitis lesion, so Thy-1 may play a crucial role in carcinogenesis for cervix carcinoma. The research about the relationship between Thy-1 expressions in cancer cells and in precancerous lesion will provide some clues to understand the mechanism for carcinogenesis process.

关键词： Thy-1/CD90 Malignant tumor Tumor marker

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Identification of potential oxidative stress biomarkers for spinal cord injury in erythrocytes using mass spectrometry

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Neural Regeneration Research 2021年第7期16卷 1294-1301页

作者： li-jian zhang Yao Chen Lu-Xuan Wang Xiao-Qing Zhuang He-Chun Xia School of Clinical Medicine Ningxia Medical UniversityYinchuanNingxia Hui Autonomous RegionChina Department of Neurosurgery General Hospital of Ningxia Medical UniversityYinchuanNingxia Hui Autonomous RegionChina Ningxia Human Stem Cell Research Institute General Hospital of Ningxia Medical UniversityYinchuanNingxia Hui Autonomous RegionChina Department of Nuclear Medicine General Hospital of Ningxia Medical UniversityYinchuanNingxia Hui Autonomous RegionChina

Oxidative stress is a hallmark of secondary injury associated with spinal cord *** stable and specific oxidative biomarkers is of important significance for studying spinal cord injury-associated secondary *** erythrocytes do not contain nuclei and mitochondria and cannot be transcribed and ***, mature erythrocytes are highly sensitive to oxidative stress and may become a valuable *** the present study, we revealed the proteome dynamics of protein expression in erythrocytes of beagle dogs in the acute and subacute phases of spinal cord injury using mass spectrometry-based *** found 26 proteins that were differentially expressed in the acute(0–3 days) and subacute(7–21 days) phases of spinal cord *** analysis revealed that these differentially expressed proteins were involved in glutathione metabolism, lipid metabolism, and pentose phosphate and other oxidative stress *** blot assays validated the differential expression of glutathione synthetase, transaldolase, and *** result was consistent with mass spectrometry results, suggesting that erythrocytes can be used as a novel sample source of biological markers of oxidative stress in spinal cord *** synthetase, transaldolase, and myeloperoxidase sourced from erythrocytes are potential biomarkers of oxidative stress after spinal cord *** study was approved by the Experimental Animal Centre of Ningxia Medical University, China(approval No.2017-073) on February 13, 2017.

关键词： acute phase bioinformatic analysis biomarkers central nervous system dog erythrocytes mass spectrometry oxidative stress peripheral blood spinal cord injury subacute phase

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